# UPDATE FOR ADVANCED TECHNOLOGIES TO IMPROVE FUEL ECONOMY OF LIGHT DUTY VEHICLES Draft Final Report

Submitted to: 

## US Department of Energy

August 2007

Submitted By: 

## Energy and Environmental Analysis, Inc. An ICF International CompanyEnergy and Environmental Analysis, Inc. i Table of Contents

1 OVERVIEW ....................................................................................................................... ................1-1

2 ADVANCED GASOLINE ENGI NE TECHNOLO GIES .....................................................................1-1
2.1 INTRODUCTION AND BASEL INE FOR ANAL YSIS................................................................1-2 2.2 ENGINE TECHNOLOGY DEVELOPMENT TRENDS .............................................................1-4 2.3 CONTINUOUSLY VAR IABLE VALVE LIFT ............................................................................. 1-8 2.3.1 BMW Valvet ronic................................................................................................................ ..1-9 2.3.2 Nissan/Hitachi CVVL ............................................................................................................ 1-9 2.3.3 Toyota Valvematic.............................................................................................................. 1-11 2.3.4 Honda AVTEC.................................................................................................................... 1-12 2.3.5 Hilite Univ alve® ............................................................................................................... ...1-14 2.3.6 CVVL Summary a nd Analys is ............................................................................................1-16 2.4 CAMLESS VALVE AC TUATION ............................................................................................1-18 2.4.1 Valeo Camless Smart Valv e Actuation - SVA....................................................................1-18 2.4.2 Analysis for Camless Valve Actuat ion................................................................................1-21 2.5 DIRECT INJECTION SI TECHNOLOGY................................................................................1-22 2.5.1 Natural Aspirated Stoichiome tric DISI E ngines..................................................................1-23 2.5.2 Turbocharged Stoichiometr ic DISI E ngines .......................................................................1-27 2.5.3 FEV Turbo DI, VCR, Flex Fuel Engine Concept ................................................................1-31 2.5.4 Spray Guided DI SI Engi nes ...............................................................................................1-32 2.5.5 Direct Injection Summa ry and Anal ysis..............................................................................1-39 2.6 REFERENCES FOR SECTION 2 ..........................................................................................1-44
3 ADVANCED TRANSM ISSIONS .......................................................................................................2- 1 3.1 INTROD UCTION ............................................................................................................... .......2-1 3.2 AUTOMATIC TRAN SMISSIONS..............................................................................................2-2 3.2.1 Mercedes 7G-Tronic, 7-Speed Automatic Tran smission .....................................................2-2 3.2.2 Toyota/Aisin 8-Speed Auto matic Transm ission ...................................................................2-4 3.2.3 ZF 8-Speed Automatic Transmissio n...................................................................................2-6 3.3 AUTOMATED MANUAL TRANSMISSI ONS ............................................................................ 2-7 3.4 CONTINUOUSLY VARIABL E TRANSMISSI ONS.................................................................... 2-9 3.5 ADVANCED TRANSMISSION SUMMARY AND AN ALYSIS ................................................2-10 3.6 REFERENCES FOR SECTION 3 ..........................................................................................2-14
4 DIESEL AND HYBRI D UPDAT E ......................................................................................................3 -1 4.1 LIGHT DUT Y DIESELS ......................................................................................................... ...3-1 4.1.1 Diesel Technology Advances...............................................................................................3-2 4.1.2 Diesel Exhaust Aftertreatm ent to Reach Bin 5.....................................................................3-5 4.1.3 Diesel Summary a nd Analysis..............................................................................................3-6 4.2 HYBRID TE CHNOLO GY........................................................................................................3- 10 4.2.1 General Hybrid Pr oduct Trends..........................................................................................3-10 4.2.2 Supplier Announ cements ...................................................................................................3-13 4.2.3 Summary and A nalysis .......................................................................................................3-15 4.3 REFERENCES FOR SECTION 4 ..........................................................................................3-20ii Energy and Environmental Analysis, Inc. List of Figures

Figure 2-1. Relative Costs and Fuel Consumption (C O2) Reduction for Various Engine Technologies...1-4 Figure 2-2. Overview of Fuel Economy Potential. ................................................................................ .....1-6 Figure 2-3. Pathways for Future Tu rbocharged Engine Evoluti on.............................................................1-7 Figure 2-4. Costs vs. Benefits for Vari ous Advanced Engine Technologies . ............................................1-8 Figure 2-5. Hitachi/Nissan CVVL Mechanical Impl ementation ................................................................1-10 Figure 2-6. Toyota Valv ematic CVVL T System. .................................................................................... ..1-11 Figure 2-7. Honda’s CVVL Mech anical Implemen tation .........................................................................1-1 3 Figure 2-8. Hilite Univalve® Me chanical Implementation .......................................................................1 -15 Figure 2-9. Fuel Consumption for Hilite UniValve® De rivatives Compared to Other Valve Train Options. 1- 16 Figure 2-10. Valeo Electr omagnetic CVA Design.................................................................................. ..1-19 Figure 2-11. Valeo’s Camless Valve E ngine Fuel Consumpt ion Benefit s...............................................1-20 Figure 2-12. Toyota 3.5L V6 Dual Injection Engi ne Combustion Chamber Cutaway and Engine Map. 1-24 Figure 2-13. LS 460 and LS430 Fuel Economy Comp arison. Contribution of Various Engine Technologies................................................................................................................... .........................1-25 Figure 2-14. Toyota New 4.6L V8 Fuel Consum ption Comparison to pr evious 4.3L V8.........................1-26 Figure 2-16. Fuel Consumption Reduction for Various B oosting Options vs. Relati ve Cost Increases ..1-27 Figure 2-16. VW TSI Engine Relati ve Performance and Fuel Consum ption (CO2 Reduction)...............1-29 Figure 2-17. VW New 1.4L Downsized TSI E ngine Performance Compar ed to 1.6L FSI.......................1-30 Figure 2-18. Audi A3 Acceleration (80 to 120 km/h ) and Fuel Consumption Comparison among Different Engine Options (E uropean Data)................................................................................................. ............1-31 Figure 2-19. FEV VCR Mechanism and Potential Fuel Economy Contributions from Various Technologies.

............................................................................................................................... ..................................1-32 Figure 2-20. BMW Spray Guided Stratified HPI Combustion Cham ber Cutawa y. ..................................1-33 Figure 2-21. Fuel Consumption and Performance of BMW 335i Compared to Competition...................1-34 Figure 2-22. BMW New 3L I6 HPI Engine Map, Fuel Consumption and Op erating M odes. ................... 1-35 Figure 2-23. Driving performance and fuel consumption for BMW 530i and BMW 120i with new I6 and I4 engine s........................................................................................................................ .............................1-36 Figure 2-24. Mercedes Spray-Guided DISI Combustion Ch amber Desi gn.............................................1-37 Figure 2-25. Mercedes Stratified Charge Region Ma p and Fuel Consumption Reduction Potential as Compared to PFI................................................................................................................ ......................1-38 Figure 2-26. Mercedes CLS350 CGI Ex haust System Conf iguratio n......................................................1-38 Figure 2-27. BMW Estimates for SI Engine Specific Power and Fuel Consumption Reduction Benefits for Various Advanced Technol ogies. ................................................................................................. ...........1-40 Figure 2-28. Fuel Consumption (C O2) Reduction Potential for Va rious Engine Technologies...............1-41 Figure 2-29. Audi 2L TFSI Fuel Consumpt ion and Performance Progression. ......................................1-42 Figure 3-1. Merc edes 7G-Tronic................................................................................................. ...............2-3 Figure 3-2. Mercedes S500 Fuel Efficien cy Comparison, 7G-T ronic vs. 5AT...........................................2-4 Figure 3-3. Fuel Economy Improvemen t, Lexus LS, 8-spe ed vs. 6-s peed................................................ 2-5 Figure 3-4. ZF’s New 8-Speed Automatic Tran smissi on. ..........................................................................2 -6 Figure 3-5. Fuel Efficiency Improvement fo r Various ZF Transm ission Designs.......................................2-7 Figure 3-6. Cross Section of Ne w 7-speed AMT fr om VW. .......................................................................2-8 Figure 3-7. Fuel Consumption Comparison of Different Transm ission Designs from VW. .......................2-9 Figure 3-8. Bosch CVT Technology Expect ed Fuel Efficiency Improvement s. .......................................2-10 Figure 4-1. Diesel Efficiency Comparison versus Gasoline by Weight, Expressed as CO2. ....................3-1 Figure 4-2. Fuel Consumption Improvement of BM W’s New 2.0L Diesel Compared to the Previous Genera tion. .................................................................................................................... ............................3-3 Figure 4-3. Fuel Consumption and Performance of New BMW 1-Series Diesel Compared to Previous Generation Diesel Vehicles..................................................................................................... ...................3-4 Figure 4-4. Honda Diesel Tech nology for the US Market.......................................................................... 3-4 Figure 4-5. Basic Configurations for Urea-SCR and LNT-based Diesel Aftertre atment............................3-5 Figure 4-6. Relative Cost Comp arison between Lean NOx Trap (L NT) and Urea-SCR Catalysts. ..........3-6Energy and Environmental Analysis, Inc. iii Figure 4-7. Honda Civic HEV 2 nd Generation Technology Improvem ents............................................... 3-10 Figure 4-8. Toyota Hybrid Power Control Unit Relative Power D ensity Increase, MYs 2004-2007........3-11 Figure 4-9. GM Hybr id Product Plan............................................................................................. ...........3-12 Figure 4-10. Valeo StARS Strategy and Fuel Econom y Benefit s............................................................ 3-14iv Energy and Environmental Analysis, Inc. List of Tables
Table 2-1. MY 2005 Engine Valvetrain Technology Penetrati on by OEM.................................................1-3 Table 2-2. EEA 2006 Fuel Economy Benef its for Engine Te chnologie s ...................................................1-4 Table 2-3. Fuel Economy Benefits fo r Various Intake-C VVL Designs .....................................................1-16 Table 2-4. RPE [$] Estimates for Inta ke-CVVL, by Engine C onfigurati on. .............................................. 1-17 Table 2-5. Camless Intake RPE Cost Es timates by Engine C onfigurati on.............................................. 1-21 Table 2-6. EEA Estimates for Fuel Economy Benefit s and Costs for Various DISI Technologies..........1-39 Table 2-7. Summary Fuel Economy Gain Estima tes for Various DISI Technologies and EEA New Recommendations. ............................................................................................................... ...................1-43 Table 2-8. Technology Cost Estima tes Derived from Bosch Da ta...........................................................1-43 Table 3-1. MY 2005 Transmission Penetration by Ty pe and OEM. ..........................................................2-2 Table 3-2. EEA Earlier Estimates for Fuel Economy Benefits and RPE Increase, Compared to 4-Speed AT............................................................................................................................. ................................2-11 Table 3-3. MY 2007 Vehicle Fuel Economy Co mparison, CVT vs. 4-sp eed AT or Manual .................... 2-13 Table 4-1. Light Duty Diesel Fuel Ec onomy Improvement and $RPE Increa se........................................3-6 Table 4-2. MY 2007 LD Diesel Fuel Economy Comparison against Gasoline Models on Equal Displacement Basis............................................................................................................. .......................3-8 Table 4-3. MY 2007 LD Diesel Fuel Economy Comparison against Gasoline Models on “Competitive Performance” Basis............................................................................................................. .......................3-9 Table 4-4. Fuel Economy Impr ovement Potential of Various Hybrid Technologies. ...............................3-14 Table 4-5. Hybridization RPE Increa se and Fuel Econom y Benefit s.......................................................3-15 Table 4-6. MY 2007 Hybrid Vehicle Fuel Econom y, Key Specification and MSRP Comparison on Constant Displacement Basis. ................................................................................................... ..............3-16 Table 4-7. MY 2007 Hybrid Vehicle Fuel Econom y, Key Specification and MSRP Comparison on “Competitive Perfor mance Basis”. ............................................................................................... ............3-18Energy and Environmental Analysis, Inc. 1
‐ 1 

# 1 OVERVIEW

Fuel economy has become a focus of legislative activity in response to concerns about green house gas related emissions and high f uel prices. Fuel economy standards are set by cost benefit analyses that equate the cost of tec hnological improvements to
vehicles to the benefits realiz ed from fuel consumption reduc tion and allied benefits of reduced GHG emissions and improved energy security. Hence, good information on technology attributes to improve fuel economy is essential to t he regulatory process. Technology continues to develop at a r apid pace and, hence, periodic analyses of technologies are required to maintain an up-to -date list of technologies and their costs and benefits. EEA has provided the Department of Energy with such periodic analyses and this report is an update of a report co mpleted in early 2006 that focused on technologies to improve light truck fuel economy. While the technologies to improve cars (light duty vehicles) are ve ry similar or identical to t he technologies to improve light truck fuel economy, this report also has a greater focus on light duty vehicle fuel economy. The report focuses only on those technologies where new information has
become available in th e 2006-2007 time frame.
Section 2 examines new engine technolog ies and new data has become available on gasoline direct injection (GDI ), both stoichiometric and lean burn type, variable valve timing, camless valve actuation, and tu rbocharged GDI engines. Section 3 examines data on new transmission technologies, notably the new 7-speed and 8-speed automatic transmissions, double clutch automated manual transmissions and the continuously variable transmission. Secti on 4 updates an earlier ( 2004) EEA report on hybrid and diesel technologies. The resu lts presented in Section 2, 3 and 4 are expected to be used in other subsequent reports that estimate the fleet fuel economy potential for the next 20 years.Energy and Environmental Analysis 1
‐ 2 Advanced Gasoline Engine Technologies 

## 1.1 Introduction and Baseline for Analysis
This section examines advanced SI engi ne technology developments and associated fuel economy improvement announcements. EEA’s updated analyses for fuel economy benefits, and costs for these technologies are provided in this section. The analysis builds upon the fuel economy and cost estima tes documented in EEA’s previous report (EEA 2006). 1 As before, all technology-based fuel economy benefits and associated costs are with specific reference to a “ baseline” engine, defined as a typical 4-valve OHC (single or double camshaft) engine of 2000+ design vintage with fixed valve timing. Of course, the actual fleet consists of many engine des igns of different vintages and different architecture, with differing tec hnology levels. Hence, the baseline by
manufacturer can be a determinant of futu re technology potential since some manufacturers have already adopted several te chnologies widely while others have only recently begun adopting these technologies. Da ta for the 2005 fleet is presented to show baseline technology penetration by manufacturer.

As shown in Table 2-1, engines with va riable valve actuation are widely used in production. The most common systems use VVT (Variable Valve Timing) to control the valve opening timing, while the valve lift is fixed. The VVT technology penetration data, by OEM indicates that US manufacture rs are behind the Japanese in VVT adoption rates. DaimlerChrysler did not market the technology in MY 2005, although their newest engines, such as the Global I4, were des igned with VVT. The VVT adoption rate differences can also be partially explained by valve train configuration types since OHV engines are generally more difficult to modi fy for advanced valve technologies. GM still
uses the OHV architecture in most of thei r engines, while Daimle rChrysler’s HEMI V8 OHV engine is a popular option in trucks. The MY 2005 data illustrates that Japanese OEMs are not using OHV engine designs. All of their engines in cars feature DOHC 4- valve technology. Nissan and Toyota provide the same technology in trucks. Some Honda LDT engines feature single camshaf t (OHC) but, once again, with 4-valve configuration. The valve lift control devices are le ss common and typically are implemented in a two-step (or discrete) ca m profile switching arrangement. Among theEnergy and Environmental Analysis, Inc. 1
‐ 3 6 major OEMs, Honda is the only manufacturer that achieved high market penetration with their VTEC (with 2-st ep and 3-step VVL) engines.

Table 1-1. MY 2005 Engine Valve trai n Technology Penetration by OEM. Blank cells indicate “zero” penetration

. 2 Valve 3 Valve 4 Valve OHV OHC DOHC VVL VVT Light Duty Vehicles Daimler Chrysler 11.74% 4.94% 83.32% 11.74% 50.84% 37.43% Ford 39.71% 60.29% 14.33% 33.79% 51.88% 34.68% GM 67.84% 32.15% 61.95% 38.05% 12.27% Honda 100.00% 60.32% 39.68% 75.13% 75.13% Nissan 100.00% 100.00% 99.74% Toyota 100.00% 100.00% 100.00% Light Duty Trucks Daimler Chrysler 75.01% 24.99% 46.41% 44.42% 9.17% Ford 43.15% 27.92% 28.93% 11.99% 63.05% 24.97% 18.05% GM 67.84% 31.19% 67.73% 1.73 % 30.54% 17.97% Honda 100.00% 66.67% 33.33% 100.00% 83.48% Nissan 100.00% 100.00% 79.07% Toyota 100.00% 100.00% 98.71%
Direct Injection Spark Ignition (DISI) is a ne w engine technology with significant fuel economy improvement potential, particularly as implement ed with turbo-charging and engine downsizing strategies. The current market penetration fo r turbocharged engines is very limited. GM and DaimlerChrysler offe red the technology on selected sports and luxury models in MY2007 and all engines were conventional port injection (PFI). Turbocharger penetration for VW even in 2005 is substantial at 32.8% and the company offered both PFI and DISI tu rbocharged engines. The DI turbo engine was new for 2005 and VW has since expanded this offering to more models. DaimlerChrysler is the only major OEM that offers a tur bocharged engine in the LDT categor y (in the PT Cruiser). Most non-turbocharged engines wit h port fuel injection have a compression ratio (CR) of
9.7 + 0.1 in 2005, while turboc harged engines have compression ra tio of 8.1 to 8.8. The VW direct injection engine has CR of 12.5.Energy and Environmental Analysis 1
‐ 4 

## 1.2 Engine Technology Development Trends

New information available in the literatur e was utilized to evaluate the technology benefits reported by EEA last y ear as shown in Table 2-2, and our evaluation indicates only modest changes in attribut es for select technologies.

For example, Renault has made available re sults of their advanced technology fuel efficiency improvement assessment, which is based on NEDC testing. 2 While details of the cost analysis were not disclosed, the fuel efficiency improvement figures are available (see Figure 2-1). Renault’s cost curv e starts with VVT (about 3% fuel economy (FE) improvement). In the mi d-range, the downsized PFI (wit h turbo-charging) is shown to provide about 13% fuel consumption impr ovement (15% FE, which compares to EEA 2006 more conservative 7% on the US combined cycle). Renault argues that diesels provide about 22% CO2 reduction (over 40% FE improvement when converted to volumetric fuel economy im provement), which is hig her then the EEA 2006 analysis.

Figure 1-1. Relative Costs and Fuel C onsumption (CO2) Reduction for Various Engine Technologies. Source: Renault European data, with PFI fi xed valve timing technology as the base.Energy and Environmental Analysis, Inc. 1
‐ 5 TABLE 1-2: EEA 2006 FUEL ECONOMY BENEFITS FOR ENGINE TECHNOLOGIES
CONSTANT ENGINE SIZE CONSTANT PERFORMANCE SYSTEM FE BENEFIT TORQUE INCREASE FE BENEFIT ENGINE SIZE ADJUSTMENT INTAKE CAM PHASER DOHC 1.4 + 0.3 3.5 + 0.5 1.5 + 0.3 0
SINGLE CAM PHASER (SCP) – SOHC/OHV 1.6 + 0.3 3.5 + 0.5 1.6 + 0.3 0
DUAL CAM PHASER – DOHC 2.2 + 0.4 5.0 + 0.5 2.2 + 0.4 0
TWO STEP VVL 3.5 + 0.5 0 3.5 + 0.5 0 TWO STEP VVL + SCP 5.0 + 0.6 6.0 + 0.5 6.4 + 0.6 -6 + 0.5 TWO STEP VVL + DCP 6.4 + 0.6 7.0 + 0.5 8.0 + 0.6 -7 + 0.5 THREE STEP VVL + DCP 6.7 + 0.6 7.0 + 0.5 8.2 + 0.6 -7 + 0.5
CONTNUOUS VVL 8.0 + 1.0 10.0 + 0.5 10.0 + 1.2 -10 + 0.5 CYLINDER CUT OUT 6.6 + 1.0 0 6.6 + 1.0 0 CYLINDER CUT + TWOSTEP VVL +SCP 10.0 + 1.2 6.0 + 0.5 11.2 + 1.3 -6 + 0.5
CAMLESS VALVE ACTUATION (em) 13.6 + 1.5 12.0 + 2 16.0 + 2.0 -12 + 2 DIRECT INJECTION (DI) 3.5 + 0.5 5.0 + 0.5 3.5 + 0.5 0 DI +DCP 5.5 + 0.6 10.0 + 1.0 7.5 + 0.8 -10.0 + 1.0 TURBOCHARGING -1.0 + 0.3 37.0 + 3.0 7.0 + 1.3 -32.0 + 2.0 DI + DCP + VNT (TURBO) 4.2 + 1.0 40.0 + 3.0 14.0 + 1.2 -35.0 + 2.0 (fewer cyl.) ROLLER CAM FOLLOWERS 2.0 + 0.2 0 2.0 + 0.2 0 Engine Friction Red. I (1995+ design vintage) 2.0 + 0.2 0 2.0 + 0.2 0 Engine Friction Red. II (2001+ design vintage) 1.5 + 0.1 0 1.5 + 0.1 0 Engine Friction Red. III 1.5+ 0.1 0 1.5 + 0.1 0 Engine Friction Red. IV 1.5 + 0.1 0 1.5 + 0.1 0Improved Lube Oil (5W20) 1 + 0.1 0 1 + 0.1 0 All benefits are in percent relative to port f uel injected engine with fixed valve timing. All benefit estimates assume shift point optimiz ation to suit changes to the torque curve.Energy and Environmental Analysis 1
‐ 6 Another new example by Siemens VDO (see Figure 2-2) provides a similar assessment, once again, based on NEDC testing. 3 Siemens’ analysis is more detailed since it provides the minimum and maximum ranges for fuel efficiency improvement. At the smaller FE improvement range, VVT (Cam phasing) is shown to provide a minimum of about 2% FE improvement (EEA 2006 - up to 2.2%). The cylinder cut shows 4 to 8% FE gain, which matches well with the EEA nominal 6.6%. The Variable Valve Lift and Timing (VVLT) is shown to provide a 7% to 9% FE gain, which can be compared to EEA
minimum 8 + 0.6 % (two-step VVL plus dual cam phaser).

Figure 1-2: Overview of Fuel Economy Potential.

Source: Siemens VDO Automotive Auto manufacturers generally agree that the combination of turbo- charging, downsizing and DISI will be one of the major technologi es capable of double-digit fuel economy improvements. GM has looked into this te chnology in great detail and publicized their assessment in the 2007 Vienna Engine Technology Conference. 4 GM is already marketing a few turbocharged engines, includi ng the 2.0L Ecotec, which also features DISI. GM is recognizing that, so far, the technology was used to dramatically increaseEnergy and Environmental Analysis, Inc. 1
‐ 7 performance but, in the future, downsizing is another technology pathway that can
achieve substantial fuel economy improvements.

Figure 2-3 provides a pictor ial illustration of the downs ized (or enhanced performance) and turbocharged engine pathways from GM ’s perspective. The company has
demonstrated that turbo-c harging and downsizing can be executed in numerous configurations and can be used for both PF I and DISI engines. The package with the most promising fuel economy improvement potential is DI SI with variable geometry turbo-charging and VVT (valve phasi ng), which agrees with the EEA 2006 DI+DCP+VNT pathway. Inform ation presented in subsequent sections shows that GM and EEA fuel economy estimates are similar for DISI Turbo technologies. GM further argues that all downsizing and DISI turbo pack ages would work well with hybridization, since the turbo lag issue can be minimized with the electric motor power assist.

Figure 1-3: Pathways for Future Turbocharged Engine Evolution.
Source: GMEnergy and Environmental Analysis 1
‐ 8 Technology costs are the most controve rsial research area and detailed public information is very limited and is often biased to ward a particular researcher or industry. EEA did obtain a generalized cost assessment from Bosch and Figure 2-3 summarizes
this data. 5 The Bosch cost estimates are used in this report in subsequent sections to assess EEA’s earlier analysis for discrete technology costs.

FIGURE 1-4. COSTS VS. BENEFI TS FOR VARIOUS ADVANCED ENGINE TECHNOLOGIES.
Source: Bosch 

## 1.3 Continuously Vari able Valve Lift
The only CVVL system cu rrently in the market is BMW’s Valvetronic, which achieves a
combination of both lift and valve opening duration change via an intermediate lever mechanism working in conjunction with cam p hasers. CVVL technology, also known as “intake throttling”, allows elimination of the engine throttle unit when implemented withEnergy and Environmental Analysis, Inc. 1
‐ 9 intake VVT. This type of engine can be cont rolled through real time adjustment of the inlet valve lift and intake valve opening times.

1.3.1 BMW Valvetronic The Valvetronic system adjusts the valve lift using a lever positioned between the
camshaft and the intake valves. The dist ance from the camshaft is adjusted by additional eccentric shaft operat ed by an electric motor.

BMW started Valvetronic marketing on its higher-end lineup but now the technology is available on most engines. BMW has claime d that the system achi eves a fuel economy improvement of about 12%, but that this includes the benefit of dual cam phasers and reduced friction. Subtracting t he VVT benefits, the system is expected to yield about 8% fuel economy improvement. This comparison is for FTP cycle conditions and relative to PFI (Port Fuel Injected) engine with fix ed valve timing and compression ratio.

1.3.2 Nissan/Hitachi CVVL Hitachi has developed a CVVL system, they call VVEL (Var iable Valve Event and Lift), which is scheduled to be launched on the MY 2008 Infinity G37 Coupe. 6, 7 The system is designed to throttle the intake valves and works in conjunction with VVT control.

Figure 2-5 illustrates the CVVL mechanical implementation. The pr ofile of the output cams incorporates ramp section for obtaini ng smooth lift. The center position of the
drive shaft is the same as t hat of ordinary camshafts. Driven by a chain, the drive shaft undergoes rotational motion that is synchr onized to one-half the rotation of the
crankshaft. An eccentric driv e cam attached to the drive shaft converts the rotational
motion of the drive shaft to osc illatory motion that is transf erred to the oscillating output cams by the Link A, rocker arm and Link B. The DC motor mechanism adjusts the link
and rocker arm kinematics to obtain cont inuous adjustment of the valve lift.Energy and Environmental Analysis 1
‐ 10 Figure 1-5. Hitachi/Nissan CVVL Mechanical Implementation
Engine developers reported that , at low-to-mid load ranges, the intake throttling optimizes the air charge volume. Less valv e travel reduces camshaft friction and improves acceleration response by allowing more dense air into the cylinders from the start of acceleration. The timing control opens the valves for a shor ter period, preventing
blowback of the air-fuel mixt ure and improving torque. In the high load range, the valve
lift is increased which allows increased air intake to deliver greater torque outputs.

For reduced emissions, the intake-valve timi ng is optimized for cold startup to increase the temperature of exhaust gases and more qui ckly activate the catalytic converter. Intake throttling also impr oves fuel/air mixture fo rmation and emissions through increased velocity and turbulence.

The VVEL improves fuel efficiency most e ffectively in the low-to-medium operating range, thus it is best matched to higher di splacement engines that typically operate within that range. Nissan has indicated that in high-disp lacement engines the companyEnergy and Environmental Analysis, Inc. 1
‐ 11 will combine VVEL technology with the dire ct-injection system. Also the system is capable of “zero lift”; ther efore cylinder deactivation is possible in the future.

Nissan and Hitachi claim that VVEL adoption, together with VVT, provides up to 20% more power and up to 12% fuel economy im provement (cycle conditions were not reported). This comparison is against an identical engine without CVVLT, implying a fixed valve timing engine.

1.3.3 Toyota Valvematic Toyota announced that it has developed a commercial-ready CVVL system, called Valvematic, which is also designed to work with VVT (Toyota’s version, VVT-i -Variable Valve Timing-intelligent). 8 The new system allows fully flexible intake adjustment and eliminates the need for an engine throttle unit. As indicated in Figure 2-6, the overall system implementation is similar to other mechanical CVVL trains.

Figure 1-6. Toyota Valvematic CVVLT System. Toyota announcements indicate that the system , installed on a new 2.0L engine (which does include undisclosed additional modifications), improves fuel consumption by 5% to 10% (implying up to 11% fuel economy impr ovement, depending on driv ing conditions), boosts output by at least 10% and enhances acceleration responsiveness. TheEnergy and Environmental Analysis 1
‐ 12 comparison is likely against the baseline of current Toyota engines all of which feature VVT, although cycle conditions are not specified.

1.3.4 Honda AVTEC Honda has announced development of the next generation VTEC (Variable Valve Timing and Lift Electronic Control) engine, called AVTEC (or Ad vanced VTEC). The new system will combine the continuously vari able valve lift system (intake only) with continuously variable timing control. 9

Figure 2-7 explains how the system works. To allow the valve lift and timing to be varied, the mechanism (1) comp rises a camshaft (8) with cams (7), and a pivoting first rocker arm (9). The first rocker actuates the end of valve stem (12). The key part of the design is a drum (11) which surrounds t he camshaft but provides enough opening for the cam/follower engagement.

The drum supports the second rocker arm (1 0) through pivot point (20). The second rocker-end incorporates the cam follower (21). The result is that the other end of this rocker (22) actuates the firs t rocker arm. The valve lift and timing is therefore dependent on the position of the second ro cker arm, which in turn is regulated by the drum angular position. The drum position is adjus ted through control members (25, 26).

Similar to other intake valve thrott ling designs, Honda’s AVTEC system enables
elimination of the tr aditional butterfly throttle. The valve events are then controlled according the following principal modes:

Low-Load. Intake valves close early to achieve a lowered and narrower lift period. Since resulting pumping losses after intake closure can be compensated during the compression stroke, overall pumping losses ar e lower. Also throttled intake increases air charge velocity and turbulence, im proving mixture formation and combustion efficiency.Energy and Environmental Analysis, Inc. 1
‐ 13 Figure 1-7. Honda’s CVVL Mechanical Implementation 10Energy and Environmental Analysis 1
‐ 14 Medium-Load. The controller creates intake and ex haust valve overlap by advancing the intake valve timing to achieve controlled internal EGR. The result is improved fuel consumption and reduced emissions.

High-Load. The valve lift is set high and openi ng period is widened for improved charging efficiency and performance.

The ability to continuously adjust the trans ition between these modes is crucial in successful system application. Honda has deve loped a sophisticated controller for this design, which allows smooth transition to different engine speeds, optimizing fuel consumption, emissions and performance.

Among many resulting efficiency improvement s the new controller allows idle speed
reduction from 850RPM to 600RPM and still achi eves smooth idling. Honda claims that this strategy alone resulted in fuel econom y improvement of about 1.7% in the FTP cycle. 11

Overall, the new AVTEC system is claimed to allow for a 13% improvement in fuel economy over the current VTEC engines wit h significant torque increase. Honda’s announcements were made in the US so the co mparison is potentially for the FTP cycle
conditions.

1.3.5 Hilite Univalve®

Hilite International has announced that the company is refining its versions of DVVL technology, called UniValve®, which was developed together with EnTec Consulting. 12 The mechanical implementation of the C VVL function is accomplished through the
eccentric control shaft that contacts an additi onal link in the valve tr ain, the intermediate
lever. This additional lever does not have a fi xed pivot shaft and is held in position by guide and spring. The eccentric shaft moves the lever and controls the bottom “working curve” engagement with the roller rocker finger . The eccentric control is driven by electric motor via worm gear pair. Fi gure 2-8 shows how the CVVL function is accomplished by this system.Energy and Environmental Analysis, Inc. 1
‐ 15 Figure 1-8. Hilite Univalve® Mechanical Implementation 13
The mechanism is designed to operate on engines with two valves for the intake side.
The intermediate rocker arms for each intake valve pair are constructed in a fork arrangement. Because of this paired arr angement, Hilite’s design allows the fork actuation by separately controlled eccentric shaft. This concept is called “cylinder up loading”. The company argues that independent lift control on different cylinders can achieve additional fuel consumption savi ngs although issues, such as increased vibration and noise, as well as additional controller complexity, still need to be

overcome.

Hilite has shown that the UniValve®, w hen working in combination with dual cam phasers, can achieve up to 13% fuel c onsumption improvement . When combined with cylinder up loading, the total benefit is 15% (NEDC cycle). Hilite’s system comparison to
other mainstream valve act uation technologies, such as two-step VVL and dual VVT, is provided in Figure 2-9.Energy and Environmental Analysis 1
‐ 16 75 80 85 90 95 100 105

Basic Engine Two-Step Cam Contour Switching Intake and Exhaust

Cam Phasers Two-Step Cam Contour Switching + Dual Phasers Univalve + Dual Phasers Univalve + Dual Phasers + Cylinder Up

LoadingFuel Consumption [%]

Load Point: 2,000RPM, BMEP=2 Comparison is for NEDC cycle at constant engine size Figure 1-9. Fuel Consumption for Hilite UniValve® Derivatives Compared to Other Valve Train Options.

1.3.6 CVVL Summary and Analysis Most OEMs have been reluctant to adopt C VVL because of added cost and complexity, which can degrade engine reliability. Ho wever numerous new announcements by Japanese OEMs indicate that commercialization for the mass market vehicle can be expected in the near future. 14 Table 2-3 summarizes the fu el economy improvements for
intake-CVVL from various des igns highlighted above.

Table 1-3. Fuel Economy Benefits for Various Intake-CVVL Designs. Comparison is against PFI engine with fi xed valve timing/lift and fixed CR, with exception of Honda AVTEC, as noted. System Fuel Economy Benefit [%] VVT Included in FE Benefit? Notes

BMW Valvetronic Up to 12 Yes NEDC Nissan CVVL Up to 12 Yes Unspecified cycle Toyota Valvematic 5 to 11 No Unspecified cycles Honda AVTEC Up to 13 No Fuel economy benefit compared to VTEC engine Hilite Univalve® Up to 15 Yes European NEDC cycle, w/o Individual Cylinder Lift ControlEnergy and Environmental Analysis, Inc. 1
‐ 17 The fuel economy benefit figur es are consistent among mo st developers. In fact, maximum figures reported by BMW, Nissan and Toyota are nearly identical and all include VVT contribution. Nissan specifically noted that VVEL contributes up to 12% fuel economy improvement compared to an i dentical engine without it. Honda’s AVTEC design, however, shows higher fuel ec onomy benefit and, more importantly, the comparison is against already very effici ent VTEC engines, which include the two-step VVL and VVT. Honda did report that the new engines will be completely retuned with redesigned ECU (Engine Control Unit) and like ly other measures. Reported specific additional fuel efficiency im provements include idle speed reduction (1.7% fuel economy benefit).

Hilite’s UniValve® benefits we re derived from European testing, which can not be directly compared against the US FTP cycle conditions, so for purpose of this analysis the 15% fuel economy figure should be us ed for reference purposes only.

EEA has reported earlier that CVVL, when VVT contribution is subtracted, yields about 8% fuel economy benefit. Additional informa tion obtained does dem onstrate that this figure is defensible (at constant performanc e) and should continue being used. In fact, the estimate appears to be on conservati ve side since Honda’s AVTEC solution appears to yield higher benefit, if other advantages of fully flexible valve lift and timing control, such as idle speed reduc tion, are more fully implemented.

Table 2-4 provides cost estimates (converted to RPE) for CVVL der ived from figures rin the EEA 2006 report .

Table 1-4. RPE [$] Estimates for Int ake-CVVL, by Engine Configuration.
I4 I6 V6 V8 CVVLT 330 400 460 600 Intake Phaser 52 52 104 104 CVVL (CVVLT minus Intake VVT) 278 348 356 496Energy and Environmental Analysis 1
‐ 18 New cost information obtained from Bosch (s ee Figure 2-4) indicates that BMW’s
Valvetronic adds about 20% to the cost of the base engine. Assuming a basic I4 (PFI, fixed valve timing) cost of $1,100 this figur e translates to about $220 incremental cost for CVVLT ($RPE about 370). When cost for a single VV T phaser is subtracted, CVVL results in about 320$RPE increase.

Using the same 20% increment, the CVVL RPE can be calculated to be about $430 for a V6 and $560 for a V8 (against base engine costs of $1,600 and $2,000 for a V6 and V8, respectively). These estimates are withi n the range of EEA’s earlier figures. More importantly, new systems announc ed by the above OEMs will result in more suppliers entering the market and additional savings fr om economies of scale. As a result, our
earlier RPE estimates for C VVL are still appropriate.


## 1.4 Camless Valve Actuation
Engine developers have long been interested in Camless Valve Actuation (CVA) since it promises as much as 20% improved fuel economy over conventional mechanically operated valves. There is less assembly co mplexity, engine friction and weight with camless design because mechanical camsha fts and related parts are eliminated. Camless valves would eliminate the conven tional throttle and, as a result, reduce pumping losses. Also, the camless engine wit h independent valve control would be less dependent on fuel quality. The independent valve actuat ion would be able to control residual combustion gases (internal EGR), further reducing pumping losses. Also cylinder deactivation can be easily implemented on larger engines.
This section examines one CVA design by Valeo, which was recently described in the
literature and is claimed to be close to ma rket introduction. The updated fuel economy and cost analysis is provided at the end.

1.4.1 Valeo Camless Smart Valve Actuation - SVA

Valeo has made numerous announcements t hat their SVA technology will be commercialized in less than 5 years, fo r production starting as early as 2009. 15Energy and Environmental Analysis, Inc. 1
‐ 19 In Valeo’s electromagnetic camless engine de sign, each valve is operated individually by an actuator that is plac ed on the upper surface of the cy linder head, directly above the valve guides. Each actuator is lin ked to an engine-mounted Valve Control Unit (VCU) that performs the power dr ive function (see Figure 2-10).

Figure 1-10. Valeo Electromagnetic CVA Design.

Valeo is developing two diffe rent systems, each one including: the actuators, the Valve Control Unit (VCU), the wiri ng rail and the Electronic C ontrol Unit (ECU) with the specific strategies dedicated to these new concepts. The first one is called "full camless" as it manages the valves on both the intake and exhaust side of the engine. The second one is called "half camless" as it manages the inlet valves only. 16

Valeo’s current plan is to commercialize the half-camless SVA, which would achieve
around 80% of the benefit s of a fully camless engine, at half the cost. Valeo announced that the incremental manufacturing cost for a four-cylinder, half-camless gasoline engine would be about $400.Energy and Environmental Analysis 1
‐ 20 Valeo confirmed that the main source of fuel economy improvement in the camless engine is the increase of the engine the rmodynamic cycle efficiency due to pumping loss reduction and combustion efficiency improvement (through Miller cycle or increased expansion stroke cycle). 17 Also some benefit can be realized through idle speed reduction. Valeo claims that t he half-camless engine would improve fuel consumption by about 12% (implying 14% fuel economy gain) and provide 15 to 20% more low-end torque than a conventional ga soline fixed valve timing engine. When cylinder deactivation benefit is included (imply ing that the exhaust valves must have a separate deactivation mechanism), the total efficiency gain can reach 17% (20% fuel economy). These figures were derived under laboratory test conditions. Valeo did confirm this data on a test vehicle equi pped with 2L I4 under European NEDC cycle
conditions. The vehicle tests showed that when a transmission is optimized for the camless engine operation, the fuel consum ption benefit can reach 19% (23% fuel economy). Figure 2-11 summarizes these conclusi ons. Note that the engine is also able to reduce criteria pollutant s dramatically, especially NO x and CO, primarily through internal EGR control and fast catalyst warmup.

Figure 1-11. Valeo’s Camless Valve E ngine Fuel Consumption Benefits.Energy and Environmental Analysis, Inc. 1
‐ 21 1.4.2 Analysis for Ca mless Valve Actuation
Automakers have commented publicly that t hey are closely following developments for camless technology. Companies are concer ned, however, that CVA would be costly and have uncertain durability once the valve tr ain is not mechanically connected to the crankshaft. It appears that primary concerns are not necessarily fo r valve actuators but rather for control system long-term durability.

EEA has reported previously that camless in take engines are expected to improve fuel economy by about 13.6% (at constant engine si ze), when compared to conventional PFI engines with fixed valve timing. Table 2-5 summarizes EEA’s earlie r estimates for CVA
costs.

Table 1-5. Camless Intake System- RPE Estimates.

I4 I6 V6 V8 Early Introduction Cost (~2012) [$RPE] 500 700 700 900 Long term cost (>2015) [$RPE] 350 500 500 630

The cost estimate, when converted to RP E, for Valeo’s system is about $650 which appears to be higher than the EEA short-term estimate for a 4-cylinder engine. As a result, EEA believes that Table 2-5 costs should be increased by 30% for both short and long term costs.

CVA should deliver at least the same benefit s as the CVVLT – or at least 12%, as
described in the CVVL section. Additional benefit would lik ely be realized on larger engines, when cylinder-cut is implemented. Further additional benefits for all engines can likely be realized if additional fuel econo my improvements are fully derived from advanced controls working with fully flexible intake valve actuation, as illustrated by Honda’s AVTEC announcements.

Valeo’s announcements indicate that autom akers are interested in the technology, which implies that additional fuel ec onomy benefits are proj ected from CVAEnergy and Environmental Analysis 1
‐ 22 implementation. As a result, EEA believes that 13.6% fuel economy improvement for CVA is a conservative estimate and could be revised to a higher value. Valeo’s latest reported improvement of up to 20%, at constant engine si ze, appears to be a high end value for intake-only CVA fuel economy benefi t compared to conventional non-variable
valve trains. As other manufacturers are expected to report data on this technology (Honda recently unveiled a prototype camle ss engine in Japan), the EEA value could be revised upwards to about 15%.



## 1.5 Direct Injection SI Technology
The Direct Injection Spark Ignition (DISI) engines can be differentiated into the stoichiometric homogeneous combustion and l ean stratified mixture combustion types.

The stoichiometric DISI process forms a homogenous mixt ure by injecting fuel into the cylinder during the intake stroke and controls the fuel/air ratio in the same way as conventional PFI (Port Fuel Injection) engine s. These types of engines typically achieve some fuel consumption impr ovements, among other effects, due to intake air cooling caused by fuel vaporization directly in the cylinder and the resulting opportunity to increase compression ratio. The emissions are controlled by a conventional 3-way catalyst.

The 1 st generation lean burn DISI engines achieved mixture formation through a special combustion chamber design and ar e referred to as “wall-guided”. In this type of engine the fuel spray injected into the cylinder is guided along the piston cavity wall to form a stratified mixture around the sparkp lug. With this design, a f uel film inevitably forms on the wall. The result is typically higher PM and HC emissions, degraded fuel consumption, flame quenching and poor combustion at certain conditions. 18 Another wall guided DISI disadvantage is that the stratified combustion is achieved with a wide spacing between the injector and spark plug. As combustion timing was difficult to control in these engines, ideal efficiency of the thermodynamic process could not be consistently attained.Energy and Environmental Analysis, Inc. 1
‐ 23 The latest generation lean burn DISI systems atte mpt to avoid the above limitations through mixture formation by the spray form of centrally mounted in jector, and therefore, are called “spray guided”. This process allo ws small spacing between the injector and the electrode. Also, the air-fuel mixture formation takes plac e independently of gas flow and piston movement. This offers an optimum option for raising the fuel economy of gasoline engines. Stratified lean combustion has high costs due to complexity of the after-treatment process. In the US market, shifting spray-guided operation toward
stoichiometric combustion has offe red a solution to this problem. 19

DISI systems combine well with turbo- charging. Conventional PFI turbocharged gasoline engines are popular in sports m odels, and offer excellent nominal power and torque outputs. However, these engines oft en do not offer increased fuel economy, are
difficult to control for emissions and tur bo lag. Many programs have demonstrated that these disadvantages can be overcome using DISI. These engines are believed to have significant potential to deliver high fuel economy, emission and performance simultaneously. 20, 21

1.5.1 Natural Aspirated Stoi chiometric DISI Engines Stoichiometric natural aspirated DISI engi nes are being used by few OEMs in the US. Toyota has introduced this technology in t he dual injection 3.5L V6 and 4.6L V8 engines used in the Lexus offerings. Volkswagen and Audi are configuring more of their vehicles to adopt the technology under the FSI (Fuel Stratified Injection) family name.

Toyota has adopted a very sophisticated injecti on strategy that involves both PFI and DI injector fueling depending on v ehicle operation (see Figure 2- 12). The result is a system that achieves very high therma l efficiency (as high as 0.36) in the core mid-to-high load range, which translates into high pow er at a reasonable fueling rate.Energy and Environmental Analysis 1
‐ 24 Figure 1-12. Toyota 3.5L V6 Dual Inj ection Engine Combustion Chamber Cutaway and Engine Map. 22

The 4.6L V8 was installed on the flagshi p Lexus LS460. Together with DI, the new engine features new VVT, friction reduction and other improvements. The engine displacement was increased by about 7% co mpared to the previ ous generation LS430 but the new technology was more than enough to compensate for fuel economy penalty resulting from additional displacement and pow er increase. The final result for LS460 is the US combined fuel economy of about 25. 3mpg. Figure 2-13 deta ils the performance and relative fuel economy improvement cont ribution of various engine technologies. 23 The total engine improvement is 7.5%, of wh ich about one-third (or ~3%) is DI benefits – compression ratio increase and combustion improvements.Energy and Environmental Analysis, Inc. 1
‐ 25 Figure 1-13. LS 460 and LS430 Fuel Ec onomy Comparison. Contribution of Various Engine Technologies.

Figure 2-14 further compares the fuel cons umption improvement of the new engine on LS460 versus previous generation 4.3L V8. F uel efficiency improvements of 6 to 8%
are available in the mid load area around 800 to 1,500 RPM, as well as at the top load area. The map also shows that the new engine was optimized to work with the 8-Speed AT, to achieve optimized torque and fuel consumption performance.Energy and Environmental Analysis 1
‐ 26

Figure 1-14. Toyota New 4.6L V8 Fuel C onsumption Comparison to previous 4.3L

GM has announced that its DI technology will be extended into V6 engines with first application in 3.6L on MY 2007 Cadillac CTS. Further applications are scheduled for
near future. 24

The new engine utilized most DI-related performance advantages for higher power rating (up 15%) compared to the previous generat ion, but also provides 3% better fuel economy. The 2007 CTS with its 255-hp, 3.6-liter V-6 is ra ted at 18 mpg city and 27 mpg highway (EPA adjusted), which is the same fuel economy as for smaller 2.8L V6,
also available on this vehicle.

GM’s 3.6L V6 features dual VVT, which helps reduce exhaus t emissions by optimizing exhaust valve overlap and eliminating the need for a separate exhaust gas recirculation (EGR) system. The injection system operates at 120bar, with lower 35bar used at idle conditions. Because of the DI cooling e ffect, the engine comp ression ration was
increased to 11.3.Energy and Environmental Analysis, Inc. 1
‐ 27 1.5.2 Turbocharged Stoichiometric DISI Engines
GM is now using a smaller derivative of the Ecotec, 2L I4 SIDI Tu rbo, in the MY 2007 Pontiac Solstice GXP (first turbo DISI for GM in North America) and Saturn Sky Red
Line. 25 The engine runs stoichiometric and also features dual VVT. It is tuned to produce minimal turbo lag with the use of dual-stroll turbocharger and aggressive valve overlap to enhance intake air scavenging for exhaust gases. The result of these and other refinements is that the engine develop s 260lb-ft torque (a 36% improvement over
the MPFI turbo version of the engine) over broad r ange from 2,500 to 5,250 rpm. Despite the large increase in power and torque, the engine maintains the fuel consumption of a small disp lacement port injected engine.

GM has recently reported new estimates concerning the fuel economy improvement potential from turbocharged engines under constant performance conditions. Figure 2- 15 summarizes the results of this study. GM’s simulation maintains the baseline vehicle (Chevy Equinox with 2.4 natural aspirated PFI) performance and shows that the add-on WG (Waste Gated) turbochar ger, SIDI and dual VVT can impr ove fuel consumption on FTP cycle by up to 10% relative to an engine with VVT. Up to 20% is possible if this technology is combined with the super charger and mild hybridization.

Figure 1-15. Fuel Consumption Reducti on for Various Boosting Options vs. Relative Cost IncreasesEnergy and Environmental Analysis 1
‐ 28 Ford already has several direct-injection f our-cylinder engines on the market in Europe. Mazda markets the 2.3L turbocharged engine in the US on Mazdaspeed6. The de-rated power version of the engine with smaller turbocharger is also used on the CX-7 crossover to provide increased fuel economy. 26

Ford has launched the new engine family in t he US, called Twin Force, which combines direct injection with turbo-charging. 27 The 3.5L V6 version was unveiled on the Lincoln MKR concept, an E85-capable model. The engine is claimed to perform comparably to, or better than V-8 engines, delivering 415 hp ( 310 kW) and 400 lb-ft (542 Nm) of torque
on an E85 ethanol blend.

Ford argues that achieving this type of per formance from a V-8 would require an engine displacement of 6.0-liter or larger, nearly double the size of the 3.5L. As a result, the Lincoln MKR concept delivers 15% bette r fuel economy than a V-8 with similar performance. Ford has indicated that Turbo DISI is likely on ultra-fuel efficient future compact cars, such as the Focus. At fi rst, the company wa s thought to bring a European diesel for this platform but the latest information suggests that diesels will be reserved for light trucks such as F150, wh ile downsized Turbo-GDI will be the preferred alternative for cars with upgraded performance and better fuel economy. 28

VW/Audi is known in the US for its direct injection turbo technology based on FSI (Fuel Stratified Injection), which is configured to run in stoichiometric mode and marketed on wide variety of engines, especially in Eu rope. VW announced that the FSI technology was used to develop the next generation down sized gasoline engine family, called TSI (Torque Strong Twincharger). Th e first products of the family, commercialized in Europe on the Golf platform, were 1.4L 125kW and 103kW I4 high performance engines with dual charging (supercharger and turbocharger).

In order to trade the perform ance for fuel efficiency and dec rease the engine costs, VW developed a single turbocharger derivativ e of the TSI engine, a 1.4L 90kW I4. 29 Figure 2-16 provides a pictorial representation of the TSI family development sequence on performance versus relative f uel consumption (equivalent to CO2 reduction) scale. TheEnergy and Environmental Analysis, Inc. 1
‐ 29 new 1.4L 90kW TSI provides the same perform ance as a 30% larger 4V FSI (2L natural aspirated I4), while providing about 22% impr ovement in fuel consumption (figure based on new Golf equipped with 1.4L TDI and 7-Speed dual clutch transmission compared to previous generation Golf – NEDC cycle, at constant vehicle size).

Figure 1-16. VW TSI Engine Relative Performance and Fuel Consumption (CO2 Reduction).

Direct injection, VVT and intercooled tur bo-charging plus downsizing were the main
contributors to the fuel e fficiency improvement. Further engine improvements include a simplified injection system and an optimized turbocharger. The intake manifold was simplified to eliminate the tumble flaps, wh ich reduced complexity and costs but still was able to achieve good charge mixing.

When the new 1.4L TSI is compared to 1.6L 85kW FSI, the torque performance results are remarkable, with peak torque available across a range from 1,500 to 3,500 rpm (see Figure 2-17).Energy and Environmental Analysis 1
‐ 30

Figure 1-17. VW New 1.4L Downsized TSI Engine Performance Compared to 1.6L FSI.

Audi has also recently demonstrated that downsized turbocharged DISI engines are capable of significant perform ance improvements. The com pany started marketing the technology with the 2L TFSI introduction and also recently introduced a brand new I4 1.8L TFSI engine (used in the European Audi A3). 30

Figure 2-18 compares Audi A3 performance and fuel consum ption with different engine options. The new 1.8L TFSI improves fuel consumption by 10% when compared to the same size Turbo PFI engine, while o ffering a 7% increase in rated power.Energy and Environmental Analysis, Inc. 1
‐ 31 Figure 1-18. Audi A3 Acceleration (80 to 120 km/h) and Fuel Consumption Comparison among Different Engine Options (European Data). 1.5.3 FEV Turbo DI, VCR, Flex Fuel Engine Concept FEV Engine Technology has showcased a de velopmental gasoline/E85 turbocharged direct injection (GTDI) engine that also features variable compression ratio (VCR) at the 2007 SAE World Congress. FEV claims that, while offering the potential to generate V-8 power from a V-6 engine, this concept also provides roughly a 20-25% improvement in fuel consumption.

The system achieves variable compression using an eccentric crankshaft bearing. Rotation of the eccentric bearing leads to a vertical position change of the crank train relative to the cylinder head and thus, a conti nuous change in the compression ratio. An electric motor controls the adjustment between compression ratios of 8 and 16.

The VCR engine offers an opportunity to ta ke advantage of the higher octane rating available from ethanol fuel by increasing t he compression ratio for higher-level ethanol blends. Figure 2-19 shows the VCR mechani sm and itemizes the estimated fuel economy contributions from various technologies. 31 According to FEV, DI can increaseEnergy and Environmental Analysis 1
‐ 32 fuel economy of natural aspi rated engines by up to 8%. The stratified DI can improve fuel economy by up to 18% and Turbo-DISI – by 22%.

Figure 1-19. FEV VCR Mechanism and Pote ntial Fuel Economy Contributions from Various Technologies. Although the three principal elements of the engine—VCR, GTDI and Turbocharging— have been tested on the bench and on the road, FEV has not yet put all three together
in a vehicle. FEV disclosed that the conc ept is only a demonstration tool intended to show that gasoline engines are able to reach diesel-like efficiencies.
1.5.4 Spray Guided DISI Lean- Burn Engines BMW has publicly stated that the DI stratified combus tion provides the greatest individual technology step for reducing fuel consumption in SI engines. The company chose not to adopt the 1 st generation wall-guided DI sinc e its fuel consumption advantages were estimated to be comparabl e to BMW’s Valvetr onic CVVLT system. However, BMW indicated that the new gen eration spray-guided DI system eliminates the disadvantages of the wall-guided syst ems, and the company is aggressively pursuing it. 32Energy and Environmental Analysis, Inc. 1
‐ 33 BMW first launched the technology, dubbed “ High Precision Injection and Stratified Combustion – HPI”, on 3L I6 twin-turbo engine in the MY 2007 335i sedan. The engine is configured with two turbo-chargers, eac h charging 3 cylinders, which significantly reduces turbo lag issues and improves fuel consumption. Each turbo is smaller and lighter and has a lower moment of inertia, which allows much faster pressure buildup compared to engines with larger single turbo. 33

The piezo injection system operates at pr essures up to 200bar. The injectors permit up to 3 injections per cycle, providing high flexib ility for the calibration strategy to supply a very efficient combustion with low emissions . The injection system alone improved fuel consumption by 2-3% and emi ssions by 20%, according to BMW. Figure 2-20 provides a cutaway view of the new combustion chamber design. Note the injector placed in central vertical position with the ti p next to the sparkplug electrode.

Figure 1-20: BMW Spray Guided Stratifi ed HPI Combustion Chamber Cutaway.Energy and Environmental Analysis 1
‐ 34 The new engine does not inco rporate the Valvetronic s ystem but retains 24-valve DOHC cylinder head. The engine tuned for pe rformance on 335i is able to provide about 15% performance gain (as measured by 0-100km/h acceleration), which would be equivalent to naturally aspirated V8 engine of about 4L displacement (see Figure 2-22). BMW has indicated that the HPI optimized fo r fuel efficiency can achieve a 15 to 20% fuel consumption gain, compar ed to the Valvetronic versi on of the engine, while still providing 5% performance improvement.

Figure 1-21. Fuel Consumption and Perf ormance of BMW 335i Compared to Competition (Data is based on European Testing) Because of sringent NOx emissions requi rements in the US, BMW configured the system to run in overall hom ogeneous mode except during the engine/catalyst warm-up periods where the stratified charge is impl emented. The same engine is available in Europe as a lean-burn stratified charge engi ne. BMW is expanding the HPI technology into naturally aspired engines, including si x- and four-cylinder configurations in Europe. 34 The new 2.0L I4, is scheduled for the 1- Series, and the 3L I6 HPI version forEnergy and Environmental Analysis, Inc. 1
‐ 35 the 5-Series. The engines do retain the dual VVT and variable inta ke manifold. The exhaust emissions control incorporat es the NOx storage catalyst.

Compared to wall-guided stra tified DI, the spray-guided syst em permits a significant expansion of the stratified mode on the engine map (see Figure 2-22). The engine controller maintains the highly stratified in jection mode up to about 4,200RPM and up to about 0.5kJ/l specific effective work per formed. The stratified envelope is wide enough to provide for acceleration of the vehicle up to 160km/h.

Figure 1-22. BMW New 3L I6 HPI Engine Map, Fuel Consumption and Operating Modes.
Figure 2-23 summarizes the fuel consumpt ion and performance of the new engines installed on 1- and 5- Series compared to the predecessors with Valvetronic. The new engines reduce fuel consumption on avera ge by 14% and increase power by about
13%.Energy and Environmental Analysis 1
‐ 36

Figure 1-23. Driving performance and fu el consumption for BMW 530i and BMW 120i with new I6 and I4 engines.

Mercedes launched its version of spray-guid ed DISI technology (see Figure 2-24) on 3.5L V6 engine in MY 2007 CLS350, which is available in Europe. The new engine improves fuel consumption by 10% compared to previous version of the V6 under the NEDC cycle conditions, while improvi ng power by about 7% and torque 4%. 35Energy and Environmental Analysis, Inc. 1
‐ 37 Figure 1-24. Mercedes Spray-Guided DISI Combustion Chamber Design
The engine features rapid response 200bar piezo injectors and controller by Bosch, which opens the nozzle tip outward forming a hollow cone spray pattern. 36 The injection system can produce multiple injections per cycle which improves the lean burn combustion efficiency and reduces noise. The piston bowl was redesigned for this process to concentrate the lean mixture in the spark plug area and minimize mixture spreading toward outer cylinder walls.

The engine improvements allo wed the lean-burn stratified mode expansion to medium loads. Mercedes has shown that at very light loads up to 40% fuel consumption improvement is possible with the stratifi ed DISI, although the map window is very narrow (see Figure 2-25). As loads increas e toward mid-range, fuel consumption improvement of 10 to 20% is expected. Overall, the stra tified lean burn window is wide enough to accelerate the vehicle to speeds of 150km/h. At higher loads the system is designed to revert back to stoichiometric mode, at which up to 2% fuel consumption improvement is still expected.Energy and Environmental Analysis 1
‐ 38 Figure 1-25. Mercedes Stratified Ch arge Region Map and Fuel Consumption Reduction Potential as Compared to PFI
The NOx control of the engine is accomplis hed through high EGR rates (up to 40%) and two under-floor LNT (by Umicore – see Fi gure 2-26). Umicore believes that LNT technology is a generally preferrable way to control NOx in lean burn DISI engines. 37

Figure 1-26. Mercedes CLS350 CGI Exhaust System ConfigurationEnergy and Environmental Analysis, Inc. 1
‐ 39 1.5.5 Direct Injection Summary and Analysis
The above discussion provides overwhelming evidence that new generation DISI is capable to provide a wide range of fuel ec onomy advantages. Stoichiometric DISI is already being adopted with incr emental fuel economy benefits. Turbo DISI offers an opportunity for very large performance incr ease (at constant displacement) or substantial fuel economy gai n (downsized engines). Lean bur n DISI has reached the 2 nd generation and can achieve very large fuel economy gains, although the aftertreatment incremental costs are limiting the technology growth, especially in the US market.

Table 2-6 summarizes EEA’s earlier estima tes for fuel economy gains and costs for various DISI technologies.

Table 1-6. EEA Estimates for Fuel Econom y Benefits and Cost s for Various DISI Technologies. All estimates relative to PFI engine with fixed valve timing $RPE by Engine Configuration Technology FE Gain [%] I4 I6 V6 V8 Stoich. DI 3.5 (const. engine size) 120 155 155 210
Lean Burn DI 12 (const. engine size) 830 (with aftertreatment) Turbo -1 (const. engine size) 500 560 580 660 Turbo 7 (engine downsized) N/A -200 (I6 replaced by I4) -200 (V6 Replaced by I4) -220 (V8 replaced by V6) Turbo Stoich. DI 12 to 14 (engine downsized) 625 ~0 (V6 is replaced by I4) ~0 (V8 replaced by V6)

Figure 2-27 summarizes equivalent technol ogies and their potential benefits from BMW’s perspective. Using 4-Valve fixed timi ng/lift PFI engine as the base, the add-on stoichiometric DISI (DI λ =1) yields about 5% fuel cons umption gain (5% fuel economy) with modest power increase (on specific power basis). If th e spray-guided DISI is used ( λ >>1) largely for fuel economy gain, the benefit can reach 20% (25% fuel economy). IfEnergy and Environmental Analysis 1
‐ 40 turbocharged DISI is used wit hout engine downsizing, the engine can maintain fuel economy of natural aspirated PFI and the power increase is as high as 50%. BMW’s lean burn spray-guided DISI turbocharged technology yields up to 18% fuel consumption gain (22% fuel economy) while providing 50% power boost at the same
time.

Figure 1-27. BMW Estimates for SI Engine Specific Po wer and Fuel Consumption Reduction Benefits for Various Advanced Technologies.

Renault has published results of their study, which indicates that engine downsizing with turbo-charging can be more cost effective for fuel economy improvement in certain vehicle classes, especially compacts, and more attractive t han standalone lean-burn DI or micro hybridization (see Figure 2-1). Furthermore, the DI Turbo technology fuel economy benefits are realized in a wide ran ge of operating conditions. Renault has shown that stoichiometric DISI yields about 5% fuel economy gain at constant engine size. An estimate for the downsized DISI (sto ichiometric) is 17 to 20% fuel consumption improvement, which converts to a 21 to 25% fuel economy gain on the NEDC cycle.

AVL has shown similar result s, obtained using computer models. The company used VW’s 2L FSI non-turbo engine as the basis for the simulation. Results showed that the engine downsizing to 1.4L combined with tur bo-charging yields about 11.3% fuelEnergy and Environmental Analysis, Inc. 1
‐ 41 consumption improvement (13% fuel economy). Adding other technologies, such as downspeeding (engine torque map shift toward lower RPMs and corresponding transmission and axle ratio rebalancing) and cooled EGR can yield about 25% total improvement (33% fuel economy). Figure 2-28 summarizes these results.

Figure 1-28. Fuel Consumption (CO2) Re duction Potential for Various Engine Technologies.
Source: AVL

Audi has shown that even larger fuel cons umption improvements ar e possible from next generation turbocharged DI engines. Figur e 2-29 shows fuel consumption and performance progression for Audi’s benchm ark 2L TFSI used on the A4. When the current technology is compared to future 3 rd generation expected fuel consumption, the engine yields about 25% fuel consumption improvement together with performance
enhancements. This translates to 33% addi tional fuel economy improvement over Audi’s current TFSI. While deta ils of such large gain are not clear, it is likely the leanburn DISI is necessary together with other drive train improvements.Energy and Environmental Analysis 1
‐ 42 Figure 1-29. Audi 2L TFSI Fuel Cons umption and Performance Progression. 38

Table 2-7 summarizes fuel economy improvem ent estimates as reported by various
sources above. EEA’s recommended f uel economy improvements for these technologies are also provided.

The benefit for turbocharged and dow nsized DISI engines could be increased slightly as a result of new data available from GM and Ford but these estimates are within the range we reported earlier, so that the 14 % FE benefit is appropriate.

EEA recommends that other estimates from earlier analysis should be kept and are defensible and perhaps conservative. Eur opean engine developers have reported very high fuel economy gains for various turbo/DI packages. However, because the data is derived against European test cycles, these estimates should be used for reference purposes only.Energy and Environmental Analysis, Inc. 1
‐ 43 Table 1-7. Summary Fuel Economy Gain Es timates for Various DISI Technologies and EEA New Recommendations. Compared to PFI natural aspirated engine, unless ot herwise noted. “Constant performance” condition due to engine downsizing can include marginal performance improvement. Technology Fuel Economy Gain by Source [%] Condition EEA Recommended Fuel Economy Gain [%] Condition

Lexus 2.5 Compared to 7% Smaller Engine GM 3 Const. Displacement BMW 5 Const. Displacement Renault 5 Const. Displacement Stoich. DI

FEV Up to 8 Const. Performance 3.5 Constant Displacement

BMW 18 to 25 Downsized Engine, compared to Valvetronic Constant Displacement Mercedes 11 Constant Displacement Lean Burn DI

FEV Up to 18 Const. performance 18

GM 4 to 9 Const. performance -1 Constant Displacement Turbo

AVL 13 Const. performance, against base with DI 7 Constant Performance GM Up to 15 Const. performance, includes DVVT Constant Performance Ford 15 Const. performance VW 28 Const. performance, with double-clutch transm. NEDC cycle
FEV 22 Const. performance Turbo Stoich. DI

Renault 21 to 25 Const. performance 14

NEDC cycle

Concerning add on system costs, EEA obtained new estimates from Bosch (see Figure 2-4). Table 2-8 below itemizes the Bo sch costs and conditions under which the
estimates were determined.
Table 1-8. Technology Cost Estimates Derived from Bosch Data. All estimates relative to PFI engine with fixed valv e timing, unless noted. All estimates at constant displacement. Base engine costs: $1,100-I4, $1,600 -I6, $1,600-V6, $2,000-V8;$RPE/$Cost Ratio – 1.7 $RPE by Engine Configuration Technology I4 I6 V6 V8 Stoich. DI 240 350 350 430 Lean Burn DI (with aftertreatment) 820 1,200 1,200 1,500

Turbo 440 640 640 800 Turbo Stoich. DI with DVVT 770 1,120 1,120 1,400
Turbo DI with engine downsize 700 370(I-6 replaced by I-4) 370 (I-6 replaced by I-4) 600 (V-8 replaced by V-6)Energy and Environmental Analysis 1
‐ 44 

## 1.6 References for Section 2

1 Energy and Environmental Analysis, Inc. , “Technologies to Impr ove the Fuel Economy of Light Duty Trucks to 2015”, Report Prepared for the US Departm ent of Energy and the US Department of Tr ansportation, May 2006.

2 Y. Boccadoro, L. Kermanac’h, et al., “The New Renault TCE 1.2L Turbocharged Gasoline Engine”, Vienna Moto r Symposium, April 2007.

3 Dr. Klaus Eggerr, “Electronics and Mechat ronics Increase Fuel Economy”, Aachen Colloquium, Automobile and Engine Technology, October 2006.

4 U. D. Grebe, I. Larsso n, “Comparison of Charging Systems for Spark Ignition Engines”, Vienna Motor Sy mposium, April 2007.

5 Presentation to EEA Duri ng Company Visit in 2007.

6 T. Arinaga, M. Kobayashi, et al., “A Study of Friction Ch aracteristics of Continuously Variable Valve Event and Lift (VEL) Syst em”, SAE Technica l Paper 2006-01-0222.

7 Nissan Press Release, “NISSAN INTRODUCES INNOVATIVE ENGINE VALVE
CONTROL TECHNOLOGY - Variable Valve Event & Lift (VVEL) delivers significant improvements in dynamic and environm ental performance”, March 29, 2007.

8 Toyota Press Release, “Toyota Develops Next-generation Engine Valve Mechanism”, June 12, 2007.

9 “Statement of John Germ an, Manager, Environmental and Energy Analysis, Product Regulatory Office, American Honda Moto r Company, Inc.”, Before the Senate Committee on Energy and Natural Resour ces, U.S. Senate, January 30, 2007.

10 Fujii, et al., “Variable Valve Actuati ng Device”, United States Patent Number 6,968,819, November 29, 2005.

11 H. Tagami, Y. Yasui, M. Sato, H. Ito, “Management System for Continuously Variable Valve Lift Gasoline Engine”, SAE Technical Paper 2007-01-1200.

12 R. Flierl, D. Gollasch, A. Knecht, W. Hannibal, “Impro vements to a Four Cylinder Gasoline Engine Through the Fully Variable Va lve Lift and Timing System UniValve®”, SAE Technical Paper 2006-01-0223.Energy and Environmental Analysis, Inc. 1
‐ 45 13 Hilite International, “UniValve®, Fully Vari able Mechanical Valve Train for Engines”,
Information Brochure.

14 M. B. Riley, D.W. Fiddes, “A Fully Vari able Mechanical Valvetrain with a Simple Moving Pivot”, SAE Tec hnical Paper 2005-01-0770.

15 AutoWeek, “Valeo Signs up “Several Gl obal Automakers” for Camless Engine”, December 18, 2006.

16 Valeo Technology Description, “Smart Va lve Actuation Technology: the Camless Engine Becomes a Reality”. Available on the web at: http://www.valeo.com/automotivesupplier/Jahia/lang/en/pid/1317

. 17 D. Durrieu, V. Picron, et al., “Electromagnetic Valve Ac tuation System: First Steps Toward Mass Production”, Variable Valve Co ntrol Congress, October 2007, Essen.

18 H. Katashiba, T. Honda, et al., “Improvement of Center Injection Spray Guided DISI Performance”, SAE Tec hnical Paper 2006-01-1001.

19 H. Toduka, T. Yoshinaga, et al., “Flexibl e Design of Fuel Injection and Ignition Systems for Gasoline Direct Inject ion Engines”, Vienna Symposium 2006.

20 W. Bandel, G. Fraidl, et al., “The Tur bocharged GDI Engine: Boosted Synergies for High Fuel Economy Plus Ultra-Low Emissi ons”, SAE Technica l Paper 2006-01-1266.

21 G.K. Fraidl, P.E. Kapus, et al., “GDI Turbo: The Next Steps”, Vienna Motor Symposium, April 2007.

22 T. Ueda, Toyota Motor Co rporation, “Innovative Deve lopment Methodology Based on the Toyota Way”, Vienna Moto r Symposium, April 2007.

23 T. Asahi, T. Yamada, H, Hashizume, “The New 4.6L V8 SI Engine for the Lexus LS460”, Vienna Motor Symposium, April 2007.

24 R. Truett, “New Caddy Gets GM’s Most Muscular V-6”, Automotive News, March 26,
2007.

25 SAE International Magazine, “Lag Reduc ed with GM 2.0-L Tur bo”, Article, January
2007 Issue.

26 SAE International Magazine, “Mazda Expands DISI Turbo to Ad ditional Models”, February 2007 Issue.Energy and Environmental Analysis 1
‐ 46 27 Ford Media, “Lincoln MKR Concept Featur es New Design Direction”, Available on the
Web at http://media.ford.com/products/ presskit_print.cfm?vehicle_id=1528

28 R. Truett, “Ford Won’t Offer Diesels in NA Cars”, Automotive News, January 8, 2007.

29 R. Szengel, H. Middendorf, et al., “The TSI with 90kW – the Expansion of the Volkswagen Family of Fuel-efficient Gaso line Engines”, Paper Presented at Vienna Symposium 2007.

30 J. Bohme, W. Hatz, et al., “The New R4 – 1.8L TFSI Engine From Audi”, Aachen Colloquium, Automobile and Engine Technology, October 2006.

31 Publication Media Distri buted by FEV at SAE World Congress – 2007, Detroit, Michigan.

32 A. Welter, H. Unger, et al., “The New Turbocharged BMW Six Cylinder Inline Petrol Engine”, Aachen Colloquium, Automobile and Engine Technolog y, October 2006.

33 C. Luttermann, S. Missy, et al., “High Precision Inje ction in Combination with Turbocharger of the new BMW Twin Tur bo Petrol Engine”, Aachen Colloquium, Automobile and Engine Technology, October 2006.

34 P. Langen, T. Melcher, et al ., “New BMW Six- and Four-Cyl inder Petrol Engines with High Precision Injection and Stratified Comb ustion”, Vienna Motor Symposium, April
2007.

35 A. Waltner, G. V ent, et al., “The 2 nd Generation of Gasoline-Dir ect-Injection – Aspects of Exhaust Gas Aftertreatment and Cataly tic Converter Development”, Aachen Colloquium, Automobile and Engine Technology, October 2006.

36 Bosch Technology Description, “Premier e in the Mercedes-Benz CLS 350 CGI, Bosch Gasoline Direct Injection Makes its D ebut with Piezo Injectors”, Available on the
Web at http://www.bosch-presse.de/TBWebD B/en-US/PressText.cfm?id=2625

37 W. Mueller, S. Eckhoff, S. Philipp, Umicore, “NOx St orage Catalyst Systems for Spray-Guided Gasoline Direct Injection Engi nes”, AutoTechnology Magazine, February
2007 Issue.

38 M. Winterkorn, “The Drivetrain Strategies of a Global Company Facing International Competition”, Vienna Motor Symposium, April 2007.Energy and Environmental Analysis, Inc. 2
‐ 1 

# 2 ADVANCED TRANSMISSIONS

2.1 Introduction

In both automatic and manual transmissions , increasing the number of gears can provide a wider ratio spread between the first and top gears, which allows the engine to operate closer to its efficient optimum at a wider variety of v ehicle speeds, thereby facilitating an increase in fuel economy. Five speed automatic transmissions are becoming standard equipment on many vehicles, while 6-s peed are in transition from luxury to mainstream cars and trucks.

Table 3-1 summarizes the MY 2005 market penetration data by transmission type and OEM. The automotive transmi ssion offerings were highly variable among different manufacturers. Honda, for example, offered 5-speed ATs on majority of their cars and trucks. GM, on the other hand, made the 5-speed availabl e only on selected models. Ford was the leader for 6-speed AT adoption in cars and trucks although the penetration was relatively low.

The manual transmissions in MY 2005 were gener ally offered by all OEMs, mostly in low-end compact cars and trucks. Honda and Nissan stand out with over 10% penetration in cars. Ford had substantial penetration of CVTs in both I4 engineequipped cars and trucks, while Nissan is uni que because it was the first OEM to use the CVT with high output engines (Murano 3.5L V6).Energy and Environmental Analysis 2
‐ 2 Table 2-1. MY 2005 Transmission Pe netration by Type and OEM. 4sp Auto 5sp Auto 6sp Auto 5sp Manual 6sp Manual CVT Light Duty Vehicle Penetration Daimler Chrysler 78.20% 15.70% 4.55% 1.53% Ford 59.07% 15.95% 10.37% 9.78% 4.82% GM 92.87% 5.77% 0.88% 0.49% Honda 23.63% 58.80% 13.23% 4.30% 0.05% Nissan 54.65% 33.62% 5.75% 5.98% Toyota 42.41% 46.83% 2.34% 7.65% 0.76% Light Duty Truck Penetration Daimler Chrysler 62.18% 34.45% 0.68% 2.69% Ford 78.98% 11.06% 0.90% 3.03% 6.03% GM 84.10% 14.96% 0.08% 0.85% Honda 8.77% 89.02% 2.21% Nissan 23.70% 56.10% 1.11% 2.94% 16.16% Toyota 18.02% 76.90% 2.92% 2.16% This section examines the most recent advanced transmission developments and fuel economy improvement announcem ents. EEA’s updated reccomendations for fuel economy benefits and costs for new tr ansmissions are also provided.


## 2.2 Automatic Transmissions
2.2.1 Mercedes 7G-Tronic, 7- Speed Automatic Transmission Mercedes has marketed their 7-speed AT, 7G-Tronic, since 2004. 1 The transmission was derived from a 5-speed AT design with the front single planetary gear set replaced by a Ravigneaux planetary gear set with add- on multi-disk brake. The seven speeds were achieved by using a total of three pl anetary gear sets, three clutches and four brakes (see Figure 3-1). The transmission is slightly larger than 5-speed but Mercedes was able to minimize the weight in crease by using a magnesium casing.Energy and Environmental Analysis, Inc. 2
‐ 3 Figure 2-1. Mercedes 7G-Tronic
The new transmission was first used by the Mercedes S-Class. Depending on the driving cycle, fuel consumption was r eported 6.1 to 10.9% lower (fuel economy improvement, 6.5 to 12.2%) when compared to 5-speed-equipped vehicle (see Figure 3-2). In addition to wider gear spread advant age, DaimlerChrysler reported that fuel efficiency was improved through improved lubricat ing fluid, reworked controller and shift schedule. The transmission was designed to enable gear skipping during rapid downshifting. The torque converter lockup wa s designed to be active in all forward
gears.Energy and Environmental Analysis 2
‐ 4 17
15.3

11.5 10.1 15.66 14.16

10.79
9.01

0 2 4 6 8 10 12 14 16 18

City Highway Ams-cycle Mot-CycleFuel Consumption [l/100km]

S500L 5-Speed AT S500L 7-Speed AT

Figure 2-2. Mercedes S500 Fuel Efficien cy Comparison, 7G-Tronic vs. 5AT. 2

2.2.2 Toyota/Aisin 8-Speed Automatic Transmission
Toyota/Aisin has developed a new 8-speed aut omatic transmission commercialized on the Lexus LS 460. 3, 4 The 8-speed was developed from Aisin’s 6-speed AT which is based on a Leppelletier gear set. In order to obtain 8 forward speeds the Leppelletier set was connected to a Ravigneaux gear train. The transmission is controlled using four multiple clutches, two multip le brakes and one one-way clutch.

The 8-speed fits in the older 6-speed pa ckaging space. The size performance was made possible by smaller co mponents, improved hydraulic circuit design with fewer parts and a more efficient geartrain.

The transmission controller was configured to pr ovide dual clutch-to-clutch shift control
in which two friction elements engage and two friction elements disengage simultaneously for quick and smooth response. The shift speed was improved by 41% compared to LS430 6-speed. The transmi ssion can skip two or more speeds on downshifts. The ratio spread is quite large, from the first gear’s 4.596:1 to eight’s 0.685:1, but eight ratios mean they are closely spaced. 5Energy and Environmental Analysis, Inc. 2
‐ 5 The transmission was designed to achieve f uel efficiency improvement through the following means: 6

Extended fuel cut under deceleration. During deceleration the controller can command a fuel cut from 5th through 8 th gears, including coast-down shift event.

Higher top gear ratio. Enabled reduction of engine RPMs during highway cruising, while the lower gears were optimized for various urban driving conditions.

Expansion of the neutral contro l operation range during idle. This is accomplished by transmission controller, which brings the turbine speed of the torque converter closer to the pump speed (up to 10% fuel econom y improvement is possible at idle).

Expanded lockup. Lockup and flex lock-up contro l system extended from the 4 th to the
8 th gears.

The result of these improvements is that the 8-speed AT used on Lexus LS460 improved fuel economy by 6.5% (US comb ined) compared to 6-speed on older LS (comparison at constant 4.6L V8). Also 0- 60km/hr acceleration improved by 2%, 100- 180km/hr by 4%. Figure 3-3 summarizes fact ors that contributed to fuel economy gain (note that the gear ratio spread increase contributed abo ut 40% of total gain).

Figure 2-3. Fuel Economy Improvement, Lexus LS, 8-speed vs. 6-speed.Energy and Environmental Analysis 2
‐ 6 2.2.3 ZF 8-Speed Automatic Transmission ZF announced development of new 8-Speed AT for passenger cars (see Figure 3-4). 7 The transmission features four pl anetary gear sets (not Lepelle tier though) and five shift elements (clutches). Only two shift elem ents are opened in each gear, which leads to considerably lower drag losses. The transmi ssion was also designed to have high total gear ratio spread and the torque conver ter was improved for quick lock-up. 8

Figure 2-4. ZF’s New 8-Speed Automatic Transmission.
As a result of increased gear ratio spread and additional improvements the new box is capable of up to 6% fuel efficiency improv ement (6% fuel economy gain), compared to the 2nd generation production 6-Speed AT from ZF. When compared to mainstream 5- speed ATs, ZF claims that their new 8- speed can achieve 14% fuel efficiency improvement (16% fuel economy). Figure 3-5 summarizes these claims.Energy and Environmental Analysis, Inc. 2
‐ 7 Figure 2-5. Fuel Efficiency Improvemen t for Various ZF Transmission Designs. 

## 2.3 Automated Manual Transmissions
Volkswagen has been marketing the 6- speed dual-clutch AMT (Automated Manual Transmission –DSG®) since 2003. The transm ission has an input torque capacity of 350 N-m, and is used in compact and mid-size vehicles, such as the Golf and Passat.

VW has announced that a brand new trans mission was developed for the DSG® AMT family, a 7-Speed AMT (see Figure 3-6). The tr ansmission has a torque capacity of 250 N-m, so it will be used in lower power ve rsions of the Golf/Passat but also in subcompacts such as the Polo. 9

In addition to a higher gear ratio spread, the new transmission featur es a ”dry” clutch design (hence the reduced torque capacity). The new clutch reduces internal losses substantially since the cool ing oil drag is eliminated. Other reported design benefits
include:

• Gear ratio change for better driv e-off performance and cruising;

• Decreased controller power consumption;

• Increased mechanical transmission efficiency.Energy and Environmental Analysis 2
‐ 8 Figure 2-6. Cross Section of New 7-speed AMT from VW.

The new 7-speed AMT achieved substantia l fuel efficiency improvement even compared to the already co mpetitive 6-speed AMT. Figur e 3-7 summarizes this data and compares various transmission designs against the 6-speed manual transmission baseline. The data shows that, under NE DC cycle conditions, the 6-speed AT fuel consumption is 5 to 15% higher when co mpared to 6-speed manual transmission. The 6-speed AMT fuel consumption performance is basically the same as the manual transmission, although under certain condit ions, the AMT can achieve 5% fuel consumption reduction but also up to 3% penalty can be realized. The new 7-speed AMT is claimed to have fuel consumption advantage across the board, 7 to 12% better than the 6-speed manual.Energy and Environmental Analysis, Inc. 2
‐ 9 Figure 2-7. Fuel Consumption Comparis on of Different Transmission Designs from VW. MQ250 - 6-speed Manual Transmission; AQ – 6-speed Automatic Transmission; DQ250- 6-speed AMT; DQ200 – 7-speed AMT.

Cost estimates for the new transmission are not publicly available but the fact that its application is targeted for subcompacts such as Polo suggest that the costs must be competitive with the older 6-speed AMT. By elim inating the clutch c ooling oil circuit, VW removed parts such as suction filter, oil c ooler and pressure lines. Also the dry clutch design allowed decreased transmission oil r equirements from 7 to 1.7L. The shift mechanism was simplified so that 7 speeds can be controlled with f our actuators. The
result of these modifications is that the 7-speed AMT weight decreased to 73kg (compared to 80kg for 6-speed AM T). Also transmission size was substantially reduced. 

## 2.4 Continuously Variable Transmissions
Continuously Variable Transmissions (CVT ) have been in mass production for many years and have reached mainstream stat us. About 2.5 million CVTs, mainly compression belt drive-type, have been produc ed in 2006 worldwide. Nissan, Toyota and DaimlerChrysler are leadi ng automakers that adopted t he technology on many
models.Energy and Environmental Analysis 2
‐ 10 The fuel economy performance for CVTs is generally competitive with manual transmissions. In some cases, up to 5% benefit has been demonstrated when compared to manual transmissions. 10 Compared to 4-speed automatic transmissions, up to 15% fuel economy benefit can be realized. 11

Bosch has shown that there is a lot of potent ial for further CVT technology improvement (see Figure 3-8) . Improvements can be derived from refined elec tronic controls that can minimize losses in the oil pump, torque c onverter, variator and drive/neutral/reverse unit. The company has shown that up to 7.5% additional fuel econ omy improvement is possible in FTP cycle with thes e strategies. Also, advanced CVTs would be well suited for mild hybridization, since electrical oi l pump would allow engine shutdown. With startstop technology implementation fuel economy improvement can further increase to
9.5%.

Figure 2-8. Bosch CVT T echnology Expected Fuel Efficiency Improvements.
Baseline for comparison is current CVT technology used in A-Class subcompact with 180N-m torque capacity 1.9L I4 engine. M- Measured Values; S- Simulation. 

## 2.5 Advanced Transmission Summary and Analysis

EEA’s earlier estimates for advanced tr ansmission fuel econom y improvements and costs (converted to $RPE) are summarized in Table 3-2. EEA has also documented that RPE increase for each additional gear is about $50.Energy and Environmental Analysis, Inc. 2
‐ 11 Table 2-2. EEA Earlier Estimates for Fuel Economy Benefits and RPE Increase, Compared to 4-Speed AT

Transmission Type Fuel Economy Benefit [%] $RPE

5-Speed AT 2.5 200

6-Speed AT 4.5 205

7-Speed AT 5.3 255

AMT 7.0 210

CVT (engines <2.8L)

CVT (engines >2.8L) 7.5

6.0 240

380
The new information suggests that the benfit for 7-speed and 8-speed transmissions should be higher than original ly estimated by EEA. Mercedes reported that lower-end fuel economy gain, 5-speed AT versus the 7G -Tronic, is about 6.5%. EEA’s information in Table 3-1 above indicates that 5-speed ve rsus 7-speed fuel economy gain is 2.8%, which is the benefit for a wider gear rati o spread and additional speeds, isolated from other possible transmission refinements. Mercedes fuel economy gain does include other transmission improvements, such as im proved lubricating oil, reworked controller and lockup schedule, etc.

Lexus information (see Figure 3-3) indicates t hat the gear ratio spr ead increase with two additional gears contributes about 40% of the total fuel economy gain. When Mercedes’ 6.5% figure is multiplied by 0. 4, the result is 2.6%, which is very consistent with EEA’s estimate of 2.8%. Therefore, the fuel economy benefits fo r gear increases from 5 to 7 speeds in Table 3.1 appears to not include further increases in ratio spread.

The 8-Speed AT fuel economy benefits are documented by To yota/Aisin. Once again, the gear ratio spread increase of two gears (8-speed versus 6-speed) contributed about 2.6% (0.4 x 6.5%) of fuel economy gain. Other fuel economy gains for Toyota’s design were associated with a new controller, which achieves additional fuel economy benefits at idling, a reworked torque converte r and an expanded fuel-cut envelope.Energy and Environmental Analysis 2
‐ 12 When EEA’s 6-speed versus 7-speed fuel ec onomy incremental benefit of 0.8% is subtracted, the 8-speed versus 7-speed the remaining benefit is 1.8%. EEA believes that this fuel economy figure is reasonable for the 8-speed’s incremental FE gain over a 7-speed. It also should be not ed that other transmission im provements could provide an
additional 1.5 to 2 % benefit over current transmissions.

ZF’s fuel consumption figures (see Figur e 3.5) for various transmissions were developed in Europe and generally provide mo re aggressive gains, especially 5-speed
versus 2 nd generation 6-speed AT. ZF data does not appear to be representative of the US test cycles but certainly supports argum ents that substantial fuel economy benefits can be obtained with fully optimized advanced transmissions with a wide gear ratio spread, as long as internal trans mission losses are properly managed.

VW’s information for AMT developments illus trates that 6-speed AMT provides a fuel consumption benefit of 2 to 10% when compared to 6-speed AT, although the data was developed in Europe and is highly dependent on dr iving conditions. EEA’s fuel economy benefit, AMT versus 6-speed AT in table 3-1 is 2.5%, and falls within VW’s range. More importantly, VW has shown t hat further AMT speed number increase can result in an additional fuel efficiency benefit of up to 10% (7-speed versus 6-speed AMT). While this large benefit is yet to be demonstrated under FTP conditions, EEA feels that AMT separation into discreet 6-speed AMT and 7-speed AMT technologies might be
warranted. The discussion above indicates that 6-speed versus 7-speed automatic transmission fuel economy difference is 0. 8%. EEA expects that similar AMT speed
number increase should deliver at least a similar benefit due to gear ratio spread increase. More precise fuel economy diffe rence should be confirmed when these new transmission models are introduced in the US market.

For CVTs, the EPA FTP fuel economy data s upports the fact that these transmissions can achieve comparable fuel economy per formance versus models equipped with manual transmissions. When CVT is compared to a less efficient 4-speed AT, substantial fuel economy benefits can be realized.Energy and Environmental Analysis, Inc. 2
‐ 13 Table 3-3 compares selected MY 2007 Nis san models equipped with CVT against comparable models with either automatic or manual tran smission. One model, the Nissan Versa, is sold in trim levels with either CVT or 4- speed AT with otherwise identical specifications. De spite the CVT-equipped model being slightly heavier, a fuel economy benefit of 5% is realized compared to 4-speed AT. Other models in Nissan’s lineup do not have comparable AT counterpart s, but CVT comparison against various manuals indicate competitive performance in most cases.

Table 2-3. MY 2007 Vehicle Fuel Economy Comparison, CVT vs. 4-speed AT or Manual All vehicles are FWD; Fuel Ec onomy is EPA Combined Unadjusted.

MODEL Engine Curb Weigh [lbs] Transmission EPA Fuel Economy [mpg] Percent Difference NISSAN VERSA 1.8L I4 2779 CVT 37.7 NISSAN VERSA 1.8L I4 274 9 Auto(L4) 35.9 5.0

NISSAN SENTRA 2L I4 2897 CVT 37.1 NISSAN SENTRA 2L I4 285 3 Manual(M6) 35.8 3.6

NISSAN ALTIMA 2.5L I4 3142 CVT 34.3 NISSAN ALTIMA 2.5L I4 309 3 Manual(M6) 35.0 -1.9

NISSAN ALTIMA 3.5L V6 3334 CVT 28.6 NISSAN ALTIMA 3.5L V6 3268 Manual(M6) 28.2 1.5

Bosch information discussed above indicates that substantial CV T improvements are possible in the future. Theref ore, EEA’s slightly higher f uel economy benefits for CVT in Table 3-1 are defensible, if not conser vative, and should continue to be used.

Concerning the new transmission costs, EEA has received no new information to update the cost data. The 8-Speed AT design add-on RPE (above 4-Speed AT) can be estimated to be about $320 (270$ for 7- Speed plus $50 for an additional gear).Energy and Environmental Analysis 2
‐ 14 

## 2.6 References for Section 3

1 DaimlerChrysler Press Release, “7G-Tr onic: Mercedes Benz Presents the World’s First Seven-speed Automatic Transmissi on for Passenger Cars”, May 14, 2003.

2 J. Greiner, C. Doerr, H. Nauerz, M. Graeve, “The New “7 G-Tronic” of Mercedes-Benz: Innovative Transmission Technology for Better Driving Performance, Comfort and Fuel Economy”, SAE Technica l Paper 2004-01-0649.

3 Automotive Engineering International Maga zine, “Lexus LS460: AEI Best Engineered Vehicle, 2007”, April 2007 Issue.

4 Aisin AW Co., LTD., Informa tional Brochure “Driving Innovat ion”, Distributed at SAE World Congress, 2007.

5 M. Kondo, Y. Hasegawa, et al., “Toyot a AA80E 8-Speed Automatic Transmission with Novel Powertrain Control System”, SAE Technical Paper 2007-01-1311.

6 H. Ota, K. Nozaki, et al ., “Toyota’s World First 8-S peed Automatic Transmission for Passenger Cars”, SAE Te chnical Paper 2007-01-1101.

7 ZF Press Release, “ZF Develops Auto matic 8-Speed Transmission for Passenger Cars”, May 2, 2007.

8 L. Brooke, SAE International Magazine, “Six, Seven, Eight – the Great Gear Debate”,
Article in June 2007 Issue.

9 F. Rudolph, M. Schafer, at al., “The Innovative Seven Sp eed Dual Clutch Gearbox for Volkswagen’s Compact Cars”, Vi enna Motor Symposium, April 2007.

10 Prof. Nick Vaughan, “CVT Opportunity ”, AutoTechnology, February 2007.

11 F. Sluis, T. Dongen, et al., “Efficiency Optimization of the Pushbelt CVT”, SAE Technical Paper 2007-01-1457.Energy and Environmental Analysis, Inc. 3
‐ 1 

# 3 DIESEL AND HYBRID UPDATE

3.1 Light Duty Diesels
New generation, DPF-equi pped light duty diesels (Tier 2 Bin 8) are currently sold in the US by DaimlerChrysler and VW and a major expansion of dies el models is expected in the near future. Audi, BMW, Honda, VW have announced they will offer the Bin 5- compliant light-duty diesel cars by the end of this decade. Other OEMs, such as GM, Ford and Nissan, are planning diesel light duty trucks and SUVs starting in MY 2009. 1
New European data confirms that diesels typi cally offer about 40% improvement in fuel economy compared to gasoline engines on competitive performance basis. 2 Interestingly, the diesel fuel economy advantage increases with t he increased vehicle weight (see Figure 4-1 from Ford ). This is due to the fact that diesels offer very high torque and for larger vehicles such as tr ucks and SUVs, which are designed for towing and off-road capability, gasoline engines must offer very large disp lacement to compete
with diesels.

Figure 3-1. Diesel Comparison versu s Gasoline by Vehicle Weight, . European Data. Diesel vs. Gasoline CO2 Difference is from 20 to 25%.Energy and Environmental Analysis 3
‐ 2 This section examines a few diesel technology development examples and associated fuel economy improvement opportunities. EEA’s updated analysis is also provided.

3.1.1 Diesel Technology Advances Diesel engines are experi encing unprecedented developm ent in Europe as auto manufacturers are adjusting their power tr ain strategies to deal with the EU CO2 regulations and emission standard changes. T hese new technologies are expected in the US market. Two recent examples by BMW and Honda illustrate the magnitude of these new developments.

BMW has announced that one of t heir mainstream diesel engines in Europe, the 2.0L l4 was redesigned and achieved yet another incr ease in fuel efficiency and performance gains. This engine is used in wide variety of products including the 5-Series and X3. 3 The new engine version was completely redesigned with major areas of improvement, compared to the previous generation engine, as follows:

• Friction and mass reduction of parts such as crankshaft bearings, high pressure injection pump;

• Adoption of aluminum crankcase;

• Adoption of 1,800bar piezo CR injection system;

• New high pressure pump with 20% lower power consumption;

• New variable geometry tu rbocharger, EGR and ECU;

• New A/C compressor with clutch

As shown on the engine map in Figure 4-2, the above measures resulted in fuel consumption improvement of up to 10% (against previous generation 2L diesel). While 10% improvement is limited to small area of the map, the 4 to 8% improvement is
realized under most conditions.Energy and Environmental Analysis, Inc. 3
‐ 3 Figure 3-2. Fuel Consumption Improvemen t of BMW’s New 2.0L Diesel Compared to the Previous Generation.

The new engine was specifically designed to work with mild-hybridization, i.e. engine start-stop control and intelligent alternator control. The inte lligent alternator is designed to generate electrical power when the vehicle is in overrun during braking, while the stop-start function shuts down the engine during prolonged idling. With such steps BMW reported that fuel efficiency was further in creased up to 15%. The comparison is for the European 1-Series, which adopted the technology in MY 2007.5 (see Figure 4-3 below). BMW indicated that the new engine will be used on the 3-Series and other appropriate platforms.

The exhaust emissions of the vehicle ar e controlled by closed-coupled DOC/DPF system (SiC catalyzed-type), which is int egrated into one housing. The closed-coupled position maintains catalyst and filter temperatures above 600 ° C under most conditions so regeneration is continuous with mi nimal post-heating requirements.Energy and Environmental Analysis 3
‐ 4 Figure 3-3. Fuel Consumption and Perf ormance of New BM W 1-Series Diesel Compared to Previous Generation Diesel Vehicles.

Honda has announced that the Eu ropean diesel technology will be modified for the US
market and will be able to meet the Tier 2 Bin 5 emissions requirements. 4 The market entry is expected in 2009. Figure 4-4 su mmarizes the new engine and exhaust after treatment configuration. In addition to the latest piezo CR injectors, the engine will use closed-loop cylinder pressure sensors to control combustion. The closed-coupled DOC and DPF, as well as the under-floor NOx trap system, will be used for after treatment.

Figure 3-4. Honda Diesel Technology for the US Market.Energy and Environmental Analysis, Inc. 3
‐ 5 3.1.2 Diesel Exhaust After treatment to Reach Bin 5
The latest announcements indicate that, in near term, light duty diesels in the US are expected to utilize two exhaust system configurat ions in order to reach the Tier 2 Bin5 (CA LEV II LEV) stand ards. The first is DPF and Urea-S CR catalyst combination, the second, is a LNT (Lean NOx Trap) and DPF system. Figure 4-5 illustrates the basic layouts of the two approaches.

Figure 3-5. Basic Configurations for Urea-SCR and LNT-based Diesel After treatment.

AVL has shown that the after treatment selection costs can be modeled as a function of engine size. 5 Since the LNT construction requires precious metals, its costs are expected to scale with the engine displacement (i.e., engine-out gas volume). The SCR system, on the other hand, does not require precious metal support, so costs are dominated by extra hardware for urea dos ing, storage and inject ion. Figure 4-6
illustrates that a tradeoff exists between t hese dominant costs. According to AVL, the break-even is about 1.6L engine size.

The AVL data likely reflects the Euro IV-level diesel engine-out emissions in Europe. As illustrated above, automakers are redesigning their engines to achieve additional engine-out reductions. As a result, the break even point for LNT versus SCR solutions will likely move toward engine size of around 2.4L, as illustrated by Honda announcements (their first engine in the US mark et will be 2.2L or slightly larger).Energy and Environmental Analysis 3
‐ 6 Figure 3-6. Relative Cost Comparison be tween Lean NOx Trap (LNT) and UreaSCR Catalysts. Assumptions: SCR Catalyst and LNT volumes are 1.5 times the engine displacement; precious metal loading for LNT: 100g/ft 3, Costs include sensors and wiring harnesses.
3.1.3 Diesel Summary and Analysis EEA has documented that a light duty di esel provides about 35% fuel economy advantage when compared to gasoline engines. Table 4-1 summarizes this information, including the expected $RPE incr ease, for I4 and V6 engines.

Table 3-1. Light Duty Diesel Fuel Economy Improvement and $RPE Increase. RPE increase is for technologies needed to certify di esels at Tier 2 Bin 5 emissions. 2015+ RPE assumes PCCI/HCCI

. Fuel Economy Benefit [%] Incremental $RPE Notes

I4 Engine 35 + 3 2,200 near term 2,000 (2015+) Compared to gasoline I4, includes after treatment
V6 Engine 35 + 3 3,200 near term 3,000 (2015+) Compared to gasoline V6, w/aftertreatmentEnergy and Environmental Analysis, Inc. 3
‐ 7 Since the new generation diesels equipped with DPFs are available in the US, albeit mostly in the luxury segment, EEA has anal yzed the available models for fuel economy benefit compared to similar conventional gasol ine models. Table 4-2 summarizes this analysis for new diesels introduced in MY 2007 by DaimlerChrysler, on constant displacement basis. Since the same disp lacement gasoline engi nes are not marketed by DaimlerChrysler, other OEM models in the same size cl ass are used. As a result, this comparison method should be used for re ference purposes only since wide range of differences exist among different OEM powertrain configurations.

The constant displacement analysis show s that FTP diesel fuel economy advantage against gasoline is highly variable. One model, the Mercedes E320 Bluetec, has a gasoline competitor, the J aguar S-type, with comparable specifications, including reasonably close curb weight. The Jaguar is tuned for high performance (hence premium gasoline is required) but the dies el still provides 33% advantage (adjusted for transmission difference). Another model, the Mercedes ML320 SUV is comparable to the BMW X5, although the ML320 is equi pped with 7-speed autom atic. The fuel economy increase in this case is about 20%, if the difference is adjusted for transmission advantage. The Jeep Grand Cher okee provides only 10% advantage but the comparison is against the premium X5 so the constant engine displacement comparison is not really useful in this case.Energy and Environmental Analysis 3
‐ 8 Table 3 ‐ 2. MY 2007 LD Diesel Fuel Economy Comparison against Gasoline Models on Equal Displacement Basis.

Fuels Indicated: D-Diesel, P-Prem ium Unleaded, R-Regular Unleaded FE – Fuel Economy, EPA Combined Unadjusted

MODEL Engine TRANS DRIVE FE [MPG] FE Diff. [%] Rated Power [hp] Rated Torque [ft-lbs] Power and Torque Ratio Average CURB WEIGHT [lbs] MERCEDES E320D 3L V6 Auto(L7) R 34.7 208 388 3860 JAGUAR S-TYPE 3.0L 3L V6 Auto(L6) R 25.9 34.0 235 216 1.34 3760
JEEP GRAND CHEROKEE 3L V6 Auto(L5) 4 25.1 215 376 4691 BMW X5 3.0SI 3L I6 Auto(S6) 4 22.8 10.0 260 225 1.24 4982
MERCEDES GL320 CDI 3L V6 Auto(L7) 4 26.1 215 398 5296 BMW X5 3.0SI 3L I6 Auto(S6) 4 22.8 14.5 260 225 1.29 4982
MERCEDES ML320 CDI 3L V6 Auto(L7) 4 27.5 215 398 4817 BMW X5 3.0SI 3L I6 Auto(S6) 4 22.8 20.6 260 225 1.29 4982
MERCEDES R320 CDI 3L V6 Auto(L7) 4 28.2 215 398 5092 BMW X5 3.0SI 3L I6 Auto(S6) 4 22.8 23.7 260 225 1.29 4982

The data in Table 4-2 data indicates t hat diesel engines provide substantial performance advantage, if compared on cons tant displacement basis. Even though diesels do have somewhat lower power ratings , the torque advantage is very large. As a result it was necessary to compare the MY 2007 diesels against gasoline counterparts on performance basis.

The performance method allows the diesel option comparison within the same model family, including reasonably close weight sp ecifications and identical transmissions.
Table 4-3 summarizes the model choices fo r this analysis, including rated power and torque specifications. Note that, when the pow er and torque rating ratios for diesel and gasoline models are averaged, t he results fall reasonably close to unity (from 1.07 to 1.17). While the comparison can not be consi dered to provide a “constant performance” basis, the data is reasonably consistent to draw conclusions.Energy and Environmental Analysis, Inc. 3
‐ 9 The analysis shows that fuel economy advan tage for US diesels, at competitive performance, also varies although the spr ead is relatively narrow from about 26% to 38%. Three models, the Mercedes E320/ R320 and Jeep Grand Cherokee 2WD, do show fuel economy advantage for diesels in t he range of EEA estimates in Table 4-1.
Table 3-3. MY 2007 LD Diesel Fuel Economy Comparison against Gasoline Models on “Competitive Performance” Basis. Fuels Indicated: D-Diesel, P-Prem ium Unleaded, R-Regular Unleaded FE – Fuel Economy, EPA Combined Unadjusted

MODEL Engine TRANS DRIVE FE [MPG] FE Diff. [%] Rated Power [hp] Rated Torque [lb-ft] Power and Torque

Ratio Average CURB WEIGHT [lbs] MERCEDES E320 CDI 3L V6 Auto(L7) R 34.7 208 388 1.14 3860 MERCEDES E350 3.5L V6 Auto(L7) R 25.1 38.3 268 258 3740
GRAND CHEROKEE 3L V6 Auto(L5) R 26.0 215 376 1.07 4460 GRAND CHEROKEE 4.7L V8 Auto(L5) R 19.7 31.9 235 305 4421
GRAND CHEROKEE 3L V6 Auto(L5) 4 25.1 215 376 1.07 4692 GRAND CHEROKEE 4.7L V8 Auto(L5) 4 19.8 26.8 235 305 4691
MERCEDES ML320 CDI 3L V6 Auto(L7) 4 27.5 215 398 1.17 4817 MERCEDES ML350 4MATIC 3.5L V6 Auto(L7) 4 21.8 26.4 268 258 4705
MERCEDES R320 CDI 3L V6 Auto(L7) 4 28.2 215 398 1.17 5092 MERCEDES R350 3.5L V6 Auto(L7) 4 21.3 32.6 268 258 4938 The Jeep Grand Cherokee Limited offers the diesel engine option for a $3,050 price premium. Mercedes diesel models are avail able with diesel engines at a $1,000 price premium. Both Mercedes and J eep offer the same 3L V6 dies el engine, so the current MSRP diesel premium figures should be used fo r reference purpose only, illustrating the current OEM pricing strategies.

Mercedes and Jeep diesel models are equip ped with DPFs and LNT-type aftertreatment but NOx conversion efficiency is not high enough so these vehicles are certified to Bin 8. The add-on technologies will be required to bring these diesels into the Bin 5 compliance. Mercedes announced that the Ur ea-SCR will be used for next generation diesels (Bluetec II). While more resear ch is needed to update the expected costs forEnergy and Environmental Analysis 3
‐ 10 different NOx control solutions, EEA feels that the cost esti mates listed in Table 4-1 are
defensible and should continue to be used fo r the Bin 5-level diesel technology.

The diesel technology development examples in previous sections do provide evidence that next generation diesels in the US will have an opportunity for higher fuel economy
benefit. Therefore the Table 4- 1 fuel economy estimates should also be considered valid, on equal performance basis. 

## 3.2 Hybrid Technology

3.2.1 General Hybrid Product Trends Toyota and Honda have established an early l ead in the hybrid market. Honda hybrid technology represents the 2 nd generation of development, with significant improvements reported for all hybrid components (see Figur e 4-7). Honda has announc ed that the next step in hybrid vehicle development will be the in troduction of an all-new hybrid car to be launched in the US in 2009. 6 This new hybrid vehicle wil l be a dedicated, hybrid-only, model with a target price lower than the cu rrent Civic Hybrid. The projected annual
sales volumes in North Amer ica will be about 100,000 units.

Figure 3-7. Honda Civic HEV 2 nd Generation Technology Improvements.Energy and Environmental Analysis, Inc. 3
‐ 11 Current Toyota HEVs also represent 2 nd generation hybrid technology. Toyota’s key hybrid componentry, such as Power Contro l Unit (PCU), was reported to achieve dramatic power density increase, and likely h ad associated cost reductions with each new model introduction (see Figure 4-8). 7

Toyota has announced that the THS (Toyota Hybrid System) architecture would be expanded to virtually every mainstream nameplate with worldwide sales volumes projected to approach 1 million units/year by early next decade. The company has hinted that the cost premium for hybrids would be “halved” compared to current hybrids.



### 0 1 2 3 4 5 6

MY 2004 MY 2005 MY 2006 MY 2007Relative Power Density

Figure 3-8. Toyota Hybrid Power Control Unit Relative Power Density Increase, MYs 2004-2007.
MY 2004 is PCU performance for the Prius II, MY 2007 – Lexus LS600h

GM is responding with a aggressive HEV stra tegy and will market at least 12 models in high volume car and truck lines by 2010 (s ee Figure 4-9). GM’s first BAS (Belt Alternator Starter) mild hybrid system, used on the Saturn Vue, was designed to improve fuel economy by up to 20% without sacrificing performance. The TMH (Two Mode Hybrid) system is expected to deliver a minimum 25% improvement in trucks andEnergy and Environmental Analysis 3
‐ 12 SUVs. The TMH application on the Saturn V ue will deliver up to 45% fuel economy improvement over t he current base Vue.

GM has announced that the Sa turn Vue TMH will also be capable of being driven in limited electric-only mode (i.e., PHEV- Plug-in Hybrid configur ation), assuming that the Lithium-Ion battery packs materialize, as anticipated. 8 Even more advanced PHEV architecture is planned, once again subject to LiI technology development, in the form of Chevy Volt concept with a target all-electric range of 40 miles.

Figure 3-9. GM Hybrid Product Plan.
Source: GM 9

Ford announced that MY2008 Escape was re freshed with new exterior panels and refined interior. The new Escape Hybrid ca rries an EPA rating (u sing the new reporting system) of 34 mpg city, 30 mpg highway, 32 mpg combined. The 2007 Escape Hybrid has a rating (adjusted using the new syst em) of 31 mpg city, 29 mpg highway, and 30Energy and Environmental Analysis, Inc. 3
‐ 13 mpg combined. Based on these figures, fuel economy performance increased 10%, 3%, and 7% for city, highway and combined, respectively.

Ford reported that these lar ge fuel economy gains were possible through revisions to the ECU software and hybrid electronics, wh ich improved transition between gasoline and electric operation. Also, the regenerative brakes were reworked for better feel and efficiency. A new Electric Power Assist Steering (EPAS) was also implemented.

3.2.2 Supplier Announcements Valeo is known for its mild hybridizat ion technology developed in Europe called StARS. 10 The system is relatively simple and its main component is a belt-driven starter/generator controlled by separate power electronics. The StARS is able to provide start-stop function, regenerat ive braking and some torque assistance. The system operates at conventional 12V voltage, al though regenerative br aking-capable system requires additional power st orage through EDLC. DC/DC converter is used to provide floating system voltage up to 24V. The torque assist system is capable to provide up to 4kW additional power.

Valeo has shown that, depending on the system’s functionality, mild-hybridization can provide up to 20% fuel economy benefit (see Figure 4-10). The company claims that under real city congested driving conditions (based on testing in Paris, France), the start-stop function alone can provide up to 25% fuel economy benefit (officially NEDC benefit is 6%).Energy and Environmental Analysis 3
‐ 14 Figure 3-10. Valeo StARS Strategy and Fuel Economy Benefits.

Siemens VDO published results of the fuel efficiency improvement potential analysis for various hybrid technologies. 11 Their data is summarized in Table 4-4 and converted to fuel economy improvement potent ial. Base vehicle conditions were not clearly defined by Siemens but their data illust rates that very large fuel economy gains, 33 to 77%, are possible with fully optimized hybrids depend ing on the test cycle conditions. Mild hybridization can yield more t han 18% fuel economy improvement.
Table 3-4. Fuel Economy Improvement Pote ntial of Various Hybrid Technologies.
Source: Siemens VDO

Add On Technology Consumption [l/100km] Cumulative Consumption Improvement [%] Fuel Economy Improvement [%] Base 9.17 Optimized IC Engine and 6-speed Transmission 8.33 9.2 10.1 Integrated Starter Generator (ISG) 8.06 12.1 13.8 Start-Stop Operation 7.57 17.4 21.2 Regenerative Braking with Adoptive Shifting Strategy 6.49 29.2 41.2 Electric Launch 5.92 35.4 54.8 Electric Drive 5.29 42.3 73.3 Optimized Accessories 5.18 43.5 77.0Energy and Environmental Analysis, Inc. 3
‐ 15 3.2.3 Summary and Analysis EEA previous estimates for fuel econom y and RPE increase for various hybrid packages are summarized in Table 4-5 below.

Table 3-5. Hybridization RPE Increase and Fuel Economy Benefits RPE at high sales volume, effects of learning and technology simulated.
Technology 2005 2010 2015
BAS Hybrid Component RPE [$] 950 800 660 BAS FE Benefit [%] 8 8 9 IMA Hybrid Component RPE [$] 2,950 2,525 2,100 IMA System FE Benefit [%] 51. 53 56 2 motor Hybrid Component RPE [$] 4,500 3,900 3,300 2- motor Hybrid System FE Benefit [%] 60 65 70
Since the technology has reached mass produc tion volumes, the EPA FTP testing data can be used to confirm the fuel economy advant age trends for hybrids. The first set of data, presented in Table 4-6, specifies the MY 2007 hybrid vehicles and compares their fuel economy and other parameters against vehicl es in the same size class on an equal displacement basis . Note that Toyota Prius and H onda Civic HEVs are equipped with unique downsized engines, which are not available in the US conventional vehicles.

When the Prius and Civic, a well as the Lexus 450h (which is more than 600lbs heavier than comparable vehicles with the same engine size), are excluded from the analysis, fuel economy difference is relatively consistent among many hybrid models and averages about 12% for mild hy brids (Aura and Vue) and 40% for full 2-motor hybrids. The Honda HEVs are only m odels with the IMA-type single motor system. The Accord HEV provides a 32.5% fuel economy advant age compared to the conventional 3L V6
Accord.Energy and Environmental Analysis 3
‐ 16 Table 3-6. MY 2007 Hybrid Vehicle Fue l Economy, Key Specification and MSRP Comparison on Constant Displacement Basis

. FE – Fuel Economy – EPA Combined Unadjusted; *-Honda Civic and Toyota Prius HEVs do not have “Equal Engine Displacement” Counterparts. **-Conventional Saturn Vue does not have the 2.4L option (2.2L I4 is the standard engine).

MFR CAR LINE DISP CYL TRANS DRIVE Fuel Economy [mpg] FE Diff. [%] Curb Weight [lbs] Mild (BAS) Hybrid Comparison SATURN AURA HYBRID 2.4 4 Auto(L4) F 35.7 3529 CHRYSLER SEBRING 2.4 4 Au to(L4) F 32.0 11.6 3287 TOYOTA CAMRY 2.4 4 Auto(L5) F 31.9 11.8 3307
SATURN VUE HYBRID 2.4 4 Auto(L4) F 34.0 3474 CHEVROLET HHR PANEL FWD 2.4 4 Auto(L4) F 30.5 11.4 3208 SATURN VUE** 2.2 4 Auto(L4) F 29.8 14.1 3207
Honda IMA-Type Hybrid Comparison HONDA CIVIC HYBRID* 1.3 4 Auto(AV) F 58.8 2875 HYUNDAI ACCENT 1.6 4 Au to(L4) F 36.7 60.2 2403
HONDA ACCORD HYBRID 3 6 Auto(L5) F 36.3 3605 HONDA ACCORD 3 6 Auto (L5) F 27.4 32.5 3344
2-Motor Hybrid Comparison NISSAN ALTIMA HYBRID 2.5 4 Auto(AV) F 46.7 3482 NISSAN ALTIMA 2.5 4 Auto(AV) F 34.3 36.1 3184
TOYOTA CAMRY HYBRID 2.4 4 Auto(AV) F 45.9 3680 TOYOTA CAMRY 2.4 4 Auto(L5) F 31.9 43.8 3307
TOYOTA PRIUS* 1.5 4 Auto(AV) F 65.8 2932 NISSAN VERSA 1.8 4 Auto(AV) F 37.7 74.6 2749
FORD ESCAPE HYBRID FWD 2.3 4 Auto(AV) F 40.6 3627 FORD ESCAPE FWD 2.3 4 Auto (L4) F 28.1 44.7 3256
LEXUS RX 400H 2WD 3.3 6 Auto(AV) F 35.0 4190 HYUNDAI SANTAFE 2WD 3.3 6 Auto(L5) F 25.5 37.1 4022
TOYOTA HIGHLANDER HYBRID 2WD 3.3 6 Auto(AV) F 35.0 4070 TOYOTA HIGHLANDER 2WD 3.3 6 Auto(L5) F 25.0 39.9 3649

FORD ESCAPE HYBRID 4WD 2.3 4 Auto(AV) 4 36.5 3792 FORD ESCAPE 4WD 2.3 4 Auto (L4) 4 26.1 39.4 3407
LEXUS RX 400H 4WD 3.3 6 Auto(AV) 4 34.3 4365 HYUNDAI SANTAFE 4WD 3.3 6 Auto(L5) 4 24.8 38.0 4322

MERCURY MARINER HYBRID 4WD 2. 3 4 Auto(AV) 4 36.5 3787 MERCURY MARINER 4WD 2.3 4 Auto(L4) 4 26.1 39.4 3409

TOYOTA HIGHLANDER HYBRID 4WD 3.3 6 Auto(AV) 4 34.3 4275 TOYOTA HIGHLANDER 4WD 3.3 6 Auto(L5) 4 24.1 42.4 3880Energy and Environmental Analysis, Inc. 3
‐ 17 The MSRP comparison at constant displacem ent is meaningful only in cases where the same engines are used in hybrids vs. non hybr id models within the same model family. The MSRP price figures advertised by OEMs are substantially higher for hybrid models and vary from $2,525 (Escape 2WD) to $7,740 (A ccord). It should be noted that in most cases the hybrid models are sold with ot her upgrades, so the MSRP comparison does not directly relate to hybrid costs, although EEA’s estimates do fall with this range.

In addition to large fuel economy advantage, t he full hybrid vehicles do offer large performance gain due to the electrical traction motor power assist availability. That is the reason why Toyota Prius and Honda Civi c HEVs are able to achieve desirable performance despite highly downsized, about 30%, IC engines.

Table 4-7 summarizes the MY 2007 hybrid vehicle data compared with corresponding conventional models, in most cases, equi pped with larger engines . The total power rating was used as a proxy for the conventi onal model selection on “competitive power” basis. The mild hybrids are e xcluded from this analysis since their power assist feature provides only marginal performance advantage.

The analysis shows that very large fuel ec onomy gains are realized in most hybrid cases on a “competitive performance basis”, al though the results are highly variable. If the hybrids are compared to leading fuel economy performance vehicles, such as Murano 3.5L CVT, the advantage is about 35%. Fully optimized HEV offerings, such as the Prius, can achieve as much as 75% fuel economy advantage, on a competitive performance basis.Energy and Environmental Analysis 3
‐ 18 Table 3-7. MY 2007 Hybrid Vehicle Fuel Economy, Key Specifications and MSRP Comparison on “Competitive Performance Basis”. FE – Fuel Economy – is EPA Combined Unadjusted; *-With MY 2007, Toyota upgraded the Camry V6 to 3.5L. The previous, MY2006 3.3L V6, model provides better power rating match. **-Ford markets the Escape and Mariner HEVs with de-rated power IC engine but claims the “V6-like” acceleration performance. ***The Altima V6 is rated 270hp so Saturn Aura is used to provide better performance match.

MFR CAR LINE DISP CYL TRANS DRIVE Fuel Economy [mpg] FE Diff. [%] FUEL Total Power [hp] Curb Weight [lbs] Honda IMA-Type Hybrid Comparison HONDA CIVIC HYBRID 1.3 4 Au to(AV) F 58.8 R 110 2875 HONDA CIVIC 1.8 4 Auto( L5) F 39.0 50.9 R 140 2690
HONDA ACCORD HYBRID 3 6 Auto(L5) F 36.3 R 253 3605 HONDA ACCORD 3 6 Auto( L5) F 27.4 32.5 R 244 3344
2-Motor Hybrid Comparison NISSAN ALTIMA HYBRID 2.5 4 Auto(AV) F 46.7 R 198 3482 SATURN AURA*** 3.5 6 Auto(L4) F 28.5 64.1 R 224 3578
TOYOTA CAMRY HYBRID 2.4 4 Auto(AV) F 45.9 R 192 3680 TOYOTA CAMRY (MY 2006)* 3.3 6 Auto(S5) F 27.8 65.3 R 190 3340
TOYOTA PRIUS 1.5 4 Auto(AV) F 65.8 R 110 2932 NISSAN VERSA 1.8 4 Auto(AV) F 37.7 74.6 R 122 2749
FORD ESCAPE HYBRID FWD** 2.3 4 Auto(AV) F 40.6 R 155 3627 FORD ESCAPE FWD 3 6 Auto(L4) F 25.4 59.7 R 200 3300
LEXUS RX 400H 2WD 3.3 6 Auto(AV) F 35.0 P 268 4190 LEXUS RX 350 2WD 3.5 6 Auto(L5) F 25.7 36.0 P 270 3870
TOYOTA HIGHLANDER HYBRID 2WD 3.3 6 Auto(AV) F 35.0 R 268 4070 NISSAN MURANO 3.5 6 Auto (AV) F 25.9 35.3 P 240 3983
FORD ESCAPE HYBRID 4WD** 2.3 4 Auto(AV) 4 36.5 R 155 3792 FORD ESCAPE 4WD 3 6 Auto(L4) 4 24.1 51.5 R 200 3492
LEXUS RX 400H 4WD 3.3 6 Auto(AV) 4 34.3 P 268 4365 LEXUS RX 350 4WD 3.5 6 Auto(S5) 4 24.6 39.3 P 270 4090
MERCURY MARINER HYBRID 4WD** 2.3 4 Auto(AV) 4 36.5 R 155 3787 MERCURY MARINER 4WD 3 6 Auto (L4) 4 24.1 51.5 R 200 3464
TOYOTA HIGHLANDER HYBRID 4WD 3.3 6 Auto(AV) 4 34.3 R 268 4275 NISSAN MURANO AWD 3.5 6 Au to(AV) 4 25.2 36.0 P 240 3983

The MSRP figures, on performance basis, c an be used to gage the current pricing strategies for hybrids and do appear to provide useful reference points. In some cases, for example the Altima HEV ve rsus Altima V6, the MSRP di fference is relatively lowEnergy and Environmental Analysis, Inc. 3
‐ 19 ($990). In other cases, such Escape HEV versus Escape V6 ($3,805) the difference approaches EEA estimates.

The EEA fuel economy estimates in Table 4- 5 for the full 2-motor and IMA-type hybrids do agree with the FTP near term dat a on a competitive performance basis for models that are optimized for fuel economy perform ance (such as Prius, Civic, Altima and Escape/Mariner). However, the mild hybr ids in 2007 do appear to report much higher fuel economy advantage relative to the EEA figures largely because they incorporate other technological improvem ents. The Vue fuel economy performance is tricky to compare because the regular I4 model uses a smaller 2.2L engine, while the hybrid Vue
is over 200lbs heavier. If these differenc es are accounted for, the fuel economy difference would increase significantly. Sim ilarly, the Aura BAS comparison to regular Aura is not meaningful since the regular mo del is only available with V6 engines in 2007. If the Aura BAS is com pared to 3.5L Aura, the fuel economy difference is 25%.

Technology development examples and new model announcements described in previous sections illustrate that hybrids wil l likely achieve even larger fuel economy improvements compared to systems represen ted by MY 2007 data. Also large cost reductions can be anticipated with next generat ion HEVs as new optimized systems and suppliers enter the mark et with mass volumes.Energy and Environmental Analysis 3
‐ 20 

## 3.3 References for Section 4

1 L. Wehrly, EPA, “Light-Duty Diesels in the US”, Presentation to the 2007 SAE Government Industry M eeting, May 16, 2007.

2 G. Schmidt, Ford “Light Duty Diesels in North Amer ica, a Huge Opportunity”,
Presentation at DEER Conference, 2006.

3 F. Steinparzer, W. Mattes, et al., “The New BMW 2.0L 4-Cylinder Die sel Engine”, Vienna Motor Symposium, April 2007.

4 T. Abe, “Clean Technology for Global Di esel Expansion”, Presentation to the 2007 SAE Government Industry Meeting, May 16, 2007.

5 T. Cartus, M. Schussler , et al., “SCR and DPF – from the Concept to Series Production. Mastering Complex, Mult i-Dimensional Challenges”, Vienna Motor Symposium, April 2007.

6 J. German, “Honda Statement before t he Senate Committee on Energy and Natural Resources”, US Senat e, January 30, 2007.

7 Y. Sakai, H. Ishiyama, “P ower Control Unit for High Power Hybrid System”, SAE Technical Paper 2007-01-0271.

8 G. Smyth, A. Lippert, “The Drive for Energy Diversity a nd Sustainability: the Impact on Transportation Fuels and Propulsion System Portfolios”, Vienna Mo tor Symposium, April 2007.

9 P. Savagian, “The GM 2Mode Hybrid S ystem and 2008 Hybrid Chevrolet Tahoe and GMC Yukon”, Presentation to the 2007 SAE Government I ndustry Meeting, May 16,
2007.

10 Y. Dubel, “Valeo StARS Roadmap”, Present ation Provided to EEA, June 19, 2007.

11 Dr. Klaus Egger, “Elect ronics and Mechantronics Increase Fuel Economy”, Aachen Colloquium, Automobile and Engine Technology, October 2006.