## Evaluation of the Proposed SmartW ay Fuel Efficiency Test Protocol for Medium- and Heavy-duty Vehicles
Report A: Conven tional and Hybrid Utility Trucks

ERMS Report N o 

### 08-38

Prepared by

Martha Christenson Emissions Research and Measurement Section Environment Canada

Justin Greuel Office of Transportation & Air Quality U.S. Environmental Protection Agency

### NOTICE

________________________ _____________________ ___________________ This report has not undergone detailed technical review by the Science and Technology Branch. The content does not necessarily reflect the views and policies of Environment Canada. Mention of trade names or commercial products does not constitute endorsement for use. This unedited version is undergoing a limited distribution to transfer the information to people working in related studies. This distribution is not intended to signify publication and if the report is referenced, the author should cite it as an unpublished report of the Directorate indicated below.

Any comments concerning its content should be directed to:

Environment Canada Air Quality Research Science and Technology Branch 335 River Road Ottawa, Ontario, Canada K1A 0H3

2

# ACKNOWLEDGEMENTS
The authors gratefully acknowledge the st aff of the Emissions Research and Measurement Section of Environment Canada for undertaking the work described in this report, the U.S. Environmental Pr otection Agency’s Office of Transportation & Air Quality for recrui ting the test vehicles and providing feedback and support throughout testing and reporting, Florida Power & Light for donating the two test vehicles, and Eaton Corporation for providing technical support.

Funding for this project was provided by Environment Canada, and the Natural Resources Canada Program of Energy Re search and Development: specifically the Electric Mobility Program.

3

### 1.0 INTRODUCTION ................................................................................................................... 5

2.0 VEHICLE INFORMATION .................................................................................................. 6

3.0 FUEL PROPERTIES .............................................................................................................. 7

4.0 PROCEDURE .......................................................................................................................... 7

4.1 D RIVING 

### C YCLES 

### ...................................................................................................................... 7 4.2 D UTY 

### L OAD 

### C YCLES 

### .............................................................................................................. 10 4.3 D YNAMOMETER 

### S ET



### - UP 

### ......................................................................................................... 11

5.0 DATA ACQUISITION AND ANALYSIS ........................................................................... 15

6.0 RESULTS

............................................................................................................................... 17

6.1 T ARGET VS



### . A CTUAL 

### D RIVE 

### C YCLE AND 

### D UTY 

### C YCLE 

### ...................................................... 17 6.2 D RIVE 

### C YCLE 

### R ESULTS 

### ......................................................................................................... 19 6.3 D UTY CYCLE AND IDLE RESULTS 

### ........................................................................................... 24 6.4 S AMPLE 

### S IZE 

### C ALCULATION AND 

### S TATISTICS 

### .................................................................... 30 6.5 F UEL 

### E FFICIENCY 

### I MPROVEMENTS AND 

### E MISSION 

### R EDUCTIONS 

### ..................................... 31 6.6 C OLD 

### T EMPERATURE 

### I MPACTS 

### ............................................................................................ 35

7.0 CONCLUSIONS AND RECOMMENDATIONS .............................................................. 36

REFERENCES ............................................................................................................................ 38

APPENDIX A – VEHICLE SPECIFICATIONS ..................................................................... 40



### 4

# 1.0 INTRODUCTION The new SmartWay Fuel Effi ciency Test Protocol [1] was developed by the U.S. EPA with the goal of provid ing a standardized, objective, consistent test procedure to measure the f uel consumption of medium and heavy duty vehicles used in on-road applications. The protocol is intended to be used on a voluntary basis to determine if vehicles meet Sm artWay performance specifications. The procedure covers heavy duty vehicles as defined by 40 CFR § 86.082-2 and § 86.090-2. These vehicles ar e rated at over 8,500 lbs GVWR, or have a curb weight of more than 6,000 lbs, or have a bas ic vehicle frontal area of over of 45 square feet.

In addition to determining if vehicles m eet SmartWay perform ance specifications, the new protocol provides a method for benchmarking new technologies and comparing vehicle designs within a giv en application. Existing certification requirements for heavy duty vehicle manufac turers are based on the U.S. EPA emission standards for engines (40 CFR Part 86, Subpart N) and do not take into account benefits from hybrid drive-trains or other efficient designs (improved aerodynamics, low rolling resistance tires etc.).

The Emissions Research and Measurement Section (E RMS) of Environment Canada, in collaboration with the U.S. E PA, is providing input to the evaluation and refinement of the new SmartWay test protocol. The ERMS is performing the chassis dynamometer portion of the SmartWay Test Protocol at its test facility in Ottawa, ON, and providing feedback to the U.S. EPA on the draf t protocol. Prior to these dynamometer tests, track tests (including r oad load measurements using coastdown techniques) were completed at the Aber deen Test Center (ATC) in Aberdeen, Maryland. Vehicles cove red by the draft prot ocol include both conventional and hybrid versions of utilit y trucks, transit buses, refuse haulers, class 8 line haul trucks, and parcel deliver y trucks. Goals of this test program include:

• 

### Refinement of the Smar tWay Test Protocol

• 

### Quantification of benefits prov ided by hybrid vehicles

• 

### Establishment of a relative equi valence between track and chassis

dynamometer testing

• 

### Quantification of test to test variability

• 

### Evaluation of the propos ed statistical methods

• 

### Determination of the impacts of PTO and auxiliary loads

• 

### Assessment of the adequacy of toleranc es for target vs. actual trace

speeds during chassis dynamometer testing

• 

### Characterization of typical CO 2 

### emission rates

The following report conveys results of t he first round of testing conducted at the ERMS, and provides recommendations for fu ture testing and refinements of the SmartWay Test Protocol. The draft prot ocol was used to conduct emissions and fuel consumption testing on two utility boom trucks in August and September,

5

### 2008. The conventional vehicle was an Inte rnational 4300 chassi s with a Navistar DT466 engine, an Allison 5-sp eed automatic transmissi on, and an Altec L42A (42 ft) aerial boom. The hybrid vehicle had a similar chassis, engine, and boom, but incorporated an Eaton parallel hybrid el ectric system in place of the standard transmission.

The SmartWay Test Protocol proposes us e of the Composite International Truck Local Cycle and Commuter (CILCC) trans ient cycle for chassis dynamometer and track testing of utility boom trucks. The protocol acknowledges the need to account for power take-off (PTO) operati onal loads, but proposes no specific duty cycles for testing. For purposes of this test program, a 10-minute idle test was employed and EPA staff recommended two additional duty cycles developed for a similar study [3] at the Southwest Resear ch Institute (SwRI). Additional testing was performed to evaluate system sensit ivities on other standard drive cycles and cold climate performance. This included testing on the LA4 drive cycle at standard temperature (22 o 

### C), and on the heavy duty UDDS drive cycle at both 22 o 

### C and -7 o 

### C. Lastly, testing was conducted on a standard drive cycle with 10% road load reduction to evaluate the effect s of potential variability in coastdown techniques.



# 2.0 VEHICLE INFORMATION

The vehicles tested were c onventional and hybrid utility boom trucks, pictured in Figure 1 . The trucks had similar chassis a nd hydraulic system s, but one had a conventional drive train, while th e other used Eat on Corporation’s 1 

### parallel hybrid electric drive train. Both vehicles were equipped with EGR and oxidation catalysts. Vehicle specificati ons are given in Appendix A.

Figure 1: Conventional and hybrid utility trucks

1 Further specifications on the hybrid system can be found in Eaton Publication EH-8E306A-CD at http://www.eaton.com/ecm/idcplg ?IdcService=GET_FILE&dID=250730. All specifications are identical to the system tested with the exception of the high-voltage battery system. The system tested utilized nickel-metal hydride batte ries instead of lithium ion batteries.



### 6

# 3.0 FUEL PROPERTIES The fuel used was ULSD Type 2-D distil late (reference 40 CFR §86.1313-2007), and had the properties listed in Table 1 . Fuel analysis was performed by the Alberta Research Council.

Table 1: Fuel Properties



### U.S. EPA ULSD #2D
Density (kg/m 3 @15°C) 845.9 Specific Gravity (kg/L, 60/60°F) 0.8463 Gravity deg API=141.5/SG-131.5 35.7 Cetane Number (ASTM D613) 44.9 Carbon (wt%) 86.24 Hydrogen (wt%) 13.41 Nitrogen (ppm) 3.66 Total Sulfur % (max) 0.000011 Total Sulfur (ppm) 11
Volume % Aromatics 28.3
% Olefins 3.4
% Saturates 68.3
Flashpoint, min 0 C 68
Cloud Point max °C -22 Kinematic Viscosity, Centistokes 2.455 Net Heating Value (btu/lb) 18313 Net Heating Value MJ/kg 42.6 IBP (initial boiling point) 125.3
10% 188.4
50% 261.2
90% 329
End Point 389



# 4.0 PROCEDURE
Three driving cycles, two duty load cycles, and a 10-minute idle test were employed to investigate fuel consumption and emission ra tes of the utility trucks. Cold temperature impacts were examin ed on select cycles for both hybrid and conventional trucks.

4.1 Driving Cycles Characteristics of each driving cycle are given in Table 2 and the cycles are described in the following sections.

7Table 2: Driving Cycle Characteristics Ave Speed (mph) Stdev. Speed Max Speed (mph) Max Accel. (mph/s) Max Decel (mph/s) Total time (s) Idle time (s) Total Dist. (mi) No. of Idle Periods

LA4 19.6 14.7 56.7 3.3 -3.3 1370 260 7.45 18 HD UDDS 18.84 19.84 58 4. 19 -4.51 2121 706 11.1 27

CILCC 13.89 12.4 55 2.5 -2.5 3192 562 12.32 25



### Combined International Local and Commuter Cycle (CILCC):

The CILCC was developed by the U.S. Department of Energy’s National Renewable Energy Laborator y, Eaton Corporation, and International Truck and Engine Corporation. The CILCC speed vs. time sequence is given in Figure 2

. This cycle is currently recommended in the SmartWay Test Protocol draft document for utility service truck testing. The cycle has an average speed of 13.9 mph, a maximum speed of 55 mph, and covers a dist ance of 12.3 mi with 25 stops.

CILCC Driving Cycle

0 10 20 30 40 50 60

0 500 1000 1500 2000 2500 3000 Time (sec)Speed, mph

Figure 2: CILCC Speed vs. Time Schedule



### LA4 Cycle:

The LA4 drive cycle (also known as the Urban Dynamometer Driving Schedule or UDDS) was developed by the U.S. EPA to simulate lo w speed urban driving with mild accelerations, and is currently used as part of the Feder al Test Procedure for determining light-duty vehicle emissi ons compliance in North America. The cycle has an average speed of 19.6 m ph and a maximum speed of 56.7 mph. The speed vs. time schedule is shown in Figure 3

.

8

### LA4 Driving Cycle

0 10 20 30 40 50 60

0 200 400 600 800 1000 1200 1400 Time (sec)Speed, mph

Figure 3: LA4 Speed vs. Time Schedule



### Heavy-Duty UDDS

The heavy-duty urban dynamometer drivi ng cycle (HD UDDS) wa s developed by the U.S. EPA for heavy duty vehicle chas sis dynamometer testing, and is the basis for the FTP transient engine dynam ometer cycle. It has an average speed of 18.9 mph and maximum speed of 58 mph. The HD UDDS speed vs. time trace is shown in Figure 4

.

9

### HD UDDS

0 10 20 30 40 50 60

0 200 400 600 800 1000 1200 Time (sec)Speed, mph

Figure 4: HD UDDS Speed vs. Time



### 4.2 Duty Load Cycles Two hydraulic load cycles were recommended by U.S. EPA staff to evaluate emissions and fuel consumpt ion during operation of the hydraulic lift arm. The pressure vs. time schedules are shown in Figure 5 and Figure 6 and have been sourced from a SwRI study [3].

Attempts were made to attain the required pressures by raising the lift arm using the boom operator hand controls and rotati ng it for the specified times. To achieve the lower pressure at the end of Duty Cycle B, low-idle mode was used on the conventional truck. This was not available for the hybrid truck, and therefore the lowered pressure at the end of Duty Cycle B was not possible. In the previous study at SwRI, an auxiliar y circuit was connected to the truck’s hydraulic tool connection port to artifica lly load the system, and this allowed for consistent and accurate loading. Such a ci rcuit is specialized and is not currently available at most emission test facilities.

10

### Duty Load A

0 500 1000 1500 2000 2500

0 500 1000 1500 2000 Time (sec)Pressure (PSI)

Figure 5: Duty Cycle A



### Duty Load B

0 500 1000 1500 2000 2500

0 500 1000 1500 2000 Time (sec)Pressure (PSI)

Figure 6: Duty Cycle B



### 4.3 Dynamometer Set-up
Vehicles were tested on a single roll chassis dynam ometer system with a 0.61m (24 inch) diameter roll. Before testing, it was necessary to override the hybrid vehicle’s anti-lock brake system (ABS) f ault codes for driving on the two-wheel (single roll) dynamometer. Otherwise, the vehicle’s ABS would interpret nonrotation of the front set of wheels as a malfunctioning system. This would inadvertently affect normal operation of the remaining vehicle systems, including

11

### engine transmission and the regenerative braking system. It was also necessary to disable augmented braking on the dynamometer in order to accurately simulate inertia and road load during brak ing and allow for pr oper functioning of the regenerative braking system. The i nertia weight and road loads were simulated during testing us ing a 400 Hp direct current motor. The chassis dynamometer inertia weight s were set at 20,242 lbs for the conventional truck and 23,062 lbs for the hybrid truck. The truck weights we re provided by the U.S. EPA based on the actual weights tak en at each wheel. A fi xed speed fan was used to provide engine cooling air.

On-road coast downs had previously bee n performed in accordance with SAE J2263 on a 3 mile test tra ck at the Aberdeen Test Ce nter (ATC) in Aberdeen, Maryland. Although the procedure recommends coasting down from 71.5 mph to 9.3 mph, the maximum speed was only 65 mph because t he test vehicles were speed governed at this speed. It should be noted that J2263 is tr aditionally used for determining road load of light-duty vehicles and it s use may be questionable for heavy-duty applications. Prior to conduc ting coast down runs for the hybrid truck, EPA confirmed with Eaton that regenerat ive braking would not be active while the transmission was in neutral.

The ERMS was provided with data for five coast downs in each direction for each vehicle. Dynamometer target coefficient s were derived from the resulting speedtime data, and dynamometer set coeffici ents were obtained by performing coast downs on the chassis dynam ometer according to SAE J2264. Target and set coefficients, as defined in SAE J2264 § 3.12 with units changed to HP @ 50 mph, are provided in Table 3

.
Table 3: Road load coefficients (HP @ 50mph) 

### Coefficients A B C Target 22.2 0 39 Conventional Set 5.742 -5.493 37.566 Target 26.9 0 39 Hybrid Set 8.776 -4.949 37.948

Speed vs. time for each of the on-road coast downs is shown in Figure 7 , along with the corresponding dynamometer speed–time data generated after dynamometer calibration according to SAE J2264. On-road, the speeds were relatively consistent from run to run between 65 and 30 mph. Between 30 and 15 mph, the conventional vehicle slowed more quickly than the hybrid vehicle. In fact, the deceleration rate of the hybrid vehicle decre ased substantially between 30 and 20 mph. Below approximately 15 mph, however, the hybrid’s speed dropped quickly and the hybrid came to re st, on average, more rapidly than the conventional vehicle. This contradicts the SwRI study [3], where the hybrid took longer to coast down than did the conventional vehicle.

120 10 20 30 40 50 60 70 80

-10 40 90 140 190 240 290 340 390 440 490 Time [s]Speed [mph] Hy Run 1 Hy Run 2 Hy Run 3 Hy Run 4 Hy Run 5 Hy Run 6 Hy Run 7 Hy Run 8 Hy Run 9 Hy Run 10 Conv. Run 1
Conv. Run 2
Conv. Run 3
Conv. Run 4
Conv. Run 5
Conv. Run 6
Conv. Run 7
Conv. Run 8
Conv. Run 9
Conv. Run 10 Hybrid Dyno Speed Conv. Dyno Speed

Figure 7: Speed vs. time for coast-downs on-road, and on the chassis dynamometer



### Road load ( Figure 8 ) was higher for the hybrid compared to the conventional vehicle. At 60 mph, the road load experi enced by the hybrid was 5.5 HP higher than for the conventional truck. The di fference between tar get road load power and the dynamometer power setting provides an indication of the parasitic power losses in the vehicle drive train.

130 20 40 60 80 100 120

0 1 0 2 0 3 0 4 0 5 0 6 0 7 Speed [mph]HP

0 Hybrid Target RL Hybrid Dyno Settings Conv. Target RL Conv. Dyno Settings

Figure 8: Road load targets and dynamometer settings



### Figure 9 shows road load versus speed cu rves for the hybrid utility truck. The “Road Load Used” curve repr esents the road load expe rienced by the truck during testing. This curve is based on an average of all 10 on-road coast downs. To illustrate the variability in the on-road coast down data, the minimum and maximum road-load curves calculated fr om individual on-road coast downs are shown.

The “10% Reduced Road Load” curve, shown in light blue, is a curve calculated based on a 10% reduction in each road load coefficient of the “Road Load Used” curve. This should represent, approximatel y, the road load experienced by the utility truck during the “10% Reduced Ro ad Load” tests performed on the hybrid utility truck. It should be noted that the 10% reduction was only applied to the set coefficients, so the curve shown in Figure 9 may slightly over-estimate the reduction in road-load experienced by the truck during testing.

140 20 40 60 80 100 120

0 1 0 2 0 3 0 4 0 5 0 6 0 7 Speed [mph]HP

0 Road Load Used
Minimum Road Load
Maximum Road Load
10% Reduced Road Load

Figure 9: Road load variability for hybrid utility truck



# 5.0 DATA ACQUISITION AND ANALYSIS

An SAE J1939 compliant Ne xiq USB-Link and Eaton Se rvice Ranger software were provided by Eaton for recording hybr id battery state of charge (SOC) data.

In order to measure hydraulic pressure, a pressure transducer (model PX35D0- 3KGV with serial number 39246) was connec ted to the truck’s hydraulic tool connection port located near the boom operator hand controls (see Figure 10). Prior to use the transducer was calib rated by Omegadyne Inc. between 0 and 3000 PSI.

15Figure 10: Hydraulic tool port



### The total exhaust stream produced by eac h truck was collected and diluted using a constant volume sampling (CVS) dilu tion system with a total dilute exhaust volume of 2000 scfm. The dilution air was taken from the test cell and was conditioned by HEPA filtrati on for removal of particulate matter. The total volume of raw exhaust was transfe rred from each truck to the CVS through a 6 inch diameter flexible, stainless steel pipe t hat was insulated. The raw exhaust was then diluted with laboratory air and the mi xture directed through a critical flow venturi. During the exhaust emissions te st continuously proportioned samples of the dilute exhaust mixture and the dilu tion air were collected and stored in sample bags for analysis.

Table 4 summarizes the exhaust sample coll ection and analysis method for each compound.

Table 4: Exhaust Sample Collection and Analysis 

### Compound Analysis Method Sample Collection

Carbon Dioxide Non-Dispersive Infrared Detection (NDIR) Continuous Collection (Dilute Exhaust Only) As well as Tedlar TM Bag Carbon Monoxide Non-Dispersive Infrared Detection (NDIR) Continuous Collection (Dilute Exhaust Only) As well as Tedlar TM Bag Oxides of Nitrogen Heated Chemiluminescence Detection Continuous Collection (Dilute Exhaust Only) As well as Tedlar TM Bag
Total Hydrocarbons Heated Flame Ionization Detection (FID) Continuous Collection (Dilute Exhaust Only)



### 16As well as Tedlar TM Bag

Methane and Light Hydrocarbons Gas Chromatography Tedlar TM Bag

Aldehydes High Performance Liquid Chromatography (HPLC) Sep-Pak silica cartri dges coated with 2,4- dinitrophenylhydrazine (2,4-DNPH) Total Particulate Matter Mass Gravimetric EMFAB Filter



# 6.0 RESULTS

6.1 Target vs. Actual Dri ve Cycle and Duty Cycle Actual dynamometer speeds were well wit hin the tolerances based on regression analysis as specified in SAE J2711. An example of the “driven” versus “commanded” speed regression is given in Figure 11. The hybrid truck lagged during the second hill of the LA4, an d could not meet the acceleration requirement. The speed, however, remained within the tolerances.



## y = 0.9859x
R 2 

## = 0.9925

0 10 20 30 40 50 60

0 10 20 30 40 50 6 Commanded Speed [MPH]Driven Speed [MPH]



## 0

Figure 11: Example of "commanded" versus "driven" speed on the CILCC



### On the duty cycles, it was difficult to ac hieve consistent and controlled hydraulic loading according to the prescribed schedule. Examples of the pressures obtained on Duty Cycle B are given in Figures 12 and 13. Maximum pressures

17

### occasionally reached 1900 PSI as required by the time vs. pressure schedule, but were typically between 1400 and 1700 PSI. Also, it was not possible to generate the lower pressure at the end of Duty Cycle B with the hybrid because the “low-idle” option was not available. These differences must be taken into account when comparing results to those of the SwRI utility truck tests [3], where an auxiliary hydraulic loading tool was used to simulate operation of the lift arm in a controlled manner.

Duty B - Conventional

0 200 400 600 800 1000 1200 1400 1600 1800 2000

0 200 400 600 800 1000 1200 1400 1600 1800 Time [sec]Pressure [PSI] Run 1
Run 2 Run 3 Cycle

Figure 12: Target vs. Actual Duty Cycle B Conventional



### 18Duty B - Hybrid

0 200 400 600 800 1000 1200 1400 1600 1800 2000

0 200 400 600 800 1000 1200 1400 1600 1800 Time [sec]Pressure [PSI] Run 1
Run 2 Run 3 Cycle

Figure 13: Target vs. Actual Duty Cycle B Hybrid



### 6.2 Drive Cycle Results Emissions and fuel consumpt ion results for the drive cycles are given in the following Tables and Figures. State of char ge (SOC) at the start and end of each test, as well as the battery net energy change (NEC), total cycle energy (TCE) and the NEC/TCE ratio are also provided in the tables. For the drive cycles, the NEC/TCE was always within the SAE J27 11 tolerance of 1%, and therefore no fuel consumption or emission rate corrections were made.

Table 5: Emissions and Fuel Consumption over the CILCC

CO (g/mi) Nox (g/mi) HC (g/mi) PM (g/mi) CO2 (g/mi) FC (L/100km) FC (mpg) NEC/TCE (%) TCE (kWh) Batt. NEC (kWh) SOC Start (%) SOC End (%) Warm Up 2.58 11.10 0.19 na 1368.09 31.7 7.4 - - - - - Run 1 2.33 7.96 0.22 0.065 1232.21 28.6 8.2 - - - - - Run 2 2.42 7.86 0.17 0.070 1179.80 27.4 8.6 - - - - - Run 3 2.41 8.54 0.25 0.064 1225.26 28.4 8.3 - - - - - AVE 2.38 8.12 0.21 0.066 1212.42 28.13 8.4 - - - - - CILCC Conv.

COV (%) 2 5 19 5 2 2 2 - - - - - Warm Up 4.91 5.00 0.34 na 1138.85 26.5 8.9 -0.24 52.07 -0.13 47.6 40.8

Run 1 2.01 6.22 0.28 0.099 1076.31 25.0 9.4 -0.05 49.52 -0.02 40.8 39.6

Run 2 1.93 6.37 0.29 0.083 1069.03 24.8 9.5 0.00 48.85 0.00 39.6 39.6

Run 3 1.99 6.08 0.28 0.088 1058.67 24.6 9.6 0.02 48.09 0.01 39.6 40.0

AVE 1.98 6.22 0.28 0.090 1068.00 24.78 9.49 CILCC Hybrid

COV (%) 2 2 3 9 1 1 1



### 19Table 6: Emissions and fuel consumption over the UDDS

CO (g/mi) Nox (g/mi) HC (g/mi) PM (g/mi) CO2 (g/mi) FC (L/100 km) FC (mp g) NEC/ TCE (%) TCE (kWh) Batt. NEC (kWh) SOC start (%) SOC end (%)
Warm Up 0.45 9.03 0.24 na 1424.48 33.0 7.1 - - - - - Run 1 1.55 6.97 0.19 0.133 1363.59 31.6 7.4 - - - - - Run 2 1.53 6.56 0.19 0.115 1326.39 30.7 7.7 - - - - - Run 3 1.48 6.59 0.17 0.130 1338.65 31.0 7.6 - - - - - AVE 1.52 6.70 0.18 0.126 1342.88 31.1 7.6 - - - - - UDDS Conv. 22 o C

COV (%) 2 3 6 8 1 1 1 - - - - - Warm Up 1.43 5.79 0.24 0.16 1217.60 28.2 8.3 0.30 49.10 0.15 40.8 48.8

Run 1 1.43 6.02 0.22 0.13 1232.73 28.6 8.2 0.00 49.89 0.00 48.8 48.8

Run 2 1.40 5.91 0.20 0.13 1254.61 29.1 8.1 0.00 50.85 0.00 50.8 50.8

AVE 1.41 5.97 0.21 0.130 1243.67 28.81 8.16 UDDS Hybri d 22 o C
COV (%) 2 1 7 2 1 1 1

Table 7: Emissions and fuel consumption over the LA4 cycle

CO (g/mi) Nox (g/mi) HC (g/mi) PM (g/mi) CO2 (g/mi) FC (L/100 km) FC (mpg) NEC/TCE (%) TCE (kWh) Battery NEC (kWh) SOC start (%) SOC end (%)

Warm Up 1.70 7.63 0.29 na 1370.0 31.8 7.4 - - - - - Run 1 1.57 6.78 0.22 0.119 1334.2 30.9 7.6 - - - - - Run 2 1.53 7.30 0.22 0.108 1335.8 30.9 7.6 - - - - - AVE 1.55 7.04 0.22 0.113 1335.0 30.93 7.6 - - - - - LA4 Conv.

COV (%) 2 5 0 7 0 0 0 - - - - - Warm Up 1.55 7.55 0.25 na 1256.9 29.1 8.1 1.05 37.01 0.39 36.8 57.6

Run 1 1.46 7.78 0.22 0.107 1243.6 28.8 8.2 0.25 33.54 0.08 53.6 58.0

Run 2 1.37 7.84 0.21 0.102 1219.7 28.3 8.3 0.00 33.20 0.00 57.6 57.6

Run 3 1.37 7.84 0.21 na 1219.7 28.3 8.3 0.00 32.88 0.00 57.6 57.6

AVE 1.40 7.82 0.22 0.105 1227.7 28.44 8.27 LA4 Hybrid

COV (%) 4 0 2 3 1 1 1



### 20Table 8: Emissions and fuel consumption over the UDDS at -7 o C

CO (g/mi) Nox (g/mi) HC (g/mi) PM (g/mi) CO2 (g/mi) FC (L/100km) FC (mpg) NEC/TCE (%) TCE (kWh) Battery NEC (kWh) SOC start (%) SOC end (%)

Warm Up 3.34 14.31 0.44 na 1604.72 37.2 6.3 - - - - - Run 1 1.96 6.59 0.29 0.098 1394.65 32.3 7.3 - - - - - Run 2 1.98 6.73 0.28 0.085 1383.46 32.1 7.3 - - - - - Run 3 1.98 6.35 0.27 0.085 1359.47 31.5 7.5 - - - - - AVE 1.98 6.56 0.28 0.089 1379.19 31.97 7.4 - - - - - UDDS Conventional -7 o C

COV (%) 1 3 5 9 1 1 1 - - - - - Warm Up 2.36 6.92 0.52 na 1352.16 31.4 7.5 -0.04 55.89 -0.02 50.8 49.6

Run 1 1.55 6.74 0.26 0.09 1249.89 29.0 8.1 0.09 50.78 0.04 49.6 52.0

Run 2 1.61 6.64 0.26 0.08 1217.17 28.2 8.3 -0.06 49.34 -0.03 51.6 50.0

AVE 1.58 6.69 0.26 0.084 1233.53 28.59 8.23 UDDS Hybrid -7 o C

COV (%) 3 1 0 9 2 2 2

Table 9: Emissions and fuel consumption with 10% reduction in road load over the UDDS

CO (g/mi) Nox (g/mi) HC (g/mi) PM (g/mi) CO2 (g/mi) FC (L/100km) FC (mpg) NEC/TCE (%) TCE (kWh) Battery NEC (kWh) SOC start (%) SOC end (%)

Warm Up 1.39 5.90 0.23 0.115 1130.66 26.2 9.0 -0.44 46.09 -0.20 57.6 46.8

Run 1 1.40 5.94 0.22 0.102 1124.90 26.1 9.0 0.13 45.77 0.06 46.8 50.0

Run 2 1.41 5.79 0.22 0.098 1133.01 26.3 9.0 -0.06 46.10 -0.03 49.6 48.0

AVE 1.40 5.87 0.22 0.100 1128.96 26.16 8.99 Hybrid 10% reduced load
COV (%) 1 2 1 3 1 1 1



### 210 5 10 15 20 25 30 35

CILCC UDDS LA4Fuel Consumption (L/100km) Conventional Hybrid Hybrid Reduced Road Load Conventional -7C Hybrid -7C

NA NA NA NA

Figure 14: Average fuel consumption ± 1 st andard deviation on CILCC, UDDS, and LA4 drive cycles

0 0.5

1 1.5

2 2.5

3

CILCC UDDS LA4Emission Rate (g/mi) Conventional Hybrid Hybrid Reduced Road Load Conventional -7C Hybrid -7C

NA NA NA NA

Figure 15: Average CO emission rate ± 1 st andard deviation on CILCC, UDDS, and LA4 drive cycles



### 220 0.05

0.1 0.15

0.2 0.25

0.3 0.35

CILCC UDDS LA4Emission Rate (g/mi) Conventional Hybrid Hybrid Reduced Road Load Conventional -7C Hybrid -7C

NA NA NA NA

Figure 16: Average HC emission rate ± 1 sta ndard deviation on CILCC, UDDS, and LA4 drive cycles

0 1 2 3 4 5 6 7 8 9

CILCC UDDS LA4Emission Rate (g/mi) Conventional Hybrid Hybrid Reduced Road Load Conventional -7C Hybrid -7C

NA NA NA NA

Figure 17: Average NOx emission rate ± 1 st andard deviation on CILCC, UDDS, and LA4 drive cycles



### 230 0.02 0.04 0.06 0.08

0.1 0.12 0.14 0.16

CILCC UDDS LA4Emission Rate (g/mi) Conventional Hybrid Hybrid Reduced Road Load Conventional -7C Hybrid -7C

NA NA NA NA

Figure 18: Average PM emission rate ± 1 standard deviation on CILCC, UDDS, and LA4 drive cycles



### 6.3 Duty cycle and idle results Emission rates and fuel consumption results for Duty Cycles A and B, as well as the 10 minute idle tests, are shown in the following tables. During the duty load cycles, the hybrid battery regularly dep leted to approximately 22% SOC as electrical energy was used to operate the hydraulic lift arm. Once the SOC reached this lower limit, the engine turned on and the battery was charged to approximately 69% SOC. As a result of this large swing in SOC, the battery NEC for the duty load cycle was as high as 3.4% of the total cycle energy. SOC corrections were performed according to SAEJ2711, and the linear “best fits” are plotted in Figures 20-25. The corrected values are presented in the tables below, except in cases where the coefficient of determination (R 2 

### ) was less than 0.8. This was the case for the CO and PM emission rates on each duty cycle. It is interesting to note that both THC and NO x emission rates appear to increase with greater electrical ener gy use. Unfortunately, of the three Duty Cycle A repeats and three Duty C ycle B repeats, only one te st ended with a negative battery NEC (battery depletion). Both negative and positive battery NEC results are required for linear interpolation (as opp osed to extrapolation) of the zero net energy change result. In future, becaus e interpolated data is generally more robust than extrapolated data, greater care should be taken to ensure both negative and positive NEC on the duty cycle repeats.

24

### Considering that the net energy change was not always well correlated to the emission rate, and that sometimes trends were not as expected, it may not always be appropriate to assume a linear relationship between emission rate and net energy change. While higher fuel c onsumption may contribute to a higher emission rate, other factors such as temp eratures of engine and emission control technologies, and efficient operation of th e engine will also play a role. While hybrid systems may reduce emissions through reduced fuel consumption, emissions may increase due to other fa ctors, and the relationship may not always be linear. In such cases, the c oefficient of determination may be low and the SOC correction is not possible.

Table 10: Emissions and Fuel Consumption over Duty Cycle A

CO (g/hr) Nox (g/hr) HC (g/hr) PM (g/hr) CO2 (g/hr) FC (kg/h) NEC/ TCE (%) TCE (kWh) Battery NEC (kWh) SOC start SOC end

Run 1 40.40 103.70 1.88 0.37 9606.88 3.046 - - - - - Run 2 38.62 111.46 4.46 0.40 9481.94 3.009 - - - - - Run 3 38.58 110.20 5.40 0.54 9384.02 2.979 - - - - - AVE 39.2 108.45 3.91 0.44 9490.95 3.01 - - - - - Conventional

COV (%) 3 4 47 21 1 1 - - - - - Run 1 7.04 16.28 1.26 0.00 2226.52 0.706 -0.16 4.59 -0.01 24.4 24.0

Run 2 7.04 14.16 0.50 0.00 2466.68 0.781 2.84 4.74 0.13 60.8 68.0

Run 3 7.24 15.16 0.76 0.00 2610.32 0.826 2.67 4.77 0.13 58.0 64.8

AVE 7.11 b 16.2 a 1.23 a 0.00 b 2247.4 a 0.71 a Hybrid

COV (%) 2 7 46 8 8 8

a corrected emission rate, b correction required but not possible

Table 11: Emissions and Fuel Consumption over Duty Cycle B

CO (g/hr) Nox (g/hr) HC (g/hr) PM (g/hr) CO2 (g/hr) FC (kg/h) NEC/TCE (%) TCE (kWh) Battery NEC (kWh) SOC start SOC end

Run 1 38.42 91.92 5.88 0.50 8883.60 2.822 - - - - - Run 2 37.90 91.56 5.88 0.72 8795.22 2.794 - - - - - Run 3 37.58 93.32 5.82 0.86 9122.54 2.896 - - - - - AVE 37.97 92.27 5.86 0.69 8933.79 2.84 - - - - - Conventional

COV (%) 1 1 1 26 2 2 - - - - -
Run 1 6.40 24.96 1.22 0.00 2128.34 0.674 1.22 4.90 0.06 63.6 66.8

Run 2 6.34 19.00 0.92 0.00 2464.46 0.780 3.10 4.83 0.15 58.0 66.0

Run 3 6.50 16.34 0.94 0.00 2472.66 0.783 3.43 4.80 0.16 34.0 42.8

AVE 6.41 b 29.67 a 1.39 a 0.00 b 1925.4 a 0.61 a Hybrid

COV (%) 1 22 16 7 8 8

a corrected emission rate, b correction required but not possible



### 25Table 12: Emissions and fuel consumption during a 10 minute idle

Temp CO (g/hr) Nox(g/hr) HC (g/hr) PM (g/hr) CO2 (g/hr) FC (L/hr) FC (kg/h) NEC/ TCE (%) TCE (kWh) Battery NEC (kWh) SOC start SO C

en d

Conv. 22C 17.65 114.12 0.97 0.283 6060.72 2.266 1.918 - - - - - Hybrid 22C 18.83 93.94 1.61 0.000 5095.03 1.908 1.615 0.00 3.18 0.00 38.0 38. 0
Conv. -7C 40.23 85.16 2.70 0.682 5016.93 1.893 1.602 - - - - - Hybrid -7C 45.64 68.98 3.99 0.001 4340.25 1.646 1.393 0.00 2.74 0.00 38.8 38. 8

Duty Cycles and Idle

0 2 4 6 8 10 12

CO/10 Nox/10 HC PM Fuel Consumptionemission rate [g/hr]fuel consumption [kg/hr] Duty A Conv. Duty B Conv. Idle Conv. Idle Conv. -7C Duty A Hybrid Duty B Hybrid Idle Hybrid

Figure 19: Duty cycle and idle results, SOC corrected as necessary



### 26Duty Cycle Fuel Consumption Correction

y = 0.0007x + 0.7122
R 2 = 0.8255

y = 0.0011x + 0.6107
R 2 = 0.9878

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

-50 0 50 100 150 200 NEC (Wh)Fuel Consumption (kg/hr)

Duty A FC Duty B FC Linear (Duty A FC) Linear (Duty B FC)

Figure 20: Duty cycle fuel consumption correction

Duty CO2 Consumption Correction

y = 2.2076x + 2247.4
R 2 = 0.8291

y = 3.4473x + 1925.4
R 2 = 0.9876

0 500 1000 1500 2000 2500 3000

-50 0 50 100 150 200 NEC (Wh)Emission Rate (g/hr)

Duty A CO2 Duty B CO2 Linear (Duty A CO2) Linear (Duty B CO2)

Figure 21: Duty cycle CO2 emission rate correction



### 27Duty Cycle CO Correction

y = 0.0007x + 7.0505
R 2 = 0.2106

y = 0.0004x + 6.3649
R 2 = 0.0742

6.20 6.30 6.40 6.50 6.60 6.70 6.80 6.90 7.00 7.10 7.20 7.30

-50 0 50 100 150 200 NEC (Wh)Emission Rate (g/hr)

Duty A CO Duty B CO Linear (Duty A CO) Linear (Duty B CO)

Figure 22: Duty cycle CO emission rate correction

Duty Cycle THC Correction

y = -0.0046x + 1.2315
R 2 = 0.9146 y = -0.0029x + 1.3891
R 2 = 0.9635

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

-50 0 50 100 150 200 NEC (Wh)Emission Rate (g/hr)

Duty A HC Duty B HC Linear (Duty A HC) Linear (Duty B HC)

Figure 23: Duty cycle HC emission rate correction



### 28Duty Cycle NOx Correction

y = -0.012x + 16.215
R 2 = 0.8154 y = -0.0768x + 29.67
R 2 = 0.9702

0.00 5.00 10.00 15.00 20.00 25.00 30.00

-50 0 50 100 150 200 NEC (Wh)Emission Rate (g/hr)

Duty A NOx Duty B NOx Linear (Duty A NOx) Linear (Duty B NOx)

Figure 24: Duty cycle NOx emission rate correction

Duty Cycle PM Correction

y = -1E-07x + 0.0002
R 2 = 0.4245

y = -1E-07x + 0.0002
R 2 = 0.3172

0.0E+00 2.0E-05 4.0E-05 6.0E-05 8.0E-05 1.0E-04 1.2E-04 1.4E-04 1.6E-04 1.8E-04 2.0E-04

-50 0 50 100 150 200 NEC (Wh)Emission Rate (g/hr)

Duty A PM Duty B PM Linear (Duty A PM) Linear (Duty B PM)

Figure 25: Duty cycle PM emission rate correction



### 29

### 6.4 Sample Size Calculation and StatisticsThe criterion for determining that a vehicle meets the SmartWay performancebased designation is an 80% pr obability that the results ex ceed the fuel efficiency designation by an amount equal to the lower tail of the 95% confidence interval of the test measurements. Where low em ission reductions / fuel efficiency improvements are expected and/or measurem ents have high variability, more test repeats will be required.

Appendix I of the SmartWay test protocol draft gives a method for calculating an appropriate sample size for detection of a specified emission reduction or fuel efficiency improvement. The sample size requirement is highly dependent on the variability in the data. The coefficients of variance (COVs) obtained in this study over repeats of each test condition are summarized in Table 13 . When an SOC correction was performed and the coefficient of determination was greater than 0.8, COVs were calculated using the standard error determined from the regression analysis. These are shown in bold. When the overall pollutant emission rate was low, as was the ca se for PM and HC on some cycles, the relative uncertainty in the measurement was increas ed, resulting in a higher COV.

Table 13: Coefficients of variance (%) summary
CO NOx HC PM CO2 FC FE
CILCC 2 5 19 5 2 2 2 UDDS 2 3 6 8 1 1 1
LA4 2 5 0 7 0 0 0 UDDS Cold 1 3 5 9 1 1 1 Duty A 3 4 47 21 1 1 na Conv.

Duty B 1 1 1 26 2 2 na CILCC 2 2 3 9 1 1 1 UDDS 2 1 7 2 1 1 1
LA4 4 0 2 3 1 1 1 UDDS Cold 3 1 0 9 2 2 2 Duty A 2 7 31 8 8 8 na Hybrid

Duty B 1 15 13 7 4 4 na



### Given the actual coefficients of varianc e observed in this test program, the minimum emission reductions and fuel efficiency improvements that could be detected using three test repeats are given in Table 15. This table will be useful in designing test plans, a ssuming future COVs are similar to those observed in this study. Where an emission reduction or fuel efficiency improvement is expected to be lower than the table value, it would be wise to plan to conduct more test repeats to ensure statistical si gnificance. For instanc e, if a technology is expected to reduce the HC emission rate by less than 25% on the CILCC, more than three test repeats will be needed in or der to detect the reduction with the desired confidence level.

30Table 14: Minimum reductions and improvements with 80% probability of detection at the 95% confidence level using 3 repeats

Minimum reduction detectable (%) Minimum improvement

detectable (%)
CO NO x HC PM CO 2 FC FE CILCC 6 9 25 18 5 5 5 UDDS 5 6 15 12 4 4 4
LA4 9 9 4 12 2 2 2 UDDS Cold 5 6 8 20 4 4 4 Duty A 6 14 62 29 14 14 na Duty B 3 37 22 33 8 8 na



### 6.5 Fuel Efficiency Improvements and Emission Reductions

Fuel efficiency improvements and emission reductions (Table 16, Figures 26-30) provided by the hybrid power train were most pronounced during the duty load cycles. Emissions of CO, CO 2 

### , NO x 

### , and HC were reduced by 74 to 100 % and fuel consumption was reduced by 74%. Th is reduction is lower than the 87% and 91% improvements reported by SwRI [3]. It should be noted tha t, as described in Section 6.1, the load vs. time schedule wa s not followed precis ely. The auxiliary hydraulic circuit used by SwRI was able to follow the schedule more accurately.

Fuel efficiency improvements and emission reductions were less distinct on the driving cycles. Of the driving cycles, t he CILCC provided for the greatest fuel efficiency improvement, with the hybrid sho wing a fuel efficien cy increase of 13% over the conventional truck. Again, this is lowe r than the improvement observed in the SwRI study [3]. On the UDDS and LA4 cycles, fuel efficiency improvements were 8% and 10% respectively.

Emission reductions on the driving cycles were varied, and in fact, the hybrid often showed emission increases over t he conventional truck. These are shown in the tables below in bold red type as n egative reductions. It is important to note that in almost all cases where the hy brid system appeared to cause emission increases, the increase was insi gnificant. This is best illu strated in Figures 26 to 30, which show the fuel efficiency improvements and emission reductions bracketed by upper and lower bounds of t he 90% confidence interval, based on a two-tailed t-test. Negative emission reduc tions almost always have a confidence interval that crosses zero (no impact of hybrid system). Exceptions are the THC and PM emission rates over the CILCC, where the hybrid system did cause an increased emission rate.

31

### Table 16 gives the lower bound of the 95% c onfidence interval based on a onetailed t-test as described in Appendix J of the draft SmartWay test protocol.

The final rows in Table 16 and 17 ar e not a comparison between conventional and hybrid systems, but bet ween UDDS tests on the hybrid truck with the appropriate road load settings, and with a 10% reduced road load. When road load was reduced by 10%, fuel efficien cy was improved by 10%. The change in road load had essentially no impact on t he emission rates of CO, NOx and HC. The PM emission rate, however, was reduced by 23% due to the lower road load.

Table 15: Emission reductions and fuel efficiency improvements

Emission and Fuel Consumption Reductions Fuel Efficiency Improvement

Cycle CO NOx HC PM CO2 FC FE

CILCC 0.17 0.23 -0.34 -0.35 0.12 0.12 0.13 UDDS 0.07 0.11 -0.13 -0.03 0.07 0.07 0.08

LA4 0.10 -0.11 0.01 0.08 0.08 0.08 0.09 Duty A 0.82 0.86 0.84 1.00 0.74 0.74 na Duty B 0.83 0.78 0.82 1.00 0.74 0.74 na UDDS -7degC 0.20 -0.02 0.09 0.05 0.11 0.11 0.12 Hybrid with 10% Road Load Reduction 0.00 0.02 -0.08 0.23 0.09 0.09 0.10

Table 16: Lower bound of the 95% confidence interval on emission reductions and fuel efficiency improvements

Emission and Fuel Consumption Reductions Fuel Efficiency Improvement Cycle CO NOx HC PM CO2 FC FE
CILCC 0.14 0.18 -0.56 -0.53 0.08 0.08 0.10 UDDS 0.04 0.06 -0.31 -0.17 0.05 0.05 0.04

LA4 0.04 -0.32 -0.03 -0.24 0.06 0.06 0.07 Duty A 0.81 0.85 0.76 1.00 0.71 0.71 na Duty B 0.81 0.73 0.79 1.00 0.73 0.73 na UDDS -7degC 0.11 -0.06 0.01 -0.18 0.07 0.07 0.01 Hybrid with 10% Road Load Reduction -0.07 -0.03 -0.36 0.18 0.04 0.04 0.04



### 32

# Fuel Efficiency Improvement

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Fuel Efficiency Improvement Ratio



## CILCC UDDS LA4 Duty B Duty A UDDS -7degC -10% load

Figure 26: Fuel efficiency improvement with 90% confidence interval



# CO Emission Rate Reduction

-0.2 -0.1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Emission Reduction Ratio



## CILCC UDDS LA4 Duty B Duty A UDDS -7degC -10% load

Figure 27: Reduction in CO emission rate with 90% confidence interval



### 33

## THC Emission Rate Reduction

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Emission Reduction Ratio



## CILCC UDDS LA4 Duty B Duty A UDDS -7degC -10% load

Figure 28: Reduction in THC emission rate with 90% confidence interval



## NOx Emission Rate Reduction

-0.4 -0.3 -0.2 -0.1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Emission Reduction Ratio



## CILCC UDDS LA4 Duty B Duty A UDDS -7degC -10% load

Figure 29: Reduction in NOx emission rate with 90% confidence interval



### 34

## PM Emission Rate Reduction

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Emission Reduction Ratio



## CILCC UDDS LA4 Duty B Duty A UDDS -7degC -10% load

Figure 30: Reduction in PM emission rate with 90% confidence interval



### 6.6 Cold Temperature Impacts

Cold temperature impacts were exam ined over the hea vy duty UDDS. Tests were performed at 22 o 

### C and -7 o 

### C, and all tests were preceded by a warm-up HD UDDS. The effects are displayed in Fi gure 31. The cold am bient temperature had no significant impact on fuel consumption or CO 2 

### emission rate after warmup. There were, however, significant effect s on pollutant emission rates. At cold ambient temperature the CO emissi on rate increased by 30% for the conventional truck, and by 12% for the hy brid truck. The THC emission rate increased by 54% for the conventional tru ck, and by 24% for the hybrid truck. The NOx emission rate increased by 12% for the hybrid, but showed no change for the conventional vehicle. The PM emission rate was decreased at cold ambient temperature relative to standar d temperature. It s hould be noted that with only two UDDS test repeats on the hy brid at each temperature, the 90% confidence intervals on the THC and PM emission rates were particularly wide. More repeats are needed in future.

35

# Emission Increases at -7 o 

# C Ambient Temperature

-0.8 -0.6 -0.4 -0.2

0.0 0.2 0.4 0.6 0.8Emission Increase 

# Conventional Hybrid

CO NO x 

## THC PM CO 2

Figure 31: Cold temperature impacts on pollutant emission rates (with 90% confidence interval)


# 7.0 CONCLUSIONS AND RECOMMENDATIONS

Benefits of Hybrid Technology Benefits of adopting this hy brid system, based on test s conducted according to the proposed SmartWay test protocol, include:

During CILCC driving; (1) a fuel efficiency improvement of 13 ± 3% (2) a CO 2 

### emission rate reduction of 12 ± 4% (3) a NOx emission rate reduction of 23 ± 5% (4) a CO emission rate reduction of 17 ± 3%

and during hydraulic loading; (1) a fuel consumption reduction of 74 ± 3% (duty A) and 74 ± 2% (duty B) (2) a CO 2 

### emission rate reduction of 74 ± 3% (duty A) and 74 ± 2% (duty B) (3) a NOx emission rate reduction of 86 ± 1% (duty A) and 78 ± 6% (duty B) (4) a CO emission rate reduction of 82 ± 1% (duty A) and 83 ± 1% (duty B) (5) a THC emission rate reduction of 84 ± 9% (duty A) and 82 ± 4% (duty B) (6) a PM emission rate reduction of 100%

Clearly, the benefits of hybrid technology are considerable, and of greatest magnitude during hydraulic l oading duty operation. Ther e were, however, several

36

### instances where the hybrid technology showed a disadvantage relative to the conventional system. The hy brid system caused THC and PM emission rates to increase during driving by 34% ± 22% and 35% ± 18% respectively. It is important to note that emission rates are dependent not only on the amount of fuel consumed, but on the engine temper ature and operation of after-treatment technologies. In future, mo re test repeats should be used to reduce the width of the confidence interval on T HC and PM emission rates.

While the CILCC is currently the recommended test cycle of the proposed SmartWay Test Protocol, other drive cycl es may yield significantly different results. For example, the fuel effici ency improvement on t he UDDS was 8% ± 4%, and on the LA4 it was 10% ± 2%. Th ese improvements are less substantial than those of the CILCC.

Test to test variability and statistics A table of coefficients of variance was pr esented in Section 6. 4. These COVs can be used to determine the required number of driving test repeats for a given expected fuel efficiency improvement and emission reduction. The net electrical energy changes on the drive cycles were within the SAE J27 11 tolerance, and thus corrections were not required.

Unlike for the drive cycles, the net elec trical energy chan ges were highly elevated on the duty cycles as the ba ttery charged to approximately 69% and depleted to 22%. For cycles with these high net energy changes, where SOC correction is required, the standard e rror on the reported value must be determined from regression analysis. It is recommended that such a method be described in the statistics secti on of the SmartWay Protocol.

Typical CO 2 

### Consumption Rate The CO 2 

### emission rates of both conventional and hybrid trucks under the various driving conditions are given in Table 17

.
Table 17: CO2 Emission Rate Summary CILCC (g/mi) HD UDDS (g/mi) LA4 (g/mi) HD UDDS -7degC (g/mi) Duty A (g/hr) Duty B (g/hr)

Conventional 1212 1343 1335 1379 9491 8934 Hybrid 1068 1244 1228 1234 2247 a 1925 a

a SOC corrected



### These emission rates can be used to help characterize the typical CO 2 

### emission rates of conventional and hybrid utility trucks.

Cold Temperature Impacts Because all tests were perform ed after a warm-up cycle, the -7 o 

### C ambient temperature had little effect on fuel effi ciency. There were, however, substantial

37

### impacts on emission rates of CO, and NOx. More repeats are needed in future to reduce the width of the confidence in terval on THC and PM emission impacts.

Road Load Impacts When road load was reduced by 10%, fuel efficiency wa s improved by 10%. The change in road load di d not have a signif icant impact on the emission rates of CO, NOx and HC. The PM emission rate, however, was reduced by 23% due to the lower road load. This result offers insight into the consequences of any inaccuracies in the coast down procedure.

Recommendations It is recommended that the following changes/additions be made to the SmartWay Test Protocol: (1) Considering the varyi ng results obtained under diffe rent driving conditions, care should be taken when selecting the drive cycle to ensure it is representative of real world operation. Because t he CILCC is 53 minutes long and repetitive, it is difficult for one driv er to perform the minimum 4 repeats (warm-up/practice + 3 repeats) . It is the ERMS’s recommendation that the cycle be used for dynamome ter testing only until better data (perhaps from real world logging of v ehicle operation) bec omes available. (2) Indicate specifica lly that augmented braking should be disabled for dynamometer testing of hybrid vehicles. (3) When testing on a two-wheel (singl e roll) dynamometer, ABS fault codes should be disabled. (4) A note addressing the use of regr ession analysis to determine standard error when SOC correction is required should be added to the statistical methods proposed in the protocol.

During the second round of te sting, it is recommended t hat the following changes be made to the program: (1) Minimum of three repeats always in order to reduce the width of the confidence interval (2) Direct measurement of current (and possibly volt age) from the hybrid battery in order to verify the SO C readings from the J1939 device. (3) Reduced temperature of -18 o 

### C to investigate sensitivity of emissions and fuel consumption to cold climate (4) On-road coast down data with resoluti on of 0.1 mph, and all coast downs to a speed less then 5.0 mph if possible.

Additional changes to the program may be made upon recommendation by the U.S. EPA.



# REFERENCES
[1] United States Environmental Protection Agency, “SmartWay Fuel Efficiency Test Protocol for Medium and Heavy Duty Vehicles, Working Draft”, EPA420-P-07-0 03. (November 2007).

38

### [2] Society of Automotive Engineers, “Recommended practice for measuring fuel economy and emissions of hybr id-electric and conventional heavyduty vehicles” Surface Vehicle Recommended Practice No. SAE - J2711, (2002).

[3] Southwest Research Institute, “E missions and Fuel Economy Testing of Three Utility Trucks”, SwRI Project No. 03.11602, (2007).

39

# Appendix A – Vehicle Specifications

Table A-1: Conventi onal Utility Truck
ITEM DATA ERMS Vehicle ID#: ER2008-038 VEHICLE VIN 1HTMMAAL67H320541 VEHICLE TYPE Utility Truck VEHICLE MANUF AND MAKE International VEHICLE MODEL 4300SBA 4X2 NUMBER OF AXLES 2 (1 Front, 1 Rear) NUMBER OF DRIVE AXLES 1 (Rear) TRANS TYPE AND # OF GEARS Alison 5-Speed Automatic Transmission VEHICLE BUILD DATE Jan. 9, 2006 GVWR 25,999 EXHAUST PIPE DIAMETER 4” STARTING ODOMETER 14,200 ENGINE FAMILY ON LABEL 6NVXH0466AEA ENGINE MANUFACTURER Navistar ENGINE MODEL D210 SERIAL NUMBER 466MM2U2101062 ENGINE BUILD DATE n/a HP RATING ON LABEL 210 RATED SPEED 2300 TORQUE RATING 520 TORQUE SPEED 1400 EMISSION CONTROLS Electronic Inje ction, EGR, Oxidation Catalyst MAKE AND DESCRIPTION OF BODY Altec L42A Aerial Boom OTHER BODY INFORMATION Boom Platform Capacity - 400 lbs OTHER BODY INFORMATION Boom Platform Height - 42 ft OTHER BODY INFORMATION Max. Hydraulic System Pressure Setting - 3000 PSI OTHER BODY INFORMATION Throttle Controls - High Idle, Low Idle AMOUNT OF PAYLOAD n/a TOTAL WEIGHT OF VEHICLE AND BODY 20,242 FUEL DESCRIPTION ULSD VEHICLE SPEED GOVERNED Yes, 65 MPH Tire Tread Depth (measur ed from outside --> in) Section 1 Left Front 11, 14, 11 Right Front 10, 11, 12 Left Rear 12, 11, 15, 14, 13, 12 Right Rear 11, 10, 12, 12, 11, 10 Section 2 Left Front 14, 12, 15 Right Front 14, 11, 12 Left Rear 12, 11, 12, 13, 13, 11 Right Rear 11, 10, 14, 12, 10, 9 Section 3 Left Front 11, 11, 11 Right Front 14, 11, 12 Left Rear 11, 11, 14, 13, 12, 10 Right Rear 11, 11, 12, 12, 12, 11



### 40

### Table A-2: Hybrid Utility Truck
ITEM DATA ERMS Vehicle ID#: ER2008-039 VEHICLE VIN 1HTMMAANX6H152743 VEHICLE TYPE Utility Truck VEHICLE MANUF AND MAKE International VEHICLE MODEL 4300SBA 4X2 NUMBER OF AXLES 2 (1 Front, 1 Rear) NUMBER OF DRIVE AXLES 1 (Rear) TRANS TYPE AND # OF GEARS Fuller 6-Speed Automated Manual Transmission VEHICLE BUILD DATE Apr. 19, 2005 GVWR 25,999 EXHAUST PIPE DIAMETER 4” STARTING ODOMETER 23,738 ENGINE FAMILY ON LABEL 5NVXH0466AEA ENGINE MANUFACTURER Navistar ENGINE MODEL D225CFF SERIAL NUMBER 1858217C1 ENGINE BUILD DATE n/a HP RATING ON LABEL 225 RATED SPEED 2300 TORQUE RATING 560 TORQUE SPEED 1400 EMISSION CONTROLS Electronic Inje ction, EGR, Oxidation Catalyst MAKE AND DESCRIPTION OF BODY Altec L42A Aerial Boom OTHER BODY INFORMATION Boom Platform Capacity - 300 lbs OTHER BODY INFORMATION Boom Platform Height - 42 ft OTHER BODY INFORMATION Max. Hydraulic System Pressure Setting - 3000 PSI OTHER BODY INFORMATION Throttle C ontrols - High Idle, Electric PTO AMOUNT OF PAYLOAD n/a TOTAL WEIGHT OF VEHICLE AND BODY 23,062 FUEL DESCRIPTION ULSD VEHICLE SPEED GOVERNED Yes, 65 MPH Tire Tread Depth (measur ed from outside --> in) Section 1 Left Front 15, 17, 15 Right Front 15, 14, 16 Left Rear 14, 12, 14, 15, 14, 15 Right Rear 8, 9, 10, 6, 5, 6 Section 2 Left Front 18, 16, 17 Right Front 19, 14, 19 Left Rear 14, 13, 13, 15, 15, 13 Right Rear 12, 10, 12, 5, 6, 6 Section 3 Left Front 19, 18, 19 Right Front 14, 14, 18 Left Rear 13, 13, 14, 15, 15, 14 Right Rear 11, 10, 12, 6, 6, 5 Vehicle Vendor Contact Claude Masters (561-722-2776) Hybrid Drive Train Manufacturer Eaton Corporation Type of RESS 340 V DC NiMH Battery Regenerative Braking Electric Motor / Generator via Driveshaft Special features Hydraulic Boom Arm



### 41