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## DRAFT

COST-EFFECTIVENESS OF A 40% BODY AND CHASSIS

WEIGHT-REDUCTION GOAL IN LIGHT-DUTY VEHICLES

Sujit Das

Energy and Transportation Science Division Oak Ridge National Laboratory

Prepared for Lightweight Materials Office of Vehicle Technologies U. S. Department of Energy



### June 2009

OAK RIDGE NATIONAL LABORATORY Oak Ridge, Tennessee 37831 managed and operated by UT-Battelle, LLC

for the

U.S. DEPARTMENT OF ENERGY

under contract No. DE-AC05-00OR227251 Cost-Effectiveness of a 40% Body and Chassis Weight -Reduction Goal in Light-Duty Vehicles

Oak Ridge National Laboratory

June 2009

1. Background

With the recent higher gasoline prices, new emissio n and fuel economy regulations that require by 2016 a 30% reduction in CO 2 and other emissions and an average fuel economy of at least 35 mpg, the pressure to lightwe ight vehicles is stronger than ever before. The next few years will see considerable li ght-weighting across the automotive industry. Vehicle lightweighting represents one of several design approaches automakers are currently evaluating to improve fuel economy. L ightweighting is typically accomplished by downsizing, integrating parts and f unctions, substituting materials, or by combining these methods. Lightweighting Materials’ (LM’s) component of the U .S. Department of Energy’s Vehicle Technologies program focuses on the development and validation of advanced materials and manufacturing technologies to significantly reduce automotive passenger vehicle body and chassis weigh t without compromising other attributes such as safety, performance, recyclabili ty, and cost. The specific goals of LM are to develop material and manufacturing technolog ies by 2010 that, if implemented in high volume, could cost-effectively reduce the weig ht of passenger-vehicle body and chassis systems by 50% with safety, performance, an d recyclability comparable to 2002 vehicles. In order to achieve this long-term weight -reduction goal, LM has set annual intermediate weight-reduction goals, starting with 10% in FY2007, and finally achieving 50% by FY2010. This paper is a follow-on to an earl ier study which focused on the 25% body and chassis weight-reduction goal of FY2008 (D as 2008). The present study emphasizes the assessment of cost-effectiveness to achieve the desired goal of 40% body and chassis weight reduction in FY2009.

To achieve its long-term weight-reduction goal, LM has prioritized its research areas in several lightweighting materials including advanced high-strength steel, aluminum, magnesium, titanium, and composites. Composites inc lude metal-matrix materials and glass- and carbon-fiber reinforced thermosets and t hermoplastics. Over the past several years, the LM R&D portfolio has included assessment s of various lightweight body and front-end structures, such as those constructed of advanced high-strength steel, composite-intensive, and magnesium. These assessmen ts, either completed or underway, include, for example, one in which the goal is to d esign, analyze, and develop the technology for a composite-intensive, body-in-white structure that achieves a minimum of 60% weight savings over steel. Additionally, the latest LM multi-material vehicle (MMV) project aims to synthesize and demonstrate th ese various lightweight material component options in a single vehicle. Cost remains one of the major obstacles to successful market penetration of these various ligh tweight materials. Complete vehicle system-level cost estimation is essential since it captures the cost reduction potential due to both part integration and mass de-compounding ef fect. Today OEMs remain more focused on the vehicle’s retail price rather than o n vehicle life cycle cost.2

This paper provides an assessment of the cost-effec tiveness of a 40% body and chassis weight-reduction goal for FY2009.The cost-effective ness of the proposed weightreduction goal is determined based on the vehicle r etail and life cycle cost analysis of a potential lightweight material substitution scenari o in various body and chassis components to achieve the desired weight-reduction goal. Cost methodology and potential data sources for the analysis are then di scussed. Cost data collected for various vehicle components considered for achieving the wei ght reduction goal are then discussed, as are the assumptions and methodology u sed. A discussion of the results of the cost analysis of the proposed scenario is then presented, followed by conclusions.

2. Approach

2.1 Scenario Development

Cost-effectiveness of a 40% body and chassis weight -reduction goal was demonstrated based on a scenario analysis by focusing on a speci fic lightweight material type substitution at a major vehicle-component level. A representative mid-size vehicle, i.e. Honda Accord, was considered as the baseline agains t which the cost-effectiveness of weight reduction goal was determined. Due to a sign ificantly higher weight reduction goal, carbon fiber-reinforced polymer-matrix compos ites (carbon-FRPMCs) and aluminum were primarily considered for body and cha ssis applications. These two materials have the potential to achieve the desired weight-reduction goal. Only carbonFRPMCs offer the potential for greater than 50% red uction in the weight of body and chassis components while providing strength five ti mes greater than steel for structural parts. Most applications of this material have been in high-end vehicles and race cars. Aluminum use in today’s light-duty vehicles is limi ted to about 325 lbs/vehicle, mainly in castings for the powertrain (engine block, cylinder head and transmission cases) and wheels, but aluminum use could be significantly gre ater with the addition of wrought aluminum that has a weight reduction potential rang e of 30-50% compared to

conventional steel.

Table 1 shows the 40% body and chassis weight-reduc tion scenario for a mid-size passenger car considered in the cost-effectiveness analysis. The scenario focuses on a plausible specific lightweight material option (i.e ., mainly carbon-FRPMC or aluminum) at the broad component category level based on its near-term market potential to achieve the desired overall body and chassis weight reducti on goal. This scenario approach

allows determination of cost-effectiveness at a veh icle level, the context important for the actual implementation and commercialization of the lightweighting materials technologies in the market place. Specific componen ts considered under body and chassis vehicle subsystems are highlighted in Table 1 (in b old type). The potential weight reduction for each part also is given. Since most l ightweight component options considered here are yet to be commercialized, the p ercentage weight reduction assumed

in each case is based on the best estimated value a vailable in the literature today. The definitions of various vehicle components are based on the Automotive System Cost Model (ASCM, discussed below) and are provided in A ppendix A.3 Table 1. Mid-Size 40% Body& Chassis Weight Reductio n Scenario 1

SYSTEM Baseline 40% Weight Reduction Scenario

Technology Mass

(kg) Technology Mass (kg)

Powertrain

Engine V-6 3.0L DOHC
AL/AL 197 V-6 3.0L DOHC AL/AL 192

Energy Storage Lead-Acid, Standard 19 Lead-Acid, St andard 18
Fuel System Gasoline, 17 gal 83 Gasoline, 17 gal 83

Transmission Automatic (L5) 81 Automatic (L5) 79
P/T Thermal Generic (car) 29 Generic (car) 29

Driveshaft/Axle Generic 77 Generic 74

Differential Generic 25 Generic 25
Exhaust System Generic 48 Generic 48

Oil and Grease Generic 15 Generic 15

Powertrain Electronics Generic 10 Generic 10

Emission Control
Electronics Generic 10 Generic 10
Body

Body-in-White Midsize steel unibody 320 Carbon Fiber Polymer Composites (55% wt redn.) 144

Panels Stamped Steel 60 Carbon Fiber Polymer Composites (55% wt redn.) 27

Front/Rear Bumpers Sheet Steel 10 TP/Carbon Fiber (60% wt reduction) 4

Glass Conventional, 4 mm 40 Polycarbonate (25% reduction) 30

Paint Solventborne, avg color 12 Solventborne, avg color 12

Exterior Trim Generic 10 ULSAB (35% wt. reduction) 7

Body Hardware Generic 10 Generic 10 Body Sealers and
Deadners Generic 2 Generic 2

Chassis

Cradle Generic 35 Aluminum (45% wt. reduction) 19

Corner Suspension Generic 47 Aluminum (35% wt. reduction) 31

Braking System ABS 48 Aluminum (5.5% wt reduction) 45

Wheels and Tires Aluminum 15” 71 Magnesium 15" (40% wt. reduction) 59

Steering System Generic 27 Aluminum (5.5% wt. reduction) 26

Interior

Instrument Panel Generic 26 Generic 26

Trim and Insulation Generic 24 Generic 24

Door Modules Generic 28 Generic 28
Seating and Restraints Generic 66 Generic 66

HVAC Generic 22 Generic 22

Electrical 33 33
Final Assembly 40 40 Total Body & Chassis Weight (% less than baseline) 692 415 (40%)

Total Vehicle Weight 1525 1237

1 All weights in the table denote values after primary w eight savings only.4

2.1.1 Carbon-FRPMC

Application of carbon-FRPMC in automobiles is quite limited and occurs only in lowvolume niche vehicles today such as Formula 1 race cars, Mercedes-Benz McLaren SLR supercar, Mazda’s RX-8, Honda’s Legend sedan, Mitsu bishi’s Pajero SUV, and Nissan’s latest GT-R super sports car. General Motors is usi ng the Corvette ZR1 to study the feasibility of high-volume carbon-FRPMC parts, wher eas Toyota is planning to use a body frame made of this material in its 1/X concept car that will offer the same interior space as the Prius hybrid but only weigh one-third as much. Most carbon-FRPMC applications include drive shafts, spoilers, A-pill ars, underbody structures, and various body panels for high-performance, low-volume cars. Three Japanese companies, i.e., Toray Industries, Teijin, and Mitsubishi Rayon, whi ch control 70% of the global carbon fiber market, are aiming to pioneer mass production of this material for widespread use in cars. For example, Teijin who is planning to start supplying carbon-resin composites to automotive parts makers as early as 2010 via its su bsidiary Toho Tenax, is aiming to first make engine undercovers for high-range sports cars and then move towards mass market models. Toray Industries has invested in a German d eveloper of carbon-FRPMC parts for cars and trucks, and is planning to expand its sale s for automotive applications to approximately $510 million by 2015, including ultim ately mass-produce carbon-fiber parts mainly for Toyota. Honda and Nissan have simi larly joined with Toray and Mitsubishi Rayon to research new, less-expensive ca rbon fiber for cars.

To achieve a significantly higher body and chassis weight reduction goal, this analysis considers carbon-FRPMC for three major body compone nts as shown in Table 1. These three body components, body-in-White (BIW), panels, and front/rear, have been considered as the most suitable components applicat ion of this lightweight material since these components contribute more than 25% of total vehicle weight. Potential percentage weight reduction assumed for these components has b een in the mid range of 55-60%, although expected weight reduction has been reporte d to be 45-80% compared to mild steel depending on specific automotive part applica tion. For example, Focal Project 3 of the Automotive Composites Consortium (ACC)—a collab orative, pre-competitive R&D partnership of the three big OEMs and DOE—predicted a 66% BIW weight reduction with a total number of parts less than 20 by demons trating the potential on a carbon fiber B-pillar (Iobst et al. 2007). Similarly, niche vehi cles such as X-Power sports vehicles have demonstrated 70% weight reduction potential in body panels compared with steel (Marsh 2006). On the other hand, the structural com posite underbody targeted to be a part

of the United States Automotive Material Partnershi p (USAMP) Multi-Material Vehicle (MMV) project has obtained only 29% weight reductio n using carbon fabric for floors. The project’s objective, however, was to capitalize on the material’s strength to optimize the crash performance rather than to reduce weight (Berger and Jaranson 2009). In fact, carbon-FRPMC is currently not under further conside ration in the MMV project and a new project on carbon-FRPMC body structure to optim ize the weight savings potential has been under consideration for near-term funding. Use of carbon fibers in Formula 1 cars such as Mercedes McLaren SLR in monocoque desi gn is 50% lighter than steel components (Marsh 2006), and a 48% reduction in BIW mass without doors has been5

considered for a composite monocoque using various combinations of carbon and glass fibers in one of the earlier studies (Mascarin et a l. 1995).

2.1.2 Aluminum

To achieve the desired 40% body and chassis weight reduction goal, aluminum

substitution was considered in several vehicle chas sis components, as shown in Table 1, including corner suspension, cradle, braking system , and steering system. Aluminum (forged or cast) is desirable in vehicle chassis co mponents because it reduces un-sprung weight of the suspension, thereby improving overall handling performance and ride comfort. The cradle is the component assumed to hav e the most weight reduction— 45%—among the components considered here for alumin um substitution. Aluminum penetration has been relatively high in steering kn uckles, and a weight reduction in the range of 35-45% can be achieved by integrating mult iple parts into a single unit. Similarly, aluminum control arms, with a weight red uction potential of 20-30% compared to steel, have a 20% market share today. Aluminum c orner suspension substitution

assumes here both aluminum control arms and steerin g knuckles, with a combined weight reduction potential 35%.

Aluminum use has been considered for brake actuator s and steering wheel column, with an estimated weight savings potential of 30.5% and 43%, respectively (EEA 2007). However, in both cases, the substitution of a singl e component in the system achieves a relatively small weight reduction at the system lev el compared to the weight reduction achieved in the single part. The weight reduction p otential in each system is assumed to be 5.5%. Although the wheels segment has seen consistent growth in al uminum use, it is anticipated that the more aggressive weight reducti on goal will produce a shift from cast aluminum wheels to cast magnesium wheels, the latte r offering a 40% weight reduction potential compared to cast aluminum wheels (EEA 200 7). Like other lightweight materials, high production-volume cost has been the limiting factor that historically limited automotive growth. To date, an average vehi cle contains 10-12 lbs of magnesium, mostly as castings in the instrument panel beam, tr ansfer case, steering components, and radiator support. There is a great need for develop ment of wrought magnesium products and manufacturing processes to provide improved mec hanical and physical properties, crash performance, and corrosion resistance before magnesium’s use in more critical body and chassis applications can be expanded. To a chieve the total savings goal of 40% of the primary body and chassis weight, a 35% reduc tion in exterior trim weight has been assumed. This weight savings are consistent with th e target weight for the PNGV-Class vehicle which has a target weight of around 1000 kg vehicle curb mass (ULSAB-AVC 1999).

2.1.3 Secondary Weight Savings

The objective for the selection of lightweighting m aterial options for various vehicle components (as discussed above) was to achieve the primary 40% body and chassis weight-reduction goal. However, consideration of se condary weight savings in body and chassis components is important because it takes in to account the effect of primary6

savings on the powertrain, chassis, and body compon ents. The cost-effectiveness of lightweighting options depends considerably on the secondary savings since those savings helps to reduce the overall effect of highe r lightweight material cost. Powertrain resizing in secondary weight savings calculations a llows comparisons of functionally equivalent vehicle designs—a reduced vehicle weight requires a less powerful engine to achieve equivalent performance (i.e., acceleration, range etc.). Secondary weight savings have been estimated by ASCM, and those savings rela ted to the two scenarios considered here are presented in Table 2 along with other esti mated major parameters in the costeffectiveness analysis. Total secondary weight savi ngs are estimated to be 49% of primary savings and depend on the number of vehicle components considered. Most of the secondary weight savings occur in the powertrai n system and depend on the extent of powertrain downsizing assumed. Since the ASCM inclu des secondary weight savings only of major vehicle components (i.e., all chassis components and a few major powertrain and body components), the percentage tot al weight savings in this case is somewhat lower than another recent estimate (Malen and Reddy 2007).

Note: % values within parenthesis indicate savings with respect to baseline steel

With the consideration of secondary weight savings, total body and chassis weight savings are estimated to be 45.3% as shown in Table 2. There will be a decrease in powertrain weight with powertrain resizing, where e ngine power is estimated to decrease by 24%. The resulting vehicle weight reduction has been estimated to 28%. Fuel economy estimates have been based on a reasonable r ule of thumb that each one percent reduction in weight should give a 0.66 percent impr ovement in fuel economy, after a vehicle has been fully redesigned to account for th e reduced power demands of a lower mass. Combined vehicle fuel economy would increase from the baseline value of 23 mpg to 27.2 mpg with the 40% body and chassis weight-re duction goal.

Table 2. Major Parameters Considered in the Cost-E ffectiveness Analysis of the 40% Body and Chassis Weight Reducti on Goal

Parameter Baseline 40% Body and Chassis Weight Reduction Scenario Primary Body & Chassis Weight Savings NA 277 kg (40%)

Secondary Weight Savings

Body & Chassis NA 37 kg (5.3%)

Powertrain NA 98 kg

Total NA 135 kg Body & Chassis Weight 692 kg 378 kg (45%) Powertrain Weight 594 kg 485 kg (18%) Engine Power 122 kW 93 kW Final Vehicle Weight 1524 kg 1102 kg (28%) Combined Fuel Economy 23 mpg 27.2 mpg Vehicle Lifetime Operation 120,0007

2.2 Cost Estimation Methodology

As with the earlier study (Das 2008), this analysis employs the Automotive System Cost Model (ASCM), developed jointly by Oak Ridge Nation al Laboratory and Ibis Associates, Inc. in collaboration with Argonne Nati onal Laboratory, to estimate the costeffectiveness of the 40% body and chassis weight-re duction goal. ASCM estimates the vehicle-manufacturing cost at a level of five major vehicle subsystems (powertrain, chassis, body, interior, and electrical) consisting of more than thirty-five components (some components have been shown in aggregate form in Table 1 before) based on the aggregation of several components under the definit ion of Uniform Parts Grouping (UPG) generally used by the automotive industry (as listed and defined in Table 1 and Appendix A). Each component represents a specific m anufacturing technology. Vehicle retail price based on the sum of manufacturing cost (i.e., costs of components and assembly), overhead, and selling is added to vehicl e operation costs for the vehicle life cycle cost estimation. The interrelationships among vehicle subsystems and their effect on vehicle manufacturing cost are addressed, allowi ng inclusion of the impacts of secondary mass and cost savings as well. Functional interrelationships have been developed for major chassis components to estimate secondary mass savings based on first principles of physics, and using semi-empiric al and empirical information available from the literature today. The powertrain sizing ro utine in this model is based on the algorithm used in the Argonne National Laboratory’s (ANL) hybrid vehicle cost model (HEVCOST), where the power and mass projections of various powertrain components are based on component-specific power and efficienc y values, with the capability to evaluate alternative hybrid electric vehicle config urations and performance strategies (Plotkin et al. 2001). The main objective of this m odel is to facilitate estimation of vehicle-manufacturing and life-cycle costs using a uniform methodology to allow comparison of alternative advanced technologies bei ng considered for vehicles today. This cost model has been integrated into the vehicl e performance model PSAT (Powertrain System Analysis Toolkit) developed by A rgonne National Laboratory, thereby facilitating instantaneous vehicle cost est imation based on the detailed powertrain component sizing estimates by PSAT. This cost model has been used in several studies for a comparative cost assessment of different powe rtrain and body-in-white options for advanced technology vehicles (Das 2004 and 2005; Ro usseau et al. 2005).

Two types of overhead, i.e., OEM and dealer margin are added to the vehicle manufacturing cost to estimate vehicle retail price . The former is assumed to be fixed,

while the latter varied with the vehicle manufactur ing cost. Vehicle operation cost categories considered in the vehicle life cycle cos t estimation include financing, insurance, local fees, fuel, battery replacement, m aintenance, repair, and disposal. Financing, insurance, and local fees costs are dict ated by the vehicle retail price, while the fuel cost is dictated by the vehicle’s fuel eco nomy (estimates are shown in Table 2) and a gasoline price of $1.90/gallon, based on near -term price trends (EIA 2009). With the exception of maintenance and repair, all other operation cost categories vary with the two lightweighting scenarios considered here based on estimated vehicle retail price and fuel economy. Total life cycle cost is estimated as the net present value assuming total8

vehicle lifetime miles are 120,000—based based on a verage 10,000 miles driven annually and a vehicle life of 12 years—and a discount rate of 10%.

2.3 Component Cost Data

Component technology cost data used in the analysis are mainly based on the latest estimates developed by Ibis Associates, Inc. using results of the recent studies developed for the industry (Ibis 2008 and Ibis 2009a). One su ch recent study stems from the USCAR-ACC composite structure programs that have be en involved in the detailed cost analysis of carbon-FRPMC body structures. Even deta iled cost analyses can have

limitations—in this case the limitation is that the program never developed a complete design or high production-volume-scale cost analysi s for a fully functional BIW structure. Cost data for other components—those for which the technology remained unchanged—were the same as those in the original mo del, since our objective in this analysis is to determine the relative cost-effectiveness of the plausible lightweight scenario to achieve the desired weight reduction go al and not the absolute total vehicle cost. Note that component technology costs in ASCM are based on OEM costs and represented in terms of functional relationships su ch as component mass and power, based on the detailed cost analyses available in th e literature.

Several recent USCAR-ACC composite structure progra ms have been used in order to extrapolate to a full BIW structure and panel syste m functionally equivalent to the carbon fiber scenario considered previously in ASCM. The A CC programs contributing to this analysis include the FP2-composite truck box, FP3-c arbon fiber structures, the Composite Underbody program, and a recent fiber, preforming, and molding technology tradeoff study (Ibis 2007, 2009b; Berger and Jaranson 2009 a nd Boeman and Johnson (2002)). The truck box study evaluated a high volume composi te design and process study employing P4 preforming and SRIM molding. Similarly , the carbon fiber structures program demonstrated a 60% mass savings over steel for a molded carbon fiber composite, although this was a large pillar type co mponent and not a full vehicle structure. The Underbody program examined a broad range of concepts, including random and fabric glass, carbon, and high modulus p olypropylene (HMPP) reinforcement through sheet molding compound (SMC) compression, l ong-fiber injection (LFI), and direct long-fiber thermoplastic (DLFT) molding proc esses. The most recent ACC tradeoff study compared glass, carbon, and natural fiber com posites produced through SMC, structural reaction injection molding (SRIM), and r esin transfer molding (RTM), and evaluated design based on equivalent strength and s tiffness. Mass savings on individual components relative to steel ranged from 37% to 70% depending on the tensile or modulus equivalency. As noted earlier, a mass savin gs of 55% has been assumed in our case of carbon-FRPMC body structure, i.e., BIW and panels. The production economics are based here on the recent studies using high pro duction rate P4 preforming and SRIM molding, achieving production rates of 15 parts per hour. The carbon material pricing is based on current volume pricing estimates of $30.80 /kg ($14/lb), rather than the optimistic $22/kg ($10/lb) used in some of the earl ier studies, and $4.24/kg for polyurethane systems.9

The entire body structure and carbon SMC panel syst ems were modeled using IBIS Technical Cost Models and the new regression analys es have been conducted to establish updated cost relationships sensitive to production volume, mass, material price, piece count, and part area. Figure 1 shows the estimated cost sensitivity to annual production volume of carbon-FRPMC body-in-white structures for a mid-size vehicle. Estimated costs are based on the baseline BIW and panel mass of 128 kg and 42 kg, respectively, representing a 49% reduction in mass compared to th e baseline steel body structures. As one would expect, carbon-FRPMC body structure is qu ite insensitive to annual production volume since it is a low-volume process: total part cost varies less than $20/part and is relatively constant at around $2,96 0/part beyond production volume of 50,000 parts/year.

The cost sensitivity to annual production volume fo r body-in-white structures of various materials is shown in Figure 2. The costs represent ed in Figure 2 include the assembly cost. Cost graphs shown here are based on the basel ine weight for a mid-size vehicle considered in the model and not the actual weight u sed in the analysis here. For example, baseline masses of body-in-white structure consider ed for steel, aluminum, and thermoset/glass composites (TS/glass composites) ar e 250 kg, 143 kg, and 202 kg, respectively. Current material pricing is as follow s: steel $0.77/kg; aluminum sheet $3.31/kg; aluminum casting $2.86/kg; vinyl ester co mpound $4.24/kg; glass fiber $1.50/kg; and carbon fiber $30.80/kg (reflecting a recent surge in demand for large commercial jet aircrafts). Based on these material prices and masses assumed, the carbonFRPMC structure is more expensive than all other li ghtweight material options considered here, except at annual production volume of 10,000 parts, when the aluminum unibody is more expensive than carbon-FRPMC. The cr ossover between these two materials is estimated to occur between production volumes of 10K-25K. Unlike the current estimate, most past studies indicate cost p arity of carbon-FRPMC with conventional baseline steel structure at a producti on volume in the range of 5,000-35,000 (Kang 1998 and Fuchs 2008). Their estimates of cost parity are mainly due to their assumption of lower carbon fiber prices of $11-$17. 50/kg, compared to this analysis’ assumption of $30.80/kg. Fuchs (2008) estimated cro ss-over point of 35,000 for the costeffectiveness of traditional steel and carbon compo sites represents 45% of car models and 10% of all cars produced in North America in 2005. The cost sensitivities of steel and aluminum structures are quite similar to each other in terms of the curve slope, but they are offset by the material price difference and som e increased processing costs. As also has been observed earlier, the cost sensitivity cur ves for composite body structures (i.e., for both glass-FRPMC and carbon-FRPMC) are relative ly flat compared to other materials. For our analysis, the threshold producti on volume of cost-effectiveness is 240K parts/year for baseline steel and 50K parts/ye ar for the lightweight vehicle.10 0 500 1000 1500 2000 2500 3000 3500 4000

0 50 100 150 200 250 300

Annual Production Volume (K)Carbon-FRPMC Body Structure Cost ($/part)

Structure

Assembly

Panels

Total

Figure 1. Carbon-FRPMC Body Structure Cost Sensitiv ity to

Annual Production Volume

0 500 1000 1500 2000 2500 3000

0 50 100 150 200 250 300

Annual Production Volume (K)Body-in-White Structure Cost ($/part)

Steel Unibody

Aluminum Unibody

TS/Glass Composite

CF Composite

Figure 2. Lightweight Material Body-In-White Cost S ensitivity to

Annual Production Volume11 0 100 200 300 400 500 600

0.5 1 1.5 2 2.5 3 3.5 4 4.5

Al Casting Price ($/kg)Part Cost ($) Brake System

Steering System

Cradle

Corner Suspension

Base Price $2.86/kg

Figure 3. Aluminum Chassis Component Cost Sensitivi ty to Material Price

Figure 3 shows the per-part cost sensitivity to alu minum casting price for four different aluminum chassis components considered under the ca rbon-FRPMC scenario based on part weight used in a mid-size vehicle. Note that t he part cost estimates for the base price of $2.86/kg for aluminum casting is also shown. The cost estimates for the aluminum cradle includes not only casting cost, but also mel ting, scrap recovery, machining, and corrosion protection. Cost estimates of aluminum br aking and steering systems were made by adding the estimated cost of replaced alumi num component (e.g., brake actuators and steering wheel column for braking and steering systems, respectively) to the unchanged original balance of system cost made of conventional steel. Cost data for replaced aluminum components are based on recent av ailable estimates (EEA 2007). Cost relationships consist of two components, i.e., mate rial and processing. As Figure 3 shows, the higher weight of the corner suspension causes i ts cost to be higher and more sensitive than the cradle is to aluminum ingot prices. The se nsitivity of steering and braking system costs to aluminum ingot pricing is not signi ficant since the aluminum components contributes less than 10% of total system weight in each case. Cost of cast magnesium

wheels are based on 15” wheels and reflects current material pricing and processing technology improvements and also includes tire cost s. It has been assumed to have 20% price premium compared to cast aluminum wheels (EEA 2007 and Long et al. 2005).

3.0 Results

Figure 4 shows the estimated cost savings resulting from the 40% body and chassis weight savings of the carbon-FRPMC scenario compare d to the baseline, by major vehicle systems, vehicle retail price, and life cyc le cost. Only three major vehicle systems12 -2500 -2000 -1500 -1000 -500 0 500 1000 1500

1Cost Savings ($/vehicle) Pow ertrain

Body

Chassis

Vehicle Retail Price

Operation

Life Cycle Cost

Figure 4. Estimated Cost Savings of 40% Body and Ch assis

Weight Reduction Scenario

are considered because the cost of other vehicle sy stems—interior, electrical, and final assembly—are assumed to be the same under all scena rios. There would be $1490/vehicle increase in retail price level and a $1100/vehicle increase in life cycle cost. The increase in vehicle retail price is mainly due to the body system cost increase of about $2200, the result of the higher cost of carbo n unibody structure. The cost savings due to the downsizing of the powertrain and chassis is not sufficient to lower the vehicle retail price. In addition, with the consideration o f quite a few operation cost categories (e.g., financing, insurance, and local fees) as fun ctions of vehicle retail price and the assumption of lower gasoline price of $1.90/gallon – a 40% weight reduction goal cannot be achieved even at the level of life cycle cost. I t is estimated that if the price of aluminum used in chassis components is reduced from the baseline price of $2.86/kg to $2.20/kg and carbon fiber price is reduced from the baseline price of $30.40/kg to DOE’s long-term target value of $6.60/kg, the cost-effect iveness at the life cycle cost level could be achieved, even at the assumed gasoline price of $1.90/gallon. As one would expect,

the cost-effectiveness of carbon-FRPMC vehicle woul d improve with higher fuel price as also shown here in Figure 5. It is estimated that i f the fuel price increased from a baseline price of $1.90/gallon to about $4.25/gallon, cost-e ffectiveness could be achieved at the level of vehicle life cycle cost without requiring any material price reductions. It is anticipated that a combination of material price de creases and a fuel price increase would be necessary to achieve the cost-effectiveness of c arbon-FRPMC vehicle at the level of vehicle retail price.13 40000 42000 44000 46000 48000 50000 52000

1 1.5 2 2.5 3 3.5 4 4.5 5

Fuel Price ($/gallon)Life Cycle Cost ($/Vehicle)

Baseline Steel

Carbon-FRPMC

Figure 5. Vehicle Life Cycle Cost Sensitivity to Fu el Price

4.0 Conclusions

Cost-effectiveness of ALM’s 2009 body and chassis w eight reduction goal of 40% in light-duty vehicles was assessed based on the use o f lightweight material options for various body and chassis components under a plausib le mid-size vehicle scenario. The weight reduction goal here is very similar to that of the Japanese government whose intention is to mass-produce a cost-effective, recy clable carbon fiber and use it to achieve a 40% reduction in cars by the middle of the next d ecade (Brooke 2009). The lightweight material substitution options considered here focus ed on carbon-FRPMC for body systems and aluminum for chassis components. Among potential lightweighting materials, carbon-FRPMC has the greatest weight sav ings potential. The analysis also considers the effect of primary weight savings of 4 0% on other vehicle components that can be resized while maintaining the same level of vehicle performance with the reduced vehicle weight. This weight savings are known as se condary weight savings. Due to consideration of secondary weight savings, total bo dy and chassis weight savings are estimated to be 45%, whereas the final vehicle weig ht savings of 28%. Cost-effectiveness of 40% body and chassis weight reduction goal is es timated in terms of both vehicle retail price and life cycle cost using the detailed 35+ co mponent level automotive system cost model developed by ORNL and Ibis Associates, Inc. C ost data of components considered14

for lightweight material substitution are collected from recent major studies, thereby reflecting the latest technology developments and m aterial prices.

Even with the consideration of powertrain resizing and secondary body and chassis mass savings, carbon-FRPMC lightweight material vehicle option is not cost-effective in meeting the ALM 40% body and chassis weight savings goal from the life cycle cost perspective if the recent low gasoline price trend continues. The higher cost results mainly from using the carbon-FRPMC body system whic h is $2200 more expensive than the baseline system. The higher cost is not offset during the vehicle operation stage. The higher vehicle retail price also affects some of th e operation cost categories such as financing, insurance, and local fees which are func tions of vehicle retail price. The vehicle retail price is estimated to be $1492 highe r than baseline. The life cycle cost is $1102 higher. From the life cycle cost perspective, either a change in material price or fuel price would be necessary to achieve the cost-e ffectiveness goal. Aluminum and carbon fiber prices need to be at $2.20/kg and $6.6 0/kg, respectively, whereas fuel price needs to be $4.25/gallon for the lightweight vehicl e to be cost effective. It is likely that a combination of material and fuel prices would be ne cessary to achieve the costeffectiveness at the level of vehicle retail price, which is the primary consideration of OEMs for determining the viability of any new vehic le technology. The extent of the necessary price changes would depend on the extent of secondary mass savings considered, with this analysis employing a conserva tive estimate of secondary mass savings. In contrast to this conservative estimate, General Motors 1992 Ultralite carbon body structure weigh 191 kg (compared to the 171 kg body structure in this analysis) demonstrated a super-lean 635 kg curb weight concep t car—considerably lower than our estimated curb weight of 1102 kg.

Findings in this analysis are consistent with the e arlier findings that carbon-FRPMC is too expensive for large scale application in light- duty vehicles today. Composite monocoque BIW designs considered in the past severa l studies indicate cost to be in the range of 41-73% higher than the steel unibody, depe nding on the type of tooling used (Mascarin et al. 1995). The technology is suited fo r mainly low annual production volume, and a reduction in carbon fiber price would help to a large extent in improving its viability. Vehicle platforming considerations w hich allow low annual production volumes would facilitate the competitiveness of car bon-FRPMC body structure (Fuchs et al. 2008). Lightweighting also improves the cost-ef fectiveness of advanced technology vehicles by lowering the expensive powertrain cost while maintaining the performance (Aluminum Association 2008, Brooke 2009, and Das 20 05). Consideration of powertrain resizing, secondary mass savings, and life cycle co st perspectives would therefore be important to maximize the fuel economy gains from a lightweight structure and eventual successful market penetration of lightweight vehicl es in the future. With a higher lightweighting goal, reduced material cost become m ore critical because it is such a large share of the total part costs particularly in low p roduction volume production manufacturing processes. Accordingly, a current foc us of DOE’s lightweight materials program is the development low cost carbon fibers f rom alternative cheap renewable resources and high-volume processing of composites.15 REFERENCES

Aluminum Association (2008). “Aluminum Vehicle Stru cture: Manufacturing and Lifecycle Cost Analysis: Hybrid Drive and Diesel Fu el Vehicles,” Research Report No. 2008-05, written by Ibis Associates, Inc. for t he Aluminum Association.

Berger, L. and Jaranson, J. (2009). “Automotive Com posites Consortium Focal Project 4,” FY 2007 Progress Report for Lightweighting Mate rials, Vehicle Technologies Program, U.S. Department of Energy, Washington, DC, Available at: http://www1.eere.energy.gov/vehiclesandfuels/resour ces/vt_lm_fy07.html, accessed

on 5/22.

Boeman, R. G. Johnson, N. L (2002). “Development of a Cost Competitive, Composite Intensive, Body- In-White,” SAE Paper No. 2002-01-1905, the Society of Automotive Engineers, Warrendale, PA.

Brooke, L. (2009). “A Featherweight Future,” Automo tive Engineering International, Vol. 117, No. 5, May, pp. 24-26

Das, S. (2004). “A Comparative Assessment of Altern ative Powertrians and Body-inWhite Materials for Advanced Technology Vehicles,” SAE Paper No. 2004-01-0573, the Society of Automotive Engineers, Warrendale, PA

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Das, S. (2005). “Lightweight Opportunities for Fuel Cell Vehicles,” SAE paper no. 2005- 01-0007, the Society of Automotive Engineers, Warre ndale, PA.

Das, S. (2008). “Cost-Effectiveness of a 25% Body a nd Chassis Weight-Reduction Goal in Light-Duty Vehicles,” draft report, Oak Ridge Na tional Laboratory, Oak Ridge, TN, Aug.

Energy and Environmental Analysis, Inc. (EEA) (2007 ). “Analysis of Light-Duty Vehicle Weight Reduction Potential,” draft final report sub mitted to the U.S. Department of Energy, Office of Policy, Arlington, VA, July.

Energy Information Administration (EIA) (2009). “An nual Energy Outlook 2009 with Projections to 2030, Updated Annual Energy Outlook 2009 Reference Case with ARRA, http://www.eia.doe.gov/oiaf/servicerpt/stimul us/excel/aeostimtab_12.xls

accessed on 5/28/09.

Fuchs, E. R. H. Field, F. R. Roth, R. and Kirchain, R. E. (2008). “Strategic Materials Selection in the Automobile Body: Economic Opportun ities for Polymer Composite Design,” Composites Science and Technology, Vol. 68 , pp. 1989-2002.

Ibis Associates, Inc. (Ibis) (2007). “Technical Co st Model Development for a Structural Composite Underbody: Supporting USCAR-ACC Composite Structures Program,” Waltham, MA.16

Ibis Associates, Inc. (Ibis) (2008). “Data Documen t: ORNL Automotive System Cost Model,” Waltham, MA, July 1.

Ibis Associates, Inc. (Ibis) (2009a). “Data Docume nt: ORNL Automotive System Cost Model,” Waltham, MA, April 9.

Ibis Associates, Inc. (Ibis) (2009b). “Technical C ost Analysis & Model Development: Fiber and Process Preforming Alternatives: Supporti ng USCAR-ACC Composite Structures Program,” Waltham, MA.

Iobst, S. Berger, L. Fernholz, K. Dahl, J. and Smit h G. (2007). “Fabrication of the Automotive Composites Consortium Carbon Fiber B-Pil lar,”International SAMPE Symposium and Exhibition (Proceedings), v 52, SAMPE ’07: M and P – From Coast to Coast and Around the World, Conference Proceedin gs, 2007, 11p.

Long, S. Xu, S. and Cao, H. (2005). “Technical Econ omic Considerations for Production and Application of Mg Castings in China,” Materials Science Forum, Vols. 488-489, pp. 909-914, June.

Malen, D. E. and Reddy, K. (2007). “Preliminary Veh icle Mass Estimation Using Empirical Subsystem Influence Coefficients,” report prepared for the FGPC Mass Compounding Project Team, Auto/Steel Partnership, S outhfield, MI, May 9.

Marsh, G. (2006). “Composites Conquer with Carbon S upercars,” Reinforced Plastics, Jan., pp. 20-24.

Mascarin, A. E., Dieffenbach, J. R. Brylawski, M. M . Cramer, D. R. and A. B. Lovins (1995). “ Costing the Ultralight in Volume Producti on: Can Advanced Composite Bodies-In-White Be Affordable?,” paper presented at the 1995 International Body Engineering Conference & Exposition, held on Oct. i n Detroit, MI.

Plotkin, S. et al. (2001). “Hybrid Vehicle Technolo gy Assessment: Methodology, Analytical Issues, and Interim Results,” Argonne Na tional Laboratory Report ANL/ESD/02-2, Argonne, IL.

Rousseau, A. Sharer, P. and Das, S. (2005). “Trade- off between Fuel Economy and Cost for Advanced Vehicle Configurations,” presented and published at EVS21conference, held in Monaco, Apr. 2-5.

Ultra light Steel Autobody – Advanced Vehicle Conce pts (ULSAB-AVC) (1999). “Description of ULSAB-AVC Benchmarking and Target S etting,” Southfield, MI.

Nov. 18.17 

### Appendix A ASCM Vehicle Component Definition

ASCM UPG ASCM Description

Group Name

Powertrain Engine 30A Base Engine In this model, 'engine' refers to c onventional heat engines. In addition to basic powerplant and auxil iary systems and components, engine cooling systems, lubrication, fluid containers and pumps are also in cluded. 30B Other Engine

Components

Fuel Cell n/a Fuel Cell Power System

Generator n/a The APU or power converter for paral lel and series hybrids. Motor n/a The electric motor, including power cabl es.

Controller/

Inverter n/a The power controller/phase inverter system

Energy Storage 36K01 High Voltage Battery The primary electrical energy storage device or pac kage.

Maybe a single battery or module of linked cells. Fuel System 36F Fuel Tank and
Lines Fuel tank, gauge, tank shield, access door, mountin g

straps, fuel pump.

37B Fuel

Transmission 36E G Transmission In this model the transmission r efers to the gearbox only. Note that in some literature, "transmission" refers to the clutch, gearbox, driveshaft, and differential. The se are each treated as separate components/subsystems in t his
model.

36C Clutch and

Controls Supplied as a single assembly, a releasable couplin g that

transmits torque from the engine to gearbox.

Driveshaft/
Axle 31 Final Drive A single assembly that couples wit h the gearbox and
differential

31 Final Drive An assembly of the axle shaft, housi ng, boots, and couplings to the wheels

Differential 31 Final Drive Transmits energy from driveshaft to axles and allows for differential speed of each wheel.

P/T Thermal Cooling module (radiator, fan assembly etc)

Exhaust System 36E

36O Exhaust System

Catalytic
Converter All exhaust equipment after the manifold; pipe: cat alytic

converter, muffler.

Powertrain
Electrical 30C Engine Electrical Engine control wiring, sensor s and processors. The controller for electric motors for HEVs may be cons idered as part of the electric motor, or could be included here, if desired. Low voltage used for accessory power is a lso
included here.

Emission
Control
Electronics 30C10 Engine Emission
Controls The sensors, processors, and engine feedback

equipment that maintain emissions within specified parameters.
Oil and
Grease 37B Oil and Grease Engine oil, transmission oil, mi scellaneous lubricants18 ASCM UPG ASCM Description

Group Name

Body BIW 11A-11B Body in White and
closures The Body-In-White is the primary vehicle structure,

usually a single-body assembly, consisting of engin e compartment, passenger cabin, and storage. Closure panels (including hinge mechanism) and hang-on pane ls (such as fenders) are included, even if non-structu ral. In this model, doors are included as well.

Front/Rear Bumper 36G Fenders

Glass 18 Glass Front and rear windshields, door win dow glazing

Paint 22 Paint and Coating Includes the cost and mass of the total painting operation; e-coat, priming, base coats, color coats, clear coa ts. 37A, C, D Paint

Exterior

Trim 14, 20 Molding and
Ornaments Bumper cover, air deflectors, ground effects, side trim,

mirror assemblies, nameplates

Body
Hardware Door window mechanism, wipe/wash, defog/deice, do or latch mechanism

Body
Sealers &

Deadeners Self-explanatory

Chassis Cradle 32 Frame A front sub frame that bolts to the BIW an d supports the mounting of the engine

Corner Suspension 33 Suspension Upper and lower control arms, ball jo ints, spring, shock absorber, steering knuckle, stabilizer shaft Braking System 35 35D Brakes Hub, disc, bearings, splash shield, a nd calipers.

Wheels and
Tires 36A 36C Wheels, Tires, and
Tools Self explanatory. Tools determinant by type of tir es

featured. Steering System 34 Steering A complex system from the steering whee l, column, joints, linkages, bushes, housings and potentially hydraulic or electric assist equipment.

Interior Instrument

Panel 21 Trim and
Insulation The instrument panel module consists of an underlyi ng

panel structure, knee bolsters and brackets, the instrument cluster, exterior surface, wiring, conso le storage, glove box panels, glove box assembly and exterior, and a top cover.

Trim and
Insulation 15,17,21 Headliner Headliner is actually the overhe ad system containing acoustical sound absorption, assist handles, coat h ooks, modular headliner assemblies, overhead console assemblies, small item overhead storage, pillar tri m, sun visors and retainer. Center Console Emergency brake cover, switch panel s, ash trays, arm rest, cup holders, sometimes grouped with seating.

Package Tray A molded or formed panel behind the r ear seat, sometimes contains accessory brake light.

Carpeting/Flooring Acoustical sound absorption; padding and carpet,
insulation and accessory mats sometimes flooring may be sold as part of a combined acoustic package, also involving other sound abatement components, such as
wheel well liners and under hood insulation

Door
Modules 19 Convenience
Items A door panel system containing door insulation, doo r trim

assemblies/panels, map pocket trim, cup holders, as h trays, seatbelt retractor covers, speaker grills, a rmrests, switch panels and handles

Seatbelt &
Restraints 16 Seats The seating system contains seat tracks, s eat frames, foam, trim, map pockets, restraint anchors, head re straint,19 ASCM UPG ASCM Description

Group Name

and armrests.

81 Safety Equipment Seat belts, tensioners, clips, air bags and sensors
assemblies

HVAC 80A, B Air Conditioning System Condenser, heater, ducting, and controls, compresso r

and A/C hardware.

80H, J Heating System

80K, M, C Other Climate

Control

Electrical Interior

Electrical 12F-13, 79 Electrical Components Wiring and controls for interior lighting, instrume ntation,

and power accessories, entertainment system.

85 Accessories

Equipment

Chassis

Electrical 36K Chassis Electrical ABS electrical system (wirin g, sensors, processors),
traction control

Exterior
Electrical 14,20 Molding and
Ornaments Head lamps, fog lamps, turn signals, side markers, tail

light assemblies

Final Assembly Interior

Chassis

Powertrain

Electronics

Other Systems Final assembly of vehicle components is represented at the level of five major vehicle subsystems under wh ich components are grouped