Summary briefing on four major new mass-reduction assessment for light-duty vehicles

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Morgan Boyd
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1 Summary briefing on four major new mass-reduction assessment for light-duty vehicles In , in the development of US passenger vehicle standards for model years , there were many questions about which advanced vehicle technologies would be most critical to cost- effectively increase vehicle efficiency. Table 1 shows the technologies that are in various stages of deployment and development globally, and their potential for reducing vehicle fuel consumption. In particular, how much the vehicles mass might be reduced with lightweighting technology compared to the use of other technologies was a critical question. Many automakers were expending great effort to reduce vehicle mass, whereas other manufacturers were putting far more resources into advancements in engines, hybrid drivetrain, and electric- drive vehicles. The high uncertainty on this question, led the government agencies of the U.S. to conduct novel research in this area of mass reduction. Within the table, mass reduction is shown to bring forth smaller improvements of 1-5% fuel consumption reduction from material substitution (e.g., piece substitution of aluminum for steel) and larger 5-10% improvement from full vehicle redesign of the entire vehicle. Generally a 10% mass reduction results in a 5-7% fuel consumption reduction (depending on the drive cycle), if a powertrain is downsized for constant acceleration performance. Table 1. Summary of technologies and fuel consumption reduction potential Area Technology for CO 2 reduction Technology share in US, MY2010 Potential fuel consumption reduction Low friction lubrication % Engine friction reduction - 2-4% Variable valve timing/lift 86% 4-6% Cylinder deactivation 7% 5-6% Powertrain Engine Turbocharging 3% 2-5% Turbo, gasoline direct injection 9% 8-15% Cooled EGR, turbo, GDI % Vehicle Transmission Compression ignition diesel 0.50% 15-25% Digital valve actuation % Early torque converter lock- up % Optimized shifting - 2-6% 6+ speed 40% 2-8% Continuously variable 10% 8-11% Dual- clutch, automated manual % Aerodynamics - 2-5% Tire rolling resistance - 2-4% Accessories (steering, air cond., alternator) - 1-4% Mass-reduction Advanced material component - 1-5% Integrated vehicle design % Stop- start mild hybrid <1% 6-8% Hybrid systems Full hybrid electric system 3% 30-35% Plug- in electric % Sources: US EPA, NHTSA, CARB assessments for fuel economy and CO 2 standards 1

2 There four major new assessments all sought to better understand technical feasibility, the manufacturing costs, and crashworthiness of significantly mass- reduced vehicle designs that were capable of the same utility of conventional vehicles (e.g., same or better acceleration performance, interior space, etc). Each study utilized independent automotive engineering firms whose primary business is to provide engineering services to the major automobile manufacturing companies. Each study was a major undertaking utilizing 5-10 engineering staff, working full- time for over a year, and costing approximately $1-2 million. The four major studies of note are listed in Table 2. Each of these engineering reports is hundreds of pages long with technical specifications and details about the vehicle material choices and the design steps. Each of these four studies surpassed all previous vehicle mass reduction work in terms of technical rigor, state- of- the- art Computer Aided Engineering (CAE) and finite element analysis (FEA) simulation techniques, appropriateness for vehicles in the timeframe, and crashworthiness and safety validation techniques. In addition each on offered unprecedented transparency into detailed assumptions. Finally, three of them were formally and thoroughly peer- reviewed by auto industry experts. Table 2. Summary of four major mass-reduction technology assessments Technical contractor Base vehicle, mass reduction, link FEV, 2012 EDAG, 2012 Lotus, 2012 EDAG, Toyota Venza Up to 18% mass reduction (at net $148 incremental vehicle cost saving) For US Environmental Protection Agency 2011 Honda Accord Up to 22% mass reduction (at incremental $319 per vehicle cost increase) For National Highway Traffic Safety Administration 2009 Toyota Venza Up to 32% mass reduction (at up to $419 per vehicle cost savings) For California Air Resources Board Small car (Approx Volkswagen Polo) Focuses in particular on mass reduction for electric vehicle design Up to 15% mass reduction with no net vehicle cost increase For WorldAutoSteel The basic steps of each of the four engineering projects are to start from a chosen or representative vehicle design (e.g., the Honda Accord sedan or the Toyota Venza crossover utility vehicle), conduct a teardown assessment of all the individual parts of the vehicle, identify class- leading and available mass- reduction technologies, re- design the vehicle with mass- reduced technologies adopted throughout the vehicle subsystems, conduct mass optimization through computer- aided engineering techniques, crash simulation for global safety and crashworthiness tests, and iterations back on vehicle design as needed. More than the other major technologies, mass reduction involves a full redesign of the vehicles (whereas, for example, the addition of many new engine technologies does not require a full vehicle redesign). Because the whole- vehicle redesign is necessary, the new 2

requirements to ensure they could perform well in relevant front, side, rear, roof crashes. The abovementioned low- mass vehicle designs by Lotus, EDAG, and FEV were tested specifically to meet U.S.

3 vehicle model must be tested for their crashworthiness in terms of safety. For example, the low- mass body structures must be evaluated for their performance for United States Federal Motor Vehicle Safety Standard (FMVSS) and Insurance Institute for Highway Safety (IIHS) requirements to ensure they could perform well in relevant front, side, rear, roof crashes. The abovementioned low- mass vehicle designs by Lotus, EDAG, and FEV were tested specifically to meet U.S. federal impact requirements including side impacts and door beam intrusion (FMVSS 214), seatbelt loading (FMVSS 210), child tether loadings (FMVSS 213), front and rear end chassis frame load buckling stability, full frontal crash stiffness and body compatibility (FMVSS 208), roof crush (FMVSS 216), rear impact (FMVSS 301), and frame performance under low- speed bumper impact loads ( bumper A- surface offsets, ) as defined by the IIHS. Figure 1 illustrates the image of impacts, for the frontal crash of the 32% mass reduced Lotus design against a frontal barrier. In this test, as well as the others, the low- mass vehicle models met their requirements and were validated for required safety regulations as specified. Bottom view Side view Figure 1. Illustration of 32% mass-reduced Lotus design after frontal crash at 35 miles per hour against fixed barrier (Lotus Engineering, 2012) The technologies available for mass reduction are wide- ranging for new materials, new designs, and advanced optimization techniques. Material substitution involves, generally, moving from heavier steels to stronger high- strength steel alloys, or to aluminum. In addition, advanced plastics and composites offer major mass reductions in interiors and increasing in structural components. Advanced magnesium and carbon fiber also may offer greater improvements in the longer term. Illustrative listing of technology innovations in each subsystem of the vehicle are shown for the EPA FEV study in Table 3. Overall, a 18% mass reduction was found at a $148 net cost savings per manufactured 3

4 vehicle was found in the US EPA- sponsored study. This design utilizes a far greater fraction of higher strength steel alloys, as well as some aluminum. Overall, the higher costs of advanced lighter and higher strength metal alloys in the vehicle body are offset by the reduced costs and materials in other systems (engine, suspension, brakes) that can be scaled down for constant vehicle utility and performance. Table 3. Example of mass-reduction by vehicle subsystems for 18% mass reduction Vehicle subsystem Baseline mass (kg) Mass reduction (kg) Percent mass reduction Incremental technology cost ($) Engine % (33.7) Transmission % Body- in- white, closures % Interior % (123.0) Exterior % (7.5) Glazing, body % 15.3 Suspension % (144.7) Driveline % 0.2 Brake % (169.6) Frame, mounting % 3.3 Exhaust % (2.5) Fuel % (3.9) Steering % (11.1) Climate control % (9.3) Info, gage, warning % (0.2) Entertainment % (2.4) Lighting % 0.8 Electrical % (1.4) Fluid, miscellaneous % 0.0 Total % (148.1) Source: US EPA, Figure 2 shows the results for the full vehicle redesign studies by EDAG, FEV, and Lotus. The full- vehicle results suggest that substantial amounts of mass reduction are available at modest costs. The four major studies all demonstrated mass- reduction of 15-32% mass reduction across different vehicle models (i.e., from small car to mid- size sport utility vehicle) using different mass- reduction techniques (e.g., more use of steel versus more aluminum). Significantly, each study suggested that the costs of all these mass reduction technologies would be quite low. The highest cost finding was for $319 in incremental cost per vehicle for NHTSA s 22% mass reduction. The other three studies suggested that mass- reduction would occur with a net cost saving once the entire vehicle was considered holistically. A major finding is that these innovations become possible due to comprehensive inclusion of all vehicle systems jointly within more advanced computer- aided engineering techniques that have matured. These major cost reductions are only possible if the technologies are scaled up to high economies of scale of at least 100,000 vehicles per year. 4

5 !"#$%&%"'()*#+,'*+-*&(,,* $%./#'0+"*1234%50#)%6* "###$ %&#$ &##$ '&#$ #$ #($!'&#$ &($ "#($ "&($ '#($ '&($ )#($ )&($!&##$!%&#$!"###$ 7%50#)%*&(,,*$%./#'0+"8*9%$#%"'*+-*#/$:*;%0<5'* *+,-$./012$ Figure 2. Four major studies findings on potential for mass reduction and associated incremental vehicle costs 34+5$6/789+10/:0;;8$ <=>:+$34+5$ References: Lotus Engineering, Evaluating the Structure and Crashworthiness of a 2020 Model- Year, Mass- Reduced Crossover Vehicle Using FEA Modeling. Prepared for California Air Resources Board. Singh, Harry, Mass Reduction for Light-Duty Vehicles for Model Years National Highway Traffic Safety Administration. Report No. DOT HS ftp://ftp.nhtsa.dot.gov/cafe/ _final/ pdf U.S. Environmental Protection Agency, Light- Duty Vehicle Mass Reduction and Cost Analysis Midsize Crossover Utility Vehicle. Prepared by FEV. EPA R WorldAutoSteel, Future Steel Vehicle: Phase 2 Report. EDAG_Phase2_Engineering_Report.pdf 5

Lightweighting as a Measure to Reduce GHG Emissions

Lightweighting as a Measure to Reduce GHG Emissions ICCT International Workshop on greenhouse gas reduction potential and costs of light-duty vehicle technologies John German April 27, 2012 Brussels Outline