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7 Non-Powertrain Technologies
Pages 201-237

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From page 201...
... A 2013 National Research Council committee estimated that under average driving conditions, a 10% reduction in drag resistance would reduce fuel consumption by about 2%. In that study's scenarios, reduction in newvehicle-fleet aerodynamic drag resistance for the midrange case is estimated to average about 21% (4% reduction in fuel consumption)
From page 202...
... Additional passive aerodynamic technologies can be employed during the midcycle refresh process. Vehicle components that can be added or modified to decrease aerodynamic drag include the exterior mirrors, underbody panels, front air dams, front and rear fascia, rear deck lips, and rear valances.
From page 203...
... This reduces aerodynamic drag, thereby leading to improved fuel economy. AGS offers significant weight reduction up to 20%, owing to lower weight materials, and improvement in aerodynamic performance up to 3.0% compared to a nonAGS vehicle.
From page 204...
... The most aerodynamic drag reduction is achieved when a vehicle is lower to the ground; thus, active ride height systems automatically decrease vehicle height during smooth driving conditions (e.g., highway) to achieve the highest possible fuel efficiency (YourMechanic, 2015)
From page 205...
... . TABLE 7.4  DMC for Aerodynamic Drag Reductions Passenger Cars and SUVs DMC Pickup Trucks DMC AERO Level (2018$, MY 2017)
From page 206...
... . Some active aerodynamic drag reduction technologies, such as active ride height and active air dams, are available for implementation but have not been widely offered by manufacturers.
From page 207...
... .1 (See Chapter 11 for further discussion of consumer choice.) The committee considers primary and secondary mass reductions in estimating the cost and fuel economy effectiveness of material substitution and design optimization for manufacturers' compliance options.
From page 208...
... 208 ASSESSMENT OF TECHNOLOGIES FOR IMPROVING LIGHT-DUTY VEHICLE FUEL ECONOMY -- 2025–2035 TABLE 7.6  Average Material Use in the North American Light-Duty Fleet 2008–2018, Reported in Pounds per Vehicle and as Percent of Total Vehicle Weight 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Average weight (pounds/vehicle) 3965 3860 3865 3914 3806 3812 3834 3889 3929 3960 3979 Regular steel 1596 1462 1422 1405 1335 1322 1308 1293 1295 1222 1215 High- and medium-strength steel 513 510 541 594 604 612 632 681 720 765 772 Stainless steel 74 67 70 71 66 72 71 73 72 72 71 Other steels 32 30 31 31 29 31 31 31 31 31 30 Iron castings 248 201 236 255 263 264 271 260 242 244 249 Aluminum 310 319 332 337 342 348 361 387 404 415 427 Magnesium 11 11 11 11 10 10 9 9 9 10 10 Copper and brass 69 70 72 71 70 69 67 65 67 69 69 Lead 43 41 40 38 35 34 35 35 35 37 34 Zinc castings 9 9 9 9 8 8 8 8 8 9 9 Powder metal 42 40 40 41 43 44 45 44 43 44 44 Other metals 5 5 5 5 5 5 4 5 5 5 5 Plastics/polymer composites 334 368 343 336 319 317 317 324 325 348 351 Rubber 202 246 228 223 205 197 194 196 196 204 205 Coatings 31 35 35 32 27 27 28 28 28 30 28 Textiles 47 57 54 49 48 49 48 44 44 46 46 Fluids and lubricants 211 214 215 217 215 218 220 221 222 222 223 Glass 97 87 90 96 93 94 94 93 92 95 97 Other 89 88 90 91 89 90 91 93 91 92 95 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 As a percent of total weight 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Regular steel 40.2 37.9 36.8 35.9 35.1 34.7 34.1 33.2 33.0 30.9 30.5 High- and medium-strength steel 12.9 13.2 14.0 15.2 15.9 16.1 16.5 17.5 18.3 19.3 19.4 Stainless steel 1.9 1.7 1.8 1.8 1.7 1.9 1.9 1.9 1.8 1.8 1.8 Other steels 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Iron castings 6.3 5.2 6.1 6.5 6.9 6.9 7.1 6.7 6.1 6.2 6.2 Aluminum 7.8 8.3 8.6 8.6 9.0 9.1 9.4 10.0 10.3 10.5 10.7 Magnesium 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.3 Copper and brass 1.8 1.8 1.9 1.8 1.8 1.8 1.7 1.7 1.7 1.7 1.7 Lead 1.1 1.1 1.0 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Zinc castings 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Powder metal 1.1 1.0 1.0 1.0 1.1 1.2 1.2 1.1 1.1 1.1 1.1 Other metals 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Plastics/polymer composites 8.4 9.5 8.9 8.6 8.4 8.3 8.3 8.3 8.3 8.8 8.8 NOTE: Polypropylene is also used in the thermoplastics polyolefin elastomers (TPO)
From page 209...
... Between 2020 and 2035, growth is seen in the use of generation-3 steel, magnesium, plastics, and composites. Reductions are seen in the use of mild steel, high-strength steel, hydrogen fluoride (HF)
From page 210...
... There would still be mass and fuel economy improvement from implementation of mass reduction technologies
From page 211...
... Different grades of steel span a wide range of ultimate tensile strengths, 20% Pickup Trucks Footprint Change from MY 2016 to MY 2020 15% Mass 10% 5% 0% -5% -10% -15% FIGURE 7.5  Mass reduction and change in footprint for the top-selling pickup truck models in their most recent redesign. When sales-weighted, the top-selling pickup trucks average 4% mass reduction and a 6% increase in footprint.
From page 212...
... . SOURCE: Committee generated using model-by-model 2010 and 2016 MY data released as part of NHTSA and U.S.
From page 213...
... SOURCE: Committee generated using model-by-model 2010 and 2016 MY data released as part of NHTSA and EPA rulemakings.
From page 214...
... was approximately 50% of vehicles in 2019, up from about 20% in 1975. SOURCE: Committee generated using data from EPA (2020)
From page 215...
... and chassis. These modifications result in a 700 lb curb weight reduction, which improves fuel economy by 19%.
From page 216...
... 3 2.5-3 $/lb-saved 2-3 2-3 $/lb-saved $/lb-saved 2-2.5 Weight1 (lb) 10 1.5-2.5 $/lb-saved 2 $/lb-saved 48% 45% 5 47% 1 7xxx 2nd Gen 7xxx 1st Gen 46% Steel B Pillar Rocker A Pillar Roof Rail Door Beam Reinforcement FIGURE 7.11  Components, weight-saved, and value in use for the primary mass reduction of several vehicle components in transitioning from steel to first- and second-generation 7xxx aluminum alloys.
From page 217...
... . Carbon fiber was first used primarily in sports cars and at low production volume; however, the introduction of BMW's i3 in 2013 moved these composite materials into mass production, and opportunities for carbon fiber and other polymer composites continue to grow.
From page 218...
... Although the material cost of automotive grade carbon fiber has decreased significantly in recent years (Table 7.8) , both the raw material and manufacturing costs of composites, in $/lb of material, are expected to be significantly higher than those for metals in 2025–2035.
From page 219...
... light-duty vehicles in 2020–2040 are shown in Figure 7.2 above. The costs per lb of mass reduction for unibody cars/SUVs and pickup trucks with various possible material substitution types are depicted in Figures 7.14 and 7.15, respectively.2 These plots of cost per percent mass reduction consider lightweighting from materials substitution only, not from modification or removal of vehicle components as would be done in a full design optimization.
From page 220...
... for different levels of mass reduction from material substitution in pickup trucks. NOTE: Black diamonds indicate a representative vehicle in each scenario, and blue boxes denote uncertainty in percent mass reduction and cost within that scenario.
From page 221...
... . TABLE 7.10  Projected Costs, Mass Reduction, and Material Trends for Potential Scenarios in 2025–2035 Vehicle Class Scenario Costa Mass Reductionb Expected Material Trend Cars and Unibody SUVs Baseline N/A N/A Body: HSS, AHSS, UHSS Closures: HSS, low Al One $0.22–$0.67 1.0%–1.5% Body: HSS, AHSS, UHSS Closures: HSS, Al Two $1.78–$2.67 12%–14%c Body: Al, AHSS, UHSS Closures: Al, comp, Mg Three $0.67–$1.56 4%–6% Body: AHSS, UHSS, low Al Closures: Al Pickup Trucks Baseline N/A N/A Body: AHSS, UHSS Frame: AHSS, UHSS Closures: HSS, Al One $0.22–$0.67 2%–3% Body: AHSS, UHSS, Al Frame: AHSS, UHSS Closures: Al Two $0.6 –$1.11 8%–10%c Body: Al Frame: AHSS, UHSS Closures: Al Two (alternative)
From page 222...
... Figure 7.17 shows details of the process for vehicle and component designs that meet specifications while minimizing cost, weight, or other parameters. The automotive industry must continue to improve fuel economy and/or EV range for a customer who expects these improvements but is unwilling to pay for them.
From page 223...
... 7.2.6 Findings and Recommendation for Mass Reduction FINDING 7.4: Lightweighting represents the greatest opportunity for fuel economy improvement in road load and accessory reduction. There have been many breakthroughs in high-strength steel, aluminum alloys, and composites, as well as manufacturing methodologies, to allow further implementation.
From page 224...
... . The fuel economy benefit of reducing rolling resistance depends to a great extent on the fraction of energy input to the vehicle that is used to provide power to its wheels to overcome inertia, aerodynamic drag, and rolling resistance.
From page 225...
... NON-POWERTRAIN TECHNOLOGIES 225 FIGURE 7.18  Diagram of energy requirements for combined city/highway driving for gasoline vehicles, showing the power to the wheels after engine losses, parasitic losses, drivetrain losses, auxiliary electric losses, and idle losses.
From page 226...
... . FIGURE 7.21  Tire rolling resistance values (RRC, in kg/1,000 kg)
From page 227...
... a 20% Crr reduction (ROLL20) , giving a 3.9% reduction in fuel consumption over the base tire (EPA, 2016)
From page 228...
... Department of Energy has sponsored tire research with the objective of improving vehicle fuel economy by 3% and reducing tire weight by 20% through a combination of six technological advances (Donley, 2014)
From page 229...
... FINDING 7.9: Noninflatable tires are being developed, specifically for urban, shared vehicles, but the impact to fuel economy is not likely to improve upon adoption of pneumatic tires. 7.4 ACCESSORIES AND OTHER OFF-CYCLE TECHNOLOGIES Additional improvements to accessories and related technologies are off-cycle technologies, meaning that their fuel economy benefits are not captured on the Federal Test Procedure (FTP)
From page 230...
... Although reductions in A/C leakage and alternative low-GWP refrigerants do not affect fuel economy, reducing coolant leaks through improved hoses, connectors, and seals and replacing current coolants with lower GWP refrigerants do reduce overall GHG impacts from light-duty vehicle operations. 7.4.3 Tire Off-Cycle Technologies Tire rolling resistance is sensitive to inflation pressure.
From page 231...
... Other factors include vehicle crashworthiness and vehicle-to-vehicle mass disparity and structural and geometric compatibility. While any implications of fuel economy regulations for vehicle safety have been small compared to the primary determinants of vehicle safety, understanding and addressing the potential unintended consequences is important.
From page 232...
... To improve fuel economy, automakers are expected to redesign about 40% of vehicles in the MY 2020 baseline fleet by MY 2025 using both design optimization and materials substitution to reduce vehicle mass, as noted earlier in this chapter. During 2025–2035, these lightweighting efforts will likely occur concurrently with increased adoption of electric powertrains and comfort and safety features associated with driver assist and CAVs, both of which increase vehicle mass.
From page 233...
... RECOMMENDATION 7.4: The National Highway Traffic Safety Administration should continue to study how crashes change in an advanced driver assist systems-enabled fleet, and if changes in crash propensity or severity affect the total societal safety risk when more vehicles also incorporate improved fuel economy technologies, such as new materials or advanced powertrains. RECOMMENDATION 7.5: The National Highway Traffic Safety Administration should study potential changes in mass disparity in 2025–2035, particularly disparities that may arise from a shift from sedans to crossover vehicle/sport utility vehicle/pickup trucks, mass increases in one vehicle class but not another, lightweighting to improve fuel efficiency and performance, and increases in mass from electrified powertrains and other safety and comfort features.
From page 234...
... Technology Effectiveness Technology 2025 2030 2035 (% Fuel Consumption Reduction) a Mass reduction -- unibodyb 1%–1.5% 0.45–0.67 0.22–0.67 0.05–0.22 0.6–1.05 4%–6% 0.67–1.78 0.67–1.56 0.58–0.89 2.4–4.2 12%– 14%c 1.78–2.67 1.78–2.67 1.34–1.78 7.2–9.8 Mass reduction -- truckb 2%–3% 0.45–0.67 0.22–0.67 0.05–0.45 0.8–1.5 8%–10%c 0.67–1.27 0.89–1.34 0.45–0.89 3.2–5.0 10%–12%c 4.01–4.90 3.34–4.45 2.67–3.56 4.0–6.0 Aerodynamic drag reductiond 5% 35.50 30.28 27.37 1.3 10% 68.49 61.91 55.97 2.3 15% 96.78 87.48 79.08 3.5 20% 171.23 154.78 139.91 4.8 Tire rolling resistance reductione 10% 4.24 4.00 3.89 2 20% 27.19 24.80 24.32 4 aFuel consumption reduction is relative to a baseline vehicle, and not incremental to previous technology.
From page 235...
... 2012. Joint Technical Support Document: Final Rulemaking for the 2017–2025 Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards.
From page 236...
... "Methodology for Evaluating Fleet Protection of New Vehicle Designs: Application to Lightweight Vehicle Designs." DOT HS 812 051A. National Highway Traffic Safety Administration.
From page 237...
... 2020. "Simulation-Driven Lightweight Design for Automotive Structures." Presented at the Design Optimization and Lightweighting Webinar to the Committee on Assessment of Technologies for Improving Fuel Economy of Light-Duty Vehicles -- Phase 3.


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