Aluminum and Fuel Economy Michael Bull, director of Automotive Technology Novelis Inc.
Ricardo Study Objectives • Quantify impact of vehicle weight reduction (5%, 10%, 20%) – Fuel economy – Performance • Quantify impact of weight reduction with engine downsizing – Maintain vehicle performance level • Evaluate weight reduction with different engine types – Gasoline – Diesel
Vehicle Selection • Five vehicle classes – Representative range of vehicle weights and engines – Passenger and light‐duty truck • Vehicle Class / Comparator Vehicle Small Car/Mini Cooper Mid-Size Car/Ford Fusion Small SUV/Saturn Vue Large SUV/Ford Explorer Truck/Toyota Tundra
Simulation Model – General Description • Physics‐based model for each vehicle configuration – Vehicle – Engine – Driving schedule • Simulates accelerator and/or braking to achieve driving schedule • Runs on a millisecond‐by‐millisecond basis • Simulates speed and fuel usage
Simulation Model – Vehicle Parameters • Vehicle • Final drive – Configuration (FWD, RWD or – Gear ratio AWD) – Efficiency – Weight (front / rear – Rotational inertia distribution) – Spin losses – Wheelbase – Spin losses ‐ 4‐WD operating in 2 WD – Frontal area – Coefficient of drag (Cd) – Center of gravity • Wheels / Tires – Rolling radius (tire size) – Rolling resistance coefficients – Rotational inertia – Maximum friction coefficient – Slip at peak tire force
Simulation Model – Engine/Transmission Parameters • Engine – Torque curves ‐ full load, closed throttle motoring – Fuel consumption ‐ entire speed and load range – Idle and redline speeds – Rotational inertia – Turbo‐lag model (turbocharged diesel engines) – Parasitic loads: • Alternator • Power steering • Cooling fan – electric, belt driven • Transmission – Torque converter curves – Gear ratios – Shift and lock‐up maps – Efficiency and pumping losses ‐ each gear – Rotational inertias
Vehicle Simulations • Vehicle fuel economy (MPG) – EPA FTP75 (city) – EPA HWFET (highway) – ECE (European) – Steady State 30, 45, 60 and 75 MPH • Vehicle performance (sec.) – 0 – 10 MPH – 0 – 60 MPH – 30 – 50 MPH – 50 – 70 MPH • Each vehicle: – Baseline – Base engine: weight reduced by 5%, 10% and 20% – Reduced weight and engine downsized to match the baseline vehicle performance
Model Validation • Simulation results compared to published data for the comparator vehicle – No attempt to “calibrate” models Simulation Simulated Fuel Economy vs. Comparator (% diff) Roadload Force VEHICLE Maximum Variation vs. EPA City EPA Highway Combined Comparator Small Car 0.2% 2.5% -0.6% 1.3% Mid-Size Car 2.5% 0.2% -1.4% -0.4% Small SUV 1.1% 1.8% -4.4% -0.4% Large SUV 1.7% 5.9% -1.1% 3.5% Truck -1.3% 2.2% -1.9% 0.7%
Mid‐Size Car – 3.0L‐4V Gas Engine With Variable Intake Cam Timing • Vehicle Performance Simulation Results at Full Engine Load (WOT)
Fuel Economy Simulation Results: Mid‐Size Car 3.0L‐4V Gas Engine with Variable Intake Cam Timing
Ricardo Study Findings • Excellent correlation between simulation and actual vehicle • Fuel economy improvement with 10% weight reduction – With no engine downsizing: 3.5 % increase in EPA combined MPG (9% improvement in performance level) – Engine down‐sized to maintain base vehicle performance: 6.5% increase in EPA combined MPG • Similar results for gasoline and diesel engine vehicles
Fuel Efficiency: Key Takeaway By reducing power requirements with aluminum, vehicles are more affordable and reduce fuel consumption without the loss of performance capabilities.
Aluminum and The Environment Ken Martchek, manager of Life Cycle & Environmental Sustainability Alcoa
Aluminum and the Environment • Environmental issues such as climate change are a growing subject of concern and customer choice
Aluminum and the Environment • The Aluminum industry has Global, Voluntary Objectives Include: established and reports • By 2010: – An 80% reduction in PFC greenhouse annually on global, gas emissions per ton of AL voluntary improvement – A minimum of a 33% reduction in objectives to address fluoride emissions per ton of AL environment issues – A 10% reduction in average smelting energy usage per ton AL – Implementation of ISO Environmental• Learn more at Management Systems in 95% of IAI http://www.world members plants ‐aluminium.org/ • Monitor annual AL shipments for use in Sustainability transport to track aluminum’s contribution through lightweighting • Report regularly on global AL recycling performance
Aluminum and the Environment: Production The aluminum industry is the world’s largest user of renewable energy
Aluminum and the Environment: Production Making progress in reducing its “carbon footprint” London, UK (October 2007) “The International Aluminium Institute reported today industry survey results showing a 14 percent reduction in total direct greenhouse gas emissions from the production processes of primary aluminum, between 2000 and 2005, despite a 20 percent growth in primary aluminum production covered in the survey. “
Aluminum and the Environment: Production The energy required to produce aluminum is small relative to energy used by vehicles (USAMP) 55% of aluminum used to produce today’s cars is produced from recycled metal Recycled aluminum uses 95% less energy to produce than primary aluminum
Aluminum and the Environment: Use in Vehicles Using high strength to mass aluminum reduces weight and improves fuel economy
Aluminum and the Environment: End of Vehicle Life • Over 90% of aluminum is recovered from scrap vehicles • Aluminum is one of the most durable and recyclable materials.
Aluminum and the Environment: Full Cycle Assessment • “Improving Sustainability in the Transport Sector” peer‐reviewed study published early 2008 • “The application of aluminum in passenger vehicles and light trucks manufactured in model year 2006 will lead to potential savings of: – 14.5 billion gallons of gasoline and – Approximately 140 million tons of CO2eq emissions over the lifecycle of these vehicles. Source: IAI Study 2008
Example: China City Bus Partnership with Yutong bus of ZhengZhou, China Launched in Beijing Early 2008 Weight 7% Fuel 90 mt of CO2 Reduction of Efficiency Lifetime 1125 Kg (10%)Value – Ecological • Reduction in CO2 emissions • Reduced road surface wear and tear Value – Financial • 7% less fuel • Maintenance savings (tires, brakes, suspension) • Improved corrosion resistance • Payback of 2‐3 years
Transport Model The “Transport Model” can be assessed http://www.world‐aluminium.org/Downloads/Publications/Most+recent • Input Your Own Case Study and Assumptions!
Environment: Key Takeaway Aluminum producers are reducing their ecological impacts. Utilizing aluminum in vehicles in place of more dense materials can help reduce the carbon footprint of vehicles.
Aluminum and Safety Randall Scheps, marketing director of Ground Transportation Alcoa
A Few Basic Safety Facts • Aluminum can build a safer car than steel ‐ Audi A8 – one of the safest vehicles on the road • Secondary benefits: W/t = 60...80 ‐ Handling (accident avoidance) W = width t = wall thickness Aluminum advantages Mass Specific EA (kJ/kg) ‐ Braking distance reduction • Direct benefits: Steel ‐ Absorbs more energy, pound for pound, than steel 1 2 3 4 5 6 7 ‐ Predictable deformation t ‐ Not strain‐rate sensitive W ‐ Extruded structures – design flexibility ‐ Better crash compatibility – reduce weight, not size
DRI Study Overview • Objective of the DRI (Dynamic Research Inc.) study: ‐ Interplay of vehicle weight vs. size in occupant protection • Methodology: ‐ Real‐world crash data from 3500 collisions ‐ Car to SUV, SUV to SUV, and SUV to fixed obstacle ‐ NCAP pulse and NASS/CDS descriptors ‐ ELU (Injury Index) as proxy for occupant safety • Scenarios: ‐ 20% weight reduction – no length reduction ‐ 4 inch length increase – no weight increase
DRI Results • Adding crush space without adding weight improves ELU 27% • Reducing weight further improves fleet safety SUV to Car Crashes
DRI Results 38.8820% Reduced Weight SUV and Conventional Cars
Crush Rail Example • 56% mass savings vs. mild steel – ( 38% vs. HSS ) • Lower peak loads • Consistent crush performance at all speeds Aluminum Rail Crush Load (kN) Steel Rail Crush Distance (mm)
Taper and Flare Example • 35‐50% higher mean crush load • Low peak loads • Nearly 100% utilization of crush rail length 125 Load due to Taper (This level is not present during crash)Crush Force (kN) 100 Taper-Flare Steady Sate Load • Allows shorter front end • Crush load optimized 50 independent of the rail Axial Folding of Same Section thickness 50 100 150 200 250 Crush Distance (mm) • Not possible in steel
Knee Bolster Example Aluminum can play a key role in energy management in vehicle interiors Example: • Extruded knee bolster consolidates 3 parts into 1 • 48% weight reduction vs. steel • 50th percentile male unbelted sled test passed for a N. American OEM
Safety: Key Takeaways • Size – not weight – is best determinant of vehicle safety • Aluminum can safely take weight out • Aluminum performs as well, if not better than steel in crash • Aluminum offers design flexibility and innovative solutions for energy management
Automakers Lighten Up Daimler AG GM “Every new Mercedes‐Benz model “The company will use different will be 5 percent lighter than its materials, such as more magnesium predecessor.” and aluminum, to make its vehicles lighter and more fuel‐efficient.” Ford “Each Ford Motor Co. model will Land Rover lose 250 to 750 pounds depending “The LRX was engineered to make it on its market segment. Cutting one of the cleanest vehicles in its weight will be more important to class ‐‐ its lower weight and reduced CAFE compliance than some touted aerodynamic drag aid fuel efficiency fuel‐saving technologies.” and reduce C02 emissions.” Nissan Volkswagen “Nissan will cut the weight of its “Automakers are substituting vehicles by an average of 15% over aluminum or plastics for steel the next seven years as it seeks to wherever possible to reduce vehicles improve fuel efficiency.” weight.”