Improving Engine Efficiency and Fuels: An Overview. John B. Heywood. Massachusetts Institute of Technology

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1 Improving Engine Efficiency and Fuels: An Overview John B. Heywood Sun JaeProfessor of Engineering, Emeritus Massachusetts Institute of Technology Presentation at CRC Advanced Fuel and Engine Efficiency i Workshop, Baltimore, MD February 24 26, 2014

2 Our group has authored relevant Papers and Reports On the Road Towards 2050 REDUCINGTRANSPORTATION S PETROLEUM CONSUMPTION AND GHG EMISSIONS REPORT 2013 John Heywood Don KacKenzie Ingrid Bonde Akerlind Alice Chao Valerie Karplus David Keith Stephen Zoepf Sloan Autom otive Laboratory MIT Energy Initiative MITMassachusetts Institute of Technology 2 2/24 26/2014

3 Important Propulsion System and Transportation Energy Paths Forward 1. Improving mainstream technology More efficient engines (e.g. turbocharged downsized gasoline and diesel engines, charge sustaining hybrids) More efficient transmissions Vehicleweight, eight drag, andperformance reduction Liquid fuels from biomass Liquid fuels from shale oil, coal, natural gas 2. Transitioning to new energy sources Electricity it (PHEVs, BEVs) Natural gas (spark ignition engine) Hydrogen (fuel cells) 3 2/24 26/2014

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5 Relative Fuel Consumptions (Tank to Wheels): Different Propulsion System Vehicles 5 2/24 26/2014

6 Summary of Potential at the Vehicle Level 1. Improving mainstream engine and hybrid technology, and vehicle light weighting, have potential for some 50 percent reduction in vehicle fuel consumption by Greenhouse gas emissions reduction potential, full life cycle analysis, is about 40 percent. 3. Higher octane gasoline: potentialfor useful benefits. 4. Biofuels? Useful, though likely limited in scale. 5. Plug in hybrid technology significantly more promising path to increased electrification than BEVs: battery performance and cost are major barriers. 6. Fuel cell hybrid technology and hydrogen appear to be lowest cost alternative option: low GHG emitting hydrogen supply and distribution major barrier. 6 2/24 26/2014

7 Well-to-Wheels GHG Emissions Data: Average New U.S. Car in 2030 a Dependent on the % miles electrical and electrical supply system b FCEV Lower number with Clean H 2 (with carbon capture and sequestration) c Dependent on the CO 2 intensity of electricity d Dependent on biomass GHG intensity 7 2/24 26/2014

8 Technology Market Deployment Over Time (U.S.) Sales market share modal inputs to Source: Bastani, Heywood, Hope (2012) 2/24 26/2014

9 Results: U.S. LDV Fleet TTW Fuel Use out to 2050 U.S. Fleet Fuel Consumption [Bil L gasoline equivalent/year] mean, and uncertainty profiles, over time Source: Bastani, Heywood, Hope (2012) 9 2/24 26/2014

10 Estimated time scales for technology impact Source: Heywood et al. On the Road in 2035 (2008) 10 2/24 26/2014

11 U.S. Context Regarding Fuel Octane 1. Obvious driver: higher octane fuel, higher compression ratio, higher engine efficiency. 2. With spread of turbocharged gasoline engines, triple benefit: higher compression ratio, higher boost, and engine downsizing. 3. Growing consensus that improving gasoline engine efficiency is our primary nearer term fuel use and GHG reduction option 4. Alternative fuel supplies developing slowly: should use full octane potential of gasoline and ethanol 5. Petroleum-based fuel demand and GHG emissions reduction targets require we explore all potential opportunities 11 2/24 26/2014

12 Practical issues behind fuel octane 1. If gasoline octane (RON) is raised: Need the new gasolines to be drop-in fuels, avoid producing another gasoline grade in parallel to current grades, and avoid wasting octane Need a plausible transition path from current gasoline grades to significant volume of high octane grades 2. Suggests: A straightforward transition to new grades would be increase supply of premium gasoline (RON 98) and decrease supply of regular gasoline (RON 91) in parallel 12 2/24 26/2014

13 Recently Completed Study of Transition from Regular (92 RON) to Premium (98 RON): U.S. 1. Used engine and engine-in-vehicle simulations to estimate improved vehicle fuel consumption from higher compression ratio and boost, with engine downsizing, for an increase of 6 RON fuel octane. 2. Used our U.S. in-use vehicle fleet model methodology and reference scenario assumptions 3. Critical questions: the compression ratio increase and resulting engine efficiency increase, from higher octane fuel and boost/downsizing trade off 4. The refinery impact of this fuel transition is modest 13 2/24 26/2014

14 Projected U.S. in-use fleet fuel consumption reduction of up to 5% by % of fuel is then 98 RON. Source: Chow and Heywood, SAE paper /24 26/2014

15 Be careful with attitudes and words Replace With never all should happen optimistic loose average ambiguous numbers tank to wheels small vehicles not yet ready most might happen realistic clearly defined average well defined numbers well to wheels less big vehicles 15 2/24 26/2014

16 Extra Slides 16 2/24 26/2014

17 U.S. fleet model results: Number of vehicles and in-use fuel consumption by fuel and engine type. Source: Chow and Heywood, SAE paper /24 26/2014

18 Science and practice behind octane: Fuels (Continued) Allow sensitivity of all gasoline grades to float, maybe increase, to maximize octane index RON benefit Use the available ethanol s high octane to best advantage by blending with gasoline, and with direct fuel-injection technology, to benefit from ethanol s evaporative charge-cooling effect Alternative approach: Use higher ethanol-gasoline blends as knock-suppressing fuel in gasoline engines when gasoline would knock (Ethanol Boost System s two-tank tank approach or or use on vehicle membrane separation of fuel into high and low octane streams used as needed 18 2/24 26/2014

19 Engine/Vehicle opportunities and challenges 1. Continue transition to direct-injection fueling to maximize benefits of higher octane 2. Optimize combination of DI and turbocharging that provides largest part-load gasoline consumption benefit (h (throughh compression ratio and boost level increases) with higher octane gasoline 3. Will need to strengthen the engine for the higher mechanical and thermal loadings 19 2/24 26/2014

20 Summary 1. Use Research Octane Number to characterize and certify knock resistance of fuels. 2. Remove the Motor Octane Number requirement constraint: allow fuel sensitivity to vary. 3. Most pragmatic approach for U.S. from vehicle and customer perspective: blend 10-15% 15% ethanol to produce increasing volume of 98 RON high sensitivity high octane gasoline (the new fuel) and decrease volume of 91 RON regular; increase compression ratio and boost. 20 2/24 26/2014

21 Summary (Continued) 4. Alternative Approach: Use duel fuel EBS two fuel tanks knock-free engine concept; (1) loweroctane gasoline base fuel, with (2) higher-octane fuel (e.g., E50, E85) when knock with gasoline would occur. Use higherh compression ratio, higher boost, downsized engine. 5. Both approaches improve fuel consumption (FC) and reduce GHG emissions impacts: Approach (3) gives 5% FC reduction relative to today s NASI engine, and 7% relative to today s TC engine. Approach (4) gives about 10% FC reduction relative to today s turbocharged DI gasoline engine. 21 2/24 26/2014