What’s New in Engine Research What’s New in Engine Research Mark Musculus Engine Combustion Department Combustion Research Facility Sandia National Laboratories, Livermore, Ca Funded by U.S. Department of Energy Program Managers: Gurpreet Singh and Kevin Stork SoCal Science Café, Newport Beach, CA April 7, 2007
Energy and Oil in the U.S. Energy and Oil in the U.S. Total U.S. energy from oil (%):…………….. ___% 40 Infrastructure U.S. transportation energy from oil:……….. ___% 96 Imported oil share of U.S. trade deficit:…… ___% 30 Economics Oil price increase in 1973 embargo:………. _____% +350 U.S. imported oil in 1973:…………………… ___% 36 National Security 66 U.S. imported oil in 2005:…………………… ___% CO 2 increase from 0 AD to 1800 AD:.......... _____% near 0 Climate CO 2 increase from 1800 AD to 1900 AD:.... __% 4 Change CO 2 increase from 1900 AD to 2000 AD:.... ___% 25 118 Stage 1 smog alert days in L.A.,1975:......... ____ Air Pollution 0 Stage 1 smog alert days in L.A., 2000:........ ___
Reducing Oil Problems through Engine Efficiency Reducing Oil Problems through Engine Efficiency U.S. Department of Energy goal for engine fuel-efficiency improvement is 50% increase. This would reduce oil usage by 4 Million Barrels / Day (out of 20), which is equivalent to: Infrastructure 30% reduction of oil usage for transportation 12% reduction of our trade deficit Economics 30% reduction of our oil imports Nat’l Security Turn back the clock on CO 2 emissions by 10 years Climate The challenge is to improve efficiency Air Pollution while continuing to improve air quality
Engine Efficiency Depends on Compression Ratio Engine Efficiency Depends on Compression Ratio • Most engines have 4, 6, or 8 cylinders, each with a piston that goes up and down. • The combustion chamber is above the piston, where the fuel burns. • The compression ratio (R) is the maximum combustion chamber volume divided by the minimum combustion chamber volume: • R = V1 / V2 • Higher compression ratios have higher efficiencies. So, one BIG way to increase engine efficiency is to increase the compression ratio.
So Why Don’t They Just … So Why Don’t They Just … Increase the Compression Ratio? Increase the Compression Ratio? n In a gasoline engine, fuel is mixed with air before compression. n The fuel must burn only when ignited by the spark plug, at the proper time. n Higher compression = higher temperature. n Too high compression ratios can ignite fuel before the spark, reducing efficiency explosive combustion (knock). and causing … – For 87 octane gas, max. compression ratio = 9. – With higher octane premium, we could use higher that is very expensive! compression ratios, but … n So, compression ratio must stay low if the fuel is mixed with air BEFORE compression.
So Why Don’t They Just … So Why Don’t They Just … Mix in the Fuel AFTER Compression? Mix in the Fuel AFTER Compression? n They do, in a Diesel engine! Fuel is injected after compression, so the fuel cannot burn too soon! n Diesel compression ratios = 16-22 , so efficiency is much higher. n Problems: (1) high temperatures and (2) poor fuel-air mixing cause much higher air pollution than gasoline engines. n But wait, gasoline engines also have high temperatures, yet they have low air pollution! – Q: Why? – A: Better fuel-air mixing and … THREE-WAY CATALYTIC CONVERTERS!
So Why Don’t They Just … So Why Don’t They Just … Put 3-Way Catalytic Converters on Diesel Engines? Put 3-Way Catalytic Converters on Diesel Engines? 3-way catalytic converters only work when fuel and air are n balanced, with just enough oxygen in the air to burn with the fuel. In a diesel, fuel doesn’t have enough time to completely mix with n all of the air, so some extra air is always left over. We do not yet have such a simple 3-way catalytic converter that n works as efficiently with left-over air, though it is being researched. So, currently, our choices are: n 2. Efficient diesel engine, but 1.Clean gasoline polluting from poor mixing engine, but low and no catalytic converter. compression ratio, so low efficiency.
So Why Don’t They Just … So Why Don’t They Just … Design a New Kind of Engine? Design a New Kind of Engine? They do! In collaboration with the U.S. automotive industry, n Sandia National Laboratories is researching two new engines: 1. “Homogeneous Charge Compression Ignition (HCCI)” ( gasoline engine with high compression ratio) � Add more air so fuel won’t ignite too soon at high compression ratio, remove spark plug (!), & ignite fuel by compression (more like diesel) 2. “Low-Temperature Combustion Diesel (LTC-Diesel)” (diesel engine with lower temperatures and better mixing) � Use exhaust-gas recirculation (EGR) to reduce temperature, and inject fuel during compression for better mixing (more like gasoline) To control either of these new engines and achieve high efficiency with low pollution, we need to understand how fuel mixes with air, ignites, and burns inside the engine.
Engine Research at Sandia National Laboratories Engine Research at Sandia National Laboratories n Our goal is to provide the fundamental science-base for engine combustion. n We use specially modified engines with high-strength windows to view fuel mixing with air, ignition, combustion, and pollutant formation inside the engine using lasers and high-speed cameras. n Strong interaction and collaboration with universities, industry, and other national labs.
Diesel Combustion Movie Diesel Combustion Movie Eight-hole fuel injector squirting out jets of fuel that burn inside the engine
Advancing the Science-Base of Combustion Advancing the Science-Base of Combustion Using Laser and Optical Diagnostics Using Laser and Optical Diagnostics * Based on research of John Dec, Sandia National Laboratories
HCCI Engine Combustion Movie HCCI Engine Combustion Movie Distributions of fuel and temperature inside the engine cause different regions to ignite at different times * Data courtesy of John Dec, Sandia National Laboratories
Impact of Engine Research Impact of Engine Research at Sandia National Laboratories at Sandia National Laboratories n Cummins designed their 2007 low- emissions LTC-Diesel engine using computer modeling and analysis. – After-the-fact testing only. – Significantly reduced development time and cost. – Computer models could only be formed using the science-base of ISB (6.7 liter diesel) diesel combustion fundamentals. Figure Courtesy of Cummins Inc. n In February 2007, GM announced new demonstration HCCI engine with up to 50% greater fuel efficiency. – Not ready for market yet, but prospects are promising. n Much work to be done - the science-base for high-efficiency low-emissions engines is still needed to aid development.
Concluding Remarks Concluding Remarks n Engine efficiency improvements are important for both stand-alone engines and electric hybrid vehicles. n A major challenge is that fuels in the market are changing at the same time as engines – a “Dual Revolution.” – Bio-fuels, tar sands, oil shale, gas/coal to liquids, hydrogen, etc. – New engines will need to be compatible with many fuels. n A renewable, clean liquid hydrocarbon future is possible. n Sandia National Laboratories research includes fuels, combustion, computer modeling, and much more!
Combustion Research Facility Combustion Research Facility Sandia National Labs, Livermore, California Sandia National Labs, Livermore, California "The mission of the CRF is to conduct a broad range of basic and applied research and development in combustion science and technology. We aim to improve our nation's ability to utilize and control combustion processes." n Facility built in 1980 n 100 full-time employees n 100 visitors per year – Post-docs – University faculty – Undergraduate interns – Graduate students – Industrial collaborators Visitors bring technical knowledge and skills. The CRF provides access to facility equipment, resources, and a knowledge base of combustion http:/ / www.c a.sandia.go v/ c rf/ re se arc h/ inde x.php o r Go o gle “Co mbustio n Re se arc h F ac ility”
Conclusion and Invitation Conclusion and Invitation This presentation provided only a tiny glimpse of the breadth of n activities at Sandia National Laboratories, both in engines and in other research and development. If you are interested in learning more, visiting, or working at the n Sandia National Laboratories, talk to me or visit online: http://www.ca.sandia.gov/crf/research/index.php or Google “Sandia National Laboratories” or Google “Combustion Research Facility”
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