The Evolution of the InternalThe Evolution of the InternalCombustion Engine and FutureCombustion Engine and FutureDesign Challenges:Design Challenges:Performance, Efficiency, EmissionsPerformance, Efficiency, EmissionsPaul D. Ronney Paul D. Ronney Dept. of Aerospace & Mechanical Eng. Dept. of Aerospace & Mechanica l Eng. University of Southern California University of Southern California Los Angeles, CA 90089-1453 USA Los Angeles, CA 90089-1453 USA http://carambola.usc.eduhttp://carambola.usc.edu
Transcript
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 1/26
The Evolution of the Internal The Evolution of the Internal
Combustion Engine and Future Combustion Engine and Future Design Challenges: Design Challenges: Performance, Efficiency, Emissions Performance, Efficiency, Emissions
Paul D. RonneyPaul D. Ronney
Dept. of Aerospace & Mechanical Eng.Dept. of Aerospace & Mechanical Eng.
University of Southern CaliforniaUniversity of Southern California
Los Angeles, CA 90089-1453 USALos Angeles, CA 90089-1453 USA
http://carambola.usc.edu http://carambola.usc.edu
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 2/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Outline Outline
• Why gasoline-fueled premixed-charge IC engines?Why gasoline-fueled premixed-charge IC engines?•
History and evolutionHistory and evolution• Things you need to understand about IC engines before ...Things you need to understand about IC engines before ...• Ideas for improvementsIdeas for improvements• ConclusionsConclusions
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 3/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Why premixed-charge IC engines? Why premixed-charge IC engines?
• AlternativesAlternatives•
External combustion - "steam engine," "Stirling cycle"External combustion - "steam engine," "Stirling cycle"» Heat transfer is too slow ( 100x slower than combustion)≈Heat transfer is too slow ( 100x slower than combustion)≈
» 10 B-747 engines large coal-fueled electric power plant≈10 B-747 engines large coal-fueled electric power plant≈
• Electric vehicles (EVs)Electric vehicles (EVs)» Batteries are heavy 1000 lbs/gal of gasoline equivalent≈Batteries are heavy 1000 lbs/gal of gasoline equivalent≈
»
Fuel cells better, but still nowhere near gasolineFuel cells better, but still nowhere near gasoline» "Zero emissions" myth - EVs"Zero emissions" myth - EVs exportexport pollutionpollution» Environmental cost of battery materialsEnvironmental cost of battery materials» Possible advantage: makes smaller, lighter, morePossible advantage: makes smaller, lighter, more
streamlined cars acceptable to consumersstreamlined cars acceptable to consumers»
Prediction: eventual conversion of electric vehicles toPrediction: eventual conversion of electric vehicles togasoline power (>100 miles per gallon)gasoline power (>100 miles per gallon)
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 4/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
“ “ Zero emission” electric vehicles Zero emission” electric vehicles
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 5/26
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 6/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
History and evolution History and evolution
• 1859 - Oil discovered in Pennsylvania1859 - Oil discovered in Pennsylvania•
1897 - Nonpremixed-charge engine - Diesel - higher efficiency1897 - Nonpremixed-charge engine - Diesel - higher efficiencydue todue to• Higher compression ratio (no knock problem)Higher compression ratio (no knock problem)• No throttling loss - use fuel/air ratio to control powerNo throttling loss - use fuel/air ratio to control power
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 7/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Premixed vs. non-premixed charge engines Premixed vs. non-premixed charge engines
Flame front Fuel spray flame
Premixed charge(gasoline)
Non-premixed charge(Diesel)
Spark plug Fuel injector
Fuel + air mixtureAir only
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 8/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
History and evolution History and evolution
• 1923 - Tetraethyl lead - anti-knock additive1923 - Tetraethyl lead - anti-knock additive•
Enable higher CR in Otto-type enginesEnable higher CR in Otto-type engines• 1952 - A. J. Haagen-Smit1952 - A. J. Haagen-Smit
• 1973 & 1979 - The energy crises1973 & 1979 - The energy crises• Detroit takes a bathDetroit takes a bath
8/14/2019 Chinu12 - Copy
http://slidepdf.com/reader/full/chinu12-copy 9/26
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Detroit forced to buy technologyDetroit forced to buy technology• More “aromatics” (e.g., benzene) in gasoline - high octane butMore “aromatics” (e.g., benzene) in gasoline - high octane but
• 1980s - Microcomputer control of engines1980s - Microcomputer control of engines• Tailor operation for best emissions, efficiency, ...Tailor operation for best emissions, efficiency, ...
•
1990s - Reformulated gasoline1990s - Reformulated gasoline• Reduced need for aromatics, cleaner(?)Reduced need for aromatics, cleaner(?)• ... but higher cost, lower miles per gallon... but higher cost, lower miles per gallon• Now we find MTBE pollutes groundwater!!!Now we find MTBE pollutes groundwater!!!
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Things you need to understand before ...Things you need to understand before ...
……you invent the zero-emission, 100 mpg 1000 hp you invent the zero-emission, 100 mpg 1000 hp
engine, revolutionize the automotive industry and engine, revolutionize the automotive industry and shop for your retirement home on the French Riviera shop for your retirement home on the French Riviera
• Room for improvement - factor of 2 in efficiencyRoom for improvement - factor of 2 in efficiency• Ideal Otto cycle engine with CR = 8: 52%Ideal Otto cycle engine with CR = 8: 52%•
Real engine: 25 - 30%Real engine: 25 - 30%• Differences because ofDifferences because of
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Things you need to understand before ...Things you need to understand before ...
• Room for improvement - infinite in pollutantsRoom for improvement - infinite in pollutants•
Pollutants are aPollutants are a
non-equilibriumnon-equilibrium
effecteffect
» Burn: Fuel + OBurn: Fuel + O22+ N+ N
22 → HH
22O + COO + CO
22+ N+ N
22+ CO + UHC + NO+ CO + UHC + NO
OK OK OK Bad BadOK OK OK Bad Bad
BadBad» Expand: CO + UHC + NO “frozen” at high levelsExpand: CO + UHC + NO “frozen” at high levels»
With slow expansion, no heat loss:With slow expansion, no heat loss:CO + UHC + NOCO + UHC + NO → HH
22O + COO + CO
22+ N+ N
22
...but how to slow the expansion and eliminate heat...but how to slow the expansion and eliminate heat
loss?loss?• Worst problems: cold start, transients, old or out-of-tuneWorst problems: cold start, transients, old or out-of-tune
vehicles - 90% of pollution generated by 10% of vehiclesvehicles - 90% of pollution generated by 10% of vehicles
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Things you need to understand before ...Things you need to understand before ...
• Room for improvement - very little in powerRoom for improvement - very little in power•
IC engines are air processorsIC engines are air processors» Fuel takes up little spaceFuel takes up little space» Air flow = powerAir flow = power» Limitation on air flow due toLimitation on air flow due to
• ““Choked” flow past intake valvesChoked” flow past intake valves•
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Ideas for improvement - alternative fuels Ideas for improvement - alternative fuels
• Natural gasNatural gas
+ Somewhat cleaner than gasoline, non-toxic+ Somewhat cleaner than gasoline, non-toxic+ High octane without refining or additives ( 110)≈+ High octane without refining or additives ( 110)≈
- Lower energy storage density ( 1/4 gasoline)≈- Lower energy storage density ( 1/4 gasoline)≈
- Lower power ( 7% less)≈- Lower power ( 7% less)≈Attractive for fleet vehicles with limited territory Attractive for fleet vehicles with limited territory
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Ideas for improvement - alternative fuels Ideas for improvement - alternative fuels
• AlcoholsAlcohols
+ Slightly cleaner than gasoline+ Slightly cleaner than gasoline
+ High octane ( 95)≈+ High octane ( 95)≈
- Not cost-effective without price subsidy- Not cost-effective without price subsidy
- Lower storage density (methanol 1/2 gasoline)≈- Lower storage density (methanol 1/2 gasoline)≈
- Very low storage density (1/10 gasoline)- Very low storage density (1/10 gasoline)- Need to manufacture - usually from electricity + H- Need to manufacture - usually from electricity + H22OO
Attractive when we have unlimited cheap clean source of Attractive when we have unlimited cheap clean source of
electricity and breakthrough in hydrogen storage technology electricity and breakthrough in hydrogen storage technology
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Ideas for improvements - reduce heat loss Ideas for improvements - reduce heat loss
• Reduction of heat lossesReduction of heat losses• Heat losses caused by high engine turbulence levelsHeat losses caused by high engine turbulence levels• Need high turbulence toNeed high turbulence to
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Ideas - reduce throttling loss Ideas - reduce throttling loss
• Premixed-charge IC engines frequently operated at lowerPremixed-charge IC engines frequently operated at lower
than maximum torque output (throttled conditions)than maximum torque output (throttled conditions)• Throttling adjusts torque output of engines by reducingThrottling adjusts torque output of engines by reducing
intakeintake densitydensity through decrease inthrough decrease in pressurepressure (( PP == ρ RT)RT)• Throttling losses substantial at part loadThrottling losses substantial at part load
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
U. S. Patent No. 5,184,592U. S. Patent No. 5,184,592• Supported by SCAQMD School Clean Fuels ProgramSupported by SCAQMD School Clean Fuels Program• Preheat air using exhaust heat transfer to reducePreheat air using exhaust heat transfer to reduce ρ• Preheat provides leaner lean misfire limit - use air/fuelPreheat provides leaner lean misfire limit - use air/fuel
ratio AND intake temperature to control torqueratio AND intake temperature to control torque
• Provides Diesel-like economy with gasoline-like power Provides Diesel-like economy with gasoline-like power • Retrofit to existing engines possible by changing only Retrofit to existing engines possible by changing only
intake, exhaust, & control systems intake, exhaust, & control systems
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Results Results
• Substantially improved fuel economy (up to 16 %)Substantially improved fuel economy (up to 16 %)
compared to throttled engine at same power & RPMcompared to throttled engine at same power & RPM
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Results Results
• NONOxx performanceperformance
< 0.8 grams per kW-hr (10 x lower than throttled engine )< 0.8 grams per kW-hr (10 x lower than throttled engine )
< 0.2 grams per mile for 15 hp road load @ 55 mi/hr - half of< 0.2 grams per mile for 15 hp road load @ 55 mi/hr - half of
California 2001 standardCalifornia 2001 standard
• CO and UHC comparable to throttled engineCO and UHC comparable to throttled engine
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Ideas for improvements Ideas for improvements
• Homogeneous ignition engine - controlled knockingHomogeneous ignition engine - controlled knocking• Burn much leaner mixtures - higher efficiency, lower NOBurn much leaner mixtures - higher efficiency, lower NO
xx
• Need to abandon traditional “Hail, Mary” combustion controlNeed to abandon traditional “Hail, Mary” combustion control
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
operation is aoperation is a chaoticchaotic processprocess• Feedback via exhaust gas residualFeedback via exhaust gas residual• Could optimize spark timingCould optimize spark timing on a cycle-to-cycle basis on a cycle-to-cycle basis • Need to infer state of gas & predict burn time for nextNeed to infer state of gas & predict burn time for next
cycle - needcycle - need in-cylinder in-cylinder sensorssensors
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Conclusions Conclusions
• IC engines are the worst form of vehicle propulsion,IC engines are the worst form of vehicle propulsion,
except for all the other formsexcept for all the other forms• Despite over 100 years of evolution, IC engines are farDespite over 100 years of evolution, IC engines are far
from optimizedfrom optimized• Any new idea must consider many factors, e.g.Any new idea must consider many factors, e.g.
• Where significant gains can & cannot be madeWhere significant gains can & cannot be made•
CostCost• Resistance of suppliers & consumers to changeResistance of suppliers & consumers to change
• Easiest near-term change: natural-gas vehicles for fleet &Easiest near-term change: natural-gas vehicles for fleet &
University of Southern California - Department of Aerospace and Mechanical EngineeringUniversity of Southern California - Department of Aerospace and Mechanical Engineering
Thanks to ...Thanks to ...
• USC Dept. of Aerospace & Mechanical EngineeringUSC Dept. of Aerospace & Mechanical Engineering•
Gas Research InstituteGas Research Institute
• South Coast Air Quality Management DistrictSouth Coast Air Quality Management District• …… and especially METRANSand especially METRANS
