Evolution of IC Engines

8/3/2019 Evolution of IC Engines

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The Evolution of the Internal CombustionThe Evolution of the Internal CombustionEngine and Future Design Challenges:Engine and Future Design Challenges:

Performance, Efficiency, EmissionsPerformance, 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 90089Los Angeles, CA 90089--1453 USA1453 USA

http://carambola.usc.eduhttp://carambola.usc.edu


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University of Southern CaliforniaUniversity of Southern California -- Department of Aerospace and Mechanical EngineeringDepartment of Aerospace and Mechanical Engineering

OutlineOutline

Why gasolineWhy gasoline--fueled premixedfueled premixed--charge IC engines?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


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Why premixedWhy premixed--charge IC engines?charge IC engines?

AlternativesAlternatives External combustionExternal combustion -- "steam engine," "Stirling cycle""steam engine," "Stirling cycle"

Heat transfer is too slow ( 100x slower than combustion)Heat transfer is too slow ( 100x slower than combustion)

10 B10 B--747 engines large coal747 engines large coal--fueled electric power plantfueled electric power plant

Electric vehicles (EVs)Electric vehicles (EVs)

Batteries are heavy 1000 lbs/gal of gasoline equivalentBatteries 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"Zero emissions" myth -- EVsEVs exportexport pollutionpollution

Environmental cost of battery materialsEnvironmental cost of battery materials

Possible advantage: makes smaller, lighter, more streamlined carsPossible advantage: makes smaller, lighter, more streamlined cars

acceptable to consumersacceptable to consumers

Prediction: eventual conversion of electric vehicles to gasoline powerPrediction: eventual conversion of electric vehicles to gasoline power(>100 miles per gallon)(>100 miles per gallon)


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Zero emission electric vehiclesZero emission electric vehicles


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Why premixedWhy premixed--charge IC engines?charge IC engines?

Alternatives (continued)Alternatives (continued) SolarSolar

Need 30 ft x 30 ft collector for 15 hp (Arizona, high noon, midNeed 30 ft x 30 ft collector for 15 hp (Arizona, high noon, mid--

summer)summer)

NuclearNuclear

Who are we kidding ???Who are we kidding ???

MoralMoral -- hard to beat gasolinehard to beat gasoline--fueled IC engine forfueled IC engine for Power/weight & power/volume of enginePower/weight & power/volume of engine

Energy/weight & energy/volume of liquid hydrocarbon fuelEnergy/weight & energy/volume of liquid hydrocarbon fuel

Distribution & handling convenience of liquidsDistribution & handling convenience of liquids


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18591859 -- Oil discovered in PennsylvaniaOil discovered in Pennsylvania

18761876 -- PremixedPremixed--charge 4charge 4--stroke enginestroke engine -- OttoOtto 1st practical IC engine1st practical IC engine

Power: 2 hp;Weight: 1250 poundsPower: 2 hp;Weight: 1250 pounds

Comp. ratio = 4 (knock limited), 14% efficiency (theory 38%)Comp. ratio = 4 (knock limited), 14% efficiency (theory 38%)

Today CR = 8 (still knock limited), 30% efficiency (theory 52%)Today CR = 8 (still knock limited), 30% efficiency (theory 52%)

18971897 -- NonpremixedNonpremixed--charge enginecharge engine -- DieselDiesel -- higher efficiency due tohigher efficiency due to Higher compression ratio (no knock problem)Higher compression ratio (no knock problem)

No throttling lossNo throttling loss -- use fuel/air ratio to control poweruse fuel/air ratio to control power


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Premixed vs. nonPremixed vs. non--premixed charge enginespremixed charge engines

Flame front Fuel spray flame

Premixed charge

(gasoline)Non-premixed charge

(Diesel)

Spark plug Fuel injector

Fuel + air mixture Air only


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19231923 -- Tetraethyl leadTetraethyl lead -- antianti--knock additiveknock additive Enable higher CR in OttoEnable higher CR in Otto--type enginestype engines

19521952 -- A. J. HaagenA. J. Haagen--SmitSmit NO + UHC + ONO + UHC + O22 + sunlight+ sunlight pp NONO22 + O+ O33(from exhaust) (brown) (irritating)(from exhaust) (brown) (irritating)

1960s1960s -- Emissions regulationsEmissions regulations Detroit wont believe itDetroit wont believe it Initial stopInitial stop--gap measuresgap measures -- lean mixture, EGR, retard sparklean mixture, EGR, retard spark

Poor performance & fuel economyPoor performance & fuel economy

1973 & 19791973 & 1979 -- The energy crisesThe energy crises Detroit takes a bathDetroit takes a bath


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19751975 -- Catalytic converters, unleaded fuelCatalytic converters, unleaded fuel Detroit forced to buy technologyDetroit forced to buy technology More aromatics (e.g., benzene) in gasolineMore aromatics (e.g., benzene) in gasoline -- high octane but carcinogenic,high octane but carcinogenic,

sootsoot--producingproducing

1980s1980s -- Microcomputer control of enginesMicrocomputer control of engines Tailor operation for best emissions, efficiency, ...Tailor operation for best emissions, efficiency, ...

1990s1990s -- Reformulated gasolineReformulated 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!!!


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Things you need to understand before ...Things you need to understand before ...

you invent the zeroyou invent the zero--emission, 100 mpg 1000 hp engine,emission, 100 mpg 1000 hp engine,

revolutionize the automotive industry and shop for yourrevolutionize the automotive industry and shop for yourretirement home on the French Rivieraretirement home on the French Riviera

Room for improvementRoom for improvement -- factor of 2 in efficiencyfactor of 2 in efficiency Ideal Otto cycle engine with CR = 8: 52%Ideal Otto cycle engine with CR = 8: 52%

Real engine: 25Real engine: 25 -- 30%30% Differences because ofDifferences because of

Throttling lossesThrottling losses

Heat lossesHeat losses

Friction lossesFriction losses


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Room for improvementRoom for improvement -- infinite in pollutantsinfinite in pollutants Pollutants are aPollutants are a nonnon--equilibriumequilibrium effecteffect

Burn: Fuel + OBurn: Fuel + O22 + N+ N22 pp HH22O + COO + CO22 + N+ N22 + CO + UHC + NO+ CO + UHC + NO

OK OK OK Bad Bad BadOK OK OK Bad Bad Bad

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 pp HH22O + COO + CO22 + N+ N22...but how to slow the expansion and eliminate heat loss?...but how to slow the expansion and eliminate heat loss?

Worst problems: cold start, transients, old or outWorst problems: cold start, transients, old or out--ofof--tune vehiclestune vehicles -- 90% of90% of

pollution generated by 10% of vehiclespollution generated by 10% of vehicles


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Room for improvementRoom for improvement -- very little in powervery 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

Friction loss, mechanical strengthFriction loss, mechanical strength -- limits RPMlimits RPM Slow burnSlow burn

Majority of power is used to overcome air resistanceMajority of power is used to overcome air resistance -- smaller, moresmaller, more

aerodynamic vehicles beneficialaerodynamic vehicles beneficial


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Ideas for improvementIdeas for improvement -- alternative fuelsalternative fuels

Natural gasNatural gas

+ Somewhat cleaner than gasoline, non+ Somewhat cleaner than gasoline, non--toxictoxic+ High octane without refining or additives ( 110)+ High octane without refining or additives ( 110)

+ No cold start problem+ No cold start problem

+ Abundant, domestic supply+ Abundant, domestic supply

+ Cheap ( 1/5 gasoline)+ Cheap ( 1/5 gasoline)

+ Half the CO+ Half the CO22 emission of EVs charged with coalemission of EVs charged with coal--generated electricitygenerated electricity+ Dual+ Dual--fuel (gasoline + natural gas) easily accommodatedfuel (gasoline + natural gas) easily accommodated

-- 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 territoryAttractive for fleet vehicles with limited territory


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Ideas for improvementIdeas for improvement -- alternative fuelsalternative fuels

AlcoholsAlcohols

+ Slightly cleaner than gasoline+ Slightly cleaner than gasoline+ High octane ( 95)+ High octane ( 95)

-- Not costNot cost--effective without price subsidyeffective without price subsidy

-- Lower storage density (methanol 1/2 gasoline)Lower storage density (methanol 1/2 gasoline)

-- Toxic combustion products (aldehydes)Toxic combustion products (aldehydes)

Attractive to powerful senators from farm statesAttractive to powerful senators from farm states

HydrogenHydrogen+ Ultimate clean fuel+ Ultimate clean fuel

+ Excellent combustion properties+ Excellent combustion properties

+ Ideal for fuel cells+ Ideal for fuel cells-- Very low storage density (1/10 gasoline)Very low storage density (1/10 gasoline)

-- Need to manufactureNeed to manufacture -- usually from electricity + Husually from electricity + H22OO

Attractive when we have unlimited cheap clean source of electricity andAttractive when we have unlimited cheap clean source of electricity and

breakthrough in hydrogen storage technologybreakthrough in hydrogen storage technology


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Ideas for improvementsIdeas for improvements -- reduce heat lossreduce 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

Wrinkle flame (premixed charge, gasoline)Wrinkle flame (premixed charge, gasoline)

Disperse fuel droplets (nonpremixed charge, Diesel)Disperse fuel droplets (nonpremixed charge, Diesel)

"Inverse"Inverse--engineer" engine for lowengineer" engine for low--turbulenceturbulence

GasolineGasoline -- electricallyelectrically--induced flame wrinkling?induced flame wrinkling? DieselDiesel -- electrostatic dispersion of fuel in chamber?electrostatic dispersion of fuel in chamber?


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Electrostatic spraysElectrostatic sprays


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IdeasIdeas -- reduce throttling lossreduce throttling loss

PremixedPremixed--charge IC engines frequently operated at lower thancharge IC engines frequently operated at lower than

maximum torque output (throttled conditions)maximum torque output (throttled conditions) Throttling adjusts torque output of engines by reducing intakeThrottling adjusts torque output of engines by reducing intake densitydensity

through decrease inthrough decrease in pressurepressure (( PP == VVRT)RT)

Throttling losses substantial at part loadThrottling losses substantial at part load

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1

Efficiency(throttled)/

Efficiency(no

throttle)

Fraction of maximum load


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The TPCE conceptThe TPCE concept

Throttleless PremixedThrottleless Premixed--charge Engine (TPCE)charge Engine (TPCE)

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 VV

Preheat provides leaner lean misfire limitPreheat provides leaner lean misfire limit -- use air/fuel ratio AND intakeuse air/fuel ratio AND intake

temperature to control torquetemperature to control torque

Provides DieselProvides Diesel--like economy with gasolinelike economy with gasoline--like powerlike power

Retrofit to existing engines possible by changing only intake, exhaust,Retrofit to existing engines possible by changing only intake, exhaust,

& control systems& control systems


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TPCE implementation conceptTPCE implementation concept

FUEL

AIR

ADJUSTABLE

FUEL CONTROL VALVE

CARBURETOR

DIVERTER VALVE

EXHAUST

HEAT EXCHANGER

CONVENTIONAL

4-STROKE ENGINE


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ResultsResults

Substantially improved fuel economy (up to 16 %) compared toSubstantially improved fuel economy (up to 16 %) compared to

throttled engine at same power & RPMthrottled engine at same power & RPM

1

1.05

1.1

1.15

1.2

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Natural gasGasolineTheory

Efficiency(b

estTPCE)/Efficiency(throttled)

Load (fraction of maximum)


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ResultsResults

NONOxx performanceperformance

< 0.8 grams per kW< 0.8 grams per kW--hr (10 x lower than throttled engine )hr (10 x lower than throttled engine )< 0.2 grams per mile for 15 hp road load @ 55 mi/hr< 0.2 grams per mile for 15 hp road load @ 55 mi/hr -- half of California 2001half of California 2001

standardstandard

CO and UHC comparable to throttled engineCO and UHC comparable to throttled engine


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Programmable intake/exhaust valve timingProgrammable intake/exhaust valve timing

Electrical/hydraulic valve actuationElectrical/hydraulic valve actuation Choose open/close timing to optimize power, emissions, efficiencyChoose open/close timing to optimize power, emissions, efficiency -- cancan

eliminate throttling losseliminate throttling loss


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Homogeneous ignition engineHomogeneous ignition engine -- controlled knockingcontrolled knocking

Burn much leaner mixturesBurn much leaner mixtures -- higher efficiency, lower NOhigher efficiency, lower NOxx Need to abandon traditional Hail, Mary combustion control strategyNeed to abandon traditional Hail, Mary combustion control strategy


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IdeasIdeas -- improved leanimproved lean--limit operationlimit operation

Recent experiments & modelling suggest leanRecent experiments & modelling suggest lean--limit rough operation islimit rough operation is

aa chaoticchaotic processprocess Feedback via exhaust gas residualFeedback via exhaust gas residual

Could optimize spark timingCould optimize spark timing on a cycleon a cycle--toto--cycle basiscycle basis

Need to infer state of gas & predict burn time for next cycleNeed to infer state of gas & predict burn time for next cycle -- needneed inin--

cylindercylindersensorssensors


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ConclusionsConclusions

IC engines are the worst form of vehicle propulsion, except for all theIC engines are the worst form of vehicle propulsion, except for all the

other formsother forms Despite over 100 years of evolution, IC engines are far from optimizedDespite over 100 years of evolution, IC engines are far from 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 nearEasiest near--term change: naturalterm change: natural--gas vehicles for fleet & commutersgas vehicles for fleet & commuters

LongerLonger--term solutions mostly require improved (cheaper)term solutions mostly require improved (cheaper) SensorsSensors (especially in(especially in--cylinder temperature, pressure)cylinder temperature, pressure)

ActuatorsActuators (especially intake valves)(especially intake valves)


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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 METRANS and especially METRANS

Evolution of IC Engines

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