Reciprocating Engines OverviewBy Charlie Cote and Bill Ryan

ES106Woodward Industrial Controls

Recip Engine TopicsEngine TypesApplicationsCombustion ProcessCombustion ControlsExhaust EmissionsEngine EfficiencyQuestion & AnswerIntegral CompressorMarine Propulsion

Engine Family Tree

Reciprocating Engine Family

Recip Engine TypesTwo-Stroke Cycle and Four-Stroke CycleFuel TypesGasolineNatural Gas and other gases.Diesel (Light and Heavy)Dual Fuel (Natural Gas/Diesel, Digester/Diesel)Future Fuels (Coal/Water, Orimulsion, etc.)Ignition TypesSpark Diesel

Four-Stroke Cycle EnginesFour Strokes per combustion CycleOnly one Power Stroke every four cylinder strokesTwo full engine crankshaft revolutions for one complete combustion cycleCommon for small to large engines

Four-Stroke CycleIntakeIntake StrokeCompression Stroke

Four-Stroke CyclePower StrokeExhaust StrokeExhaust

Two-Stroke Cycle EnginesTwo Strokes per combustion CycleOne Power Stroke every other cylinder strokeOne full engine crankshaft revolution for one complete combustion cycleMore common for large spark gas engines and small gasoline engines.

Two-Stroke CycleCompressionCombustion

Two-Stroke CycleExhaustExhaustOpensIntake & ScavengingAirOpensGas InjectionAirIntakeExhaustDischarge

Cooper-BessemerGMV Series 2-Cycle Clean-BurnEngine Section

PowerPistonPowerCylinderLinerConnectingRod

Recip Engine ApplicationsOn-Highway Vehicles (autos, trucks, motorcycles, etc.)Off-Highway Machinery (lawn mowers, snowmobiles, farm equipment, construction and mining equipment, etc.)Marine (propulsion and generation)Industrial Pumps Railroad LocomotivesPower Generators (portable and stationary)Compressors (natural gas, CO2 , air, etc.)

Compressor StationYard Valves & Piping

Recip Engine ApplicationsAdvantages of Reciprocating EnginesThey offer a wide range of speed and horsepower to closely match the driven load requirements.Variable speed applicationsMean time between major overhaul is 50,000 hoursLong installed life (50+ years). They work with a wide variety of fuels.Compressors can be mounted integral to the engine and compressed gas services can be mixed.Slight efficiency advantage over turbines (40% - 38%). Advantage increases with smaller sizes (40% - 34%). Nox emissions of 120 ppm comparable to smaller turbines (5 mw). Larger turbines (25-30 mw) produce lower Nox emissions (50 ppm).

Reciprocating Integral Compressor

CompressorCylinder

Recip Engine Rating RangesGasoline Engines31 Worldwide Manufacturers * Kubota, GH100, 2.3 hp, 3200 rpm, 2.2 bore x 1.6 stroke (smallest hp)Lamborghini, L9001, 670 hp, 4000 rpm, 4.15 bore x 3.5 stroke (largest hp) *Refer to Diesel and Gas Turbine Worldwide Catalog, 1998 for a detailed listing of all engine manufacturers.

Recip Engine Rating RangesSpark Gas Engines * 28 Worldwide Manufacturers Arrow Specialty Co, C-46, 400-800 rpm, 5-10 hp (smallest hp)Dresser-Rand, TCVD-20, 330 rpm, 10202 hp, 17.7 bore x 19 stroke (largest hp)

Recip Engine Rating RangesDiesel Engines118 Worldwide Manufacturers * Hatz Diesel, 1B20, 1.9-4.6 hp, 1500-3600 rpm,2.7 bore x 2.44 stroke (smallest hp)MAN B&W Diesel, K98MC, 38487-92046 hp, 84-94 rpm, 38.6 bore x 104.7 stroke (largest hp)CAT Diesel 3500/3600 family, 600-9655 hp (major Woodward customer)

Caterpillar G3516 Tandem Gas Engine Generator set

Recip Engine Rating RangesDual Fuel (Gas/Diesel) Engines * 19 Worldwide Manufacturers Wis-Con Total Power, W2-1250, 1800-3600 rpm, 17.7-30 hp (smallest hp)MAN B&W Diesel, L&V4/60DG, 514 rpm, 7241- 21724 hp, 18.9 bore x 23.6 stroke (largest hp)

2-Cycle, Spark GasReciprocating Engine

BREAKBREAKBREAKBREAKBREAKBREAKBREAKBREAKBREAKBREAK

Recip Combustion ProcessNormal CombustionThree Necessary Elements Fuel (to regulate engine speed and load)Air (in the proper ratio to fuel for complete combustion)Ignition (at the proper time to produce power efficiently within engine design pressure limits)

Recip Combustion ProcessAbnormal Combustion and some CausesMisfiring (late partial or no burning)Weak IgnitionMixture Too Lean Inconsistent MixingDetonation (rapid burning)Mixture Too RichFuel QualityIgnition Timing Advanced Too Far

Recip Combustion ProcessAbnormal Combustion (continued)Pre-ignition (premature burning)Hot Spots in the Combustion ChamberIgnition Timing Extremely Advanced

Pre-IgnitionNormal CombustionMisfire

Recip Combustion ControlsGovernors Air/Fuel RatioIgnition Timing

GovernorsGeneral DescriptionThe Governor monitors and controls engine speed and/or load by regulating the fuel delivered to the engine power cylinders.

The fuel delivered is changed by the controller output signal to a fuel gas or fuel oil actuator. On Dual Fuel engines, thisoutput controls both fuel gas and fuel oil, either through mechanical linkage or by separate outputs to two actuators.

Governors may be simple speed controls or may also include Droop and Isochronous Load Sharing controls.

Speed and Load Control (Governing)CI EnginesUnit injector enginesMechanical actuator on common fuel rackUnit pump enginesActuator on common fuel rackInjection duration control (EDIS)Jerk pump enginesActuator on volume control lever All systems use engine speed sensors

Speed and Load Control (Governing)SI EnginesCarbureted (homogeneous charge) enginesActuator on throttle valve (controlling air flow only)Port injected engines (single point and multi-port)Duration of injection controlDirect injected (stratified charge) enginesActuator on fuel manifold pressure control valveDuration control of gas admission valvesAll systems use engine speed sensors

PG/PLGas Valve

FuelGasPiping

Air/Fuel Ratio DefinitionThe mass of air flow divided by the mass of fuel flow consumed by the engine (sometimes we cheat). TypesHydraulicPneumaticDigital ElectricSystemSpeed/ Load SensorsControllerActuator/ Linkage/ Valve

Air/Fuel RatioWhy is Air/Fuel Ratio Important ?Primary factor in emissions formationImproves engine efficiencyHas a strong effect on cylinder component temperature (valves, heads, plugs, etc.) Affects pre-turbine exhaust temperatureStrong effect on detonation and misfire.

Air/Fuel RatioGeneral DescriptionThe Air/Fuel Ratio controller monitors engine speed and loadinputs and regulates the intake air manifold pressure.

The Air/Fuel Ratio is changed by the controller output signal to a control valve. This valve increases or decreases air manifold pressure by partially bypassing exhaust gas around a turbocharger, dumping air at the turbocharger air discharge or throttling the intake air or by adjusting fuel gas pressure.

Optimum Air/Fuel Ratio settings produce the lowest fuelconsumption or the lowest emissions parameter.

Exhaust BypassValve TurbochargerAirInletPipeExhaustDischargePiping

BlowerInlet Air ButterflyValve and ActuatorAir Intake Piping

Air/Fuel RatioStoichiometric Air/Fuel RatioThe chemically correct amounts of air and fuel such that all of the oxygen in the air and the fuel are consumed after combustionNatural Gas (Methane) stoichiometric AFR=17.1 to 1LAMBDA(l) is the ratio of the actual AFR to the theoretical stoichiometric AFRAt 17.1 to 1 stoichiometric AFR... l = 1.0Exhaust O2 percentage rises with AFR

Air/Fuel RatioCH4 + 2O2 >> CO2 + 2H2OMETHANEFROM AIRCOCH4NONO2N2{WASTE PRODUCTSINTAKEEXHAUST

Air/Fuel RatioStoichiometric Air/Fuel Ratio Commonly called Rich-BurnIf proper combustion takes place, there is no Oxygen left in the exhaustRuns near to Stoichiometric, but at Stoich NOX, CO and HC are highA 3-way CAT can eliminate most pollutantsCATs are very efficient, but only at Stoich

NOXHCCOCOHCHow Air/Fuel Ratio Affects EmissionsAir Fuel Ratio1517192123252729

Air/Fuel RatioLean-Burn Air/Fuel RatioStudies found that when combustion temperatures are decreased, NO and NO2 production is decreased.By adding extra air, the temperature can be reduced, thereby decreasing NOX levels.However, too much air can cause problems igniting the mixture, so high energy (torch) ignition systems are required.

1517192123252729NOXHCCOCOHCHOW AFR AFFECTS EMISSIONSAir/Fuel RatioLEAN-BURNOPERATING WINDOW

Air/Fuel RatioLean-Burn Air/Fuel RatioSuccessful running with a AFR of 27 to 30exhibits a significant reduction in NOXSlower flame speed of lean mixture requires a higher energy ignition systemFurther leaning out will reduce NOX at a lesser rateIf the AFR is too lean the mixture reaches the misfire limit.

14161820222426Required Ignition Energy vs. AFRAir/Fuel RatioIgnition Energy28

Ignition TimingTypesPneumaticDigital ElectricSystemSpeed/ Load SensorsControllerActuator/ Timer

Ignition TimingEffects of Ignition TimingFuel Savings by controlling Ignition TimingExhaust temps increase by retarding timing which can increase air manifold pressure and save turbo assist air by increasing turbo speedAs manifold temp or fuel heating value increases, retarding the timing reduces the chances of detonation

Ignition Timing - SparkGeneral Description The Ignition Timing controller monitors engine parameters and tells the Ignition timer where, in the combustion cycle, to fire the spark plug.

The ignition timing is changed by the controller output signal to an electronic timer or to a mechanical actuator that physically rotates the timer.

Engine testing establishes the ignition timing schedule and which parameters are monitored by the controller .

GovernorIgnitionGovernor

Fuel Injection Timing - DieselGeneral DescriptionThe Ignition Timing of diesel engines is commonly called Fuel Injection Timing and is generally not variable. The Mechanical design of the camshaft, fuel injection pumps and fuel injectors and their installation settings determine diesel fuel injection timing.

Some fuel injection pumps are built with variable timing linkage for external fuel injection timing control. These injector types are beneficial with alternate fuel types.

Reciprocating Engines OverviewQuestion & Answer period

Thank you for your attendance!!!

2-Cycle IntegralEngine Compressor

1517192123252729Exhaust Oxygen Concentration vs. Air Fuel RatioAir Fuel RatioOxygen Concentration

1517192123252729NOXHCCOCOHCHOW AFR AFFECTS CAT EFFICIENCYAir Fuel RatioNOXNARROW OPERATING AFRWINDOW FOR A 3-WAY CATCATALYTIC CONVERTER EFFICIENCY

AIR/FUEL RATIO3-WAY CATALYTIC CONVERTERREDUCES NOX2CO + 2NO >> 2CO2 + N2OXIDIZES HYDROCARBONS(HC)CH4 + 2O2 >> CO2 + 2H2OOXIDIZES CARBON MONOXIDE(CO)2CO + O2 >> 2CO2

1012141618202325How Temperature Varies With AFRAir Fuel RatioCombustion Temperatures

14161820222426Flame Speed vs. AFRAir/Fuel RatioFlame Speed

Sheet1

Data Log For ANR Storage Caterpillar 3516 Gas Generator Set

Date Tested: 20 Jan 96

Pre IGEM (Air/Fuel Ratio)

Set 1Set 2Set 3Set 4Set 5Set 6Set 7Set 8Set 9Set 10Set 11Set 12Set 13Set 14

KW98152200244300338390443504554596642700750

O2%1.62.64.14.95.56.26.77.18.18.89.19.299.2

NO ppm19653147363534843088260921361675750408217155201150

NO2 ppm331282443072962412011651139177687463

NOx ppm19983275387937913384285023371840863499294223275213

Fuel Flow287032823690406245005010546060606780750080408820936010200

Post IGEM (Air/Fuel Ratio)

Set 1Set 2Set 3Set 4Set 5Set 6Set 7Set 8Set 9Set 10Set 11Set 12Set 13Set 14

KW98153200243285333391439498551594643700750

O2%8.18.89.39.58.69.19.71010109.89.59.59.5

NO ppm71262147140442156854747505510196108

NO2 ppm1663535483585142424344575652

NOx ppm8732520019452521413689899399158152160

Fuel Flow264032403720420045005040588065407260792087008940969810680

% Difference in Pre and Post IGEM (Air/Fuel Ratio)

Set 1Set 2Set 3Set 4Set 5Set 6Set 7Set 8Set 9Set 10Set 11Set 12Set 13Set 14

KW0%0%0%0%0%0%0%0%0%0%0%0%0%0%

O2406%238%127%94%56%47%45%41%23%14%8%3%6%3%

NO-96%-92%-96%-96%-86%-94%-96%-97%-94%-88%-75%-35%-52%-28%

NO2-52%-51%-78%-82%-72%-76%-75%-75%-63%-53%-43%-16%-24%-17%

NOx-96%-90%-95%-95%-84%-92%-94%-95%-90%-81%-66%-29%-45%-25%

Fuel Flow-8%-1%1%3%0%1%8%8%7%6%8%1%4%5%

c:\msoffice\excel\apps\igem\tstrslts.xls john felts

Chart1

1.68.1199887

2.68.83275325

4.19.33879200

4.99.53791194

5.58.63384525

6.29.12850214

6.79.72337136

7.110184089

8.11086389

8.81049993

9.19.829499

9.29.5223158

99.5275152

9.29.5213160

O2 FloTech Open

O2 IGEM Control

NOx FloTech Open

NOx IGEM Control

Engine Load, kW

Exhaust Oxygen, %

NOx, ppm

Exhaust Oxygen Percentage and NOx ConcentrationPre and Post IGEM

Chart1 (2)

1.61998

2.63275

4.13879

4.93791

5.53384

6.22850

6.72337

7.11840

8.1863

8.8499

9.1294

9.2223

9275

9.2213

O2 FloTech Open

NOx FloTech Open

Engine Load, kW

Exhaust Oxygen, %

NOx, ppm

Exhaust Oxygen Percentage and NOx ConcentrationPre IGEM

Chart1 (3)

8.187

8.8325

9.3200

9.5194

8.6525

9.1214

9.7136

1089

1089

1093

9.899

9.5158

9.5152

9.5160

O2 IGEM Control

NOx IGEM Control

Engine Load, kW

Exhaust Oxygen, %

NOx, ppm

Exhaust Oxygen Percentage and NOx Concentrationwith IGEM

40 20 TDC20 40 60 80 IGNITION AND ITS AFFECTSBTDCATDCCRANK ANGLECylinder PressureStart of Ignition