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Emission ControlsEmission Controls

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emission control systememission control system Purpose: control emissions and exhaust from vehicle Purpose: control emissions and exhaust from vehicle Turn the harmful gases the car manufactures into Turn the harmful gases the car manufactures into

harmless ones that don't ruin the environmentharmless ones that don't ruin the environment Problem gases : Problem gases :

– hydrocarbons (unburned) hydrocarbons (unburned) HCHC– carbon monoxide carbon monoxide COCO– nitrogen oxides nitrogen oxides NOxNOx– sulfur dioxide sulfur dioxide SO2SO2– phosphorus phosphorus PP– lead and other metals lead and other metals PbPb

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Three (major) PollutantsThree (major) Pollutants

– Hydrocarbons (HC)Hydrocarbons (HC)

» Un-burnt GasolineUn-burnt Gasoline

– Carbon MonoxideCarbon Monoxide (CO)(CO)

» CO results from the incomplete combustion FuelCO results from the incomplete combustion Fuel

– Oxides of Nitrogen (NOx)Oxides of Nitrogen (NOx)

» NOx results from air being overheated.NOx results from air being overheated.

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HCHC

HC results from gasoline that is not burned HC results from gasoline that is not burned in the engine. This can be due from in the engine. This can be due from misfires, burning rich, open loop operation, misfires, burning rich, open loop operation, or excessive cranking.or excessive cranking.

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COCOCOCO results from the incomplete combustion results from the incomplete combustion

of organic materials.of organic materials.

gasoline, kerosene, natural gas, propane, gasoline, kerosene, natural gas, propane, coal, wood, charcoal, diesel fuel, heating coal, wood, charcoal, diesel fuel, heating oil and almost any other combustible oil and almost any other combustible material, such as tobacco and paper. material, such as tobacco and paper.

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NOxNOx Nitrogen oxides (NOx) are reactive gasesNitrogen oxides (NOx) are reactive gases Cause a host of environmental concerns impacting adversely on Cause a host of environmental concerns impacting adversely on

human health and welfare. human health and welfare. Nitrogen dioxide (NO2), in particular, is a brownish gas that has Nitrogen dioxide (NO2), in particular, is a brownish gas that has

been linked with higher susceptibility to respiratory infection, been linked with higher susceptibility to respiratory infection, increased airway resistance in asthmatics, and decreased pulmonary increased airway resistance in asthmatics, and decreased pulmonary function.function.

Other effects:Other effects: Principle cause of ground-level ozone formation Principle cause of ground-level ozone formation Contribute to acid deposition, which can damage trees at high Contribute to acid deposition, which can damage trees at high

elevations and increases the acidity of lakes and streams, which can elevations and increases the acidity of lakes and streams, which can severely damage aquatic life severely damage aquatic life

Contribute to increased levels of particulate matter by changing into Contribute to increased levels of particulate matter by changing into nitric acid in the atmosphere and forming particulate nitrate nitric acid in the atmosphere and forming particulate nitrate

combustion temperature gets above 2,500 degrees combustion temperature gets above 2,500 degrees F F

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Evaporation from the fuel tank. 5%Evaporation from the fuel tank. 5% Blow-by gases which escape from the crankcase. Blow-by gases which escape from the crankcase.

20-25%20-25% Tail pipe emissions. 60-75%Tail pipe emissions. 60-75% Carburetor evaporation from the float bowl on old Carburetor evaporation from the float bowl on old

cars.cars.

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POLUTIONPOLUTION

20 % Crankcase 20 % Crankcase vaporsvapors

20% Fuel 20% Fuel VaporizationVaporization

60% Exhaust60% Exhaust

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Three Ways to Control PollutionThree Ways to Control Pollution

1 1 – Improve combustion– Improve combustion 2 – Capture the vapors and re-burn them.2 – Capture the vapors and re-burn them. 3 – Treat the exhaust.3 – Treat the exhaust.

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Ways to Combat PollutionWays to Combat Pollution

Capture the vapors and burn themCapture the vapors and burn them– EGREGR– Charcoal CanisterCharcoal Canister

Improve the combustionImprove the combustion– Monitor mixtureMonitor mixture– Less PowerLess Power

Treat the exhaustTreat the exhaust– Fewer EmissionFewer Emission

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WHY 14.7:1WHY 14.7:1

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Road Draft Tubes Road Draft Tubes

Pre-PCVPre-PCV Crankcase vapors vented Crankcase vapors vented

into atmosphereinto atmosphere

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Vapor Recovery Type SystemsVapor Recovery Type Systems

Positive Crankcase Ventilation (PCV)Positive Crankcase Ventilation (PCV) Fuel Tank Vapor Recovery (VVR)Fuel Tank Vapor Recovery (VVR)

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Positive Crankcase VentilationPositive Crankcase Ventilation Uses manifold Uses manifold

vacuum to clean vacuum to clean blow-by gases blow-by gases from crankcase.from crankcase.

Needs a breather Needs a breather tube for fresh air.tube for fresh air.

Needs a PCV Needs a PCV valve to regulate valve to regulate the amount of the amount of gases entering gases entering the intake the intake manifold.manifold.

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PCV OperationPCV Operation

The PCV valve has The PCV valve has two functions:two functions:

1. To regulate the 1. To regulate the amount of vapor amount of vapor entering the intake entering the intake manifold at various manifold at various engine speeds.engine speeds. 2. Prevent damage 2. Prevent damage from backfire.from backfire.

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Regulating the PCV Vapor Regulating the PCV Vapor FlowFlow

AmountAmount

ConditionCondition

ManifoldManifold

VacuumVacuum

Blow-byBlow-by

GasesGases

IdleIdle HighHigh

VacuumVacuum

Small Small

VolumeVolume

High SpeedHigh Speed Low VacuumLow Vacuum Large Large

VolumeVolume

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PCV ServicePCV Service Replace PCV valve every 3 years/30,000 miles. Replace PCV valve every 3 years/30,000 miles. Clean the breather filter if applicable. The valve Clean the breather filter if applicable. The valve

can be cleaned also if you don’t want to replace it.can be cleaned also if you don’t want to replace it. Inspect hoses for proper routing and deterioration.Inspect hoses for proper routing and deterioration. Check the air cleaner housing for oil build up.Check the air cleaner housing for oil build up. Check PCV system function.Check PCV system function. 1) Use the PCV vacuum tester.1) Use the PCV vacuum tester.

2) Use the tachometer and look for RPM 2) Use the tachometer and look for RPM drop.drop.

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PCV Trouble-Shooting NotesPCV Trouble-Shooting Notes

Defective PCV system can cause big time Defective PCV system can cause big time vacuum leaks. This can lead to a very fast vacuum leaks. This can lead to a very fast idle speed or stalling.idle speed or stalling.

If the valve or hoses get clogged the vapors If the valve or hoses get clogged the vapors back-up into the air cleaner clogging it too back-up into the air cleaner clogging it too and puts oil in the air cleaner housing.and puts oil in the air cleaner housing.

A strange problem is if a valve cover gasket A strange problem is if a valve cover gasket starts leaking oil winds up in the air cleaner starts leaking oil winds up in the air cleaner also.also.

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Fuel Tank Vapor RecoveryFuel Tank Vapor Recovery

Does not allow gasoline Does not allow gasoline to evaporate from the to evaporate from the gas tank to the gas tank to the atmosphere.atmosphere.

Gas tank is sealed and Gas tank is sealed and vapors travel to a vapors travel to a charcoal canister.charcoal canister.

The canister is purged of The canister is purged of vapors by the intake vapors by the intake manifold and burned in manifold and burned in the engine.the engine.

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Older Style EvapOlder Style Evap

1) Fresh air enters here

3) Fresh enters here mixes w/fuel vapor

2) Fuel vapor moves to canister

4) Intake vacuum draws vapor to manifold

5) PCM controls flow to manifold

6) Vapor burns in cylinders

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OBDII Evap 1OBDII Evap 1

Fresh air vent controlled by the PCM.Closed when engine is off.Open while engine is running.

Vapor managementvalve.Closed when engine is off.Pulsed when engineis running.

PCM monitorspressure in fueltank. Can causeDTC.

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Heated Air Intake SystemsHeated Air Intake Systems

Warms-up inlet Warms-up inlet air around air around exhaust manifold.exhaust manifold.

Enhances fuel Enhances fuel evaporation for evaporation for better better combustion.combustion.

Maintains a Maintains a 120120˚F air temp.˚F air temp.

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Heated air intakeHeated air intake

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Heated IntakeHeated Intake Helps Helps vaporizevaporize gasolinegasoline in a cold engine. in a cold engine. TThermostathermostat in the air cleaner horn is connected to in the air cleaner horn is connected to

the outside of the the outside of the exhaust manifoldexhaust manifold. . engine is cold, the engine is cold, the thermostatthermostat closes a damper in closes a damper in

the air cleaner horn the air cleaner horn air going to the carburetor does not come through air going to the carburetor does not come through

the open end of the horn. the open end of the horn. Instead the air comes from above the hot exhaust Instead the air comes from above the hot exhaust

manifold. manifold. Engine warms up, the thermostat opens the Engine warms up, the thermostat opens the

damper air is taken in from the end of the horn. damper air is taken in from the end of the horn.

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Early Fuel Evaporation (EFE)Early Fuel Evaporation (EFE)

Helps engine warm-up faster.Helps engine warm-up faster. Uses exhaust gas to warm intake Uses exhaust gas to warm intake

manifold.manifold. Uses a special passageway under the Uses a special passageway under the

intake manifold called a intake manifold called a crossovercrossover.. Use mostly on carbureted and Use mostly on carbureted and

throttle body Vee engines.throttle body Vee engines. A control valve forces the exhaust A control valve forces the exhaust

gas from one bank to the other.gas from one bank to the other. Only operates during the first 5 Only operates during the first 5

minutes or so of operationminutes or so of operation..

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heat crossoverheat crossover:: A passage from one exhaust manifold up, A passage from one exhaust manifold up,

over, and under the carburetor and on to over, and under the carburetor and on to the other manifold. Usually found on V-8 the other manifold. Usually found on V-8 or V-6 engines. This crossover provides or V-6 engines. This crossover provides heat to the carburetor during engine heat to the carburetor during engine warmup. warmup.

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Heat Riser (EFE)Heat Riser (EFE) An area, An area, surrounding a surrounding a portion of the portion of the intake manifoldintake manifold, , through which through which exhaust gasesexhaust gases can pass to heat can pass to heat the fuel mixture the fuel mixture during warmup. during warmup.

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heat-control valveheat-control valve:: Controlled by temperature Controlled by temperature

changes. changes. ambient temperature is cold ambient temperature is cold

or the engine has not warmed or the engine has not warmed up, closed up, closed

so that some of the hot so that some of the hot exhaust gasesexhaust gases passes by the passes by the intake manifoldintake manifold to pre-heat the to pre-heat the fuel mixture going to the fuel mixture going to the cylinderscylinders. As the engine warms . As the engine warms up, the valve opens up and no up, the valve opens up and no exhaust gases pass by the exhaust gases pass by the intake manifoldintake manifold. .

If valve does not operate If valve does not operate properly, the engine has properly, the engine has difficulty in start up or the fuel difficulty in start up or the fuel may cause may cause vapor lockingvapor locking. .

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Manifold Heat ControlManifold Heat Control improves vaporizationimproves vaporization improves mixture distributionimproves mixture distribution As engine warms up, the thermostatic spring As engine warms up, the thermostatic spring

is heated and loses tensionis heated and loses tension allows counterweight to change position of allows counterweight to change position of

heat control valve gradually so that, at higher heat control valve gradually so that, at higher driving speeds with a thoroughly warmed driving speeds with a thoroughly warmed engine, exhaust gases pass directly to the engine, exhaust gases pass directly to the exhaust pipe and mufflerexhaust pipe and muffler

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Exhaust Gas Recirculation Exhaust Gas Recirculation (EGR)(EGR)

Used to send some of Used to send some of the exhaust gas back the exhaust gas back into the cylinders into the cylinders

Reduce combustion Reduce combustion temperaturestemperatures

Reduces NOx gasesReduces NOx gases

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AIR INJECTION SYSTEMSAIR INJECTION SYSTEMS Pump airPump air

– Exhaust manifoldExhaust manifold

– Catalytic converterCatalytic converter

Air PumpAir Pump Diverter ValveDiverter Valve One-way ValvesOne-way Valves Air Switching ValveAir Switching Valve Hoses & TubingHoses & Tubing

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Catalytic ConverterCatalytic Converter Contains precious Contains precious

metalsmetals Down Stream O2Down Stream O2 Re-burnerRe-burner 2 way2 way 3 way3 way 3 way w/air3 way w/air

aluminum oxide, aluminum oxide, platinum and platinum and palladium palladium

carbon monoxide and carbon monoxide and hydrocarbons to hydrocarbons to change into water change into water vapor and carbon vapor and carbon dioxide dioxide

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2 way2 way Two Way CatalystTwo Way Catalyst: : oxidize CO and HC to oxidize CO and HC to

CO2 and H2O. CO2 and H2O. Temperature of 200°C for Temperature of 200°C for

catalyst to "light off". catalyst to "light off". Above 450°C, oxidation Above 450°C, oxidation

of SO2 to SO3 occurs, of SO2 to SO3 occurs, combines with water to combines with water to form sulfuric acid. form sulfuric acid.

Leads to the formation of Leads to the formation of sulfates. (acid rain)sulfates. (acid rain)

2-way catalyst may reduce 2-way catalyst may reduce NOx by 10-20 %. NOx by 10-20 %.

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3 way3 way Reactions between CO, HC, and NOx result in the Reactions between CO, HC, and NOx result in the

removal of all three major exhaust pollutants. removal of all three major exhaust pollutants. In order to get high conversions of CO and NOx, the In order to get high conversions of CO and NOx, the

air-to-fuel mixture should be held close to the air-to-fuel mixture should be held close to the stoichiometric requirement. stoichiometric requirement.

If not, conversion of either NOx or CO will deteriorate. If not, conversion of either NOx or CO will deteriorate. Requires monitoring the oxygen in the exhaust gas and Requires monitoring the oxygen in the exhaust gas and

using it in a feedback loop to adjust the fuel to air ratio. using it in a feedback loop to adjust the fuel to air ratio. Makes the 3-way closed loop system more expensive Makes the 3-way closed loop system more expensive

than an open loop 2-way, or an open loop 3-way than an open loop 2-way, or an open loop 3-way system. system.

Some latest catalysts have a NOx reduction of 70-75%.Some latest catalysts have a NOx reduction of 70-75%.

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3 way with air3 way with air

Uses air tube after Rhodium sub straightUses air tube after Rhodium sub straight Air helps reduce HC & COAir helps reduce HC & CO

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Test Exhaust EmissionsTest Exhaust Emissions

Shop tests: The exhaust is sampled and Shop tests: The exhaust is sampled and checked for the following gases.checked for the following gases.– 1 – Hydrocarbons (HC)1 – Hydrocarbons (HC)– 2 - Carbon Monoxide (CO)2 - Carbon Monoxide (CO)– 3 – Carbon Dioxide (CO2)3 – Carbon Dioxide (CO2)– 4 – Oxygen (O2)4 – Oxygen (O2)

State Emission Testing: Vehicle run on a State Emission Testing: Vehicle run on a dynamometer (IM240 Test) Measures HC, dynamometer (IM240 Test) Measures HC, CO, CO2, O2CO, CO2, O2

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Oxygen SensorsOxygen Sensors

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BAD O2 BAD O2 sensorssensors

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Enhanced Evap. System OPEnhanced Evap. System OP

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EPA EMISSION EPA EMISSION STANDARDSSTANDARDS

1968-19711968-1971 HC 900 ppmHC 900 ppm CO 9.0%CO 9.0% 1972-19741972-1974 HC 800 ppmHC 800 ppm CO 8.0%CO 8.0% 1975-19791975-1979 HC 700 ppmHC 700 ppm CO 7.0%CO 7.0% 19801980 HC 300 ppmHC 300 ppm CO 3.0%CO 3.0% 1981- on1981- on HC 220 ppmHC 220 ppm CO 1.2%CO 1.2% I.M. 240 TestI.M. 240 Test

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IM 240IM 240 replaced the idle test replaced the idle test measures emissions as the vehicle is driven measures emissions as the vehicle is driven

on a dynamometer on a dynamometer taking up to four minutes taking up to four minutes simulates actual urban drivingsimulates actual urban driving consists of various accelerations, consists of various accelerations,

decelerations and cruise speeds up to 57 decelerations and cruise speeds up to 57 miles per hourmiles per hour

pass/fail standards are more lenient for pass/fail standards are more lenient for older vehicles older vehicles

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OBD2 TestingOBD2 Testing

Uses a scan toolUses a scan tool Plug in and goPlug in and go Check for codesCheck for codes Check sensor operationCheck sensor operation Gas capGas cap Cayt in place w/ mirrorCayt in place w/ mirror

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OBD IIIOBD III

Cell/Satellites?Cell/Satellites?

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GOOD NEWSGOOD NEWS

Emission controls have reduced carbon Emission controls have reduced carbon monoxide and hydrocarbon emissions by monoxide and hydrocarbon emissions by about ninety-six percent from pre-control about ninety-six percent from pre-control vehicles. vehicles.

That's almost a hundred percent! That's almost a hundred percent!

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Exhaust PipeExhaust Pipe The exhaust pipe is the bent-up or convoluted The exhaust pipe is the bent-up or convoluted

pipes you will notice underneath your car. pipes you will notice underneath your car. Some are shaped to go over the rear axle, Some are shaped to go over the rear axle,

allowing the rear axle to move up and down allowing the rear axle to move up and down without bumping into the exhaust pipe; without bumping into the exhaust pipe;

some are shaped to bend around under the floor some are shaped to bend around under the floor of the car, connecting the catalytic converter of the car, connecting the catalytic converter with the muffler. with the muffler.

Exhaust pipes are usually made out of stainless Exhaust pipes are usually made out of stainless steel, since the high heat conditions involved steel, since the high heat conditions involved with the muffler system will cause rustwith the muffler system will cause rust

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Reverse-flow MufflerReverse-flow Muffler

The reverse-flow muffler is oval-shaped and The reverse-flow muffler is oval-shaped and has multiple pipes. has multiple pipes.

Four chambers and a double jacket are used Four chambers and a double jacket are used to accomplish muffling of the exhaust noise. to accomplish muffling of the exhaust noise.

Exhaust gases are directed to the third Exhaust gases are directed to the third chamber, forced forward to the first chamber, chamber, forced forward to the first chamber, from where they travel the length of the from where they travel the length of the muffler and are exhausted into the tail pipe. muffler and are exhausted into the tail pipe.

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Straight Through MufflerStraight Through Muffler

The straight through muffler has a central tube, The straight through muffler has a central tube, perforated with several openings which lead into an outside chamber perforated with several openings which lead into an outside chamber

packed with a sound absorbing (or insulating) material. packed with a sound absorbing (or insulating) material. As the exhaust gases expand from the perforated inner pipe into the As the exhaust gases expand from the perforated inner pipe into the

outer chamber, they come in contact with the insulator and escape to outer chamber, they come in contact with the insulator and escape to the atmosphere under constant pressure. the atmosphere under constant pressure.

Because of this, the expanding chamber tends to equalize or spread Because of this, the expanding chamber tends to equalize or spread the pressure peaks throughout the exhaust from each individual the pressure peaks throughout the exhaust from each individual cylinder of the engine. cylinder of the engine.

A V-8 engine requires two exhaust manifolds and either one or two A V-8 engine requires two exhaust manifolds and either one or two mufflers and often accompanying resonators. mufflers and often accompanying resonators.

If one muffler is used, the exhaust pipe from one manifold meets the If one muffler is used, the exhaust pipe from one manifold meets the other one in the form of a "Y". other one in the form of a "Y".

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Dual Exhaust SystemDual Exhaust System

The advantage of a dual exhaust system is that the engine The advantage of a dual exhaust system is that the engine exhausts more freely, exhausts more freely,

thereby lowering the back pressure which is inherent in an thereby lowering the back pressure which is inherent in an exhaust system. exhaust system.

With a dual exhaust system, a sizable increase in engine With a dual exhaust system, a sizable increase in engine horsepower can be obtained horsepower can be obtained

because the "breathing" capacity of the engine is because the "breathing" capacity of the engine is improved, improved,

leaving less exhaust gases in the engine at the end of each leaving less exhaust gases in the engine at the end of each exhaust stroke. exhaust stroke.

This, in turn, leaves more room for an extra intake of the This, in turn, leaves more room for an extra intake of the air-fuel mixture. air-fuel mixture.