gasoline electronic fuel injection systems

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Gasoline electronic Direct Gasoline electronic Direct Injection System Injection System prepared by: prepared by: مد ح م مد ح م لاح ص لام س ا مد ح م مد ح م لاح ص لام س ا ان ض م د ر ي س ل ى ا ط عا م ل وا ب! د ا ي س ل ا ان ض م د ر ي س ل ى ا ط عا م ل وا ب! د ا ي س ل ا لام سلا ا ف ي س ;pma&مد ح! م ا لا س ا لام سلا ا ف ي س ;pma&مد ح! م ا لا س ا ه ف ي ل خ مد ح! مد ا ح م لام س ا ه ف ي ل خ مد ح! مد ا ح م لام س ا د ي س ل مد ا ح! رى ا س ي مد ح! ا د ي س ل مد ا ح! رى ا س ي مد ح! ا د0 ي ج م ل دا ي ع ى ن و ع لام س ا د0 ي ج م ل دا ي ع ى ن و ع لام س ا رى;pma& ه و ج ل ود ا م ح م مد ح م ى ف صط م رى;pma& ه و ج ل ود ا م ح م مد ح م ى ف صط م

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Page 1: Gasoline electronic  fuel injection systems

Gasoline electronic Direct Injection Gasoline electronic Direct Injection SystemSystem prepared by:prepared by:

محمد • محمد صالح محمد اسالم محمد صالح اسالمرمضان • السيد أبوالمعاطى رمضان السيد السيد أبوالمعاطى السيداالسالم • سيف أحمد االسالم اسالم سيف أحمد اسالمخليفه • أحمد محمد خليفه اسالم أحمد محمد اسالمالسيد • أحمد يسرى السيد أحمد أحمد يسرى أحمدعبدالمجيد • عونى عبدالمجيد اسالم عونى اسالمالجوهرى • محمود محمد الجوهرى مصطفى محمود محمد مصطفى

Page 2: Gasoline electronic  fuel injection systems

Gasoline electronic Fuel Gasoline electronic Fuel Injection SystemsInjection Systems

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IntroductionIntroductionA modern gasoline injection system uses A modern gasoline injection system uses

pressurepressure from an electric fuel pump to from an electric fuel pump to spray fuel into the enginespray fuel into the engine intake manifold. intake manifold. Like a carburetor, it must provide theLike a carburetor, it must provide the engine with the correct air-fuel mixture for engine with the correct air-fuel mixture for specificspecific operating conditions.    Unlike a operating conditions.    Unlike a carburetor, howevercarburetor, however, , PRESSURE, not PRESSURE, not engine vacuum, is used to feed fuelengine vacuum, is used to feed fuel into into the enginethe engine. . This  makes  the  gasoline This  makes  the  gasoline  injection injection system  very  efficientsystem  very  efficient

Page 4: Gasoline electronic  fuel injection systems

A gasoline injection system has several A gasoline injection system has several possible advantages over a possible advantages over a carburetor type of fuel system.  carburetor type of fuel system.  

Some advantages  are  as  followsSome advantages  are  as  follows::* Improved atomization. Fuel is forced into * Improved atomization. Fuel is forced into

the intake manifold under pressure that the intake manifold under pressure that helps break fuel droplets into a fine mist. helps break fuel droplets into a fine mist.

* Better fuel distribution. Equal flow of fuel * Better fuel distribution. Equal flow of fuel vapors  into  each  cylinder.vapors  into  each  cylinder.

* Smoother idle. Lean fuel mixture can be * Smoother idle. Lean fuel mixture can be used without rough idle because of better used without rough idle because of better fuel distribution and  low-speed fuel distribution and  low-speed  atomization. atomization.

Page 5: Gasoline electronic  fuel injection systems

* Lower  emissions.  Lean  efficient  air-fuel * Lower  emissions.  Lean  efficient  air-fuel  mixture reduces exhaust pollution. mixture reduces exhaust pollution.

* Better  cold  weather  drivability.  Injection * Better  cold  weather  drivability.  Injection provides better control of mixture enrichment provides better control of mixture enrichment than a carburetor.than a carburetor.

* Increased  engine  power.  Precise  metering * Increased  engine  power.  Precise  metering  of fuel to each cylinder and increased air flow  of fuel to each cylinder and increased air flow can result in more horsepower output. can result in more horsepower output.

* Fewer parts. Simpler, late model, electronic * Fewer parts. Simpler, late model, electronic fuel injection  system  have  fewer  parts  than fuel injection  system  have  fewer  parts  than  modern computer-controlled  carburetors.  modern computer-controlled  carburetors.

Page 6: Gasoline electronic  fuel injection systems

There are many types of gasoline There are many types of gasoline injection systems. Before studying injection systems. Before studying the most common ones, you should the most common ones, you should havehave ::

A basic knowledge of the different classificationsA basic knowledge of the different classifications :: * * single- or multi-point injectionsingle- or multi-point injection * indirect or direct injection* indirect or direct injection

Page 7: Gasoline electronic  fuel injection systems

• The point or location of fuel injection is one way The point or location of fuel injection is one way to classify a gasoline injection system. A single-to classify a gasoline injection system. A single-point injection  system,  also  call  throttle  body point injection  system,  also  call  throttle  body  injection  (TBI), has the injector nozzles in a  injection  (TBI), has the injector nozzles in a throttle body assembly on top of the engine. throttle body assembly on top of the engine. Fuel is sprayed into the top center of the  intake Fuel is sprayed into the top center of the  intake  manifold manifold . .

Page 8: Gasoline electronic  fuel injection systems

• A multi-point  injection  system,  also  called A multi-point  injection  system,  also  called  port injection, has an injector in the port (air- port injection, has an injector in the port (air-fuel passage) going to each cylinder. Gasoline fuel passage) going to each cylinder. Gasoline is sprayed into each intake port and toward is sprayed into each intake port and toward each intake valve. Thereby, the term each intake valve. Thereby, the term  multipoint (more  than  one  location) fuel  multipoint (more  than  one  location) fuel  injection is used. injection is used.

Page 9: Gasoline electronic  fuel injection systems

• An indirect injection system An indirect injection system sprays fuel into the engine  intake  manifold. sprays fuel into the engine  intake  manifold.   Most  gasoline  injection   Most  gasoline  injection systems are of this type. systems are of this type.

• Direct injection forces fuel Direct injection forces fuel into the engine combustion into the engine combustion chambers. Diesel injection chambers. Diesel injection systems are direct type.systems are direct type.

SoSo Gasoline electronic Direct Injection System Gasoline electronic Direct Injection System

is Classified asis Classified as : : multi-point and Direct injection multi-point and Direct injection

systemssystems

Page 10: Gasoline electronic  fuel injection systems
Page 11: Gasoline electronic  fuel injection systems

System componentSystem component ::• Fuel tankFuel tank• Electric fuel pumpElectric fuel pump• Fuel filterFuel filter• Electronic control unitElectronic control unit• Common rail and Common rail and Pressure sensor• ElectronicElectronic Injectors• fuel line

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Fuel tankFuel tank• is safe container for flammable liquids and is safe container for flammable liquids and

typically part of an engine system in which typically part of an engine system in which the fuel is stored and propelled (fuel pump) the fuel is stored and propelled (fuel pump) or released (pressurized gas) into an engine.or released (pressurized gas) into an engine.

• Typically, a fuel tank must allow or provide Typically, a fuel tank must allow or provide the following:the following:

* Safe (UL Approved) fuel storage, there is * Safe (UL Approved) fuel storage, there is some concern that UL (Underwriters some concern that UL (Underwriters Laboratories) is not the final arbiter of safety. Laboratories) is not the final arbiter of safety.

* Filling (the fuel tank must be filled in a secure * Filling (the fuel tank must be filled in a secure way) No Sparks.way) No Sparks.

* Storage of fuel (the system must contain a * Storage of fuel (the system must contain a given quantity of fuel and must avoid leakage given quantity of fuel and must avoid leakage and limit evaporative emissions)and limit evaporative emissions)

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* Provide a method for determining level of fuel in * Provide a method for determining level of fuel in tank, Gauging (the remaining quantity of fuel in tank, Gauging (the remaining quantity of fuel in the tank must be measured or evaluated)the tank must be measured or evaluated)

* Venting (if over-pressure is not allowed, the fuel * Venting (if over-pressure is not allowed, the fuel vapors must be managed through valves) vapors must be managed through valves)

* Feeding of the engine (through a pump)* Feeding of the engine (through a pump) * Anticipate potentials for damage and provide * Anticipate potentials for damage and provide

safe survival potential. safe survival potential.

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Electric fuel Electric fuel pumppump• An electric fuel pump is used on engines with fuel An electric fuel pump is used on engines with fuel injection to pump fuel from the tank to the injectors. injection to pump fuel from the tank to the injectors. The pump must deliver the fuel under high pressure The pump must deliver the fuel under high pressure (typically 30 to 85 psi depending on the application) (typically 30 to 85 psi depending on the application) so the injectors can spray the fuel into the engine.so the injectors can spray the fuel into the engine.

• Electric fuel pumps are usually mounted inside the Electric fuel pumps are usually mounted inside the fuel tank,fuel tank,

• Some vehicles may even have two fuel pumps (a Some vehicles may even have two fuel pumps (a transfer pump inside the tank, and a main fuel transfer pump inside the tank, and a main fuel pump outside). pump outside).

Page 15: Gasoline electronic  fuel injection systems

• Electric fuel pumps come in a variety of Electric fuel pumps come in a variety of designs. Some older applications use a positive designs. Some older applications use a positive displacement "roller cell" pump. This type uses displacement "roller cell" pump. This type uses rollers mounted on an offset disc that rotates rollers mounted on an offset disc that rotates inside a steel ring. Fuel is drawn into the spaces inside a steel ring. Fuel is drawn into the spaces (cells) between the rollers and pushed along (cells) between the rollers and pushed along from the pump inlet to the outlet. This type of from the pump inlet to the outlet. This type of pump can generate very high pressure, and the pump can generate very high pressure, and the flow rate tends to be constant. But the output flow rate tends to be constant. But the output comes in pulses, so a muffler is often mounted comes in pulses, so a muffler is often mounted in the fuel line after the pump to dampen in the fuel line after the pump to dampen pressure pulses. A roller cell pump may also be pressure pulses. A roller cell pump may also be mounted outside the fuel tank, and used with a mounted outside the fuel tank, and used with a second low pressure supply pump mounted second low pressure supply pump mounted inside the fuel tank. inside the fuel tank.

Page 16: Gasoline electronic  fuel injection systems

• Most newer vehicles use a "turbine" style fuel Most newer vehicles use a "turbine" style fuel pump. A turbine pump has an impeller ring pump. A turbine pump has an impeller ring attached to the motor. The blades in the attached to the motor. The blades in the impeller push the fuel through the pump as the impeller push the fuel through the pump as the impeller spins. This type of pump is not a impeller spins. This type of pump is not a positive-displacement pump, so it produces no positive-displacement pump, so it produces no pulsations, runs very smoothly and quietly. It is pulsations, runs very smoothly and quietly. It is also less complicated to manufacture and is also less complicated to manufacture and is very durable. Some aftermarket pump supplies very durable. Some aftermarket pump supplies use this type of pump to replace the older use this type of pump to replace the older designs.designs.

Page 17: Gasoline electronic  fuel injection systems

Fuel filterFuel filter• The fuel filter is the fuel system's primary line The fuel filter is the fuel system's primary line

of defense against dirt, debris and small of defense against dirt, debris and small particles of rust that flake off the inside of the particles of rust that flake off the inside of the fuel tank .fuel tank .

• many filters for fuel injected engines trap many filters for fuel injected engines trap particles as small as 10 to 40 microns in size.particles as small as 10 to 40 microns in size.

• fuel filter normally made into fuel filter normally made into cartridges containing a filter paper. cartridges containing a filter paper.

Page 18: Gasoline electronic  fuel injection systems

Electronic control Electronic control unitunit• In automotive electronics, In automotive electronics, electronic control electronic control

unitunit ( (ECUECU) is a generic term for any embedded ) is a generic term for any embedded system that controls one or more of the electrical system that controls one or more of the electrical systems or subsystems in a motor vehicle.systems or subsystems in a motor vehicle.

• An An engine control unit (ECU)engine control unit (ECU), also known as , also known as power-train control module (PCM)power-train control module (PCM), or , or engine engine control module (ECM)control module (ECM) is a type of electronic is a type of electronic control unit that determines the amount of fuel, control unit that determines the amount of fuel, ignition timing and other parameters an internal ignition timing and other parameters an internal combustion engine needs to keep running. It does combustion engine needs to keep running. It does this by reading values from multidimensional this by reading values from multidimensional maps which contain values calculated by sensor maps which contain values calculated by sensor devices monitoring the engine. devices monitoring the engine.

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Working of Working of ECUECU • Control of fuel injection:Control of fuel injection: ECU will determine ECU will determine

the quantity of fuel to inject based on a number the quantity of fuel to inject based on a number of parameters. If the throttle pedal is pressed of parameters. If the throttle pedal is pressed further down, this will open the throttle body and further down, this will open the throttle body and allow more air to be pulled into the engine. The allow more air to be pulled into the engine. The ECU will inject more fuel according to how much ECU will inject more fuel according to how much air is passing into the engine. If the engine has air is passing into the engine. If the engine has not warmed up yet, more fuel will be injected .not warmed up yet, more fuel will be injected .

• Control of ignition timing : Control of ignition timing : A spark ignition A spark ignition engine requires a spark to initiate combustion in engine requires a spark to initiate combustion in the combustion chamber. An ECU can adjust the the combustion chamber. An ECU can adjust the exact timing of the spark (called ignition timing) exact timing of the spark (called ignition timing) to provide better power and economy.to provide better power and economy.

Page 20: Gasoline electronic  fuel injection systems

• Control of idle speedControl of idle speed : : Most engine systems Most engine systems have idle speed control built into the ECU. The have idle speed control built into the ECU. The engine RPM is monitored by the crankshaft engine RPM is monitored by the crankshaft position sensor which plays a primary role in position sensor which plays a primary role in the engine timing functions for fuel injection, the engine timing functions for fuel injection, spark events, and valve timing. Idle speed is spark events, and valve timing. Idle speed is controlled by a programmable throttle stop or controlled by a programmable throttle stop or an idle air bypass control stepper motor.an idle air bypass control stepper motor.

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Common rail and Common rail and Pressure sensor• The term "common rail" refers to the fact that The term "common rail" refers to the fact that

all of the fuel injectors are supplied by a all of the fuel injectors are supplied by a common fuel rail which is nothing more than a common fuel rail which is nothing more than a pressure accumulator where the fuel is stored pressure accumulator where the fuel is stored at high pressure. This accumulator supplies at high pressure. This accumulator supplies multiple fuel injectors with high pressure fuel.multiple fuel injectors with high pressure fuel.

Page 22: Gasoline electronic  fuel injection systems

• The fuel injectors are typically ECU-The fuel injectors are typically ECU-controlled. When the fuel injectors are controlled. When the fuel injectors are electrically activated a hydraulic valve electrically activated a hydraulic valve (consisting of a nozzle and plunger) is (consisting of a nozzle and plunger) is mechanically or hydraulically opened and mechanically or hydraulically opened and fuel is sprayed into the cylinders at the fuel is sprayed into the cylinders at the desired pressure. Since the fuel pressure desired pressure. Since the fuel pressure energy is stored remotely and the injectors energy is stored remotely and the injectors are electrically actuated the injection are electrically actuated the injection pressure at the start and end of injection is pressure at the start and end of injection is very near the pressure in the accumulator very near the pressure in the accumulator (rail), thus producing a square injection (rail), thus producing a square injection rate. If the accumulator, pump, and rate. If the accumulator, pump, and plumbing are sized properly, the injection plumbing are sized properly, the injection pressure and rate will be the same for each pressure and rate will be the same for each of the multiple injection events.of the multiple injection events.

Page 23: Gasoline electronic  fuel injection systems
Page 24: Gasoline electronic  fuel injection systems

ElectronicElectronic Injectors• The injectors can survive the excessive The injectors can survive the excessive temperature and pressure of combustion by temperature and pressure of combustion by using the fuel that passes through it as a using the fuel that passes through it as a coolant coolant

Page 25: Gasoline electronic  fuel injection systems

• The electronic fuel injector is normally closed, The electronic fuel injector is normally closed, and opens to inject pressurized fuel as long as and opens to inject pressurized fuel as long as electricity is applied to the injector's solenoid electricity is applied to the injector's solenoid coil. coil.

• When the injector is turned on, it opens, spraying When the injector is turned on, it opens, spraying atomized fuel at the combustion chamber .atomized fuel at the combustion chamber .

• Depending on engine operating Depending on engine operating condition ,injection quantity will vary . condition ,injection quantity will vary .

Page 26: Gasoline electronic  fuel injection systems

fuel line• Fuel line hoses carry gasoline from the

tank to the fuel pump, to the fuel filter, and to the fuel injection system. While much of the fuel lines are rigid tube, sections of it are made of rubber hose, which absorb engine and road vibrations.

• There are two basic types of fuel hose: Fuel and oil hoses that meet the SAE 30R7 standard, and fuel injection hose that meets the requirements of SAE 30R9.

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Gasoline direct injectionGasoline direct injection • In internal combustion engines, In internal combustion engines, gasoline gasoline

direct injectiondirect injection is a variant of fuel injection is a variant of fuel injection employed in modern two- and four- stroke employed in modern two- and four- stroke petrol engines. The petrol/gasoline is highly petrol engines. The petrol/gasoline is highly pressurized, and injected via a common rail pressurized, and injected via a common rail fuel line directly into the combustion fuel line directly into the combustion chamber of each cylinder, as opposed to chamber of each cylinder, as opposed to conventional multi-point fuel injection that conventional multi-point fuel injection that happens in the intake tract, or cylinder port.happens in the intake tract, or cylinder port.

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How system How system work:work:

Page 29: Gasoline electronic  fuel injection systems

• When the driver turns the ignition key When the driver turns the ignition key on, the power train control module on, the power train control module (PCM)(PCM) energizes a relay that supplies energizes a relay that supplies voltage to the fuel pump. The motor voltage to the fuel pump. The motor inside the pump starts to spin and runs inside the pump starts to spin and runs for a few seconds to build pressure in for a few seconds to build pressure in the fuel system. A timer in the PCM the fuel system. A timer in the PCM limits how long the pump will run until limits how long the pump will run until the engine starts.the engine starts.

• Fuel is drawn into the pump through Fuel is drawn into the pump through an inlet tube and mesh filter sock an inlet tube and mesh filter sock

• The fuel then exits the pump through a The fuel then exits the pump through a one-way check valve and is pushed one-way check valve and is pushed toward the engine through the fuel line toward the engine through the fuel line and filter.and filter.

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• The fuel filter traps any rust, dirt or other The fuel filter traps any rust, dirt or other solid contaminants that may have passed solid contaminants that may have passed through the pump to prevent such particles through the pump to prevent such particles from clogging the fuel injectors.from clogging the fuel injectors.

• The fuel then flows to the fuel supply rail on The fuel then flows to the fuel supply rail on the engine and is routed to the individual the engine and is routed to the individual fuel injectors. A fuel pressure regulator on fuel injectors. A fuel pressure regulator on the fuel rail maintains fuel pressure, and the fuel rail maintains fuel pressure, and recirculates excess fuel back to the tank.recirculates excess fuel back to the tank.

• The fuel pump runs continuously once the The fuel pump runs continuously once the engine starts, and continues to run as long engine starts, and continues to run as long as the engine is running and the ignition as the engine is running and the ignition key is on. If the engine stalls, the (PCM) will key is on. If the engine stalls, the (PCM) will detect the loss of the RPM signal and turn detect the loss of the RPM signal and turn the pump off.the pump off.

Page 31: Gasoline electronic  fuel injection systems

Finally :Finally :•what is Fuel Injection? it describes the way

the fuel (usually a liquid fuel) is injected (pumped under pressure) into some part of the engine where it can combine with the air charge in the cylinders and combustion can take place, releasing energy to propel the vehicle.

• What’s different about diesel [CI] engine injection? Diesel (compression ignition or CI ) and

petrol/gasoline (spark ignition or SI ) engines go about the task of releasing energy from their fuels in quite different ways.

Page 32: Gasoline electronic  fuel injection systems

• In fuel-injected spark ignition [SI] engines, fuel is always injected into the air charge well before ignition takes place. This necessary because the liquid or gaseous fuel must be thoroughly mixed together with air into a combustible mixture, able to be ignited by the electrical arc generated by the sparkplug. If the ratio of air to fuel is not reasonably close to 15:1 in the vicinity of the sparkplug, the mixture will not ignite at all and a miss-fire results.

Page 33: Gasoline electronic  fuel injection systems

• Compression ignition [CI] engines always inject the fuel charge directly into a combustion chamber in the engine. Fuel injection and ignition are inextricably tied together in compression ignition [CI] engines. Recall that CI engines only work because they compress the air charge so that it is hot enough to instantly ignite the fuel charge as it is being injected. The combustion of the fuel begins at the instant it begins being injected (well, within a couple of milliseconds, if you want to split hairs) into the combustion chamber full of very hot air (more than 400 ºC, often over 700 ºC).

• This means the timing of ignition is intimately tied to the fuel injection process. So, the fuel injection system of a CI engine is responsible for regulating both the quantity of fuel to be injected and timing of the beginning of combustion. Many ingenious techniques have been developed to achieve both these tasks with admirable accuracy, long before the advent of sophisticated electronic controls.

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How much fuel are we injecting here?• let’s do a few simple sums based on 1997 Land Rover

Discovery. It has a 4 cylinder 2.5 liter engine. At 100 km/h in 5th gear it’s doing very close to 2400 rpm or 2400/60 = 40 revolutions per second. Because it’s a 4 cylinder 4 stroke engine, it will be producing 2 power strokes every revolution, so that’s 80 power strokes per second. At a steady cruising speed of 100 km/h, it is likely to be covering 10 km/liter or, in other words, using 10 litres/100 km. Therefore, our fuel burn rate is 10 liters per hour or 10/3600 = 0.00278 liters per second = 2.78 mL/sec. Now, this 2.78 mL is shared between the 80 power strokes of the engine per second. So, for each power stroke of the engine while we are cruising at 100 km/h, the fuel injection system is delivering 2.78/80 = 0.03472 mL into each cylinder. Not much is it? And the injection system delivers precisely this quantity of fuel to one of the cylinders of the engine, 80 times per second and at the exact instant the cylinder needs to fire. Not bad for a completely mechanical system with no electronic “smarts” at all, is it?

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How much pressure?• SI engine (petrol/gasoline) injection systems typically run

at pressure of 2 to 3 bar (30 to 40 psi). In contrast CI (diesel) engines employ injection pressures of at least 350 bar (~5000 psi) and possibly in excess of 2000 bar (>29,000 psi) – quite a bit different to petrol/gasoline systems! This explains why CI injection systems are so solidly built and piped-up with strong steel tubing, etc.

• Petrol/gasoline readily vaporizes in the air stream entering the engine’s cylinders and in contact with the hot cylinder head surfaces, to form an easily ignitable air/vapor mixture. On the other hand, to instantly ignite the much less volatile diesel fuel in the hot air charge of a CI engine it is necessary to spray it into the combustion chamber in extremely small droplets. And to achieve this, extremely high injection pressures are required – the higher the better, in general.