How it Works EFI System

How it Works EFI System

EFI system or PGM-FI (Honda's term in) is designed to be able to do the spraying of fuel and the amount of time is determined based on information from the sensors. Fuel ratio correction setting and the air is very important for the machine can still operate / work perfectly on a variety of working conditions. Therefore, the presence of sensors that provide accurate information about the condition of the engine when it is determining performance (performance) of a machine. The more complete the sensor, the detection of various character engine conditions (temperature, pressure, rotation, gas content, engine vibration, etc.) the better. This information is very useful for ECU to be processed in order to provide the proper command to the injectors, ignition system, fuel pump and so on.

a. Current injection (injection timing) and duration of injection

There are several types of injection (spraying) in motor gasoline EFI system (especially the number of cylinders having two or more), including simultaneous injection type (simoultaneous injection) and injection type separately (independent injection). Type the simultaneous injection of current injection occur simultaneously, while a separate type of injection is the injection time of each injector is different from one another, usually in the order of ignition or firing order (FO). As was mentioned previously that the injection of the motor gasoline is generally done at the end of the intake valve manifod before the inlet (inlet valve). Therefore, the current injection (injection timing) is not necessarily exactly the same as spark plugs, which is a few degrees before TDC at the end of the compression stroke. When the injection is not a problem even occurs on the steps of suction, compression, businesses and the waste due to the injection before the inlet valve. This means that when the injection is directly into the combustion chamber during the intake valve position is still in a state close. For example for 4-cylinder engine with simultaneous injection type, of course, when the injection injector from one to another occurs simultaneously. If the FO machine is 1 - 3 - 4-2, when the injection on cylinder 1 on the suction step, then the injection cylinder 3 occurred in a previous step, the step waste. Next on 4-cylinder injection occurs at the step of business, and the second cylinder on the compression stroke injection occurs. While the length (duration) injection will vary depending on the engine working conditions. The longer the place of injection, the amount of fuel will be more and more also. Thus, as rising round of the engine, then the duration of the injection will be growing because of the fuel needed more and more.

b. How it Works When the Cold Machine Condition

At the time the engine is still cold conditions (ie when you turn in the morning), it would require a mixture of fuel and more air (rich mixture). This is due to the evaporation of fuel during conditions of low temperature / low temperature. Thus there will be a small fraction of fuel on the wall so it does not enter the intake manifold and burned in the combustion chamber. To enrich the fuel-air mixture, the EFI system is equipped with a water cooling system are the cooling water temperature sensor (engine / coolant temperature sensor) as shown in the image below. These sensors will detect the condition of the engine cooling water is still cold. Cooling water temperature is detected and converted into electrical signals sent to the ECU / ECM. Furthermore ECU / ECM will process them and then give the command to the injector to deliver voltage to the solenoid longer fuel injector to spray a lot more (wealthy).

Image sensor Cooling Water (9) Yamaha GTS 1000

While the engine is not equipped with water cooling system, the dominant sensor for detecting the condition of the engine is cold when the temperature sensor oil / lubricants (engine oil temperature sensor) and the intake air temperature sensor (intake water temperature sensor). Engine oil temperature sensor detects the lubricant condition was still cold, then converted into electrical signals and sent to the ECU / ECM. While the intake air temperature sensor detects the temperature of air entering the intake manifold. At the still cold air is more dense so that the density of the air molecules more than the temperature at which the heat. In order to stay there the comparison is still close to the ideal mixture, the ECU / ECM will provide a voltage to the solenoid injector slightly longer (rich). Thus, the low fuel evaporation when the temperature is low so there will be fuel on the walls of the intake manifold can be anticipated by enriching the mixture.

Picture Engine Oil Temperature Sensor and Intake Air Temperature Sensor Honda Supra X 125

c. How it works At Low Round

At low engine speed and engine temperature has reached its temperature, the ECU / ECM will control and provide power to the injector is short (a few degrees of crank) because the amount of gas detected by the MAP sensor and throttle position sensor (TP sensor) is still small. It is possible to keep the ratio of fuel and air mixture is right (close to the theoretical or ideal mixture ratio). The position of the gas valve (throttle valve) on the throttle body is closed at the time of rotation stationary / slow (stationary spin on a motorcycle is generally around 1400 rpm). Therefore, the air flow is detected from a special channel for stationary channels. Most of the EFI system on the motorcycle is still using the screw setter (air idle adjusting screw) for stationary rotation.

Line drawings stationer We Go Round Valve To Throttle Still Closes In Motorcycles Honda Supra X 125

Based on information from the air pressure sensor (MAP sensor) and the throttle position sensor (TP) sensor, the ECU / ECM will provide an electrical voltage to the solenoid injector to spray fuel. The duration of spraying / injection of only a few degrees of crank just because of fuel required is still small. At the engine speed slightly increased but still fall into the low speed, air pressure is detected by the MAP sensor would be higher than during the stationary lap. Rising air pressure indicates that the amount of incoming air entering more. Based on the information obtained by the MAP sensor, the ECU / ECM will provide a voltage slightly longer than the current round of satsioner.

Picture Position Round screw adjusters Stationary On Throttle Body

Pictured above is an illustration when the engine rotates at low speed, ie 2000 rpm. As shown in the figure, when spraying / injection (fuel injection) occurred at the end of step length exhaust and spraying / injection is also still a few degrees of crank just because of fuel required is still small.

Sample images In the injector spraying Round At 2000 rpm

As was mentioned earlier that the process occurs when the spray injector ECU / ECM to provide voltage to the solenoid injector. By giving the solenoid coil voltage will become a magnet so as to attract the plunger and the raised needle valve (needle valve) of the holder, so that the fuel in the fuel lines that are pressurized will radiate out from the injector.

d. How it Works When the round of Secondary and Higher

At the engine speed is increased and the condition of the engine under normal circumstances, the ECU / ECM receives information from the gas valve position sensor (TP sensor) and the MAP sensor. TP sensor detects the opening of the throttle valve while the MAP sensor detects the amount / air pressure is growing up. Currently obtained by the sensor detection indicates the amount of air entering more and more. The sensors send information to the ECU / ECM in the form of electrical signals. ECU / ECM then process and will provide an electric voltage to the solenoid injector with a longer time than the previous round. Besides, when ignition is also automatically forwarded to remain achieve optimum combustion based on the flow of information obtained from the rotation sensor rpm. Picture below is an illustration when the engine is spinning at high spin, ie 4000 rpm. As shown in the figure, when spraying / injection (fuel injection) is taking place from mid-step business until mid-wasting steps and duration of spraying / injection of nearly half the degrees of crank rotation for the fuel needed more and more. The next round if the round is raised again, the throttle valve is more wide open and the throttle valve position sensor (TP sensor) detects the change of the throttle valve. ECU / ECM memerima information changes the throttle valve is in the form of electrical signals and will provide a voltage to the solenoid injector for longer than the middle rounds because of the fuel needed more. Thus the length of the spraying / injection will automatically be in excess of half a degree crankshaft rotation.

Sample images In the injector spraying Round At 4000 rpm

e. How it Works When the acceleration (Acceleration)

When the motorcycle accelerated (gassed) with simultaneous from low speed, then the volume of air will also increase rapidly. In this case, because the fuel is heavier than air, it will temporarily delay resulting fuel mixture of thin / poor. To overcome this, the conventional fuel system (using a carburetor) system equipped with acceleration (acceleration) that will inject an additional amount of fuel through special channels. While the injection system (EFI) does not make a special corrections during acceleration. This is due to the EFI fuel system there is high pressure in the channel. Changes in the air when the throttle is opened suddenly to be detected by the MAP sensor. Although the MAP sensor is detected air pressure, but basically also determines the amount of air. The higher the air pressure is detected, the more the amount of air entering the intake manifold. Thus, during acceleration the EFI system does not delay the delivery of fuel because the fuel has a high pressure is injected simultaneously in accordance with changes in the volume of incoming air. Thus was how the EFI system on several machines working conditions. There are still some engine work conditions that are not discussed in more detail such as when slowing down (deceleration), during the energy released (high power output) or heavy loads and so on. But the principle is similar to the explanations that have been discussed. This is due to the EFI system all the corrections to the timing / duration of current injection and injection based on the information ¬ information provided by the existing sensors. That information is sent to the ECU / ECM in the form of electrical signals, which is an overview of the various working conditions at that time machine. The more complete the sensor is mounted on a machine, then the correction to the current arrangements and the duration of the injection will be more perfect, so the machine can produce the performance or display (performance) is optimal and the issue content of the minimal toxic emissions.

source: http://rescocommunity.wordpress.com/2010/02/23/cara-kerja-mesin-efi/

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