Electronic fuel injection system efi basics car craft. The engine control unit ecu may be either analog or digital, and the system may or may not have closedloop lambda control. We often get questions about our fuel pressure regulator, how it works, what role it plays in a fuel system and what it is that makes us promise that it is suitable for even over hp. Some early efi systems use throttle body injection tbi which uses a throttle body with electronic fuel injectors built inside. Most car engines use port injection or a carburetor. The fuel injection system consists of many sensors positioned all around your vehicle as shown in the fig. Each of the following should be considered in an effort to ensure your fuel system works efficiently and reliably. See how oil injection works and all of its components work. Since then, fuel injectors have been the primary means of getting gasoline into the engine. The kjetronic pump requires no form of drive and one of its features is that it can meter the fuel as a function of the intake air quantity. Electronic fuel injection delivers much more accurate fuel delivery today, but it wasnt always so efficient. Its the highpressure fuel rail and the computer controlled electronic injectors that make all the difference. Luckily though, the efi system has been continuously refined over the years and the newest electronic sequential port fuel injection espfi system is reliable and dare we say itbetter than any carb ever made for the precise regulation of fuel delivery. If you didnt already know, efi systems operate at a much higher fuel pressure than do carburetors.
Thus, fuel pressurization, atomization, fuel distribution, and injection timing are accomplished in just one component. The computer then compares that data to a stored map of fueling requirements. But have you ever stopped to think about how the fuel gets from the fuel tank into your engine. Fuel is delivered to the throttle body injection system by an electric fuel pump located in the fuel tank. The 1954 mercedesbenz w196 formula 1 racing car engine used bosch direct injection derived from wartime aircraft engines. All electronic fuel injection systems work in essentially the same way. Electronically controlled mechanical fuel injection. A tbi system also makes it easier for an electronic engine control system to regulate the fuel mixture than an electronic feedback carburetor. In a unit injection system, the nozzle and injection pump are integrated into one module. Find out how basic electronic fuel injection works and why the system superseded the classic carburettor.
Fuel injectors are small electromechanical devices that are used to spray fuel into the intake manifold directly in front of the intake valve. Nissan offered electronic, multiport fuel injection in 1975 with the bosch ljetronic system used in the nissan l28e engine and installed in the nissan fairlady z. The computer controls how long the injector stays open or in some cases how quickly it opens and closes. It gives the clear idea about how to work a fuel injection system. Principle and working of electronic fuel injection system.
Kjetronic fuel injection system kjetronic is a mechanically and hydraulically operated fuel injection pump, introduced by bosch gmbh in the year 1973. As many people already know, an engine is a system which transforms chemical energy into mechanical energy. Many modern cars come with electronic injection systems. System operation of a fuel injection ecu system a fuel injection ecu works by pulsing or controlling the fuel injectors in the engine. An electric fuel pump provides the fuel at a constant fuel pressure. The last carburetorequipped car came off the assembly line in 1990. A fuel injector is a solenoid that opens and closes allowing fuel to pass through it. Electronic fuel injection efi electronic fuel injection allows for extremely precise control over how much fuel is sprayed into the cylinders. A highpressure electric pump is required to generate pressure so fuel will spray out of the fuel injectors when the injectors open. The injector has a final high micron filter in the top inlet side and small hypodermicsized holes on the bottom for the atomizing of.
It helps in pumping gasoline from the vehicles fuel tank to the engine and distributes fuel to fuel injection system under higher pressure. Electronic controls modulate the duty cycle of electronic fuel injection for the throttle position and other factors. Electronic fuel injection can be programmed to work best for a certain use such as towing or drag racing, and this electronic tuning takes less time than mechanical fuel injection and doesnt need to be retuned as much as a carbureted system. Understanding your cars fuel injection system haynes. One big difference between a diesel engine and a gas engine is in the injection process. The fuel injection unit has an electrical pump which is pressurized so that the fuel can be injected easily and with force to make sure the amount of fuel is accurate. In the common rail system, the fuel pump charges the fuel rail at a pressure of up to 25,000 psi. Traditional indirect fuel injection systems premix the gasoline and air in a chamber just outside the cylinder called the intake manifold.
This video is the working principle animation of electronic fuel injection system. A fuel injection ecu works by pulsing or controlling the fuel injectors in the engine. In essence, these are almost the same as mechanical fuel injection systems except that they are not dependent on the amount of fuel and spring tension to open and close the valve of the injectors. How pgmfi electronic fuel injection works monocilindro. Check out how an electronic fuel injection system can put in your high performance engine, check it out in the february issue of car craft magazine or at. The cummins hpi fuel injection system is an important fuel injection system used in heavyduty and high horsepower engines since the mid1990s. Gasoline engines work by sucking a mixture of gasoline and air into a cylinder, compressing it with a piston, and igniting it with a spark. Carburetors were the goto fuel delivery system for many decades. An electronic unit injector system is installed directly into a cylinder head over every combustion chamber. Everyone knows that you put fuel into the tank to keep the car running. To wrap it up in short, the fuel is directly injected into the combustion chamber of the engine.
If the injector ground circuit is turned on the fuel is sprayed at the back of the intake valve. There is a difference in the way these systems operate. On the other hand, the fuel injection system has been around since the 1950s and electronic fuel injection efi was installed in european cars during the 1980s. How a fuel injection ecu engine control unit system works. A carburetor mixes air and fuel long before the air enters the cylinder. Once it finds what it likes, it tells the injector to remain open and spraying fuel for a given length of time. A fuel pump sends the petrol to the engine bay, and it is then injected into the inlet manifold by an injector.
Modern digital electronic fuel injection systems optimize these competing objectives more effectively. A cars ecu is primarily responsible for four tasks. At its most basic, the system works by comparing the throttle angle or alpha to the engine rpm, or n. Depending on the particular system, the fuel is fired into either the inlet manifold or the inlet port via an injector. The system is based on the kjetronic mechanical system, with the addition of an electrohydraulic actuator, essentially a fuel injector inline with the fuel return. In continue reading how pgmfi electronic fuel injection. Today, thats not that case, as electronic throttle control systems allow the ecu to open and close the butterfly valve via a stepper motor. Principle and working of electronic fuel injection system all modern vehicles are provided with a fuel injection system to convey fuel to the engine while reducing the amount of harmful emissions that a vehicle emits off. The computer regulates the electronic fuel injector pulse width the time that the fuel injector is open and ignition lead with input from various sensors. This is done by switching the injector ground circuit on or off. Check out how the high pressure oil injection system heiu works as we look at the complete oil injection works. A special pump sends the fuel under pressure from the fuel tank to the engine bay where, still under pressure, it is distributed individually to each cylinder. This is done by switching the injector ground circuit on or off depending on what is required by the engine.
The diesel fuel injection system has undergone many changes over the years. Fuel injection is the introduction of fuel in an internal combustion engine, most commonly. Principle behind mpfi the power is produced in a petrol engine is by burning the fuel. They were cheap to manufacture and easily adapted to new engines and higher power requirements. Previously, cars used to have a carburetor installed in them, but such cars are no longer on the market. A typical carbureted system requires between 5 and 7 psi of fuel. In japan, the toyota celica used electronic, multiport fuel injection in the optional 18re engine in january 1974. It is then ignited in a cylinder called as the combustion chamber. How electronic fuel injection efi works how to motorcycle. Virtually every vehicle built since the late 1980s and early 1990s have been equipped with some type of electronic fuel injection.
Manufacturers looked to efi to solve their complex emissions problems. We carry many efi systems many selftuning and selflearningfrom the top players in engine performance, including msd ignition, edelbrock, holley, fast, accel, chevrolet performance, quick fuel, and more. Take our quiz to find out how much you know about fuel injection systems. Here we answer those questions and more what is a fuel injection system. A basic understanding of how components work will allow testing of nearly all parts of a fuel injection system. But unlike indirect injection pumps, it is not involved in fuel discharge. Find out how fuelinjection systems work and about the various configurations used in the cars today.
There are a number of different fuel injection systems out there, but they can all be sorted into two categories. Modern cars use electronic fuel injection systems that are controlled by. Since then, fuel injectors have been the primary means of getting gasoline into the engine cylinder so it can combust and you can drive. Electronic fuel injection efi electronic fuel injection allows for extremely precise control over how much fuel. Because of that, fuel pumps are a popular product line for shops to carry. What you need to know about mechanical fuel injection. To compare, electronic fuel injection efi works with a similar air valve although it may be throttle controlled or controlled electrically. Unlike carburetors, a fuel injection system is comprised of a complex set of electronics and sensors.
Ph explains find out how basic electronic fuel injection works and why the system superseded the classic carburettor. In carbureted systems the fuel gets drawn from the tank, while in a fuel injected system it depends on a fuel pump installed inside the tank for a finegrained control over fuel flow. What are electronic unit injectors and how do they work. There are two versions of this fuel system that carry the designations hpipt and hpitp using pressuretime and time. Learn how fuel injection systems work on this page. Multiport injection systems fire the injectors in groups. Electronic fuel injection systems for heavyduty engines. How does a multipoint fuel injection system work in a. Understanding electronic fuel injection know your parts. This pump supplies fuel pressure in sufficient volume to meet the engines fuel requirement through all load conditions. Take a technological leap forward with a new electronic fuel injection system from summit racing. Modern electronic fuel injection lets engines make more power and run more efficiently than older designs.
Electronic fuel injection efi replaced carburetors back in the mid1980s as the preferred method for supplying air and fuel to engines. Its generally reliable but it still pays to know how the system works, where it is and how to tell when its playing up. The resulting explosion drives the piston downwards, producing power. A port injection system injects fuel just prior to the intake stroke outside the cylinder. In its early days fuel injection was expensive and associated with premium vehicles but now every car has fuel injection. Efielectronic fuel injection systems at summit racing. Here we will go through the basics, how it works, how it functions in a fuel system and explain the different parts.
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