The basic difference is that a carburetor uses intake vacuum and a pressure drop in the venturi the narrow part of the carburetor throat to siphon fuel from the carburetor fuel bowl into the engine whereas fuel injection uses pressure to spray fuel. 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. Electronic fuel injection efi replaced carburetors back in the mid1980s as the preferred method for supplying air and fuel to engines. 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. Principle and working of electronic fuel injection system. Multiport and sequential fuel injection systems both inject atomized fuel into a port just before the intake valve. Previously, cars used to have a carburetor installed in them, but such cars are no longer on the market. As many people already know, an engine is a system which transforms chemical energy into mechanical energy. Find out how basic electronic fuel injection works and why the system superseded the classic carburettor. In the common rail system, the fuel pump charges the fuel rail at a pressure of up to 25,000 psi. Multiport injection systems fire the injectors in groups.
Electronic fuel injection efi electronic fuel injection allows for extremely precise control over how much fuel. Check out how the high pressure oil injection system heiu works as we look at the complete oil injection works. This is done by switching the injector ground circuit on or off depending on what is required by the engine. All electronic fuel injection systems work in essentially the same way. The 1954 mercedesbenz w196 formula 1 racing car engine used bosch direct injection derived from wartime aircraft engines. A port injection system injects fuel just prior to the intake stroke outside the cylinder. Electronic fuel injection delivers much more accurate fuel delivery today, but it wasnt always so efficient. The computer then compares that data to a stored map of fueling requirements. 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.
Efielectronic fuel injection systems at summit racing. In its early days fuel injection was expensive and associated with premium vehicles but now every car has fuel injection. Ph explains find out how basic electronic fuel injection works and why the system superseded the classic carburettor. A carburetor mixes air and fuel long before the air enters the cylinder. Most car engines use port injection or a carburetor. Modern electronic fuel injection lets engines make more power and run more efficiently than older designs. The last carburetorequipped car came off the assembly line in 1990. The fuel injection system consists of many sensors positioned all around your vehicle as shown in the fig. A fuel pump sends the petrol to the engine bay, and it is then injected into the inlet manifold by an injector. A fuel injector is a solenoid that opens and closes allowing fuel to pass through it. 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.
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. A typical carbureted system requires between 5 and 7 psi of fuel. 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. 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. Virtually every vehicle built since the late 1980s and early 1990s have been equipped with some type of electronic fuel injection. There are two versions of this fuel system that carry the designations hpipt and hpitp using pressuretime and time.
Understanding electronic fuel injection know your parts. An electronic unit injector system is installed directly into a cylinder head over every combustion chamber. There are a number of different fuel injection systems out there, but they can all be sorted into two categories. 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. If you didnt already know, efi systems operate at a much higher fuel pressure than do carburetors. Here we answer those questions and more what is a fuel injection system.
How a fuel injection ecu engine control unit system works. To wrap it up in short, the fuel is directly injected into the combustion chamber of the engine. Manufacturers looked to efi to solve their complex emissions problems. This pump supplies fuel pressure in sufficient volume to meet the engines fuel requirement through all load conditions. Take our quiz to find out how much you know about fuel injection systems.
Take a technological leap forward with a new electronic fuel injection system from summit racing. In continue reading how pgmfi electronic fuel injection. If the injector ground circuit is turned on the fuel is sprayed at the back of the intake valve. One big difference between a diesel engine and a gas engine is in the injection process. Principle behind mpfi the power is produced in a petrol engine is by burning the fuel.
Its generally reliable but it still pays to know how the system works, where it is and how to tell when its playing up. A cars ecu is primarily responsible for four tasks. This video is the working principle animation of electronic fuel injection system. An electric fuel pump provides the fuel at a constant fuel pressure. Find out how fuelinjection systems work and about the various configurations used in the cars today.
How pgmfi electronic fuel injection works monocilindro. Once it finds what it likes, it tells the injector to remain open and spraying fuel for a given length of time. It helps in pumping gasoline from the vehicles fuel tank to the engine and distributes fuel to fuel injection system under higher pressure. The resulting explosion drives the piston downwards, producing power. At its most basic, the system works by comparing the throttle angle or alpha to the engine rpm, or n. They were cheap to manufacture and easily adapted to new engines and higher power requirements. The engine control unit ecu may be either analog or digital, and the system may or may not have closedloop lambda control. What are electronic unit injectors and how do they work. 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. How does a multipoint fuel injection system work in a. Some early efi systems use throttle body injection tbi which uses a throttle body with electronic fuel injectors built inside. There is a difference in the way these systems operate. How electronic fuel injection efi works how to motorcycle. A tbi system also makes it easier for an electronic engine control system to regulate the fuel mixture than an electronic feedback carburetor.
Understanding your cars fuel injection system haynes. Because of that, fuel pumps are a popular product line for shops to carry. Fuel injectors are small electromechanical devices that are used to spray fuel into the intake manifold directly in front of the intake valve. Since then, fuel injectors have been the primary means of getting gasoline into the engine cylinder so it can combust and you can drive. 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. Depending on the particular system, the fuel is fired into either the inlet manifold or the inlet port via an injector. Electronic fuel injection systems for heavyduty engines. This is done by switching the injector ground circuit on or off. Each of the following should be considered in an effort to ensure your fuel system works efficiently and reliably. Unlike carburetors, a fuel injection system is comprised of a complex set of electronics and sensors. What you need to know about mechanical fuel injection. A fuel injection ecu works by pulsing or controlling the fuel injectors in the engine. But unlike indirect injection pumps, it is not involved in fuel discharge. See how oil injection works and all of its components work.
It gives the clear idea about how to work a fuel injection system. The cummins hpi fuel injection system is an important fuel injection system used in heavyduty and high horsepower engines since the mid1990s. Electronic fuel injection system efi basics car craft. The injector has a final high micron filter in the top inlet side and small hypodermicsized holes on the bottom for the atomizing of. 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. Everyone knows that you put fuel into the tank to keep the car running. In japan, the toyota celica used electronic, multiport fuel injection in the optional 18re engine in january 1974. To compare, electronic fuel injection efi works with a similar air valve although it may be throttle controlled or controlled electrically. 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.
Its the highpressure fuel rail and the computer controlled electronic injectors that make all the difference. In a unit injection system, the nozzle and injection pump are integrated into one module. Thus, fuel pressurization, atomization, fuel distribution, and injection timing are accomplished in just one component. 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. The computer controls how long the injector stays open or in some cases how quickly it opens and closes. Fuel is delivered to the throttle body injection system by an electric fuel pump located in the fuel tank. All modern petrol injection systems use indirect injection. 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. Here we will go through the basics, how it works, how it functions in a fuel system and explain the different parts. Carburetors were the goto fuel delivery system for many decades.
Learn how fuel injection systems work on this page. A basic understanding of how components work will allow testing of nearly all parts of a 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. Electronic controls modulate the duty cycle of electronic fuel injection for the throttle position and other factors. But have you ever stopped to think about how the fuel gets from the fuel tank into your engine.
Modern cars use electronic fuel injection systems that are controlled by. 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. Modern digital electronic fuel injection systems optimize these competing objectives more effectively. 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.
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. Since then, fuel injectors have been the primary means of getting gasoline into the engine. The diesel fuel injection system has undergone many changes over the years. Today, thats not that case, as electronic throttle control systems allow the ecu to open and close the butterfly valve via a stepper motor. It is then ignited in a cylinder called as the combustion chamber. Fuel injection is the introduction of fuel in an internal combustion engine, most commonly. Electronically controlled mechanical fuel injection. Traditional indirect fuel injection systems premix the gasoline and air in a chamber just outside the cylinder called the intake manifold. Electronic fuel injection efi electronic fuel injection allows for extremely precise control over how much fuel is sprayed into the cylinders.
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