How Fuel Injection Systems Work. The simplest explanation is that air is sucked into an engine by atmospheric pressure. Air is then measured by sensors that indicate air mass flow. An ECM processes these signals and calculates the desired air/fuel ratio, producing a pulse width to allow optimal combustion. Modern systems treat each injection as a discrete event that performs seamlessly, much like a motion picture.
Direct injection
One of the biggest concerns with modern automakers’ use of direct fuel injection is the complexity of the systems. High-pressure fuel systems are challenging to manufacture and require special attention to make them reliable. Additionally, they are expensive to maintain and repair. However, companies have mastered the technology and outsourced the process to lower costs. Direct injection represents a clear step forward in the evolution of gasoline engine design and offers notable benefits for tuning and fuel economy. Manufacturers will likely work out the kinks and improve their reliability as they continue to use this system for future vehicles.
While initially developed for two-stroke engines, direct fuel injection found commercial success with four-stroke engines. As a result, Mitsubishi Motors launched the first modern gasoline direct injection automotive engine, the 1.8-liter straight-4, on the market in Europe by 1997. By 2001, Mitsubishi had manufactured more than one million GDI engines across four families. Toyota and Mazda followed suit in 1997 and produced their first DI engines and the GDI technology.
Indirect injection
Indirect fuel injection systems inject the fuel into separate chambers outside the cylinders. This replaces the carburetor. The fuel is then mixed with the air that enters the engine through the induction system, which sprays it into the combustion chamber. A glow plug heats the chamber during cold starts, creating a charge that ignites due to increased pressure and temperature. Modern technology has recently used a direct injection system where the diesel fuel is sprayed directly into the combustion chamber.
A primary advantage of an indirect injection system is that it is simpler to design and manufacture. It can be used on both diesel and petrol engines. However, the indirect injection system has lower fuel efficiency. Indirect methods are often considered a compromise between direct and indirect injection. The indirect injection has fewer internal components and is less expensive to manufacture. The only drawback of an indirect injection system is that it has a lower efficiency than a direct system.
Sequential injection
Sequential systems fire each injector in a discrete amount at a time. They also change the fuel mixture instantaneously, unlike multiport systems. This means a sequential system is more efficient than a multiport system. In addition, each injector is given specific pulse width, meaning that the amount of fuel injected is precise to each induction event.
The benefits of sequential fuel injection systems are many. A sequential system prevents a misfire or multiple misfires because the fuel charge in some cylinders sits momentarily before firing in others. However, it’s not perfect for all cars.
Hydraulic direct injection
The hydraulic direct injection in fuel induction system uses a high-pressure oil system to supply a large volume of diesel fuel to an injector. Similarly, the piston or intensifier acts as a valve to control the amount of fuel delivered. This pressure is then increased by the ECM, which sends a signal to the injector solenoid to activate the injector. The result is that the injection pressure reaches a level where the fuel can be delivered to the combustion chamber.
One type of hydraulic direct injection in a fuel injection system is a VE pump. It works on the same principle as the VE pump but produces a lower pressure. The pressure is generated by a differential piston and multiplied by four. A small check valve prevents cavitation in the pipe. The VE pump produces 30 MPa of pressure, and the high-pressure chamber fills through a smaller check valve. In addition, a specially designed delivery valve prevents cavitation.
Electronic fuel injection
EFI stands for electronic fuel injection systems. They are often installed in modern cars and trucks. A certain company invented the electrojector system in the mid-1960s, and other automakers followed suit. Volvo, Mercedes-Benz, and Citroen also produced electronic fuel injection systems. Honda, Toyota, and others eventually used them. The new systems can operate with various fuels, from light to heavy. The system can also monitor engine performance to prevent problems before they arise.
Early fuel injection systems monitored airflow and acted as a flap valve, sending more gasoline into the engine. This was an inefficient system that wasted a lot of gasoline. Today, electronic fuel injection systems use several variables to manage the air-fuel mixture and prevent carbon deposits in mechanical parts. These systems also help improve the fuel economy of your car. And, they’re much more reliable than carburetors. In the United States, all vehicles sold must have one.
