7/08/2023
Many people look at their engine bay and question what a fuel injector does and why it’s proper operation is critical to your engines performance, economy and driveability.
Today I’ve decided to give you a breakdown of the construction of an injector to better help your understanding as to how many parts we carefully inspect and clean during our fuel injector services.
Petrol fuel injectors are a critical component of a modern fuel injection system. They are designed to deliver fuel to the engine’s combustion chambers and are usually positioned in the inlet manifold (with the exception of DI – or Direct Injection). A fuel injector works by spraying a precisely measured amount of fuel into the intake manifold near the intake valve. These precisely measured sprays are controlled by the ecu which controls the pulse width and duty cycle. Petrol fuel injectors are composed of several internal parts that work together to ensure efficient fuel delivery. Below is a breakdown of the internal and external components of a port-injected petrol fuel injector:
Spray Nozzle/Pintle: This is the part of the injector that sprays fuel into the manifold/combustion chamber. The nozzle has a small opening that controls the amount and angle of fuel spray. Many injectors vary in their spray patterns and angles to achieve the most efficient delivery of fuel for that particular engine. These spray nozzles can be found in a variety of different types ranging from single pintles, rotating disc and ball and seat. Each of these unique nozzles provide the correct spray pattern and angle to make the most efficient use of the fuel entering the engine.
Solenoid: The solenoid is an electromagnetic coil that controls the opening and closing of the injector. When the fuel injector receives an electrical signal from the engine control unit (ECU), the solenoid opens, allowing fuel to pass through the nozzle and into the combustion chamber during the appropriate combustion cycle. Externally the injector has two pins which is connected to the 12v source from the injector harness. These injector harnesses clip on to the injector and allow the ECU to supply power to the injector enabling it to control how it is operated under different engine conditions.
Injector Plug: The injector plug (or terminals) are built around a specific manufacturing mould. This is usually decided by the wiring harness that the manufacturer has decided to build. Common examples are Bosch, Denso and US car. They have a positive and negative terminal that recieves the injector pulse delivery by the ecu and in turn, powers the solenoid accordingly.
Valve: The valve is a spring-loaded component that controls the flow of fuel through the injector. When the solenoid is activated, the valve opens, allowing fuel to flow through the injector.
Filter basket: The basket filter is a small mesh screen located at the top of the injector that collects any debris or impurities in the fuel before it enters the injector. These filter baskets can be made of up various fuel safe materials such as, approved plastics and metal.
O-rings/Seals: O-rings are rubber seals that prevent fuel from leaking out of the fuel rail or preventing air leaking past the bottom of the injector. They are located at the top and bottom of the injector and are critical to the proper functioning of the fuel injection system. These seals take the shape of many different profiles and the correct sizing is critical to ensuring no leaks.
Buffers/spacers/caps: Sometimes fuel injectors require additional external parts in order to allow proper fitment. These can consist of different buffers, spacer rings, extensions or pintle caps. All of these parts ensure your injector seals and spray patterns remain in place and functioning correctly as per the design of the fuel injector.
All of these internal components work to deliver precise amounts of fuel into the engine’s combustion chamber allowing the engine to operated efficiently, reduce emissions and achieve optimized power.
Now that you have a better understanding of the components that make up an injector, it should be a lot clearer as to how important fuel injector maintenance is in order to keep all of the components fully functional. Need a fuel injector service? Give us a call or send a message through our contact form!
