Types of The Fuel Injector

Brief introduction of the fuel injector

The electronically controlled fuel injector is the most critical and complex component in the common rail system, and it is also the most difficult component in design and process. By controlling the opening and closing of the solenoid valve, the ECU (electronic control unit) injects the fuel in the high-pressure fuel rail into the combustion chamber with the best fuel injection timing, fuel injection quantity and fuel injection rate. In order to achieve an effective fuel injection starting point and precise fuel injection quantity, the common rail system uses a special fuel injector with a hydraulic servo system and an electronic control element (solenoid valve). There are many fuel injector brandsn and their application is wide, such as, cat 3116 injector, fitting engine 3116 and 3114.

Fuel injection process

1. The fuel injector is equivalent to a solenoid valve.

2. When energized, the electromagnetic coil generates electromagnetic force, the armature and the needle valve are sucked up, the fuel injector is opened, and gasoline is sprayed into the intake port or intake pipe through the injection hole.

3. When the power is off, the electromagnetic force disappears, the armature and the needle valve close the nozzle hole under the action of the return spring, and the fuel injector stops injecting fuel.

4. The power-on and power-off of the fuel injector are controlled by electric pulses by the electronic control unit.

5. The fuel injection quantity is determined by the electric pulse width. Pulse width = fuel injection duration = fuel injection volume.

6. Generally, the lift of the needle valve is about 0.1mm, and the fuel injection duration is in the range of 2~10ms.

Types of the fuel injector

Axial Electromagnetic Injector

When fuel is injected, the armature drives the needle valve to rise about 0.1mm from its seat surface, and the fuel is sprayed out from the precision gap. In order to fully atomize the fuel, a section of fuel injection shaft needle is ground at the front end of the needle valve. The suction and fall time of the injector is about 1-1.5ms.

Ball Valve Electromagnetic Injector

The valve needle of the ball valve is light in weight and the spring preload is large, which can obtain a wider dynamic flow range. The ball valve has self-centering function and good sealing performance. At the same time, the ball valve simplifies the structure of the metering part, which helps to improve the accuracy of fuel injection.

Chip Valve Electromagnetic Injector

The combination of light weight valve plate and orifice valve seat and magnetically optimized fuel injector assembly makes the fuel injector not only have a large dynamic flow range, but also have strong anti-clogging ability.

Lower fuel injector

The bottom fuel supply method is adopted, since the fuel can flow out continuously from the upper part through the inner cavity of the fuel injector around the valve seat area, the cooling effect on the metering part of the fuel injector is very obvious, so it can effectively prevent the generation of air resistance and improve the hot start of the car reliability. In addition, injectors that use bottom injection can save fuel rails and help reduce costs.