Since the introduction of the fuel injection system, the truck industry has been able to have the following advantages: reduce truck emissions, improve fuel mileage, and produce more reliable engines. Initially, the injectors are used to discharge fuel into the combustion chamber. Today, however, truck injectors the hardware that has been precisely adjusted. Truck owners have a better understanding of the truck fuel injector will be critical to the life and reliability of the truck.
What are fuel injectors？
The fuel injector of the truck is a kind of precision equipment with very high machining accuracy, which requires a large dynamic flow range, strong anti-clogging and anti-pollution capabilities, and good atomization performance. The fuel injector receives the fuel injection pulse signal sent by the ECU and accurately controls the fuel injection quantity. The spray characteristics of the fuel injector include atomized particle size, fuel spray distribution, fuel spray direction, range, and diffusion cone angle. These characteristics shall meet the diesel engine combustion system’s requirements to make the mixture form and combustion perfect and obtain higher power and thermal efficiency.
Classification of fuel injectors
There are four main types of fuel injectors for trucks. Spindle needle types electromagnetic injector, ball valve type electromagnetic injector, disc valve type electromagnetic injector, and lower fuel inlet injector.
- Spindle needle-type electromagnetic injector
When injecting oil, the armature drives the needle valve to rise from its seating surface, and fuel is ejected from the precision clearance. In order to fully atomize the fuel, a section of the fuel injection shaft needle is ground at the front end of the needle valve.
- Ball valve-type electromagnetic injector
The valve needle of the ball valve is light, and the spring preload is large, which can obtain a wider dynamic flow range. The ball valve has an automatic centering function and good sealing performance. At the same time, the ball valve simplifies the structure of the metering part, which is helpful to improve the accuracy of fuel injection.
- Slice valve electromagnetic injector
The combination of a light valve plate and hole valve seat with the magnetically optimized injector assembly gives the injector a large dynamic flow range and a strong anti-clogging ability.
- Fuel injector at the lower part
The bottom fuel supply mode is adopted, which has a very obvious cooling effect on the metering part of the fuel injector, so it can effectively prevent air lock and improve the reliability of the hot start of the vehicle. In addition, the fuel injector with the bottom injection can save the fuel manifold and reduce the cost.
Operating principle of fuel injector
The injector is actually an electromagnetic switching device. It has two ends, one connected to the power supply to prepare for driving, and the other connected to the ECM to control the grounding. When the ECM controls the injector coil to be grounded, the coil conduction current generates electromagnetic force to overcome the gravity and friction of the needle valve, the force of the return spring, and the pressure of the fuel. The needle valve is sucked up, and the fuel is injected into the intake manifold through the valve hole. When the injection pulse is cut off, the pressure of the return spring makes the needle valve close again. The time when the injector solenoid is energized is called the injection pulse width and is controlled by the ECM. The greater the injection pulse width, the more fuel is injected into the truck.
The function of the truck fuel injector
The function of the fuel injector is to inject fuel into the intake manifold or cylinder according to the fuel injection timing and pulse width calculated by the engine ECU. The injector is actually a solenoid valve. The ECU controls the operation of the fuel injector by controlling the current of the solenoid valve coil of the fuel injector. The fuel injector is an important component in maintaining engine operation, which is composed of a fuel injector, bracket, spring, etc. High-pressure oil is pumped into the fuel supply port of the injector. High pressure is generated in the injector body and acts on the cone of the injector. When the oil pressure exceeds the set value, the valve core of the fuel injector opens, and high-pressure oil is sprayed out of the nozzle hole, burning in the form of fog in the engine cylinder barrel, so that the piston operates reciprocally.
Benefits of Fuel Injectors
The injector has the following advantages: the first advantage is that it can provide the best air-fuel ratio according to the change of engine working conditions; The second advantage is that it can be supplied to the mixture of each cylinder with the same air fuel-ratio and the same amount; The third advantage is that the intake pipe of the fuel injector has no narrow throat, so the intake resistance is small and the inflation performance is good. The fourth advantage of the fuel injector is that it can improve the difficulty of engine cold start to a certain extent.
Cost of replacing the truck injector
In fact, the truck fuel injector is very reliable. If you maintain it regularly, you should have nothing to worry about. However, in some cases, you may have no choice but to replace the complete injector:
- If you detect an obvious fuel leak in the injector body, it must be replaced.
- It is recommended to replace the fuel injector after an engine overhaul.
- If you have never repaired the fuel injector completely, you may need to replace the fuel injector after 50000 miles of continuous use.
If the above situation occurs in your truck, you need to replace the fuel injector of the truck. The price of replacing the internal parts of the fuel injector varies from two to three hundred yuan. For ordinary trucks, the price of new fuel injectors is between 1000 and 1500 yuan. Generally speaking, we need to replace the new fuel injector.
