How is the fuel injection quantity of a car detected?

Computer testing. The fuel injection quantity is controlled by computer. The computer calculates the engine intake, speed, throttle opening, water temperature, intake temperature and many other operating parameters measured by various sensors according to the set program.

According to the calculation results, electric pulses are sent to the fuel injector, and the duration of each fuel injection is controlled by changing the width of each electric pulse, so as to control the fuel injection quantity. The greater the width of the electric pulse, the longer the fuel injection duration and the greater the fuel injection quantity.

The fuel injection quantity of fuel injector depends on three factors: nozzle size, fuel injection pressure and fuel injection duration. The fuel nozzle is strictly matched with the fuel pump and fuel pressure regulator, the pressure is lower than the design pressure, and the sprayed oil is columnar, which is not suitable for mixing with air; When the pressure is too high, the sprayed oil is conical and difficult to mix. Moreover, the injection force is too large, and a lot of fuel is directly sprayed on the pipe wall, which directly affects the mixing ratio parameters.

If the oil outlet valve is well sealed, remove the side cover of the fuel injection pump, and check whether the locking screw of the sector gear is loose and displaced or the fuel injection quantity is too small. If there is no such phenomenon, remove the plunger coupling and check whether it is worn or not, even if the plunger is stuck in the sleeve and cannot move freely.

Extended data:

Working principle of automobile fuel injection quantity;

When the injector does not inject oil, the return spring tightly presses the needle valve on the valve seat through the armature to prevent oil dripping. When the electromagnetic coil is energized, it generates electromagnetic attraction, sucks up the armature and drives the needle valve to leave the valve seat. At the same time, the return spring is compressed, and the fuel is ejected from the annular gap between the shaft pin and the nozzle or orifice through the needle valve. When the electromagnetic coil is cut off, the electromagnetic attraction disappears. The port spring quickly closes the needle valve, and the injector stops injecting oil.

The fuel injector is mainly composed of a filter screen, a harness connector, an electromagnetic coil, a return spring, an armature and a needle valve, and the needle valve and the armature are made into a whole.