How to detect and evaluate the performance of Bosch Truck Injectors
For Bosch trucks, the performance of the injectors is related to the normal operation and operation of the engine and even the entire vehicle body. Therefore, when switching the injectors, the performance is high, the parameters are up to standard, and the adaptability is good. The assembly is very important. How to detect and evaluate the performance of Bosch truck injectors? Let's take a look together today:
Specifically, the performance testing and assessment of an injector need to start from the following aspects:
First, the injection volume is accurate
Adjust the amount of fuel injection in time according to the opening degree of the accelerator pedal. This is the basic principle of the electronic control system. In order to achieve a good state of the engine's power performance, emission performance, and comfort performance, there is a high demand for the accuracy of the injector's fuel injection under different operating conditions. Generally measured in mm3/stroke, which is one thousandth of a milliliter per injection.
Usually there are several ways to assess the accuracy of injection:
1) Static injection point
2) Dynamic injection curve
3) Spray repeatability, ie standard deviation
Second, the amount of leakage and functional return oil is normal
Leakage refers to the amount of oil that is leaked from the high pressure oil to the low pressure oil passage through the clearances of various mechanical components. Within the CRIN injector, there are six possible leak locations, as shown in the following figure.
Functional return oil refers to the amount of oil that the injector returns from the high pressure oil passage to the low pressure oil passage in order to achieve its own injection performance. It is mainly through the valve seat control chamber through the seat surface of the valve seat to the armature when the injector ball valve is opened. The amount of oil in the low pressure circuit around the unit. In the after-sales testing process, the return point (leakage + functional return) at the full load point is usually used as the assessment point.
Third, the jet delay is normal
Injection delay refers to the time interval from the start of energization of the electromagnet to the start of injection of the injector, typically between 300 and 800 microseconds. The level of the rail pressure, the performance of the electromagnet, the movement performance of each moving part, etc. will affect the size of the injection delay.
Fourth, the spray atomization effect is good
The atomization effect of fuel injection directly affects the combustion condition of diesel fuel and further affects the performance of the engine. The reason why high-pressure common rail systems use high-pressure injection is to achieve a good atomization effect. Therefore, the level of rail pressure directly affects the atomization effect. In addition, the shape of the nozzle nozzle and the surface condition of the nozzle wall surface have a significant influence on the atomization effect (such as mechanical damage to the nozzle orifice, cavitation erosion on the surface of the nozzle hole, wear of the particles, etc.).
From the performance of the Bosch truck injector mentioned above, it can be seen that the performance of the injector is closely related to each component. Failure or failure of any one component may cause the failure of the injector as a whole. In the course of maintenance, it is necessary to carry out systematic inspections of the inpidual parts of the fuel injectors one by one to find out the real cause of the failure, so as to eliminate them one by one and realize the maintenance effect and normal operation of the injector as soon as possible.