A fuel injection control circuit and a fuel injection control method

Abstract

The present invention provides a fuel injection control circuit and a fuel injection control method. By arranging a first isolation circuit and a second isolation circuit in the fuel injection control circuit, the first isolation circuit and the second isolation circuit control the fuel injector There is only one isolation circuit in which the drive voltage is input to the input terminal of the high-side drive circuit connected to the isolation circuit, thereby cutting off the return path of the current and preventing the current from flowing into the first high-side drive circuit and the second high-side drive circuit. There is no end where the high-side drive circuit that controls the work of the fuel injector is located, which avoids waveform distortion of the working current of the fuel injector.

Description

technical field [0001] The invention belongs to the field of fuel injectors, and more specifically relates to a fuel injection control circuit and a fuel injection control method. Background technique [0002] At present, the fuel injection control circuit of the fuel injector has redundant functions to improve the reliability of the engine. The circuit diagram of the fuel injection control circuit is as follows figure 1 As shown, the fuel injection control circuit includes: a first high-side drive circuit, a first low-side drive circuit, a second high-side drive circuit and a second low-side drive circuit, a first high-side drive circuit and a first low-side drive circuit Corresponding to ECU1 in the two ECUs (Electronic Control Unit, electronic control unit) used to control the engine, the second high-side drive circuit and the second low-side drive circuit correspond to ECU2 in the two ECUs used to control the engine, so that ECU1 and ECU2 control the fuel injector throu...

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Problems solved by technology

[0003] exist figure 1 The output ends of the first high-side drive circuit and the second high-side drive circuit are connected to the first end of the injector (also called the high-side of the injector), the first low-side drive circuit and the second low-side drive circuit The input end of the drive circuit is connected to the second end of the injector (also called the low side of the injector) through a diode, so that when ECU1 (the main ECU at this time) controls the injector, the current direction is: The input terminal of the first high-side driving circuit is connected to the driving voltage ( figure 1 Marked as BOOST), the current flows from the first high side drive circuit through the first end of the injector to the injector, and then from the second end of the injector to the first low side drive circuit, from the first low The side drive circuit flows back to BOOST, but since the first low-side drive circuit and the second low-side drive circuit are both connected to the second end of the injector, and the first high-side drive circuit and the second high-side drive circuit are connected to the same BOOST, so when ECU1 controls the injector, the current may flow to the second low-side drive circuit, and finally flow to ECU2 (standby ECU, the path flowing to ECU2 is called the return path), resulting in distortion of the current waveform of ECU1

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