Rail pressure pre-control system based on hardware constant-current control and control method

Abstract

The invention relates to a rail pressure pre-control system based on hardware constant-current control and a control method. The system comprises an ECU (electronic control unit) internal timing interruption module, a reference current inquiry module, a current distribution module, a constant-current drive pulse width capturing and calculation module and a PWM (pulse width modulation) drive pulse width calculation module; timing interruption is triggered under effects of the ECU internal timing unit; the reference current inquiring module is used for calculating the reference current of a measurement unit; the current distribution module is used for dividing the reference current into a current regulating value and a current setting value and transmitting the current regulating value and the current setting value; the constant-current drive pulse width capturing and calculation module is used for capturing constant-current drive pulses, calculating the width of the constant-current drive pulses, and simultaneously transmitting calculation results to the PWM drive pulse width calculation module; and the PWM drive pulse width calculation module is used for calculating the drive pulse width of a PWM drive unit and transmitting calculation results to the PWM drive unit. In the method, ECU internal timing interruption produced by a timer in an ECU and external interruption produced by the triggering edge of the constant-current drive pulses are implemented in operation of main programs of ECU control. Accurate control and high response speed can be achieved, the difficulty and the complexity in software control can be reduced simultaneously, and hardware resources of processors can be saved.

Description

technical field [0001] The invention relates to a rail pressure pre-control algorithm. In particular, it relates to a rail pressure pre-control system and control method based on hardware constant current control of a common rail engine fuel injection system based on constant current control. Background technique [0002] Usually the rail pressure control logic mainly includes the following parts: actual rail pressure measurement and filtering, rail pressure control target value calculation, rail pressure controller PID design, rail pressure control state machine design, rail pressure control actuator output control, etc. The basic idea is: according to the actual measurement of the rail pressure value through a suitable filter algorithm as the feedback value of the closed-loop control; calculate the rail pressure control deviation as the PID input, and the output of the controller determines the output flow of the high-pressure oil pump, which is similar to the high-pressur...

AI Technical Summary

Problems solved by technology

The current closed-loop control mode based on the software method is always difficult to quickly and accurately follow the target current

[0006] Because the temperature of the control valve environment changes greatly, the ambient temperature of the control valve varies greatly from the start-up process to the high-load work process, the actual control valve resistance always deviates from the set standard resistance, and the deviation value is always fluctuating, which will inevitably affect different The performance of the rail pressure controller in the working environment

At the same time, the software closed-loop control method has a long response cycle due to the limitation of processor interrupt delay and computing power, and the response of current following control is also slow, so that the rail voltage pre-control cannot achieve the best effect

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