The driver accelerates the accelerator pedal and accelerates the pedal position sensor to produce the corresponding voltage signal into the throttle control unit. The control unit first filters the input signal to eliminate the influence of the ambient noise. Then, the driver's intention is analyzed according to the current working mode, the pedal movement and the conversion rate, and the calculation is calculated. The basic requirements of engine torque are obtained, and the corresponding basic expectations of throttle angle are obtained. Then through the CAN bus and the vehicle control unit to communicate, get other working conditions information as well as all kinds of sensor signals, such as engine speed, gear position, throttle position, air conditioning energy consumption and so on, and then calculate all the torque required by the whole vehicle, and get the most throttle by compensating the watch value of the throttle angle. Good opening degree, and send the corresponding voltage signal to the driving circuit module, drive and control the motor to make the throttle reach the best opening position. The throttle position sensor returns the throttle opening signal to the throttle control unit to form a closed loop position control.

The throttle drive motor is usually a stepper motor or a DC motor, and the control modes are different. The H bridge circuit is often used to drive stepper motor. The control unit controls the stepper motor through the number of pulses, frequency and direction control level. The level of the level control the direction of the step motor rotation, the number of pulses to control the angle of the motor rotation, that is, a pulse signal is sent, the step motor turns a step angle, the pulse frequency controls the motor speed, and the speed is proportional to the pulse frequency. Therefore, by adjusting the above three parameters, the precise positioning and speed regulation of the motor can be realized.

The DC motor is controlled by pulse width modulation (PWM) technology, which has the characteristics of high frequency, high efficiency, high power density and high reliability. The control unit controls the rotation angle of the DC motor by adjusting the duty ratio of the pulse width modulation signal, and the direction of the motor is controlled by the reset spring connected to the throttle. The output torque of the motor is directly proportional to the duty cycle of the PWM signal. When the duty ratio is fixed, the opening of the throttle is constant when the motor output torque is balanced with the back spring resistance torque. When the duty ratio increases, the motor driving torque overcomes the back spring resistance moment, and the throttle opening increases. On the contrary, the motor output torque and throttle opening will decrease when the duty ratio is reduced.

ECU monitors the function of the system. If a fault is detected, the system fault light will be lit to indicate that the driver system is in trouble. At the same time, the electromagnetic clutch is separated, and the throttle valve is no longer controlled by the motor. The throttle returns to a small opening position under the action of the return spring to slow the vehicle to the maintenance site.