Electric vehicle creep torque control method and control system and electric vehicle

Abstract

The invention discloses a control method and a control system for a worming torque of an electric automobile. The control method comprises the following steps: acquiring a basic part T1 of the worming torque according to a vehicle speed u look-up table; calculating a gravity acceleration component a3 of a vehicle according to a longitudinal acceleration a1 and a travel acceleration a2 of the vehicle; calculating a gradient resistance compensation part initial value T2' of the worming torque according to a complete vehicle mass m, the gravity acceleration component a3 and a tire rolling radius R; attenuating the obtained gradient resistance compensation part initial value T2' of the worming torque with increase of the vehicle speed according to a current vehicle speed u, thereby obtaining a gradient resistance compensation part T2 of the worming torque; adding the basic part T1 of the worming torque with the gradient resistance compensation part T2 of the worming torque to obtain a total worming torque T; and controlling a driving motor to output the total worming torque T to enable the vehicle to worm. The control method and the control system take a road grade into consideration to achieve compensation of gradient resistance, thereby enabling the vehicle to have same acceleration performance and good comfort no matter traveling uphill, downhill or on a level road.

Description

technical field [0001] The invention relates to the technical field of automobile control, in particular to an electric automobile creep torque control method and control system. Background technique [0002] At present, vehicles generally have a creep function. When the vehicle is not pulled on the handbrake, the vehicle is put into forward gear or reverse gear, and the vehicle will creep slowly when the brake pedal is released (the accelerator is not stepped on). [0003] The creep control function of traditional automobiles is usually realized by the automatic transmission controller. Since the engine has a minimum idle speed limit, the creep control function needs to include torque control and differential speed control. The automatic transmission controller is controlled by clutch slip friction (applicable to DCT / AMT type automatic transmission) or hydraulic torque converter coupling degree control (applicable to AT / CVT type automatic transmission) to realize creep cont...

AI Technical Summary

Problems solved by technology

[0004] For electric vehicles, since the driving motor has no minimum speed limit, and many of the matched transmissions do not have clutches, the creep control method of traditional vehicles is no longer applicable.

[0005] At present, the vehicle creep control simply obtains the current creep torque through the vehicle speed lookup table. Since the road gradient is not taken into account, the creep performance on flat roads is good, but there is no creep or slip on slopes. If the calibration is adjusted so that the creep performance on the slope is good, the creeping acceleration on the flat road will be too high and the comfort will be poor.

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