Vacuum failure auxiliary brake control system for electric vehicle

Abstract

According to a vacuum failure auxiliary brake control system for an electric vehicle, the vacuum degree pressure value and the vacuum degree pressure value decreasing rate of a vacuum degree sensor are monitored in real time through a central controller, the fault level is judged according to the vacuum degree pressure value and the vacuum degree pressure value decreasing rate, and under the condition that a brake lamp switch is not triggered, in a certain data acquisition period, if the vacuum degree pressure value decline rate is greater than a set value 1, judging that the fault is a vacuum system air leakage first-level fault; in a certain data acquisition period, if the vacuum degree pressure value decline rate is greater than a set value 2, judging that the fault is a vacuum system air leakage secondary fault; and when the vacuum degree pressure value is smaller than the set value 4, the central controller judges that the vacuum system leakage three-level fault occurs, the central controller enters the state of preparing to start the vacuum failure auxiliary braking function, and meanwhile, a braking system fault lamp is turned on, a sound alarm is generated, and a fault code is recorded. According to the system, under the condition that the vacuum booster system fails, through logic setting of the central controller, the ESC and the motor driving system are cooperated to carry out braking and quit braking according to the intention of a driver, so that the driving safety is ensured.

Description

technical field [0001] The invention relates to the control technology of the electric vehicle system, in particular to the vacuum failure auxiliary braking control technology of the electric vehicle. Background technique [0002] Under the background of energy crisis and environmental problems, electric vehicles (including pure electric, plug-in hybrid or extended range, etc.) have become the development trend of our country and the world. The biggest difference between electric vehicles and traditional fuel vehicles in the braking system is the source of the brake booster capability. The vacuum degree of the common brake booster of electric vehicles comes from the electronic vacuum pump to extract vacuum to obtain vacuum booster. The common brake booster of fuel vehicles The vacuum degree comes from the vacuum boost obtained by pumping the vacuum when the engine is running. Therefore, for electric vehicles, it is very important for the electronic vacuum pump to extract va...

AI Technical Summary

Problems solved by technology

[0003] Chinese patent document CN110775039A discloses a method of vacuum control logic based on electric vehicle braking safety. This method does not classify different vacuum degree value drop rates and absolute values ​​and adopts corresponding working logic. , after only judging the brake pedal signal and vehicle speed, it sends a braking request signal to the ESC. There is a loophole in this starting condition, and there is a braking behavior of the ESC that exceeds the driver's expectations, which has potential safety hazards.

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