Control method for starting up automatic transmission only at P/N gear

Abstract

A control method for starting up an automatic transmission only at a P / N gear comprises the steps of: acquiring a P / N gear signal of a gearshift handle through an automatic transmission control unit (TCU); directly controlling to a start relay through a rigid line by the TCU for a vehicle which is not configured with a passive entry passive start system (PEPS); controlling the start relay sequentially through the rigid line and the passive entry passive start system by the automatic TCU for the vehicle which is configured with the passive entry passive start system; monitoring a fault of the rigid line at any time and sending a fault signal to an engine control unit (ECU) through a controller area network (CAN) by the TCU; judging whether to start up an engine in the gear state and selecting whether to receive the fault signal of the rigid line by the ECU. According to the control method for starting up the automatic transmission only at the P / N gear, the TCU monitors the rigid line in real time and sends the fault signal of the rigid line to the ECU through the CAN, and the ECU judges whether to receive the fault signal, so that a double-protection function is achieved.

Description

technical field [0001] The invention belongs to the technical field of automobile automatic transmission control systems, and relates to a control method for starting P and N gears of AT and DCT vehicles. technical background [0002] Such as image 3 The shown prior art automatic transmission is all to have TCU to pass hard wire ( image 3 middle STLK hard line) direct control, TCU in the figure monitors the shifting signal at all times, when shifted to P, N, the triode in the TCU conducts, and outputs low level to the start relay 2, at this time, move the ignition key to ignite When the switch is turned to the start position, the start relay 1 and 2 form a high-low voltage difference, the start relay pulls in, and the starter motor is started; when the gear is shifted to D and R, the starter motor should not be started. At this time, the triode in the TCU is cut off, input the signal of stopping the starting motor (high level) at the starting relay 2, and disconnect the st...

AI Technical Summary

Problems solved by technology

When the STLK hard wire is short-circuited to the ground, the triode circuit in the TCU is short-circuited, and the TCU sends a signal to the start relay to start the motor (low-frequency pull-in relay). At this time, the shift is in the D and R positions. Continue to turn, the vehicle will move forward or backward, which will cause harm to personal property

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