Shift-By-Wire Parking Lock Release Using Motor Torque Correction
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Solution Overview
Problem
Existing vehicle shift systems require a large and costly actuator to release the parking lock mechanism when switching from the parking range to a non-parking range, especially when the vehicle is parked on a slope, due to the increased torque required.
Innovation Solution
A control apparatus that includes an electric motor, a lock mechanism, and an actuator apparatus, which performs torque correction control to reduce the load on the lock mechanism by adjusting the output torque of the electric motor when switching from the parking range to a non-parking range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional actuator is used to release the parking lock mechanism when switching from parking range to non-parking range, then the lock can be released, but the actuator requires large size and high cost especially when parked on a slope
Solution Approach 1:
The control apparatus performs preliminary torque correction by the electric motor before the actuator releases the parking lock mechanism. When the shift lever is operated from parking range to non-parking range, the control apparatus corrects the output torque of the electric motor to reduce the load on the lock mechanism before actuation, enabling a smaller actuator to suffice
Solution Approach 2:
The electric motor acts as an intermediary to reduce the load on the parking lock mechanism before the actuator operates. By correcting the motor torque in advance, the system creates favorable conditions for the actuator to release the lock with reduced force requirements
2Reliability
If a conventional actuator is used to release the parking lock mechanism when switching from parking range to non-parking range, then the lock can be released, but the actuator requires high cost
Solution Approach 1:
The control apparatus performs preliminary torque correction by the electric motor before the actuator releases the parking lock mechanism. When the shift lever is operated from parking range to non-parking range, the control apparatus corrects the output torque of the electric motor to reduce the load on the lock mechanism before actuation, enabling a smaller actuator to suffice
Solution Approach 2:
The electric motor acts as an intermediary to reduce the load on the parking lock mechanism before the actuator operates. By correcting the motor torque in advance, the system creates favorable conditions for the actuator to release the lock with reduced force requirements
Data Source
AI summary
A control apparatus is mountable to a vehicle including an electric motor, a lock mechanism, and an actuator apparatus. The control apparatus controls the electric motor and a shift-by-wire system provided in the vehicle. The shift-by-wire system performs switching to shift ranges of the vehicle including a shift range and a non-parking range other than the parking range. The control apparatus drives the actuator apparatus to release the lock on the power transmission mechanism by the lock mechanism based on the shift range of the shift-by-wire system being switched from the parking range to the non-parking range. The control apparatus performs torque correction control in which an output torque of the electric motor is corrected such that a load acting on the lock mechanism from the power transmission mechanism is reduced based on the shift range of the shift-by-wire system being switched from the parking range to the non-parking range.