Shift-By-Wire Park Lock Control Using Motor Rotation Limiting
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Solution Overview
Problem
The electric shift-by-wire system faces issues where structural defects, such as misalignment of the detent plate, can cause unintended release of the P stage, leading to safety risks and battery discharge due to continuous monitoring and potential vehicle rolling.
Innovation Solution
A controlling apparatus and method that utilize a shift stage sensor and position sensor to detect the target shift stage and limit motor rotation when the P stage is likely to be released, employing 2-phase energization for a switched reluctance motor to prevent unintended P stage release, and outputting a failure signal after a predetermined period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous monitoring and motor rotation limiting control is implemented to prevent unintended P stage release, then safety is improved, but battery discharge increases due to continuous control operations
Solution Approach 1:
The control operation is performed periodically only within a predetermined time period after P stage engagement, rather than continuously. The controller executes the rotation limiting control at specific intervals (when shift to P is completed and within the time window), allowing the system to maintain safety while reducing energy consumption during extended idle periods.
Solution Approach 2:
The controller starts the monitoring and control operation in advance when the shift to P stage is completed, establishing a predetermined time window for active control. This preliminary action ensures safety coverage is activated exactly when needed (immediately after engagement) and automatically deactivates after the time period expires, preventing unnecessary continuous operation.
2Reliability
If the controller limits motor rotation by applying 2-phase energization to prevent P stage release, then reliability is improved, but device complexity increases
Solution Approach 1:
The controller changes the electrical parameter state of the motor by applying 2-phase energization instead of normal operation modes. This parameter change (switching specific phases) creates a magnetic field that prevents rotor rotation, achieving reliable P stage stability through electrical control rather than mechanical constraints.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents unintended release of the P stage, thereby preventing safety accidents and reducing battery discharge by limiting motor rotation within a predetermined period after P stage engagement, while identifying shift stage failures.
Implementation Method 1
the controller may limit the rotation of the motor by applying 2-phase energization to the motor
Data Source
AI summary
A controlling apparatus for an electric shift-by-wire system is disclosed. The apparatus includes a shift stage sensor detecting information on a target shift stage according to the operation of the shift lever; a position sensor detecting information on a position of the motor; and a controller configured to receive the detected information from the shift stage sensor and the position sensor, when the target shift stage is a P stage, determine whether the P stage is likely to be released using the position information of the motor, and when it is determined that the P stage is likely to be released, limit rotation of the motor.