Automatic Parking Lock Engagement Logic for Vehicle Safety
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Solution Overview
Problem
Existing automatic and automated motor vehicle transmissions lack a method to automatically engage the parking lock that balances vehicle safety against unintended start-up or rolling while minimizing disruptions to vehicle drivability and avoiding surprising changes in the vehicle's operating state.
Innovation Solution
The method involves five variations of automatically engaging the parking lock based on the driver's selected drive position and vehicle parameters, using Boolean logical operators to combine individual functional connections, ensuring the parking lock is engaged only when necessary to prevent unintended movement while allowing for maximum vehicle availability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the parking lock is automatically engaged when ignition is interrupted and vehicle speed is low, then vehicle safety against unintended rolling is improved, but vehicle drivability is impaired due to unexpected engagement
Solution Approach 1:
The system dynamically adjusts the automatic parking lock engagement behavior based on the selected drive position. When neutral position is selected, automatic engagement is enabled for safety. When drive positions are selected, automatic engagement is disabled to maintain drivability. This dynamic adaptation resolves the contradiction between safety and ease of operation.
Solution Approach 2:
The system changes the engagement parameter (automatic parking lock activation) based on the drive position parameter. By monitoring whether neutral or drive position is selected, the system adjusts the automatic engagement behavior accordingly, allowing safety-critical scenarios to be protected while preserving normal driving operations.
2Reliability
If the transmission automatically switches to neutral position when ignition is closed and motor is not running, then vehicle safety is improved, but unexpected change in operating state surprises the driver
Solution Approach 1:
The system performs preliminary action by automatically engaging the parking lock before the driver might manually operate the vehicle. This prevents unintended rolling or movement from occurring, addressing safety concerns proactively while the drive position context ensures the action is appropriate and not surprising to the driver.
3Reliability
If automatic parking lock engagement is implemented without considering drive position, then safety protection is improved, but device complexity increases due to additional control logic
Solution Approach 1:
The existing drive position selection mechanism is utilized for dual purposes: normal driving control and safety-critical automatic parking lock engagement control. By making the safety function universal with the existing control interface, no additional complex control logic or separate systems are required, maintaining simplicity while achieving comprehensive safety protection.
Data Source
AI summary
A method of automatically engaging a parking lock of an automatic or automated transmission of a motor vehicle, which can be engaged by way of a selector device depending on a drive position selected by the driver of the motor vehicle and depending on other operating parameters. In order to achieve as little restriction of the drivability of the motor vehicle as possible, without neglecting the safety of the driver and the surroundings, five different variation of an Auto-P function are proposed for automatically engaging the parking lock: two of these variations are associated with an electrically interrupted ignition circuit of the motor vehicle; two variations are associated with an electrically closed ignition circuit and a simultaneously stopped vehicle drive motor and one variations is associated with an electrically closed ignition circuit and a simultaneously operating drive motor.