Electronic Shift Lever Fail-Safe Control via Override Cable
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fail-safe systems for vehicles with electronic shift lever units face instability and unexpected conditions due to TCU failures, often requiring costly component additions or design changes to implement effective fail-safe mechanisms.
Innovation Solution
A method using an electronic shift lever unit to communicate with the TCU, verify failure states, and forcibly release the parking insertion by pulling an override cable, thereby implementing fail-safe operations without additional components or design changes, utilizing CAN BUS or serial communication for rapid verification and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fail-safe system is implemented using the transmission itself, then the parking insertion can be forcibly released, but the system becomes unstable and may create unexpected conditions due to the transmission state
Solution Approach 1:
The electronic shift lever unit serves as an intermediary between the driver and the transmission system. It independently verifies TCU failure states through communication and executes fail-safe operations by controlling the override cable, rather than relying directly on the transmission system itself. This intermediary approach isolates the fail-safe function from transmission instability.
Solution Approach 2:
The fail-safe function is segmented from the transmission control system and relocated to the electronic shift lever unit. The shift lever unit independently performs TCU failure verification and executes parking release operations, creating a separate control pathway that does not depend on the transmission's operational state.
2Reliability
If additional components are added to implement fail-safe, then the fail-safe function can be improved, but the cost and design complexity increase
Solution Approach 1:
The electronic shift lever unit is designed to perform multiple functions: normal shift control, TCU failure verification through communication, and fail-safe execution by controlling the override cable. This multi-functionality eliminates the need for dedicated fail-safe components while maintaining reliable fail-safe operation.
Solution Approach 2:
The electronic shift lever unit uses its own existing components (motor, communication interface, control logic) to verify TCU failure states and execute fail-safe operations. The system serves itself by utilizing the shift lever unit's inherent capabilities rather than requiring external fail-safe mechanisms.
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
This approach enables rapid and accurate fail-safe implementation with higher control stability, informing drivers of excessive speed and ensuring safe parking states without increasing costs or altering the vehicle design.
Implementation Method 1
driving a motor of a parking power machine in order to pull an override cable connected to a parking sprag locked in a parking gear of the transmission to unlock the parking sprag from the parking gear
Data Source
AI summary
The present invention relates to a method for controlling a TCU fail-safe using an electronic shift lever. A failure state of TCU is verified through CAN BUS (serial communication, or hardware wire) using an electronic shift lever unit, and a parking sprag is forcibly unlocked from a parking gear by pulling an override cable for parking by the an electronic shift lever unit when TCU being in the failure state, so that the implementation of fail-safe according to a failure of TCU is accomplished with higher control stability than using a transmission and without an addition of a component or a change of design.