Transmission Park State Detection via Pivotable Member Actuator
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Solution Overview
Problem
Shift-by-wire transmissions in vehicles lack a practical mechanism to shift out of PARK without the engine running, making it difficult to tow the vehicle or roll it to a new location, and existing override solutions are complex, difficult to access, and prone to mechanical issues due to exposure to environmental debris.
Innovation Solution
A diagnostic system with a pivotable member and actuator that generates diagnostic signals based on the shiftable member's position, allowing for override functionality and vehicle control, including engaging the parking brake or limiting vehicle operation, to facilitate shifting out of PARK without engine power, using a combination of actuators, sensors, and a controller to manage the parking pawl and friction elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If shift-by-wire transmission eliminates mechanical connection between control device and transmission, then transmission control precision and automation are improved, but ease of operation for shifting out of PARK without engine running deteriorates
Solution Approach 1:
A pivotable member acts as an intermediary mechanical element that the driver can directly manipulate to override the electronic park lock. This member mechanically engages with the parking pawl through the actuator, providing a direct physical interface for shifting out of PARK without requiring engine power, thus resolving the contradiction between automation and ease of operation.
Solution Approach 2:
The patent replaces the traditional continuous mechanical connection with an electronic control system (shift-by-wire). The control device transmits electrical signals to electronic controllers that direct actuators to apply or release friction elements, eliminating the need for a direct mechanical linkage between the gear selector and transmission components.
2Ease of operation
If complex override mechanisms are added to enable shifting out of PARK without engine, then ease of operation is improved, but device complexity and reliability deteriorate
Solution Approach 1:
The override mechanism is merged with the existing actuator assembly. The pivotable member integrates with the actuator that already exists in the shift-by-wire system, combining the override functionality with the existing mechanical components rather than adding a separate, complex external mechanism. This reduces overall device complexity while maintaining ease of operation.
3Ease of operation
If override mechanism is made accessible to driver, then ease of operation is improved, but exposure to environmental debris and mechanical issues increases
Solution Approach 1:
The pivotable member and override mechanism are nested within the protected environment of the transmission housing and actuator assembly. The driver accesses the override through the existing gear selector lever interface, which is already protected from environmental debris. The critical mechanical components remain enclosed within the transmission case, shielding them from dust, moisture, and other harmful environmental factors.
4Measurement precision
If diagnostic system monitors pivotable member position continuously, then measurement precision is improved, but use of energy and system complexity increase
Solution Approach 1:
The pivotable member's position detection leverages the existing mechanical structure and actuator feedback systems already present in the shift-by-wire transmission. The controller utilizes signals from the actuator's position sensors and the mechanical state of the pivotable member itself, rather than requiring additional dedicated diagnostic sensors and power sources. This self-service approach maintains high measurement precision while minimizing additional energy consumption.
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
Enables safe and accessible shifting out of PARK without the engine, providing diagnostic alerts and controlling vehicle operations to ensure safe towing or movement, while maintaining system reliability and simplicity by using an integrated override mechanism within the transmission assembly.
Implementation Method 1
a biasing spring configured to exert a biasing torque on the pivotable member to bias the pivotable member toward the first side of the notch
Data Source
AI summary
A transmission diagnostic system includes a pivotable member and an actuator. The actuator has a notch with a first side, a second side, and an opening between the two sides. The width of the opening is greater than a width of the pivotable member. The pivotable member is retained within the notch, and the actuator is configured to selectively pivot the pivotable member between an engaged position, corresponding to a PARK gear, and a disengaged position, corresponding to a gear other than PARK. The transmission diagnostic system also includes a biasing spring configured to exert a biasing torque on the pivotable member to bias the pivotable member toward the first side of the notch. The transmission diagnostic system further includes a controller configured to generate at least one diagnostic signal in response to the pivotable member not being in contact with the first side of the notch.