Vehicle Transmission Park System Actuation Control
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Solution Overview
Problem
Existing electronically actuated transmission park systems in vehicles risk damage when actuated at high speeds due to reliance on a single speed sensor, which may provide inaccurate or faulty speed data, leading to improper engagement of the park mode.
Innovation Solution
The method employs multiple independent speed sensors to determine the lowest vehicle speed, ensuring accurate determination of whether the vehicle is at or below the maximum allowable actuation speed before actuating the transmission park system, thereby preventing damage and ensuring safe and robust engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single speed sensor is used to control the transmission park system, then the device complexity is reduced, but the reliability of speed measurement deteriorates due to potential inaccurate or faulty readings
Solution Approach 1:
The patent applies local quality by using multiple speed sensors positioned at different locations in the transmission system (input shaft speed sensor and output shaft speed sensor). Each sensor provides localized speed measurements that are then compared to determine the lowest valid speed, ensuring accurate park system actuation decisions without requiring a single complex high-precision sensor
Solution Approach 2:
The patent implements beforehand cushioning by using multiple redundant speed sensors to anticipate and prevent faulty readings before they cause damage. The system compares readings from multiple sensors and uses the lowest valid reading, providing a safety buffer against inaccurate measurements that could lead to improper park system engagement at high speeds
2Ease of operation
If the transmission park system is actuated at high speeds, then the ease of operation is improved, but the transmission park system damage risk increases
Solution Approach 1:
The patent applies feedback by continuously monitoring vehicle speed through multiple speed sensors and using this information to control park system actuation. The transmission control unit receives speed data, compares it against safe actuation thresholds, and only permits park engagement when the lowest sensed speed is below the maximum allowable speed, preventing high-speed damage while maintaining operational simplicity
Solution Approach 2:
The patent implements preliminary anti-action by preventing park system actuation when speed readings indicate the vehicle is moving above the maximum allowable speed. The control unit proactively blocks the actuation signal before high-speed engagement can occur, eliminating the harmful effect before it can damage the transmission park system
Data Source
AI summary
A method of controlling a transmission of a vehicle equipped with an electronic transmission range select system includes receiving an electronic request to actuate a transmission park system. A speed of the vehicle is sensed with each of a plurality of different speed sensors to define a plurality of different sensed vehicle speeds. Each of the plurality of different speed sensors provides a sensed vehicle speed that is independent and separate from the sensed vehicle speed from all of the other speed sensors. All of the different sensed vehicle speeds from the plurality of speed sensors is compared to each other to determine the lowest sensed vehicle speed. When the lowest sensed vehicle speed is equal to or less than a maximum allowable actuation speed, an electronic signal is sent from the transmission control unit to the transmission park system to actuate the transmission park system.