Electronic Transmission Range Selection Hydraulic Control
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Solution Overview
Problem
Existing hydraulic control systems for automatic transmissions lack improved efficiency, responsiveness, and smoothness, necessitating a cost-effective and advanced configuration.
Innovation Solution
A hydraulic control system incorporating a pressure regulator subsystem, clutch control subsystem, and an electro-hydraulic circuit with mode valves and solenoids to manage pressurized hydraulic fluid for selective engagement of torque transmitting devices, including a park mechanism with a park sensor assembly for precise transmission range selection and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a traditional mechanical shifting cable system is used, then the connection between driver interface and transmission is reliable, but the instrument panel space is reduced and styling options are limited
Solution Approach 1:
The patent replaces the mechanical shifting cable system with an electronic transmission range selection (ETRS) system that uses electronic signals and a hydraulic control mechanism. The ETRS system eliminates the physical cable connection between the driver interface and transmission, substituting it with an electronic signal path that controls hydraulic valves to engage park mechanisms, thereby freeing up instrument panel space and enabling greater styling flexibility.
Solution Approach 2:
The patent extracts and removes the mechanical cable system from the vehicle interior, eliminating the need for cable routing through the instrument panel. This extraction of the mechanical connection allows for increased instrument panel space and design freedom while maintaining the essential function of transmission range selection through an electronic-hydraulic alternative.
2Adaptability or versatility
If an ETRS system is implemented, then instrument panel space increases and styling options are enhanced, but the hydraulic control system requires improved efficiency and responsiveness
Solution Approach 1:
The patent segments the hydraulic control system into distinct functional modules: a pressure regulator subsystem that provides pressurized hydraulic fluid, mode valves (first and second) that direct fluid flow to different circuits, and a park mechanism with a park feed valve. This segmentation allows each component to be optimized for its specific function, improving overall system efficiency and responsiveness while maintaining reliability.
Solution Approach 2:
The patent incorporates a park lock control device that is dynamically actuatable to mechanically prevent the park mechanism from engaging during engine stop-start events. This dynamic control element allows the system to adapt to different operating conditions, ensuring reliable operation by preventing park engagement when the engine is restarting, thereby enhancing overall system reliability.
3Measurement precision
If the park mechanism is designed for precise control, then transmission range selection accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent introduces a park sensor assembly as an intermediary element that detects whether the park mechanism is engaged. This sensor provides feedback to the control system, enabling precise determination of transmission range selection. The sensor acts as a mediator between the mechanical park mechanism and the electronic control system, ensuring accurate range detection without requiring complex mechanical feedback mechanisms.
4Adaptability or versatility
If multiple torque transmitting devices are used, then the transmission can provide multiple speed ratios, but the control system becomes more complex
Solution Approach 1:
The patent designs the hydraulic control system with universal components that can manage multiple torque transmitting devices. The pressure regulator subsystem provides pressurized fluid to multiple circuits, and the mode valves are configured to direct this fluid to different torque transmitting devices based on the selected range. This multi-functional design allows a single hydraulic control architecture to manage multiple speed ratios and transmission modes without proportionally increasing system complexity.
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
Enhances transmission efficiency, responsiveness, and smoothness by enabling precise control of torque transmitting devices and park mechanism operation, improving overall transmission performance.
Implementation Method 1
The mode valves are supplied with fluid via one or more solenoid valves or other valves
Implementation Method 2
A hydraulic control system includes a source of pressurized hydraulic fluid that communicates with a discrete electronic transmission range selection (ETRS) subsystem
Data Source
AI summary
A hydraulic control system for a transmission is provided. The hydraulic control system includes a source of pressurized hydraulic fluid that communicates with a discrete electronic transmission range selection (ETRS) subsystem. The hydraulic control system includes first and second mode valves located downstream of a hydraulic fluid pressure source. The mode valves are supplied with fluid via one or more solenoid valves or other valves. The mode valves have a plurality of ports configured to transfer pressurized hydraulic fluid. The first mode valve transfers pressurized hydraulic fluid from the source to the second mode valve. The second mode valve transfers pressurized hydraulic fluid from the first mode valve to one of drive or reverse. An electro-hydraulic circuit for pulling the transmission out of park and putting the transmission into park is also provided. A park sensor assembly including a Hall Effect sensor switch is also provided.