Electrohydraulic Transmission Control with Integrated Blocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-speed automatic transmissions face challenges in ensuring safe and reliable operation across varying conditions, with existing control systems often requiring additional space and complexity to implement blocking features that prevent undesirable operating modes and failures.
Innovation Solution
The electrohydraulic control system incorporates a pressure control subassembly and shift valve subassembly with fluid connections that block or enable control of torque transmitting mechanisms based on pressure switch activation, preventing engagement during unsafe conditions and reducing the number of valves and fluid passages, thus conserving space and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocking features are added to prevent undesirable operating modes, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines blocking features with existing electro-hydraulic control components by integrating fluid connections between shift valves and pressure control valves. This merging approach allows blocking functionality to be achieved without adding separate, independent blocking mechanisms, thereby improving reliability while minimizing increases in device complexity.
Solution Approach 2:
The electro-hydraulic control components are designed to perform multiple functions: normal shift control and blocking of undesirable modes. By making these components multi-functional, the patent avoids adding dedicated blocking components, thus improving reliability without proportionally increasing device complexity.
2Object-affected harmful factors
If blocking features are added to prevent undesirable operating modes, then safety is improved, but device complexity increases
Solution Approach 1:
The patent merges blocking functionality into the existing electro-hydraulic control architecture by using fluid connections between shift valves and pressure control valves. This integration allows safety improvements through blocking features without requiring separate, complex blocking systems.
Solution Approach 2:
The patent uses hydraulic fluid as an intermediary medium to transmit blocking signals from shift valves to pressure control valves. This intermediary approach allows safe blocking of undesirable modes through the existing hydraulic system rather than requiring direct mechanical or electrical blocking mechanisms.
3Reliability
If additional valves and fluid passages are added for blocking features, then reliability is improved, but the transmission assembly size increases
Solution Approach 1:
The patent combines blocking functionality with existing electro-hydraulic control components by integrating fluid connections between shift valves and pressure control valves. This merging approach allows blocking functionality to be achieved without adding separate, independent blocking mechanisms, thereby improving reliability while minimizing increases in device complexity.
4Object-affected harmful factors
If fluid connections are configured to block control when pressure switch is not activated, then safety is improved, but device complexity increases
Solution Approach 1:
The fluid connection system automatically blocks control signals when the pressure switch is not activated, without requiring external control logic or additional actuators. The hydraulic circuit itself provides the blocking function through its configuration, allowing safety improvements while minimizing increases in device 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
This solution provides safer and more reliable shifting by preventing undesirable torque transmitting mechanism engagement, reducing the complexity and size of the transmission assembly, while maintaining limp home capabilities and efficient clutch control across different operating modes.
Implementation Method 1
a first fluid connection directly connecting the first electrohydraulic actuator with the first pressure switch
Data Source
AI summary
A control for a multi-speed automatic vehicle transmission is provided. Electrical and hydraulic components are provided, including pressure control or “trim” valve systems in fluid communication with shift valves and electrohydraulic actuators to selectively engage and disengage the transmission clutches or other shift mechanisms. Pressure switches are provided for the trim valves and shift valves. The fluid connections between the trim valve systems and the shift valve systems are configured to reduce the total number of valves and fluid passages required and to reduce the size of at least one of the valves. Clutch blocking features are provided. Power off limp home and reduced engine load at stop features are provided in all forward ranges, and control of double transition shifts is also provided.