Electro-Hydraulic Control System for Automatic Transmission
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Solution Overview
Problem
Current automatic transmissions with solenoid and regulator valve systems are bulky, costly, and suffer from hydraulic response time delays and temperature sensitivity, leading to reduced fuel economy due to excessive valve layers and variable displacement pump controls.
Innovation Solution
A reduced-layer electro-hydraulic control system using solenoid-actuated valves to connect pressure sources to hydraulic lines for Drive and Reverse positions, eliminating the regulator valve and reducing the number of valves, allowing for faster gear shifts and improved packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional valve body assembly with multiple layers and regulator valves is used, then the system can control clutches and brakes, but the valve body size and cost increase significantly
Solution Approach 1:
The patent removes the regulator valve from the hydraulic control system, eliminating the multi-stage hydraulic control path. This extraction simplifies the valve body structure, reducing the number of layers from four to two, and decreases valve body height by approximately 30 mm while maintaining adequate control of clutches and brakes through direct solenoid-actuated valve control.
Solution Approach 2:
The patent integrates the functions of multiple valves into a reduced number of solenoid-actuated valves. By merging control functions and eliminating redundant components like the regulator valve, the system achieves the same control reliability with a more compact valve body structure containing only two layers instead of four.
2Manufacturing precision
If multiple regulator and latch valves are used for independent clutch and brake control, then control precision is improved, but hydraulic response time delays increase
Solution Approach 1:
The patent eliminates the regulator valve and its associated multi-stage hydraulic control path. This removal reduces the number of hydraulic stages from multiple stages to a direct solenoid-actuated valve to clutch/brake path, thereby reducing hydraulic response time delays while maintaining control precision through direct electronic control.
3Adaptability or versatility
If conventional variable displacement pump control is used, then pump output can be adjusted, but system stability deteriorates and fuel economy decreases
Solution Approach 1:
The patent implements electronic feedback control through solenoid-actuated valves that directly control hydraulic pressure to clutches and brakes. This electronic feedback system replaces indirect mechanical pump control, improving system stability by providing precise, responsive control while maintaining adaptability through electronic control signals that can be dynamically adjusted based on transmission operating conditions.
4Manufacturing precision
If bleed flows are used to improve hydraulic control performance, then control repeatability is improved, but fuel economy deteriorates due to hydraulic power loss
Solution Approach 1:
The patent eliminates the need for bleed flows by removing the regulator valve and its associated hydraulic control path. This extraction eliminates the continuous hydraulic power loss associated with bleed flows while maintaining control repeatability through direct solenoid-actuated valve control that provides precise, on-demand hydraulic pressure control without continuous energy dissipation.
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
The system reduces valve body height, shortens gear shift time, and lowers costs by minimizing valve count, resulting in enhanced fuel economy and reduced size.
Implementation Method 1
A first solenoid-actuated valve may be connected between the pressure source and a first control element, such as a clutch or a brake
Data Source
AI summary
A system for controlling a transmission includes a gear selector, a manual valve for connecting a pressure source alternately to Drive and Reverse lines in response to movement of the gear selector between selected Drive and Reverse positions, first and second solenoid-actuated valves, the first valve connecting the pressure source to a first control element, the second valve connecting the Reverse line to a second control element when the Reverse position is selected, a third solenoid-actuated valve connecting the Drive line to a third control element when the Drive position is selected, and a control valve through which pressure in the first control element is vented when the Drive position is selected.