Compensator Circuit Restriction for Transmission Pressure Retention
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Solution Overview
Problem
Automotive transmissions with complex gear sets and electronic control systems face issues with fluid pressure loss due to leaks and wear, leading to potential transmission failure during critical functions like low-RPM hot reverse engagements, where fluid flow is not properly regulated.
Innovation Solution
Installation of a redesigned compensator valve and a restrictor device within the transmission to limit fluid flow, ensuring line supply pressure is maintained by controlling fluid flow through the compensator circuit, using a cylindrical body with specific coaxial members and lands to restrict fluid flow, and a restrictor plug to further regulate fluid flow, thereby preventing pressure loss during critical functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fluid flow through the compensator circuit is unrestricted, then the compensator valve can operate smoothly, but line supply pressure is lost during critical functions
Solution Approach 1:
A restrictor device is introduced as an intermediary component in the compensator circuit to mediate between the need for smooth compensator valve operation and the need to maintain line supply pressure. The restrictor limits fluid flow through the compensator circuit, preventing pressure loss while still allowing the compensator valve to function properly.
Solution Approach 2:
The restrictor device changes the flow parameters in the compensator circuit by introducing a controlled restriction. This modifies the fluid flow characteristics to achieve the desired balance between compensator valve operation and line pressure maintenance.
2Adaptability or versatility
If the transmission system uses complex gear sets and electronic control, then greater gear ratios and precise control are achieved, but fluid pressure loss due to leaks and wear increases
Solution Approach 1:
The restrictor device provides beforehand cushioning by pre-limiting fluid flow through the compensator circuit. This preventive measure ensures that even when leaks and wear occur in the complex transmission system, line supply pressure is preserved during critical functions, maintaining reliability.
3Object-generated harmful factors
If the compensator circuit is allowed to drain down, then air intrusion is reduced, but clutch engagement becomes delayed during downshifts
Solution Approach 1:
The restrictor device acts as an intermediary that controls the drainage rate of the compensator circuit. By limiting fluid flow, it prevents rapid draining that would cause air intrusion while also preventing complete drainage that would delay clutch engagement, thus mediating between these two opposing requirements.
Data Source
AI summary
A system and method for an automotive transmission includes one or more restrictor devices that are installed within a valve body of the automotive transmission to improve performance by establishing a flow limit along the compensator circuit. The complex fluid circuits of certain automotive transmissions having eight to ten speeds allow line pressure supply to bleed out during certain critical functions, such as low rotations per minute hot engagements, which can severely damage the transmission. By limiting flow, the line pressure supply can be preserved to prevent the compensator circuit from bleeding out in these critical functions. The instant invention limits flow by replacing the standard compensator valve with a compensator valve that has a larger spool diameter. Flow is further reduce by another restriction device placed along the compensator circuit between the compensator valve and the clutch drums.