Hydraulic Control Device for Automatic Transmission Torque Assist
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Solution Overview
Problem
The complexity of control logic in hydraulic control systems for automatic transmissions increases with multiple types of motor assists, requiring intricate management of switching patterns for torque assist levels, leading to potential complications in belt slipping or clutch slipping.
Innovation Solution
A hydraulic control device that unifies the levels of commanded hydraulic pressure across different torque assist requests, simplifying the control logic by treating multiple switching patterns as a single torque assist request, and using a torque assist coordination control unit to maintain uniform hydraulic pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of motor assists are implemented with different switching patterns, then torque assist performance is improved, but control logic complexity increases
Solution Approach 1:
The patent merges multiple switching patterns (zero→small, zero→large, small→large) into a unified control logic that treats all torque assist requests uniformly. The transmission controller consolidates the hydraulic control strategies for different assist types, using a single control flow that determines hydraulic pressure based on current and target torque values without distinguishing between different switching pattern types.
Solution Approach 2:
The control system implements a universal torque assist coordination control logic that handles all types of torque assist requests (small and large assists) through the same control pathway. This universal control strategy eliminates the need for separate control branches for different assist types, thereby simplifying the overall control logic while maintaining the ability to provide multiple levels of torque assistance.
2Adaptability or versatility
If multiple switching patterns are used for torque assist levels, then assist control flexibility is improved, but hydraulic control complexity increases
Solution Approach 1:
The patent combines the hydraulic control strategies for different torque assist levels into a unified control approach. Instead of maintaining separate hydraulic control circuits for small and large assists, the system uses a single hydraulic control pathway that adjusts line pressure and pulley pressures based on the torque assist request, thereby simplifying hydraulic control complexity while preserving assist control flexibility.
3Measurement precision
If complex control logic is implemented for multiple assist types, then torque assist precision is improved, but responsiveness decreases
Solution Approach 1:
The control system performs preliminary determination of torque values (current torque and target torque) and calculates the required torque assist in advance. By pre-calculating the hydraulic pressure requirements based on torque values before the actual torque assist execution, the system reduces the computational burden during real-time operation, thereby improving responsiveness while maintaining precise torque assist control.
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 approach simplifies the control logic for transmission hydraulic control, enhances responsiveness, and effectively suppresses slipping of hydraulically operated members, ensuring consistent torque assist performance across various assist levels.
Implementation Method 1
a transmission controller configured to unify levels of the commanded hydraulic pressure when control that increases the commanded hydraulic pressure is carried out
Data Source
AI summary
As a driving source, an engine and an assist motor are provided. An engine control module includes a torque assist control unit for controlling the assist motor by a plurality of types of switching patterns having different torque assist levels. A CVT control unit includes a torque assist coordination control unit that, when a torque assist request is input from the torque assist control unit, carries out the control that increases commanded hydraulic pressure so as to increase the hydraulic pressure of hydraulically operated members. When carrying out the control that increases the commanded hydraulic pressure, the torque assist coordination control unit unifies the levels of the commanded hydraulic pressure regardless of the types of the switching patterns.