Lockup Clutch On-Coming Capacity Detection via Dynamic Model
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Solution Overview
Problem
Current systems fail to accurately detect when a lockup clutch in torque converters is transmitting a discernable amount of torque, which is crucial for efficient engagement and operation between internal combustion engines and automatic transmissions.
Innovation Solution
A method and system that involve retrieving a dynamic model defining torque transmitted by the lockup clutch based on operating parameters, asserting a lockup clutch command, monitoring these parameters, and continually solving the model to determine torque transmission, producing a lockup clutch on-coming capacity signal if the torque exceeds a threshold, using sensors and a control circuit to compute angular acceleration and rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a lockup clutch is engaged in a torque converter, then torque transmission between engine and transmission is improved, but the ability to accurately detect when the clutch is transmitting discernable torque deteriorates
Solution Approach 1:
The patent introduces an intermediary detection system that uses sensors to monitor pump and turbine speeds, along with a control circuit that processes these signals to compute angular acceleration and solve the dynamic model. This intermediary system enables accurate detection of lockup clutch torque transmission without directly measuring the clutch itself, resolving the contradiction between maintaining torque transmission and achieving detection accuracy.
Solution Approach 2:
The patent replaces direct mechanical measurement of clutch torque with a computational approach. Instead of using complex mechanical torque sensors on the clutch, the system substitutes a dynamic model that calculates torque transmission based on monitored operating parameters (pump speed, turbine speed, angular acceleration), achieving accurate detection through mathematical computation rather than direct mechanical measurement.
2Measurement precision
If a dynamic model with multiple operating parameters is used to detect lockup clutch torque, then detection accuracy is improved, but system complexity increases
Solution Approach 1:
The control circuit performs multiple functions: it receives pump speed signals from the pump speed sensor, receives turbine speed signals from the turbine speed sensor, computes angular acceleration, retrieves the dynamic model, solves the model to determine torque transmission, and generates control signals. This multi-functional approach consolidates what would otherwise be separate systems into a single control unit, improving detection accuracy while managing system complexity through functional integration.
Data Source
AI summary
A dynamic model is stored in memory that defines torque transmitted by a lockup clutch in a torque converter as a function of a plurality of torque converter operating parameters. A lockup clutch command to control engagement the lockup clutch is asserted, and thereafter a number of the plurality of torque converter operating parameters are monitored. The model is continually solved using the monitored operating parameters to determine torque transmitted by the lockup clutch over time, and a lockup clutch on-coming capacity signal is produced if the torque transmitted by the lockup clutch exceeds a torque threshold.