Hybrid Driveline Disconnect Clutch Boost Timing for Smooth Engagement
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Solution Overview
Problem
The driveline disconnect clutch in hybrid vehicles experiences delays in torque transfer due to the time required to remove space between clutch plates, which can lead to driveline torque disturbances and varying boost pressures influenced by factors like transmission fluid temperature, line pressure, and wear, affecting drivability and response time.
Innovation Solution
Adjusting the boost phase duration of the driveline disconnect clutch closing sequence in response to multiple error parameters, such as pressure and speed errors, to compensate for piece-to-piece variation, wear, and line pressure, thereby optimizing clutch engagement under various operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If boost pressure is applied to reduce clutch closing time, then driveline response time is improved, but driveline torque disturbances occur if boost pressure duration is not precisely controlled
Solution Approach 1:
The patent implements dynamic adjustment of the boost phase duration based on real-time operating conditions. The controller monitors parameters such as transmission fluid temperature, line pressure, and clutch wear state, then adaptively modifies the boost phase timing to achieve optimal clutch engagement. This dynamic control allows the system to reduce clutch closing time while preventing torque disturbances by adjusting boost duration to match actual operating conditions rather than using fixed timing.
Solution Approach 2:
The system incorporates feedback mechanisms where the controller continuously monitors clutch engagement performance and operating conditions. Based on this feedback, the controller adjusts the boost phase duration to compensate for variations in fluid temperature, pressure, and wear. This closed-loop control ensures that boost pressure is applied for the precise duration needed to reduce closing time without causing torque disturbances, as the system learns from actual engagement outcomes.
2Device complexity
If fixed boost phase timing is used, then control simplicity is maintained, but piece to piece variation and wear cause inconsistent clutch engagement
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the relationship between operating conditions (temperature, pressure, wear) and optimal boost phase duration. The controller is programmed with predetermined adjustment strategies based on monitored parameters, allowing it to proactively compensate for piece-to-piece variation and wear before they affect engagement consistency. This approach maintains reliability without requiring complex real-time calculations during clutch engagement.
3Device complexity
If transmission fluid temperature and line pressure variations are not compensated, then system simplicity is maintained, but boost timing becomes inconsistent
Solution Approach 1:
The patent implements parameter changes by monitoring transmission fluid temperature and line pressure, then adjusting the boost phase duration based on these parameters. When temperature or pressure deviates from nominal values, the controller modifies boost timing to compensate for the resulting variations in clutch engagement characteristics. This approach maintains precise boost timing across different operating conditions without requiring complex mechanical compensation mechanisms.
Data Source
AI summary
Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a time duration of a boost phase of a driveline disconnect clutch closing sequence is adjusted in response to one or more error values. The error values may include pressure error, integrated pressure error, and electric machine speed error.