Hybrid Powertrain Engine Start Control with Adaptive Disconnect Clutch
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Solution Overview
Problem
Existing vehicle powertrain control systems face challenges in efficiently starting the engine under varying conditions, particularly with the disconnect clutch, which affects drivability and fuel efficiency, especially during transitions between engine and electric machine operation.
Innovation Solution
A controller is programmed to adaptively learn and manage the disconnect clutch engagements based on previous experiences, adjusting the clutch's torque capacity and starter motor operation across different conditions, including non-stroked and zero torque, stroked and zero torque, non-stroked and non-zero torque, and stroked and non-zero torque scenarios, to optimize engine starting processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the disconnect clutch is closed to start the engine under all conditions, then the fuel efficiency is improved, but the reliability of engine starting deteriorates under certain clutch conditions
Solution Approach 1:
The controller monitors clutch parameters (stroked condition and torque) and changes the starting method based on parameter thresholds. When parameters indicate unsafe conditions (stroked clutch with non-zero torque), the system switches from clutch-based starting to starter motor starting, ensuring reliability while maintaining fuel efficiency during safe conditions
Solution Approach 2:
The system continuously monitors clutch status and provides feedback to the controller, which adjusts the starting strategy in real-time. This feedback mechanism allows the system to learn from previous engagements and adapt to varying clutch conditions, resolving the contradiction between fuel efficiency and starting reliability
2Reliability
If the starter motor is used to start the engine under all conditions, then the reliability of engine starting is improved, but the fuel efficiency deteriorates
Solution Approach 1:
The system changes the starting method based on monitored parameters. When clutch conditions are favorable (non-stroked or stroked with zero torque), the system uses clutch-based starting for fuel efficiency. When parameters indicate unsafe conditions, it switches to starter motor starting for reliability
Solution Approach 2:
The system uses the starter motor only partially or selectively under specific conditions rather than continuously. This partial action approach maintains reliability when needed while avoiding unnecessary energy consumption during conditions where clutch-based starting is sufficient
3Productivity
If the disconnect clutch engagement is aggressive, then the productivity of engine starting is improved, but the wear on clutch components increases
Solution Approach 1:
The system applies cushioning by monitoring clutch conditions before engagement and using starter motor starting as a protective measure when conditions indicate potential damage risk. This beforehand protection prevents harmful wear while maintaining efficient starting when conditions are favorable
Solution Approach 2:
The adaptive learning system uses feedback from previous clutch engagements to adjust future engagement strategies. By learning from past experiences, the system optimizes engagement timing and force to balance starting speed with wear reduction
Data Source
AI summary
A vehicle includes an engine, an electric machine, a disconnect clutch, a starter motor, and a controller. The engine and electric machine are each configured to generate power to propel the vehicle. The disconnect clutch is disposed between the engine and the electric machine. The controller is programmed to, in response to a command to start the engine, operate either the disconnect clutch or the starter motor to start the engine based on a level of adaptive learning of previous disconnect clutch engagements.