Hybrid Vehicle Input Clutch Control for Resonance Prevention
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Solution Overview
Problem
Hybrid vehicles face difficulties in engine startability when the starting clutch is in a released state due to resonance issues in the drive system, which can lead to inefficient engine starting and increased noise and vibration (NV) due to the drag torque generated by a wet starting clutch in the power transmission path.
Innovation Solution
A control apparatus is implemented in the hybrid vehicle to manage the engine-start control operation by switching the input clutch to an engaged state until the engine rotational speed exceeds a predetermined speed value, then switching it back to a released state, thereby managing the resonance rotational speed of the drive system to prevent resonance and improve startability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the starting clutch is in a released state to allow engine starting, then engine startability is improved, but resonance occurs in the drive system causing difficult engine start and increased noise and vibration
Solution Approach 1:
The control apparatus engages the input clutch before engine starting to prevent resonance, then disengages it after the engine starts. This preliminary action of engaging the clutch before the harmful resonance condition occurs prevents the resonance problem while maintaining engine startability.
Solution Approach 2:
The system dynamically switches the state of the input clutch based on the engine operating condition. The clutch is engaged during the starting phase to avoid resonance, then disengaged after starting completes, allowing the system to adapt its configuration to different operational states and eliminate resonance harmful effects.
2Object-affected harmful factors
If the input clutch is engaged during engine starting, then resonance is prevented, but the complexity of the control operation increases
Solution Approach 1:
The control apparatus combines the control of the input clutch with the existing engine starting control logic. By integrating the clutch state management into the overall engine starting sequence, the system prevents resonance without requiring a separate independent control system, thus reducing overall complexity.
Solution Approach 2:
The control apparatus uses feedback from the engine starting process to automatically manage the input clutch state. The system monitors engine starting conditions and automatically engages or disengages the clutch accordingly, eliminating the need for complex manual control while preventing resonance.
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 enhances engine startability by preventing the engine rotational speed from passing through resonance zones, reducing noise and vibration, and ensuring smoother engine starting even when the starting clutch is in a released state.
Implementation Method 1
a damper disposed between the engine and the connecting/disconnecting clutch in the power transmission path
Implementation Method 2
the resonance rotational speed of a drive system including the damper
Implementation Method 3
a wet starting clutch disposed between the electric motor and the automatic transmission in the power transmission path
Data Source
AI summary
A hybrid vehicle includes a connecting/disconnecting clutch disposed between an engine and an electric motor, an automatic transmission including an input clutch, a starting clutch disposed between the electric motor and the automatic transmission, and a control apparatus for executing an engine-start control operation for starting the engine, by igniting the engine after increasing a rotational speed of the engine by a torque of the electric motor while placing the connecting/disconnecting clutch into an engaged state. In process of the engine-start control operation that is executed when the hybrid vehicle is in a stopped state with the starting clutch being in a released state, the control apparatus places the input clutch in an engaged state until the rotational speed of the engine exceeds a predetermined speed value, and switches the input clutch to a released state after the rotational speed of the engine has exceeded the predetermined speed value.