Vehicle Drive Control Device Torque Gap Suppression
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Solution Overview
Problem
Existing vehicle drive control devices experience torque gaps when transitioning from slip engagement to direct engagement states due to errors in transfer torque capacity or output torque, leading to uncomfortable shocks for occupants.
Innovation Solution
A control device that regulates hydraulic pressure to the second friction engagement device based on the rotary electric machine's torque during rotational state control, ensuring a smooth transition by adjusting the target torque and rotational speed feedback control to match the predetermined torque after the first friction engagement device transitions to direct engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rotational speed feedback control is executed only during slip engagement state, then control simplicity is maintained, but torque gaps occur during transition to direct engagement state causing shocks
Solution Approach 1:
The control device calculates a preliminary target transfer torque capacity for the second friction engagement device based on the difference between actual and target rotational speeds of the rotary electric machine, even before the transition to direct engagement state. This preliminary calculation ensures that when the second friction engagement device transitions to direct engagement, the torque is already optimized to prevent gaps and shocks, rather than waiting until the transition occurs.
Solution Approach 2:
The control device continuously monitors the actual rotational speed of the rotary electric machine and compares it with the target rotational speed. Based on this feedback, the control device dynamically adjusts the target transfer torque capacity of the second friction engagement device. This feedback mechanism ensures that torque optimization is maintained throughout the transition process, preventing torque gaps that would cause shocks to occupants.
2Stability of the object's composition
If target transfer torque capacity is optimized during slip engagement, then torque transfer smoothness is improved, but control is not effective after direct engagement state is reached
Solution Approach 1:
The control device continues to execute rotational speed feedback control and calculate target transfer torque capacity throughout the entire transition process from slip engagement to direct engagement state, rather than stopping control when direct engagement is reached. This continuous control ensures that torque optimization is maintained without interruption, preventing torque gaps and ensuring smooth torque transfer throughout the entire engagement process.
Solution Approach 2:
The control device prepares the target transfer torque capacity in advance during the slip engagement state, calculating the optimal torque value based on rotational speed differences. This preliminary preparation ensures that when the transition to direct engagement occurs, the torque is already optimized, maintaining smooth torque transfer and preventing shocks to occupants.
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 effectively suppresses torque gaps during state transitions, enhancing the smoothness of vehicle operation and reducing the likelihood of shocks felt by occupants.
Implementation Method 1
hydraulic pressure supplied to the second friction engagement device is controlled on the basis of torque of the rotary electric machine produced during the rotational state control
Data Source
AI summary
A control device that controls a vehicle drive device, including a rotary electric machine and internal combustion engine that drive wheels, a first friction engagement device and a second friction engagement device. The control device is configured to execute rotational state control in which a rotational state of the rotary electric machine is controlled so as to establish a target rotational state with the second friction engagement device in a slip engagement state, and hydraulic pressure regulation control in which a hydraulic pressure supplied to the second friction engagement device is controlled on the basis of torque of the rotary electric machine produced during the rotational state control after the first friction engagement device is transitioned to a direct engagement state while the second friction engagement device is transitioned from the slip engagement state to a direct engagement state.