Vehicle Drive Control Device Torque Shock Suppression
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Solution Overview
Problem
Existing control devices for vehicle drive systems with rotary electric machines and friction engagement devices experience torque differences when transitioning from slip engagement to direct engagement, causing shocks and discomfort for occupants due to errors in torque capacity and output torque.
Innovation Solution
A control device that regulates hydraulic pressure to maintain a target rotational state of the rotary electric machine, allowing smooth torque transfer from the internal combustion engine to the wheels by controlling the first and second friction engagement devices, and adjusts hydraulic pressure to the second friction engagement device based on output torque during state transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first friction engagement device is controlled to a predetermined transfer torque capacity to be brought into the slip engagement state, then the internal combustion engine can be started using torque of the rotary electric machine, but a torque difference may be caused when the second friction engagement device is brought from the slip engagement state into the direct engagement state, causing shock to occupants
Solution Approach 1:
The control device executes rotational state control to establish a target rotational state of the rotary electric machine before the second friction engagement device transitions to direct engagement. This preliminary action ensures that the rotary electric machine is ready to compensate for torque differences, preventing shock to occupants when the torque state changes.
Solution Approach 2:
The control device continuously monitors the actual torque of the rotary electric machine and compares it with the maximum torque. Based on this feedback, it dynamically adjusts the target transfer torque capacity of the second friction engagement device, ensuring smooth transition and preventing torque differences that would cause shock.
2Speed
If rotational speed feedback control is executed to make the rotational speed of the rotary electric machine coincide with target rotational speed, then the speed change mechanism can operate smoothly, but torque fluctuations occur due to error in transfer torque capacity of the second friction engagement device
Solution Approach 1:
The control device uses dual feedback mechanisms: rotational speed feedback control to maintain speed precision, and torque feedback control to monitor actual torque against maximum torque. This combined feedback approach allows the system to adjust the target transfer torque capacity dynamically, eliminating torque fluctuations while maintaining speed control precision.
Solution Approach 2:
The control device changes the target transfer torque capacity parameter of the second friction engagement device based on the torque deviation amount. By dynamically adjusting this parameter according to actual torque conditions, the system maintains both speed control precision and torque stability.
3Power
If the second friction engagement device is controlled to transfer predetermined torque in a slip engagement state, then torque can be transferred to the wheels, but torque fluctuations occur when transitioning to direct engagement state
Solution Approach 1:
The control device dynamically adjusts the target transfer torque capacity of the second friction engagement device based on the torque deviation amount and rotational speed difference. This dynamic control ensures smooth transition from slip engagement to direct engagement, maintaining torque stability while preserving torque transfer capability throughout the process.
Solution Approach 2:
The control device changes the target transfer torque capacity parameter according to the torque deviation amount. This parameter adjustment allows the second friction engagement device to transfer torque smoothly during slip engagement and transition stably to direct engagement without torque fluctuations.
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 solution effectively suppresses torque differences during state transitions, ensuring a smooth and comfortable driving experience by gradually adjusting torque and reducing the impact of errors in torque capacity and output torque.
Implementation Method 1
a second friction engagement device is provided between the rotary electric machine and the wheels
Implementation Method 2
hydraulic pressure supplied to the second friction engagement device in the slip engagement state is controlled on the basis of torque of the rotary electric machine
Data Source
AI summary
The present invention relates to a control device that controls a vehicle drive device in which a rotary electric machine is provided in a power transfer path that connects between an internal combustion engine and wheels and in which a first friction engagement device is provided between the internal combustion engine and the rotary electric machine and a second friction engagement device is provided between the rotary electric machine and the wheels.