Vehicle Drive Control Device Slip Engagement Strategy
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Solution Overview
Problem
Existing vehicle drive control devices face challenges in ensuring comfortable traveling performance when both internal combustion engine start control and shift control are executed simultaneously, particularly due to issues with rotational speed management and torque transfer, leading to potential termination of shift control and compromised vehicle comfort.
Innovation Solution
A control device that includes a start control section for engaging the disconnecting engagement device, a start slip control section for managing shift engagement devices, and an intended engagement device deciding section that selects the appropriate shift engagement device based on vehicle speed and set determination speeds to maintain smooth control and prevent immediate termination of shift control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the internal combustion engine start control and shift control are executed simultaneously, then the engine can be started and the vehicle can accelerate, but the rotational speed management becomes complex and may cause immediate termination of shift control
Solution Approach 1:
The control device determines the appropriate shift engagement device to be slipped in advance before executing simultaneous start control and shift control. By pre-determining which engagement device should be slipped based on the target shift speed, the system avoids complex real-time rotational speed management issues and ensures smooth execution of both controls without immediate termination of shift control.
2Power
If the rotational speed of the input-side rotating member increases with internal combustion engine start control, then the engine starts, but the shift control may be immediately terminated causing uncomfortable traveling performance
Solution Approach 1:
The control device uses a slip engaged state as an intermediary condition between disengaged and fully engaged states. By bringing the determined shift engagement device into a slip engaged state during simultaneous start control and shift control, the system acts as a buffer that absorbs the rotational speed mismatch, allowing smooth torque transfer and preventing immediate termination of shift control, thereby ensuring comfortable traveling performance.
3Speed
If the shift engagement device is slipped to manage rotational speed, then the shift control can continue, but the torque transfer to wheels may become unstable
Solution Approach 1:
The control device applies slip control only to the specific shift engagement device that is determined to be appropriate based on the target shift speed, while other engagement devices maintain their normal engagement states. This localized application of slip control allows rotational speed synchronization at the critical point without affecting the overall torque transfer stability to the wheels.
Data Source
AI summary
A control device for a vehicle drive device. A start control section executes internal combustion engine start control. A start slip control section executes start slip control of bringing one of the plurality of shift engagement devices into a slip engaged state. An intended engagement device deciding section that decides as an intended engagement device, based on a set determination speed. The intended engagement device deciding section decides as the intended engagement device a special engagement device that is the shift engagement device having been in the direct-coupling engaged state in order to form the reference shift speed, and that is disengaged when a transition is made to a special shift speed on an opposite side of the specific shift speed from the reference shift speed in order of speed ratios of the plurality of shift speeds.