Transmission Shift Control Under Load With Torque Transfer
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Solution Overview
Problem
Existing vehicle transmission control systems face challenges in efficiently shifting between transmission states, particularly when propulsion torque is applied, as they struggle to manage clutch engagement and motor speed coordination effectively.
Innovation Solution
A system and method for controlling vehicle transmission states by distributing propulsion torque to other drive systems, fully releasing the off-going clutch, controlling motor speed to match the target transmission state, and fully engaging the on-coming clutch to achieve seamless shifts between gear states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If clutch engagement and motor speed coordination are managed during propulsion torque application, then transmission shifting can occur under load, but clutch wear increases and shift smoothness deteriorates
Solution Approach 1:
The controller redistributes propulsion torque to other drive systems before fully engaging the on-coming clutch, preparing the system in advance to minimize clutch wear during the shifting operation
Solution Approach 2:
The controller acts as an intermediary by coordinating torque distribution across multiple drive systems, temporarily transferring load away from the shifting transmission to protect the clutch during engagement
2Reliability
If propulsion torque is redistributed to other drive systems during shifting, then clutch wear is reduced, but system complexity increases
Solution Approach 1:
The controller is designed to perform multiple functions: it manages both the shifting operation and the torque distribution across drive systems, eliminating the need for separate control systems and reducing overall system complexity
3Ease of operation
If motor speed is controlled to match target transmission state, then shift smoothness improves, but control complexity increases
Solution Approach 1:
The controller continuously monitors motor speed and adjusts it in real-time to match the target transmission state, using feedback control to ensure smooth shifting while managing control complexity through automated regulation
Data Source
AI summary
A system for controlling a transmission state of a vehicle includes a controller connected to a first drive system and a first transmission including a gear system, a first clutch and a second clutch. The controller is configured to receive a request to change from an initial transmission state to a target transmission state when a propulsion torque is applied to the vehicle. The controller is configured to distribute the propulsion torque such that all of the propulsion torque is applied by a second drive system and the first drive system does not provide any propulsion torque to the vehicle, fully release an off-going clutch from the gear system, control a motor speed based on a rotational speed relation of the target transmission state to reduce a slip speed of the on-going clutch, and fully engage an on-coming clutch to put the first drive system in the target transmission state.