Nonlinear Clutch Torque Exchange for Smoother Gear Shifts
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Solution Overview
Problem
The smoothness of gear shifting in vehicles, particularly in hybrid vehicles, is not adequately addressed by existing technologies, leading to potential torque surges and impacts on drivability.
Innovation Solution
A gear shifting control method that involves nonlinearly adjusting the gear shifting torques allocated to the offgoing and oncoming clutches during the torque exchange phase to adapt to the response characteristics of the torque control system, thereby improving the smoothness of the gear shifting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear torque allocation is used during gear shifting, then the control system is simple, but torque surges occur and smoothness deteriorates
Solution Approach 1:
The patent applies parameter changes by transitioning from linear torque allocation to nonlinear torque allocation during the torque exchange phase. The torque allocation follows a nonlinear function that adapts to the dynamic characteristics of the clutch hydraulic system, thereby suppressing torque surges and improving shifting smoothness without significantly increasing control system complexity
Solution Approach 2:
The patent implements dynamics by making the torque allocation strategy adaptive rather than static. The control system dynamically adjusts the torque distribution between offgoing and oncoming clutches based on the real-time state of the torque exchange phase, using nonlinear functions that respond to system characteristics and improve smoothness
2Object-affected harmful factors
If torque exchange duration is extended, then smoothness improves, but shifting time increases
Solution Approach 1:
The patent changes the torque allocation parameters from linear to nonlinear functions during the torque exchange phase. This allows for optimized torque distribution that suppresses torque surges and improves smoothness within a controlled time frame, balancing smoothness improvement with acceptable shifting duration
Solution Approach 2:
The control system monitors the torque exchange process and adjusts torque allocation based on system response characteristics. The nonlinear torque allocation function incorporates feedback about the clutch hydraulic system's response behavior to optimize the balance between smoothness and shifting time
Data Source
AI summary
A gear shifting control method includes: determining a torque exchange duration and a total clutch request torque T0 in a torque exchange phase; within the torque exchange duration, gradually decreasing a gear shifting torque Toff allocated to an offgoing clutch, and gradually increasing a gear shifting torque Ton allocated to an oncoming clutch, where it is satisfied that Toff+Ton=T0; where Ton and Toff are set to change nonlinearly within the torque exchange duration to suppress an impact of a response speed change of a torque control system on smoothness of a torque exchange. Embodiments also include a vehicle controller, a vehicle, and a storage medium.