Hybrid Vehicle Mode Switching Under High-Speed Gear Limits
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Solution Overview
Problem
Existing hybrid electric vehicles face challenges in mode switching due to the limitations of the synchronizer, particularly at high speeds, leading to failed gear engagements and inability to switch to hybrid drive modes.
Innovation Solution
Implementing a method and device that include pre-gear operations and speed limits to manage mode switching by controlling the synchronizer and clutch, allowing mode transitions without excessive gear shifting, especially at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If gear shifting is performed at high vehicle speed, then mode switching may be achieved, but the synchronizer cannot complete the operation due to excessive speed difference
Solution Approach 1:
The control method performs preliminary actions by first switching to a suitable gear ratio before mode switching, and disengaging the clutch before engine start. This preliminary gear switching reduces the speed difference across the synchronizer to within acceptable limits, enabling reliable gear engagement even at high vehicle speeds.
Solution Approach 2:
The system dynamically adjusts the gear ratio selection based on real-time vehicle speed conditions. At high speeds, the control unit selects gear ratios that minimize synchronizer speed difference, while at lower speeds, normal gear switching procedures are used. This dynamic adaptation ensures reliable operation across the full speed range.
2Adaptability or versatility
If clutch engagement is performed during mode switching at high speed, then hybrid drive mode can be engaged, but the synchronizer speed difference exceeds operational limits
Solution Approach 1:
The control method performs preliminary gear switching to a suitable ratio before attempting mode switching, and disengages the clutch before engine start. This sequence of preliminary actions ensures that when the clutch is eventually engaged, the synchronizer speed difference is within operational limits, making the operation feasible.
Solution Approach 2:
The mode switching process is segmented into distinct phases: preliminary gear switching, clutch disengagement, engine start, and final mode engagement. This segmentation allows each sub-operation to be optimized independently, particularly enabling the synchronizer to operate within safe speed difference limits during critical engagement phases.
3Device complexity
If traditional mode switching control is used, then simple control logic is maintained, but mode switching fails at high vehicle speeds
Solution Approach 1:
The control unit continuously monitors vehicle speed and uses this feedback to dynamically adjust the mode switching strategy. When high vehicle speed is detected, the control logic automatically selects appropriate gear ratios and timing for clutch engagement to ensure successful mode switching, thereby maintaining reliability without requiring complex hardware modifications.
Data Source
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AI summary
The present disclosure relates to a method and a device for controlling mode switching of a hybrid electric vehicle, and a vehicle, and belongs to the field of hybrid electric vehicles. The method includes: performing, if the drive state information indicates that a current drive mode of the hybrid electric vehicle is a forward mode of a non-hybrid drive and in a case that a current speed reaches a speed limit, a pre-gear operation when a transmission gear of the hybrid electric vehicle is a neutral gear, to switch the transmission gear from the neutral gear to a second gear. The technical solution provided by the embodiments of the present disclosure can make the hybrid electric vehicle unable to switch to the hybrid drive mode due to the limitation of the ability of synchronizer on gear shifting when driving at a high speed.