Hybrid Vehicle Clutch Control for Torque Shock Mitigation
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Solution Overview
Problem
Hybrid vehicles experience torque shock when switching driving modes due to significant differences in maximum driving forces between the engine and motor, leading to an uncomfortable driving experience.
Innovation Solution
A clutch control device that uses a control unit to select a smaller battery output based on state of charge and temperature maps, and sets a change vehicle velocity to minimize the difference between motor and engine driving forces, ensuring smooth transitions between driving modes by managing the engagement and release of the clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the clutch is engaged to transmit engine driving force to the motor shaft, then the vehicle can be driven in parallel driving mode with enhanced power, but a torque shock occurs when switching from parallel driving mode to series/EV driving mode due to large difference between engine and motor driving forces
Solution Approach 1:
The control unit determines a change vehicle velocity in advance based on battery output characteristics before mode switching occurs. By pre-calculating the optimal switching point where engine and motor driving forces are balanced, the system prepares for smooth transition beforehand, preventing torque shock when the clutch disengages from engaged to released state
Solution Approach 2:
The control unit dynamically adjusts the change vehicle velocity parameter based on real-time battery state of charge and temperature conditions. By modifying this critical parameter according to battery output capabilities, the system ensures that mode transitions occur at velocities where driving force differences between engine and motor are minimized, thereby eliminating torque shock
2Use of energy by moving object
If the clutch is released to allow motor-driven EV or series driving mode, then the vehicle can operate with electric power, but a torque shock occurs when switching to parallel driving mode due to large difference between motor and engine driving forces
Solution Approach 1:
The control unit pre-determines the change vehicle velocity based on battery output characteristics before the vehicle transitions from motor-driven mode to engine-driven parallel mode. This preliminary calculation identifies the optimal velocity point where engine and motor driving forces are balanced, allowing smooth clutch engagement without torque shock
Solution Approach 2:
The control unit dynamically modifies the change vehicle velocity parameter according to battery state of charge and temperature. By adjusting this parameter to match battery output capabilities, the system ensures transitions occur at velocities where the difference between motor and engine driving forces is minimized, preventing torque shock during mode switching
3Device complexity
If the battery output is not considered in mode switching, then the control system is simpler, but a large difference between engine and motor driving forces causes torque shock and uncomfortable driving experience
Solution Approach 1:
The control unit dynamically adjusts the change vehicle velocity parameter based on battery state of charge and temperature conditions. By modifying this critical parameter according to battery output capabilities, the system ensures mode transitions occur at velocities where driving force differences are minimized, eliminating torque shock without requiring complex additional hardware
Solution Approach 2:
The control unit continuously monitors battery state of charge and temperature, using this feedback to dynamically determine the appropriate change vehicle velocity. This closed-loop control ensures that mode switching always occurs at optimal points where engine and motor driving forces are balanced, preventing torque shock while adapting to real-time battery conditions
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A hybrid vehicle (10) includes: a battery (13) which is charged with electricity generated by a generator (12); a motor (15) which drives a motor shaft that is connected with a driving shaft of the hybrid vehicle (10) by using at least one of the electricity generated by the generator (12) and the electricity charged in the battery (13); an engine (11) which drives the generator (12) and the hybrid vehicle (10); a clutch (16); and a control unit (23) which acquires a possible battery output that can be outputted by the battery (13) and which sets a change vehicle velocity depending on the possible battery output, the control unit (23) which changes an engaged state of the clutch (16) in which the motor shaft and an engine shaft of the engine (11) are engaged with each other to a released state of the clutch (16) in which the motor shaft and the engine shaft are released from each other and changes an engine driving state of the hybrid vehicle (10) in which the hybrid vehicle (10) is driven by the engine (11) to a motor driving state of the hybrid vehicle (10) in which the hybrid vehicle (10) is driven by the motor (15), when a vehicle velocity of the hybrid vehicle (10) is the change vehicle velocity.