Hybrid Vehicle Controller Clutch Engagement for Torque Shock Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid vehicles, when switching from a mode where the engine is stopped to a mode where the engine is operating, the existing methods fail to timely reduce torque transmission shock due to differences in motor and engine rotation speeds, leading to incomplete shock reduction.
Innovation Solution
A controller for hybrid vehicles that restarts the engine in a first start mode with the clutch non-fully engaged when the motor rotation speed is higher than a determination value and in a second start mode with the clutch fully engaged when the motor rotation speed is lower, allowing for smoother transitions between travel modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the clutch is engaged and the engine is restarted using the motor's power, then the vehicle can switch from electric-only mode to engine mode, but torque transmission shock occurs when the engine rotation speed exceeds the motor rotation speed
Solution Approach 1:
The controller determines in advance whether to engage the clutch fully or partially before engine restart based on the motor rotation speed. When motor rotation speed is below the determination value, the clutch is engaged fully before combustion starts, preventing the engine speed from exceeding motor speed and causing shock. This preliminary decision based on predicted conditions resolves the contradiction by preventing the harmful effect before it occurs.
Solution Approach 2:
The controller changes the clutch engagement parameter (fully engaged vs. partially engaged) based on the motor rotation speed parameter. By adjusting the clutch engagement state according to the motor speed condition, the system adapts the torque transmission characteristics to prevent shock while enabling mode switching. This parameter-based adaptation resolves the contradiction between mode switching capability and shock prevention.
2Object-affected harmful factors
If the clutch is engaged fully before engine restart, then torque transmission shock is prevented, but the engine may not start smoothly when motor rotation speed is high
Solution Approach 1:
The controller dynamically changes the clutch engagement parameter based on the motor rotation speed. When motor speed is below the determination value, full engagement is applied to prevent shock. When motor speed is above the determination value, partial engagement is used to ensure smooth engine start. This conditional parameter adjustment resolves the contradiction by adapting the engagement strategy to the specific operating conditions.
Solution Approach 2:
The controller performs preliminary assessment of the motor rotation speed and determines the appropriate clutch engagement strategy before engine restart. This advance decision ensures that the clutch is in the optimal engagement state for the current motor speed, preventing both shock and start failures. The preliminary action based on predicted outcomes resolves the contradiction between shock prevention and start reliability.
3Object-affected harmful factors
If the clutch engagement is delayed to match engine and motor rotation speeds, then shock is reduced, but the transition time between travel modes increases
Solution Approach 1:
The controller changes the clutch engagement parameter (full vs. partial) based on motor rotation speed to achieve rapid mode switching without excessive shock reduction delays. By using partial engagement when appropriate, the system achieves both quick response and acceptable shock levels, resolving the time-shock contradiction.
Solution Approach 2:
The controller makes a preliminary determination of the optimal clutch engagement strategy based on current motor speed, enabling immediate action without waiting for speed synchronization. This advance decision eliminates the time delay associated with waiting for speed matching while still preventing excessive shock through appropriate engagement control.
4Object-affected harmful factors
If the clutch is engaged partially with the engine stopped, then shock is reduced during engagement, but combustion cannot be started smoothly
Solution Approach 1:
The controller performs preliminary assessment of motor rotation speed and determines the appropriate clutch engagement state before initiating combustion. This advance decision ensures that the clutch is in the optimal engagement state for the current conditions, preventing both shock and combustion start failures. The preliminary action resolves the contradiction by ensuring the right engagement state is established before combustion begins.
Solution Approach 2:
The controller dynamically changes the clutch engagement parameter based on motor rotation speed conditions. By adjusting the engagement state according to speed conditions, the system ensures both smooth combustion start and acceptable shock levels. This parameter adaptation resolves the contradiction between combustion reliability and shock reduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces torque transmission shock and maintains exhaust purification efficiency by selecting the appropriate start mode based on motor rotation speed, ensuring timely clutch engagement and minimizing idle periods.
Implementation Method 1
a motor arranged on a power transmission path between an engine and a wheel
Implementation Method 2
a clutch arranged on a portion of the power transmission path between the engine and the motor
Implementation Method 3
starting combustion in the engine
Data Source
AI summary
Upon a request for switching from a first travel mode of traveling with a clutch disengaged and operation of an engine stopped to a second travel mode of traveling with the clutch engaged and the engine operating, a controller for a hybrid vehicle restarts the engine in the following manner. That is, the controller restarts the engine in a first start mode of starting combustion in the engine with the clutch non-fully engaged when a rotation speed of a motor is greater than a determination value and restarts the engine in a second start mode of starting combustion in the engine with the clutch fully engaged when the rotation speed of the motor is less than or equal to the determination value.