Hybrid Vehicle Control Unit Mode Transition Logic
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Solution Overview
Problem
Conventional hybrid vehicles face challenges in smoothly transitioning from hybrid drive mode to electric drive mode, affecting fuel efficiency and driver comfort due to the order of engine defueling and clutch disengagement.
Innovation Solution
A hybrid vehicle control system that selects an appropriate mode transition pattern based on the change in driving force, either disengaging the clutch prior to engine defueling or stopping the engine prior to clutch disengagement, to minimize shocks and unnecessary fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is defueled before the first clutch is disengaged, then fuel efficiency is improved, but driving smoothness deteriorates due to sudden shock
Solution Approach 1:
The clutch disengagement is performed as a preliminary action before engine defueling. By disengaging the clutch first to separate the engine from the motor/generator, the system prepares the powertrain for mode transition, then subsequently defuels the engine without causing shock to the drivetrain. This sequence of preliminary clutch disengagement followed by engine stop resolves the contradiction by prioritizing driving smoothness while still achieving fuel efficiency.
2Ease of operation
If the first clutch is disengaged before engine defueling, then driving smoothness is improved, but fuel consumption increases due to unnecessary engine operation
Solution Approach 1:
The clutch disengagement is executed as a preliminary step before engine defueling. This preliminary separation of the engine from the drivetrain allows the engine to be stopped subsequently without causing shock, while the timing is optimized to minimize unnecessary fuel consumption during the transition period.
Solution Approach 2:
The control system dynamically adjusts the mode transition pattern based on real-time driving conditions, including accelerator opening degree and vehicle speed. By making the transition dynamic and adaptive rather than fixed, the system optimizes the balance between driving smoothness and fuel consumption for each specific operating scenario.
3Device complexity
If the mode transition pattern is fixed, then control simplicity is maintained, but adaptability to different driving conditions deteriorates
Solution Approach 1:
The control system transitions from a fixed mode transition pattern to a dynamic one that adapts to different driving conditions. The control unit determines the appropriate transition pattern (whether to disengage clutch before or after engine defueling) based on real-time parameters such as accelerator opening degree and vehicle speed, enabling the system to optimize performance for each specific scenario.
Solution Approach 2:
The system changes the control parameters (timing of clutch disengagement relative to engine defueling) based on varying operating conditions. By adjusting these parameters dynamically according to accelerator opening degree, vehicle speed, and other driving conditions, the system achieves adaptability while maintaining reasonable control complexity through structured decision logic.
Data Source
AI summary
A hybrid vehicle control system for cutting off fuel to an internal combustion engine of hybrid vehicle while providing smooth transitions from a hybrid drive mode to an electric drive mode is provided. The hybrid vehicle control system includes an integrated controller configured to receive inputs corresponding to vehicle speed and an indicated driving force, and to select an appropriate mode transition pattern from a group of mode transition patters according to the change in indicated driving force.