HEV Engine Clutch Engagement Timing Control
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Solution Overview
Problem
In conventional eco-friendly vehicles, switching from electric vehicle (EV) mode to hybrid electric vehicle (HEV) mode often results in inefficient engine operation due to mismatched engine and motor speed synchronization, leading to increased idling time or extended EV drive time, which affects fuel efficiency.
Innovation Solution
An engine operation control apparatus and method that determines the engine operation start time based on a lookup table, synchronizes engine RPM with motor RPM, and adjusts clutch engagement to minimize idling and operation time in EV mode by calculating and applying RPM correction values based on predefined conditions and learning outcomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine operation start time is determined based on a fixed rising slope of motor speed, then the engine clutch engagement can be matched to motor speed, but the idling time of the engine increases because vehicle states vary
Solution Approach 1:
The controller performs preliminary learning of the actual engine operation time and speed synchronization completion time during vehicle operation. This learned information is stored and used to determine the engine operation start time in subsequent EV-to-HEV mode switches, allowing the system to adapt to specific vehicle characteristics and minimize idling time while ensuring accurate clutch engagement timing.
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors the actual engine operation time and speed synchronization completion time, compares these with the determined engine operation start time, and uses this information to refine future timing decisions. This closed-loop control ensures that the engine starts at the optimal time to match clutch engagement availability while minimizing idle operation.
2Loss of time
If the engine operation start time is delayed to match clutch engagement availability, then engine idling time is reduced, but the EV drive time increases
Solution Approach 1:
The controller determines the engine operation start time in advance by retrieving learned values from memory, performing calculations based on the determined time, and setting the optimal start moment before the mode switch occurs. This preliminary determination ensures that the engine starts at the precise moment when clutch engagement becomes available, minimizing both idling time and unnecessary EV drive extension.
Solution Approach 2:
The system dynamically adjusts the engine operation start time based on real-time vehicle conditions and learned characteristics. The controller modifies the timing parameters according to the specific vehicle state, ensuring optimal performance that balances idling time reduction with maintaining appropriate EV drive duration.
3Device complexity
If the engine operation start time is determined without considering vehicle-specific variations, then the control system is simple, but the speed synchronization completion time cannot be precisely matched to clutch engagement availability
Solution Approach 1:
The control system performs self-learning by automatically monitoring and recording the actual engine operation time and speed synchronization completion time during vehicle operation. This self-acquired knowledge is stored in memory and used by the controller to determine optimal engine start timing, eliminating the need for complex external calibration systems while achieving precise timing accuracy specific to each vehicle.
Solution Approach 2:
The system implements feedback loops where the controller continuously monitors synchronization completion time and compares it with clutch engagement availability. This feedback information is used to refine the engine operation start time determination, ensuring precise timing matching while maintaining a relatively simple control architecture that adapts to vehicle-specific characteristics.
Data Source
AI summary
An engine operation control apparatus includes a controller configured to: decide an engine operation time point based on a lookup table in which a learning value that is previously learned is stored when a request to switch to an HEV mode occurs; determine whether to engage an engine clutch by comparing an engine RPM when a speed of an engine is synchronized with a speed of a motor with a first motor RPM; operate the engine at the engine operation time point and control engagement of the engine clutch depending on the determination; and store the engine operation time point based on a second motor RPM at a synchronization completion time point when a learning condition of the engine operation time point is satisfied when the speed of the engine and the motor are synchronized.