Hybrid Vehicle Engine Clutch Lock-Up Control via Virtual Speed Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional engine clutch lock-up control methods in hybrid vehicles face challenges due to variations in engine speed profiles caused by factors like combustion timing, engine temperatures, and intake air temperatures, leading to engine speed overrun or decrease phenomena, which hinder smooth synchronization between engine and motor speeds, resulting in delayed or incomplete torque synchronization.
Innovation Solution
A system and method that adaptively adjust the torque reduction ratio of the hybrid starter generator (HSG) by determining a virtual engine speed and calculating a correction reduction ratio based on the difference between actual and target engine speeds, using a 2-D map to synchronize engine and motor speeds during the engine firing process, ensuring smooth lock-up of the engine clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional engine clutch lock-up control methods are used, then the system structure is simple, but engine speed synchronization performance deteriorates due to overrun or decrease phenomena
Solution Approach 1:
The controller continuously monitors actual engine speed and compares it with target engine speed, using the speed difference as feedback to dynamically adjust HSG torque reduction ratio. This closed-loop feedback mechanism enables precise synchronization compensation without requiring complex mechanical structures.
Solution Approach 2:
The system dynamically changes the torque reduction ratio parameter of the HSG based on real-time engine speed conditions. By adjusting this parameter adaptively, the controller compensates for engine speed variations and achieves precise synchronization, resolving the contradiction between synchronization precision and system complexity.
2Manufacturing precision
If the torque reduction ratio of HSG is adjusted to synchronize engine and motor speeds, then synchronization performance is improved, but excessive adjustment causes performance degradation
Solution Approach 1:
The system dynamically adjusts the torque reduction ratio based on real-time engine speed conditions rather than using fixed ratios. This dynamic adaptation allows the system to optimize synchronization performance while avoiding excessive adjustments that could compromise reliability.
Solution Approach 2:
The controller automatically monitors engine speed and self-adjusts the HSG torque reduction ratio without external intervention. This self-service mechanism ensures that adjustments remain within optimal ranges, preventing performance degradation while maintaining synchronization precision.
3Ease of operation
If the HSG torque is reduced with a constant slope, then the control method is simple, but engine speed synchronization is delayed or incomplete
Solution Approach 1:
The system transitions from constant slope torque reduction to dynamic torque reduction ratio adjustment. The controller continuously adapts the torque reduction ratio based on the difference between actual and target engine speeds, achieving complete and accurate synchronization while maintaining operational simplicity through automated control.
Solution Approach 2:
The torque reduction ratio is changed as a dynamic parameter rather than a fixed value. This parameter change approach allows the system to achieve precise synchronization by adapting the torque reduction characteristics to real-time engine conditions, improving synchronization completeness without complicating the control method.
4Adaptability or versatility
If the engine speed profile varies due to combustion timing and temperature conditions, then the system adapts to different operating conditions, but synchronization accuracy deteriorates
Solution Approach 1:
The controller uses feedback from actual engine speed measurements to compensate for variations caused by different operating conditions. By continuously comparing actual speed with target speed and adjusting HSG torque accordingly, the system maintains high synchronization accuracy across diverse operating conditions including varying combustion timing and temperatures.
Solution Approach 2:
The system changes the torque reduction ratio parameter adaptively in response to different operating conditions. This parameter adaptation enables the system to maintain precise synchronization accuracy whether the engine is operating under cold start conditions, hot operating conditions, or varying combustion timing scenarios.
Data Source
AI summary
A system for controlling a lock-up of engine clutch may include an engine and a motor; the engine clutch mounted between the engine and the motor and configured to selectively transmit power of the engine between the engine and the motor; a hybrid starter generator (HSG) connected to a crank pulley of the engine and driven to start the engine; and a controller connected to the HSG and configured to determine a virtual engine speed in an engine firing process and a torque reduction ratio of the HSG according to the virtual engine speed after an engine cranking process and determine a correction reduction ratio with respect to the torque reduction ratio of the HSG using a difference value between the virtual engine speed and an actual engine speed, and adjust an increase or a decrease of the torque reduction ratio of the HSG to synchronize an engine speed with a motor speed for the lock-up of the engine clutch.