Hybrid Vehicle Clutch Torque Lead Control for Smooth Mode Transitions
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Solution Overview
Problem
Hybrid vehicles face challenges in managing smooth transitions between electric and combustion driving modes, leading to sudden unwanted acceleration or deceleration due to difficulties in accurately estimating and applying torque to the clutch.
Innovation Solution
A method that estimates pressures at different locations of the clutch, computes torque lead values based on these pressures and time delays, and combines them to apply torque from the motor, ensuring smooth transitions by compensating for clutch coupling and drivetrain dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If torque is applied directly during mode transition, then the combustion engine can be engaged quickly, but sudden unwanted acceleration or deceleration occurs
Solution Approach 1:
The system calculates a torque lead value that represents the difference between commanded torque and estimated actual torque before the transition occurs. This preliminary torque calculation compensates for the inherent delay in clutch torque application, ensuring that the combustion engine is engaged smoothly without causing sudden acceleration or deceleration.
Solution Approach 2:
The system continuously estimates the actual clutch torque based on measured clutch input shaft speed and a look-up table containing clutch characteristics. This feedback mechanism allows the control system to adjust the motor torque in real-time to maintain smooth transitions and prevent unwanted vehicle acceleration or deceleration.
2Loss of time
If clutch torque is increased to engage combustion engine faster, then transition time is reduced, but vehicle speed stability deteriorates
Solution Approach 1:
The system dynamically adjusts the motor torque during the transition by calculating the torque lead value based on real-time conditions. The torque lead is computed as the difference between the commanded torque and the estimated actual clutch torque, allowing the system to optimize both transition speed and vehicle speed stability adaptively.
Solution Approach 2:
The system changes the motor torque parameter dynamically during the transition process. By adjusting the motor torque based on the calculated torque lead and estimated actual clutch torque, the system achieves rapid engagement while maintaining vehicle speed stability.
3Ease of operation
If motor torque is reduced during clutch engagement, then vehicle acceleration is minimized, but combustion engine engagement is delayed
Solution Approach 1:
The system uses the electric motor to substitute for the clutch during the transition period. The motor provides the necessary torque to maintain vehicle speed while the clutch engages the combustion engine, eliminating the need to reduce motor torque and avoiding delays in combustion engine engagement.
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
The method ensures smooth transitions between operational modes, minimizing unwanted acceleration or deceleration, and maintaining vehicle speed by accurately estimating and applying torque, thus improving energy efficiency and safety.
Implementation Method 1
applying torque from a motor of the vehicle based on the third torque lead value
Implementation Method 2
the clutch coupling the combustion engine to the drivetrain
Data Source
AI summary
A method includes estimating a first pressure at a first location of a clutch based on a flow rate of a fluid in the clutch, computing a first torque lead value based on the first pressure, computing a second torque lead value based on a second pressure, computing a third torque lead value by combining the first torque lead value and the second torque lead value, and applying torque from a motor of the vehicle based on the third torque lead value.