Hybrid Vehicle Launch Control via Unified Torque Regulation
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Solution Overview
Problem
In hybrid vehicles, achieving optimal performance during vehicle launch is challenging due to tradeoffs in controller calibration, which affect engine efficiency, driveline noise, and vibration, often requiring complex tuning of engine, torque converter, and electric machine controllers.
Innovation Solution
A driveline operating method that adjusts torque converter clutch torque capacity and electric machine torque using a cost function incorporating torque converter slip error and vehicle speed error, simplified through a linear quadratic regulator (LQR) to unify relationships between electric machine torque, torque converter slip, and engine torque, thereby simplifying vehicle calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual controllers are tuned to provide desired vehicle performance, then vehicle performance is improved, but controller calibration complexity increases
Solution Approach 1:
The patent combines the control of engine torque, electric machine torque, and torque converter clutch torque into a unified control system. Instead of independently tuning three separate controllers, the invention uses a single cost function that simultaneously optimizes all three control parameters, merging the calibration process into one coordinated effort rather than multiple independent tuning procedures
Solution Approach 2:
The cost function serves as a universal control mechanism that handles multiple control objectives simultaneously. It integrates engine efficiency optimization, driveline noise and vibration reduction, and torque converter slip management into a single multi-functional calibration approach, eliminating the need for separate tuning procedures for each control parameter
2Use of energy by moving object
If engine speed is increased to increase engine efficiency, then engine efficiency is improved, but torque converter slip increases reducing driveline efficiency
Solution Approach 1:
The invention dynamically adjusts the torque converter clutch torque capacity based on real-time operating conditions rather than using a fixed relationship. The clutch torque capacity is continuously optimized as a decision variable in the control system, allowing the system to adaptively balance engine speed requirements against driveline slip losses under varying vehicle conditions
Solution Approach 2:
The system changes the torque converter clutch torque capacity parameter dynamically based on the cost function optimization. By treating clutch torque capacity as a variable parameter rather than a fixed value, the system can adjust this parameter in real-time to maintain optimal balance between engine efficiency and driveline slip, resolving the tradeoff between these two competing objectives
Data Source
AI summary
Systems and methods for operating a driveline of a hybrid vehicle are described. In one example, vehicle launch is controlled according to a linear quadratic regulator that provides feedback control according to torque converter slip error and vehicle speed error. The vehicle launch is also controlled according to feed forward control that is based on requested torque converter slip and requested vehicle speed.