Hybrid Vehicle Engine Control for Disabled Motor Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid electric vehicles with a disabled drive motor are limited to low speeds due to existing control strategies, which either disable drive mode or enter a 'creep' mode, negatively impacting customer satisfaction.
Innovation Solution
A control strategy that commands engine power to be the lesser of two calculated powers: one sufficient to satisfy driver wheel torque requests at current engine speed and another corresponding to maximum engine torque at a target engine speed set to achieve a desired battery state of charge, allowing for higher speeds without overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the drive motor is unavailable and the vehicle enters creep mode, then the battery state of charge is maintained, but the vehicle speed is severely limited
Solution Approach 1:
The control strategy changes the operating parameters of the engine by calculating a target engine speed based on battery state of charge and adjusting engine power accordingly. The engine operates at optimized speeds to maintain battery charge while enabling higher vehicle speeds than traditional creep mode, directly resolving the contradiction between speed limitation and battery control.
2Force
If the engine power is increased to satisfy driver torque request at current engine speed, then the wheel torque requirement is met, but the battery may become overcharged
Solution Approach 1:
The control strategy implements feedback control by continuously monitoring battery state of charge and adjusting engine power output accordingly. The target engine speed calculation incorporates battery state of charge feedback, allowing the system to dynamically balance wheel torque delivery with battery charge management, preventing overcharging while meeting torque demands.
Solution Approach 2:
The system dynamically adjusts engine operating parameters based on real-time conditions. By calculating target engine speed as a function of current battery state of charge and adjusting engine power dynamically rather than operating at fixed parameters, the system achieves both torque delivery and battery protection.
3Speed
If the engine operates at maximum torque to provide higher vehicle speeds, then the speed limitation is overcome, but the battery charging control is compromised
Solution Approach 1:
The control strategy optimizes engine operating parameters by calculating a target engine speed that balances power delivery with battery charge management. Rather than operating at maximum torque regardless of conditions, the system adjusts engine speed and power output parameters dynamically to achieve both higher vehicle speeds and maintain battery state of charge within desired ranges.
Data Source
AI summary
A method for controlling an engine in a hybrid electric vehicle according to the present disclosure includes, in response to a drive motor being unavailable, commanding an engine power equal to the lesser of a first and a second power. The first power is sufficient to satisfy a driver wheel torque request at the current engine speed, and the second power corresponds to a maximum engine torque available at a target engine speed, where the target engine speed is selected to attain a desired battery state of charge.