Hybrid Vehicle Controller Torque Management for HSG Failure
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Solution Overview
Problem
Hybrid vehicles without reverse gear face difficulties in reverse driving and battery overcharging when the hybrid starter & generator (HSG) malfunctions, as conventional fail-safe strategies involve shutting off the main relay, making reverse drive impossible and risking battery overcharge due to back electromotive force.
Innovation Solution
An apparatus and method for controlling a hybrid vehicle that maintains the main relay on and adjusts vehicle torque control based on the battery's state of charge (SoC) to enable reverse drive and prevent overcharging, by unlocking the engine clutch for reverse drive requests and locking it up for forward drive, and modifying torque splitting between engine and motor torque to manage battery charging states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main relay is turned off to prevent battery overcharging when HSG fails, then battery safety is improved, but reverse drive capability is lost
Solution Approach 1:
The patent changes the control parameter from binary (main relay on/off) to continuous (torque distribution based on SoC). By adjusting the torque demand distribution between engine and motor according to battery state of charge, the system prevents overcharging while maintaining main relay on, enabling reverse drive capability to be preserved.
Solution Approach 2:
The patent introduces dynamic torque distribution control that adapts to real-time battery state of charge. Instead of a static main relay off command, the system dynamically adjusts engine and motor torque demands based on SoC levels, allowing the main relay to remain on while preventing battery overcharge through intelligent power management.
2Object-affected harmful factors
If the main relay is turned off when HSG fails, then battery overcharging is prevented, but operational flexibility is reduced
Solution Approach 1:
The patent implements a feedback control mechanism where the battery state of charge is continuously monitored and used to adjust torque demand distribution. This closed-loop control prevents battery overcharging by reducing motor torque demand when SoC is high, while maintaining main relay on and preserving full operational flexibility including reverse drive.
Solution Approach 2:
The system changes from a fixed fail-safe strategy (main relay off) to a dynamic parameter adjustment strategy (torque distribution based on SoC). This allows the main relay to remain on while preventing battery overcharge through real-time modification of engine and motor torque demands according to battery state of charge.
3Device complexity
If conventional fail-safe strategy is applied when HSG fails, then system simplicity is maintained, but reverse drive becomes difficult
Solution Approach 1:
The patent makes the torque control system multi-functional by enabling it to handle both normal operation and fail-safe conditions through a unified control architecture. The same torque demand distribution mechanism works in both normal and HSG failure modes, eliminating the need for separate control strategies and preserving reverse drive capability while maintaining system simplicity.
Solution Approach 2:
The patent introduces dynamic adaptation to failure conditions without increasing overall system complexity. The torque control system automatically adjusts its behavior based on HSG status, transitioning seamlessly from normal to fail-safe mode while maintaining reverse drive capability. This dynamic response eliminates the need for complex separate fail-safe control logic.
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
Enables reverse drive functionality and prevents battery overcharging by continuously maintaining the main relay on and adjusting torque control calculations based on SoC, ensuring fail-safe drive performance even when the HSG fails, thereby improving operational reliability and safety.
Implementation Method 1
since the battery may be overcharged due to back electromotive force generated from the HSG
Data Source
AI summary
An apparatus for controlling a hybrid vehicle and a method thereof are provided. The apparatus includes a hybrid starter & generator (HSG) controller that determines whether an HSG has failed, and a hybrid vehicle controller that controls reverse drive by controlling locking up an engine clutch and maintaining a main relay of a battery to be continuously turned on, based on whether a request for the reverse drive is input from a user. The hybrid vehicle controller changes and applies a vehicle torque control calculation method based on a state of charge (SoC) of the battery, when the HSG has failed.