Hybrid Vehicle Torque Control Gradient Restoration
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Solution Overview
Problem
Hybrid vehicles with multiple power sources face issues in maintaining torque continuity and preventing abrupt impacts when torque reduction control is released, leading to deteriorated drivability due to step-like torque differences and varying dynamic characteristics between engine and motor.
Innovation Solution
A system and method for controlling torque in hybrid vehicles that involves an engine clutch, a driving information detector, and a traction controller, which sets a constant gradient for torque restoration of the engine and motor when torque reduction control is released, ensuring smooth output torque transitions and following demand torque without steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If torque reduction control is released and output torque of power sources is restored to demand torque, then driving demand torque is satisfied, but step-like difference in torque commands and response performance occurs between engine and motor causing abrupt torque change
Solution Approach 1:
The patent applies dynamics by making the torque restoration process adaptive rather than static. When TCS control is released, the system dynamically adjusts the restoration gradient based on the operating state (engine-only, motor-only, or combined operation) to ensure smooth torque transitions. This dynamic adjustment prevents abrupt torque changes while satisfying driving demand, resolving the contradiction between productivity and stability.
Solution Approach 2:
The patent changes the parameter of torque restoration gradient based on different operating conditions. By setting different restoration gradients for engine and motor depending on whether the vehicle is in engine-only mode, motor-only mode, or combined mode, the system achieves smooth torque transitions. This parameter adaptation resolves the contradiction by allowing flexible torque management that maintains both driving performance and torque continuity.
2Speed
If output torque of power sources is abruptly changed when TCS control is released, then response to driving demand is improved, but actual output torques differ according to dynamic characteristics causing deteriorated drivability
Solution Approach 1:
The patent applies preliminary action by pre-setting appropriate restoration gradients for the engine and motor before torque restoration begins. Based on the current operating state, the system determines in advance how each power source should restore its torque, ensuring coordinated restoration that maintains drivability. This preliminary planning prevents abrupt torque changes while maintaining responsive driving performance.
3Reliability
If torque reduction control is applied to prevent wheel slip, then wheel slip prevention is achieved, but torque continuity is interrupted when control is released
Solution Approach 1:
The patent applies feedback by continuously monitoring the operating state (which power sources are active) and adjusting the torque restoration strategy accordingly. When TCS control is released, the system uses feedback from the current operating condition to determine appropriate restoration gradients for each power source, ensuring smooth torque transitions that maintain continuity while preserving the wheel slip prevention capability.
Data Source
AI summary
A system for controlling torque for a hybrid vehicle includes a power source having an engine and a motor. An engine clutch is provided between the engine and the motor. A driving information detector detects demand torque for driving. A traction controller controls oil pressure supplied into a brake to prevent a wheel slip and request torque reduction control from a vehicle controller when the wheel slip is detected. A vehicle controller controls engagement of the engine clutch for driving in a hybrid electric vehicle (HEV) mode, wherein the vehicle controller determines output torques of the engine and the motor to perform torque reduction control according to the torque reduction control, and when the request for the torque reduction control is released, the vehicle controller sets a gradient for torque restoration of the engine and the motor and applies the gradient to follow the demand torque for driving.