Hybrid Vehicle Torque Control for Brake Override Response
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Solution Overview
Problem
Existing hybrid vehicle control systems, such as brake override systems, face challenges in ensuring sufficient re-acceleration after a curve, as they reduce engine torque when both accelerator and brake pedals are pressed, leading to delayed recovery of drive force and deteriorated drivability.
Innovation Solution
A hybrid vehicle control device that reduces output to the drive wheels by controlling motor torque and maintaining engine torque during simultaneous accelerator and brake operations, allowing for quicker recovery of drive force by increasing motor torque responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake override system reduces engine torque when accelerator and brake operations are simultaneous, then braking priority is achieved, but re-acceleration performance deteriorates
Solution Approach 1:
The patent segments the torque reduction function between engine torque and motor torque. Instead of reducing only engine torque (conventional approach), the system reduces motor torque while maintaining engine torque during brake override. This segmentation allows the braking priority function to be achieved through motor torque control, while engine torque remains ready for immediate re-acceleration, thus resolving the contradiction between braking reliability and re-acceleration performance.
Solution Approach 2:
The patent changes the parameter being controlled during brake override from engine torque to motor torque. By switching which torque component is reduced (from engine to motor), the system maintains the ability to quickly recover drive force since the engine torque can be immediately increased again, improving re-acceleration response while still achieving braking priority through motor torque suppression.
2Power
If engine torque is reduced during simultaneous accelerator and brake operations, then output control is achieved, but drive force recovery time increases
Solution Approach 1:
The patent divides the torque management into separate controllable components: engine torque and motor torque. During brake override, only motor torque is reduced while engine torque is maintained at its target value. This segmentation enables independent control of each torque source, allowing the engine to remain in a state ready for immediate power delivery, thereby reducing drive force recovery time while maintaining output control through motor torque management.
Solution Approach 2:
The patent prepares the engine torque in advance by maintaining it at the target value during brake override operations. This preliminary action ensures that when the brake override is lifted, the engine torque is already positioned to provide immediate drive force recovery, eliminating the delay that would occur if engine torque had been reduced. This advance preparation directly addresses the time loss issue while maintaining necessary output control.
Data Source
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AI summary
A hybrid vehicle includes, as a drive source, a hybrid system that has an engine and a motor. When the accelerator and the brake pedal are simultaneously depressed (S100: Yes), the output transmitted to the drive wheels is decreased by controlling the motor torque, while maintaining the engine torque. Therefore, when the decrease in output is cancelled, the recovery in the drive force of the hybrid vehicle is achieved by an increase in the motor torque, which is more responsive than the engine torque.