Vehicle Control Unit Torque Increment Adaptation
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Solution Overview
Problem
When engine brake torque control is executed simultaneously with anti-lock braking control, the engine brake can work excessively, leading to a higher tendency for wheels to lock, causing instability in vehicle behavior.
Innovation Solution
A vehicle control unit with a torque increment setting module that adjusts the drive source brake torque based on slip amounts when anti-lock braking control is not executed, and uses alternative parameters like road surface friction coefficient and body speed when both controls are executed, to prevent excessive brake torque and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine brake torque control is executed based on slip amount while anti-lock braking control is in execution, then the engine brake torque control can be executed, but the engine brake works excessively when wheel locking tendency recovers, causing wheels to lock easily and vehicle instability
Solution Approach 1:
The patent applies dynamics by making the torque increment setting adaptive based on operating conditions. The control system dynamically switches between two torque increment settings: a first torque increment when anti-lock braking is not executed, and a second (smaller) torque increment when anti-lock braking is in execution. This dynamic adjustment prevents excessive engine brake torque that would cause wheel locking and vehicle instability, while maintaining effective torque control for preventing wheel slip.
Solution Approach 2:
The patent changes the parameter of torque increment based on the execution state of anti-lock braking control. When anti-lock braking is active, the system switches to a smaller torque increment value to prevent excessive brake torque application. This parameter change resolves the contradiction by allowing engine brake torque control to function effectively without causing the harmful effect of excessive braking and wheel locking.
2Reliability
If drive source brake torque is increased to prevent wheel slip, then wheel slip prevention is improved, but noise from increased drive source output increases
Solution Approach 1:
The patent changes the torque increment parameter based on the operational context. By using a smaller second torque increment when anti-lock braking is in execution, the system prevents excessive drive source output that would generate noise, while still maintaining sufficient torque control to prevent wheel slip. This parameter adaptation resolves the contradiction between effective slip prevention and noise reduction.
3Force
If torque increment is set to larger value to ensure braking force, then braking force is improved, but excessive brake torque causes wheel locking tendency and instability
Solution Approach 1:
The patent applies dynamics by implementing conditional torque increment settings that adapt to the braking situation. The system uses a first torque increment setting for normal conditions and switches to a second, smaller torque increment when anti-lock braking control is active. This dynamic adjustment ensures sufficient braking force is available when needed while preventing excessive brake torque that would cause wheel locking and vehicle instability.
Data Source
AI summary
The embodiment provides a vehicle control unit including a torque increment setting module related to a drive source brake torque control and an anti-lock braking control module related to an anti-lock braking control. The torque increment setting modules includes a first setting module and a second setting module. The first setting module sets the torque increment based on at least a slip amount of a wheel when the drive source brake torque control is in execution but the anti-lock braking control is not executed. The second setting module sets the torque increment based on a parameter other than the slip amount when both the drive source brake torque control and the anti-lock braking control are in execution.