Adaptive Traction Control Threshold for Catalyst Protection
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Solution Overview
Problem
Conventional traction control systems execute power reduction irrespective of the drive wheel's gripping state, leading to undesirable traction control and catalyst deterioration due to imperfect combustion and uneven fuel gas concentration in the engine's catalyst.
Innovation Solution
A traction control system that includes a detector to monitor the drive wheel's spin value, a condition determiner to set variable driving power suppressing conditions based on rotation number differences and drive system rotation change rates, and a controller to execute traction control, thereby predicting the gripping state and avoiding unnecessary power reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ignition timing of the engine is retarded to reduce driving power, then the traction control is executed to restore gripping force of the drive wheel, but imperfect combustion occurs and fuel gas remains in the cylinder which flows to the catalyst and causes local excessive temperature rise leading to catalyst deterioration
Solution Approach 1:
The patent changes the threshold parameter for traction control activation from a fixed spin value to a variable threshold based on the change rate of spin value. When the change rate is high (indicating rapidly deteriorating grip), the threshold is lowered to activate control sooner. When the change rate is low (indicating stable or improving grip), the threshold is raised to prevent unnecessary activation. This parameter adaptation prevents catalyst deterioration by avoiding unnecessary ignition timing retardation while maintaining reliability when actually needed.
2Reliability
If the traction control is executed to reduce driving power when the monitored value exceeds the predetermined value, then the gripping force of the drive wheel is restored, but the traction control is executed undesirably even when the driving power is favorably maintained or increased
Solution Approach 1:
The patent introduces dynamics to the traction control system by making the threshold value adaptive rather than fixed. The threshold dynamically adjusts based on the change rate of the spin value, allowing the system to respond appropriately to different road conditions. This dynamic adjustment prevents undesired activation during favorable gripping conditions while ensuring timely activation when grip is deteriorating rapidly.
Solution Approach 2:
The system uses feedback from the spin value change rate to adjust the threshold for traction control activation. By continuously monitoring how quickly the spin value is changing and using this information to adjust the threshold, the system creates a feedback loop that prevents unnecessary activation while maintaining responsiveness to actual grip deterioration.
Data Source
AI summary
A traction control system comprises a detector configured to detect a monitored spin value corresponding to a spin amount of a drive wheel in a vehicle; a condition determiner configured to determine whether or not the monitored spin value detected by the detector meets a driving power suppressing condition; and a controller configured to execute a traction control for reducing a driving power of the drive wheel based on the determination; the condition determiner being configured to set the driving power suppressing condition variably based on at least one of a variable parameter relating to a rotation number difference which is variable according to a change rate of a rotation number difference between the drive wheel and a driven wheel, and a variable parameter relating to rotation of a drive system which is variable according to a rotation change rate of the drive system for driving the drive wheel.