Negative Wheel Slip Control via Wheel Speed Derivative
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Solution Overview
Problem
Traditional engine control systems fail to accurately control engine torque output and do not provide rapid responses to control signals, nor coordinate torque control among various devices affecting engine torque output effectively.
Innovation Solution
An engine control system comprising a derivative module and a slip remediation module that determines the mathematical derivative of driven wheel speed, disabling regenerative braking, increasing axle torque, and unlocking the torque converter when the derivative is more negative than a predetermined deceleration, while also considering vehicle speed, traction control system status, and system faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional engine control systems are used to control engine torque output, then the system structure is simple, but the torque output control accuracy is insufficient and response speed is slow
Solution Approach 1:
The control system is segmented into multiple functional modules: derivative module (calculates wheel speed derivative), slip detection module (detects negative wheel slip events), remediation module (executes corrective actions), and disabling module (manages system state transitions). This modular segmentation enables precise torque control through coordinated operation of specialized subsystems while maintaining manageable overall complexity.
Solution Approach 2:
The system implements feedback control by continuously monitoring driven wheel speed, calculating its derivative, detecting slip events, and executing remediation actions based on real-time conditions. The feedback loop includes state monitoring (wheel speed derivative thresholds) and corrective feedback (torque adjustments via remediation module), enabling accurate and responsive torque output control.
2Use of energy by moving object
If regenerative braking is performed by electric motors, then energy recovery is achieved, but negative wheel slip events occur causing loss of traction and stability
Solution Approach 1:
The system uses feedback control to monitor wheel speed derivative during regenerative braking. When negative wheel slip is detected (derivative exceeds threshold), the remediation module provides corrective feedback by adjusting torque distribution or disabling regenerative braking temporarily, thus maintaining stability while preserving energy recovery during normal operation.
Solution Approach 2:
The system applies preliminary anti-action by detecting the onset of negative wheel slip through derivative calculation and executing remediation actions before significant traction loss occurs. The slip detection and remediation mechanism preemptively counteracts the destabilizing effect of regenerative braking, maintaining vehicle stability while allowing energy recovery to continue.
3Measurement precision
If the mathematical derivative of wheel speed is used to detect negative wheel slip, then detection accuracy is improved, but computational complexity increases
Solution Approach 1:
The system replaces complex mechanical slip detection mechanisms with computational derivation. Instead of using mechanical sensors or complex signal processing hardware, the derivative module computationally calculates wheel speed derivative from standard wheel speed sensor data, achieving high detection accuracy with minimal additional hardware complexity.
Data Source
AI summary
An engine control system comprises a derivative module and a slip remediation module. The derivative module determines a mathematical derivative of a driven wheel speed of a vehicle. The slip remediation module, when the mathematical derivative is more negative than a predetermined deceleration, at least one of disables regenerative braking being performed by one or more electric motors, increases an axle torque request, and unlocks a torque converter.