Vehicle Axle Wheel Hop Control via Brake Pressure Pulsing
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Solution Overview
Problem
During certain vehicle maneuvers, the rear solid beam axle can resonate, causing wheel hop, which is damaging to rear axle components, especially when the axle differential is locked and the vehicle is turning, due to high torques and frequencies.
Innovation Solution
A method involving pulsing brake pressure and reducing engine torque is implemented when specific conditions are met, such as differences in wheel speeds and lock ring torque frequencies exceeding reference values, using ABS sensors and engine control parameters to mitigate wheel hop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the axle differential is locked to improve traction, then wheel hop resonance is exacerbated causing damage to rear axle components
Solution Approach 1:
The control system applies preliminary anti-action by detecting wheel hop conditions through sensors (accelerometers, speed sensors) and preemptively adjusting engine torque and brake pressure before damage occurs. The system monitors frequency and amplitude of axle vibrations and counteracts the harmful resonance by reducing engine torque and applying pulsing brake pressure to the rear wheels, thereby preventing damage to the locked differential and axle components while maintaining traction.
Solution Approach 2:
The system changes operating parameters dynamically by adjusting engine torque output and brake pressure based on detected wheel hop conditions. When wheel hop is detected (frequency exceeding threshold and amplitude above threshold), the control module reduces engine torque and applies pulsing brake pressure, thereby changing the mechanical parameters acting on the axle to eliminate the resonant condition and prevent component damage.
2Power
If high engine torque is applied to improve vehicle performance, then wheel hop resonance is triggered causing damage to axle components
Solution Approach 1:
The system implements feedback control by continuously monitoring axle vibrations using accelerometers and speed sensors, comparing the detected frequency and amplitude against threshold values, and automatically adjusting engine torque and brake pressure in response. When wheel hop conditions are detected (resonant frequency and excessive amplitude), the control module reduces engine torque and applies pulsing brake pressure, creating a closed-loop feedback system that prevents component damage while allowing high power delivery under normal conditions.
Solution Approach 2:
The system transitions from static torque application to dynamic torque management by continuously adjusting engine torque output based on real-time detection of wheel hop conditions. The control module modulates engine torque and brake pressure dynamically, allowing high torque delivery when safe and reducing torque when resonance is detected, thereby adapting the power delivery characteristics to prevent axle component damage.
Data Source
AI summary
A method for controlling wheel hop at a vehicle axle includes determining that one of a difference between average front and rear wheel speeds exceeds a reference difference, a frequency of a signal produced by an accelerometer mounted on the axle exceeds a reference frequency, and a frequency of a lock ring torque exceeds a second reference frequency; pulsing pressure in the wheel brakes of the axle; and reducing engine torque.