Brake NVH Countermeasure via Pressure Range Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vehicle brake systems experience noise, vibration, and harshness (NVH) issues during braking, particularly at low caliper pressures, leading to costly warranty and part replacement issues, and rear axle brake-induced moan/groan problems.
Innovation Solution
A brake system with a brake pedal position sensor and electronic controller that adjusts braking pressure to maintain it outside a defined range causing NVH conditions, ensuring consistent deceleration and pedal feel by blending front and rear axle pressures, and using a look-up table to determine optimal pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If braking pressure is applied to stop the vehicle, then deceleration is achieved, but NVH noise and vibration occur at low caliper pressures
Solution Approach 1:
The system dynamically adjusts the braking pressure parameter to avoid the problematic low-pressure range that generates NVH noise. By changing the pressure parameter from the initially requested value to an adjusted value outside the NVH range, the system eliminates noise while preserving deceleration performance.
Solution Approach 2:
The electronic controller acts as an intermediary between the driver's brake pedal input and the actual brake actuation. It receives the initial pressure request, processes it through NVH range checks, and outputs an adjusted pressure command that avoids problematic ranges while achieving the desired deceleration.
2Object-affected harmful factors
If braking pressure is adjusted to avoid NVH ranges, then noise is reduced, but brake pedal feel may be affected
Solution Approach 1:
The system adjusts the pressure parameter while maintaining the relationship between pedal position and effective deceleration. By carefully selecting adjusted pressures that achieve the same deceleration target, the system preserves the expected pedal feel and performance characteristics.
3Object-affected harmful factors
If braking pressure is increased to eliminate instability, then NVH noise is reduced, but energy consumption increases
Solution Approach 1:
The system optimizes the pressure parameter by selecting the lowest effective pressure that achieves stable braking without NVH noise. Rather than consistently using high pressure, it dynamically selects the minimum necessary pressure outside the problematic range, minimizing energy consumption while eliminating instability.
Data Source
AI summary
Systems and methods are described for controlling a vehicle braking system. An electronic controller determines a target deceleration based at least in part on a detected displacement position of a brake pedal and determines an adjusted braking pressure to be applied to at least one wheel of the vehicle such that, regardless of the displacement position of the brake pedal and the target deceleration, the adjusted braking pressure is maintained outside of a defined range of braking pressures that corresponds to a NVH condition for the at least one wheel. The adjusted braking pressure is then applied to the at least one wheel of the vehicle.