Brake Pump Speed Adjustment for NVH Reduction
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Solution Overview
Problem
Existing brake pump systems face challenges in adjusting maximum pump speed to achieve optimal deceleration rates, leading to potential jerking, noise, vibration, and harshness (NVH) issues, as well as inefficiencies in deceleration times, due to fixed maximum operational speeds that do not adapt to changing deceleration requirements.
Innovation Solution
A vehicle system that includes a brake pump with an adjustable maximum pump speed, regulated by a maximum speed regulator, which determines the target deceleration and adjusts the pump speed based on the rate of change of deceleration and the difference between target and measured deceleration to optimize braking performance and reduce NVH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the brake pump operates at a fixed maximum speed, then the deceleration response is fast, but the system produces jerking, noise, vibration, and harshness (NVH) issues
Solution Approach 1:
The brake pump maximum speed is changed from a fixed parameter to a dynamically adjustable parameter. The controller continuously monitors the buffer distance between the host vehicle and target vehicle, and adjusts the brake pump speed accordingly - operating at higher speeds when larger buffers exist and at lower speeds when buffers are smaller, thereby eliminating jerking and NVH while maintaining fast response capability
Solution Approach 2:
The operational parameters of the brake pump are changed by adjusting its maximum speed based on real-time deceleration requirements. The system calculates the required deceleration rate based on buffer distance and adjusts the brake pump speed parameter to match the actual deceleration demand, preventing excessive speed that causes NVH while ensuring sufficient speed for rapid deceleration when needed
2Productivity
If the brake pump operates at a high maximum speed, then the deceleration rate is high, but the system consumes more energy and increases NVH
Solution Approach 1:
The brake pump speed parameter is dynamically adjusted based on the actual deceleration requirement calculated from buffer distance. The controller calculates the precise deceleration rate needed to maintain safe following distance and sets the brake pump speed to match this requirement, avoiding unnecessary high-speed operation that wastes energy while ensuring sufficient deceleration performance when required
3Object-affected harmful factors
If the brake pump maximum speed is adjusted dynamically, then the NVH is reduced, but the system complexity increases
Solution Approach 1:
The controller performs multiple functions using a single integrated system: it calculates buffer distance based on relative position and velocity data, determines the required deceleration rate, and adjusts the brake pump maximum speed accordingly. This multi-functional approach avoids the need for separate dedicated components for each function, thereby reducing overall system complexity while achieving NVH reduction through dynamic speed adjustment
Data Source
AI summary
Method and apparatus are disclosed for adjustment of maximum brake pump speed based on rate of change of target deceleration. An example vehicle includes a brake pump having a maximum pump speed. The example vehicle also includes a vehicle decelerator to determine a target deceleration for autonomous deceleration and send a signal to the brake pump to decelerate the vehicle at the target deceleration. The example vehicle also includes a maximum speed regulator to determine a rate of change of the target deceleration and adjust the maximum pump speed based on the rate of change.