Brake System Pump Control for Noise Reduction
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Solution Overview
Problem
High-speed pumps in brake systems of motor vehicles generate unacceptable noise levels, necessitating a compromise between braking dynamics and noise development, which is challenging to achieve and may underestimate required speeds.
Innovation Solution
The method adapts pump output based on current brake fluid delivery requirements, determined by pressure changes, and accounts for dead volume in the brake circuits to maintain low noise levels while ensuring sufficient braking performance, by increasing pump power linearly with pressure changes and filling dead volume before increasing pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed pumps are used to achieve sufficient brake fluid delivery for emergency braking, then braking dynamics are improved, but noise level increases to an unacceptable level
Solution Approach 1:
The pump control system dynamically adjusts pump speed based on real-time braking requirements. The control device receives braking signals and calculates required pump output by considering pressure gradient, accumulator filling level, and dead volume, enabling the pump to operate at high speed only when necessary for emergency braking while running at low speed during normal conditions to minimize noise.
Solution Approach 2:
The system changes operational parameters (pump speed, delivery rate) based on braking intensity requirements. By calculating the required pump output using the formula q = V0/T + E·dp/dt, the system optimizes pump parameters to provide high delivery rates for emergency braking while maintaining low noise levels during conventional braking through reduced pump speed.
2Loss of time
If pump speed is increased to meet emergency braking requirements, then braking response time is improved, but the compromise between braking dynamics and noise becomes difficult to achieve
Solution Approach 1:
The control device pre-calculates the required pump output by considering the dead volume V0 that must be filled before pressure build-up begins. This preliminary calculation ensures that the pump is already delivering fluid to fill dead volumes when braking is initiated, reducing response time without requiring excessively high pump speeds throughout the entire braking process.
Solution Approach 2:
The system uses feedback from pressure sensors and accumulator level monitoring to continuously adjust pump speed. The control device receives actual pressure gradient measurements and accumulator filling level information to optimize pump output in real-time, ensuring sufficient braking response while minimizing noise by avoiding unnecessary high-speed operation.
3Object-generated harmful factors
If a fixed pump speed compromise is specified based on empirical values, then noise is reduced, but the required speeds may be underestimated for emergency braking
Solution Approach 1:
The system replaces fixed empirical speed specification with a feedback-based control system that continuously monitors pressure gradient, accumulator filling level, and braking signals. This enables the pump speed to be dynamically adjusted to meet actual braking requirements, ensuring sufficient performance for emergency braking while minimizing noise during normal operation.
Solution Approach 2:
The patent transitions from static pump speed specification to dynamic pump control. The control device calculates optimal pump speed in real-time based on current system state (dead volume status, pressure gradient, accumulator level), allowing the system to reliably meet emergency braking demands without the noise penalties of continuously high-speed operation.
4Speed
If pump power is increased linearly with pressure change requirements, then braking dynamics are maintained, but energy consumption increases
Solution Approach 1:
The system optimizes pump power parameters based on actual pressure build-up requirements. By using the formula q = V0/T + E·dp/dt, the control device calculates the minimum necessary pump delivery rate to achieve the required pressure gradient dp/dt, avoiding excessive energy consumption while maintaining sufficient braking dynamics through precise parameter matching.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces noise in the vehicle while maintaining high braking performance, ensuring the braking system meets dynamic demands without excessive noise, and accurately responds to braking requests.
Implementation Method 1
Pumps are used in braking systems for motor vehicles in order to enable active braking. The pumps are designed in such a way that they can pump sufficient brake fluid into the brake lines for each required braking effect within a specified period of time.
Implementation Method 2
The wheel brakes (15, 16) on one of the main brake lines (14) can be operated as shown in 1 braking a front wheel and a diagonally opposite rear wheel.
Data Source
Figure 1
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Figure 4~5
AI summary
A method for controlling a brake system comprises the following steps: receiving a brake signal for setting a brake action by the brake system; determining a minimum rate of a pressure increase in the brake system in order to effect the brake action within a predetermined response time, and setting a pump power of a pump of the brake system such that the pressure in the brake system increases in accordance with the minimum rate.