Adaptive Pump Control for Brake Pressure Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor vehicle brake systems face challenges in maintaining operational safety and user comfort during ABS-controlled braking, particularly due to inefficient pump control leading to fluctuations in pressure and pedal feel, especially in low-friction situations and varying operating conditions.
Innovation Solution
The brake system employs adaptive pump control based on real-time vehicle conditions, including low-pressure accumulator fill level and its derivative, wheel speeds, and temperature values, to optimize pump activation and reduce noise and energy consumption, utilizing a combined proportional-differential control system and PWM control to manage pump intervals dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is operated frequently to maintain low-pressure accumulator fill level, then operational safety is improved, but pump noise and energy consumption increase
Solution Approach 1:
The control unit continuously monitors the fill level of the low-pressure accumulator and uses this feedback information to determine when pump activation is necessary. This closed-loop control ensures the pump operates only when needed to maintain safety margins, avoiding unnecessary noise and energy consumption while ensuring operational safety is maintained through real-time level assessment
Solution Approach 2:
The system calculates the fill level in advance using a model that considers intake quantity during ABS control, pump delivery volume, and generator voltage. By determining the projected fill level before pump activation, the system can prevent unsafe conditions from developing while avoiding reactive pump operations that would increase noise and energy use
2Reliability
If the pump is operated frequently to maintain low-pressure accumulator fill level, then operational safety is improved, but energy consumption increases
Solution Approach 1:
The control unit continuously monitors the fill level of the low-pressure accumulator and uses this feedback information to determine when pump activation is necessary. This closed-loop control ensures the pump operates only when needed to maintain safety margins, avoiding unnecessary energy consumption while ensuring operational safety is maintained through real-time level assessment
Solution Approach 2:
The system calculates the fill level in advance using a model that considers intake quantity during ABS control, pump delivery volume, and generator voltage. By determining the projected fill level before pump activation, the system can prevent unsafe conditions from developing while avoiding reactive pump operations that would increase energy use
3Stability of the object's composition
If pump activation is increased to reduce low-pressure accumulator fill level, then pressure stability is improved, but pedal rebound increases
Solution Approach 1:
The control unit dynamically adjusts pump activation strategy based on real-time assessment of fill level, ABS control status, and driving conditions. Rather than using fixed pump activation thresholds, the system adapts its control parameters to balance pressure stability requirements with pedal feel considerations, reducing unnecessary pump cycles that cause pedal rebound while maintaining adequate pressure control
Solution Approach 2:
The system changes control parameters including pump activation thresholds and timing based on the assessed fill level and operating conditions. By adjusting these parameters dynamically, the system optimizes the balance between maintaining pressure stability and minimizing pedal rebound effects on the driver
4Speed
If pump delivery volume is increased to empty the low-pressure accumulator faster, then response time is improved, but pressure fluctuations increase
Solution Approach 1:
The control unit implements periodic pump activation with controlled duration and intervals, rather than continuous operation. By using multiple shorter pump cycles with appropriate spacing, the system achieves the necessary brake fluid return to the master cylinder while allowing pressure to stabilize between cycles, thus reducing harmful pressure fluctuations while maintaining adequate response time
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 ensures stable operational safety and comfort by minimizing pump activations, reducing pressure fluctuations, and maintaining sufficient free space in the low-pressure accumulator, effectively handling extreme situations and varying conditions.
Implementation Method 1
a pump (14) having a suction side and a pressure side, with the suction side connected to the low-pressure accumulator (13) and the pressure side connected to the master brake cylinder (2)
Implementation Method 2
low-pressure accumulator (13), designed to receive the volume of hydraulic fluid released from the wheel brake (8)
Data Source
Figure 1
AI summary
A motor vehicle brake system (1) having a hydraulic cable (4), via which a wheel brake module (6) can be pressurized by a brake medium using brake pressure from a brake cylinder (8) and to which a low pressure accumulator (13) is connected for temporarily receiving excess brake medium, wherein the low pressure accumulator (13) is connected to the hydraulic cable (4) via a backflow line (12) and a return pump (14) interposed in the return line (12) in order to return temporarily stored brake medium, the return pump (14) being cyclically actuated for adjusting the pump capacity such that an activation occurs within each braking cycle during a portion of pump cycles that corresponds to the pump capacity, is intended to provide particularly high operational safety while also providing a comfortable pedal sensation. For this purpose, a control unit (16) associated with the return pump (14) that is interposed in the backflow line (12) in an adaptive manner issues a control value for the number of pump cycles of the return pump (14) during a braking cycle, based on a predetermined initial value in consideration of the filling level in the low pressure accumulator (13), and/or the temporal derivative thereof.