Air Suspension Valve Block Pressure Sensing with Low-Pass Filtering
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Solution Overview
Problem
Existing air suspension systems for vehicles face challenges in precisely controlling the ventilation and venting of air springs due to inaccurate pressure measurements during dynamic pressure changes, particularly when pressure sensors are centrally located and exposed to pressure fluctuations from shut-off valve operations.
Innovation Solution
The integration of a low-pass filter arrangement, comprising a throttle and a smaller pressure vessel, connected between the pressure sensors and the connecting lines of the air springs, which dampens and filters out pressure peaks and fluctuations, ensuring that the measured air pressures accurately reflect the bellows pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pressure sensors are arranged centrally in the valve block, then installation effort is reduced and connectors are protected from dirt and splash water, but pressure measurements become inaccurate during dynamic pressure changes
Solution Approach 1:
A filter arrangement is introduced as an intermediary component between the pressure sensor and the connecting line. This filter arrangement includes a throttling element and a pressure equalization chamber that mediates the pressure transmission, allowing the sensor to be positioned centrally while still providing accurate measurements by filtering out harmful pressure fluctuations before they reach the sensor.
2Measurement precision
If pressure sensors are arranged near the air springs, then pressure measurements are accurate during dynamic changes, but installation effort increases and connectors are exposed to dirt and splash water
Solution Approach 1:
The filter arrangement serves as a protective intermediary that allows the pressure sensor to be positioned centrally in the valve block rather than near the air springs. This intermediary structure transmits pressure information accurately while protecting the sensor and its connectors from the harsh environment, eliminating the need for complex installation near the air springs.
3Productivity
If shut-off valves open and close rapidly, then ventilation and venting control is improved, but pressure peaks and fluctuations increase causing measurement errors
Solution Approach 1:
The filter arrangement with its pressure equalization chamber and throttling element provides beforehand cushioning for pressure peaks and fluctuations generated by rapid shut-off valve operations. The chamber absorbs sudden pressure changes and the throttle element dampens oscillations, cushioning the pressure sensor against harmful fluctuations before they can cause measurement errors.
Solution Approach 2:
The filter arrangement acts as a mediator between the rapid shut-off valve operations and the pressure sensor. It allows the shut-off valves to operate rapidly for improved ventilation control while simultaneously filtering out the resulting pressure peaks and fluctuations, preventing them from reaching the sensor and causing measurement errors.
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 solution allows for precise control of the ventilation and venting of air springs by accurately measuring bellows pressures, reducing the impact of pressure peaks and fluctuations, thereby improving the overall performance of the air suspension system.
Implementation Method 1
connected to the connecting line of the bellows of the associated air spring or bellows of the associated air springs via a filter arrangement, in particular a low-pass filter, acting as a low-pass filter
Implementation Method 2
The filter arrangements preferably consist of a throttle and a smaller pressure vessel, each arranged in series between the associated connecting line and the respective pressure sensor
Data Source
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AI summary
The invention relates to a sensor arrangement (1) for an air suspension system of a vehicle, which has a change-over valve (14) for each air spring (8a, 8b) of a vehicle axle (2) or of multiple, adjacent tandem axles, and has a shutoff valve (16a, 16b) for each air spring (8a, 8b) of each vehicle wheel (4a, 4b) of the vehicle axle (2) or for each air spring of each vehicle side of the tandem axles, and wherein: each change-over valve (14) and the shutoff valves (16a, 16b) are structurally combined in a valve block (12) disposed at a distance from the air springs (8a, 8b); for measuring the bellows pressure in each of the air-spring bellows (10a, 10b) of the air springs, the air suspension system has a respective pressure sensor (18a, 18b), said sensors being disposed in or on the valve block (12); and each pressure sensor is connected at the output of the shutoff valve (16a, 16b) associated with said sensor to the connection line (32a, 32b) of the air-spring bellows (10a, 10b) of the associated air spring, or the air-spring bellows of the associated air springs. Nevertheless, in order to measure, with a significant degree of precision, the bellows pressure (pB) in the air-spring bellows in spite of this disadvantageous arrangement of pressure sensors (18a, 18b), each pressure sensor is connected, via a filter arrangement (42a, 42b) acting as a low-pass filter, to the connection line of the air-spring bellows of the associated air spring, or to the air-spring bellows of the associated air springs.