Pneumatic Suspension Air Mass Flow Control
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Solution Overview
Problem
Existing air suspension systems for motor vehicles have limited control over air mass flow when spring bellows are inflated and deflated, resulting in insufficient control over the raising and lowering speed of the vehicle body, which is either inadequately achieved with functional disadvantages or requires high equipment costs.
Innovation Solution
The system connects spring bellows in parallel to a main pressure line via additional connection lines with second level control valves and throttles, allowing for different air mass flows and raising/lowering speeds by adjusting the opening of these valves, with the throttles downstream determining the air mass flow and enabling three-stage control of air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional connection lines with second level control valves and throttles are added to control air mass flow, then the control precision of raising and lowering speeds is improved, but the device complexity increases
Solution Approach 1:
The system divides the air supply path into multiple parallel connection lines, each with its own level control valve and throttle. This segmentation allows independent control of air mass flow to different spring bellows, enabling precise control of raising and lowering speeds without requiring a single complex control mechanism.
Solution Approach 2:
The system uses adjustable throttles with variable opening degrees in parallel connection lines to dynamically control air mass flow. By adjusting the opening degree of throttles, the system can adaptively control the raising and lowering speeds of the vehicle body, providing dynamic control precision without fixed complex mechanisms.
2Adaptability or versatility
If complex control mechanisms are used to precisely control air mass flow, then the controllability of air suspension system is improved, but the manufacturing cost increases
Solution Approach 1:
The system uses multiple simple parallel connection lines with basic level control valves and adjustable throttles instead of a single complex control mechanism. This segmented approach achieves versatile control of air mass flow and improves controllability while keeping individual components simple and cost-effective to manufacture.
Solution Approach 2:
The system controls air mass flow by changing the opening degree parameter of adjustable throttles in parallel connection lines. This parameter-based control method provides versatile controllability of raising and lowering speeds without requiring complex mechanical structures, thereby reducing manufacturing costs.
3Productivity
If larger throttle cross-sectional areas are used, then the air mass flow rate is improved, but the raising and lowering speed control precision is worsened
Solution Approach 1:
The system divides the air flow path into multiple parallel connection lines, each with its own throttle. This allows the total air mass flow rate to be increased through multiple pathways while each individual throttle can be sized appropriately for precise speed control, resolving the contradiction between flow rate and control precision.
Solution Approach 2:
The system uses adjustable throttles that can dynamically change their effective cross-sectional area. This allows the system to provide large air mass flow rates when needed while maintaining the ability to precisely control raising and lowering speeds by adjusting the opening degree, thus resolving the contradiction between productivity and control precision.
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 configuration allows for simple and cost-effective control of air mass flow, enabling precise adjustment of raising and lowering speeds of the vehicle body, reducing the need for complex and expensive components, and improving the controllability of the air suspension system.
Implementation Method 1
one of the second level control valves is followed by a throttle whose throttle cross-sectional area is smaller than the nozzle cross-sectional area of the second level control valve
Data Source
Figure 1
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AI summary
The invention relates to a pneumatic suspension system (1a, 1b, 1e) of a motor vehicle, comprising a plurality of spring bellows (23, 24) that are associated with the pneumatic springs of at least one vehicle axle, can be connected by means of the respective linking leads (29, 30) that are each provided with a level control valve (25, 26) to a main pressure line (22), and can be shut off with respect to same, wherein the main pressure line (22) can be connected by means of at least one associated valve (3, 6, 10, 34) alternately to a compressed air source and a compressed air sink and can be shut off with respect to same. According to the invention, in order to set different flow rates of the air mass flow in a simple and cost-effective manner when air is supplied to and removed from the spring bellows (23, 24), the spring bellows (23; 24) of the pneumatic springs arranged at least on a vehicle axle or on a vehicle side can be respectively connected to the main pressure line (22) in parallel with the first connecting lines (29; 30) at least by means of a second connecting line (31; 32) provided with a second level control valve (27; 28) and can be shut off with respect to said main pressure line. The second level control valves (27; 28) of the relevant spring bellows (23; 24) each have nozzle cross-sectional surfaces (NWX = NWY) of the same size as the first level control valve (25; 26), and a choke (51; 52) is connected downstream of each of the second level control valves (27; 28) in the ventilation direction, the cross-sectional surfaces (NWD) of said chokes being smaller than the nozzle cross-sectional surface (NWY) of the relevant second level control valve (27; 28) (NWD < NWY).