Pneumatic Suspension Control for Energy Efficiency
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Solution Overview
Problem
Existing systems for adjusting pneumatic suspension in heavy vehicles face challenges in efficiently managing energy consumption and maintaining adequate pressure levels, particularly in elevating the cut-out pressure level, which results in a small pressure span and non-optimal charging of the pressure buffer, affecting fuel economy.
Innovation Solution
A system with sensors and a control unit that monitor the position relationship between the chassis element and wheel pairs, comparing measured values to target values and pressure limits, allowing for intelligent control of system pressure to maintain energy efficiency and adequate pressure buffering by selecting optimal compressor operation instances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the cut-out pressure level is elevated to ensure adequate pressure for vehicle functions, then the system pressure is improved, but the pressure span between cut-in and cut-out levels becomes small, making it difficult to select optimal instances for charging the pressure buffer
Solution Approach 1:
The control unit predicts future demand for pneumatic pressure and proactively charges the pressure buffer in advance during periods of low demand. This preliminary action ensures adequate pressure is available when needed without requiring a large pressure span, as the buffer is filled during off-peak periods.
Solution Approach 2:
The system dynamically adjusts the cut-in and cut-out pressure levels based on predicted future demand and current buffer status. Rather than using fixed pressure levels, the control unit varies these thresholds to optimize the pressure span available for buffer charging, adapting to changing vehicle operating conditions.
2Reliability
If the compressor is operated frequently to maintain pressure buffer at optimal levels, then the pressure buffer management is improved, but the energy consumption increases, affecting fuel economy
Solution Approach 1:
The control unit predicts future demand and charges the pressure buffer in advance during periods when compressor operation is more efficient (e.g., during engine braking or low demand periods). This avoids frequent compressor operations at suboptimal times and reduces overall energy consumption while maintaining reliable buffer management.
Solution Approach 2:
The control unit continuously monitors the pressure buffer status, current system pressure, and vehicle operating conditions. This feedback enables intelligent decision-making about when to operate the compressor, charging the buffer only when it is energetically advantageous and when future demand predicts it will be utilized, thereby minimizing unnecessary energy consumption.
3Stress or pressure
If the cut-in pressure level is elevated to ensure adequate pressure, then the system pressure is improved, but the pressure span becomes small, requiring frequent compressor operations at non-optimal instances
Solution Approach 1:
The system performs preliminary charging of the pressure buffer during periods of low demand or during engine braking when compressor operation is energetically favorable. This advance preparation eliminates the need for frequent compressor operations at non-optimal instances, improving both system pressure reliability and fuel economy.
Solution Approach 2:
The control unit dynamically changes the cut-in and cut-out pressure levels based on predicted future demand and current buffer status. By adjusting these parameters rather than using fixed elevated levels, the system maintains adequate pressure while optimizing the pressure span for efficient buffer charging, thereby improving fuel economy.
Data Source
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Figure 4
AI summary
The present invention relates to automatic adjustment of a position relationship between a motor vehicle's (110) chassis element (119) and at least one wheel pair (113; 114a, 114b) of the vehicle (110). A control unit (117) receives a target value (hT) and a measured value (h) expressing the position relationship between the chassis element (119) and the at least one wheel pair (113; 114a, 114b). Based thereon, the control unit (117) produces a first control signal (C1), which influences an input air flow from a pneumatic pressure source system (115; 116) to a pneumatically operated control mechanism, such that the a position relationship is varied. The pressure source system (115; 116) produces a system pressure (PS), and a pressure sensor means (111) registers a pressure parameter indicative of the system pressure (PS). Furthermore, the control unit (117) compares the measured value (h) with the target value (hT), compares the system pressure (PS) with at least one pressure limit (Pco1; Pco2 ), investigates whether one of at least two decision criteria is fulfilled. Upon fulfillment of such a criteria, the control unit (117) controls the system pressure (PS) to a predefined level by means of a second control signal (C2). The predefined level depends on which decision criterion that is fulfilled.