Compressed Air Dryer Control Using Dew Point Feedback

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Solution Overview

Problem

Existing compressed air supply systems in commercial vehicles face challenges in achieving high dryer performance while minimizing energy consumption, as the current control methods often result in energy losses due to prolonged regeneration phases.

Innovation Solution

The proposed solution involves a procedure and a compressed air supply device that dynamically adjust the number and length of regeneration phases based on the current and target dew point depression (DPD) values, allowing for optimized energy efficiency and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If long regeneration phases are used to ensure high dryer performance and prevent moisture condensation, then the dew point depression is sufficient, but energy consumption increases

Engineering Contradiction:
Improvedew point depressionVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the regeneration phase duration variable rather than fixed. The control system dynamically adjusts the length of regeneration phases based on real-time monitoring of dew point depression values and ambient conditions, allowing the system to extend regeneration only when necessary to achieve sufficient moisture removal while minimizing energy consumption during periods of lower humidity demand.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control by continuously measuring the dew point depression and using this information to regulate the regeneration process. The control system receives feedback on the actual dew point depression achieved and adjusts subsequent regeneration phases accordingly, ensuring that regeneration continues only until the required dew point depression is reached, thereby avoiding unnecessary energy expenditure.

Inventive Principle:
Principle #23Feedback

2Reliability

If frequent regeneration phases are implemented to maintain dryer performance, then moisture removal is effective, but energy loss increases

Engineering Contradiction:
Improvemoisture removal efficiencyVSAvoidenergy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The control system uses feedback from dew point depression measurements to determine when regeneration is actually needed. By monitoring the moisture content and dew point depression in real-time, the system can extend the interval between regeneration phases when moisture levels are low, thereby reducing the frequency of regeneration events and associated energy losses while still maintaining effective moisture removal when required.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transforms the regeneration process from a continuous or fixed-period operation to a variable periodic action. Instead of performing regeneration at fixed intervals regardless of condition, the system implements periodic regeneration only when monitoring data indicates that dew point depression has fallen below acceptable thresholds, optimizing the balance between moisture removal effectiveness and energy conservation.

Inventive Principle:
Principle #19Periodic action

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 enables a balance between achieving sufficient dryer performance to prevent moisture condensation and minimizing energy consumption by adapting regeneration phases according to real-time moisture levels and ambient conditions.

Implementation Method 1

a subsequent air dryer unit that cleans and dries the supplied compressed air

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

a compressor that draws in and compresses air

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4552936A1Method for controlling a compressed air supply device and compressed air supply device for a compressed air system of a commercial vehicle
Publication Date: 2025.05.14 ZF CV SYST GLOBAL GMBH
  • EP4552936A1 patent drawingFigure 1
  • EP4552936A1 patent drawingFigure 2~4
  • EP4552936A1 patent drawingFigure 5

AI summary

The invention relates to a method for controlling a compressed air supply unit of a compressed air system of a commercial vehicle and to such a compressed air system. The compressed air supply unit comprises a compressor, an air dryer unit, and a regeneration valve unit and is operated in a mode with delivery phases and regeneration phases. It is provided that the compressed air system maintains a current humidity level, e.g.,A relative or absolute humidity is determined; from this determined humidity, a current dew point reduction (c-DPD) is calculated; a target dew point reduction (t-DPD) is calculated from current and/or projected ambient temperature data (TO, T(t)) and/or from current and/or projected vehicle operating data; and subsequently, a target dew point reduction (t-DPD) is calculated from current and/or projected ambient temperature data (T0, T(t)) and compared with the current dew point reduction (c-DPD). The operating mode and/or regeneration phases are then set and/or changed based on this comparison.