Vehicle Compressor Clutch Torque Control for Startup Wear

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Solution Overview

Problem

Existing air conditioning systems for motor vehicles, particularly agricultural utility vehicles, face issues with compressor wear due to refrigerant and lubricant segregation during extended downtimes, leading to high loads and potential damage during startup.

Innovation Solution

A control device measures the elapsed compressor service life and adjusts the drive torque used to start the compressor, reducing wear by influencing the drive torque based on the determined time variable, allowing for a gentle and low-wear startup by adjusting the compressor clutch's frictional connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the compressor is started up after extended downtimes with fixed timing clutch engagement, then the compressor can be operated, but the compressor experiences high loads and increased wear due to refrigerant/lubricant segregation

Engineering Contradiction:
Improvecompressor reliabilityVSAvoidcompressor wear and damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The compressor clutch engagement is changed from a fixed timing pattern to a dynamic control strategy. The control device determines whether to engage the clutch immediately or delay engagement based on the elapsed compressor service life. This dynamic adaptation allows the system to optimize startup conditions, reducing wear during extended downtimes when lubricant segregation is more likely to occur.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of clutch engagement timing based on the elapsed service life of the compressor. By using a time variable (elapsed compressor service life) to determine the engagement strategy, the system adapts the startup parameters to the actual condition of the compressor, thereby reducing wear during periods of extended downtime.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the compressor clutch is engaged for a predetermined period regardless of actual conditions, then the compressor can be started, but the actual degree of refrigerant/lubricant segregation is disregarded leading to high loads

Engineering Contradiction:
Improvecompressor startupVSAvoidcompressor protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control device incorporates feedback by determining the elapsed compressor service life and using this information to decide on the clutch engagement strategy. This feedback mechanism allows the system to adapt the startup procedure based on the actual operating history and condition of the compressor, ensuring reliable operation while protecting against excessive wear.

Inventive Principle:
Principle #23Feedback

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

Ensures a gentle and low-wear startup of the compressor, even after extended downtimes, by reducing drive torque when lubricant segregation is significant, thereby minimizing wear and preventing damage.

Implementation Method 1

an electrically actuable compressor clutch can be arranged between the compressor and the drive unit of the motor vehicle, the adhesion of which can be adjusted by the control device

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2269849B1Method for controlling an air-conditioning unit for a vehicle
Publication Date: 2018.06.20 DEERE & CO
  • EP2269849B1 patent drawingFigure 1
  • EP2269849B1 patent drawingFigure 2

AI summary

The device has a cooling circuit filled with cooling agent and operated by a compressor (12). The cooling agent is transferred along with lubricant for lubricating the compressor. Drive moment required for starting the compressor is reduced with respect to a condition of determined time variable by a control device (30). The control device determines time factor based on detected time information, where the time factor indicates elapsed compressor service life. An electric operatable compressor coupling (22) is arranged between the compressor and a power supply unit.