Segmented Vehicle Evaporator for High Cooling Capacity

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Solution Overview

Problem

Conventional air conditioning devices for vehicles face challenges in achieving high cooling capacity without increasing noise pollution, as they often rely on increasing fan operation to enhance cooling air flow, leading to noise discomfort, and are prone to evaporator icing issues at low temperatures.

Innovation Solution

The air conditioning device employs a split evaporator with two segments that can operate independently, allowing one segment to operate below freezing for high cooling capacity and switching to defrost mode when icing occurs, or uses a dehumidification evaporator upstream to prevent icing, and incorporates a sorbent unit for dehumidification, along with control strategies to manage operating modes based on monitored parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fan speed is increased to boost cooling air flow velocity, then cooling capacity is improved, but noise level increases

Engineering Contradiction:
Improvecooling capacityVSAvoidnoise level
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The evaporator is divided into multiple independently operable segments. This allows the system to optimize cooling efficiency without requiring high fan speeds, as the segmented design improves heat exchange effectiveness. The patent states that the evaporator comprises 'at least two independently operable evaporator segments', enabling selective operation that enhances cooling capacity while maintaining lower airflow velocities and reducing noise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operating temperature parameter of the evaporator to below 0°C, which fundamentally alters the heat exchange mechanism. This parameter change enables more efficient cooling per unit of airflow, allowing the system to achieve high cooling capacity without increasing fan speed. The patent specifies 'operable at an operating temperature of less than 0°C', which transforms the thermal efficiency of the system.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If evaporator operates at low temperature for high cooling capacity, then cooling performance is improved, but evaporator icing occurs

Engineering Contradiction:
Improvecooling capacityVSAvoidevaporator icing
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The evaporator is segmented into multiple independently operable sections. When icing is detected in one segment, the system can switch to another segment that remains free of ice, ensuring continuous reliable operation. The patent describes 'at least two independently operable evaporator segments' that can be controlled separately, allowing the system to bypass iced segments and maintain cooling function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements periodic defrost cycles where evaporator segments are alternately operated and defrosted. During defrost mode, a segment is heated to melt accumulated ice, then switched back to cooling mode. This periodic alternation prevents permanent icing buildup and maintains system reliability. The patent mentions switching between 'evaporation mode' and 'defrost mode' for different segments.

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 maintains high cooling capacity while reducing noise and preventing evaporator icing, ensuring consistent climate comfort by efficiently managing evaporator operation and defrosting, thus enhancing overall air conditioning performance.

Implementation Method 1

the evaporator has two independently operable evaporator segments through which the cooling air flows parallel to each other

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

The cooled and expanded refrigerant then passes through an evaporator, where it changes from a liquid to a gaseous state

Methodology Applied
Scientific EffectEvaporative cooling: Evaporative Cooler

Implementation Method 3

a dehumidification evaporator, also designed as a refrigerant/air heat exchanger and operated at a working temperature of more than 0°C, is fluidically connected upstream of the evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

incorporates a sorbent unit for dehumidification

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3003747B1Air-conditioning system for a motor vehicle and method for operating said air-conditioning system
Publication Date: 2020.02.19 VOLKSWAGEN AG
  • EP3003747B1 patent drawingFigure 1~3
  • EP3003747B1 patent drawingFigure 4

AI summary

The invention relates to an air-conditioning system for a motor vehicle, comprising a refrigerant circuit having at least one evaporator (16) configured as a refrigerant-air heat exchanger by means of which cooling air can be blown into an interior space of the motor vehicle by means of an air flow generating unit (12). The invention is characterized in that the evaporator (16) can be operated at a working temperature of less than 0°C.