EV Air Conditioning Fog Suppression via Low Voltage Battery

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Solution Overview

Problem

Electric vehicle air-conditioning devices face challenges in reducing power consumption from high voltage batteries while preventing windshield fogging, especially when the electric compressor is stopped, leading to user discomfort due to functional restrictions.

Innovation Solution

An air-conditioning device with a refrigeration circuit, an interior/exterior air switching device, and a fog suppressor, which switches to an exterior-air mode and operates using low voltage battery power when the vehicle is in a power-restricted state, ensuring the electric compressor is stopped to conserve high voltage battery power and suppress fogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the electric compressor is stopped to reduce power consumption from the high voltage battery, then power consumption is reduced, but windshield fogging occurs and user comfort deteriorates

Engineering Contradiction:

Improvepower consumption from high voltage batteryVSAvoidwindshield fogging

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system divides the fog suppression function into two independent parts: the electric compressor (high voltage) and the fog suppressor (low voltage). When the high voltage battery is restricted, only the fog suppressor using low voltage battery power operates to prevent fogging, while the electric compressor stops to conserve high voltage power.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The low voltage battery acts as an intermediary power source that takes over the fog suppression function when the high voltage battery is restricted. The fog suppressor, powered by the low voltage battery, mediates between the power restriction and the need to prevent windshield fogging.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the defroster outlet port is opened to suppress fogging, then windshield fogging is reduced, but power consumption increases and user comfort deteriorates due to excessive air flow

Engineering Contradiction:

Improvewindshield foggingVSAvoiduser comfort

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The fog suppressor provides localized fog prevention directly at the windshield area without requiring full-cabin air circulation. This targeted approach suppresses fogging effectively while consuming minimal power and avoiding excessive air flow that would reduce user comfort.

Inventive Principle:

Principle #3Local quality

3Use of energy by moving object

If the electric compressor is stopped to conserve high voltage battery power, then power consumption is reduced, but the air-conditioning device functionality is restricted causing user discomfort

Engineering Contradiction:

Improvepower consumption from high voltage batteryVSAvoidair-conditioning device functionality

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The fog suppression function is extracted from the electric compressor system and implemented as a separate fog suppressor device powered by the low voltage battery. This extraction allows the air-conditioning device to maintain essential fog suppression functionality even when the electric compressor is stopped due to power restrictions.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution effectively reduces power consumption from high voltage batteries, suppresses windshield fogging, and maintains user comfort by using low voltage battery power for fog suppression even when the electric compressor is stopped, ensuring efficient energy use and comfort during power restrictions.

Implementation Method 1

air containing water-vapor evaporated from an evaporator

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 2

a fog suppressor suppressing fogging of a windshield

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS10131197B2Electric vehicle air-conditioning device

Publication Date: 2018.11.20 DENSO CORP

AI summary

When a battery control unit allows use of the electric compressor, an air conditioning control unit performs air-conditioning of a cabin in such a manner that the air conditioning control unit controls the electric compressor to be operated. When the battery control unit prevents use of the electric compressor, the air conditioning control unit controls the electric compressor to be stopped. In addition, the air conditioning control unit heats a windshield in such a manner that the air conditioning control unit controls a window heater to be operated. Accordingly, even when the electric compressor is stopped, fogging of the windshield is suppressed. The air conditioning control unit does not give an excessive feeling of discomfort or unease to a user, because the air conditioning control unit continuously performs a normal air-conditioning control. Fogging of the windshield can be suppressed in a state where power consumption relative to a battery is suppressed.