Vehicle Relay Dehumidifier Using Dry Air to Prevent Contact Freezing
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Solution Overview
Problem
Mechanical relays in vehicles experience contact freezing due to humidity buildup in the relay housing, leading to poor electrical conductivity, especially in low-temperature environments.
Innovation Solution
A relay dehumidifier system that includes a relay housing connected to a negative pressure source and an evaporator via communication pipes, utilizing a solenoid valve and check valve to control air flow, ensuring dry air is introduced into the relay housing when conditions are favorable, thereby maintaining low humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a through hole is provided on the relay housing to discharge humid air, then humidity can be reduced, but wet air can enter from the through hole causing condensation and freezing
Solution Approach 1:
A valve is introduced as an intermediary component between the relay housing and the external environment. The valve selectively controls air flow: it opens to allow dry air intake when evaporator outlet humidity is low, and closes to prevent humid air entry when evaporator outlet humidity is high, thus mediating between dehumidification needs and contact protection
Solution Approach 2:
The valve processor monitors the humidity at the evaporator outlet and uses this feedback to control valve operation. When humidity is low, the valve opens for dry air intake; when humidity is high, the valve closes to prevent condensation, creating a closed-loop feedback control system
2Quantity of substance
If the valve is opened continuously to discharge humid air, then dehumidification is improved, but the risk of wet air entering and causing contact freezing increases
Solution Approach 1:
Instead of continuous operation, the valve operates periodically based on evaporator outlet humidity conditions. The valve opens during periods when dry air is available (low humidity at evaporator outlet) and closes during periods when humid air might enter, creating a periodic dehumidification cycle that avoids contact freezing
Solution Approach 2:
The valve acts as a conditional intermediary that mediates between the need for dehumidification and the need to prevent humid air entry. It selectively permits air flow only when conditions are favorable (low evaporator outlet humidity), blocking the path when conditions are unfavorable
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
Effectively suppresses moisture condensation and contact freezing by periodically scavenging the relay housing with dry air, ensuring reliable electrical contact performance even in humid conditions.
Implementation Method 1
a negative pressure source, the valve processor is configured to open the valve when: the negative pressure source generates a negative pressure
Implementation Method 2
an evaporator... a humidity of an outlet of the evaporator is equal to or less than a predetermined value
Data Source
AI summary
A relay dehumidifier for a vehicle includes a relay housing, a valve, and a valve processor. The relay housing houses a mechanical relay body, and communicates individually with each of a negative pressure source and an evaporator. The valve is disposed at a first communication pipe. The first communication pipe communicates the negative pressure source and the relay housing with each other. The valve processor is configured to control an opening and closing operation of the valve. The valve processor is configured to close the valve in a normal state, and open the valve when: the negative pressure source generates a negative pressure; and a humidity of an outlet of the evaporator is equal to or less than a predetermined value.