Vehicle Ventilation Bypass Duct for Refrigerant Leak Safety
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Solution Overview
Problem
The use of flammable refrigerants like HFO-1234 in vehicle air conditioners poses a risk of refrigerant leakage into the vehicle cabin, which can lead to fires, and stopping the air conditioner to prevent this also stops ventilation, leaving no air circulation.
Innovation Solution
A ventilation and air conditioning apparatus with a ventilator that sucks outside air and connects it to the air conditioner through a duct system, including a bypass duct that allows fresh outside air to be supplied to the vehicle even if the air conditioner is stopped, ensuring continuous ventilation while preventing refrigerant leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air conditioner operation is stopped to prevent refrigerant leakage into the cabin, then safety is improved, but ventilation in the cabin is stopped
Solution Approach 1:
The duct system is segmented into multiple independent pathways: a first duct for conditioned air supply, a second duct for return air, a third duct for exhaust air, and a fourth duct serving as a bypass for fresh air. This segmentation allows the fresh air duct to operate independently when the air conditioner is stopped, maintaining ventilation while preventing refrigerant leakage through the closed air conditioner.
Solution Approach 2:
The fourth duct (bypass duct) acts as an intermediary pathway that provides an alternative route for fresh air to reach the cabin when the primary air conditioning pathway is closed. This bypass duct connects the fresh air intake to the cabin independently of the air conditioner, ensuring continuous ventilation even when the air conditioner is stopped for safety reasons.
2Object-affected harmful factors
If flammable refrigerant HFO-1234 is used in the air conditioner, then global warming potential is reduced, but the risk of refrigerant leakage and fire in the cabin increases
Solution Approach 1:
The harmful function of the air conditioner (potential refrigerant leakage) is extracted and isolated by providing a separate bypass pathway. The fourth duct allows fresh air to bypass the air conditioner entirely, extracting the ventilation function from the potentially harmful air conditioning system while maintaining the beneficial low GWP refrigerant usage.
Solution Approach 2:
The potential harm of stopping the air conditioner (loss of ventilation) is converted into a benefit by utilizing the stopped air conditioner's safety advantage (no refrigerant leakage) while compensating for the ventilation loss through the bypass duct system. The harmful refrigerant leakage risk is eliminated while the beneficial ventilation function is maintained through the alternative pathway.
3Productivity
If a bypass duct is added to enable continuous fresh air supply, then ventilation is maintained, but device complexity increases
Solution Approach 1:
The fourth duct (bypass duct) serves multiple functions: it provides a backup ventilation pathway when the air conditioner is stopped, offers an alternative route during normal operation to potentially improve air flow distribution, and maintains cabin pressure balance. This multi-functionality justifies the additional duct while providing more than just a simple bypass capability.
Data Source
AI summary
A ventilation and air conditioning apparatus for a vehicle includes: a ventilator that sucks air from outside the vehicle; an air conditioner that conditions air inside the vehicle; a duct for fresh outside air that connects the ventilator with the air conditioner so as to supply the air that the ventilator has sucked from outside the vehicle to the air conditioner; and a duct for conditioned air that supplies the conditioned air blown out from the air conditioner to inside the vehicle. The duct for fresh outside air is branched so as to be connected to the duct for conditioned air. With this configuration, even if the operation of the air conditioner is stopped due to, e.g., a leakage of a flammable refrigerant, an amount of ventilation can be secured in the vehicle.