Vehicular Air Conditioner Valve Switching After Compressor Stop
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Solution Overview
Problem
In conventional vehicular air conditioners, the compressor must be operated to generate differential pressure for switching a four-way valve, which is not feasible in electric trains where the power source disconnection causes the compressor to stop, leading to insufficient switching of the valve unit to a middle position.
Innovation Solution
A pressure accumulator is used to maintain differential pressure between piston rooms by accumulating coolant related to aspiration pressure, allowing the four-way valve to switch even after the compressor is stopped, with a low-pressure accumulator connected via a check valve to ensure continuous coolant flow and prevent valve unit stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the compressor is stopped due to power source disconnection, then energy consumption is reduced, but the differential pressure required for switching the four-way valve cannot be maintained causing the valve unit to stop at a middle position
Solution Approach 1:
The patent introduces an accumulator that pre-stores high-pressure coolant before the compressor stops. This preliminary accumulation of pressurized coolant ensures that when the compressor stops and power is disconnected, the stored high-pressure coolant can still provide the necessary differential pressure to reliably switch the four-way valve to the heating position, preventing the valve unit from stopping at a middle position.
Solution Approach 2:
The accumulator acts as an intermediary component between the compressor and the four-way valve. It receives and stores high-pressure coolant from the compressor, then releases this stored pressurized coolant to the piston room of the four-way valve when needed. This intermediary function allows the system to maintain differential pressure for valve switching even after the compressor has stopped operating due to power disconnection.
2Reliability
If the compressor is operated to generate differential pressure for switching the four-way valve, then the valve switching function is reliable, but the system cannot operate in electric trains where power source disconnection occurs
Solution Approach 1:
The accumulator pre-charges with high-pressure coolant during the period when power is available and the compressor is operating. This preliminary charging action allows the system to later switch to heating mode even after power disconnection, making the system adaptable to the intermittent power supply characteristics of electric trains.
Solution Approach 2:
The accumulator serves as a buffer intermediary that decouples the compressor operation from the four-way valve switching requirement. By storing pressurized coolant, it allows the valve to be switched reliably even when the compressor cannot operate due to power source disconnection, thereby enabling the system to adapt to electric train power systems.
3Reliability
If a pressure accumulator is added to maintain differential pressure after compressor stop, then valve switching reliability is improved, but device complexity increases
Solution Approach 1:
The accumulator is introduced as a relatively simple intermediary component that connects between the compressor discharge line and the four-way valve piston room. Despite adding one component, the overall system complexity remains manageable because the accumulator's function is straightforward (pressure storage) and it integrates seamlessly into the existing refrigerant circulation path without requiring complex control mechanisms.
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
The solution maintains the necessary differential pressure for switching the four-way valve, preventing it from being stuck in a middle position and enabling safe cooling and heating operations in vehicular air conditioners, even when the compressor is stopped.
Implementation Method 1
a low pressure accumulator is connected to a pipe, which passes the low pressure coolant which is aspirated to the compressor, via a check valve in which a flow direction is a direction for aspirating the coolant to the compressor
Implementation Method 2
a pressure accumulator is provided in which a coolant, which is related to the aspiration pressure of the compressor, is accumulated when the compressor is operated, and the differential pressure, which is required for switching the four-way valve, between the piston rooms is maintained
Data Source
AI summary
In a vehicular air conditioner in which a cooling operation and a heating operation are switched by switching a four-way valve, a pressure accumulator is provided in which a coolant, which is related to an aspiration pressure of a compressor, is accumulated when the compressor is operated, and a differential pressure, which is required for switching the four-way valve, between piston rooms is maintained, and the differential pressure, which is required for switching the four-way valve, is generated between the piston rooms of the four-way valve even after the compressor is stopped.