Gas Injection A/C Switching Control for Fast Compressor Restart
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Solution Overview
Problem
Electric vehicle air conditioners with gas injection cycles face issues with compressor restarts due to backward rotation caused by pressure differences, leading to prolonged waiting periods and uncomfortable temperatures in the vehicle compartment.
Innovation Solution
Incorporating a switching device and controller to switch from a two-stage compression mode to a single-stage compression mode before stopping the compressor, allowing the refrigerant to flow out and reducing pressure differences, thereby preventing backward rotation and enabling quicker compressor restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the electric compressor is operated in two-stage compression mode with gas injection, then heating performance under super-cold environment is improved, but compressor restart time increases due to backward rotation
Solution Approach 1:
The control device switches the refrigerant circuit from two-stage compression mode to single-stage compression mode before stopping the compressor. This preliminary action equalizes the pressure between the intermediate port and suction port, preventing backward rotation when the compressor restarts, thereby reducing restart time while maintaining heating performance capability
2Use of energy by moving object
If the electric compressor is temporarily stopped during heating operation, then power can be allocated to other vehicle devices, but refrigerant flows backward causing compressor to rotate backward
Solution Approach 1:
Before stopping the compressor for power reallocation, the control device switches to single-stage compression mode to equalize pressures. This preliminary pressure equalization prevents backward rotation when the compressor restarts after power reallocation, maintaining operational simplicity
Solution Approach 2:
The patent replaces mechanical pressure equalization methods with electronic control of the refrigerant circuit configuration. By using electronic switching between compression modes, the system achieves pressure equalization without mechanical modifications to the compressor itself
3Productivity
If the compressor is restarted while rotating backward, then immediate heating resumption is possible, but the electric compressor fails to restart properly
Solution Approach 1:
The control device performs preliminary pressure equalization by switching to single-stage compression mode before stopping the compressor. This ensures that when the restart signal is received, the compressor can immediately restart in two-stage mode without attempting to restart while rotating backward, maintaining both reliability and productivity
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 reduces the duration of compressor stoppage and restart time, maintaining a comfortable temperature in the vehicle compartment by preventing backward rotation and ensuring prompt compressor reactivation.
Implementation Method 1
the compression mechanism compresses the low-pressure refrigerant to be a high-pressure refrigerant
Implementation Method 2
The radiator performs a heat exchange between the air and the refrigerant discharged by the discharge port and makes the refrigerant to radiate heat
Implementation Method 3
The first pressure reducer reduces a pressure of refrigerant flowing out of the radiator to be the intermediate-pressure refrigerant
Implementation Method 4
The gas-liquid separator separates the intermediate-pressure refrigerant, which flows from the first pressure reducer, into a gas-phase refrigerant and a liquid-phase refrigerant
Implementation Method 5
The second pressure reducer reduces a pressure of the liquid-phase refrigerant separated in the gas-liquid separator to be the low-pressure refrigerant
Implementation Method 6
The exterior heat exchanger performs a heat exchange between an outside air from an outside the vehicle compartment and the refrigerant flowing out of the second pressure reducer and evaporates the refrigerant
Data Source
AI summary
An air conditioner for a vehicle has a compressor, a radiator, a first pressure reducer, a gas-liquid separator, a second pressure reducer, an exterior heat exchanger, an intermediate pressure refrigerant passage, a switching device, and a controller. The controller operates the switching device to switch from a refrigerant circuit of a two-stage compression mode to a refrigerant circuit of a single-stage compression mode when a compressor stop signal is output in the two-stage compression mode. The single-stage compression mode is a mode that blocks at least a flow of an intermediate-pressure refrigerant into the intermediate pressure refrigerant passage and makes refrigerant remained in the intermediate pressure refrigerant passage to flow out of the intermediate pressure refrigerant passage. The controller stops the compressor after controls the compressor to continue operating for a specified time in the single-stage compression mode. The controller restarts the compressor when the compressor stop signal is canceled.