Vehicle Cooling Cycle Pressure Control for Compressor-Free Coolant Return

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Solution Overview

Problem

In vapor compression refrigeration cycles used for cooling in vehicles, the need to operate the compressor even when cooling is unnecessary increases the load and reduces overall efficiency, as coolant liquid must be returned from an accumulator to a receiver for reuse.

Innovation Solution

A cooling device with a compressor, heat exchangers, gas-liquid separating units, a decompressor, a switch valve, and a pressure regulating unit, where the switch valve allows liquid-phase coolant transfer between the units without compressor operation, and the pressure regulating unit adjusts pressure differences to optimize coolant transfer and reduce compressor load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the compressor is operated to return coolant liquid from the accumulator to the receiver for reuse, then the coolant can be recovered and reused for cooling, but the compressor load increases and overall efficiency decreases

Engineering Contradiction:
Improvecoolant recoveryVSAvoidcompressor load
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

A four-way valve is introduced as an intermediary device to redirect coolant flow paths. The valve enables the accumulator to connect directly to the receiver or to the evaporator inlet, allowing coolant liquid to be returned without requiring compressor operation. This mediator component resolves the contradiction by providing an alternative pathway that bypasses the energy-consuming compression process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of using the compressor to push coolant liquid back to the receiver (normal operation), the system inverts the approach by using the four-way valve to redirect coolant flow during specific operating conditions. This inversion allows coolant to return to the receiver through pressure differential and flow direction control rather than compression, eliminating the energy penalty while maintaining coolant recovery.

Inventive Principle:
Principle #13The other way round (Inversion)

2Quantity of substance

If the compressor is operated continuously to maintain pressure difference between receiver and accumulator, then coolant liquid can be transferred back to receiver, but the cooling efficiency is reduced due to unnecessary compressor operation

Engineering Contradiction:
Improvecoolant liquid transferVSAvoidcooling efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The four-way valve is dynamically controlled based on system conditions to switch between different coolant flow configurations. During cooling operation, the valve maintains normal flow paths for high cooling efficiency. During coolant recovery phases, the valve redirects flow to enable accumulator-to-receiver transfer without compressor operation. This dynamic switching allows the system to optimize for either cooling efficiency or coolant recovery depending on operational needs, rather than continuously compromising cooling efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses its own coolant pressure and the four-way valve configuration to accomplish coolant liquid transfer from accumulator to receiver without external energy input. The high-pressure coolant naturally flows through the redirected path when the valve is positioned appropriately, enabling self-service coolant recovery that does not require the energy-intensive compressor operation.

Inventive Principle:
Principle #25Self-service

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 configuration reduces the compressor load and improves cooling efficiency by allowing coolant liquid transfer without compressor operation and maintaining optimal pressure differences, enhancing the overall efficiency of the vapor compression refrigeration cycle.

Implementation Method 1

a first heat exchanger (condenser) configured to perform heat exchange between the coolant having been compressed and outside air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a first gas-liquid separating unit configured to separate the coolant having been subjected to the heat exchange by the first heat exchanger into gas and liquid

Methodology Applied
Scientific EffectGas-liquid separation: Density Gradient

Implementation Method 3

a decompressor configured to decompress the coolant from the first gas-liquid separating unit

Methodology Applied
Scientific EffectDecompression: Depressurisation

Implementation Method 4

a second heat exchanger (evaporator) configured to perform heat exchange between the coolant having been decompressed and air-conditioning air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 5

a second gas-liquid separating unit configured to separate the coolant having been subjected to the heat exchange by the second heat exchanger into gas and liquid, and supply the coolant to the compressor

Methodology Applied
Scientific EffectGas-liquid separation: Density Gradient

Data Source

PatentEP2818808B1Cooling device, vehicle provided with same, and control method for cooling device
Publication Date: 2016.12.21 TOYOTA JIDOSHA KK
  • EP2818808B1 patent drawingFigure 1
  • EP2818808B1 patent drawingFigure 2
  • EP2818808B1 patent drawingFigure 3~4

AI summary

A cooling device (200) utilizes a vapor compression refrigeration cycle including a compressor (210), a condenser (220), a receiver (230), an expansion valve (260), an evaporator (240), and an accumulator (250) to cool a heat source (110, 120) with a coolant. The receiver (230) separates the coolant having been subjected to heat exchange by the condenser (220) into gas and liquid. The accumulator (250) separates the coolant having been subjected to heat exchange by the evaporator (240) into gas and liquid. The cooling device (200) opens a switch valve (270) capable of bringing the receiver (230) and the accumulator (250) into communication with each other to move the coolant liquid in the accumulator (250) to the receiver (230). The cooling device (200) restores the pressure difference between the receiver (230) and the accumulator (250) after the movement of the coolant liquid to the pressure difference before the movement of the coolant liquid by a pressure regulating unit (350).