Heat Pump Accumulator Bypass for Lower Refrigerant Pressure Drop
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Solution Overview
Problem
Heat pump systems in vehicles experience pressure drops due to accumulators, which can reduce efficiency and performance, particularly in high ambient temperatures and fast charging conditions.
Innovation Solution
A selectable bypass flow path is introduced to bypass the accumulator, using a three-way valve or shutoff valve to reroute refrigerant, reducing pressure drops and enhancing cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant flows through the accumulator, then oil pickup is maintained, but pressure drop increases
Solution Approach 1:
The system divides the refrigerant flow path into two separate paths: one through the accumulator for oil pickup and another bypassing the accumulator to avoid pressure drop. The three-way valve enables selective routing of refrigerant between these segmented paths based on operational conditions.
Solution Approach 2:
The three-way valve dynamically switches the refrigerant flow configuration between different modes (through-accumulator mode and bypass mode) based on real-time conditions such as ambient temperature and vehicle operation state, allowing the system to adaptively optimize between oil pickup and pressure drop concerns.
2Productivity
If bypass flow path is used, then pressure drop is reduced and cooling performance is enhanced, but oil pickup may be compromised
Solution Approach 1:
The system periodically switches between bypass mode (for cooling performance) and through-accumulator mode (for oil pickup) during fast-charging operation. The control mechanism implements periodic transitions to ensure both cooling efficiency and adequate oil return to the compressor are maintained over time.
Solution Approach 2:
The system changes operational parameters by switching the flow configuration through the three-way valve, transitioning between different flow paths based on temperature conditions and charging state, thereby optimizing the balance between cooling performance and oil pickup.
3Adaptability or versatility
If three-way valve is added, then flow path switching capability is improved, but device complexity increases
Solution Approach 1:
The three-way valve serves multiple functions: it routes refrigerant through the accumulator for oil pickup, bypasses the accumulator for reduced pressure drop, and enables transitions between these modes. This single component provides versatile flow control capability that would otherwise require multiple separate valves or complex piping arrangements.
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 bypass flow path reduces refrigerant pressure drops, providing a cooling boost to vehicle compartments and batteries, especially in high ambient temperatures and fast charging scenarios, while maintaining efficient oil pickup for the compressor.
Implementation Method 1
reduce or avoid a pressure drop in the refrigerant due to the accumulator
Implementation Method 2
an evaporator to provide cooling for a passenger compartment of the vehicle
Implementation Method 3
a compressor to compress the refrigerant
Data Source
AI summary
Aspects of the disclosure relate to a heat pump system having a selectable bypass flow path that allows a refrigerant to bypass an accumulator of the heat pump system. The bypass flow path may be used, for example, to reduce a pressure drop in a refrigerant, and may provide a cooling boost for a passenger compartment of a vehicle, particularly in high ambient temperature and/or solar load environments and/or during fast charging of a vehicle battery.