Vehicle Heat Pump Compressor Control for Frost Management
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Solution Overview
Problem
In air-conditioning systems for vehicles, the efficiency of heat exchange is compromised when frost forms on outdoor heat exchangers, leading to decreased heating capability and excessive power consumption due to the auxiliary heating means, such as PTC heaters, generating more heat than the radiator, causing the radiator to absorb heat instead of radiating it.
Innovation Solution
A control system that monitors the refrigerant temperatures and heating capabilities within the air-conditioning apparatus, stopping the compressor when specific conditions indicate inefficient heat exchange, and adjusts the operation of the auxiliary heating means to maintain comfortable interior temperatures while minimizing power wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the auxiliary heating means (PTC heater) is disposed on the air upstream side of the radiator, then the heating efficiency is improved when air temperature is low, but the radiator absorbs heat instead of radiating heat when the auxiliary heating capability exceeds the radiator heating capability
Solution Approach 1:
The control unit monitors the heating capability of the radiator and the auxiliary heating means, and adjusts or stops the compressor operation based on their relationship to prevent the radiator from absorbing heat when auxiliary heating capability exceeds radiator heating capability
Solution Approach 2:
The system dynamically adjusts the compressor operation based on real-time heating capability assessment, transitioning between different operational states to optimize heating efficiency and prevent energy loss
2Temperature
If the compressor operates continuously to maintain heating capability, then the heating performance is maintained, but power consumption increases excessively when heat exchange efficiency deteriorates
Solution Approach 1:
The control unit continuously monitors heat exchange efficiency and heating capability, adjusting compressor operation accordingly to stop the compressor when inefficient heat exchange is detected, thereby reducing power consumption while maintaining necessary heating performance
Solution Approach 2:
The system uses its own monitoring capabilities to detect inefficient heat exchange conditions and automatically adjusts compressor operation to optimize power consumption
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 control system effectively reduces power consumption and ensures comfortable vehicle heating by stopping the compressor when inefficient heat exchange occurs, preventing the radiator from absorbing heat and maintaining the auxiliary heating's temperature effectiveness.
Implementation Method 1
a compressor (2) to compress a refrigerant
Implementation Method 2
a radiator (4) disposed in an air flow passage (3) to let the refrigerant radiate heat
Implementation Method 3
an outdoor heat exchanger (7) disposed outside the vehicle interior to let the refrigerant absorb heat
Implementation Method 4
a positive temperature coefficient (PTC) heater is often employed in such an auxiliary heating means
Data Source
AI summary
In an air-conditioning apparatus of a so-called heat pump system, wasteful power consumption to be generated when an auxiliary heating means is disposed on an air upstream side of a radiator is decreased, and comfortable heating of a vehicle interior is also achieved. The air-conditioning apparatus includes an electric heater 57 disposed on an upstream side of air flowing through an air flow passage 3 to a radiator 4, and a controller executes a cooperative operation of heating air to be supplied to the vehicle interior by the electric heater 57 and the radiator 4, and stops a compressor 2 on the basis of establishment of a condition that an inlet refrigerant temperature Tcxin of the radiator is lower than an outlet refrigerant temperature TCI of the radiator (Tcxin<TCI).