Vehicle Heat Pump Heating Control to Prevent Outdoor Coil Frost
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Solution Overview
Problem
In heating modes of vehicular air-conditioning systems, frost formation on outdoor heat exchangers leads to reduced heat exchange performance and inadequate heating capabilities, as the frost acts as an insulating material, preventing efficient heat absorption from outdoor air.
Innovation Solution
The system incorporates a control mechanism that calculates a maximum heating capability without frosting and utilizes auxiliary heating to complement the radiator's heating capacity, ensuring comfortable interior temperatures while preventing frost formation on the outdoor heat exchanger by adjusting the heating modes based on predicted frost conditions and environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heating mode is executed by starting a vehicular air-conditioning device, then the refrigerant discharged from the compressor radiates heat in the radiator and absorbs heat in the outdoor heat exchanger, but water in outdoor air adheres as frost to the outdoor heat exchanger and grows, causing heat exchange performance to deteriorate
Solution Approach 1:
The control means calculates the maximum heating capability predicted value without frosting QmaxNfst in advance, before frost formation occurs. This predictive calculation allows the system to take preliminary action by adjusting heating control before the harmful frost formation deteriorates heat exchange performance.
Solution Approach 2:
The control means continuously monitors and adjusts the heating operation based on feedback from the calculated maximum heating capability predicted value without frosting QmaxNfst and the required heating capability Qtgt. This feedback mechanism ensures that heating is maintained at optimal levels to prevent frost while meeting heating demands.
2Temperature
If the frost formation to the outdoor heat exchanger occurs in the heating mode, then the frost becomes an insulating material and heat cannot be absorbed from the outdoor air, but the control system must maintain the required heating capability Qtgt
Solution Approach 1:
The control means applies preliminary anti-action by calculating the maximum heating capability predicted value without frosting QmaxNfst and using this information to prevent frost formation before it occurs. By anticipating the frost formation risk and taking preventive heating control measures, the system avoids the insulating effect of frost that would otherwise block heat absorption.
Solution Approach 2:
The control means changes the heating operation parameters based on the calculated maximum heating capability predicted value without frosting QmaxNfst and required heating capability Qtgt. By adjusting heating parameters dynamically, the system maintains efficient heat absorption while preventing frost formation that would act as an insulating barrier.
3Temperature
If auxiliary heating means is used to complement the radiator's heating capacity, then the required heating capability Qtgt can be achieved without frost formation, but the system complexity increases
Solution Approach 1:
The control means serves multiple functions: it calculates the maximum heating capability predicted value without frosting QmaxNfst, compares it with the required heating capability Qtgt, and adjusts heating operation accordingly. This multi-functionality reduces the need for separate dedicated components, managing system complexity while achieving the heating capability.
Solution Approach 2:
The control system performs self-service by autonomously calculating the maximum heating capability predicted value without frosting QmaxNfst and automatically adjusting the heating operation based on this calculation and the required heating capability Qtgt. This self-regulating mechanism eliminates the need for complex external control systems while preventing frost formation.
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 approach effectively prevents frost formation on the outdoor heat exchanger, maintaining efficient heat exchange and achieving the required heating capacity without reducing the vehicle's cruising range or increasing power consumption, thereby ensuring comfortable interior heating.
Implementation Method 1
a radiator which lets the refrigerant radiate heat to heat the air to be supplied from the air flow passage into the vehicle interior
Implementation Method 2
a heat absorber which lets the refrigerant absorb heat to cool the air to be supplied from the air flow passage into the vehicle interior
Implementation Method 3
an outdoor heat exchanger disposed outside the vehicle interior to let the refrigerant radiate or absorb heat
Implementation Method 4
a compressor which compresses a refrigerant
Data Source
AI summary
There is disclosed an air-conditioning device of a so-called heat pump system which acquires comfortable heating of a vehicle interior by preventing or inhibiting frost formation to an outdoor heat exchanger. A controller calculates a maximum heating capability predicted value without frosting QmaxNfst as a target value of a maximum heating capability which can be generated by a radiator 4 in a range in which an outdoor heat exchanger 7 is not frosted, and controls heating by the radiator 4 and heating by a heating medium-air heat exchanger 40 of a heating medium circulating circuit 23 on the basis of the maximum heating capability predicted value without frosting QmaxNfst and a required heating capability Qtgt which is the heating capability required for the radiator 4 to achieve the required heating capability Qtgt without causing frost formation to the outdoor heat exchanger 7.