CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0123945 filed in the Korean Intellectual Property Office on Sep. 24, 2020, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Field

The present disclosure relates to a heat pump system for a vehicle. More particularly, the present disclosure relates to a heat pump system for a vehicle which adjusts a temperature of a battery module by using one chiller that performs heat exchange between a refrigerant and a coolant and improves heating performance by applying a gas injection device.

(b) Description of the Related Art

In general, an air conditioner for a vehicle includes an air conditioning system for circulating a coolant in order to heat or cool an inside of the vehicle.

Such an air conditioner maintains a comfortable indoor environment by maintaining an interior temperature of the vehicle at an appropriate level regardless of an external temperature change, so that the interior of the vehicle is warmed or cooled through heat exchange by a condenser and an evaporator during a process in which a refrigerant discharged by driving of a compressor circulates back to the compressor after passing through a condenser, a receiver dryer, an expansion valve, and an evaporator.

That is, the air conditioner system condenses a gaseous coolant of a high temperature and a high pressure compressed by the compressor in a cooling mode in the summer to reduce a temperature and humidity of the interior of the vehicle through evaporation in the evaporator through the receiver dryer and the expansion valve.

Meanwhile, in recent years, as interest in energy efficiency and environmental pollution has been increasing, there has been a demand for the development of environmentally friendly vehicles configured for substantially replacing internal combustion engine vehicles. The environmentally friendly vehicles are usually fuel cell or electric vehicles driven by electricity or a hybrid vehicle driven by an engine and a battery.

Among the environmentally friendly vehicles, the electric vehicle or the hybrid vehicle does not use a separate heater, unlike an air conditioner of a general vehicle, and the air conditioner applied to the environmentally friendly vehicle is generally referred to as a heat pump system.

On the other hand, in the case of the electric vehicle, chemical reaction energy of oxygen and hydrogen is converted into electrical energy to generate driving force. In the present process, since thermal energy is generated by the chemical reaction in the fuel cell, effectively removing the generated heat is essential in securing performance of the fuel cell.

Furthermore, even in the hybrid vehicle, a motor is driven by use of the electricity supplied from the fuel cell or an electric battery together with an engine that operates by general fuel to generate the driving force, and as a result, the performance of the motor may be secured only by effectively removing the heat generated from the fuel cell or the battery and the motor.

As a result, in the hybrid vehicle or the electric vehicle generally, a battery cooling system needs to be separately formed with a separate sealing circuit together with a cooler and the heat pump system to prevent the heat generation in the motor and electrical components, and the battery including the fuel cell.

Accordingly, the size and weight of a cooling module disposed in the front of the vehicle increase and a layout of connection pipes that supply the refrigerant and the coolant to the heat pump system, the cooler, and the battery cooling system is complicated in an engine compartment.

Furthermore, the battery cooling system which heats or cools the battery according to a status of the vehicle for the battery to show optimal performance is separately provided, and as a result, multiple valves for connection with the respective connection pipes are adopted and noise and vibration due to frequent opening and closing operations of the valves are transferred to the internal of the vehicle to degrade ride comfort.

In addition, when heating the interior of the vehicle, the heating performance decreases due to a lack of a heat source, the amount of electricity consumption increases due to the use of an electric heater, and the power consumption of the compressor increases.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY

The present disclosure has been made in an effort to provide a heat pump system for a vehicle that may simplify a system by controlling a temperature of a battery module by using one chiller in which a refrigerant and a coolant are heat-exchanged.

In addition, the present disclosure has been made in an effort to provide a heat pump system for a vehicle that may maximize heating performance by applying a gas injection device that selectively operates in a heating or dehumidifying mode of a vehicle to increase a flow rate of a refrigerant.

An embodiment of the present disclosure provides a heat pump system for a vehicle, including an air conditioner circulating a refrigerant through a refrigerant line, a coolant circulation apparatus circulating a coolant through a coolant line, a chiller that is connected to the coolant circulation apparatus through the coolant line, is connected to the refrigerant line through a refrigerant connection line, and heat-exchanges a selectively introduced coolant with a refrigerant supplied from the air conditioner to control a temperature of a coolant, and a gas injection device provided in the air conditioner and increasing a flow rate of the refrigerant circulating in the refrigerant line by bypassing some of a refrigerant passing through an internal condenser to a compressor, wherein a heat-exchanger provided in the air conditioner may be connected to the coolant circulation apparatus through the coolant line so that the coolant is supplied from the coolant circulation apparatus.

The air conditioner may include an HVAC module including an evaporator connected thereto through the refrigerant line, and an opening and closing door that controls to selectively flow an external air passing through the evaporator into the internal condenser according to cooling, heating, and dehumidifying modes of the vehicle, the heat-exchanger that heat-exchanges a refrigerant supplied through the refrigerant line with a coolant supplied from the coolant circulation apparatus, a compressor connected between the evaporator and the heat-exchanger through the refrigerant line, a sub-condenser provided in the refrigerant line the heat-exchanger and the evaporator, a first expansion valve provided in the refrigerant line connecting the sub-condenser and the evaporator, a second expansion valve provided in the refrigerant connection line; an accumulator provided in the refrigerant line between the evaporator and the compressor, a branch line having a first end connected to the refrigerant line between the heat-exchanger and the sub-condenser through a refrigerant valve and a second end connected to the accumulator, and a dehumidification line having a first end connected to the refrigerant line between the internal condenser and the heat-exchanger and a second end connected to the refrigerant line between the evaporator and the first expansion valve, and having a check valve.

A first end of the refrigerant connection line may be connected to the refrigerant line between the sub-condenser and the first expansion valve, and a second end of the refrigerant connection line may be connected to the refrigerant line between the accumulator and the evaporator.

The second expansion valve may selectively expand the refrigerant that has passed through the sub-condenser according to a mode of the vehicle to introduce the refrigerant into the refrigerant connection line.

The gas injection device may include a gas-liquid separator provided in the refrigerant line between the internal condenser and the heat-exchanger, and separating and selectively discharging a gaseous refrigerant and a liquid refrigerant among the refrigerant that have passed through the internal condenser, a supply line connecting the gas-liquid separator and the compressor, and selectively supplying the gaseous refrigerant from the gas-liquid separator to the compressor, a control valve provided in the supply line, a third expansion valve provided in the refrigerant line between the internal condenser and the gas-liquid separator, and a fourth expansion valve provided in the refrigerant line between the gas-liquid separator and the heat-exchanger.

When the gas injection device is operated in a heating mode of the vehicle, the third expansion valve may expand the refrigerant supplied from the internal condenser to supply the refrigerant to the gas-liquid separator; and the fourth expansion valve may expand the refrigerant supplied from the gas-liquid separator to supply it to the heat-exchanger.

When the gas injection device is not operated in a heating mode of the vehicle, the third expansion valve may pass the refrigerant supplied from the internal condenser, and the fourth expansion valve may expand the refrigerant that has passed through the gas-liquid separator to supply the refrigerant to the heat-exchanger.

When the gas injection device is not operated in a dehumidifying mode of the vehicle, the third expansion valve may pass the refrigerant supplied from the internal condenser, and the fourth expansion valve may expand the refrigerant that has passed through the gas-liquid separator to supply the refrigerant to the heat-exchanger.

When the gas injection device is operated in a dehumidifying mode of the vehicle, the third expansion valve may expand the refrigerant supplied from the internal condenser to supply the refrigerant to the gas-liquid separator, and the fourth expansion valve may expand the refrigerant supplied from the gas-liquid separator to supply the refrigerant to the heat-exchanger.

In a cooling mode of the vehicle, the third and fourth expansion valves may not expand the refrigerant supplied from the internal condenser, but may flow the refrigerant through the refrigerant line.

The control valve, when the gas injection device is operated, may operate so that the supply line may be opened.

The second, third, and fourth expansion valves may be electronic expansion valves that selectively expand the refrigerant while controlling flowing of the refrigerant.

The heat-exchanger may additionally condense or evaporate the refrigerant discharged from the gas-liquid separator through heat-exchange with the coolant, according to a selective operation of the fourth expansion valve.

When a battery module is cooled in a cooling mode of the vehicle, the coolant circulation apparatus may supply the coolant to the heat-exchanger and the chiller through the coolant line connected to the heat-exchanger and the chiller, in the air conditioner, the refrigerant connection line may be opened by the second expansion valve, the refrigerant may be circulated along the refrigerant line and the refrigerant connection line, the first and second expansion valves may expand the refrigerant so that an expanded refrigerant is supplied to the evaporator and the chiller, respectively, the branch line may be closed by the refrigerant valve, the refrigerant line connecting the heat-exchanger and the sub-condenser may be opened by the refrigerant valve, the heat-exchanger may condense the refrigerant through heat-exchange with the coolant, and the sub-condenser may further condense the refrigerant through heat-exchange with external air.

In a heating mode of the vehicle, the coolant circulation apparatus may supply the coolant to the heat-exchanger through the coolant line connected to the heat-exchanger, in the air conditioner, the refrigerant line connecting the sub-condenser and the evaporator may be closed by the first expansion valve, the refrigerant connection line may be closed by of the second expansion valve, the fourth expansion valve may expand the refrigerant, the branch line may be opened by the refrigerant valve, the refrigerant line connecting the heat-exchanger and the sub-condenser may be closed by the refrigerant valve, the heat-exchanger may evaporate the refrigerant through heat-exchange with the coolant, and the gas injection device may be selectively operated.

In a dehumidifying mode of the vehicle, the coolant circulation apparatus may supply the coolant to the heat-exchanger through the coolant line connected to the heat-exchanger, in the air conditioner, the refrigerant line connecting the sub-condenser and the evaporator may be closed by the first expansion valve, the refrigerant connection line may be closed by the second expansion valve, the branch line is opened by the refrigerant valve, the refrigerant line connecting the heat-exchanger and the sub-condenser may be closed by the refrigerant valve, the heat-exchanger may evaporate the refrigerant through heat-exchange with the coolant, the fourth expansion valve may expand the refrigerant, the dehumidification line may be opened by the check valve so that the refrigerant expanded by the fourth expansion is supplied to the evaporator, and the gas injection device may be selectively operated.

The gas injection device may include a plate-shaped heat-exchanger provided in the refrigerant line between the heat-exchanger and the sub-condenser, a supply line that includes a first end connected to the refrigerant line between the heat-exchanger and the plate-shaped heat-exchanger and a second end connected to the compressor through the plate-shaped heat-exchanger, a third expansion valve provided in the supply line at a front end of the plate-shaped heat-exchanger, and a fourth expansion valve provided in the refrigerant line between the plate-shaped heat-exchanger and the sub-condenser.

The heat-exchanger may be a water-cooled heat-exchanger, and the sub-condenser may be an air-cooled heat-exchanger.

The gas injection device may selectively operate in a heating or dehumidifying mode of the vehicle.

As described above, according to the heat pump system for the vehicle according to the embodiment of the present disclosure, simplification of the system may be realized, by using one chiller in which a refrigerant and a coolant are heat-exchanged to control a temperature of a battery module according to a vehicle mode.

In addition, according to the embodiment of the present disclosure, by efficiently controlling a temperature of a battery module, it is possible to operate the battery module at optimal performance, and a total mileage of the vehicle may be increased through efficient management of the battery module.

In addition, according to the embodiment of the present disclosure, it is possible to maximize heating performance by selectively increasing a flow rate of refrigerant in a heating or dehumidifying mode of a vehicle by applying a gas injection device.

Furthermore, according to the embodiment of the present disclosure, it is possible to reduce manufacturing cost and weight through simplification of an entire system, and to improve space utilization.

