Patent Application
20150114018
The present disclosure relates to a heat pump system including a viscous heater for supplementing heat during a heat mode of the heat pump system.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Vehicles having internal combustion engines can use excess heat produced from the engine to heat a passenger cabin of the vehicle. Electric vehicles, which may not have an engine, produce little wasted heat, and, therefore, may need another heating system to heat the passenger cabin. For instance, due to their efficiency and ability to reuse components from conventional air-conditioning system, heat pumps have been utilized in electric vehicles to heat and cool the passenger cabin.
However, heat pumps may not provide enough heating performance at very low temperatures. To overcome such heating deficiency, the capacity of a compressor of the heat pump can be increased. Unfortunately, such an increase may require the use of a non-standard compressor. Thus, requiring another model of a compressor which may have a low manufacturing output and therefore, a higher cost in piece price. Furthermore, a large compressor may not be efficient for moderate conditioning, such as mild heating, which is when the heat pump is used most often.
As another alternative, heat generating devices can be provided to supplement heat to the heat pump. For instance, positive temperature coefficient (PTC) heaters can be used with the heat pump. However, the performance and efficiency of the PTC heater reduces as an inlet temperature increases. The low efficiency of the PTC heater can have a negative effect on the driving range of the electric vehicle. Furthermore, PTC heaters are not typically utilized in a vehicle air conditioning system, and therefore, may be expensive to implement.
This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.
The present disclosure provides for an air-conditioning system for a vehicle. The air-conditioning system can include a heat pump system and a viscous heater disposed within the heat pump system. The viscous heater can be configured to supplement the heat pump system during a heat mode of the air-conditioning system.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
With reference to
The heat pump system 4, as shown in
The compressor 8 sucks, compresses, and discharges refrigerant into the GIHP 6. The compressor 8 can include a suction port for drawing vapor refrigerant from the accumulator 16, a gas-injection port for receiving vapor refrigerant from the gas-liquid separator 12 via the viscous heater 18, and a discharge port for discharging compressed refrigerant. The compressor 8 may be an electric compressor that drives a fixed displacement compressor mechanism having a fixed charge capacity by way of an electric motor. Various types of compressors having a fixed displacement compressor mechanism, such as a scroll type compressor and a vane compressor, may be employed. The compressor 8 may also be a variable displacement type compressor.
The compressor 8 is coupled to the internal condenser 10, such that refrigerant flows from the compressor 8 to the internal condenser 10. The internal condenser 10 can be disposed within an air duct housing of the AC system 2 which provides conditioned air to the passenger cabin of the vehicle. The internal condenser 10 heats the air flowing from an evaporator by transferring heat from the refrigerant flowing therein to the air passing through. The air may then enter the passenger cabin of the vehicle via air vents provided within the passenger cabin after being conditioned to a desired temperature by the AC system 2.
Refrigerant from the internal condenser 10 flows to an expansion device 20 which decompresses and expands the refrigerant. From the expansion device 20, the refrigerant flows to the gas-liquid separator 12 which separates the refrigerant into its liquid and vapor forms. The liquid portion of the refrigerant can flow to the external heat exchanger 14 by way of an expansion device 21, which, like the expansion device 20, decompresses and expands the refrigerant. The vapor portion of the refrigerant flows to the compressor 8 by way of the viscous heater 18.
The external heat exchanger 14 may be disposed in a front portion of the vehicle, and exchanges heat between the refrigerant flowing therein and the outside air being blown in by a fan. During the heat mode of the heat pump system 4, the external heat exchanger 14 performs like an evaporator by transferring heat from outside air being blown through to the refrigerant flowing therein, thereby heating the refrigerant.
The refrigerant flows from the external heat exchanger 14 to the accumulator 16 which separates the vapor and liquid forms of the refrigerant. The compressor 8 sucks in vaporous refrigerant from the accumulator 16.
During the heat mode of the AC system 2, the viscous heater 18 heats refrigerant entering the compressor 8 of the GIHP 6. Similar to viscous heaters used in diesel engines, the viscous heater 18 generates heat by shearing viscous fluid provided within a chamber 24 of the viscous heater 18. Specifically, a rotor 26 rotates within the chamber 24 to shear the viscous fluid (
The viscous heater 18 can be a variable capacity heater with an ON/OFF state function for controlling the viscous heater 18. For example, the viscous heater may be placed in an OFF state (turned off) when it is not needed, such as during a cooling mode in which the passenger cabin of the vehicle is being cooled. Conversely, during the heat mode, the viscous heater 18 can be in an ON state (turned on). The viscous heater 18 can be controlled by a control unit (C) 25 of the AC system 2 which also controls the heat pump system 4.
The control unit 25 may include a CPU, a RAM, and a ROM. The control unit 25 receives information from various sensors disposed throughout the AC system 2 and from climate control gauges disposed on an instrument panel of the vehicle which can be operated by a user. Based on such information, the control unit 25 controls various components of the AC system 2 to heat and cool air to the desired temperature.
The GIHP 6 heats the passenger cabin of the vehicle by transferring heat from outside of the vehicle to the passenger cabin. As indicated by the arrows in
The internal condenser 10 warms the air, which is ultimately provided to the passenger cabin, by transferring heat from the refrigerant flowing therein to air passing through. The refrigerant, which may now be a mixture of vapor and liquid, is decompressed by the expansion device 20 before being separated by the gas-liquid separator 12. From the gas-liquid separator 12, liquid refrigerant flows to the expansion device 21 where it can be decompressed before entering the external heat exchanger 14. By performing like an evaporator, the external heat exchanger 14 heats refrigerant flowing therein by transferring heat from outside air blowing through the external heat exchanger 14 to the refrigerant. Refrigerant from the external heat exchanger 14 may be a mixture of vapor and liquid, and is separated by the accumulator 16.
Vaporous refrigerant from the gas-liquid separator 12 is heated by the viscous heater 18 before being injected into the compressor 8. The refrigerant heated by the viscous heater 18 increases the temperature of the refrigerant discharged by the compressor 8 to the internal condenser 10. Thus, the heating performance of the internal condenser and, ultimately the AC system 2, is improved.
In the event that the viscous heater 18 receives liquid refrigerant with the vapor refrigerant from the gas-liquid separator 12, the viscous heater 18 can heat the liquid refrigerant into a vaporous form. Thus, any liquid refrigerant is prevented from entering the compressor 8.
Although the viscous heater 18 is shown in
Although only one viscous heater 18 is shown in
The viscous heater 18 can be powered by an electric motor using various suitable configurations. For instance, as illustrated in
Alternatively, the viscous heater 18 can be integrated with the heat pump system 4 such that the viscous heater 18 is powered by an electric motor already provided in the heat pump system 4. For example, as illustrated in
In another example shown in
In utilizing the GIHP 6 with the viscous heater 18, the heating performance of the AC system 2 of the present disclosure is improved over that of conventional methods. For instance,
With reference to
With reference to
With respect to the GIHP-PTC, the GIHP-VH has similar performance and power consumption as the GIHP-PTC. However, as the air temperature at an inlet of the internal condenser increases, the performance of the GIHP-VH system may increase rapidly over the GIHP-PTC. Specifically, the GIHP-PTC heats the air entering the internal condenser. As an inlet temperature of the internal condenser increases, the performance and efficiency of the PTC heater decreases.
With reference to
In addition to improved performance, the AC system 2 has improved noise-vibration-harshness (NVH) qualities when compared to the GIHP-Baseline and GIHP-PTC. The speed of a compressor is closely related to the NVH qualities of the compressor. In a situation in which the same or substantially the same level of performance is required in each of the system, the GIHP-VH may be the preferred system.
For instance, with reference to
With reference to
In regards to the GIHP-PTC, the GIHP-VH has about the same or similar level of performance as the GIHP-PTC. However, as shown in
The AC system 2 of the present disclosure may include a normal or standard size compressor, thereby employing standard heat pump components readily available. With a standard size compressor, the GIHP-VH has improved performance capabilities over the GIHP-Baseline. The GIHP-VH may also use a smaller compressor than, for example, the GIHP-Baseline. With the smaller compressor, the GIHP-VH may have the same performance as the GIHP-Baseline.
In utilizing the viscous heater 18 as a supplemental heat source, the AC system 2 may be less complex to package into the vehicle than the use of PTC heaters. For instance, PTC heaters are typically installed in the air-duct housing which can be a standard component. Packaging space provided in the air duct housing may be constrained, thereby making it difficult to incorporate additional components like PTC heaters. The viscous heater 18 can be integrated with heat pump components, like the compressor 8, or installed at another position under the hood of the vehicle. Thus, the AC system 2 is able to employ standard heat pump components and achieve better heat performance by employing the viscous heater 18 with the heat pump system 4.
In the first embodiment of the present disclosure, the heat pump system 4 of the AC system 2 is provided as the GIHP 6. The GIHP 6 typically performs better than other heat pumps; however, the GIHP 6 can be more complex, costly, and can be difficult to package. As an alternative to the GIHP 6, the heat pump system 4 can be a simple heat pump 40, as shown in
Without the gas-liquid separator 12, the compressor 8 of the simple heat pump 40 draws vapor refrigerant from the accumulator 16 via the suction port and discharges compressed refrigerant to the internal condenser 10 via the discharge port. Accordingly, the compressor 8 does not receive additional vaporous refrigerant which is provided in the GIHP 6 by way of the gas-liquid separator 12. Instead, refrigerant from the internal condenser 10, which may be in both liquid and vapor forms, flows to the expansion device 21 and then to the external heat exchanger 14.
Similar to the first embodiment, the AC system 2 of the second embodiment includes the viscous heater 18 which can be arranged between compressor 8 and the internal condenser 10. According to such configuration, the simple heat pump 40 heats the passenger cabin of the vehicle by transferring heat from outside air to the passenger cabin. Specifically, as indicated by the arrows in
By arranging the viscous heater 18 between the compressor 8 and the internal condenser 10, the viscous heater 18 heats the refrigerant from the compressor 8 before providing it to the internal condenser 10, thereby increasing the heating performance of the internal condenser 10 and, ultimately, the AC system 2. Therefore, the simple heat pump 40 having the viscous heater 18 improves the performance of the AC system 2 by providing additional heat during the heat mode.
The AC system 2 of the first embodiment, which includes the GIHP 6 and the viscous heater 18, may achieve a higher performance than the AC system 2 of the second embodiment, which includes the simple heat pump 40 and the viscous heater 18. Based on the configuration of the AC system 2 of the first embodiment, the GIHP 6 has a gas injection flow path from the gas-liquid separator 12 to the compressor 8, which, as described above, is not included in the simple heat pump 40. The gas injection flow path increases performance of the heat pump system 4 by adding high pressure, high enthalpy refrigerant to the compressor 8, thereby increasing the pressure and enthalpy of the refrigerant discharged by the compressor 8. By heating vaporous refrigerant from the gas-liquid separator 12, the enthalpy of the vaporous refrigerant leaving the viscous heater 18 increases the effect the vaporous refrigerant has on the compressor 8. Accordingly, the AC system 2 of the first embodiment, which has the GIHP 6 with the viscous heater 18, may perform better than the AC system 2 of the second embodiment having the simple heat pump 40 with the viscous heater 18.
Although the AC system 2 of the first embodiment may have a higher performance than the second embodiment, the simple heat pump 40 with the viscous heater 18 can be less complex and costly than the GIHP 6 with the viscous heater 18. In addition, the viscous heater 18 can provide the same or substantially the same level of supplemental heat performance for the simple heat pump 40, as in the GIHP 6, when it is arranged at the same or similar position along the heat pump system 4. For instance, if the viscous heater 18 is arranged between the compressor 8 and the internal condenser 10 for both the GIHP 6 and the simple heat pump 40, the viscous heater 18 would have the same or substantially the same supplemental effect on the heat pump system 4. Therefore, by employing the simple heat pump 40 with the viscous heater 18, the AC system 2 of the second embodiment provides improved heating performance during the heat mode with less complexity and cost.
Furthermore, the AC system 2 of the second embodiment may also employ standard heat pump components which are readily available, along with the viscous heater 18, which can be easily integrated with the simple heat pump 40.
Similar to the first embodiment, one or more viscous heater 18 can be disposed at various suitable positions within the simple heat pump 40 to heat the refrigerant. For example, as shown in
Certain vehicles, such as the PHEV, may use heat from an engine or a heat pump to heat the vehicle. Such vehicles may utilize the heat pump to heat coolant. The coolant can then be used to heat the vehicle by way of a coolant loop. During cold temperatures, another heat source can be used to supplement the heating performance of the heat pump. For instance, in a third embodiment of the present disclosure, as shown in
The heater core 54 heats the passenger cabin of the vehicle by transferring heat from hot coolant flowing therein to air passing though the heater core 54. The coolant, which may now be cold, flows to the viscous heater 18 by way of the pump 56. The viscous heater 18 warms the coolant before discharging it to the water-to-refrigerant heat exchanger 50. The water-to-refrigerant heat exchanger 50 further warms the coolant flowing therein with the refrigerant from the heat pump system 4. Specifically, the water-to-refrigerant heat exchanger 50 transfers heat from the refrigerant to the coolant which then flows to the heater core 54. The refrigerant leaving the water-to-refrigerant heat exchanger 50 is heated by the heat pump system 4.
Although the viscous heater 18 is provided within the coolant loop 52 in
By having the viscous heater 18 disposed before the water-to-refrigerant heat exchanger 50, the viscous heater 18 preheats the coolant going into the water-to-refrigerant heat exchanger 50. Accordingly, the refrigerant leaving the water-to-refrigerant heat exchanger 50 may have a higher temperature than the refrigerant leaving the water-to-refrigerant heat exchanger 50 when the viscous heater 18 is not provided to preheat the coolant. As a result, the external heat exchanger 14, which can limit the performance of the AC system 2, receives warmer refrigerant at a higher flow rate, thereby increasing the performance of the heat pump system 4.
Furthermore, the third embodiment may provide for a more flexible design than the first and second embodiments. For instance, if conventional hybrid and electric vehicles have the same heat pump system 4, the heat pump system 4 can still be supplemented by disposing the viscous heater 18 along the coolant loop 52 instead of the heat pump system 4.
Although the use of the viscous heater 18 with the heat pump system 4 is described in relation to the AC system 2 of the vehicle, it should be understood that the viscous heater 18 and the heat pump system 4 can be used in other thermal control operations. For example, the viscous heater 18 can be used with the heat pump system 4 and/or coolant loop 52 to control the temperature of a battery pack used in hybrid vehicles and electric vehicles.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
