Vehicle air conditioning system

Abstract

To provide a vehicular air conditioner that can determine a state of a refrigerant more adequately, by distinguishing between a warm-up state and a cold state of an engine and managing the state of the refrigerant.SOLUTION: A vehicular air conditioner 100 comprises: a compressor 102 that compresses a refrigerant; a cooling water temperature sensor 124 that measures a temperature of an engine 108; an outside air temperature sensor 126 that measures an outside air temperature; a refrigerant state determining part 132 that determines whether a refrigerant is insufficient or excessively filled; and a compressor control part 134 that when the refrigerant state determining part determines that the refrigerant is insufficient or excessively filled, stops the compressor. The refrigerant state determining part compares a temperature of the engine measured by the cooling water temperature sensor with the outside air temperature measured by the outside air temperature sensor to determine whether the engine is in a warm-up state or in a cold state; when refrigerant pressure of the refrigerant is below a first threshold, determines that the refrigerant is insufficient, and when the refrigerant pressure is above a second threshold, determines that the refrigerant is excessively filled; and changes the first threshold and the second threshold, depending on whether the engine is in the warm-up state or in the cold state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an air conditioner for a vehicle. [Background technology]

[0002] Vehicles such as automobiles are equipped with vehicle air conditioners. Vehicle air conditioners include an air conditioning unit (also called HVAC) that is located in the instrument panel or elsewhere, and maintain a comfortable interior of the vehicle by blowing conditioned air from the air conditioning unit.

[0003] If a vehicle air conditioner continues to operate with a shortage of refrigerant, it may cause problems such as overheating or an abnormal rise in the temperature of the compressor that compresses the refrigerant, which can damage or lock rubber parts. For this reason, it is necessary for the vehicle air conditioner to determine whether there is a shortage of refrigerant.

[0004] Patent Document 1 describes a refrigeration device including a bypass circuit for bypassing a refrigerant, multiple refrigerant flow paths, a first refrigerant flow rate calculation unit, a second refrigerant flow rate calculation unit, and a judgment unit. The first refrigerant flow rate calculation unit calculates the refrigerant flow rate flowing through the bypass circuit as a first refrigerant flow rate based on refrigeration cycle theory. The second refrigerant flow rate calculation unit calculates the refrigerant flow rate flowing through the bypass circuit as a second refrigerant flow rate based on fluid theory. The judgment unit judges whether there is a refrigerant leak or a shortage of the charged refrigerant amount based on a comparison result between the first refrigerant flow rate and the second refrigerant flow rate.

[0005] In the refrigeration device of Patent Document 1, the refrigerant flow rate flowing through the bypass circuit is calculated as a first refrigerant flow rate based on refrigeration cycle theory, while being calculated as a second refrigerant flow rate based on fluid theory, and the presence or absence of refrigerant leakage or insufficient charged refrigerant is determined by comparing the first refrigerant flow rate with the second refrigerant flow rate. As a result, it is possible to determine the presence or absence of refrigerant leakage or insufficient charged refrigerant without the need to calculate an optimal refrigerant amount in advance by testing or simulation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-191503 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology described in Patent Document 1 requires multiple refrigerant flow paths, and multiple circuits and measuring devices are required, making the device complicated. In addition, even if the state of the refrigerant, i.e., whether there is a shortage or overfill of the refrigerant, is determined based on the refrigerant pressure of the refrigerant, the refrigerant pressure varies depending on conditions other than the refrigerant flow rate. For this reason, it is difficult to accurately determine the state of the refrigerant by simply comparing the refrigerant flow rates, as in Patent Document 1.

[0008] In view of these problems, the present invention aims to provide an air conditioning system for a vehicle that can more accurately determine the state of the refrigerant by distinguishing between a warm-up state and a cold-up state of the engine and managing the state of the refrigerant. [Means for solving the problem]

[0009] In order to solve the above problems, a representative configuration of a vehicle air conditioner according to the present invention is a vehicle air conditioner that conditions the air inside a vehicle cabin by circulating a refrigerant, and includes a compressor that compresses the refrigerant, a first sensor that measures the engine temperature, a second sensor that measures the outside air temperature, a refrigerant state determination unit that determines whether a refrigerant shortage or overfill has occurred, and a compressor control unit that stops the compressor when the refrigerant state determination unit determines that there is a refrigerant shortage or overfill, and is characterized in that the refrigerant state determination unit compares the engine temperature measured by the first sensor with the outside air temperature measured by the second sensor and determines whether the engine is in a warm-up state or a cold-up state depending on the comparison result, determines that there is a refrigerant shortage when the refrigerant pressure of the refrigerant is less than a predetermined first threshold, and determines that there is an overfill of the refrigerant when the refrigerant pressure is equal to or greater than a predetermined second threshold, and changes the first threshold and the second threshold depending on whether the engine is in a warm-up state or a cold-up state. Effect of the Invention

[0010] According to the present invention, a vehicle air conditioner can be provided that can more accurately determine the state of the refrigerant by distinguishing between a warm-up state and a cold-up state of the engine and managing the state of the refrigerant. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing a configuration of a vehicle air conditioner according to an embodiment of the present invention; [Diagram 2] 2 is a flowchart showing a process of the vehicle air conditioner of FIG. 1. [Diagram 3] 2 is a diagram showing a reference threshold value used in the refrigerant state determination unit in FIG. 1. [Figure 4] FIG. 4 is a diagram showing correction values ​​for correcting the reference threshold values ​​in FIG. 3. [Diagram 5] 1. FIG. 4 is a diagram showing another reference threshold map and a correction value map used in the refrigerant state determination unit in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A typical configuration of a vehicle air conditioner according to one embodiment of the present invention is a vehicle air conditioner that conditions the air inside a vehicle cabin by circulating a refrigerant, and includes a compressor that compresses the refrigerant, a first sensor that measures the engine temperature, a second sensor that measures the outside air temperature, a refrigerant state determination unit that determines whether a refrigerant shortage or overfill has occurred, and a compressor control unit that stops the compressor when the refrigerant state determination unit determines a refrigerant shortage or overfill. The refrigerant state determination unit compares the engine temperature measured by the first sensor with the outside air temperature measured by the second sensor and determines whether the engine is in a warm-up state or a cold-up state depending on the comparison result, determines a refrigerant shortage when the refrigerant pressure of the refrigerant is less than a predetermined first threshold, and determines a refrigerant overfill when the refrigerant pressure is equal to or greater than a predetermined second threshold, and changes the first threshold and the second threshold depending on whether the engine is in a warm-up state or a cold-up state.

[0013] In the above configuration, the engine temperature (for example, the temperature of the engine coolant or oil) is compared with the outside air temperature to determine whether the engine is in a warm or cold state. The engine is then distinguished between a warm and cold state and the threshold value for determining whether the refrigerant is insufficient or overfilled is changed.

[0014] Therefore, according to the above configuration, the state of the refrigerant can be more accurately determined by distinguishing between a warm-up state and a cold-up state of the engine and managing the state of the refrigerant. Also, when the refrigerant is insufficient or overfilled, the compressor is stopped, thereby preventing malfunctions in the vehicle air conditioning system.

[0015] The above-mentioned vehicle air conditioning system further has a reference threshold map indicating a reference threshold determined by the outside air temperature, and a correction value map indicating a correction value for correcting the reference threshold, and the refrigerant state determination unit determines the first threshold and the second threshold based on the reference threshold map when the engine is in a cold state, and determines the first threshold and the second threshold based on the reference threshold map and the correction value map when the engine is in a warm state.

[0016] In the above configuration, a reference threshold map indicating the reference threshold value and a correction value map indicating the correction value for correcting the reference threshold value are prepared in advance, and each map can be read out to select a threshold value by distinguishing between the warm-up state and the cold-up state of the engine.

[0017] That is, when the engine is in a cold state, the state of the refrigerant can be determined using the first and second thresholds as reference thresholds indicated in the reference threshold map. Also, when the engine is in a warm-up state, the state of the refrigerant can be determined using each of the corrected thresholds obtained by correcting the first and second thresholds using the correction values ​​indicated in the correction value map. In this way, with a simple configuration of reading out a map prepared in advance, it is possible to distinguish between a warm-up state and a cold-up state of the engine and accurately determine the state of the refrigerant in a short time.

[0018] The correction value of the above correction value map is determined according to the temperature difference between the engine temperature and the outside air temperature, and the refrigerant state determination unit determines that the engine is in a cold state when the engine temperature is the same as the outside air temperature, and determines that the engine is in a warm state when the engine temperature is greater than the outside air temperature.

[0019] By comparing the engine temperature with the outside air temperature in this way, it is possible to determine whether the engine is in a cold or warm state. The first and second thresholds are corrected by correcting the reference thresholds using a correction value in a correction value map that is determined according to the temperature difference between the engine temperature and the outside air temperature, and are values ​​that take into account temperature changes due to engine operation. Therefore, when the engine is in a warm state, the state of the refrigerant can be determined more accurately by using the correction thresholds. EXAMPLES

[0020] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0021] 1 is a diagram showing the configuration of a vehicle air conditioner 100 according to an embodiment of the present invention. The vehicle air conditioner 100 is a device that conditions the air inside a vehicle cabin by circulating a refrigerant, and includes a compressor 102 that compresses the refrigerant gas, an air conditioning unit (HVAC) 104, and a condenser 106.

[0022] In the vehicle air conditioner 100, the compressor 102 compresses the refrigerant gas to a high temperature and high pressure state. The compressor 102 is driven by the engine 108 via a belt 110. The gaseous refrigerant that has become high temperature and high pressure in the compressor 102 is sent to the condenser 106 via the refrigerant pipe 112.

[0023] A condenser fan 114 that takes in outside air into the engine room is disposed on the vehicle rear side of the condenser 106. The condenser 106 forcibly cools and liquefies the high-temperature, high-pressure gaseous refrigerant by the outside air taken in by the condenser fan 114. The refrigerant liquefied in the condenser 106 is reduced in pressure through an expansion valve 118 via the refrigerant piping 116, and is further sent to an evaporator 120 in the air conditioning unit 104.

[0024] The evaporator 120 exchanges heat between the refrigerant decompressed by the expansion valve 118 and the air in the vehicle cabin, thereby cooling the refrigerant. Then, cool air is generated by passing wind generated by a blower fan (not shown) in the air conditioning unit 104 through the cooled evaporator 120. The refrigerant sent to the evaporator 120 passes through a refrigerant pipe 122, passes through the compressor 102, and further passes through the refrigerant pipe 112 to return to the condenser 106.

[0025] The vehicle air conditioner 100 further includes a coolant temperature sensor 124 as a first sensor that measures the temperature of the engine 108, a second sensor (outside air temperature sensor 126) that measures the outside air temperature, a refrigerant pressure sensor 128, and an electronic control unit (ECU) 130. The first sensor is not limited to the coolant temperature sensor 124 that measures the coolant of the engine 108, but may be a sensor that measures the temperature of the engine oil. The refrigerant pressure sensor 128 is disposed in the refrigerant pipe 116, and measures the refrigerant pressure of the refrigerant.

[0026] The ECU 130 includes a refrigerant state determination unit 132, a compressor control unit 134, and a memory 136. The refrigerant state determination unit 132 determines the state of the refrigerant, i.e., whether or not there is a shortage or overfill of the refrigerant. The compressor control unit 134 stops the compressor 102 when the refrigerant state determination unit 132 determines that there is a shortage or overfill of the refrigerant.

[0027] The memory 136 stores a reference threshold map 138 (see FIG. 3(a)) and a correction value map 140 (see FIG. 4(a)) used by the refrigerant state determination unit 132 to determine the state of the refrigerant, as well as another reference threshold map 142 and correction value map 144 shown in FIG. 5.

[0028] The following is a list of vehicle airbags. Arrangement The operation of the vehicle air conditioning device 100 will be described. outfit 1 is a flowchart showing the process of the apparatus 100.

[0029] First, the refrigerant state determination unit 132 of the ECU 130 determines whether the engine 108 is in a warm-up state (step S100). In step S100, when the engine 108 coolant temperature measured by the coolant temperature sensor 124 is higher than the outside air temperature measured by the outside air temperature sensor 126, it is determined that the engine 108 is in a warm-up state. On the other hand, when the engine 108 coolant temperature and the outside air temperature are the same, the refrigerant state determination unit 132 determines that the engine 108 is in a cold state.

[0030] Fig. 3 is a diagram showing a reference threshold value P used in refrigerant state determination unit 132 of Fig. 1. Fig. 4 is a diagram showing a correction value A for correcting reference threshold value P of Fig. 3. Fig. 5 is a diagram showing another reference threshold value map 142 and correction value map 144 used in refrigerant state determination unit 132 of Fig. 1.

[0031] If the engine 108 is in a warm-up state in step S100 of Fig. 2 (Yes), the refrigerant state determination unit 132 reads out the correction value map 140 shown in Fig. 4(a) and another correction value map 144 shown in Fig. 5(b) from the memory 136 (step S102). Next, the refrigerant state determination unit 132 reads out the reference threshold map 138 shown in Fig. 3(a) and another reference threshold map 144 shown in Fig. 5(a) from the memory 136. threshold The value map 142 is read (step S104).

[0032] The reference threshold value P of the reference threshold value map 138 is determined by the outside air temperature as shown in the graph of Fig. 3(b). Also, the correction value A of the correction value map 140 is determined according to the temperature difference between the coolant temperature of the engine 108 and the outside air temperature as shown in the graph of Fig. 4(b).

[0033] Then, the refrigerant state determination unit 132 determines a first threshold value for determining a refrigerant shortage based on the read reference threshold value map 138 and correction value map 140. The first threshold value here is set to a corrected threshold value "P+A" obtained by correcting the reference threshold value P by the correction value A. In other words, when the engine 108 is in a warm-up state, the first threshold value is "P+A".

[0034] On the other hand, in step S100, if the engine 108 coolant temperature and the outside air temperature are the same and the engine 108 is in a cold state (No), the refrigerant state determination unit 132 does not read out the correction value map 140, and determines the first threshold value based only on the reference threshold value map 138. In other words, when the engine 108 is in a cold state, the reference threshold value P is not corrected, and the first threshold value becomes "P." In this way, the refrigerant state determination unit 132 changes the first threshold value depending on whether the engine 108 is in a warm state or a cold state.

[0035] Next, the refrigerant state determination unit 132 determines whether the refrigerant pressure of the refrigerant measured by the refrigerant pressure sensor 128 is less than a first threshold value (step S106). If the refrigerant pressure is less than the first threshold value in step S106 (Yes), the refrigerant state determination unit 132 detects a shortage (or leakage) of refrigerant (step S108). Next, when the refrigerant state determination unit 132 determines that there is a shortage of refrigerant, the compressor control unit 134 of the ECU 130 stops the compressor 102 (step S110).

[0036] On the other hand, in step S106, if the refrigerant pressure is equal to or greater than the first threshold (No), the refrigerant state determination unit 132 determines whether the refrigerant pressure is equal to or greater than a second threshold (step S112). The second threshold is a threshold for determining whether the refrigerant is overfilled. If the engine 108 is in a warm-up state, the refrigerant state determination unit 132 determines the second threshold for determining whether the refrigerant is overfilled, based on the reference threshold map 142 and the correction value map 144 shown in FIG. 5 that are read from the memory 136 in steps S102 and S104.

[0037] The reference threshold value P' in the reference threshold value map 142 is determined by the outside air temperature as shown in Fig. 5(a). Moreover, the correction value A' in the correction value map 144 is determined according to the temperature difference between the coolant temperature of the engine 108 and the outside air temperature as shown in Fig. 5(b). The second threshold value here is set to a corrected threshold value "P'+A'" obtained by correcting the reference threshold value P' by the correction value A'. In other words, when the engine 108 is in a warm-up state, the second threshold value is "P'+A'".

[0038] On the other hand, when engine 108 is in a cold state, refrigerant state determination unit 132 does not read correction value map 144, and determines the second threshold value based only on reference threshold value map 142. In other words, when engine 108 is in a cold state, reference threshold value P' is not corrected, and the second threshold value becomes "P'." In this way, refrigerant state determination unit 132 changes the second threshold value depending on whether engine 108 is in a warm state or a cold state.

[0039] If the refrigerant pressure is equal to or greater than the second threshold in step S112 (Yes), the refrigerant state determination unit 132 detects refrigerant overfill (step S114). Next, when the refrigerant state determination unit 132 determines that the refrigerant is overfilled, the compressor control unit 134 stops the compressor 102 (step S110). On the other hand, if the refrigerant pressure is less than the second threshold in step S112 (No), the compressor 102 is not stopped and the process ends.

[0040] In this way, the vehicle air conditioning device 100 judges whether the engine 108 is in a warm or cold state by comparing the temperature of the engine 108 (for example, the temperature of the coolant or oil of the engine 108) with the outside air temperature. The warm and cold states of the engine 108 are distinguished from each other, and the threshold value for judging whether the refrigerant state is insufficient or overfilled is changed, so that the refrigerant state can be judged more accurately.

[0041] In addition, in the vehicle air conditioning system 100, when it is determined that there is a refrigerant shortage or overfill, the compressor 102 is stopped, thereby preventing, for example, an abnormal rise in the temperature of the compressor 102, which can cause problems such as damage to rubber parts or locking.

[0042] Furthermore, in the vehicle air conditioning system 100, reference threshold maps 138, 142 indicating the reference threshold values ​​P, P' and correction value maps 140, 144 indicating correction values ​​A, A' for correcting the reference threshold values ​​P, P' are stored in advance in the memory 136, and it is possible to read out each map and select a threshold value by distinguishing between the warm-up state and the cold-up state of the engine 108.

[0043] That is, when the engine 108 is in a cold state, the state of the refrigerant can be determined using the first and second thresholds as the reference thresholds P and P' indicated in the reference threshold maps 138 and 142. Also, when the engine 108 is in a warm state, the state of the refrigerant can be determined using the corrected thresholds "P+A" and "P'+A'" obtained by correcting the first and second thresholds using the correction values ​​A and A' indicated in the correction value maps 140 and 144.

[0044] In this manner, the vehicle air conditioner 100 can accurately determine the state of the refrigerant in a short time by simply reading out each map previously stored in the memory 136 and distinguishing between the warm and cold states of the engine 108.

[0045] Furthermore, when the engine 108 is in a warm-up state, the corrected thresholds "P+A" and "P'+A'" obtained by correcting the first and second thresholds are obtained by correcting the reference thresholds P, P' using the correction values ​​A, A' in the correction value maps 140, 144 that are determined according to the temperature difference between the temperature of the engine 108 and the outside air temperature, and are values ​​that take into account changes in temperature due to the operation of the engine 108. Therefore, when the engine 108 is in a warm-up state, the vehicle air conditioning device 100 can more accurately determine the state of the refrigerant by using the correction thresholds.

[0046] The values ​​in each map are merely examples, and in reality, they need to be adapted depending on the air conditioning system and vehicle. However, as shown in each map, the higher the outside air temperature, the higher the reference threshold value becomes, and the larger the temperature difference between the engine 108 coolant temperature and the outside air temperature (the larger the thermal effect of the engine 108), the larger the correction value of the reference threshold value can be set.

[0047] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0048] The present invention can be used in vehicle air conditioners. [Explanation of symbols]

[0049] 100...vehicle air conditioning device, 102...compressor, 104...air conditioning unit, 106...condenser, 108...engine, 110...belt, 112, 116, 122...refrigerant piping, 114...condenser fan, 118...expansion valve, 120...evaporator, 124...coolant temperature sensor, 126...outside air temperature sensor, 128...refrigerant pressure sensor, 130...electronic control unit, 132...refrigerant state determination unit, 134...compressor control unit, 136...memory, 138, 142...reference threshold map, 140, 144...correction value map

Claims

1. An air conditioning device for a vehicle that conditions the air inside a vehicle cabin by circulating a refrigerant, a compressor for compressing the refrigerant; A first sensor for measuring a temperature of the engine; a second sensor for measuring an outside air temperature; a refrigerant state determination unit that determines whether the refrigerant is insufficient or overfilled; a compressor control unit that stops the compressor when the refrigerant state determination unit determines that the refrigerant is insufficient or overfilled, The refrigerant state determination unit is comparing the engine temperature measured by the first sensor with the outside air temperature measured by the second sensor, and determining whether the engine is in a warm-up state or a cold-up state according to a result of the comparison; When the refrigerant pressure of the refrigerant is less than a predetermined first threshold, it is determined that the refrigerant is insufficient, and when the refrigerant pressure is equal to or greater than a predetermined second threshold, it is determined that the refrigerant is overfilled; 2. A vehicle air conditioner comprising: a first threshold value and a second threshold value which are changed depending on whether the engine is in a warm-up state or a cold-up state.

2. The vehicle air conditioning device further comprises: a reference threshold map indicating a reference threshold determined by the outside air temperature; a correction value map indicating a correction value for correcting the reference threshold value, The refrigerant state determination unit is determining the first and second threshold values ​​based on the reference threshold map when the engine is in a cold state; 2. The air conditioner for a vehicle according to claim 1, wherein the first threshold value and the second threshold value are determined based on the reference threshold value map and the correction value map when the engine is in a warm-up state.

3. the correction value of the correction value map is determined in accordance with a temperature difference between the engine temperature and an outside air temperature, The refrigerant state determination unit is When the temperature of the engine is equal to the outside air temperature, the engine is determined to be in a cold state; 3. The air conditioning system for a vehicle according to claim 2, wherein the engine is determined to be in a warmed-up state when the temperature of the engine is higher than the outside air temperature.

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