JP2006306294A - Air conditioning device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning device for a vehicle capable of preventing a concentration of refrigerant from being increased in a cabin. <P>SOLUTION: The air conditioning device has a detection means capable of detecting leakage of a combustible refrigerant at the downstream of an evaporator or in the cabin. When the leakage of the combustible refrigerant is detected by the detection means, a control means of the air conditioning device drives a motor for switching between inside air and outside air, and forcibly switches an air introduction mode to an outside air introduction mode. The outside air introduction mode is the mode which performs the outside air introduction from the outside air, and at the same time, opens the exhaust port for preventing the increase of the pressure in the cabin. The control means forcibly operates a blower 4, and switches the blow-out port feeding the air into the cabin into the blow-out port in the direction of the occupant's upper body or the blow-out port for a window or combination of both blow-out ports. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a vehicle air conditioner, and more particularly, to a vehicle air conditioner that suppresses an increase in refrigerant concentration in a passenger compartment and prevents ignition and explosion when a flammable refrigerant leaks. Relates to the device.

  2. Description of the Related Art Conventionally, in a refrigerant circuit of an air conditioner configured by circulating a refrigerant through an evaporator and a condenser, etc., a refrigerant sealed from a refrigeration device such as a connection part of a pipe constituting the refrigerant circuit, an evaporator or a condenser May leak.

  By the way, it is preferable to use an HFC refrigerant having a small global warming potential (GWP) as the refrigerant to be circulated in the refrigerant circuit in consideration of suppression of global warming. In various refrigerants with small GWP, for example, combustible refrigerants also exist.

  It is not preferable that the flammable refrigerant leaks into the room and the refrigerant concentration in the room increases. As a technology for that, when a refrigerant leak is detected, a technique for diffusing the leaked refrigerant by blowing air, a technique for forcibly opening a refrigerant circuit located outside the room, and releasing the refrigerant to the outdoor atmosphere, or an indoor refrigeration equipment The technique etc. which interrupt | block the refrigerant path of this are disclosed (for example, patent document 1, 2).

JP 2000-203243 A JP 2004-1670 A

  However, the flammable refrigerant stays in the vehicle interior in the highly sealed vehicle interior simply by blowing air. Further, in order to forcibly open or shut off the refrigerant circuit, there is a problem that an increase in parts such as a solenoid valve occurs.

  Therefore, the present invention has been made in view of the above, and provides a vehicle air conditioner that is free from the above-described problems and that can prevent an increase in refrigerant concentration in the passenger compartment when a flammable refrigerant leaks. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, an air conditioning apparatus for a vehicle according to the present invention includes a refrigerant having a specific gravity larger than air and flammability, and an evaporator. A refrigerant circuit that circulates the refrigerant, a blower that blows temperature-controlled air into the vehicle interior through the evaporator, and a detection unit that is provided downstream or in the vehicle interior of the evaporator and detects leakage of the refrigerant. When the refrigerant leak is detected by the detection means, the air introduction mode of the blower is forcibly set to the outside air introduction mode, the blower is forcibly operated, and the blower outlet blows air into the vehicle interior. Is forcibly switched to a passenger upper body direction outlet, a window outlet, or a combination of both outlets.

  In general, the air introduction mode of the blower includes an indoor circulation mode and an outside air introduction mode. In the present invention, when the detector detects refrigerant leakage, the control means sets the air introduction mode of the blower to the outside air introduction mode and drives the blower to blow air. Even if the air is simply blown by the blower, if the refrigerant is leaking from the evaporator of the refrigerant circuit or its surroundings when the air introduction mode is the indoor circulation mode, the leakage refrigerant concentration in the air blown into the vehicle compartment increases. On the other hand. However, if the air introduction mode is changed to the outside air introduction mode, fresh air is taken in and exhausted, so that an increase in the leakage refrigerant concentration in the air blown into the passenger compartment can be suppressed.

  Further, according to the present invention, when refrigerant leakage occurs in the passenger compartment, an occupant upper body direction outlet, a window outlet, or a combination of both is adopted as the outlet, and the combustible refrigerant mixture is disposed in the passenger compartment. Blow out above. Thereby, even if it is a leaking refrigerant with larger specific gravity than air, a density | concentration increase can be prevented, without stagnating locally below a vehicle interior.

  Further, the vehicle air conditioner according to the present invention includes a notifying unit for notifying the passenger of the refrigerant leakage when the control unit detects the refrigerant leakage by the detecting unit. It is what I did.

  When refrigerant leaks from the refrigerant circuit, the best action to be taken by the occupant is to stop the compressor or engine, open the window or door, or leave the spot. In order to take these measures, a means for first informing the passenger that the refrigerant has leaked is necessary. As the notification means, it is possible to employ lighting of a dashboard panel lamp, notification by sound or voice from a speaker, application of vibration to a seat, or a combination thereof.

  The vehicle air conditioner according to the present invention is such that, in the vehicle air conditioner, the control means forcibly opens the electric window of the vehicle when the detection means detects the leakage of the refrigerant. It is a thing.

  According to this invention, when the detector detects refrigerant leakage, the control means opens an electric window such as an electric side window of the vehicle. Thereby, even if it continues driving | running | working, ventilation is accelerated | stimulated and even if a refrigerant | coolant leaks, the raise of the refrigerant | coolant density | concentration in a vehicle interior can be prevented.

  Further, the vehicle air conditioner according to the present invention is the vehicle air conditioner, wherein the control means sets the temperature control door to a maximum cooling capacity position when the detection means detects leakage of the refrigerant. It is what you do.

  According to the present invention, the air pressure loss due to the passage of the heater is eliminated, in other words, the temperature adjustment door opening is controlled at the position where the energy loss of the blower is the smallest, so that the ventilation can be performed efficiently.

  According to the vehicle air conditioner of the present invention, it is possible to prevent an increase in refrigerant concentration in the passenger compartment when refrigerant leakage occurs without adding extra components. In particular, a vehicle air conditioner suitable for a refrigerant circuit using a flammable refrigerant can be realized.

  Embodiments of a vehicle air conditioner according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic structural diagram showing an HVAC (Heating Ventilating and Air-conditioning System) of a vehicle air conditioner. The HVAC 1 is a unit in which an outside air inlet 2 and an outlet 3 are opened, and a blower 4, an evaporator (not shown), and a heater (not shown) are included. A switching valve for selecting whether to introduce air from inside the vehicle or from outside the vehicle is opened and closed by the inside / outside air switching motor 5 at the outside air introduction port 2. In addition, a blow-out mode switching motor 6 opens and closes a blow-out port switching valve that can select which one of the plurality of ducts that are communicated thereafter flows to which duct the temperature is controlled.

  FIG. 2 is a cross-sectional view showing the internal structure of the HVAC and the air flow. As described above, the outside air introduction port 2 is connected to the outside air duct 7 through which air from the outside of the vehicle enters and the inside air duct 8 through which air from the inside of the vehicle flows and is switched by the switching valve 9 that rotates at the branch point. Is selected. The air introduced from either one of the ducts flows downstream by a blower 4 such as a sirocco fan that is rotated by the motor 11 downstream thereof. An evaporator 12 is provided downstream thereof. The evaporator 12 is one element which comprises a refrigerant circuit with a compressor, a condenser, and an expansion valve similarly to a general air conditioning apparatus. The air that has passed through the evaporator 12 decreases in temperature and flows downstream.

  A heater 13 is provided downstream of the evaporator 12. As the heater 13, a vehicle radiator coolant is used to exchange heat, or an independent electric heater is used. When passing through the heater 13, the air becomes hot. A temperature control door 14 is slidably provided between the evaporator 12 and the heater 13. The temperature control door 14 adjusts the mixing ratio of cold air and hot air by this slide. As described above, the air whose temperature is controlled by the evaporator 12, the heater 13, and the temperature control door 14 is branched into a plurality of ducts 15, 16, and 17 on the downstream side. Which of these ducts is used is determined by opening and closing the rotary valves 18 and 19. For example, the rotary valve 18 can control opening and closing of the duct in the foot direction, and the rotary valve 19 can control opening and closing of the duct 16 to the passenger upper body direction outlet and the duct 17 to the window outlet.

As the refrigerant circulating in the refrigerant circuit of the air conditioner, a flammable refrigerant may be used as a refrigerant having a small GWP in consideration of prevention of global warming. Therefore, the present invention is directed to a vehicle air conditioner in which a combustible refrigerant is employed as the refrigerant in the refrigerant circuit. For example, HFC (CHF ₂ CH ₃ ) refrigerants such as R-152a and fluoromethane have a small GWP and are said to be effective for air conditioners. This flammable refrigerant has a feature that it has a specific gravity greater than that of air, and if the refrigerant leaks into the vehicle from the vicinity of the evaporator, it is likely to accumulate near the floor of the vehicle.

  The air-conditioning apparatus according to the present invention has detection means 34 (see FIGS. 14 and 15) capable of detecting leakage of the combustible refrigerant downstream of the evaporator or in the passenger compartment. Specifically, the semiconductor type gas concentration sensor shown in FIG. 10 using the semiconductor type gas concentration detection element shown in FIG. 9, the catalytic combustion type gas concentration detection element shown in FIG. 11, or the expected thermal conductivity type gas concentration detection element shown in FIG. 12 is used for the bridge circuit, an expected thermal conductivity gas concentration sensor, an evaporator temperature detection thermistor conventionally used, and the like. When the leakage of the flammable refrigerant is detected by the detection means 34 provided as low as possible, the control means of the air conditioner drives the inside / outside air switching motor 5 to forcibly introduce the air introduction mode. Enter mode. Here, the outside air introduction mode is a mode in which, as shown in FIG. 3, air is introduced from outside air, and at the same time, an outlet (outlet) 20 for preventing an increase in vehicle interior pressure is opened. The control means will be described later.

  In general, the air introduction mode of the blower includes an indoor circulation mode and an outside air introduction mode. Even if the air is simply blown by the blower, if the refrigerant is leaking from the evaporator of the refrigerant circuit or its surroundings when the air introduction mode is the indoor circulation mode, the leakage refrigerant concentration in the air blown into the passenger compartment increases. On the other hand. However, if the air introduction mode is the outside air introduction mode, fresh air is taken in, diffused into the vehicle compartment, and discharged from the exhaust port, so that an increase in the leakage refrigerant concentration in the air blown into the vehicle compartment can be suppressed.

  In addition, the control means of the present invention forcibly operates the blower 4, and forcibly sets the air outlet for blowing air into the passenger compartment of the occupant upper body direction outlet, the window outlet, or both outlets. Switch to a combination. As shown in FIGS. 4 and 5, the air from the occupant upper body direction duct 16 of FIG. 2 is provided to the passenger upper body direction outlet 25 provided on the dashboard of the vehicle, and the window duct of FIG. Air from 17 is sent. The outlet may be switched to either one, or air may be blown out at a predetermined rate from both. In any case, it is important to prevent local stagnation by blowing out air containing a flammable refrigerant toward the upper side of the passenger compartment.

  Moreover, you may make it determine whether a duct is selected by indoor temperature or external temperature. For example, if it is about 30 degrees Celsius in summer, the occupant tends to feel hot, so select the occupant upper body direction outlet 25, and if it is about 5 degrees Celsius in winter, select the window outlet 26 that does not directly hit the occupant. To do. In specific control, an appropriate temperature threshold may be set.

  If it does in this way, as shown in FIG. 8, combustible refrigerant | coolant air-fuel | gaseous mixture can be blown out upwards of a vehicle interior. As a result, the combustible refrigerant having a specific gravity greater than that of air accumulates and stays in the lower part of the passenger compartment, and an increase in concentration can be prevented. Since the explosion of the combustible refrigerant depends on its concentration (for example, in the case of HFC-152a, the lower explosion limit is 4.0 vol%), the diffusion of the leaked refrigerant upward as described above is This is extremely effective because it prevents a local concentration increase at the bottom.

  In addition, since HFC-152a and the like have a characteristic of extremely low inhalation toxicity, even if an air outlet in the direction of descending to the occupant is selected, there is an effect of the present invention, and it is considered that an intoxication symptom is immediately caused. Hateful. Therefore, the present invention is also effective from this viewpoint. Furthermore, in many current vehicles, when air is sent out from the foot outlet, it is often used during heating, so the outside air intake duct of the HVAC is throttled. That is, the present invention that uses the occupant upper body direction outlet without restricting the outside air intake duct is superior to the method of blowing out under the foot in terms of ventilation.

  In addition, the control means in the present invention includes notification means for notifying the occupant of refrigerant leakage when the detection means 34 detects leakage of the refrigerant. If refrigerant leaks from the refrigerant circuit, the best action to be taken by the passenger is to stop the compressor or engine, open the window or door, and at least avoid fire. In order to do so, a means for first informing the passenger that the refrigerant has leaked is required. As the notification means, it is possible to employ lighting of a dashboard panel lamp, notification by sound or voice from a speaker, application of vibration to a seat, or a combination thereof.

  The control means in the present invention includes control means for forcibly opening electric windows such as electric side windows and electric sunroofs of the vehicle when refrigerant leakage is detected. Specifically, the control means applies a predetermined voltage to the motor that controls the opening and closing of the electric window. Thereby, even if it continues driving | running | working, ventilation is accelerated | stimulated and even if a refrigerant | coolant leaks, the raise of the refrigerant | coolant density | concentration in a vehicle interior can be prevented. The opening ratio of the side window may be determined according to the traveling speed of the vehicle. For example, when the traveling speed is 0 km / h, the opening is relatively large, and when the traveling speed is 30 km / h or more, only about 10% of the whole is opened.

  Moreover, the control means in this invention makes the temperature control door opening the maximum cooling capacity when the refrigerant leakage is detected. That is, the temperature control door 14 in FIG. 2 is slid to a position where the heater 13 is hidden. Thereby, since the temperature control door opening degree is controlled to the position where the energy loss (pressure loss) of the blower is the smallest, ventilation can be performed efficiently.

  Here, an example of the control flow of the control means (device) according to the present invention will be described. FIG. 6 is a flowchart illustrating an example of a control flow. The control flow starts from a refrigerant leakage check by the detection means 34 (steps S101 and S102). If there is no refrigerant leakage, this loop is repeated. When refrigerant leakage is detected, it is determined whether cooling of the air conditioner is in operation (step S103). If not in operation, the blower is operated to forcibly blow air (step S104). If in operation, the compressor is stopped to stop refrigerant circulation (step S105).

  Then, a warning or the like is notified to the passenger that refrigerant leakage has occurred (step S106). In this example, the selection of the outlet uses the outside air temperature (step S107). Specifically, for example, if the outside air temperature is lower than 20 ° C., the air blowing toward the occupant is cold and uncomfortable, so the DEF mode using the window direction outlet is set (step S110). On the contrary, if it is higher than 20 ° C., the occupant can easily feel the heat, so it is preferable to set the FACE mode in which the occupant upper body direction outlet is used only by blowing air (step S108). When the air outlet is in the window direction, the air volume is not large, so it is determined that the temperature control door may be in the conventional position (step S111). If the upper outlet is in the direction of the upper part of the occupant, the temperature control door is slid to a position that covers the heater, eliminating pressure loss when passing through the heater, increasing ventilation efficiency and improving energy efficiency (step) S109).

  Next, the air introduction mode is switched to the outside air mode regardless of whether the air outlet is in the window direction or the occupant upper body direction (step S112). In order to open a window such as a side window or a sunroof, it is better to notify the occupant in advance (step S113). In this example, the degree of opening is determined by the vehicle speed (step S114). If the vehicle speed is 0 km / h, that is, if the vehicle is stopped, the side window etc. is opened 30% (step S116), and if it is more than that, it is opened 10% (step S115). In any case, when the air outlet is in the occupant upper body direction or the window direction, when the side window or the like is opened, the air-fuel mixture containing the leaked refrigerant is efficiently discharged out of the vehicle. When the above operation is performed, the remaining refrigerant amount is detected by the detecting means (step S117). If the remaining refrigerant is a predetermined threshold, for example, Xg or less, the control after step S103 is stopped, and the state of step S101 is resumed. The process proceeds (step S108).

  The control means 30 according to the present invention comprises an input unit 31, a calculation unit 32, and an output unit 33, and new inputs, programs, and outputs are added to the control devices used in the air conditioner and the vehicle itself. This can be realized by adding Specifically, an electric signal indicating the outside air temperature, the vehicle speed, the cooling operation state, etc., such as the concentration from a specific chemical substance concentration meter or the like, is input to the input unit. Then, the calculation unit 32 executes a program for realizing the control flow and the like, and according to the result, the air introduction mode switching valve, the blower ON / OFF, the duct selection valve, the notification / alarm means, the window opening / closing motor, and the temperature control Outputs electrical signals that control door opening and closing.

  The vehicle air conditioner according to the present invention is suitable for production, use, and the like of a vehicle air conditioner that uses a combustible refrigerant as a refrigerant.

It is a perspective view which shows HVAC. It is sectional drawing which shows the structure of HVAC. It is explanatory drawing which shows outside air mode. It is an external view which shows a passenger | crew upper body direction blower outlet. It is an external view which shows the blower outlet for windows. It is a flowchart which shows a control flow. It is a schematic diagram which shows a control means. It is explanatory drawing which shows the flow of the wind in a vehicle interior. It is a structural diagram which shows the structure of a semiconductor type gas concentration detection element. It is a structural diagram showing a configuration of a semiconductor type gas concentration sensor. It is a structural diagram which shows the structure of a catalytic combustion type gas concentration detection element. FIG. 3 is a structural diagram showing the configuration of a catalytic combustion type or expected thermal conductivity type gas concentration sensor. FIG. 3 is a structural diagram showing a configuration of an expected thermal conductivity type gas concentration detecting element. It is HVAC sectional drawing which shows the example of installation of a combustible refrigerant | coolant leak detection means. It is explanatory drawing in a vehicle interior which shows the example of installation of a combustible refrigerant | coolant leak detection means.

Explanation of symbols

1 HVAC
2 Outside air inlet 3 Outlet 4 Blower 5 Inside / outside air switching motor 6 Motor 7 Outside air duct 8 Inside air duct 9 Switching valve 11 Motor 12 Evaporator 13 Heater 14 Temperature control door 18, 19 Rotating valve
20 Outlet
25 Outlet for upper body direction
26 Window outlet 30 Control means
31 Input section
32 Calculation unit
33 Output section
34 Combustible refrigerant leak detection means

Claims (4)

A specific gravity greater than air and a flammable refrigerant;
A refrigerant circuit configured to include an evaporator, and circulate the refrigerant through the evaporator;
A blower for blowing temperature-controlled air into the vehicle compartment through the evaporator;
A detecting means that is provided downstream of the evaporator or in a vehicle compartment and detects leakage of the refrigerant;
When the detecting means detects leakage of the refrigerant, the air introduction mode of the blower is forcibly set to the outside air introduction mode, the blower is forcibly operated, and an air outlet for blowing air into the vehicle interior is provided. Control means for forcibly switching to a passenger upper body direction outlet, or a window outlet, or a combination of both outlets;
An air conditioner for a vehicle, comprising:   2. The vehicle air conditioner according to claim 1, wherein the control unit includes a notification unit that informs an occupant of refrigerant leakage when the detection unit detects leakage of the refrigerant.   The vehicle air conditioner according to claim 1 or 2, wherein the control means forcibly opens an electric window of the vehicle when the detection means detects leakage of the refrigerant.   The vehicle control device according to any one of claims 1 to 3, wherein the control means sets the temperature control door to a maximum cooling capacity position when the detection means detects leakage of the refrigerant. Air conditioner.

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