WO2000059748A1

WO2000059748A1 - Safety device for vehicle air conditioning system

Info

Publication number: WO2000059748A1
Application number: PCT/JP1999/001746
Authority: WO
Inventors: Tatsuo Haraguchi; Kiyoshi Tanda
Original assignee: Bosch Automotive Systems Corporation
Priority date: 1999-04-02
Filing date: 1999-04-02
Publication date: 2000-10-12

Abstract

A safety device for an air conditioning system for detecting quickly and positively carbon dioxide leakage and controlling increase in a carbon dioxide concentration in a vehicle otherwise caused by leaked carbon dioxide, comprising a carbon dioxide concentration detector (13) disposed in the vicinity of, and on the downstream side of, an evaporator (12) and an alarm (51) for announcing carbon dioxide leakage when the detector (13) detects that a carbon dioxide concentration has exceeded a preset value to inform carbon dioxide leakage from the evaporator (12), wherein, when a carbon dioxide concentration exceeding a preset value is detected, an intake door (5) is forced into an outside air introduction mode, a compressor (8) is stopped and a blower (6) air volume is increased for reduction in an in-vehicle carbon dioxide concentration. In addition, a bypass (15) opened and closed by a bypass door (14) is provided in an air conditioning duct (2) and a carbon dioxide adsorbent (16) is disposed in the bypass.

Description

Description Safety devices for vehicle air conditioners Technical field

The present invention relates to a safety device for a vehicle air conditioner using carbon dioxide as a refrigerant, the safety device being capable of avoiding adverse effects on occupants due to refrigerant leakage. Background art

The supercritical vapor compression cycle disclosed in Japanese Patent Publication No. 7-186002 is composed of at least a compressor, a cooling device, a throttling means, and an evaporator. Examples include ethylene, diborane, ethane, nitric oxide and carbon dioxide.

This supercritical vapor compression cycle is one of the non-fluorocarbon refrigeration cycles replacing the chlorofluorocarbon refrigeration cycle. In particular, refrigeration cycles using carbon dioxide are promising alternatives to the chlorofluorocarbon refrigeration cycle.

However, since the critical point of carbon dioxide is as low as about 31.1 ° C, the outside air temperature may exceed the critical point, especially in summer, and the high pressure line of the refrigeration cycle may be used during the operation of the refrigeration cycle. (Between the compressor and the squeezing means) is a supercritical region. In the supercritical region beyond this critical point, the pressure is determined by the density and the temperature. Even when it exceeds.

As described above, in the above refrigeration cycle, the operating pressure is much higher than in the case of CFCs. If the parts are made thicker to improve the pressure resistance, the weight of the product will increase and the cost will increase, and the heat exchange rate will decrease in the heat exchange part of the cooling device and evaporator. Occurs.

In addition, it is appropriate to use aluminum as the material in order to reduce the weight and improve the heat exchange rate. However, especially in the case of heat exchangers and the like, the pressure resistance is required due to the balance between heat exchange capacity and strength. Considering that, the maximum working pressure of the refrigeration cycle itself is currently limited to 20 MPa.

When the refrigeration cycle configured as described above is installed in a vehicle air conditioner, the compressor, the cooling device, and the throttling means can be arranged in the engine room, but the evaporator is located in the duct of the vehicle air conditioner. If refrigerant leaks from this evaporator, it is expected that carbon dioxide will leak into the cabin through the air conditioning duct, and the concentration of carbon dioxide in the cabin will be reduced to the specified amount. It is not preferable that the above is achieved.

Therefore, an object of the present invention is to provide a safety device for an air conditioner for a vehicle, which detects leaks of carbon dioxide quickly and reliably and suppresses an increase in the concentration of carbon dioxide in a vehicle cabin due to the leak of carbon dioxide. . Disclosure of the invention

For this reason, the vehicle air conditioner according to the present invention includes an air conditioning duct, an outside air introduction port and an inside air introduction port that are opened on the most upstream side of the air conditioning duct, and selectively the outside air introduction port and the inside air introduction port. An opening door, a blower provided downstream of the intake door, and a carbon dioxide disposed at the downstream side of the blower and used as a refrigerant together with at least a compressor, a radiator, and expansion means. An evaporator constituting a refrigeration cycle, wherein the evaporator comprises: At least a temperature control means for controlling the temperature of the air passing through the air conditioner to a target temperature by changing a heating amount thereof, and a plurality of air outlets opened to the most downstream side of the air conditioning duct. The safety device comprises: a carbon dioxide concentration detecting means for detecting a carbon dioxide concentration near the downstream side of the evaporator; and an occupant when the carbon dioxide concentration detected by the carbon dioxide concentration detecting means is equal to or more than a predetermined value. It has warning means for issuing a warning.

If the carbon dioxide concentration in the vicinity of the downstream side of the evaporator is equal to or higher than a predetermined value, it can be determined that carbon dioxide has leaked from the evaporator. Therefore, occupants can take safety measures such as stopping the compressor, opening windows, introducing outside air, and evacuating outside the vehicle.

Further, when the carbon dioxide concentration detected by the carbon dioxide concentration detecting means is equal to or more than a predetermined value for a prescribed time, the safety device forcibly shifts the intake door to the outside air introduction mode and stops the compressor. The air conditioner is provided with a means for reducing the concentration of carbon dioxide to increase the air volume of the blower.

As a result, when the carbon dioxide concentration is equal to or more than the predetermined value for the specified time, it is determined that there is a refrigerant leak from the evaporator, and the compressor is stopped to suppress the refrigerant leak and to protect the refrigeration cycle, and further, to prevent the outside air By setting the introduction mode compulsorily and increasing the air volume of the blower, the amount of air blown out of the cabin can be increased to reduce the carbon dioxide concentration in the cabin.

The safety device for the vehicle air conditioner further includes: an evaporator; a bypass passage provided between the temperature control means; a carbon dioxide adsorbent disposed in the bypass passage; Located upstream of A bypass door that opens and closes the bypass passage and guides the air that has passed through the evaporator to the bypass passage; and, when the outside air introduction mode cannot be set in the carbon dioxide concentration reducing means, opens the bypass door. In this case, the apparatus is provided with carbon dioxide concentration reduction preliminary means for adsorbing carbon dioxide from the air passing through the evaporator.

As a result, if it becomes impossible to set the outside air introduction mode due to some trouble with the intake door, the bypass door is opened and the air sucked from the vehicle interior and positively passes through the evaporator. Since it can be guided to the bypass passage and pass through the carbon dioxide adsorbent, and the air after carbon dioxide adsorption can be blown out into the vehicle interior, the carbon dioxide concentration in the vehicle interior can be reduced even if the intake door fails. Can be done. Further, it is desirable that the downstream side opening of the bypass passage is shielded by a thin film that can be broken by the air volume of the blower. As a result, the carbon dioxide adsorbent and the air can be shut off, so that the carbon dioxide normally contained in the air can prevent the carbon dioxide adsorbent from lowering its performance.

Further, in the carbon dioxide concentration reducing means, the prescribed time is desirably set to be long when the detected value of the carbon dioxide concentration is low, and set short when the detected value of the carbon dioxide concentration is high.

As a result, the adverse effects of carbon dioxide can be prevented more accurately.

Still further, the safety device for the vehicle air conditioner includes a pressure detection unit that detects a pressure of the refrigeration cycle, and stops the compressor when a pressure detected by the pressure detection unit is equal to or less than a predetermined value. And a compressor stopping means. As a result, the entire refrigeration cycle Since it is possible to detect the leakage of the refrigerant at the time, the compressor can be stopped to protect the refrigeration cycle. It is desirable to trace the pressure on the low pressure side as the refrigeration cycle pressure. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram showing a configuration of a vehicle air conditioner according to the present invention, FIG. 2 is a front view showing an example of an operation panel, and FIG. 3 and FIG. Fig. 5 is a flow chart showing the control of the safety device of the air conditioner for air conditioning. Fig. 5 is a characteristic diagram for calculating the specified time. In Fig. 6, (a) shows the emission of CO2 in the inside air circulation mode (REC). It is a characteristic diagram showing the relationship between the time since the carbon leak and the carbon dioxide concentration, and (b) shows the relationship between the time from the carbon dioxide leak and the carbon dioxide concentration in the outside air introduction mode (FRESH). FIG. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings.

The vehicle air conditioner 1 shown in FIG. 1 has an air conditioning duct 2 arranged on the vehicle interior side. At the most upstream side of the air conditioning duct 2, an outside air inlet 3 communicating with the outside of the vehicle and an inside air inlet 4 communicating with the cabin are opened, and are selectively opened and closed by an intake door 5.

A blower 6 is arranged downstream of the intake door 5, and the air-conditioning duct 2 sucks outside air or inside air from the outside air introduction port 3 or the inside air introduction port 4 opened by the intake door 5. It is sent downstream of On the downstream side of the blower 6, an evaporator 12 constituting a refrigeration cycle 11 together with a compressor 8, a condenser 9, and an expansion valve 10 driven via an electromagnetic clutch 7 is arranged. The refrigeration cycle 11 uses carbon dioxide as a supercritical refrigerant, and the compressor 8, the capacitor 9, and the expansion valve 10 are arranged in an engine room (not shown).

A carbon dioxide concentration detection sensor 13 is disposed near the downstream side of the evaporator 12. Since most refrigerant leakage in the cabin of the refrigeration cycle 11 occurs at or around the evaporator 12, it is desirable to arrange the carbon dioxide concentration detection sensor 13 near the downstream side of the evaporator 12. It is a thing. Thus, the carbon dioxide concentration detection sensor 13 can quickly and surely detect a refrigerant leak from the evaporator 12.

A bypass passage 15 opened and closed by a bypass door 14 is provided downstream of the carbon dioxide concentration detection sensor 13. A carbon dioxide adsorbent 16 is disposed in the bypass passage 15, a shielding film 18 is disposed in the downstream opening 17, and the carbon dioxide adsorbent 16 is disposed in the bypass door 1 on the upstream side. At 4 on the downstream side, it is shielded from surrounding air by a shielding film 18.

The bypass door 14 operates to open the upstream side of the bypass passage 15 and close the air-conditioning duct passage 19 formed in parallel with the bypass passage 15. .

A heater core 20 that uses engine cooling water as a heat source is disposed downstream of the bypass passage 15, and air that has passed through the air conditioning duct passage 19 is disposed upstream of the heater core 20. Heat and air passing through heater core 20 An air mix door 21 is provided for diverting air to bypass the tacho 20.

As a result, the air cooled through the evaporator 12 is diverted at a predetermined ratio into the air passing through the heater core 20 and the air passing by the bypass according to the opening of the air mixing door 21, and the heater core 2 On the downstream side of 0, the air heated by passing through the heater core 20 and the cooled air bypassing the heater core 20 are mixed at a predetermined ratio, so that air at a desired temperature can be obtained. Can be done.

At the most downstream side of the air conditioning duct 2, there are a differential air outlet 22, a vent air outlet 23, and a foot air outlet 24, which are selected by the mode doors 25a, 25b, 25c. The opening is designed to be opened.

The vehicle air conditioner 1 having the above-described configuration includes control devices, for example, an actuator 5a for driving the intake door 5, a motor 6a for the blower 6, an electromagnetic clutch 7, and an actuator for driving the bypass door 14. 14a, an actuator 21a for driving the air-mix door 21 and an actuator 25d for driving the mode doors 25a, 25b, 25c. A control unit (CZU) 30 is provided.

The control unit 30 includes at least a central processing unit (CPU), a read-only memory (R〇M), a random access memory (RAM), an input / output port (I / O), etc. (not shown). At least the known carbon dioxide concentration detection sensor 13, the pressure sensor 31 for detecting the pressure on the low pressure side of the refrigeration cycle 11, the temperature sensor 32 for detecting the outside air temperature, and the temperature in the passenger compartment A signal from the temperature sensor 33 is input through the multiplexer (MPX) 34 and the AZD converter 35, and a setting signal from the operation panel 40 described below is input. After being processed, it is output to the control device as an appropriate control signal.

The operation panel 40 includes a REC switch 41 for manually setting the intake door 5 to the inside air circulation mode or the outside air introduction mode, and a vent for manually opening the vent mode only the vent outlet 23. MODE switch 4 that sets the outlet mode, the foot outlet mode that opens only the foot outlet 24, and the bi-level mode that opens the vent outlets 23 and 24 at a specified ratio 2, a FAN switch 43 for manually setting the air volume of the blower 6 in four stages, and a temperature setting device 44 consisting of an up-down switch 44 a and 44 b for setting the target temperature in the cabin. The DEF switch 45 that opens the differential air outlet 22 to prevent fogging of the front glass (not shown), the OFF switch 46 that stops the operation of the air conditioner itself, and the air conditioner AZC Sui An AUTO switch 49 comprising a switch 47 and an ECON switch 48 for executing economical air-conditioning control, and a display section 50 for displaying the setting status of these switches or the current air conditioning status automatically. A warning indicator 51 that lights up when the carbon dioxide concentration in the vehicle interior is equal to or higher than a predetermined value.

Hereinafter, the safety control performed by the controller unit 30 will be described with reference to the flowcharts shown in FIGS. 3 and 4.

The safety control started from step 100 is the main control

—It is determined that it is the first time that the vehicle is switched on (IG〇N for the first time?). Proceeding to step 120, it is determined whether the detection value S out of the carbon dioxide concentration detection sensor 13 is equal to or greater than a predetermined value Kr. In this determination, if the detected value of carbon dioxide concentration S out is equal to or greater than the predetermined value Kr, the process proceeds to step 130 to turn on the warning display 51 of the operation panel 40, and the main control is started from step 140. Return to routine.

As shown in FIGS. 5 (a) and 5 (b), the prescribed value Kf is desirably set to a value larger than the rise L3 and L6 of the carbon dioxide due to the occupant's exhalation.

As a result, it is possible to visually check that the carbon dioxide concentration is equal to or higher than the predetermined value immediately after getting on the vehicle, so that measures such as opening windows and evacuating outside the vehicle can be taken.

Further, if the carbon dioxide concentration S out is smaller than the predetermined value K r in the determination in step 120, the process returns from step 140 to the main control routine, bypassing step 130.

If it is determined in step 110 that the ignition switch has not been turned on for the first time, the operation proceeds to step 150 to drive the air conditioner (A / C), and the operation proceeds to step 160. Then, it is determined whether or not the low pressure Ps of the refrigeration cycle 11 detected by the pressure sensor 31 is equal to or higher than a predetermined pressure Kp. In this determination, if the low pressure Ps is lower than the predetermined pressure Kp, it is determined that there is a refrigerant leak, and the process proceeds to step 170 to shut off the electromagnetic claim 7 and stop the compressor 8. Then, the flow returns to the main control routine from step 180.

Thus, when a refrigerant leak occurs in the refrigeration cycle 11, the compressor 8 can be stopped, so that each component of the refrigeration cycle 11 can be protected from a trouble due to idling.

If the low pressure Ps is equal to or more than the predetermined value Kp in the determination at the step 160, the process proceeds to the step 190 and the carbon dioxide concentration S out It is determined whether or not is greater than or equal to a predetermined value Kr. If it is greater than or equal to the predetermined value Kr, the process proceeds to step 200 to determine whether or not “1” is set in the timer t setting flag (FL AG 1). Since it is not set for the first time, the timer t is started in step 210 and the timer t setting flag (FLAG1) is set to "1" in step 220. In step 230, the specified time Tr is calculated.

As shown in FIG. 6, the specified time Tr is set by the value of the carbon dioxide concentration Sout, and is long when the value of the carbon dioxide concentration Sout is low, and is high when the value of the carbon dioxide concentration Sout is high. In this case, it is set to be shorter. This is to enhance safety from the relationship between carbon dioxide concentration and exposure time.

If FLAG 1 is set to “1” in step 200, the timer t continues counting, and steps 210, 220, and 230 are avoided. It has become.

Then, the process proceeds to step 240 via the connector A, and it is determined whether or not the timer t has become equal to or longer than the specified time Tr. In this determination, if the timer t has not reached the specified time Tr, the process proceeds to step 320 to return to the main control routine, and in the determination of step 240, the timer t has exceeded the specified time. If so, proceed to step 250 to determine whether or not it is in the outside air introduction mode (FRESH MOD E?). If it is in the outside air introduction mode, proceed to step 290 to stop the compressor 8 In step 300, the blower 6 is operated at a high speed (HIGH) to blow outside air into the vehicle interior to reduce the carbon dioxide concentration in the vehicle interior. Then, the warning display 51 is turned on in step 310, and the process returns to the main control routine from step 320. Things.

If it is determined in step 250 that the current mode is not the outside air introduction mode, the process proceeds to step 260 to move the intake door 5, and the internal air circulation mode (REC mode) is determined in step 260. ), It is determined that the mode has shifted to the outside air introduction mode (FRESH), the process proceeds to step 290, and the control of step 290 and subsequent steps is executed. As a result, as shown in Fig. 6 (b), in the outside air introduction mode (FRESH), the carbon dioxide concentration decreases with the passage of time. However, it is possible to reduce the time during which the carbon dioxide concentration S out is equal to or higher than the specified value K r. In FIG. 6 (b), L4 is the case of a rapid refrigerant leak, L5 is the case of a slow refrigerant leak, and L6 is the carbon dioxide concentration due to exhalation. Also, Tr 3 indicates the time when the carbon dioxide concentration Sout in the vehicle compartment exceeds the specified value r in the case of a sudden refrigerant leak, and TR 4 indicates the carbon dioxide concentration in the vehicle compartment in the case of a slow refrigerant leak. Indicates the time when Sout has exceeded the specified value Kr.

However, if it is determined in step 270 that the intake door 5 has not been driven for some reason and the mode has not been shifted to the outside air introduction mode, the process proceeds to step 280 to proceed to step 280. Drive 14 to open the bypass passage 15 and close the air conditioning duct passage 19 to operate the adsorption system (ON). Then, the process proceeds to step 290 to execute the control in step 290 and lower.

As a result, if the intake door 5 is not driven, as shown in Fig. 5 (a), in the case of the inside air circulation mode (REC), the concentration of carbon dioxide in the vehicle interior is very small. Active operation of adsorption system In addition, it removes carbon dioxide from the intake air to lower the concentration of carbon dioxide in the cabin. In FIG. 5 (a), L1 indicates a rapid refrigerant leak, L2 indicates a slow refrigerant leak, and L3 indicates a change in carbon dioxide concentration due to exhalation. Trl indicates the time when the carbon dioxide concentration Vout in the vehicle compartment exceeds the specified value Kr in the case of a sudden refrigerant leak, and Tr2 indicates the time in the vehicle compartment in the case of a slow refrigerant leak. Indicates the time when the carbon oxide concentration V out exceeds the specified value Kr.

In the above control, when the carbon dioxide concentration S out becomes smaller than the predetermined value K r, the process proceeds from the determination of step 190 to step 330, the timer t is reset, and the FLAG 1 is set to FLAG 1 in step 340. "0" is set, and the process returns to the main control routine from step 350.

As a result, Step 190 to Step 330, Step 340, and Step 350 are repeated until a refrigerant leak is detected in the determinations of Step 160 and Step 190. Things. Industrial applicability

As described above, the safety device for a vehicle air conditioner according to the present invention is provided with the carbon dioxide concentration detection means near the downstream of the evaporator arranged in the air conditioning duct arranged in the vehicle interior. Can quickly and reliably detect the leakage of refrigerant from the vehicle, and if this detection result is abnormal, it can warn the occupants, so vehicles using carbon dioxide as refrigerant The safety of the air conditioner can be improved. If the carbon dioxide concentration is abnormal, the compressor is stopped, the outside air introduction mode is forcibly set, and the air volume of the blower is increased, so that the carbon dioxide concentration in the cabin is reduced. To make Can be done.

When it is not possible to set the outside air introduction mode, the bypass passage is opened, and the carbon dioxide contained can be removed by passing the sucked inside air through the carbon dioxide adsorbent arranged in the bypass passage. Therefore, the concentration of carbon dioxide in the passenger compartment can be reduced, and the safety of the vehicle air conditioner can be further improved.

Claims

The scope of the claims

1. An air-conditioning duct, an outside air inlet and an inside air inlet opening at the most upstream side of the air-conditioning duct, an intake door selectively opening the outside air inlet and the inside air inlet, and the inlet A blower provided downstream of the door, an evaporator arranged downstream of the blower and constituting a refrigeration cycle using carbon dioxide as a refrigerant together with at least a compressor, a radiator, and an expansion means; A vehicle air conditioner having at least a temperature control means for controlling a temperature to a target temperature by changing a heating amount of air passing through an evaporator, and a plurality of air outlets opened at the most downstream side of the air conditioning duct. A carbon dioxide concentration detecting means for detecting a carbon dioxide concentration near the downstream side of the evaporator;

A safety device for a vehicle air conditioner, comprising: warning means for issuing a warning to an occupant when the carbon dioxide concentration detected by the carbon dioxide concentration detecting means is equal to or higher than a predetermined value.

2. If the carbon dioxide concentration detected by the carbon dioxide concentration detecting means is equal to or greater than a predetermined value for a prescribed time, the intake door is forcibly shifted to an outside air introduction mode, the compressor is stopped, and the air volume of the blower is reduced. The safety device for a vehicle air conditioner according to claim 1, further comprising a carbon dioxide concentration reducing means for increasing the concentration.

3. The vehicle air conditioner further comprises: an evaporator; a bypass passage provided between the temperature control means;

A carbon dioxide adsorbent disposed in the bypass passage;

A bypass door disposed upstream of the bypass passage, for opening and closing the bypass passage, and guiding air that has passed through the evaporator to the bypass passage; When the outside air introduction mode cannot be set in the carbon dioxide concentration reducing means, the bypass door is opened, and a carbon dioxide concentration decreasing preliminary means for adsorbing carbon dioxide from air passing through an evaporator is provided. A safety device for a vehicle air conditioner according to claim 2, characterized in that:

4. The safety device for a vehicle air conditioner according to claim 3, wherein the downstream side opening of the bypass passage is shielded by a thin film that can be damaged by an air volume of a blower.

5. In the carbon dioxide concentration reducing means, the prescribed time is set to be long when the detected value of the carbon dioxide concentration is low and to be short when the detected value of the carbon dioxide concentration is high. A safety device for a vehicle air conditioner according to paragraph 2, 3, or 4.

6. Pressure detecting means for detecting the pressure of the refrigeration cycle,

The vehicle according to any one of claims 1 to 3, further comprising: a compressor stop unit that stops the compressor when the pressure detected by the pressure detection unit is equal to or less than a predetermined value. Safety device for air conditioner.