JPH11254954A - Air conditioner for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the heating performance when the outside air temperature is low by performing a control for operating or stopping a cabin outside evaporator heating means for heating a cabin outside evaporator on the basis of the air temperature on the downstream side of a capacitor within a cabin. SOLUTION: A sub-evaporator 30 as a cabin outside evaporator is arranged between the coolant outlet of a main evaporator 3 and a compressor 6. An air temperature sensor 53 for detecting the air temperature of the flow just under a sub-capacitor 4 is connected to an auto-amplifier which is a control means. In the auto-amplifier, the power supply to a sheath heater for heating the sub-evaporator 30 is controlled on the basis of the air temperature detected by the air temperature sensor 53. According to this, the discharged coolant temperature of the compressor 6 can be prevented from being excessively raised. Thus, a control for reducing the frequency of the compressor 6 can be performed while ensuring the temperature of the blowout air into a cabin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for an electric vehicle having no hot water heat source for heating, and more particularly, to a heat pump type air conditioner for heating the interior of a vehicle cabin utilizing condensation heat generated when refrigerant condenses. The present invention relates to an air conditioner for an electric vehicle that can improve heating performance even when the outside air temperature is low.

[0002]

2. Description of the Related Art An electric vehicle whose driving source is an electric motor has less heat energy as a heat source for heating as compared with a gasoline engine vehicle that can use high-temperature engine cooling water. Therefore, conventionally, as an air conditioner for electric vehicles,
An air conditioning system that enables dehumidifying heating by heating the vehicle interior by performing a cycle operation using a refrigerant for both cooling and heating, a so-called heat pump cycle operation, and heating the vehicle interior while preventing fogging of windows. It has been developed (for example, see JP-A-5-201243).

[0003] In this air conditioner, an evaporator and a sub-condenser working mainly in a heating operation are arranged in order from an upstream side in a duct for sending the taken air toward a passenger compartment, and the duct is mainly provided outside the duct. The main condenser that operates during the cooling operation is provided. And, in the heating operation, the refrigerant discharged from the compressor bypasses the main condenser, and the compressor → the sub condenser →
Refrigerant flows through the route of liquid tank → expansion valve → evaporator → compressor. As a result, the gas refrigerant discharged from the compressor is condensed and liquefied by the sub-condenser and dissipates heat, so that the air cooled and dehumidified by the evaporator is heated and blown out into the vehicle interior, and the vehicle interior is dehumidified and heated. Is done.

[0004]

However, in such conventional air conditioners for electric vehicles, when the outside air temperature is low (for example, when the outside air temperature is 0 ° C. or less), the heating performance tends to be insufficient. In other words, if the temperature of the outside air taken into the duct is low, it is difficult for the evaporator to absorb heat from the intake air, so that the refrigerant is not sufficiently evaporated in the evaporator. Ability). In other words, since there is almost no pumping of heat from the outside in the evaporator, the degree of superheat of the evaporator (superheat) is not ensured, and the work of the compressor becomes almost the same as the heat dissipation capacity of the sub-capacitor (coefficient of performance CO
P ≒ 1). Therefore, when viewed in the entire refrigeration cycle, the heating efficiency is greatly reduced, and the heating performance is insufficient.

[0005] For this reason, it is necessary to supplement the capacity necessary for heating. 1. Use electric heater heating together 2. Water is heated by a heater and heating is performed by a heater core. A method of absorbing heat in a refrigerant circulating in a cycle and dissipating heat in an air conditioner system can be considered.

[0006] 1. Although the method described above is simple, a large current or a high voltage is introduced into the passenger compartment, and there is a drawback in that a new vehicle safety measure is required. Also, 2. Although the above method is relatively simple, it has a disadvantage that another heat exchanger must be separately installed in the vehicle interior.

Therefore, the applicant of the present invention has described the above 3. An air conditioner for an electric vehicle employing the above method has already been proposed (see Japanese Patent Application No. 9-11417). That is, an air conditioner for an electric vehicle has been proposed in which an outside evaporator is disposed between a refrigerant outlet of a vehicle interior evaporator and a refrigerant suction port of the compressor, and heating means for heating the external evaporator is provided. Thereby, even when the outside air temperature is low, it is possible to always have an appropriate degree of superheat (superheat) at the outlet of the evaporator outside the vehicle compartment, and it is possible to improve the heating performance.

However, when the heating means heats the evaporator outside the vehicle compartment to perform the heating operation, the temperature of the refrigerant discharged from the compressor rises to a certain temperature or higher, and the compressor for suppressing such a rise in refrigerant temperature. In some cases, control for lowering the frequency was activated.
For this reason, there has been a problem that the improvement of the heating performance is hindered as a result.

The present invention has been made in view of the above-mentioned problems in a heat pump type air conditioner for an electric vehicle having no hot water heat source for heating, and reliably improves the heating performance even when the outside air temperature is low. It is an object of the present invention to provide an air conditioner for an electric vehicle that can achieve the following.

[0010]

In order to achieve the above object, the invention according to claim 1 comprises a compressor, a vehicle exterior condenser, a vehicle interior condenser, which constitute a refrigeration cycle.
The expansion valve and the cabin evaporator are connected in this order by refrigerant piping, and a bypass pipe for guiding the refrigerant discharged from the compressor to the vehicle interior condenser by bypassing the exterior condenser and a discharge pipe from the compressor. Refrigerant flow switching means provided in the refrigerant pipe downstream of the compressor to switch the flow path of the refrigerant to be performed, the refrigerant discharged from the compressor, the cooling medium in the cooling operation by the refrigerant flow switching means In an air conditioner for an electric vehicle, which is introduced into a condenser outside the vehicle compartment and directly introduced into the vehicle interior condenser through the bypass pipe by the refrigerant flow switching means during the heating operation, the refrigerant outlet of the vehicle interior evaporator and the compressor A vehicle exterior evaporator disposed between the refrigerant inlet and the vehicle, An exterior evaporator heating means for heating an exterior evaporator, an air temperature sensor disposed downstream of the interior cabin condenser, and operating or operating the exterior evaporator heating means based on an air temperature detected by the air temperature sensor. And control means for controlling to stop.

According to a second aspect of the present invention, in the air conditioner for an electric vehicle according to the first aspect, the outside-cabin evaporator heating means includes: a heating element that generates heat by supplying power from a vehicle-mounted power supply; A heat transfer medium that transfers heat generated from the body to the outside evaporator, wherein the electric vehicle air conditioner includes an outside air temperature sensor that detects an outside air temperature, and heat transfer that detects a temperature of the heat transfer medium. A medium temperature sensor, wherein the control unit controls to supply or stop the power to the heating element based on the outside air temperature and the temperature of the heat transfer medium.

According to a third aspect of the present invention, in the air conditioner for an electric vehicle according to the first or second aspect, the control means passes through a suction port for taking in air to be sent into a vehicle compartment during a heating operation. The air is controlled such that at least a predetermined ratio selected from at least 30 to 60% of the air is outside air.

[0013] The invention described in claim 4 is the above-mentioned claim 1-
The air conditioner for an electric vehicle according to any one of claims 3, wherein an opening degree of the expansion valve is controlled by sensing a temperature of an outlet pipe from which refrigerant flows out of the vehicle interior evaporator or the vehicle exterior evaporator. An opening control member for heating the opening control member, an opening control member heating means for increasing the opening of the expansion valve, and an opening control member heating for detecting the temperature of the opening control member heating means. Means temperature sensor, wherein the control means controls the opening control member heating means to operate or stop based on the temperature of the opening control member heating means during the heating operation. I do.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an air conditioner for an electric vehicle according to an embodiment of the present invention.
Shows the flow of the refrigerant at the time of heating with a solid line, and (B) shows the flow of the refrigerant at the time of cooling with a solid line.

This air conditioner for an electric vehicle has a duct 2 for sending air (inside air or outside air) taken in by a blower device 1 toward a vehicle interior.
Inside the duct 2, a main evaporator 3 as a vehicle interior evaporator and a sub-condenser 4 as a vehicle interior condenser mainly working during a heating operation are arranged in order from the upstream side. A main condenser 5 serving as a condenser outside the vehicle compartment that works during operation is provided. At one end of the duct 2, inside air and / or
Alternatively, an intake door 16 for taking in outside air is rotatably mounted, and at the other end of the duct 2, a differential outlet for blowing conditioned air to the inner surface of the windshield, and a vent outlet for blowing conditioned air to the upper body of the occupant. Foot outlets for blowing out warm air are provided at the feet of the occupants (both are not shown). An air mix door 15 is rotatably mounted upstream of the sub-condenser 4 to adjust the temperature of the air blown into the vehicle interior. The air mix door 15 adjusts the ratio of the hot air passing through the sub-condenser 4 and the cool air bypassing the sub-condenser 4 to produce air at a desired temperature downstream of the sub-condenser 4 or to allow air to flow through the sub-condenser 4. I try not to.

In the air conditioner of the present embodiment, a sub-evaporator 30 as an evaporator outside the vehicle compartment is disposed between a refrigerant outlet of the main evaporator 3 and a refrigerant inlet of the compressor 6. The sub-evaporator 30 has a vehicle-mounted power supply (not shown) (for example, DC336V).
A sheathed heater unit 31 as a vehicle interior evaporator heating means having a sheathed heater as a heating element that generates heat by supplying power from the vehicle. Regarding the sub-evaporator 30 and the sheathed heater unit 31,
Details will be described later.

The refrigeration cycle constituted by the air conditioner is as follows.
The compressor 6, including the sub-evaporator 30,
The main condenser 5, the sub-condenser 4, the liquid tank 7, the expansion valve 8, and the main evaporator 3 are connected by a refrigerant pipe, and the refrigerant is sealed therein.

In order to switch the condensers 4 and 5 which function between the heating operation and the cooling operation, a four-way valve 10 for switching the flow of the refrigerant is provided at the inlet side of the main condenser 5 as refrigerant flow switching means. Is provided.
The four-way valve 10 is connected to a bypass pipe 11 for bypassing the main condenser 5 and a refrigerant recovery pipe 12 for returning so-called stagnant refrigerant mainly staying in the main condenser 5 to the suction side of the compressor 6. I have. The bypass pipe 11 is connected to a pipe 13 that connects the outlet of the main condenser 5 and the inlet of the sub-condenser 4. Reference numerals 20 to 23 in the figure denote check valves, respectively. On the back of the main condenser 5, a condenser fan device 14 for supplying air for heat exchange to the main condenser 5 is provided.

The inlet port of the four-way valve 10 is connected to the compressor 6
The three output ports of the four-way valve 10 are connected to the inlet of the main condenser 5, the suction side of the compressor 6 (refrigerant recovery pipe 12), and the main condenser 5, respectively.
(Bypass pipe 11). The four-way valve 10 switches between a cooling circuit for guiding the refrigerant discharged from the compressor 6 to the main condenser 5 and a heating circuit for guiding the refrigerant discharged from the compressor 6 to the bypass pipe 11 of the main condenser 5.

The heating circuit has a path indicated by a solid line in FIG. 1A, that is, a path of the compressor 6, the sub-condenser 4, the liquid tank 7, the expansion valve 8, the main evaporator 3, the sub-evaporator 30, and the compressor 6. It is configured. That is, at the time of the heating operation, the four-way valve 10 is set at a position connecting the discharge side of the compressor 6 and the bypass pipe 11, and the refrigerant discharged from the compressor 6 is guided to the bypass pipe 11, and the refrigerant flows along the path. To form a circulating heating cycle. In this circulation process,
Since the gas refrigerant discharged from the compressor 6 is condensed and liquefied by the sub-condenser 4 and radiates heat, the air cooled and dehumidified by the main evaporator 3 is heated and blown out into the vehicle interior, so that the vehicle interior is dehumidified. Heated. At this time, the temperature of the air blown into the vehicle compartment is controlled by adjusting the opening of the air mix door 15.

On the other hand, the cooling circuit has a path indicated by a solid line in FIG. 1B, that is, the compressor 6 → the main condenser 5 → the sub condenser 4 → the liquid tank 7 → the expansion valve 8.
The main evaporator 3 → sub-evaporator 30 → compressor 6 is constituted. That is, during the cooling operation, the four-way valve 10 is set at a position connecting the discharge side of the compressor 6 and the inlet of the main condenser 5,
The refrigerant discharged from the compressor 6 is guided to the main condenser 5 to form a cooling cycle in which the refrigerant circulates along the path. In this circulation process, the main evaporator 3 evaporates the liquid refrigerant by heat exchange and cools the intake air passing around the refrigerant passage, thereby cooling the vehicle interior. Further, the main condenser 5 releases the heat taken by the main evaporator 3 to the outside by exchanging heat with air to cool the gas refrigerant and condense and liquefy it. In addition,
At this time, the heating element in the sheath heater unit 31 attached to the sub-evaporator 30 does not generate heat. The sub-condenser 4 hardly functions as a heat exchanger when the mix door 15 is set to the full cool side.

FIG. 2 is a detailed configuration diagram of the sub-evaporator and the sheathed heater unit shown in FIG. As shown, the sub-evaporator 30 and the sheathed heater unit 31 are housed in a casing 38, and the casing 38 protects the inside and improves the heat retaining effect. Reference numeral 38 in the figure indicates a heat insulating material.

Connection pipes 35a and 35b are attached to both ends of the sub-evaporator 30, respectively. One connecting pipe 35 a is connected to the outlet side of the main evaporator 3, and the other connecting pipe 35 b is connected to the suction side of the compressor 6.

The sheathed heater unit 31 includes a sheathed heater 32 that generates heat by power supply from a vehicle-mounted power supply, and a heat transfer medium that transmits heat generated by the sheathed heater 32 to the sub-evaporator 30. As the heat transfer medium, LLC which is a long-term usable coolant is used.
(Long Life Coolant) 33 is used.

The sheath heater 32 has a heating wire (for example,
This is a heating element in which a coil-shaped nichrome wire) is placed in a protective tube (sheath) and filled with a heat-resistant insulating material in the middle. Here, for example, the heating element is formed in a coil shape. Lead terminals are connected to both ends of the sheath heater 32, respectively, and are connected to a vehicle power supply (for example, DC336V) (neither is shown).

The sheathed heater 32 is provided in a tank 34, and the LLC 33 is sealed in the tank 34.

An inflow connection pipe 41 and an outflow connection pipe 42 are attached to the tank 34, and a circulation path 43 including these connection pipes 41 and 42 and circulating the LLC 33 passes through the inside of the sub-evaporator 30. Is formed. Therefore, in the sub-evaporator 30, the LLC 33 and the refrigerant flow in opposite directions, and heat exchange is performed. A pump 44 for circulating the LLC 33 is provided between the sub-evaporator 30 and the tank 34 in the circulation path 43. As described above, since the pump 44 is disposed on the downstream side when viewed from the position of the sub-evaporator 30, the LLC 33 discharged from the tank 34
Is subjected to heat exchange with the low-temperature and low-pressure refrigerant in the sub-evaporator 30 to lower the temperature. Therefore, it is not necessary to use a heat-resistant material for the pump 44 unnecessarily, and the cost is reduced.

An inlet for injecting the LLC 33 into the tank 34 is provided at an upper portion of the tank 34. The inlet is provided with a pressure regulating valve which operates when the temperature of the internal LLC 33 becomes high temperature and high pressure. Is mounted.

The LLC 33 sealed in the tank 34
A heat transfer medium temperature sensor 45 for detecting the temperature of the heat transfer medium is provided. The heat transfer medium temperature sensor 45 is disposed in a concave portion 34a formed on the side of the tank 34 opposite to the cap mechanism 37 in order to reduce the size of the apparatus.

FIG. 3 is a diagram showing the vicinity of a temperature-sensitive cylinder attached to the outlet pipe of the sub-evaporator, and FIG. 4 is a circuit diagram of heating control of the temperature-sensitive cylinder.

As shown in FIGS. 1 and 3, the temperature of the outlet pipe 18 from which the refrigerant flows out of the sub-evaporator 30 is sensed to control the degree of opening of the expansion valve 8. A warm cylinder 46 is attached.
A temperature-sensitive cylinder heater 47 as an opening control member heating means for heating the temperature-sensitive cylinder 46 to forcibly increase the opening of the expansion valve 8 and an opening for detecting the surface temperature of the temperature-sensitive cylinder heater 47. A heater surface temperature sensor 49 as a temperature control member heating means temperature sensor is provided. As the temperature-sensitive cylinder heater 47, for example, a positive temperature coefficient thermistor is used. These are attached to the temperature-sensitive cylinder 46 via an electric insulating tape T or the like, and are covered with a heat insulating material 48 together with the outlet pipe 18. Therefore, it is possible to secure the flow rate of the refrigerant by heating the temperature-sensitive cylinder 46. During the operation of the sheathed heater 32, the auto amplifier 50 as a control means controls the relay 21 based on the surface temperature of the temperature-sensitive cylinder heater 47.
Is turned on or off, the temperature-sensitive cylinder heater 47 is controlled to operate or stop.

FIG. 5 is a block diagram showing an electrical configuration related to the heating characteristics of the electric vehicle air conditioner.

The auto amplifier 50 as a control means has a function of comprehensively controlling the air conditioner, and has a built-in microcomputer.

The auto amplifier 50 detects a heat transfer medium temperature sensor 45 for detecting the temperature of the LLC 33 in the sub-evaporator 30, an outside air temperature sensor 52 for detecting the outside air temperature, and an air temperature Tsc immediately downstream of the sub-condenser 4. Air temperature sensor 53 (see FIG. 1), heater surface temperature sensor 4
9. Other various sensors such as a compressor frequency detection sensor 58 for detecting the rotation frequency of the compressor 6 are connected. An operation mode determination unit 54 is provided in the auto amplifier 50, and determines whether the operation is heating operation or cooling operation based on the position of the temperature control lever, the various sensors, and the like.

A sheathed heater 32 is connected to the auto amplifier 50 via a sheathed heater driving unit 55, and the LLC 33 heated by the sheathed heater 32 is connected to the auto-amplifier 50.
Is circulated through a pump driving unit 56. The temperature-sensitive cylinder heater 47 described above
Are also connected via a relay 51.

Further, various doors (for example, intake door 16, air mix door,
Various actuators (for example, intake door actuator 57 for driving intake door 16, air mix door 1) for driving various doors for driving mode doors for opening and closing each air outlet
5 and a mode door actuator for driving the mode door. The auto amplifier 50 receives signals from various sensors and the like, calculates these signals, operates the intake door actuator 57 and the like, and comprehensively controls the opening degree of the suction port 19, the position of the air outlet, and the like.

Next, the operation of the electric vehicle air conditioner during heating will be described with reference to FIGS.

FIG. 6 is a control flowchart of the sheathed heater. As shown in FIG. 6, first, during the heating operation (YES in step S1), it is determined whether or not the outside air temperature Ta is equal to or lower than 10 ° C. (step S2).
If a is 10 ° C. or less (YE in step S2)
S), ON / OFF determination of the sheathed heater is performed based on the compressor frequency (step S3).

In this step S3, as shown in FIG. 7, when the frequency increases, the compressor frequency H becomes 70 Hz.
When the compressor frequency H is 60 Hz, the determination is made to change from the on determination to the off determination when the compressor frequency H is 60 Hz.
The compressor frequency H used here is calculated by adding a predetermined correction from the position of the temperature control lever (PTC) and the like. Thus, only when it is necessary to heat the compressor 6 by operating the compressor 6 at a certain frequency or higher, the control for turning on the sheath heater 32 is performed.

If the ON / OFF determination for the sheathed heater based on the compressor frequency in step S3 is an ON determination (YES in step S4), step S5 is performed.
Proceed to. In this step S5, a reference temperature KTsc for ON / OFF determination of the sheath heater 32 based on the air temperature Tsc immediately downstream of the sub-condenser 4 is set. The reference temperature KTsc is set based on a target outlet temperature of the air blown into the vehicle compartment calculated from the temperature adjustment lever position and the like. However, the reference temperature KTsc must be KTsc ≦ 5.
It is set to be 5 ° C.

Next, in step S6, it is determined whether the sheathed heater is on or off based on the air temperature immediately downstream of the sub-condenser. In this step S6, FIG.
As shown in the figure, when the air temperature rises, the air temperature Tsc immediately downstream of the sub-condenser 4 changes from the ON judgment to the OFF judgment when the air temperature Tsc immediately downstream of the sub-condenser 4 is the reference temperature KTsc. Is the reference temperature KTsc
When the temperature is lower by 2 ° C., the determination is made to change from the OFF determination to the ON determination. This prevents the temperature of the refrigerant discharged from the compressor 6 from rising excessively.

If the ON / OFF determination for the sheathed heater based on the air temperature immediately downstream of the sub-condenser in step S6 is an ON determination (YES in step S7)
S), and proceed to step S8. In this step S8, according to the graph shown in FIG.
The reference temperature KTW for ON / OFF determination of the sheathed heater 32 is set based on the temperature Tw of the LC 33.

In step S9, LL corresponding to the outside air temperature
On / off determination of the sheathed heater is performed based on the C temperature. In this step S9, as shown in FIG. 10, when the LLC temperature rises, the temperature Tw of the LLC 32 changes from the on judgment to the off judgment when the temperature Tw is the reference temperature KTW. On the other hand, when the LLC temperature falls, the temperature Tw of the LLC 32 becomes the reference temperature KTW. When the temperature is lower by 10 ° C., the determination is made so as to change from the OFF determination to the ON determination. This allows
An excessive rise in the temperature of the refrigerant discharged from the compressor 6 is more reliably prevented.

If the ON / OFF determination for the sheathed heater based on the LLC temperature according to the outside air temperature in step S9 is an ON determination (YE in step S10).
S), the sheath heater 32 and the pump 44 are turned on (steps S11 and S12).

On the other hand, if NO is determined in steps S1, S2, and S4, both the sheath heater 32 and the pump 44 are turned off. If NO is determined in step S14, the sheath heater 32 is turned off. Although turned off, the pump 44 is set to the on state. Further, when the heat transfer medium temperature sensor 45 and the air temperature sensor 53 fail, the control becomes impossible, so that both the sheathed heater 32 and the pump 44 are turned off (step S13).

The values of the reference temperatures KTsc and KTW can be changed slightly according to specifications and the like.

As described above, since the sub-evaporator 30 is heated by the sheath heater 32 via the LLC 32, the refrigerant is not sufficiently evaporated in the main evaporator 3 even if the outside air temperature is low. Even if the appropriate degree of superheat is not secured at the outlet of the liquid refrigerant or the liquid refrigerant flows out from the main evaporator 3,
In the sub-evaporator 30, the sheath heater 32
As a result, the refrigerant effectively takes in heat and is heated by heat exchange with the LLC 33 which is the heat transfer medium heated by the heating, so that an appropriate degree of superheating can be provided at the outlet of the sub-evaporator 30. Then, the moderately superheated refrigerant is sucked into the compressor 6 and compressed again, so that the refrigerant discharged from the compressor 6 becomes a higher-temperature refrigerant and is supplied to the sub-condenser 4. Become. As a result, the temperature of the air exchanged by the sub-condenser 4 becomes higher, so that a higher heating performance is exhibited and the so-called immediate warming property is also improved.

In this embodiment, in particular, the sub capacitor 4
Is controlled to supply or stop the power to the sheath heater 32 for heating the sub-evaporator 30 based on the air temperature Tsc immediately downstream of the compressor 6, thereby preventing the refrigerant refrigerant discharged from the compressor 6 from excessively rising. It is possible to do. Therefore, while maintaining the temperature of the air blown into the vehicle interior, it is possible to avoid a situation in which the frequency of the compressor 6 is controlled to be lowered due to an excessive rise in the refrigerant temperature discharged from the compressor 6, resulting in a decrease in the heating performance. Will be able to This makes it possible to exhibit excellent heating performance even at low outside temperatures.

Further, the control for supplying or stopping the electric power to the sheath heater 32 for heating the sub-evaporator 30 is performed based on the temperature Tw of the LLC 33 corresponding to the outside air temperature Ta. Excessive rise in the refrigerant temperature can be more reliably prevented, and even more excellent heating performance can be exhibited even at a low outside air temperature. Also, the required amount of heat is always generated,
The function of the sub-evaporator can be sufficiently exhibited while saving power.

FIG. 11 is a control flowchart of the suction port. As shown in the figure, the auto amplifier 50 determines the ratio between the outside air and the inside air of the air passing through the air inlet that takes in the air (outside air and / or inside air) to be sent into the vehicle cabin during the heating operation (YES in step S21). Then, normal heating suction port control is performed based on the temperature control lever (PTC) position and the like (step S22). However, if the calculated suction port target opening X is smaller than a predetermined ratio (preferably 50% here) selected from at least 30 to 60% in step S23 (YES in step S23), this suction is performed. Control for forcibly setting the mouth target opening X to the predetermined ratio is performed (step S24). Here, the target inlet opening X
Indicates the ratio of outside air to the whole air passing through the suction port. As described above, since at least the predetermined ratio or more of the air passing through the suction port was controlled to be outside air,
By taking in low-humidity outside air, window fogging can be reliably prevented.

FIG. 12 is a control flowchart of the temperature-sensitive cylinder heater. As shown in FIG.
In heating (YES in step S21), on / off determination of the temperature-sensitive cylinder heater 47 is performed based on the detection value of the heater surface temperature sensor 49 (step S32). The sheath heater control shown in FIG. 6 is performed, and the on / off determination is made when the pump 44 of the sheath heater unit 31 is operating or when the sheath heater 32 is on. You may.

In step S32, as shown in FIG. 13, when the surface temperature of the temperature-sensitive cylinder heater rises, when the heater surface temperature Th is at the reference temperature (for example, 60.degree. C.), the judgment is changed from the ON judgment to the OFF judgment. When the surface temperature of the heater is lowered, the heater surface temperature Th is set to a reference temperature (for example, 50 ° C.).
At this time, the judgment is made so that the judgment changes from the off judgment to the on judgment. The above reference temperature of the heater surface temperature Th can be set as appropriate.

Then, the on / off operation of the temperature-sensitive cylinder heater based on the detection value of the heater surface temperature sensor in step S34 is performed.
If the OFF determination is an ON determination (YES in step S33), the temperature-sensitive cylinder heater 47 is turned on (step S33).
34).

As described above, at the time of starting the heating operation in which the pump 44 of the sheathed heater unit 31 is operated, the temperature-sensitive cylinder heater 47 is turned on to forcibly open the throttled state of the expansion valve 8 and to release a large amount of refrigerant. Is returned to the compressor 6 to heat the interior of the vehicle, so that the immediate warming is further improved.

Further, as described above, the temperature-sensitive cylinder 4 of the expansion valve 8
When 6 is provided in the outlet pipe 18 of the sub-evaporator 30, the refrigerant flow rate is adjusted by the temperature of the refrigerant after being heated by the sub-evaporator 30, so that a larger amount of refrigerant circulates when the sub-evaporator 30 is activated. And the heating performance is further improved.

FIG. 14 is a sectional view showing an integrated expansion valve in which an expansion valve according to another embodiment of the present invention is incorporated in the valve.

The integral type expansion valve 80 is an expansion valve 8 shown in FIG.
In place of the symbol a. As shown in FIG. 14, in the first flow path 87 of the integrated expansion valve 80,
Bottleneck 8 for adiabatic expansion of high-pressure refrigerant from condenser
The opening of the valve seat 91 at one end of the bottleneck portion 89 is adjusted by the spherical valve element 90. The valve body 90 is interlocked with a diaphragm 94 of a temperature sensing section 93 installed outside the valve casing via a rod 92. The upper surface of the diaphragm 94 is in contact with a sealed gas that expands and contracts due to the temperature of the refrigerant passing through the second flow passage 88, and the lower surface thereof is in contact with the second flow passage 88.
The refrigerant passing inside is in contact. Therefore, when the temperature of the refrigerant in the second flow path 88 increases, the sealed gas expands, the diaphragm 94 is pushed from the upper surface, and the valve body 90 opens. A temperature-sensitive cylinder heater 86 is attached to the outer surface of the temperature-sensitive portion 93 of the integral expansion valve 80, and these are covered with a heat insulating material 48. The auto amplifier 50 controls the temperature-sensitive cylinder heater 86 to operate or stop based on the surface temperature of the temperature-sensitive cylinder heater 86 during the operation of the sheathed heater 32.

Even when such an integrated expansion valve 80 is used, it is possible to secure the flow rate of the refrigerant by heating the temperature sensing section 93 by the temperature sensing cylinder heater 86. Further, according to the integral type expansion valve 80, it is not necessary to use a long temperature sensing cylinder, and the assembling property is improved.

(Experimental Example 1) FIG.
FIG. 7 is a diagram showing an experimental result for determining a reference temperature KTsc when performing on / off control (hereinafter, referred to as TSC control) of a sheath heater 32 based on an air temperature Tsc immediately downstream of FIG. In FIG. 15, the above-mentioned reference temperature KTsc is set to 60 ° C. in the period t1 and the reference temperature KTsc is set in the period t2.
Assuming that sc is 55 ° C., the discharge refrigerant temperature Td of the compressor 6
And the foot outlet temperature TF. However, the heating of the thermosensitive tube is performed at an outside air temperature of -20 ° C. The blower for sending air into the duct 2 was set to Hi (high level) by applying a voltage of 10.5V.

According to the result of FIG. 15, in the former control,
There is a possibility that the refrigerant temperature Td discharged from the compressor 6 greatly exceeds 80 ° C., and a compressor frequency limit, which is a control for lowering the compressor frequency, is entered. on the other hand,
In the latter control, it can be seen that the foot outlet temperature TF within the predetermined temperature range can be ensured without the limitation of the compressor frequency.

(Experimental Example 2) FIG. 16 shows an outside air temperature of -10 ° C.
Operation and temperature control lever (PT)
It is a figure which shows the experimental result for evaluating the controllability in the change from C full hot position to an intermediate position of C). However, the above-described TSC control was performed while heating the temperature-sensitive cylinder. Further, as shown in the figure, the intake air temperature of the compressor 6 increases, and the refrigerant discharge temperature Td of the compressor 6 rises sharply only by the TSC control.
In period 3, the sheathed heater 32 depends on the temperature of the LLC 33.
ON / OFF control (hereinafter referred to as TW control)
Was added.

According to the results shown in FIG. 16, by setting the above-mentioned reference temperature KTW to 20 ° C. and adding TW control,
It can be seen that the foot outlet temperature TF within a predetermined temperature range can be ensured while keeping the discharge refrigerant temperature Td of the compressor 6 at about 80 ° C. or less.

(Experimental Example 3) FIG. 17 shows experimental results for evaluating the warm-up operation at an outside air temperature of 0 ° C. and the controllability of the change of the temperature control lever (PTC) from the full hot position to the intermediate position. FIG. However, the above-described TSC control was performed while heating the temperature-sensitive cylinder.

According to the results shown in FIG. 17, by setting the above-mentioned reference temperature KTW to 15 ° C. and adding TW control,
It can be seen that the foot outlet temperature TF within a predetermined temperature range can be ensured while keeping the discharge refrigerant temperature Td of the compressor 6 at about 80 ° C. or less.

(Experimental Example 4) FIG. 18 is a view showing an experimental result for evaluating a warm-up operation at an outside air temperature of 10 ° C. Here, the sheath heater 32 is turned off,
The temperature control lever (PTC) was set at the full hot position. However, heating of the temperature-sensitive cylinder was performed.

According to the results shown in FIG.
However, the foot outlet temperature TF exceeds 50 ° C. 10 minutes after the start of heating, and there is no problem in occupant feeling. At an outside air temperature of 10 ° C., it is not necessary to operate the sheathed heater 32. You can see that.

According to the experimental examples 2 to 4, the TW control supplies or stops power to the sheath heater 32 for heating the sub-evaporator 30 based on the temperature Tw of the LLC 33 corresponding to the outside air temperature Ta. It has been found that it is desirable to control.

(Experimental Example 5) Experimental results of the heating performance of the air conditioner for an electric vehicle including the above control are shown below.

[0069]

[Table 1]

As described above, at a low outside air temperature, an extremely good heating performance could be realized, the result of the defrost test was good, and the prevention of window fogging could be achieved.

The embodiments described above are not described to limit the present invention, and various modifications can be made by those skilled in the art within the technical concept of the present invention. For example, in the above-described embodiment, the sub-evaporator 30 is arranged outside the tank 34, and the LLC 33 heated by the sheath heater 32 in the tank 34 is guided to the sub-evaporator 30 by the circulation path 43 to perform heat exchange. However, the present invention is not limited to such a configuration, and both the sub-evaporator and the sheathed heater are housed in a tank in which LLC is sealed, and The present invention can also be applied to an electric vehicle air conditioner configured to connect a circulation path to the pump and circulate the LLC by a pump.

[0072]

As described above, according to the first aspect of the present invention, the outside evaporator heating means for heating the outside evaporator for heating the outside evaporator is operated or operated based on the air temperature on the downstream side of the inside cabin condenser. Since the stop control is performed, it is possible to prevent the temperature of the refrigerant discharged from the compressor from excessively rising. Therefore, while maintaining the temperature of the air blown into the vehicle interior, it is possible to avoid a situation in which the control of reducing the frequency of the compressor due to an excessive increase in the refrigerant discharge temperature of the compressor is performed, resulting in a decrease in the heating performance. Will be able to This makes it possible to exhibit excellent heating performance even at low outside temperatures.

According to the second aspect of the present invention, in addition to the effects of the first aspect, a sheath heater for heating the outside evaporator based on the temperature of the heat transfer medium according to the outside air temperature is provided. Control to supply or stop electric power is performed, so it is possible to more reliably prevent excessive rise in the temperature of the refrigerant discharged from the compressor, and it is possible to exhibit more excellent heating performance even at low outside temperatures Becomes In addition, a necessary amount of heat is always generated, so that the function of the evaporator outside the vehicle compartment can be sufficiently exhibited while saving power.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, window fogging can be reliably prevented by taking in low humidity outside air.

According to the invention set forth in claim 4, claims 1 to 5
In addition to the effect of the invention described in 3, the opening control member heating means is operated at the start of heating operation to forcibly open the throttled state of the expansion valve, and a large amount of refrigerant is returned to the compressor to heat the vehicle interior. As a result, immediate warming is further improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an air conditioner for an electric vehicle according to an embodiment of the present invention, in which (A) shows a flow of a refrigerant at the time of heating by a solid line, and (B) shows a flow of the refrigerant at the time of cooling. The flow is indicated by a solid line.

FIG. 2 is a detailed configuration diagram of a sub-evaporator and a sheathed heater unit shown in FIG.

FIG. 3 is a diagram showing the vicinity of a temperature-sensitive cylinder attached to an outlet pipe of a sub-evaporator.

FIG. 4 is a circuit diagram of heating control of a temperature sensing cylinder.

FIG. 5 is a block diagram showing an electrical configuration related to heating characteristics of the electric vehicle air conditioner. It is.

FIG. 6 is a control flowchart of a sheathed heater.

FIG. 7 is a diagram showing on / off control of a sheathed heater by a compressor frequency.

FIG. 8 is a diagram showing on / off control of a sheathed heater based on an air temperature immediately downstream of a sub-condenser.

FIG. 9 is a diagram showing a reference temperature for judging ON / OFF of a sheathed heater based on an LLC temperature according to an outside air temperature.

FIG. 10 is a diagram showing on / off control of a sheathed heater based on an LLC temperature according to an outside air temperature.

FIG. 11 is a control flowchart of a suction port.

FIG. 12 is a control flowchart of a temperature-sensitive cylinder heater.

FIG. 13 is a diagram showing on / off control of a temperature-sensitive cylinder heater based on a detection value of a heater surface temperature sensor.

FIG. 14 is a cross-sectional view showing an integrated expansion valve in which an expansion valve according to another embodiment of the present invention is incorporated in the valve.

FIG. 15 is a diagram showing an experimental result for determining a reference temperature when performing TSC control.

FIG. 16 is a diagram showing an experimental result for evaluating a warm-up operation at an outside air temperature of −10 ° C. and a controllability of a change of a temperature control lever from a full hot position to an intermediate position.

FIG. 17 is a diagram showing experimental results for evaluating a warm-up operation at an outside air temperature of 0 ° C. and a controllability of a change of a temperature control lever from a full hot position to an intermediate position.

FIG. 18 is a diagram showing experimental results for evaluating a warm-up operation at an outside air temperature of 10 ° C.

[Explanation of symbols]

3: Main evaporator (vehicle interior evaporator), 4: Sub condenser (vehicle interior condenser), 5: Main condenser (external condenser), 6: Compressor, 7: liquid tank, 8: expansion valve, 10: four-way valve (refrigerant) Flow path switching means), 11: bypass pipe, 18: outlet pipe, 30: sub-evaporator (evaporator outside vehicle compartment), 31: sheath heater unit (evaporator heating means outside vehicle compartment), 32: sheath heater (heating element), 33 ... LLC (heat transfer medium), 44: pump, 45: heat transfer medium temperature sensor, 46: temperature-sensitive cylinder (opening control member), 47: temperature-sensitive cylinder heater (opening control member heating means), 49: heater surface Temperature sensor (opening control member heating means temperature sensor), 50: auto amplifier (control means), 52: outside air temperature sensor, 53: air temperature Capacitors.

The continuation of the front page (72) The inventor Toshiharu Watanabe 5-24-15 Minamidai, Nakano-ku, Tokyo Calsonic Corporation

Claims (4)

[Claims] 1. A compressor constituting a refrigeration cycle
(6), outside condenser (5), inside condenser (4),
The expansion valve (8) and the vehicle interior evaporator (3) are connected in this order by refrigerant piping, and the compressor
A bypass pipe (11) for leading the refrigerant discharged from the (6) bypassing the external condenser (5) to the internal condenser (4), and a flow of the refrigerant discharged from the compressor (6); Refrigerant path switching means (10) provided in the refrigerant pipe downstream of the compressor (6) for switching the path,
The refrigerant discharged from the compressor (6) is introduced into the exterior condenser (5) by the refrigerant flow switching means (10) during the cooling operation, and is introduced by the refrigerant flow switching means (10) during the heating operation. In the air conditioner for an electric vehicle, which is directly introduced into the vehicle interior condenser (4) through a bypass pipe (11), a refrigerant outlet of the vehicle interior evaporator (3) and a refrigerant intake of the compressor (6) are provided. An external evaporator (30) disposed in the vehicle, an external evaporator heating means (31) for heating the external evaporator (30), and an air temperature sensor disposed downstream of the internal condenser (4). 53), and control means (50) for controlling the operation of the outside evaporator heating means (31) so as to operate or stop based on the air temperature detected by the air temperature sensor (53). To be The gas motor-vehicle air-conditioning system. 2. The outside evaporator heating means (31)
Is a heating element (3
2), and a heat transfer medium (33) for transmitting heat generated from the heating element (32) to the outside evaporator (30), wherein the electric vehicle air conditioner detects an outside air temperature. Further comprising a temperature sensor (52) and a heat transfer medium temperature sensor (45) for detecting the temperature of the heat transfer medium (33), wherein the control means controls the outside air temperature and the heat transfer medium (33). The air conditioner for an electric vehicle according to claim 1, wherein control is performed to supply or stop power to the heating element (32) based on the temperature. 3. The control means (50) determines that at least a predetermined ratio selected from at least 30 to 60% of air passing through an air inlet (19) for taking in air to be sent into a vehicle cabin during a heating operation is equal to outside air. The air conditioner for an electric vehicle according to claim 1, wherein the air conditioner is controlled so that the air conditioner is controlled. 4. The expansion valve (8) by sensing the temperature of an outlet pipe (18) from which refrigerant flows out of the vehicle interior evaporator (3) or the vehicle exterior evaporator (30).
An opening control member (46) for controlling the opening of the opening control member (46); an opening control member heating means (47) for heating the opening control member (46) to increase the opening of the expansion valve (8); An opening control member heating means temperature sensor (49) for detecting a temperature of the opening control member heating means (47), wherein the control means (50) heats the opening control member during a heating operation. The opening degree control member heating means based on the temperature of the means (47).
The air conditioner for an electric vehicle according to any one of claims 1 to 3, wherein the air conditioner is controlled to operate or stop.