JPH0688656A - Engine-driven heat pump type air conditioner - Google Patents

Abstract

PURPOSE:To make an effective use of exhaust heat from an engine upon cooling and heating operations. CONSTITUTION:A primary circuit 23 for circulating the refrigerant delivered from a compressor 22 driven by an engine 21 is provided therein with a four- way switching valve 24, an indoor side heat exchanger 25, an expansion valve 26, an outdoor side heat exchanger 27 and an accumulator 28 and a secondary circuit 37 is provided parallel to the primary circuit 23 between the accumulator 28 and the discharge side of the compressor 22. The secondary circuit 37 is provided therein with a liquid refrigerant pump 38 for force feeding the liquid refrigerant supplied from the accumulator 28 and a refrigerant heater 39 for heating and vaporizing this liquid refrigerant with the exhaust heat from the engine 21. The liquid refrigerant pump 38 is operated upon heating and cooling operations to use the exhaust heat from the engine 21 as an auxiliary heating source during the heating period and as an auxiliary operating means for the compressor 22 for the cooling operating period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine-driven heat pump for cooling and heating by switching the circulation direction of a refrigerant in a main circuit having an indoor heat exchanger and an outdoor heat exchanger with a switching valve. Type air conditioner.

[0002]

2. Description of the Related Art A conventional engine-driven heat pump type air conditioner is installed in a main circuit for circulating a refrigerant discharged from a compressor driven by an engine, as disclosed in, for example, Japanese Patent Laid-Open No. 61-6558. , 4-way switching valve,
An indoor heat exchanger, a receiver, an expansion valve, and an outdoor heat exchanger are provided, and cooling / heating is performed by switching the circulation direction of the refrigerant in the main circuit with the four-way switching valve. This one bypasses a part of the liquid refrigerant in the receiver to the auxiliary circuit during heating so that the exhaust heat of the engine can be used as a heating auxiliary heat source during heating, and sends it to the refrigerant heater by the liquid pump, The refrigerant heater heats the refrigerant by exhaust heat of the engine and transports it to the indoor heat exchanger. On the other hand, during cooling, the liquid pump is maintained in the off state so that the refrigerant is circulated only in the main circuit.

[0003]

According to the above conventional structure, the exhaust heat of the engine can be effectively used during heating, but the exhaust heat of the engine cannot be used at all during cooling, and the heat is radiated to the atmosphere through the radiator. I have to. For this reason, the energy efficiency during cooling is lower than that during heating, resulting in poor fuel efficiency, and a large radiator is required, resulting in an increase in the installation space.

The present invention has been made in consideration of the above circumstances, and its purpose is to effectively use the exhaust heat of the engine during cooling, as in the case of heating, and to improve the cooling capacity and the fuel consumption as well as the radiator. An object of the present invention is to provide an engine-driven heat pump type air conditioner that can be downsized or eliminated.

[0005]

In order to achieve the above object, an engine-driven heat pump type air conditioner of the present invention comprises:
A switching valve, an indoor heat exchanger, an expansion valve, an outdoor heat exchanger, and a liquid reservoir are provided in the main circuit that circulates the refrigerant discharged from the compressor driven by the engine. In the one in which cooling and heating are performed by switching the circulation direction by the switching valve, a sub circuit is provided in parallel with the main circuit between the liquid reservoir and the discharge side of the compressor, and in this sub circuit. A liquid refrigerant pumping means for pumping the liquid refrigerant supplied from the liquid reservoir, and a refrigerant heater for heating and evaporating the liquid refrigerant pumped by the liquid refrigerant pumping means by the exhaust heat of the engine. The liquid refrigerant pumping means is configured to operate during cooling and heating.

[0006]

According to the above construction, during cooling, as in heating, the liquid refrigerant pumping means is operated to bypass a part of the liquid refrigerant in the liquid reservoir to the sub-circuit and pump it to the refrigerant heater. .
Then, the liquid refrigerant is heated by the exhaust heat of the engine by this refrigerant heater to be vaporized (gasified) and returned to the discharge side of the compressor in the main circuit.

During heating, the exhaust heat of the engine received by the refrigerant heater of the sub circuit is transported to the indoor heat exchanger via the switching valve in the main circuit. As a result, the exhaust heat of the engine is used as a heating auxiliary heat source to enhance the heating capacity.

On the other hand, at the time of cooling, the jet pressure of the gas refrigerant returned to the discharge side of the compressor in the main circuit through the sub circuit as described above is auxiliary to the compressor for pumping the refrigerant circulating in the main circuit. It plays a role and promotes the circulation of the refrigerant in the main circuit to enhance the cooling capacity. Therefore, even during cooling, the exhaust heat of the engine is effectively used as in the case of heating.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. The engine-driven heat pump type air conditioner of the first embodiment is mounted on, for example, a vehicle and driven by an engine 21.
Reference numeral 1 denotes an air-conditioning engine provided separately from a vehicle running engine (not shown).

In the main circuit 23 for circulating the refrigerant discharged from the discharge port 22a of the compressor 22 driven by the engine 21, a four-way switching valve 24, an indoor heat exchanger 25, an expansion valve 26, an outdoor heat An exchanger 27 and an accumulator 28 that is a liquid reservoir are provided. During heating, switch the four-way switching valve 24 to the position shown by the solid line,
The refrigerant discharged from the discharge port 22a of the compressor 22 is supplied with the four-way switching valve 24 → the indoor heat exchanger 25 → the expansion valve 2
6-> outdoor heat exchanger 27-> four-way switching valve 24-> accumulator 28-> the suction port 22b of the compressor 22 is circulated. On the other hand, during cooling, the four-way switching valve 24 is switched to the position shown by the dotted line, and the discharge port 22a of the compressor 22 → the four-way switching valve 24 → the outdoor heat exchanger 27 →
Expansion valve 26 → indoor heat exchanger 25 → four-way switching valve 24 → accumulator 28 → suction port 2 of compressor 22
The refrigerant is circulated in the path 2b. The opening degree of the expansion valve 26 is adjusted by the motor 67.

Further, the discharge port 22 of the compressor 22
On the a side, a pressure switch 29 for detecting the pressure of the refrigerant,
A coolant temperature sensor 30 that detects the coolant temperature is provided. Further, refrigerant temperature sensors 31 to 34 for detecting the refrigerant temperature are provided on the indoor heat exchanger 25, both sides of the expansion valve 26 and the outdoor heat exchanger 27, respectively. An indoor unit fan 35 that blows the air that has exchanged heat with the indoor heat exchanger 25 into the passenger compartment is provided near the indoor heat exchanger 25, and an outdoor heat exchanger is provided near the outdoor heat exchanger 27. Exchanger 2
An outdoor unit fan 36 that promotes the heat radiation of 7 is provided.

On the other hand, a sub circuit 37 is provided in parallel with the main circuit 23 between the accumulator 28 and the discharge port 22a side of the compressor 22. In the sub-circuit 37, a liquid refrigerant pump 38 serving as a liquid refrigerant pumping means for pumping the liquid refrigerant supplied from the accumulator 28, and a liquid refrigerant pumped by the liquid refrigerant pump 38 are supplied to the engine 2
A refrigerant heater 39 that heats and evaporates by the exhaust heat of 1 is provided. The liquid refrigerant pump 38 is driven by a motor 40.

The refrigerant heater 39 has a sub-circuit 3 at the center thereof.
7 penetrates, and high-temperature engine cooling water flows from the engine cooling water circuit 41 around it. In the engine cooling water circuit 41, the cooling water air separator 4
2, an exhaust heat exchanger 44 for exchanging heat with the exhaust of the cooling water pump 43 and the engine 21 is provided. Further, the engine cooling water circuit 41 is provided with a water temperature sensor 66 for detecting the temperature of the engine cooling water flowing into the refrigerant heater 39. A reserve tank 45 is connected to the cooling water air separator 42.

The rotational speed of the engine 21 (rotational speed of the compressor 22) is controlled by varying the throttle opening with a throttle opening control motor 46.

Next, the structure of the electric circuit will be described with reference to FIG. For the power source 47, the motor 48 of the indoor unit fan 35, the motor 49 of the outdoor unit fan 36, and the four-way switching valve 2
4 are provided in parallel. Each motor 48, 49 has
High speed relay contacts 50a, 51a, medium speed relay contact 52
a, 53a, low speed relay contacts 54a, 55a and ultra low speed relay contacts 56a, 57a. A normally open relay contact 58a is connected in series to the four-way switching valve 24.

On the other hand, each input terminal of the control circuit 59 for controlling the heating / cooling is connected to the cooling switch 60, the heating switch 61,
The pressure switch 29, the room temperature setting switch 63, the room temperature sensor 64, the outside air temperature sensor 65, the water temperature sensor 66, and the refrigerant temperature sensors 30 to 34 are connected. In addition, the control circuit 5
The motor 40 of the liquid refrigerant pump 38,
Motor 67 of expansion valve 26, throttle opening control motor 4
6. The relay coils 50b to 58b for driving the relay contacts 50a to 58a described above are connected.

The control circuit 59 is composed of, for example, a microcomputer. When either the cooling switch 60 or the heating switch 61 is turned on, the control circuit 59 starts the processing of the cooling / heating control program shown in FIGS. The cooling / heating operation is controlled as follows.

First, the room temperature T of the room temperature setting switch 63 is set.
s, room temperature Ti detected by room temperature sensor 64, outside air temperature sensor 65
Of the detected outside temperature To, the engine temperature Tw of the engine detected by the water temperature sensor 66, the pressure PH detected by the pressure switch 29, the refrigerant temperatures TD, THEI, TSCH, TSCC detected by the refrigerant temperature sensors 30 to 34.
Read THEO (step S1). Next, it is determined whether it is cooling or heating (step S2), and if it is heating, the process proceeds to step S3, and the four-way switching valve 24 is switched to the position shown by the solid line in FIG. 1 to operate in the heating cycle.

In this heating cycle, the compressor 22
Of the refrigerant discharged from the discharge port 22a of the four-way switching valve 24 → the indoor heat exchanger 25 → the expansion valve 26 → the outdoor heat exchanger 27 → the four-way switching valve 24 → the accumulator 28 → the suction port 22b of the compressor 22 Circulate with.
As a result, the high temperature gas refrigerant discharged from the discharge port 22a of the compressor 22 is radiated by the indoor heat exchanger 25 to heat the passenger compartment.

Further, the liquid refrigerant pump 38 is driven by the motor 40.
Is operated to bypass a part of the liquid refrigerant in the accumulator 28 by the sub-circuit 37 and pressure-feed it to the refrigerant heater 39. This liquid refrigerant passes through the refrigerant heater 39,
It absorbs the heat of engine cooling water and evaporates to become a gas refrigerant. The gas refrigerant returns from the sub circuit 37 to the discharge side of the compressor 22 in the main circuit 23, merges with the refrigerant discharged from the compressor 22, and flows to the indoor heat exchanger 25 via the four-way switching valve 24. . Thus, the exhaust heat of the engine 21 received by the refrigerant heater 39 is transported to the indoor heat exchanger 25 and used as a heating auxiliary heat source to enhance the heating capacity.

During this heating, in step S4, the heating capacity mode is determined based on the set room temperature Ts, the detected room temperature Ti and the detected outside air temperature To, and the throttle opening control motor 4 is operated.
6, motor 48 of indoor unit fan 35 and outdoor unit fan 3
The rotation speed of the motor 49 of No. 6 is controlled. Next, the engine water temperature Tw detected by the water temperature sensor 66 is “appropriate”.
It is determined which of "high" and "low" (step S5). If "low", the process proceeds to step S6, the motor 40 of the liquid refrigerant pump 38 is decelerated, and the liquid of the sub circuit 37 is discharged. The refrigerant flow rate G2 is reduced by a certain amount. As a result, the amount of heat absorbed from the engine cooling water by the refrigerant heater 39 of the sub circuit 37 is reduced, and the engine water temperature Tw is quickly raised to an appropriate level. This is because if the engine water temperature Tw is lower than the proper value, the fuel efficiency of the engine 21 deteriorates.

On the other hand, in step S5, the engine water temperature Tw
Is determined to be "high", the process proceeds to step S7, the motor 40 of the liquid refrigerant pump 38 is sped up, and the liquid refrigerant flow rate G2 of the sub circuit 37 is increased by a fixed amount. As a result, the amount of heat absorbed from the engine cooling water by the refrigerant heater 39 of the sub circuit 37 is increased, and the engine water temperature Tw is promptly reduced to an appropriate level. This is because even if the engine water temperature Tw is higher than the proper value, the fuel efficiency of the engine 21 deteriorates.

Further, in step S5, the engine water temperature Tw
Is determined to be “appropriate”, the process proceeds to step S8, the rotation number of the motor 40 of the liquid refrigerant pump 38 is not changed, and the liquid refrigerant flow rate G2 of the sub circuit 37 is continuously maintained at the same level.

When any one of the steps S6 to S8 described above is completed, the process proceeds to step S9, and whether the refrigerant pressure PH on the discharge side of the compressor 22 detected by the pressure switch 29 is "high" or "low". To judge. When the refrigerant pressure PH is "high", the heating capacity is sufficiently exerted, so in order to improve the fuel consumption, the routine proceeds to step S10, where the rotational speed of the throttle opening control motor 46 is decelerated by one rank. Then, the rotation speed of the engine 21 is reduced to reduce the refrigerant circulation flow rate of the main circuit 23, the rotation speed of the motor 49 of the outdoor unit fan 36 is reduced by one rank, and the heat radiation amount of the outdoor heat exchanger 27 is reduced. To reduce. However, the rotation speed of the motor 48 of the indoor unit fan 35 is not reduced and the same level of hot air is continuously maintained. This step S1
When the process of 0 is completed, the process proceeds to step S11.

On the other hand, when the refrigerant pressure PH is "low",
Immediately, the process proceeds to step S11, and the degree of superheat (TD-THEI) of the refrigerant discharged from the compressor 22 is "appropriate".
It is determined whether it corresponds to “large” or “small”. Here, TD is the discharge refrigerant temperature detected by the refrigerant temperature sensor 30 installed on the discharge side of the compressor 22, and THEI is detected by the refrigerant temperature sensor 31 installed on the indoor heat exchanger 25. The discharge refrigerant superheat degree (TD-THEI) is obtained by calculating the temperature difference between the discharge refrigerant temperature TD and the condensation temperature THEI.

The opening degree of the expansion valve 26 is controlled in steps S12 to S15 in accordance with the degree of discharge refrigerant superheat (TD-THEI). The purpose and principle of this control are as follows.

That is, since the liquid refrigerant in the accumulator 28 is always taken out to the sub circuit 37, it is necessary to stably secure the amount of liquid refrigerant in the accumulator 28, and further, the main circuit 23 has an efficient cooling / heating capacity. Therefore, it is necessary to control the degree of supercooling of the refrigerant flowing into the expansion valve 26 so that the above effect can be exhibited.

In general, in a refrigeration cycle using the accumulator 28, when the amount of liquid refrigerant in the accumulator 28 decreases, the gas refrigerant discharged from the compressor 22 exhibits a change characteristic in which the degree of superheat increases. Further, when the opening degree of the expansion valve 26 is increased, the degree of supercooling of the refrigerant flowing into the expansion valve 26 decreases, and the amount of liquid refrigerant in the accumulator 28 increases, which is a change characteristic. Paying attention to these two change characteristics, the refrigerant superheat degree (T
D-THEI) is detected and the opening degree of the expansion valve 26 is feedback-controlled.

Specifically, in step S11, the detected discharge refrigerant superheat degree (TD-THEI) is "appropriate" or "large".
It is determined which of "small" is applicable, and if "large", the process proceeds to step S12, the opening degree of the expansion valve 26 is opened by a certain amount, and the discharge refrigerant superheat degree (TD-THEI) is reduced. . On the contrary, detected discharge refrigerant superheat (TD-THEI)
Is "small", the process proceeds to step S13, the opening degree of the expansion valve 26 is closed by a certain amount, and the discharge refrigerant superheat degree (TD-THE).
I) increase. Such discharge refrigerant superheat degree (TD-TH
The amount of liquid refrigerant in the accumulator 28 is properly controlled by repeatedly executing the control of (EI) every predetermined time (step S16).

On the other hand, the detected discharge refrigerant superheat degree (TD-T
If HEI) is "appropriate", the process proceeds to step S14, and the degree of supercooling of the refrigerant flowing into the expansion valve 26 (THEI-T
SCH). Here, THEI is the condensation temperature detected by the refrigerant temperature sensor 31 installed in the indoor heat exchanger 25, and TSCH is the refrigerant temperature installed on the refrigerant inflow side (left side) of the expansion valve 26 during heating. It is the refrigerant temperature detected by the sensor 32. By calculating the temperature difference between the condensation temperature THEI and the refrigerant temperature TSCH, the degree of supercooling (T
HEI-TSCH). This degree of supercooling (THEI-TSC
The control principle of (H) utilizes the change characteristic that the degree of supercooling (THEI-TSCH) of the expansion valve 26 increases when the opening degree of the expansion valve 26 is reduced, and this degree of supercooling (THEI-TSCH) is detected. The opening degree of the expansion valve 26 is feedback-controlled.

Specifically, when the amount of liquid refrigerant in the accumulator 28 becomes appropriate, the discharge refrigerant superheat degree (TD-THEI).
) Becomes "appropriate", the process proceeds to step S14, and it is determined whether the detected supercooling degree (THEI-TSCH) of the expansion valve 26 is "appropriate", "large" or "small".
If "large", the process proceeds to step S12, and the expansion valve 2
6 is opened by a certain amount and the degree of supercooling of the expansion valve 26 (THEI
-TSCH). On the contrary, the detected supercooling degree (T
HEI-TSCH) is "small", the process proceeds to step S13, the opening degree of the expansion valve 26 is closed by a certain amount, and the degree of supercooling (THEI-TSCH) of the expansion valve 26 is increased. If the detected degree of supercooling (THEI-TSCH) is "appropriate",
After shifting to step S15, the opening degree of the expansion valve 26 is not changed and is maintained in that state. By repeating such supercooling degree control of the expansion valve 26 every predetermined time (step S16), the subcooling degree of the expansion valve 26 is appropriately controlled.

The change in the state of the refrigerant in the heating cycle described above is shown on the Mollier diagram of FIG. In this Mollier diagram, the stroke of g → d is the compressor 22
Is the adiabatic compression stroke of the gas refrigerant, and the discharge refrigerant flow rate is G1. The process of d → a is the indoor heat exchanger 25.
Is a condensation process (heat dissipation process) of the high temperature gas refrigerant, and the flow rate of the refrigerant (G1 + G2) flowing into the indoor heat exchanger 25 is
) Is the total of the discharge refrigerant flow rate G1 of the compressor 22 and the refrigerant flow rate G2 of the sub circuit 37. The process of a → f is
The adiabatic expansion stroke in the expansion valve 26, and the stroke f → m ′ is the evaporation stroke of the liquid refrigerant by the outdoor heat exchanger 25. Here, m ′ represents the state of the gas component of the refrigerant in the accumulator 28, and this gas component returns to the suction side g of the compressor 22 while being slightly decompressed. The cycle of g → d → a → f → m ′ → g explained above is the main circuit 2
3 is a state change of the refrigerant circulating in 3.

In parallel with the circulation of the refrigerant in the main circuit 23, the accumulator 2 is operated in the sub circuit 37 (m '→ m → k → d).
The liquid refrigerant m condensed in 8 is sucked into the sub-circuit 37 side, pressurized to k by the liquid refrigerant pump 38, heated and evaporated by the refrigerant heater 39, and returned to the discharge side d of the main circuit 23. The refrigerant discharged from the compressor 22 merges with the refrigerant, flows to the indoor heat exchanger 25 side, and is condensed in the process of d → a.

On the other hand, during cooling, step S shown in FIG.
17, the four-way switching valve 24 is switched to the position shown by the dotted line in FIG. 1 to operate in the cooling cycle.

In this cooling cycle, the compressor 22
Of the refrigerant discharged from the discharge port 22a of the four-way switching valve 24 → the outdoor heat exchanger 27 → the expansion valve 26 → the indoor heat exchanger 25 → the four-way switching valve 24 → the accumulator 28 → the suction port 22b of the compressor 22 Circulate with.
As a result, the liquid refrigerant condensed in the outdoor heat exchanger 27 is evaporated in the indoor heat exchanger 25 to cool the vehicle interior.

Also during this cooling, as in the case of heating, the liquid refrigerant pump 38 is operated by the motor 40 to bypass a part of the liquid refrigerant in the accumulator 28 to the sub-circuit 37 and pressure-feed it to the refrigerant heater 39. In the process of passing through the refrigerant heater 39, this liquid refrigerant absorbs heat of the engine cooling water and evaporates to become a gas refrigerant. This gas refrigerant is used in the sub circuit 3
7 returns to the discharge side of the compressor 22 in the main circuit 23 and joins the refrigerant discharged from the compressor 22.
In this way, the jet pressure of the gas refrigerant returned from the sub-circuit 37 to the discharge side of the compressor 22 in the main circuit 23 causes the compressor 22 to pump the refrigerant circulating in the main circuit 23.
To promote the circulation of the refrigerant in the main circuit 23 and enhance the cooling capacity. Therefore, even during cooling, the exhaust heat of the engine 21 is effectively used as in heating.

During this cooling, in step S18, the cooling capacity mode is determined based on the set room temperature Ts, the detected room temperature Ti, and the detected outside air temperature To, and the throttle opening control motor 46,
The rotation speeds of the motor 48 of the indoor unit fan 35 and the motor 49 of the outdoor unit fan 36 are controlled. Next, the water temperature sensor 6
The engine water temperature Tw detected by 6 is “appropriate” “high”
It is determined which of "low" is applicable (step S1).
9) If "low", the process proceeds to step S20, the motor 40 of the liquid refrigerant pump 38 is decelerated, and the liquid refrigerant flow rate G2 of the sub circuit 37 is reduced by a certain amount. As a result, the amount of heat absorbed from the engine cooling water by the refrigerant heater 39 of the sub circuit 37 is reduced, and the engine water temperature Tw is quickly raised to an appropriate level.

On the other hand, in step S19, the engine water temperature T
If w is determined to be “high”, the process proceeds to step S21,
The speed of the motor 40 of the liquid refrigerant pump 38 is increased so that the sub circuit 37
The liquid refrigerant flow rate G2 is increased by a certain amount. As a result, the amount of heat absorbed from the engine cooling water by the refrigerant heater 39 of the sub circuit 37 is increased, and the engine water temperature Tw is promptly reduced to an appropriate level.

In step S19, the engine water temperature T
When w is determined to be "appropriate", the process proceeds to step S22, the rotation number of the motor 40 of the liquid refrigerant pump 38 is not changed, and the liquid refrigerant flow rate G2 of the sub circuit 37 is continuously maintained at the same level.

When any one of the steps S20 to S22 described above is completed, the process proceeds to step S23, and whether the refrigerant pressure PH on the discharge side of the compressor 22 detected by the pressure switch 29 is "high" or "low". To judge. When the refrigerant pressure PH is "high", the process proceeds to step S24 to improve the cooling capacity, and the outdoor unit fan 36
The number of rotations of the motor 49 is increased by one rank to increase the heat radiation amount of the outdoor heat exchanger 27. After this, step S2
Go to 5.

On the other hand, when the refrigerant pressure PH is "low",
Immediately, the process proceeds to step S25, and the degree of superheat (TD-THEO) of the refrigerant discharged from the compressor 22 is "appropriate".
It is determined whether it corresponds to “large” or “small”. Here, TD is the discharge refrigerant temperature detected by the refrigerant temperature sensor 30 installed on the discharge side of the compressor 22, and THEO is detected by the refrigerant temperature sensor 34 installed on the outdoor heat exchanger 27. The discharge refrigerant superheat degree (TD-THEO) is obtained by calculating the temperature difference between the discharge refrigerant temperature TD and the condensation temperature THEO.

If it is determined in step S25 that the detected degree of discharge refrigerant superheat (TD-THEO) is "large", the process proceeds to step S26, in which the expansion valve 26 is opened by a certain amount to discharge refrigerant superheat. Decrease the degree (TD-THEO). On the contrary, when the detected discharge refrigerant superheat degree (TD-THEO) is "small", the process proceeds to step S27 and the expansion valve 2
The opening of 6 is closed by a certain amount, and the discharge refrigerant superheat degree (TD-THE
O) increase. Such discharge refrigerant superheat degree (TD -T
By repeatedly executing the control of (HEO) every predetermined time (step S30), the amount of liquid refrigerant in the accumulator 28 is appropriately controlled.

On the other hand, when the amount of the liquid refrigerant in the accumulator 28 becomes appropriate, the discharge refrigerant superheat degree (TD-THEO) becomes "appropriate", and the routine proceeds to step S28, where the detected supercooling degree of the expansion valve 26 ( THEO-TSCC) is "appropriate"
It is determined whether it corresponds to “large” or “small”. Here, THEO is a condensation temperature detected by the refrigerant temperature sensor 34 installed in the outdoor heat exchanger 27, and TSCC is
It is the refrigerant temperature detected by the refrigerant temperature sensor 33 installed on the refrigerant inflow side of the expansion valve 26 during cooling. By calculating the temperature difference between the condensation temperature THEO and the refrigerant temperature TSCC, the degree of supercooling (THEO − TSCC).

In step S28, the detected expansion valve 2
When it is determined that the degree of supercooling (THEO-TSCC) of 6 is "large", the process proceeds to step S26, the opening degree of the expansion valve 26 is opened by a certain amount, and the degree of supercooling (THEO-TSCCC) of the expansion valve 26 is increased. )
Lower. On the contrary, the detected degree of supercooling (THEO-TSC
If C) is "small", the process proceeds to step S27, the opening degree of the expansion valve 26 is closed by a certain amount, and the degree of supercooling (THEO-TSCC) of the expansion valve 26 is increased. If the detected degree of supercooling (THEO-TSCC) is "appropriate", the process proceeds to step S29 and the expansion valve 26 is held in that state without being changed. By repeating such supercooling degree control of the expansion valve 26 every predetermined time (step S30), the supercooling degree of the expansion valve 26 is appropriately controlled.

According to the first embodiment described above,
In any case of heating, the liquid refrigerant pump 38 is operated to remove a part of the liquid refrigerant in the accumulator 28 from the sub-circuit 3
7 and bypasses to the refrigerant heater 39. Then, the refrigerant heater 39 heats the liquid refrigerant by the exhaust heat of the engine 21 to evaporate (gasify) it and return it to the discharge side of the compressor 22 in the main circuit 23. Thus, during heating, the exhaust heat of the engine 21 received by the refrigerant heater 39 is transported to the indoor heat exchanger 25 via the four-way switching valve 24 in the main circuit 23 and used as a heating auxiliary heat source. The heating capacity can be increased.

On the other hand, during cooling, the jet pressure of the gas refrigerant returned to the discharge side of the compressor 22 in the main circuit 23 through the sub circuit 37 as described above pumps the refrigerant circulating in the main circuit 23. It plays an auxiliary role of the compressor 22 and promotes the circulation of the refrigerant in the main circuit 23 to improve the refrigeration cycle efficiency. Therefore, even during cooling
As in the case of heating, the exhaust heat of the engine can be effectively used, the cooling capacity can be improved and the fuel consumption can be improved.

Moreover, in both cases of cooling and heating,
Since the heat of the engine 21 can be absorbed by the refrigerant heater 39, the radiator for radiating the heat of the engine 1 can be downsized or eliminated. Normally, the radiator is arranged adjacent to the outdoor heat exchanger 27, and therefore, due to the miniaturization and elimination of the radiator, only the space corresponding to
It is possible to increase the capacity of the outdoor heat exchanger 27, which leads to improvement in cooling and heating capacity. Further, if the radiator can be eliminated, there is an advantage that the piping of the engine cooling water circuit 41 can be simplified.

In the first embodiment described above, the sub circuit 37 is used.
Although the liquid refrigerant pump 38 is adopted as the liquid refrigerant pumping means for pumping the liquid refrigerant, the liquid refrigerant pumping means 71 is constituted by means other than the pump as in the second embodiment of the present invention shown in FIG. 6, for example. May be.

The liquid refrigerant pumping means 71 of the second embodiment is
A first check valve 72, a liquid refrigerant reservoir 73, and a second check valve 74 are sequentially connected in the sub circuit 37, and the liquid refrigerant reservoir 73 is connected to a suction side of the compressor 22 via a pressure reducing electromagnetic valve 75. The pressure reducing circuit 76 connected to the
The discharge side of 2 is connected to the liquid refrigerant reservoir 7 via the second solenoid valve 77.
3 is provided with a pressurizing circuit 78. Further, a pressure circuit 78 is provided on the discharge side of the compressor 22 in the main circuit 23.
Located downstream of the branch point 79 of the gas refrigerant resistor 8
0 is set.

The liquid refrigerant is sent under pressure by the liquid refrigerant pumping means 71 having such a structure as described above.
5 and 5 are alternately opened and closed. That is, when the pressurizing solenoid valve 77 is opened, a part of the high-pressure gas refrigerant discharged from the compressor 22 flows into the liquid refrigerant reservoir 73 via the pressurizing circuit 78. As a result, the liquid refrigerant reservoir 7
The pressure in 3 rises, and the liquid refrigerant in the liquid refrigerant reservoir 73 passes through the second check valve 74 and is pumped to the refrigerant heater 39 side.

In this way, after the liquid refrigerant in the liquid refrigerant reservoir 73 is pressure-fed to the refrigerant heater 39 side, the pressurizing solenoid valve 77 is closed and the depressurizing solenoid valve 75 is opened. The high pressure gas refrigerant in the liquid refrigerant reservoir 73 is sucked into the compressor 22 via the pressure reducing circuit 76. As a result, the pressure in the liquid refrigerant reservoir 73 drops sharply, and the pressure in the liquid refrigerant reservoir 73 becomes lower than the pressure in the accumulator 28.
Due to the pressure difference, the liquid refrigerant in the accumulator 28 passes through the first check valve 72 and is sucked into the liquid refrigerant reservoir 73. Thereafter, when the liquid refrigerant reservoir 73 is almost filled with the liquid refrigerant, the pressure reducing electromagnetic valve 75 is closed and the pressurizing electromagnetic valve 77 is closed. The liquid refrigerant in the reservoir 73 is pumped.

On the other hand, in the third embodiment of the present invention shown in FIG. 7, the rotary liquid refrigerant pump 81 is employed as the liquid refrigerant pumping means in the sub circuit 37. This rotary liquid refrigerant pump 8
In No. 1, a three-bladed rotor 83 is provided in a main body casing 82, and the main body casing 82 is partitioned into three chambers A, B, and C by the rotor 83. This body casing 8
An inflow port 84 for inflowing the liquid refrigerant from the accumulator 28 is formed in the upper part of 2, and a discharge port 85 for discharging the liquid refrigerant to the refrigerant heater 39 side is formed in the lower part of the main body casing 82. Further, in the main body casing 82,
A pressurizing port 87 is formed at a position rotated by 135 ° in the clockwise direction from the inflow port 84, and the pressurizing port 87 is connected to the discharge side of the compressor 22 via a pressurizing circuit 86. Further, a pressure reducing port 89 is formed at a position rotated by 135 ° in the clockwise direction from the discharge port 85, and this pressure reducing port 89 is connected to the suction side of the compressor 22 via a pressure reducing circuit 88.

This rotary liquid refrigerant pump 81 has a pressurizing port 8
The chamber A communicating with 7 is pressurized to a high pressure state by the discharge pressure of the compressor 22, and the chamber B communicating with the pressure reducing port 89 is reduced to a low pressure state by the suction pressure of the compressor 22.
By rotating the rotor 83 at a low speed by using the pressure difference between the chambers A and B as a power source, the liquid refrigerant is sucked from the suction port 84 and discharged from the discharge port 85.

Further, in the fourth embodiment of the present invention shown in FIG. 8, the reciprocating type liquid refrigerant pressure feeder 91 is adopted as the liquid refrigerant pressure feeding means in the sub circuit 37. This reciprocating liquid refrigerant pump 91 has a hollow piston 93 inside a main body cylinder 92.
The hollow piston 93 is stored slidably to the left and right.
The inner space is divided into two chambers D and E by a partition wall 94. Corresponding to these two chambers D and E, two inflow ports 95 and 96 for allowing the liquid refrigerant to flow from the accumulator 28 are formed in the upper surface of the main body cylinder 92, and the lower surface of the main body cylinder 92 is heated by the refrigerant. One discharge port 97 for discharging the liquid refrigerant is formed on the container 39 side. Correspondingly, two inlets 98, 99 are formed on the upper surface of each chamber D, E of the hollow piston 93, and two discharge ports 100, 101 are also formed on the bottom surface. Further, the right chamber D of the hollow piston 93 is communicated with the discharge side of the compressor 22 via the communication hole 102 at the upper end of the right side surface of the hollow piston 93, the port 103 on the right side surface of the main body cylinder 92, and the four-way switching valve 104. . On the other hand, the left chamber E of the hollow piston 93
Is communicated with the suction side of the compressor 22 via a communication hole 105 on the upper left side of the hollow piston 93, a port 106 on the left side of the main body cylinder 92, and a four-way switching valve 104.

In this fourth embodiment, the hollow piston 93 is reciprocated left and right by alternately switching the four-way switching valve 104 between the solid line position and the dotted line position shown in FIG.
The liquid refrigerant is pressure-fed to the refrigerant heater 39 side. That is, when the four-way switching valve 104 is switched to the solid line position shown in FIG. 8, the right side inside the main body cylinder 92 is the compressor 2
It is pressurized to a high pressure state by the discharge pressure of 2, and the left side inside the main body cylinder 92 is reduced to a low pressure state by the suction pressure of the compressor 22. As a result, the hollow piston 93 slides to the left, the inlet 99 of the left chamber E in the hollow piston 93 is aligned with the inlet 96 on the left side of the main body cylinder 92, and the liquid enters the left chamber E of the hollow piston 93. The refrigerant flows in and is stored (the discharge port 101 on the bottom surface of the left chamber E is closed by the bottom surface of the main body cylinder 92). The right-side inlet 95 of the main body cylinder 92 has a hollow piston 93.
Closed in the right chamber D of the hollow piston 93.
The internal pressure is increased to a high pressure by the discharge pressure of the compressor 22, and the discharge port 100 on the bottom surface of the right chamber D is discharged.
Is in a state of being aligned with the discharge port 97 of the main body cylinder 92, and the liquid refrigerant in the right chamber D is pumped to the refrigerant heater 39 side.

In this way, after the liquid refrigerant in the right chamber D is almost pressure-fed to the refrigerant heater 39 side, the four-way switching valve 104 is switched to the dotted line position shown in FIG. As a result, the left side inside the main body cylinder 92 becomes high pressure, the hollow piston 93 slides to the right, the liquid refrigerant in the left chamber E is pumped to the refrigerant heater 39 side, and the liquid refrigerant in the right chamber D flows. Refrigerant flows in and is stored. After that, the hollow piston 93 is reciprocated left and right by repeating the switching operation of the four-way switching valve 104 described above, and the liquid refrigerant is pressure-fed to the refrigerant heater 39 side.

The first to fourth embodiments described above are
In both cases, the accumulator 28 is used as a liquid reservoir for supplying the liquid refrigerant to the sub circuit 37 side. However, as in the fifth embodiment of the present invention shown in FIG. 9, the liquid refrigerant is supplied to the sub circuit 37 side. The receiver 110 may be used as the liquid reservoir to be supplied. In this fifth embodiment, four check valves 111 to 114 are bridge-connected between the indoor heat exchanger 25 and the outdoor heat exchanger 27, and the receiver 110 and the expansion valve 26 are connected in the bridge circuit. Is provided. In this case, during heating, the liquid refrigerant supplied from the indoor heat exchanger 25 is the check valve 111 → the receiver 110 → the expansion valve 26 → the check valve 1
12 → outdoor heat exchanger 27, while the liquid refrigerant supplied from the outdoor heat exchanger 27 flows in the cooling mode, the check valve 113 → the receiver 110 → the expansion valve 26 → the check valve 114.
→ Flows in the path of the indoor heat exchanger 25.

In the fifth embodiment, the liquid refrigerant is supplied from the receiver 110 to the sub-circuit 37 side, and the other points are the same as those in the third embodiment.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made, for example, the structure of the engine cooling water circuit 41 may be modified appropriately.

[0060]

As is apparent from the above description, according to the present invention, in both cases of cooling and heating, a part of the liquid refrigerant in the liquid reservoir in the main circuit is heated by the refrigerant in the sub circuit. Since it is pressure-fed to the heat exchanger, the exhaust heat of the engine received by the refrigerant heater can be transferred to the indoor heat exchanger in the main circuit during heating, and can be used as an auxiliary heat source for heating, increasing the heating capacity. it can.

On the other hand, during cooling, the jet pressure of the gas refrigerant returned to the discharge side of the compressor in the main circuit through the sub circuit plays an auxiliary role of the compressor for pumping the refrigerant circulating in the main circuit. The circulation of the refrigerant in the circuit can be promoted. Therefore, during cooling, as in the case of heating, the exhaust heat of the engine can be effectively used, the cooling capacity can be improved, and the fuel consumption can be improved.

Moreover, in both cases of cooling and heating,
Since the heat of the engine can be absorbed by the refrigerant heater, the radiator for radiating the heat of the engine can be downsized or eliminated. Furthermore, by downsizing and eliminating this radiator, it is possible to increase the capacity of the outdoor heat exchanger by the amount of the space, which leads to an improvement in cooling and heating capacity. Further, if the radiator can be eliminated, there is an advantage that the piping of the engine cooling water circuit can be simplified.

[Brief description of drawings]

FIG. 1 is a cycle configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a control system.

FIG. 3 is a Mollier diagram showing changes in the state of the refrigerant during heating.

FIG. 4 is a flowchart showing a control flow (No. 1)

FIG. 5 is a flowchart showing a control flow (No. 2)

FIG. 6 is a cycle configuration diagram showing a second embodiment of the present invention.

FIG. 7 is a cycle configuration diagram showing a third embodiment of the present invention.

FIG. 8 is a cycle configuration diagram showing a fourth embodiment of the present invention.

FIG. 9 is a cycle configuration diagram showing a fifth embodiment of the present invention.

[Explanation of symbols]

21 is an engine, 22 is a compressor, 23 is a main circuit,
24 is a four-way switching valve (switching valve), 25 is an indoor heat exchanger,
26 is an expansion valve, 27 is an outdoor heat exchanger, 28 is an accumulator (reservoir), 29 is a pressure switch, 30 to 34
Is a refrigerant temperature sensor, 37 is a sub circuit, 38 is a liquid refrigerant pump (liquid refrigerant pumping means), 39 is a refrigerant heater, 41 is an engine cooling water circuit, 44 is an exhaust heat exchanger, 46 is a throttle opening control motor, Reference numeral 71 is a liquid refrigerant pressure feeding means, 76 is a pressure reducing circuit, 78 is a pressure circuit, 81 is a rotary liquid refrigerant pressure feeding device (liquid refrigerant pressure feeding means), 86 is a pressure circuit, 88 is a pressure reducing circuit, and 91.
Is a reciprocating type liquid refrigerant pump (liquid refrigerant pumping means), 104
Is a four-way switching valve, and 110 is a receiver.

Claims (1)

[Claims] 1. A switching valve, an indoor heat exchanger, an expansion valve, an outdoor heat exchanger and a liquid reservoir are provided in a main circuit for circulating a refrigerant discharged from a compressor driven by an engine. In an engine-driven heat pump type air conditioner configured to perform cooling and heating by switching the circulation direction of the refrigerant in the circuit with the switching valve, in parallel with the main circuit between the liquid reservoir and the discharge side of the compressor. A sub-circuit is provided, and in the sub-circuit, a liquid refrigerant pumping means for pumping the liquid refrigerant supplied from the liquid reservoir,
A refrigerant heater for heating and evaporating the liquid refrigerant pumped by the liquid refrigerant pumping means by the exhaust heat of the engine is provided, and the liquid refrigerant pumping means is operated during cooling and heating. Characteristic engine driven heat pump type air conditioner.