JP3889529B2 - Engine cooling device and gas heat pump type air conditioner equipped with the engine cooling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine cooling device having a three-way valve for preventing overcooling of an engine and a gas heat pump type air conditioner equipped with the engine cooling device.
[0002]
[Prior art]
In general, for example, a gas heat pump type air conditioner includes an engine that drives a compressor (load) and a radiator that circulates cooling water (coolant) of the engine, and the cooling fluid circulation path includes the cooling system. It is known to have an engine cooling device with a three-way valve that bypasses the radiator and circulates coolant through the engine to prevent overcooling of the engine when the water temperature falls below a predetermined temperature. Yes.
[0003]
The three-way valve of this type of engine cooling device, for example, guides all the cooling water to the circulation path via the radiator when the cooling water temperature is higher than a predetermined high temperature side reference temperature (for example, 70 ° C.). When the temperature is lower than the high temperature side reference temperature and approaches a predetermined low temperature side reference temperature (for example, 60 ° C.), more cooling water is led to the circulation path that bypasses the radiator, and when the cooling water temperature is lower than the low temperature side reference temperature By guiding all the cooling water to the circulation path that bypasses the radiator, the cooling water temperature is controlled to be constant and the engine is prevented from being overcooled.
[0004]
[Problems to be solved by the invention]
In a conventional engine cooling device, in order to prevent overheating of the engine, for example, a temperature sensor that detects a cooling water temperature is provided in a cooling water circulation path in the engine or at an outlet thereof, and the cooling detected by the temperature sensor is provided. A device having a mechanism for detecting a high temperature abnormality when the water temperature rises excessively has been proposed.
[0005]
However, for example, when the control valve of the three-way valve stops operating during heating operation, the valve opening is fixed, and the cooling water that has recovered heat from the engine regardless of the cooling water temperature continues to flow through the circulation path via the radiator Since the cooling water temperature is lowered and the engine is supercooled and the inside of the engine is filled with the high-viscosity sludge, for example, the path of the blow-by gas in which the high-viscosity sludge is generated between the piston and the cylinder inside the engine There is a problem in that the engine is adversely affected by clogging or reducing the lubricating ability of engine oil. This phenomenon is prominent in cold regions such as Hokkaido.
[0006]
An object of the present invention has been made in consideration of the above-described circumstances, and provides an engine cooling device capable of preventing engine overcooling due to abnormality of a three-way valve, and a gas heat pump type air conditioner equipped with the engine cooling device. There is to do.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 includes an engine that drives a load and a radiator that circulates the coolant of the engine, and when the temperature of the coolant is below a predetermined temperature in the circulation path of the coolant, In an engine cooling device provided with a three-way valve that bypasses the radiator and circulates the coolant in the engine to prevent overcooling of the engine, the coolant in the coolant circulation path in the engine or at the outlet thereof. A sensor for detecting the temperature, and when the detected temperature of the sensor falls below a reference temperature indicating engine supercooling and the state continues for a predetermined reference time or more, means for outputting a signal indicating abnormality of the three-way valve ; If two reference times are set and the coolant temperature is rising, select a long reference time, and if it is falling, select a short reference time and the state is either selected reference When continued over between an engine cooling system, characterized in that it comprises means for abnormality signals output from the three-way valve.
[0009]
According to a second aspect of the present invention, there is provided a gas heat pump type air conditioner comprising the engine cooling device according to the first aspect.
[0010]
According to these inventions, the sensor for detecting the coolant temperature is provided in the coolant circulation path inside the engine or at the outlet thereof, and the detected temperature of the sensor is lowered to a reference temperature or lower representing the supercooling of the engine. When the state has continued for a predetermined reference time or longer, a means for outputting a signal indicating abnormality of the three-way valve is provided, so that overcooling of the engine due to abnormality of the three-way valve can be detected.
[0011]
According to the invention of claim 1 , two reference times are set, a long reference time is selected when the coolant temperature is rising, a short reference time is selected when the coolant temperature is falling, and the state is selected. When the engine continues for more than one selected reference time, it is equipped with means to output a three-way valve error signal so that when the coolant temperature is falling, the engine overcooling due to the three-way valve error can be detected quickly. it can.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
In FIG. 1, the code | symbol 1 shows a gas heat pump type air conditioner, and this gas heat pump type air conditioner 1 is provided with the engine cooling device 40 mentioned later.
[0014]
The gas heat pump type air conditioner 1 includes an outdoor unit 2 installed outside and a plurality of indoor units 3 installed indoors.
[0015]
The outdoor unit 2 includes a gas engine 11 driven with gas as fuel, a compressor (load) 13 connected to the gas engine 11 via a coupling 12, a four-way valve 14, a receiver tank 15, a heating time An expansion valve 16, an outdoor heat exchanger 17, an outdoor fan 18 that blows air to each outdoor heat exchanger 17 (including a radiator 43 described later), and an accumulator 19 are provided. The indoor unit 3 includes a plurality of indoor heat exchangers 21, an indoor fan 22 that blows air to each indoor heat exchanger 21, and a cooling expansion valve 23 that is provided for each indoor heat exchanger 21. Each component in the outdoor unit 2 and the indoor unit 3 (excluding the fans 18 and 22) is connected by a refrigerant pipe 29. The cooling expansion valve 23 functions as an expansion mechanism only during cooling, and the heating expansion valve 16 functions as an expansion mechanism only during heating operation.
[0016]
The outdoor unit 2 also includes a muffler 31 for silence and an exhaust top 32 as an exhaust device that exhausts exhaust gas from the gas engine 11. The muffler 31 and the exhaust top 32 are sequentially connected from an exhaust gas outlet of the gas engine 11 via an exhaust gas duct 33 extending via a heat exchanger 41 described later.
[0017]
During the heating operation, the refrigerant circulates in the direction of the dotted arrow. That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 13 passes through the four-way valve 14, condenses in the indoor heat exchanger 21, and supplies hot air into the room. The liquid refrigerant condensed (liquefied) in the indoor heat exchanger 21 is decompressed by the heating expansion valve 16 via the cooling expansion valve 23 and the receiver tank 15, and the outdoor heat exchanger 17 performs later-described radiator 21 and Evaporates by absorbing heat from the atmosphere. The evaporated (vaporized) gas refrigerant passes through the four-way valve 14 and the accumulator 19 and returns to the compressor 13.
[0018]
During the cooling operation, the four-way valve 14 is switched and the refrigerant circulates in the direction of the solid arrow. That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 13 passes through the four-way valve 14, and is condensed (liquefied) by the ventilation from the outdoor blower 18 in the outdoor heat exchanger 17. The liquid refrigerant condensed in the outdoor heat exchanger 17 is depressurized by the cooling expansion valve 23 via the heating expansion valve 16 and the receiver tank 15, evaporated (vaporized) by the indoor heat exchanger 21, and cool air is blown into the room. Supply. The evaporated gas refrigerant returns to the compressor 13 through the four-way valve 14 and the accumulator 19.
[0019]
Exhaust gas exhausted when the gas engine 11 is driven is cooled by a heat exchanger 41 to be described later, is sent to the exhaust top 32 through the muffler 31, and is discharged from the outlet of the exhaust top 32 to the outside. The exhaust gas temperature is a high temperature of 500 ° C. or higher at the outlet of the gas engine 11, and this energy is also cooled as 100 ° C. or lower in the heat exchanger 41 in order to be used as a heat source for heating.
[0020]
The outdoor unit 2 includes a gas engine 11 and an engine cooling device 40 that cools exhaust gas generated in the gas engine 11 with cooling water (coolant).
[0021]
In the engine cooling device 40, the gas engine 11, a heat exchanger 41 provided in the gas engine 11, a wax three-way valve (three-way valve) 42, a radiator 43, and a water pump 44 are indicated by wavy lines. They are connected by a water pipe 45. In addition, a temperature sensor (for example, a thermistor) 51 that detects the coolant temperature at the outlet of the gas engine 11 is provided in the water pipe 45 a between the gas engine 11 and the wax three-way valve 42. The temperature sensor 51 may be provided inside the gas engine 11. Reference numeral 61 denotes a control device (means for outputting a signal indicating abnormality of the three-way valve, determination means) that controls the gas heat pump type air conditioner 1, and the control device 61 includes a timer 62.
[0022]
In the gas heat pump type air conditioner 1, the heat released from the cooling water by the radiator 43 is recovered by the refrigerant flowing through the outdoor heat exchanger 18, and the heating efficiency of the gas heat pump type air conditioner 1 is improved. ing.
[0023]
The wax three-way valve 42 is a three-way valve that operates a control valve using wax (not shown) that expands and contracts according to the temperature of the cooling water flowing into the wax three-way valve 42 to increase or decrease the valve opening. is there.
[0024]
When the gas engine 11 is driven, the cooling water discharged from the water pump 44 flows to the heat exchanger 41 and the gas engine 11 to cool the gas engine 11 and the exhaust gas. At this time, the cooling water whose temperature has risen is led out from the gas engine 11 and flows into the wax three-way valve 42. The wax three-way valve 42 switches between a high-temperature circulation path indicated by a black arrow and a low-temperature circulation path indicated by a white arrow according to the cooling water temperature. The high-temperature circulation path is a circulation path that returns from the wax three-way valve 42 to the water pump 44 via the radiator 43. If cooling water is passed through the high-temperature circulation path, the heat is radiated by the radiator 43 and the cooling water temperature is lowered. To do. The low-temperature circulation path is a circulation path that bypasses the radiator 43 from the wax three-way valve 42 and returns directly to the water pump 44. If the cooling water flows through this low-temperature circulation path, the cooling water temperature rises.
[0025]
In this embodiment, the wax three-way valve 42 circulates at a high temperature via a radiator when the temperature of the cooling water flowing into the wax three-way valve 42 is higher than a predetermined high temperature side reference temperature (for example, 70 ° C.). All cooling water is guided to the path, and more cooling water is guided to the low temperature circulation path that bypasses the radiator as the cooling water temperature falls below the high temperature reference temperature and approaches a predetermined low temperature reference temperature (for example, 60 ° C). When the cooling water temperature is equal to or lower than the low-temperature side reference temperature, the cooling water temperature is controlled to be constant by guiding all the cooling water to a low-temperature circulation path that bypasses the radiator.
[0026]
However, for example, during the heating operation, the control valve of the wax three-way valve 42 stops operating for some reason, the valve opening is fixed, and the cooling water that has recovered the heat from the gas engine 11 is connected to the radiator 43 regardless of the cooling water temperature. When it continues to flow through the high-temperature circulation path that passes through, the temperature of the gas engine 11 is lowered to be in a supercooled state, the inside of the engine is filled with sludge having a high viscosity, and the gas engine 11 is adversely affected.
[0027]
FIG. 2 is a flowchart showing the operation of the control device that detects an abnormality of the wax three-way valve 42.
[0028]
The control device 61 includes a memory (not shown). In this memory, the latest cooling water temperature t0 measured by the temperature sensor 51, the cooling water temperature t1 measured one time before, and the previous two times. The measured cooling water temperature t2 can be stored.
[0029]
When the power of the gas heat pump type air conditioner 1 is turned on (S1), first, the control device 61 sets initial values (for example, −30 ° C.) for the cooling water temperatures t0 to t2 (S2). The initial value is determined to be as low as possible since an increase in the coolant temperature is determined based on this initial value. Next, the control device 61 determines whether or not the gas engine 11 is in operation (S3). When the gas engine 11 has stopped operating, the control device 61 waits until the gas engine 11 starts operating. When the gas engine 11 starts operation, the control device 61 inputs the value of the cooling water temperature t1 to the cooling water temperature t2, inputs the value of the cooling water temperature t0 to the cooling water temperature t1, and sets the temperature to the cooling water temperature t0. The latest (current) cooling water temperature measured by the sensor 51 is input to update the cooling water temperature t2, the cooling water temperature t1, and the cooling water temperature t0 (S4). And the control apparatus 61 determines whether the newest cooling water temperature t0 is below a predetermined supercooling reference temperature (for example, 60 degreeC) (S5). This predetermined subcooling reference temperature is a reference temperature representing the supercooling of the gas engine 11, and need not be set to a temperature equal to the low temperature side reference temperature.
[0030]
If it is determined in step S5 that the latest cooling water temperature t0 is greater than the predetermined supercooling reference temperature, the control device 61 clears the time measured by the timer 62 (S9). Then, steps S3 to S6 are repeated as long as the latest cooling water temperature t0 continues to be higher than the predetermined supercooling reference temperature. That is, when the wax three-way valve 42 is operating normally, the temperature of the cooling water flowing into the wax three-way valve 42 is controlled to a constant temperature higher than a predetermined supercooling reference temperature, so steps S3 to S6 are performed. Will repeat.
[0031]
When it is determined in step S5 that the latest cooling water temperature t0 is equal to or lower than the predetermined supercooling reference temperature, the control device 61 turns on the timer 62 and starts measuring time (S7). The cooling water temperature t0 is compared (S8).
[0032]
When it is determined in step S8 that the latest cooling water temperature t0 is equal to or higher than the cooling water temperature t2, that is, when the temperature of the cooling water detected by the temperature sensor 51 is increasing, the control device 61 uses the timer 62. It is determined whether or not a predetermined time supercooling reference time (for example, 10 minutes) has elapsed (S9). Thereafter, when the cooling water temperature has risen, the time until the latest cooling water temperature t0 rises to a predetermined supercooling reference temperature or until the time measured by the timer 62 exceeds the predetermined supercooling reference time. Until then, steps S3 to S5 and S7 to S9 are repeated. For example, when the gas heat pump type air conditioner 1 is activated, if the wax three-way valve 42 is operating normally, steps S3 to S5, S7 to S7 until the cooling water temperature t0 rises above a predetermined supercooling reference temperature. S9 is repeated, and the latest cooling water temperature t0 rises above the predetermined supercooling reference temperature before the time measured by the timer 62 elapses the predetermined supercooling reference time. Thereafter, the cooling water temperature is maintained at a temperature higher than a predetermined supercooling reference temperature, and steps S3 to S6 are repeated.
[0033]
However, for example, when the gas heat pump type air conditioner 1 is activated, the control valve of the wax three-way valve 42 does not operate, the valve opening is fixed, and the cooling water may continue to flow through the high-temperature circulation path via the radiator 43. is there. In such a case, the cooling water temperature rises only slowly.
[0034]
When the cooling water temperature is equal to or lower than the supercooling reference temperature and the rise in the cooling water temperature is moderate (including the stagnation state), the control device 61 determines that the latest cooling water temperature t0 is a predetermined supercooling reference in step S5. In step S8, it is determined that the latest cooling water temperature t0 is equal to or higher than the cooling water temperature t2, that is, the cooling water temperature is rising. Then, the control device 61 determines whether or not the time measured by the timer 62 has passed a predetermined rising supercooling reference time (for example, 10 minutes) (S9). After that, the control device 61 repeats steps S3 to S9 until the time measured by the timer 62 elapses a predetermined rising supercooling reference time. When the time measured by the timer 62 exceeds the predetermined supercooling reference time when the latest cooling water temperature t0 is equal to or lower than the predetermined supercooling reference temperature, the controller 61 determines that the wax three-way valve 42 is It is determined that there is an abnormality, and a three-way valve abnormality signal is output. For example, an error display or the like is performed to forcibly terminate the operation of the gas engine 11 (S10), and the time measured by the timer 62 is cleared (S11). (S12).
[0035]
As another case, for example, the wax three-way valve 42 was operating normally at the start of operation of the gas engine 11, but the valve opening degree was fixed to the wax three-way valve 42 after the cooling water temperature once increased. In some cases, the cooling water continues to flow through the circulation path at a higher temperature than necessary. In this case, the cooling water temperature falls.
[0036]
When the cooling water temperature is decreasing, when the temperature falls below the predetermined supercooling reference temperature, the control device 61 determines in step S5 that the latest cooling water temperature t0 is equal to or lower than the predetermined supercooling reference temperature, In S8, it is determined that the latest cooling water temperature t0 is equal to or lower than the cooling water temperature t2, that is, the cooling water temperature is decreasing. Then, the control device 61 determines whether or not the time measured by the timer 62 has exceeded the descent supercooling reference time (for example, 5 minutes) (S13). The descent supercooling reference time is set to a time shorter than the ascending supercooling reference time (for example, 10 minutes). Thereafter, the control device 61 repeats steps S3 to S8 and S13 when the time measured by the timer 62 has not exceeded the predetermined descent supercooling reference time.
[0037]
When the time measured by the timer 62 exceeds a predetermined descent supercooling reference time, the control device 61 determines that the wax three-way valve 42 is abnormal and outputs a three-way valve abnormality signal, for example, an error display or the like. To forcibly terminate the operation of the gas engine 11 (S10). And the control apparatus 61 clears the time-measurement time of the timer 62 (S11), and complete | finishes (S12).
[0038]
As another case, for example, when the valve opening degree is fixed to the wax three-way valve 42, the cooling water temperature is repeatedly raised, stagnated, lowered or the like when the cooling water temperature is lower than a predetermined supercooling reference temperature. However, in any case, if the cooling water temperature continues below the predetermined supercooling reference temperature, the control device 61 causes the timer 62 to measure the predetermined time when the timer 62 is overcooled in step S9. It is determined that the reference time has elapsed, or it is determined in step S13 that the time measured by the timer 62 has passed the predetermined cooling subcooling reference time, and it is determined that the wax three-way valve 42 is abnormal and the three-way valve is abnormal. A signal is output (S10). And the control apparatus 61 clears the timer 62 (S11), and complete | finishes (S12).
[0039]
In the present embodiment, a temperature sensor 51 that detects the cooling water temperature is provided in the circulation path of the cooling water inside or at the outlet of the gas engine 11, and the temperature detected by the temperature sensor 51 is a predetermined value that indicates overcooling of the gas engine 11. A three-way valve abnormality signal indicating that the wax three-way valve 42 is abnormal is output when the temperature drops below the supercooling reference temperature and the state continues for a predetermined rising supercooling reference time or lowering supercooling reference time. Therefore, it can be detected that the gas engine 11 is in a supercooled state due to the abnormality of the wax three-way valve 42. Therefore, when the three-way valve abnormality signal is output, for example, if the operation of the gas engine 11 is forcibly terminated, the engine is prevented from being overcooled due to the abnormality of the wax three-way valve 42 and sludge having a high viscosity inside the gas engine 11 Can be prevented.
[0040]
In addition, when the cooling water temperature detected by the temperature sensor 51 is decreasing, a descent supercooling reference time that is shorter than the ascending supercooling reference time is set, and a state in which the cooling water temperature is falling is predetermined. Since the wax three-way valve 42 is determined to be abnormal if it continues for a predetermined descent time that is shorter than the ascending supercooling reference time, it is possible to quickly detect abnormality of the wax three-way valve 42 when the cooling water temperature drops.
[0041]
In addition, the temperature sensor 51 that detects the cooling water temperature and the control device 61 that controls the air conditioner 1 are components conventionally used. In the present embodiment, the temperature sensor 51 and the control device 61 Since the abnormality of the wax three-way valve 42 is detected, it is not necessary to add a new component, and the abnormality of the wax three-way valve 42 can be detected at a low cost.
[0042]
As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this. In this embodiment, the wax three-way valve 42 is used as the three-way valve. However, for example, a three-way valve whose valve opening degree is controlled by a thermostat or a three-way valve using a thermo valve may be used. Further, in this embodiment, when the cooling water temperature is rising, a predetermined rising supercooling reference time is applied, and when the cooling water temperature is falling, a predetermined falling supercooling reference time is applied. However, for example, a predetermined rising supercooling reference time may be applied when the cooling water temperature is rising or falling. Moreover, in this embodiment, although the engine cooling device 40 is applied to the gas heat pump type air conditioner 1, the engine cooling device 40 is applied to, for example, a showcase using a cogeneration system or a gas heat pump type refrigerator. Is possible.
[0043]
【The invention's effect】
According to the present invention, a sensor for detecting the coolant temperature is provided in the coolant circulation path in the engine or at the outlet thereof, and the detected temperature of the sensor is lowered below a reference temperature representing engine supercooling. Is provided with means for outputting a signal indicating the abnormality of the three-way valve when the engine continues for a predetermined reference time or more, so that it is possible to detect engine overcooling due to the abnormality of the three-way valve.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a gas heat pump type air conditioner equipped with an engine cooling device according to the present embodiment.
FIG. 2 is a flowchart showing the operation of a control device that detects an abnormality of a three-way valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas heat pump type air conditioning apparatus 2 Outdoor unit 3 Indoor unit 11 Gas engine 40 Engine cooling device 42 Wax three-way valve 43 Radiator 51 Temperature sensor 61 Control device

Claims (2)

An engine that drives the load, and a radiator that circulates the coolant of the engine, and bypasses the radiator when the temperature of the coolant falls below a predetermined temperature in the circulation path of the coolant. In the engine cooling device provided with a three-way valve that circulates coolant through the engine and prevents overcooling of the engine,
A sensor for detecting the coolant temperature is provided in the coolant circulation path in the engine or at the outlet of the engine, and the detected temperature of the sensor falls below a reference temperature indicating engine overcooling. When the above continues , means for outputting a signal of the abnormality of the three-way valve ;
Set two reference times, if the coolant temperature is rising, select a long reference time, if it is falling, select a short reference time and the state will continue for more than one selected reference time And a means for outputting a signal indicating an abnormality of the three-way valve . A gas heat pump type air conditioner comprising the engine cooling device according to claim 1.

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