JP2004285836A - Engine drive heat pump provided with total region air-fuel ratio sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent atmospheric calibration operation from being improperly executed during maintenance operation with respect to an engine drive heat pump in which a degree of change in lapse time of a sensor is measured by regularly performing the atmospheric calibration of a UEGO sensor. <P>SOLUTION: Immediately before the atmospheric calibration of the UEGO sensor, an outdoor fan 15, a ventilation fan 7, and a cooling water pump are driven thereby warning an auditory sense and a visual sense of a maintenance operator about performing of the atmospheric calibration. Accordingly, during the maintenance work, attention of the worker is called. Further, the atmospheric calibration operation is performed when all of indoor units are in a thermo-off stop state and an outdoor unit is forcibly stopped. The atmospheric calibration is performed at a timing with a little possibility of existence of the maintenance worker near a GHP. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a full-range air-fuel ratio sensor (hereinafter, this sensor is capable of recognizing an air-fuel ratio of an air-fuel mixture by detecting an oxygen concentration in engine exhaust gas over a wide range from a lean region to a rich region. The present invention relates to an engine-driven heat pump including a UEGO sensor (referred to as a Universal A / F Heated Exhaust Gas Oxygen Sensor). In particular, the present invention relates to an improvement in the operation of the UEGO sensor during atmospheric calibration.
[0002]
[Prior art]
Conventionally, an engine driven heat pump represented by GHP (Gas Heat Pump) has been known. The GHP includes a gas engine and a refrigerant circuit that circulates a refrigerant by a compressor (compressor) that receives the power of the gas engine, as shown in Patent Document 1 below. By utilizing heat effectively, there is an advantage that the heating capacity is improved and a defrost (defrost) operation is not required.
[0003]
Further, in this GHP engine, an oxygen concentration sensor is provided in the exhaust system, and the air-fuel ratio of the air-fuel mixture is recognized by detecting the oxygen concentration in the exhaust gas, and the fuel supply amount is fed back accordingly. Control is being done. That is, the fuel supply amount is adjusted based on the detected oxygen concentration in the exhaust gas to control the air-fuel ratio of the air-fuel mixture to a target value, thereby reducing CO, NOx, and HC in the exhaust gas, and improving the thermal efficiency of the engine. Is being improved.
[0004]
As an oxygen concentration sensor, a UEGO sensor disclosed in Patent Literature 2 below is known. In recent years, attention has been paid to providing this UEGO sensor in an exhaust system of a GHP engine.
[0005]
The feature of this UEGO sensor is that it can detect the oxygen concentration in the exhaust gas in a wide range from the lean region to the rich region of the mixture, and can recognize the air-fuel ratio of the mixture continuously over a wide range. . The operating principle of this UEGO sensor is disclosed in Patent Document 2 below.
[0006]
[Patent Document 1]
JP-A-2000-179983
[Patent Document 2]
JP 2000-81416 A
[0007]
[Problems to be solved by the invention]
By the way, as a characteristic of the above-mentioned UEGO sensor, there is almost no change with time when applied to an engine in which combustion is performed with an air-fuel mixture near the stoichiometric air-fuel ratio. However, when the present invention is applied to an engine that burns with an air-fuel mixture having an air-fuel ratio that largely deviates from the stoichiometric air-fuel ratio (for example, when it is applied to an engine that performs a lean burn operation), a temporal change occurs. In particular, it has a characteristic that the change at the beginning of use rapidly proceeds.
[0008]
FIG. 9 shows a state of a temporal change when the UEGO sensor is applied to an engine that performs a lean burn operation. In FIG. 9, the horizontal axis represents time, and the vertical axis represents the output level (current value) of the UEGO sensor. When the lean burn is performed at a constant air-fuel ratio, the output level of the UEGO sensor decreases. (Lower output level with time). As described above, when applied to an engine that performs lean burn operation, the output level of the UEGO sensor has such a characteristic that the change at the beginning of use rapidly progresses, and then the progress of the change becomes gradual.
[0009]
Heretofore, this type of UEGO sensor has been applied to automotive engines. The reason is that the UEGO sensor has the above-mentioned aging characteristics. That is, in a general automobile engine, the target value of the air-fuel ratio is set to the stoichiometric air-fuel ratio (about 15: 1 in the case of a gasoline engine). There is no. The durability (lifetime) required of an oxygen concentration sensor applied to an automobile engine is assumed to be 100,000 miles and travel at an average speed of 40 km / h. It is short, and it is unlikely that it will change over time during this time.
[0010]
By the way, when this UEGO sensor is applied to engines other than those for automobiles, there may be a situation where the above-mentioned change over time cannot be ignored. In particular, as described above, this is a case where the present invention is applied to a GHP gas engine. That is, the GHP gas engine generally performs a lean burn operation in order to realize a configuration in which the exhaust system is not provided with an exhaust gas purification device such as a three-way catalyst. That is, by performing the lean burn operation, the combustion temperature is suppressed, and the generation of NOx can be suppressed. For example, in a gas engine using city gas (13A), an operation is performed with an air-fuel ratio of about 18: 1 (the stoichiometric air-fuel ratio is about 11: 1) set as a target value. Further, the durability required of the oxygen concentration sensor applied to the gas engine is as long as about 30,000 hours, and it is conceivable that there is a possibility that the oxygen concentration sensor greatly changes with time.
[0011]
FIG. 10 shows the sensor output level (current value) of the UEGO sensor according to the excess air ratio (a value correlated with the oxygen concentration in the exhaust gas). In this figure, the solid line shows the relationship between the excess air ratio and the sensor output level when the UEGO sensor is new (having no change over time), and the broken line shows the change over time in the UEGO sensor (for example, a change over time of about 10%). 4) shows the relationship between the excess air ratio and the sensor output level when () occurs.
[0012]
As can be seen from this figure, even when the sensor output level is the same, the actual excess air ratio is different between the case where the UEGO sensor is new and the case where the UEGO sensor has changed over time. That is, for example, when the UEGO sensor is new and the sensor output level is A in the figure, it is recognized that the excess air ratio is B. Since the UEGO sensor has not changed over time, the excess air ratio is accurately recognized, and the actual excess air ratio in the exhaust pipe is also B. However, when the sensor output level of the UEGO sensor that changes with time is A in the figure, the UEGO sensor recognizes that the excess air ratio is B, but the actual excess air ratio is C. Thus, an error occurs in the recognition of the excess air ratio depending on the state of the change.
[0013]
Now, it is assumed that the air-fuel ratio has reached the target value when the excess air ratio is B, and that the actual excess air ratio in the exhaust pipe is also B. In this case, when the UEGO sensor is new, it is correctly recognized that the sensor output level is A and the excess air ratio is B. Based on this recognition, it is determined that the current air-fuel ratio matches the target value, and the current fuel supply amount is maintained. On the other hand, when the UEGO sensor is changing with time, the sensor output level is D (the actual excess air ratio is B, but the sensor output is reduced due to the change with time, and the output value is D). ), The sensor erroneously recognizes that the excess air ratio is E. In this case, it is determined that the current air-fuel ratio is rich with respect to the target value, and the control for reducing the fuel supply amount is executed. The actual current air-fuel ratio is the target value, and the control to reduce the fuel supply amount is executed for this. Therefore, the actual air-fuel ratio shifts greatly from the target value to the lean side. In some cases, the air-fuel ratio reaches the misfire limit and the engine operation cannot be continued.
[0014]
As described above, when an air-fuel ratio control system including a UEGO sensor is to be applied to a gas engine for GHP, it is difficult to put the UEGO sensor into practical use unless the problem of aging of the UEGO sensor is solved.
[0015]
In view of this point, an atmospheric calibration operation for sensing the UEGO sensor in the atmosphere is periodically performed, and the degree of change with time is measured based on the sensor output at that time. As a result, a technique has been proposed which recognizes a change in the output level of the UEGO sensor over time and recognizes the excess air ratio in the exhaust gas in consideration of the change (Japanese Patent Application No. 2002-318051). ). According to this technique, the air-fuel ratio can always be controlled to the target excess air ratio regardless of the degree of the temporal change of the UEGO sensor.
[0016]
Specifically, while the GHP is stopped, the atmosphere is introduced into the exhaust path by performing the cranking operation of the engine in a state where the fuel supply is prohibited, and the atmospheric calibration operation is performed. When the atmospheric calibration operation of the UEGO sensor is performed by cranking as described above, it is possible to perform the sensing operation of the UEGO sensor in the atmospheric atmosphere without providing the engine with a special blower or an air introduction path. It becomes possible.
[0017]
By the way, the GHP requires periodic maintenance of the outdoor unit, and during this maintenance, the maintenance worker removes the outer plate of the GHP outdoor unit and performs maintenance on the engine and peripheral devices. .
[0018]
Usually, it is instructed by a maintenance manual or the like that the maintenance work is performed with the power supply (main switch) of the GHP outdoor unit turned off. However, some workers perform the maintenance work without turning off the power supply. There is. For this reason, if the integrated operation time of the GHP before the maintenance work has reached the air calibration execution timing (for example, if 450 hours have elapsed since the previous air calibration), the air calibration operation is not performed during the maintenance work. It will be executed easily. In other words, the engine is cranked during the maintenance work by the worker, which may hinder the maintenance work or surprise the maintenance worker.
[0019]
The present invention has been made in view of such a point, and an object thereof is to provide an engine-driven heat pump configured to periodically calibrate the atmosphere of a UEGO sensor and measure the degree of change with time of the sensor. An object of the present invention is to make a maintenance worker recognize that atmospheric calibration is performed, or to execute an atmospheric calibration operation at a timing when there is a low possibility that a maintenance operation is being performed.
[0020]
[Means for Solving the Problems]
-Summary of the invention-
In order to achieve the above-mentioned object, the present invention provides a method of warning during maintenance work that the atmosphere calibration is to be performed immediately before the start of the atmosphere calibration, by alerting the maintenance worker of hearing and vision. The worker can be alerted. In addition, the atmospheric calibration is performed at a timing when the possibility that the maintenance work is performed is low or when the maintenance worker expects that the engine may be started. Thus, it is possible to prevent the atmosphere calibration operation from being performed carelessly during the maintenance operation (operations that the maintenance operator does not expect).
[0021]
-Solution-
Specifically, it is assumed that an engine-driven heat pump is driven by an engine having an exhaust gas system provided with an all-area air-fuel ratio sensor. A warning is issued to the engine-driven heat pump to perform a warning operation to warn of the execution of the air calibration immediately before performing the air calibration in which the atmosphere is introduced into the exhaust system and the sensing operation of the air-fuel ratio sensor is performed over the entire area. Means are provided.
[0022]
According to this specific matter, if the air calibration of the entire area air-fuel ratio sensor becomes necessary due to the accumulated operation time of the engine reaching a predetermined time or the like, a warning is first issued before executing the air calibration (engine cranking). The means is activated to execute a predetermined warning operation. As the warning operation, an operation that appeals to the hearing or vision of the worker when the maintenance operation is being performed is listed. For example, as a warning operation for hearing, an outdoor fan, a ventilation fan (warning by a wind noise or a motor sound), a cooling water pump (a warning by a motor sound) or the like is driven, or an alarm buzzer is provided and provided. Sounding is raised. On the other hand, as a visual warning operation, in addition to driving the outdoor fan in the same manner as described above, a display unit (such as a liquid crystal display unit) is provided on the operation panel of the outdoor unit (heat pump heat source side unit) and the display unit is provided. The notice of the execution of the atmospheric calibration is displayed in advance. Thus, the maintenance worker is aware that the atmospheric calibration may be started, and it is not surprising that the engine is subsequently cranked. As a result, the maintenance worker performs the coping operation. For example, when the maintenance work is stopped or the maintenance work is performed, it is determined that the power of the outdoor unit must be turned off, and the power supply is turned off after the atmospheric calibration is completed to perform the maintenance work.
[0023]
Further, as described above, a specific configuration for driving the outdoor fan, the ventilation fan, the cooling water pump, and the like before the execution of the atmospheric calibration is as follows. That is, after the engine is stopped, restarting is prohibited for a predetermined time, and at the time of restarting, at least one of the outdoor fan, the ventilation fan, and the cooling water pump provided in the heat pump heat source side unit is provided. The engine is started after the preparatory operation in which one is driven for a predetermined time is performed. When the air calibration of the full-range air-fuel ratio sensor is performed, the warning unit performs the preliminary operation after a time substantially equivalent to the predetermined time has elapsed after the engine is stopped, and then the air calibration is started. It is configured so that:
[0024]
According to this specific matter, when performing the atmospheric calibration of the full range air-fuel ratio sensor, the same preliminary operation as the normal engine start is performed. For example, if a worker is performing maintenance work without knowing that the engine-driven heat pump has the air calibration function for the full range air-fuel ratio sensor, during the maintenance work, the same preliminary operation as normal engine startup can be performed. When this operation is performed, the operator recognizes that the engine is started, and performs the maintenance operation with the maintenance operation stopped or with caution. Also in this case, the maintenance worker is not surprised by the careless operation of the atmosphere.
[0025]
In addition, as a configuration in the case where the atmospheric calibration is performed at a timing when the possibility that the maintenance work is performed is low, the following is listed. In other words, an engine driven heat pump that uses an engine having an exhaust gas air-fuel ratio sensor in the exhaust system as a drive source and circulates a heat medium between the heat pump heat source side unit and the heat pump user side unit in response to a request from the heat pump user side unit. It is assumed. With respect to this engine-driven heat pump, atmospheric calibration for introducing air into the exhaust system and performing sensing operation of the air-fuel ratio sensor in all regions is performed while all of the units using the heat pump are in the thermo-off state.
[0026]
In addition, an engine-driven heat pump that uses an engine having an exhaust gas air-fuel ratio sensor in the exhaust system as a drive source and circulates a heat medium between the heat pump heat source side unit and the heat pump user side unit in response to a request from the heat pump user side unit. It is assumed. For this engine-driven heat pump, the air calibration is performed to introduce the atmosphere into the exhaust system and perform the sensing operation of the air-fuel ratio sensor over the entire area.When there is a heat medium circulation request from the heat pump utilization side unit, the heat pump heat source side unit is It is executed in the state where it is forcibly stopped.
[0027]
According to these specific items, the air calibration of the full area air-fuel ratio sensor is executed at the timing when the heat pump utilization side unit requests the circulation of the heat medium (refrigerant). If the unit using the heat pump requires the circulation of the heat medium, the maintenance work is unlikely to be performed, so the maintenance worker may be present near the unit using the heat pump at the start of the atmospheric calibration. There is little sex. As a result, there is almost no problem even if the atmospheric calibration is started without executing the warning operation as in the above-described solution. In the case where the atmospheric calibration is performed at this timing, there is no possibility that the maintenance worker is not present near the heat pump utilization side unit at the time of the start of the atmospheric calibration. Therefore, the warning operation is also performed in this case. Is more preferred. Note that in the present invention, in a situation where all the heat pump utilization side units are stopped (a situation where there is no request for circulation of the heat medium due to a remote control OFF operation or the like), the atmospheric calibration of the full area air-fuel ratio sensor is not executed. To This is because there is a high possibility that maintenance work is being performed when all the heat pump utilization side units are stopped.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case will be described in which the present invention is applied to a GHP in which a gas engine drives a refrigerant compressor as an engine-driven heat pump.
[0029]
-Overall configuration of GHP outdoor unit-
FIG. 1 is a perspective view showing the internal configuration of the GHP outdoor unit according to the present embodiment, FIG. 2 is a front view thereof, and FIG. 3 is a plan view thereof. FIG. 4 is a circuit diagram showing the GHP refrigerant circuit 20 and the engine cooling water circuit 30.
[0030]
As shown in these figures, the package 4 of the GHP outdoor unit is composed of two device chambers 1 and 2 which are divided into upper and lower parts. The upper part is the heat exchange chamber 1 and the lower part is the engine room 2. . Here, the heat exchange chamber 1 is a chamber through which outside air can flow for heat exchange, which will be described later, and the engine room 2 is in a substantially sealed state that is connected to the outside only through a ventilation port, an intake pipe, and an exhaust pipe.
[0031]
Further, the separate plate 71 separating the heat exchange chamber 1 and the engine room 2 is made of two upper and lower plate members, each having a communication hole (not shown) for communicating the heat exchange chamber 1 and the engine room 2. ing. A ventilation fan 7 is provided in the communication hole. That is, outside air is introduced from a ventilation opening (not shown) of the engine room 2 by driving the ventilation fan 7, and after the outside air ventilates the inside of the engine room 2, it is introduced into the heat exchange chamber 1 through the communication hole. It has become. It should be noted that an outside air temperature sensor is provided inside the ventilation port.
[0032]
An engine 31, a refrigerant compressor 21, an accumulator 27, and the like are installed in the engine room 2, and the engine 31 is provided with an intake silencer 8, an exhaust silencer 9, and the like. An oil pan 5 for storing lubricating oil for the engine 31 and an auxiliary oil pan 6 communicating with the oil pan 5 are arranged near the bottom of the engine 31. In the engine room 2, an electrical component box 11 in which electrical components such as a control device are accommodated, and a pipe constituting a refrigerant circuit 20, which will be described later, are installed. An oil tank 10 storing oil is arranged.
[0033]
The oil tank 10 and the auxiliary oil pan 6 are connected to each other, and the lubricating oil stored in the oil tank 10 is replenished to the auxiliary oil pan 6 by a lubricating oil pump 18 interposed in the middle of the connection. It is configured.
[0034]
In the heat exchange chamber 1 provided above the engine room 2, an outdoor heat exchanger 22 and a radiator 35 provided in each of the circuits 20 and 30 described below are installed. On the ceiling surface of the heat exchange chamber 1, outdoor fans 15, 15 for heat radiation are provided, and an exhaust port 14 is opened to exhaust air from the engine 31 after passing through the exhaust silencer 9. Is discharged from the exhaust port 14 to the outside.
[0035]
-Circuit description-
Next, the refrigerant circuit 20 and the engine cooling water circuit 30 will be described with reference to FIG.
[0036]
(Refrigerant circuit 20)
The refrigerant circuit 20 includes a refrigerant compressor 21 linked to an engine 31 by a belt transmission. That is, the refrigerant compressor 21 operates by receiving the driving force of the engine 31.
[0037]
The refrigerant circuit 20 includes the refrigerant compressor 21, an outdoor heat exchanger 22, and a plurality of indoor heat exchangers 23, 23,. The four-way valve 24 is connected to a discharge line 41 connected to the suction line 21a and a suction line 42 connected to the suction part 21b. That is, by switching the four-way valve 24, the outdoor heat exchanger 22 is connected to the discharge line 41, the indoor heat exchanger 23 is connected to the suction line 42, and the indoor heat exchanger 23 is connected to the discharge line 41. The heat exchanger 22 can be switched to a heating operation mode in which the heat exchanger 22 is connected to the suction line 42.
[0038]
Expansion pipes 25 and 26 are provided on the liquid side pipes of both heat exchangers 22 and 23. During the cooling operation, the refrigerant flows as indicated by solid-line arrows in the drawing and condenses in the outdoor heat exchanger 22. The expanded liquid refrigerant expands at the indoor expansion valve 26 and reaches the indoor heat exchanger 23. On the other hand, during the heating operation, the refrigerant flows as indicated by the dashed arrow in the drawing, and the liquid refrigerant condensed in the indoor heat exchanger 23 expands in the outdoor expansion valve 25 and reaches the outdoor heat exchanger 22. I have. A specific refrigerant circulation operation will be described later.
[0039]
The suction line 42 is provided with an accumulator 27. The accumulator 27 separates the refrigerant into gas and liquid, and sucks only the gas refrigerant into the refrigerant compressor 21.
[0040]
An auxiliary refrigerant evaporator 28 is provided upstream of the accumulator 27 in the suction line 42. The refrigerant auxiliary evaporator 28 performs heat exchange between the refrigerant flowing through the suction line 42 and the engine cooling water during the heating operation, and provides heat of the engine cooling water (engine exhaust heat) to the refrigerant. Thus, the degree of superheat (superheat) is given to the suction refrigerant, thereby improving the heating capacity. When the refrigerant flowing through the suction line 42 is in a gas-liquid mixed state, the auxiliary refrigerant evaporator 28 also contributes to the vaporization of the liquid refrigerant. Thereby, the liquid back phenomenon to the refrigerant compressor 21 can be reliably prevented.
[0041]
The refrigerant circuit 20 includes a bypass pipe 29 that forms a bypass flow path for flowing the refrigerant so as to bypass the auxiliary refrigerant evaporator 28. One end (upstream end) of the bypass pipe 29 is connected between the indoor heat exchanger 23 and the four-way valve 24, and the other end (downstream end) is directly connected to the upper part of the accumulator 27. The bypass pipe 29 is provided with an electromagnetic valve 29a. During the heating operation, the electromagnetic valve 29a is closed to exchange heat in the auxiliary refrigerant evaporator 28 (the refrigerant flowing through the suction line 42 and the engine cooling water). Heat exchange with the engine) to recover the engine exhaust heat to the refrigerant, while it is not necessary to recover the engine exhaust heat during the cooling operation. Therefore, the solenoid valve 29a is opened to allow a part or all of the refrigerant to be cooled. The auxiliary evaporator 28 is bypassed.
[0042]
(Engine cooling water circuit 30)
Next, the engine cooling water circuit 30 will be described. The engine cooling water circuit 30 includes a cooling water pump 32 serving as a driving source for circulating the engine cooling water. A cooling water passage (water jacket), a thermostat 33, a three-way valve 34, a radiator 35, and an exhaust gas heat exchanger 36 are connected.
[0043]
A relief pipe 33 a is connected to the thermostat 33, and a downstream end of the relief pipe 33 a is connected to an upstream side of the exhaust gas heat exchanger 36. The thermostat 33 allows the cooling water to flow through the relief pipe 33a when the temperature of the engine cooling water is lower than, for example, 60 ° C. (for example, at the beginning of engine start). The engine cooling water is directed toward.
[0044]
The three-way valve 34 has three ports: a cooling water inlet 34a, a first cooling water outlet 34b, and a second cooling water outlet 34c. The cooling water inlet 34a communicates with the thermostat 33, the first cooling water outlet 34b communicates with the radiator 35, and the second cooling water outlet 34c communicates with the auxiliary refrigerant evaporator 28 via the cooling water supply pipe 28a. . Further, the three-way valve 34 is configured by an adjustment valve that can change an opening ratio between the first cooling water outlet 34b and the second cooling water outlet 34c.
[0045]
The auxiliary refrigerant evaporator 28 and the upstream side of the exhaust gas heat exchanger 36 are connected by a cooling water return pipe 28b, and the cooling water that gives heat to the refrigerant in the auxiliary refrigerant evaporator 28 returns to the cooling water. The cooling water pump 32 is returned to the suction side by a pipe 28b.
[0046]
-Driving operation-
Next, the circulation operation in the refrigerant circuit 20 and the cooling water circuit 30 configured as described above will be described.
[0047]
(Cooling operation)
First, the operation during the cooling operation will be described. At the time of this cooling operation, the four-way valve 24 of the refrigerant circuit 20 is in the switching state shown by the solid line in FIG. 4, and connects the discharge line 41 to the outdoor heat exchanger 22 and the suction line 42 to the indoor heat exchanger 23. Further, the three-way valve 34 allows the cooling water to flow to the relief pipe 33a at the beginning of the operation of the engine 31, and to the radiator 35 when the temperature of the engine cooling water reaches a predetermined temperature (for example, 60 ° C.). During the cooling operation, the second cooling water outlet 34c of the three-way valve 34 is closed, and the cooling water is not supplied to the auxiliary refrigerant evaporator 28 in principle.
[0048]
During the cooling operation, the solenoid valve 29a of the bypass pipe 29 is always open, so that most of the refrigerant passing through the indoor heat exchanger 23 bypasses the auxiliary refrigerant evaporator 28.
[0049]
Then, the lubricating oil component of the high-pressure refrigerant gas discharged from the refrigerant compressor 21 is first separated by an oil separator (not shown), and the lubricating oil component is returned from the suction line 42 to the accumulator 27. The refrigerant gas from which the lubricating oil component has been removed is supplied to the outdoor heat exchanger 22 through the four-way valve 24. In the outdoor heat exchanger 22, heat is taken from the refrigerant gas and condensed to form a refrigerant liquid. Thereafter, the refrigerant liquid is discharged from the indoor expansion valves 26 (expansion valves provided for each indoor heat exchanger 23), so that the pressure is rapidly reduced and the liquid is sprayed. Is supplied.
[0050]
In the indoor heat exchanger 23, the refrigerant liquid evaporates (evaporates) into a refrigerant gas by evaporating, and the room is cooled by the evaporating action. Most of the refrigerant gas discharged from the indoor heat exchanger 23 flows through the bypass pipe 29 and enters the accumulator 27. After the liquid phase is removed, the refrigerant gas is sucked into the suction part 21b of the refrigerant compressor 21.
[0051]
On the other hand, in the cooling water circuit 30, the cooling water discharged from the cooling water pump 32 is supplied to the engine 31 and cools various parts such as cylinders while passing through a cooling water passage in the engine 31 to increase the temperature. , From the thermostat 33 to the three-way valve 34. In the thermostat 33, when the cooling water temperature is lower than 60 °, the cooling water is sent from the relief pipe 33a to the exhaust gas heat exchanger. Then, the cooling water returns to the cooling water pump 26 after cooling the exhaust gas in the exhaust gas heat exchanger 36.
[0052]
When the temperature of the cooling water becomes 60 ° or more, the relief pipe 33a of the thermostat 33 is closed, the cooling water is sent to the radiator 35 through the three-way valve 34, and the temperature of the cooling water is reduced by the radiator 35. Is returned to the cooling water pump 32.
[0053]
(Heating operation)
Next, the operation during the heating operation will be described. During this heating operation, the four-way valve 24 of the refrigerant circuit 20 is switched to the state shown by the broken line in FIG. 4, and connects the discharge line 41 to the indoor heat exchanger 23 and the suction line 42 to the outdoor heat exchanger 22. Further, the three-way valve 34 allows the cooling water to flow into the relief pipe 33a at the initial stage of the operation of the engine 31, and maintains the first cooling water outlet 34b in a closed state when the temperature of the engine cooling water reaches a predetermined temperature (for example, 60 ° C.). At the same time, the second cooling water outlet 34c is opened to supply the cooling water to the auxiliary refrigerant evaporator 28, and the exhaust heat of the engine is given to the refrigerant, so that the degree of superheat is given to the intake refrigerant, so that the heating capacity can be improved. To
[0054]
During the heating operation, the solenoid valve 29a of the bypass pipe 29 is always closed, and all of the refrigerant that has passed through the outdoor heat exchanger 22 passes through the auxiliary refrigerant evaporator 28.
[0055]
Then, the lubricating oil component of the high-pressure refrigerant gas discharged from the refrigerant compressor 21 is first separated by an oil separator (not shown), and the lubricating oil component is returned from the suction line 42 to the accumulator 27. The refrigerant gas from which the lubricating oil component has been removed is supplied to each indoor heat exchanger 23 through the four-way valve 24. In the indoor heat exchanger 23, the refrigerant gas condenses into a liquid, thereby heating the room. After that, the refrigerant liquid is discharged from the outdoor expansion valve 25, so that the pressure is rapidly reduced and the liquid is sprayed, and is supplied to the outdoor heat exchanger 22.
[0056]
In the outdoor heat exchanger 22, the refrigerant liquid evaporates to change into a refrigerant gas (evaporate) and is discharged from the outdoor heat exchanger 22. The refrigerant gas discharged from the outdoor heat exchanger 22 flows through the auxiliary refrigerant evaporator 28, receives an exhaust heat of the engine in the auxiliary refrigerant evaporator 28, enters an overheated state, enters the accumulator 27, and enters the refrigerant compressor 21. Is sucked into the suction portion 21b.
[0057]
-Explanation of gas engine configuration-
Next, the overall configuration of the gas engine 31 will be described.
[0058]
FIG. 5 is a schematic diagram illustrating a schematic configuration of the entire gas engine according to the present embodiment. As shown in FIG. 5, the present gas engine 31 includes a cylinder block 31b and a cylinder head 31c that constitute an engine body 31a, and an intake system 50 and an exhaust system 60 are connected to the cylinder head 31c, respectively. .
[0059]
First, the intake system 50 will be described. As a configuration of the intake system 50, an intake temperature sensor 52, a mixer 53, and a throttle valve 54 are provided in this order from the upstream side of the intake pipe 51.
[0060]
The intake air temperature sensor 52 detects the temperature of air (outside air) introduced into the intake pipe 51 via an air cleaner (not shown).
[0061]
The mixer 53 mixes the air introduced into the intake pipe 51 with a gas as a fuel (for example, a city gas such as 13 A) to generate an air-fuel mixture having a predetermined air-fuel ratio. The fuel used is not limited to city gas, but various gases such as propane gas can be used.
[0062]
A gas supply pipe 55 is connected to the mixer 53. The gas supply pipe 55 is provided with a zero governor 56 and an air-fuel ratio control valve 57. The zero governor 56 is for maintaining a constant gas pressure on the secondary side downstream of the gas supply pipe 55 irrespective of pressure changes and flow rate changes on the primary side upstream of the gas supply pipe 55. The opening degree of the air-fuel ratio control valve 57 is adjusted by a step motor 58 to adjust the gas supply amount to the mixer 53, thereby adjusting the mixing ratio (air-fuel ratio) of fuel gas and air, and adjusting the air-fuel ratio. The mixture is supplied to the combustion chamber.
[0063]
The throttle valve 54 controls the engine speed and the generated torque by adjusting the intake amount of the air-fuel mixture into the combustion chamber.
[0064]
Next, the exhaust system 60 will be described. As a configuration of the exhaust system 60, a UEGO sensor (entire region air-fuel ratio sensor) 62 and the exhaust gas heat exchanger 36 are provided in this order from the upstream side of the exhaust pipe 61.
[0065]
As described above, the UEGO sensor 62 can measure the excess air ratio in the exhaust gas over a wide range from the lean region to the rich region of the air-fuel mixture, and continuously adjusts the air-fuel ratio of the air-fuel mixture over a wide range. It is a sensor that can be recognized throughout. That is, the UEGO sensor 62 can output a detection signal (current value) corresponding to the oxygen concentration in the exhaust gas. Then, the air-fuel ratio control system according to the present embodiment performs feedback control of the fuel supply amount by adjusting the opening of the air-fuel ratio control valve 57 by a control system described later based on the air-fuel ratio recognized by the UEGO sensor 62. Has become.
[0066]
The exhaust gas heat exchanger 36 is connected to the engine cooling water pipe 30 so as to use the exhaust heat of the engine as a heat source for heating the room to be air-conditioned, and transfers the heat of the exhaust gas through the engine cooling water. This is given to the refrigerant.
[0067]
An engine body 31a configured as a multi-cylinder (for example, three-cylinder) reciprocating engine is provided so as to rotate integrally with a crankshaft (not shown) and a camshaft (not shown). Cam shaft end disks 31e. Electromagnetic pickups 31f and 31g for detecting these rotations are provided.
[0068]
An output shaft of a starter motor 31h is connected to the crankshaft, and rotation (cranking) of the crankshaft is performed by rotational driving of the starter motor 31h.
[0069]
Next, the configuration of the control system of the gas engine will be described. The present gas engine includes a control unit 70 that performs overall engine control. The control unit 70 receives detection signals from the intake air temperature sensor 52, the UEGO sensor 62, and the electromagnetic pickups 31f and 31g. It has become. The control unit 70 receives an engine load signal, a reset signal of a reset switch 82, and the like. Further, the control unit 70 transmits a control signal to the step motor 58 and the cell motor 31h. Upon receiving the control signal, the step motor 58 controls the opening degree of the air-fuel ratio control valve 57 and controls the cell motor 31h. Performs a cranking operation.
[0070]
-Configuration of air-fuel ratio control system-
Next, the configuration of the air-fuel ratio control system will be described. FIG. 6 is a block diagram showing a schematic configuration of the present air-fuel ratio control system. As shown in FIG. 6, the present air-fuel ratio control system includes the control unit 70, the UEGO sensor 62, the λ map 72, and the gain applying unit 73.
[0071]
The control unit 70 includes a signal processing unit 74, a base opening map storage unit 75, an atmospheric calibration value storage unit 79, a calibration value measuring unit 71, and an opening correction signal output unit 77. Each is described below.
[0072]
The signal processing unit 74 receives an output signal (current value) Ip1 from the UEGO sensor 62 and outputs a processing signal Ip2 corresponding to the output signal Ip1. The processed signal Ip2 is converted from the output signal Ip1 so as to be in a signal form that allows a comparison operation process by a comparator 78 described later. Here, when the UEGO sensor 62 changes over time, the output signal Ip1 has a value lower than the output level that should be output (the output level at the time of a new product) according to the degree of the change over time. The gain in the UEGO sensor 62 in the figure indicates a decrease gain when the output level decreases due to the temporal change.
[0073]
The base opening map storage unit 75 receives the signals of the engine speed and the engine load, and determines the basic opening of the air-fuel ratio control valve 57 based on these signals. That is, the output signal from the base opening map storage unit 75 is a signal output based on a table or the like stored in advance to set the air-fuel ratio of the air-fuel mixture to the target value.
[0074]
The atmospheric calibration value storage unit 79 records and updates the calibration value obtained by the atmospheric calibration operation of the UEGO sensor 62 that is periodically executed as described later. In the air-fuel ratio control operation, The calibration value is provided to the gain applying unit 73. That is, based on the calibration value acquired from the atmospheric calibration value storage unit 79, the gain applying unit 73 outputs the temporal change level signal Ip3, and the temporal change level signal Ip3 and the processing signal Ip2 from the signal processing unit 74 are output. Are compared in the comparator 78 to control the air-fuel ratio of the air-fuel mixture.
[0075]
Incidentally, the atmospheric calibration value storage section 79 is constituted by an EEPROM. For this reason, even when the main switch of the GHP is turned off due to a maintenance operation or the like, the above-described calibration value is kept stored. Therefore, when the main switch is turned on and the operation of the engine is restarted, the stored calibration value is stored. The air-fuel ratio control can be accurately performed based on the corrected amount (calibration value). That is, when the main switch is turned on, it is not necessary to execute the atmospheric calibration operation again, and the engine can be restarted quickly.
[0076]
Further, the calibration value measuring section 71 measures the degree of change over time of the UEGO sensor 62 at the time of executing the atmospheric calibration operation. That is, the atmospheric calibration operation is performed by the calibration value measuring unit 71, and the obtained calibration value is input to the atmospheric calibration value storage unit 79, and the calibration value is recorded and updated in the atmospheric calibration value storage unit 79. Go.
[0077]
The opening correction signal output unit 77 outputs an opening correction signal for setting the air-fuel ratio of the air-fuel mixture to a target value. Specifically, the opening degree determined according to a difference between a temporal change level signal Ip3 output through a λ map 72 and a gain applying unit 73 described later and a processing signal Ip2 output from the signal processing unit 74. A correction signal is output. The opening correction amount based on the opening correction signal is added to or subtracted from the output signal (basic opening signal) from the base opening map storage unit 75, thereby opening the air-fuel ratio control valve 57. A signal is obtained.
[0078]
The λ map 72 stores a target value of the excess air ratio, and transmits the target value signal to the gain applying unit 73.
[0079]
The gain applying unit 73 generates a temporal change level signal Ip3 according to the temporal change degree of the UEGO sensor 62, and transmits the signal to the comparator 78. That is, the gain applying unit 73 reads out the time-dependent change characteristic information (calibration value) from the atmospheric calibration value storage unit 79, and thereby obtains a gain equivalent to the gain in the UEGO sensor 62 (gain generated due to time-dependent change). To the target value signal, and this signal is transmitted to the comparator 78. For example, when the excess air ratio in the exhaust pipe 61 has reached the target value (when the air-fuel ratio of the air-fuel mixture matches the target value), the temporal change level signal Ip3 output from the gain applying unit 73 And the level of the output signal IP1 output from the UEGO sensor 62 match.
[0080]
In the comparator 78, the processing signal Ip2 from the signal processing unit 74 is compared with the time-varying level signal Ip3 generated in the gain applying unit 73, and a correction signal corresponding to the difference is output to an opening correction signal output unit. 77.
[0081]
Then, as described above, the output signal (basic opening signal) from the base opening map storage unit 75 based on the opening correction amount based on the opening correction signal from the opening correction signal output unit 77 that has received this correction signal. Is corrected, the opening signal is output to the step motor 58. Accordingly, an opening signal for adjusting the opening of the air-fuel ratio control valve 57 is appropriately obtained, and the air-fuel ratio of the air-fuel mixture is set to the target value.
[0082]
-Explanation of air-fuel ratio control operation-
Hereinafter, the air-fuel ratio control operation of the present air-fuel ratio control system will be described with specific numerical values.
[0083]
Here, when the stoichiometric air-fuel ratio of city gas (about 11: 1) is set to “1”, the target value of the air-fuel ratio is set to “1.6”, that is, the lean burn operation is performed with the target of the air-fuel ratio of about 18: 1. The case where the present air-fuel ratio control system is applied to the engine to be performed will be described.
[0084]
In the following description of the operation, in order to facilitate understanding, the actual air-fuel ratio in the exhaust pipe 61 is a target value of “1.6” when the UEGO sensor 62 is new and has not changed over time. The excess air ratio at this time is represented as "1.6", and the sensor output level at this time is also represented as "1.6". In other words, when the UEGO sensor 62 has changed with time, the sensor output level is "1.4" even if the actual excess air ratio in the exhaust pipe 61 is the target value "1.6". Is low.
[0085]
First, a case in which the UEGO sensor 62 is a new product that has not changed over time will be described. Now, it is assumed that the actual excess air rate in the exhaust pipe 61 is “1.6”. At this time, since the UEGO sensor 62 is new, it is accurately recognized that the sensor output level is “1.6” and the excess air ratio is “1.6”. Then, time-dependent change information (a calibration value corresponding to the information of the point I in FIG. 9) when the UEGO sensor 62 is new is read from the atmospheric calibration value storage unit 79 to the gain applying unit 73. According to the time-varying characteristic information read out here, the time-varying level signal Ip3 output from the gain applying unit 73 becomes “1.6”. That is, there is no difference between the signals (Ip2, Ip3) input to the comparator 78. Therefore, a correction signal of the correction value “0” is transmitted from the comparator 78 to the opening correction signal output unit 77. Therefore, assuming that the current air-fuel ratio matches the target value, the current fuel supply amount is maintained without changing the opening of the air-fuel ratio control valve 57.
[0086]
Next, a case where the UEGO sensor 62 has changed with time will be described. When the UEGO sensor 62 is changing over time, the sensor output level is set to a low value such as “1.4” even though the actual air-fuel ratio in the exhaust pipe 61 is the target value “1.6”. Become. Therefore, the processing signal Ip2 from the signal processing unit 74 also has a level corresponding to this “1.4”. In this case, the temporal change characteristic information (for example, a calibration value corresponding to the information of the point II in FIG. 9) stored in the atmospheric calibration value storage unit 79 by the atmospheric calibration operation described later is read out to the gain applying unit 73. The value of the temporal change characteristic information read out here is “1.4”. That is, according to the aging characteristic information, when the sensor output level of the UEGO sensor 62 is “1.4”, the actual excess air ratio in the exhaust pipe 61 is the target value “1.6”. You. As described above, since the temporal change level signal Ip3 output from the gain applying unit 73 is “1.4”, there is no difference between the signals (Ip2, Ip3) input to the comparator 78 in this case as well. Will be. Accordingly, a correction signal of the correction value “0” is transmitted from the comparator 78 to the opening correction signal output unit 77. Therefore, assuming that the current air-fuel ratio matches the target value, the current fuel supply amount is maintained without changing the opening of the air-fuel ratio control valve 57.
[0087]
Next, an operation when the UEGO sensor 62 has changed over time and the current air-fuel ratio deviates from the target value will be described. Here, as described above, when the actual excess air ratio in the exhaust pipe 61 is the target value “1.6”, a temporal change occurs in which the sensor output level of the UEGO sensor 62 becomes “1.4”. , The air-fuel ratio control operation in a situation where the sensor output level of the UEGO sensor 62 is “1.5” because the actual excess air ratio in the exhaust pipe 61 deviates from the target value I do.
[0088]
In the situation where the sensor output level of the UEGO sensor 62 is “1.5”, the processing signal Ip2 from the signal processing unit 74 also has a level corresponding to “1.5”. At this time, the temporal change characteristic information stored in the atmospheric calibration value storage unit 79 by the atmospheric calibration operation is read out to the gain applying unit 73. The value of the temporal change characteristic information read out here is “1.4”. That is, when the actual excess air ratio in the exhaust pipe 61 is the target value “1.6”, information indicating that the sensor output level of the UEGO sensor 62 should be “1.4” is read. Therefore, there is a difference between the signals (Ip2, Ip3) input to the comparator 78, and the sensor output level of the UEGO sensor 62 is higher by “0.1”. Originally, when the actual excess air ratio in the exhaust pipe 61 is the target value “1.6”, the sensor output level of the UEGO sensor 62 should be “1.4”. .5 "indicates that the excess air ratio is too high. In this case, a correction signal of the correction value “−0.1” is transmitted from the comparator 78 to the opening correction signal output unit 77. Therefore, the output signal (basic opening signal) from the base opening map storage unit 75 is corrected (subtracted by the 0.1 minute) with the opening correction amount of the correction value “−0.1”. Thus, an opening signal of the air-fuel ratio control valve 57 is obtained. In this case, the opening degree of the air-fuel ratio control valve 57 is increased to increase the fuel supply amount in order to reduce the excess air ratio by the amount corresponding to the above “0.1”.
[0089]
As described above, in the present embodiment, the air calibration of the UEGO sensor 62 is performed, and the opening degree signal of the air-fuel ratio control valve 57 is recognized while recognizing how much the output level of the UEGO sensor 62 has decreased with time. Can be obtained appropriately. For this reason, highly accurate air-fuel ratio control can be stably maintained over a long period of time.
[0090]
-Operation description at engine restart-
Before describing the atmospheric calibration operation, an operation at the time of restart of the engine 31 after stopping in the GHP will be described.
[0091]
After the engine 31 is stopped due to the thermo-OFF of all the indoor units during the operation of the GHP or the stop of the operation of all the indoor units (a user's OFF operation using a remote controller or the like), the engine 31 and the refrigerant compressor 21 are stopped. Restart is prohibited for 3 minutes to protect the system. After the elapse of the standby time (3 minutes), the restart of the engine 31 is permitted, and the GHP is restarted by an operation request of any of the indoor units (a user's ON operation using a remote controller or the like). Is started.
[0092]
In this restart operation, first, a preliminary operation for driving the outdoor fans 15, 15, the ventilation fan 7, and the cooling water pump 32 provided in the outdoor unit is performed. This operation includes a heat exchange operation in the outdoor unit heat exchanger 22 when the refrigerant circulation of the refrigerant circuit 20 is started with the start of the engine 31, and an external air temperature sensing operation by an external air temperature sensor provided in the ventilation port. This is a preliminary operation operation for smoothly performing the cooling operation by the engine cooling water. Thus, the preliminary operation is started, and after the preliminary operation is continued for 5 seconds, the fuel supply system and the ignition system of the engine 31 are activated to start the engine. The above is the operation at the time of restarting the engine 31 after stopping in the GHP.
[0093]
−Explanation of atmospheric calibration operation−
Next, the atmospheric calibration operation of the UEGO sensor 62, which is an operation characteristic of the present embodiment, will be specifically described.
[0094]
The atmospheric calibration is started when all the indoor units are turned off after 450 hours have passed since the previous atmospheric calibration. Further, in this embodiment, after 450 hours have passed since the previous atmospheric calibration, the state where all the indoor units are thermo-OFF does not occur, and when 500 hours have passed since the previous atmospheric calibration, the outdoor unit Is forcibly stopped, and then the atmospheric calibration is started.
[0095]
Normally, when all the indoor units are thermo-OFF (when all the indoor units are thermo-OFF in a state where 450 hours have not elapsed since the previous atmospheric calibration), the UEGO sensor 62 is activated. However, at this time (when all the indoor units are turned off after 450 hours have passed since the last atmospheric calibration), the power supply to the heater is still ON. The state is maintained so that the UEGO sensor 62 can detect the oxygen concentration.
[0096]
FIG. 7 shows a timing chart when the atmospheric calibration operation is performed. The timing chart includes, in order from the top, the system operation timing (switching timing of the operation / stop of the engine 31), the outdoor fans 15, 15, the ventilation fan 7, the drive timing of the cooling water pump 32, and the starter (the clock at the time of the atmospheric calibration operation). Ranking) indicates the execution timing.
[0097]
Now, during the engine operation, when the accumulated operation time reaches the execution timing of the atmospheric calibration operation (450 hours have elapsed since the previous atmospheric calibration), the atmospheric calibration FG becomes “1”. Thereafter, all the indoor units are turned off and the outdoor units are stopped, or 500 hours have passed since the previous atmospheric calibration (50 hours have passed since the atmospheric calibration FG became "1"). In the situation where the outdoor unit is forcibly stopped, the operation shifts to the atmospheric calibration operation.
[0098]
In this atmospheric calibration operation, first, the warning means 76 provided in the control unit 70 is operated, and the execution of the atmospheric calibration is prohibited for a time A (for example, three minutes) in the figure from the stop of the outdoor unit. Then, after the execution prohibition time (3 minutes) has elapsed, a command from the warning means 76 is issued for a preliminary operation for driving the outdoor fans 15, 15, the ventilation fan 7 and the cooling water pump 32 provided in the outdoor unit together. Perform based on signals. After a lapse of 5 seconds from the start of the preliminary operation in this way, the engine 31 is cranked while the air-fuel ratio control valve 57 is kept fully closed, and the atmospheric calibration operation of the UEGO sensor 62 is executed.
[0099]
Specifically, the calibration value measurement unit 71 causes the engine to execute the following operation when executing the atmospheric calibration operation. That is, in a state where the step motor 58 is driven to completely close the air-fuel ratio control valve 57 and the fuel supply is prohibited, the cell motor 31h is energized to perform the cranking operation of the engine. As a result, the atmosphere is introduced into the exhaust pipe 61 and the atmosphere calibration operation is performed.
[0100]
More specifically, the atmospheric calibration operation is executed by intermittently executing the cranking operation of the engine a plurality of times and causing the UEGO sensor 62 to perform the sensing operation at the end of the final cranking operation. For example, as shown in FIG. 7, the cranking of 10 sec per time is intermittently performed three times (at intervals of 5 sec), and the UEGO sensor 62 is turned off at the end of the third cranking operation. The atmospheric calibration operation is performed by performing the sensing operation.
[0101]
FIG. 8 shows how the output level of the UEGO sensor 62 changes during the cranking operation. At the end of the third cranking operation, the output level of the UEGO sensor 62 is in a substantially stable state, and it can be seen that the exhaust pipe 61 is filled with the atmosphere. By recognizing the sensor output level at this time, the degree of the temporal change of the UEGO sensor 62 at the present time can be measured. That is, the degree of change over time of the UEGO sensor 62 can be measured by comparing the sensor output level at this time with the sensor output level when the UEGO sensor 62 is new.
[0102]
As described above, in the present embodiment, the atmosphere is introduced into the exhaust pipe 61 by the cranking operation of the engine to perform the air calibration operation. Therefore, a special means for placing the UEGO sensor 62 in the air atmosphere. Is not required. That is, a special introduction path for introducing outside air into the exhaust pipe 61, valve means for opening and closing the introduction path and a drive source thereof, a blower for introducing air into the introduction path, and the like are provided. It is not necessary to provide the atmospheric pressure sending means, and the UEGO sensor 62 can be exposed to the atmosphere by means existing in the engine. For this reason, the air calibration operation can be realized without inviting a large increase in the number of parts and an increase in the size of the air-fuel ratio control system, and the practicality of the air-fuel ratio control system can be improved.
[0103]
Further, when the atmospheric calibration operation is performed by the cranking operation as described above, in order to exhaust all the exhaust gas in the exhaust pipe 61 and fill the exhaust pipe 61 with the atmosphere, it is necessary to configure the exhaust system and the gas engine. Although it depends on the size and the like, a cranking operation of about 30 seconds is generally required. At this time, if the cell motor 31h is driven continuously for 30 seconds, the load applied to the cell motor 31h becomes excessively large, and there is a possibility that the cell motor 31h may be burned and the durability may be impaired.
[0104]
Therefore, in the present embodiment, the cranking operation is intermittently executed a plurality of times as described above, and the atmospheric calibration operation is executed at the end of the final cranking operation. According to this, it is possible to avoid a situation in which the cell motor 31h is continuously energized for a long time, and it is possible to maintain a longer life. As described above, when the cranking of 10 sec per time is intermittently performed three times, the load applied to the starter motor 31h can be greatly reduced as compared with the case where the cranking is continuously performed for 30 seconds. The inside of the exhaust pipe 61 can be sufficiently filled with the atmosphere. The cranking time and the number of times of cranking are not limited to the above, and can be arbitrarily set, such as intermittently performing cranking of 6 sec for 5 times.
[0105]
-Effects of Embodiment-
As described above, in the present embodiment, when the atmospheric calibration of the UEGO sensor 62 is performed, the same preliminary operation as the normal restart of the engine 31 is performed. For example, if there is an operator performing maintenance work without knowing that the GHP has the atmospheric calibration function of the UEGO sensor 62, if a preliminary operation similar to a normal engine start is performed during this maintenance work, The worker recognizes that the engine is started by hearing the wind noise and the motor sound of the fans 15 and 7 and the motor sound of the cooling water pump 32, and performs the maintenance work by stopping or beware of the maintenance work. . For this reason, it is possible to prevent the maintenance operator from being surprised by the careless operation of the atmosphere.
[0106]
Further, in this embodiment, when 450 hours have elapsed since the previous atmospheric calibration, all the indoor units are thermo-offed, or the state in which all the indoor units are thermo-offed does not occur from the previous atmospheric calibration. When 500 hours have passed, the outdoor unit is forcibly stopped, and then the atmospheric calibration is started. Thereby, the atmospheric calibration can be performed at a timing when the possibility that the maintenance work is performed is low.
[0107]
-Other embodiments-
In the above-described embodiment, a case has been described in which the present invention is applied to the GHP engine cooling water circuit 30 in which the gas engine 31 drives the refrigerant compressor 21 as the engine-driven heat pump. The present invention is not limited to this, and can be applied to an engine cooling water circuit of an engine driven heat pump using other gas fuel or an engine driven heat pump using liquid fuel such as kerosene.
[0108]
Further, in the above-described embodiment, all the indoor units are turned off after 450 hours have passed since the previous atmospheric calibration, or all the indoor units are turned off after 450 hours have passed from the previous atmospheric calibration. When 500 hours have elapsed since the previous calibration of the atmosphere without causing a state to be performed, the calibration of the atmosphere of the UEGO sensor 62 is performed, and the preliminary operation is performed before the execution of the calibration of the atmosphere. The present invention is not limited to this. When the atmospheric calibration is performed at the above timing, there is almost no possibility that the maintenance worker is present near the unit using the heat pump at the start of the atmospheric calibration. Alternatively, after the engine 31 is stopped, the engine 31 may be immediately cranked to perform the atmospheric calibration.
[0109]
Further, in the above-described warning operation, all of the outdoor fan 15, the ventilation fan 7, and the cooling water pump 32 are driven, but any one or two of them may be driven. Also, an alarm buzzer may be provided so that the alarm buzzer sounds before the execution of the atmospheric calibration. Further, a warning operation may be performed to the visual sense of the maintenance worker. For example, in addition to driving the outdoor fan 15 as described above, a display unit (such as a liquid crystal display unit) is provided on the operation panel of the outdoor unit. The execution of the atmospheric calibration may be displayed on the display unit in advance.
[0110]
【The invention's effect】
As described above, in the present invention, when calibrating the air in the entire region air-fuel ratio sensor provided in the exhaust system of the engine-driven heat pump, the maintenance worker is advised that the air calibration is performed immediately before the start of the air calibration. By warning the auditory and visual senses, the worker can be alerted during maintenance work. In addition, the atmospheric calibration is performed at a timing when the possibility that the maintenance work is performed is low or when the maintenance worker expects that the engine may be started. As a result, it is possible to prevent the air calibration operation from being performed carelessly during the maintenance work (an operation unexpected by the maintenance operator is performed). The practicality of the drive heat pump can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an internal configuration of a GHP outdoor unit according to an embodiment.
FIG. 2 is a front view showing an internal configuration of the GHP outdoor unit according to the embodiment.
FIG. 3 is a plan view showing an internal configuration of the GHP outdoor unit according to the embodiment.
FIG. 4 is a circuit diagram showing a GHP refrigerant circuit and an engine cooling water circuit.
FIG. 5 is a schematic diagram showing a schematic configuration of the entire gas engine.
FIG. 6 is a block diagram illustrating a schematic configuration of an air-fuel ratio control system.
FIG. 7 is a diagram showing a timing chart when an atmospheric calibration operation is performed.
FIG. 8 is a diagram showing the relationship between the number of crankings and the output level of a UEGO sensor.
FIG. 9 is a diagram for explaining a time-dependent change characteristic of the UEGO sensor.
FIG. 10 is a diagram showing a relationship between an excess air ratio and a sensor output of a UEGO sensor.
[Explanation of symbols]
7 Ventilation fan
15 Outdoor fan
31 engine
32 Cooling water pump
60 Exhaust system
62 UEGO sensor (all area air-fuel ratio sensor)
76 Warning Means

Claims (4)

In an engine-driven heat pump using an engine having a full-range air-fuel ratio sensor in the exhaust system as a drive source,
Immediately before performing the air calibration for introducing the atmosphere into the exhaust system and performing the sensing operation of the entire area air-fuel ratio sensor, a warning unit for performing a warning operation for warning that the air calibration is performed is provided. An engine-driven heat pump equipped with a full-range air-fuel ratio sensor. An engine-driven heat pump comprising the full-range air-fuel ratio sensor according to claim 1,
After the engine is stopped, the restart is prohibited for a predetermined time, and at the time of the restart, at least one of the outdoor fan, the ventilation fan, and the cooling water pump provided in the heat pump heat source side unit is provided. While the engine is started after one performs a preliminary operation in which it is driven for a predetermined time,
When performing the atmospheric calibration of the full-range air-fuel ratio sensor, the warning unit performs the preliminary operation after a time substantially equal to the predetermined time has elapsed after the engine is stopped, and then the atmospheric calibration is started. An engine-driven heat pump provided with a full-range air-fuel ratio sensor. In an engine-driven heat pump that uses an engine having an exhaust gas air-fuel ratio sensor in the exhaust system as a drive source and circulates a heat medium between the heat pump heat source side unit and the heat pump user side unit in response to a request from the heat pump user side unit,
The whole-area air-fuel ratio is characterized in that the air calibration that performs the sensing operation of the entire-area air-fuel ratio sensor by introducing the atmosphere into the exhaust system is performed while all of the units on the heat pump utilization side are in the thermo-off stop state. Engine driven heat pump with sensor. In an engine-driven heat pump that uses an engine having an exhaust gas air-fuel ratio sensor in the exhaust system as a drive source and circulates a heat medium between the heat pump heat source side unit and the heat pump user side unit in response to a request from the heat pump user side unit,
Atmospheric calibration, in which the atmosphere is introduced into the exhaust system and the sensing operation of the entire area air-fuel ratio sensor is performed, is performed when the heat pump heat source side unit is forcibly stopped when there is a heat medium circulation request from the heat pump utilization side unit. An engine-driven heat pump including a full range air-fuel ratio sensor configured to execute.

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