JP2007146676A - Cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cogeneration system for restraining the deterioration in engine oil, by restraining overheating of an engine, by lowering the temperature of cooling water supplied to the engine in ordinary operation, by solving the problem of requiring time for warming up the engine. <P>SOLUTION: This system has the engine 1 driving an electric motor 2, an exhaust gas heat exchanger 3 passing exhaust gas exhausted from the engine 1, a pump 4 supplying the cooling water to the engine 1 and the exhaust gas heat exchanger 3, and a hot water heat exchanger 5 passing the cooling water heated by passing through both the engine 1 and the exhaust gas heat exchanger 3. By a control part 8, a selector valve 6 switches a first passage performing warming-up operation for passing the cooling water in order of the exhaust gas heat exchanger 3 and the engine 1 and a second passage performing the ordinary operation for passing the cooling water in order of the engine 1 and the exhaust gas heat exchanger 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cogeneration system that extracts power output from a generator and hot water output from a hot water heat exchanger.

  Patent Document 1 discloses a cogeneration system in which cooling water flows in the order of gas engine → exhaust gas heat exchanger → hot water heat exchanger → engine as an exhaust heat recovery circuit.

In Patent Document 2, as the exhaust heat recovery circuit, an exhaust gas heat exchanger is not provided in the engine cooling circuit, but an exhaust gas heat exchanger is provided in the secondary (warm water output side) circuit so that a higher temperature can be obtained. An engine exhaust heat system including a circuit for directly heating secondary hot water with exhaust gas and a control method thereof are disclosed.
JP-A-8-4586 JP 2000-274307 A

  In Patent Document 1, as described above, since the cooling water flows in the order of the gas engine → the exhaust gas heat exchanger → the hot water heat exchanger, the cooling water that radiates heat in the hot water heat exchanger and decreases in temperature flows to the engine. become. For this reason, at the time of starting the engine, the cooling water that is not so warm passes through the engine. For this reason, there is a problem that it takes time to warm up after the engine is started. For example, in a cogeneration system installed in a store or the like, engine operation, engine stop, and engine restart may be performed several times a day depending on the activity status of the store. Thus, when the engine is restarted a plurality of times, it is not preferable that the engine warm-up operation takes time.

  The same applies to Patent Document 2, and the cooling water discharged from the pump first flows to the gas engine. For this reason, at the time of starting the engine, the cooling water that is not so warm passes through the engine. Therefore, there is a problem that it takes time to warm up the engine after the engine is started.

  The present invention has been made in view of the above circumstances, and can solve the problem that it takes time to warm up after starting the engine. Further, the temperature of cooling water supplied to the engine during normal operation after warming up the engine is improved. It is an object of the present invention to provide a cogeneration system that can reduce the engine temperature, suppress engine overheating, and suppress deterioration of engine oil and the like.

(1) A cogeneration system according to aspect 1 supplies an engine, a generator driven by the engine, an exhaust gas heat exchanger through which exhaust gas discharged from the engine passes, and cooling water to the engine and the exhaust gas heat exchanger. Cooling water transport means, and a hot water heat exchanger through which the heated cooling water passes through both the engine and the exhaust gas heat exchanger. The power output from the generator and the hot water heat exchanger In a cogeneration system that takes out hot water output,
It is possible to switch between a first path for executing a warm-up operation in which cooling water is passed in the order of the exhaust gas heat exchanger and the engine and a second path for executing a normal operation in which cooling water is passed in the order of the engine and the exhaust gas heat exchanger. Switching means;
When the engine operation is determined to be warm-up operation, the switching means is controlled to select the first route, and when the engine operation is determined to be normal operation, the second route is selected. And a control unit for controlling the means.

  When it is determined that the engine operation is a warm-up operation, the control unit controls the switching unit to select the first route. As a result, the cooling water passes through the exhaust gas heat exchanger and the engine in this order. For this reason, at the time of warm-up operation, the cooling water warmed by the exhaust gas heat exchanger flows through the engine, so that the engine can be warmed up quickly and the start-up of the engine can be accelerated.

  On the other hand, when it is determined that the engine operation is the normal operation after the warm-up operation, the control unit controls the switching unit to select the second route. As a result, the cooling water is passed through the engine and the exhaust gas heat exchanger in this order. For this reason, during normal operation after warm-up operation, cooling water that has not been heated by the exhaust gas heat exchanger flows through the engine, so that the engine can be cooled efficiently, overheating of the engine can be prevented, and heat deterioration of the engine oil can be prevented. Can be suppressed. Furthermore, since the cooling water heated by the engine can be further heated by the exhaust gas heat exchanger, the temperature of the cooling water supplied to the hot water heat exchanger can be made as high as possible. Therefore, the hot water output taken out from the hot water heat exchanger can be made as high as possible, which is advantageous as a cogeneration system.

  The warm-up operation means an operation in a starting region where the engine temperature is equal to or lower than a certain temperature from the time when the engine is started. The normal operation means an operation when the engine exceeds a certain temperature after the warm-up operation. The constant temperature that distinguishes between the warm-up operation and the normal operation is determined directly or indirectly based on the temperature of the coolant flowing through the engine coolant passage, the temperature of the engine oil, and the like. The constant temperature is basically determined according to the type of engine.

Specifically, the determination of whether the engine operation is a warm-up operation or a normal operation can be made by, for example, the following (a) to (c).
(A) When the temperature of the cooling water flowing inside the engine is low, it is determined that the engine is warming up. When the temperature of the cooling water is high, it is determined that the engine is operating normally. In this case, it is preferable to provide a cooling water temperature detecting means for detecting the temperature of the cooling water flowing through the engine cooling water passage (for example, the outlet or the inlet of the engine cooling water passage).
(B) When engine oil is used for the engine, it is determined that the engine is warm-up when the temperature of the engine oil is low, and is determined as normal operation when the temperature of the engine oil is high. In this case, it is preferable to provide an engine oil temperature detecting means for detecting the temperature of the engine oil.
(C) When the elapsed time from the time when the engine is started is less than or equal to a predetermined time, it is determined that the engine is warming up, and when the elapsed time exceeds the predetermined time, it is determined that the engine is operating normally. In this case, it is preferable to provide an outside temperature detecting means for detecting the temperature of the outside air and consider the outside air temperature. For example, when the outside air temperature is low, the predetermined time for determining the warm-up operation is lengthened. When the outside air temperature is high, the predetermined time for determining the warm-up operation is shortened.

  (2) According to the cogeneration system according to aspect 2, the heat dissipation radiator is provided, and when it is determined that the temperature of the cooling water flowing through the hot water heat exchanger has become higher than a predetermined temperature, the cooling water is supplied to the heat dissipation radiator. There is provided a valve for switching the passage of the cooling water so that the heat is radiated from the heat radiating radiator. When it is determined that the temperature of the cooling water is higher than the predetermined temperature, the cooling water is presumed to be overheated, and therefore the cooling water is cooled by the heat radiating radiator. Thereby, overheating of cooling water is prevented, and overheating of the engine is prevented.

  (3) The cogeneration system according to aspect 3 has the first port, the second port, the third port, and the fourth port of the switching means. Here, the first port functions as a suction port for sucking the cooling water supplied from the cooling water transfer means in both the warm-up operation and the normal operation. The second port functions as a discharge port that discharges cooling water into the cooling water passage of the exhaust gas heat exchanger during warm-up operation, and as a suction port that sucks cooling water from the cooling water passage of the exhaust gas heat exchanger during normal operation. Function. The third port of the switching means functions as a suction port that sucks cooling water from the cooling water passage of the engine in the warm-up operation, and functions as a discharge port that discharges cooling water to the cooling water passage of the engine in the normal operation. The fourth port of the switching unit functions as a discharge port that discharges the cooling water to the cooling water passage of the hot water heat exchanger in both the warm-up operation and the normal operation. In this way, only one switching means is required, which is advantageous for cost reduction and prevention of enlargement.

  According to the cogeneration system according to the present invention, after the engine is started, the cooling water passes in the order of the exhaust gas heat exchanger → the engine. Accordingly, during warm-up operation, the cooling water warmed by the exhaust gas heat exchanger flows through the engine. For this reason, the warm-up of the engine can be accelerated and the start-up of the engine can be accelerated.

  Further, during normal operation after the engine is warmed up, the cooling water passes in the order of engine → exhaust gas heat exchanger. Thus, during normal operation, cooling water that is not heated by the exhaust gas heat exchanger is supplied to the engine. For this reason, the temperature of the cooling water supplied to the engine can be lowered, overheating of the engine can be suppressed, and a cogeneration system advantageous for suppressing deterioration of engine oil and the like can be provided.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to FIGS. As schematically shown in FIG. 1, the cogeneration system includes an engine 1 formed by a gas engine, a generator 2, an exhaust gas heat exchanger 3 for recovering exhaust heat of the engine 1, and a cooling water transfer means. The pump 4 which functions, the hot water heat exchanger 5, the switching valve 6 which functions as a switching means, the channel | path 7 which connected these, and the control part 8 which controls the switching valve 6 are provided.

  The engine 1 is driven by the combustion of fuel gas supplied from the fuel supply path 1a. The engine 1 has a cooling water passage 1w through which cooling water flows. The generator 2 is rotationally driven by the rotation of the drive shaft 1m of the engine 1 to generate electric power. Electric power is taken out via the power converter 20 (inverter). The exhaust gas heat exchanger 3 includes a cooling water passage 3w through which cooling water conveyed by the pump 4 flows, and an exhaust gas passage 3k through which exhaust gas discharged from the exhaust port 1r of the engine 1 passes. In the exhaust gas heat exchanger 3, the exhaust gas flowing through the exhaust gas passage 3k and the cooling water flowing through the cooling water passage 3w exchange heat. For this reason, the exhaust gas flowing through the exhaust gas passage 3k is cooled, and the cooling water flowing through the cooling water passage 3w is heated.

  The pump 4 supplies cooling water to the cooling water passage 1 w of the engine 1 and the cooling water passage 3 w of the exhaust gas heat exchanger 3. The hot water heat exchanger 5 has a cooling water passage 5w through which the heated cooling water passes through both the engine 1 and the exhaust gas heat exchanger 3, and a water passage 5k through which the heated water passes. In the hot water heat exchanger 5, the cooling water flowing through the cooling water passage 5w and the water from which the output of the hot water flowing through the water passage 5k is extracted exchange heat. For this reason, the cooling water flowing through the cooling water passage 5w of the hot water heat exchanger 5 is cooled, the water flowing through the water passage 5k is heated, and the exhaust heat of the engine 1 is taken out as a hot water output.

  The hot water heat exchanger 5 is connected to the hot water storage system 55. The hot water storage system 55 stores heat by exchanging heat with the hot water heat exchanger 5, and includes a hot water forward path 55a connected to the inlet of the water passage 5k, a hot water return path 55b connected to the outlet of the water passage 5k, and a hot water forward path 55a. And a conveyance pump 55c that circulates and conveys water to the hot water return path 55b, and a hot water storage tank 55d that stores the hot water heat-exchanged by the hot water heat exchanger 5. Therefore, when the transport pump 55c is driven, the exhaust heat of the engine 1 is recovered as hot water in the hot water storage tank 55d via the hot water heat exchanger 5.

  The switching valve 6 is a 4-port valve, and has a first port 61, a second port 62, a third port 63, and a fourth port 64. The first port 61 of the switching valve 6 is located downstream of the pump 4 and always communicates with the discharge port 4c of the pump 4 via the passage 7a. Therefore, the first port 61 of the switching valve 6 functions as a suction port for sucking the cooling water supplied from the pump 4 to the switching valve 6 in both the warm-up operation and the normal operation.

  The second port 62 of the switching valve 6 always communicates with the port 3x of the cooling water passage 3w of the exhaust gas heat exchanger 3 via the passage 7b. Accordingly, the second port 62 of the switching valve 6 functions as a discharge port for discharging cooling water to the port 3x of the cooling water passage 3w of the exhaust gas heat exchanger 3 in the warm-up operation, but in the normal operation, the exhaust gas heat exchanger 3 The cooling water passage 3w is switched from the port 3x to the suction port for sucking the cooling water.

  The third port 63 of the switching valve 6 always communicates with the port 3y of the coolant passage 1w of the engine 1 via the passage 7c. Accordingly, the third port 63 of the switching valve 6 functions as a suction port for sucking cooling water from the port 1y of the cooling water passage 1w of the engine 1 in the warm-up operation, but is a port of the cooling water passage 1w of the engine 1 in the normal operation. It is switched to a discharge port that discharges cooling water in 1y.

  The fourth port 64 of the switching valve 6 is located upstream of the hot water heat exchanger 5 and always communicates with the inlet 5i of the cooling water passage 5w of the hot water heat exchanger 5 through the passage 7d. Therefore, the fourth port 64 of the switching valve 6 functions as a discharge port that discharges the cooling water to the inlet 5i of the cooling water passage 5w of the hot water heat exchanger 5 in both the warm-up operation and the normal operation.

  The passage 7 through which the cooling water flows has a heat radiating radiator 9 (heat radiating element) having a radiator fan 90, and a first valve 100 and a second valve 200 (cooling water passage switching element). The heat radiation radiator 9 communicates with the outlet 5o of the cooling water passage 5w of the hot water heat exchanger 5. As described below, the first valve 100 and the second valve 200 allow the cooling water to flow to the bypass passage 7f, but do not flow the cooling water to both the radiator 9 and the hot water heat exchanger 5 and the cooling water. A mode (ii) that flows to the hot water heat exchanger 5 but does not flow to the heat radiator 9 and a mode (iii) that flows cooling water to both the hot water heat exchanger 5 and the heat radiator 9 are switched.

  Therefore, the passage 7 bypasses both the heat radiation radiator 9 and the hot water heat exchanger 5 to bypass the cooling water and does not flow to both, and the passage 7 flows the cooling water to the hot water heat exchanger 5, but the heat radiation radiator 9 Has a passage 7h that does not flow, and a passage 7i that allows cooling water to flow to both the hot water heat exchanger 5 and the radiator 9.

  FIG. 1 shows a first path for executing the warm-up operation. In the warm-up operation, as shown in FIG. 1, the cooling water is passed in the order of the cooling water passage 3 w of the exhaust gas heat exchanger 3 → the cooling water passage 1 w of the engine 1. FIG. 2 shows a second path for executing normal operation after warm-up. In the normal operation, as shown in FIG. 2, the cooling water is passed in the order of the cooling water passage 1 w of the engine 1 → the cooling water passage 3 w of the exhaust gas heat exchanger 3.

  By the control unit 8, the switching valve 6 switches between a first path for executing the warm-up operation and a second path for executing the normal operation according to the state of the engine 1. The first valve 100 and the second valve 200 switch the flow of the cooling water in the passage 7 in response to the temperature of the cooling water. That is, the first valve 100 has the first opening 101, the second opening 102, and the third opening 103, and switches the communication of the first opening 101, the second opening 102, and the third opening 103 by melting or deforming the wax. To switch the passage 7. The second valve 200 has a first opening 201, a second opening 202, and a third opening 203, and switches the communication of the first opening 201, the second opening 202, and the third opening 203 by melting or deforming the wax, and a passage. 7 is switched.

  Specifically, the 1st valve 100 and the 2nd valve 200 are set like the following form (i), form (ii), and form (iii).

  Form (i): When the temperature of the cooling water is low, such as when the engine 1 is started, the first opening 101 and the second opening 102 of the first valve 100 are opened and communicated, but the third opening 103 is closed. Is done. For this reason, although the cooling water flows through the bypass passage 7 f, it does not flow into both the hot water heat exchanger 5 and the radiator radiator 9. Therefore, it is prevented that the temperature of the cooling water flowing through the passage 7 is too cold. For this reason, low-temperature cooling water is prevented from flowing into the engine 1, and startability of the engine 1 is ensured.

  Form (ii): When the temperature of the cooling water rises, the communication of the first opening 101 and the second opening 102 of the first valve 100 is slightly reduced, but the third opening 103 is slightly opened. Further, the first opening 201 and the second opening 202 of the second valve 200 are opened and communicated, but the third opening 203 of the second valve 200 is closed. In this case, the cooling water flows to the bypass passage 7f, the hot water heat exchanger 5 and the passage 7h. However, since the third opening 203 of the second valve 200 is closed, the cooling water does not flow through the heat radiating radiator 9 and the passage 7i. Thus, since it does not flow to the heat dissipation radiator 9, excessive cooling of the cooling water is prevented. When the temperature of the cooling water further rises, the second opening 102 of the first valve 100 is closed, so that the cooling water does not flow into the bypass passage 7f. This is because the amount of cooling water flowing through the hot water heat exchanger 5 is increased to take in as much hot water output as possible in the hot water heat exchanger 5 to increase the efficiency of energy intake from the hot water.

  Form (iii): When the temperature of the cooling water further rises and becomes considerably high, in the first valve 100, the first opening 101 is opened, the second opening 102 is closed, and the third opening 103 is opened. Further, the first opening 201 and the third opening 203 of the second valve 200 are opened, and the second opening 202 is closed. For this reason, the cooling water flows through the hot water heat exchanger 5 and the passage 7h, the heat radiator 9 and the passage 7i. In this case, after flowing through the cooling water passage 5 w of the hot water heat exchanger 5, it flows through the heat dissipation radiator 9. The reason is to take in as much hot water output as possible in the hot water heat exchanger 5.

  The temperature Twe for the engine 1 is used. The temperature Twe is detected by a temperature sensor 1s that functions as a temperature detection unit mounted on the engine 1. In the drawing, the mounting location of the temperature sensor 1s is schematically shown. The temperature Twe is the temperature of the cooling water on the outlet side of the cooling water passage 1 w of the engine 1 or the temperature of the oil in the oil passage of the engine 1. A signal related to the temperature Twe is input to the control unit 8 through the signal line 8f. The control unit 8 determines the state of the engine 1 based on the temperature Twe, and outputs the control signal to the switching valve 6 via the signal line 8s.

  When the control unit 8 determines that the temperature Twe is lower than the first predetermined temperature T1, the control unit 8 controls the switching valve 6 so as to select the first path for executing the warm-up operation. In the warm-up operation, as shown in FIG. 1, the first port 61 and the second port 62 of the switching valve 6 communicate with each other, and the third port 63 and the fourth port 64 of the switching valve 6 communicate with each other. When the pump 4 is driven, the cooling water is supplied from the pump 4 → the passage 7a → the first port 61 of the switching valve 6 → the second port 62 of the switching valve 6 → the passage 7b → the port 3x of the exhaust gas heat exchanger 3 → exhaust gas heat. Cooling water passage 3w of exchanger 3 → port 3y of exhaust gas heat exchanger 3 → port 1x of engine 1 → cooling water passage 1w of engine 1 → port 1y of engine 1 → passage 7c → third port 63 of switching valve 6 → It flows in the order of the fourth port 64 of the switching valve 6 → the passage 7 d → the hot water heat exchanger 5.

  Thus, in the warm-up operation of the engine 1, the cooling water flows in the order of the cooling water passage 3 w of the exhaust gas heat exchanger 3 → the cooling water passage 1 w of the engine 1, so that the cooling water heated by the exhaust gas heat exchanger 3. Will flow through the engine 1. For this reason, the warm-up operation of the engine 1 can be accelerated by using the exhaust heat of the exhaust gas of the engine 1, and the start-up of the engine 1 can be accelerated. Even in the warm-up operation, the temperature of the exhaust gas discharged from the engine 1 is quite high, and the cooling water flowing through the cooling water passage 3w of the exhaust gas heat exchanger 3 can be considerably warmed.

  Here, in the warm-up operation, immediately after the engine 1 is started, the temperature Twe is equal to or lower than the first predetermined temperature T1. For this reason, the 1st valve 100 and the 2nd valve 200 become the above-mentioned form (i), and cooling water does not flow into warm water heat exchanger 5 and radiator radiator 9. As a result, excessive cooling of the cooling water in the warm-up operation is prevented, which is advantageous for speeding up the warm-up operation of the engine 1.

  On the other hand, when the warm-up operation of the engine 1 is finished and the normal operation of the engine 1 is shifted, the temperature Twe rises. In this case, when the control unit 8 determines that the temperature Twe is higher than the first predetermined temperature T1, the control unit 8 controls the switching valve 6 so as to select the second path for executing the normal operation. In normal operation, as shown in FIG. 2, the first port 61 and the third port 63 of the switching valve 6 communicate with each other, and the second port 62 and the fourth port 64 of the switching valve 6 communicate with each other. When the pump 4 is driven, the cooling water is pump 4 → the passage 7a → the first port 61 of the switching valve 6 → the third port 63 of the switching valve 6 → the passage 7c → the port 1y of the engine 1 → the cooling water of the engine 1. Passage 1w → port 1x of engine 1 → port 3y of exhaust gas heat exchanger 3 → cooling water passage 3w of exhaust gas heat exchanger 3 → port 3x of exhaust gas heat exchanger 3 → passage 7b → second port 62 of switching valve 6 → It flows in the order of the fourth port 64 of the switching valve 6 → the passage 7 d → the hot water heat exchanger 5.

  Thus, in normal operation of the engine 1, the cooling water flows in the order of the cooling water passage 1 w of the engine 1 → the cooling water passage 3 w of the exhaust gas heat exchanger 3. For this reason, the cooling water heated by the engine 1 can be further heated by the exhaust gas heat exchanger 3. Thereby, the temperature of the cooling water supplied to the inlet 5i of the hot water heat exchanger 5 can be made as high as possible, which can contribute to increasing the hot water output in the hot water heat exchanger 5.

  Furthermore, as described above, the cooling water flows in the order of the cooling water passage 1w of the engine 1 and then the cooling water passage 3w of the exhaust gas heat exchanger 3, so that the cooling water that is not heated by the exhaust gas heat exchanger 3 passes through the engine 1. Will flow. Therefore, the temperature of the cooling water supplied to the cooling water passage 1w of the engine 1 can be kept low. Therefore, the engine 1 can be efficiently cooled, and thermal deterioration of the oil flowing through the oil passage of the engine 1 can be suppressed.

  In such normal operation, the first valve 100 and the second valve 200 are in the form (ii) described above, or in the form (iii) when the temperature Twe is considerably high. As described above, in the form (ii), the cooling water flows to the hot water heat exchanger 5 but does not flow to the heat dissipation radiator 9. In the form (iii), the cooling water flows to both the hot water heat exchanger 5 and the radiator radiator 9 and the cooling water is prevented from overheating.

  As described above, according to the present embodiment, it is possible to solve the problem that it takes time to warm up after the engine 1 is started, and the temperature of the cooling water supplied to the engine 1 during normal operation after the engine 1 is warmed up. This is advantageous for suppressing overheating of the engine 1 and suppressing deterioration of engine oil and the like.

  Moreover, according to this embodiment, the switching valve 6 has the structure having the four ports 61 to 64 as described above, and the second port 62 of the switching valve 6 is the cooling water of the exhaust gas heat exchanger 3 in the warm-up operation. Although functioning as a discharge port for discharging the cooling water into the passage 3w, it is switched to a suction port for sucking the cooling water from the cooling water passage 3w of the exhaust gas heat exchanger 3 in a normal operation. Further, the third port 63 of the switching valve 6 functions as a suction port for sucking cooling water from the cooling water passage 1w of the engine 1 in the warm-up operation, but discharges the cooling water to the cooling water passage 1w of the engine 1 in the normal operation. The discharge port is switched. Since the second port 62 and the third port 63 of the switching valve 6 are switched in this way, the number of the switching valves 6 is sufficient, which is advantageous for cost reduction and prevention of an increase in size.

  Furthermore, according to this embodiment, in the warm-up operation, in the engine 1, the cooling water flows in the order of port 1x → port 1y, and in the exhaust gas heat exchanger 3, the cooling water flows in the order of port 3x → port 3y. On the other hand, in the normal operation, in the engine 1, the cooling water flows in the order of port 1y → port 1x, and in the exhaust gas heat exchanger 3, the cooling water flows in the order of port 3y → port 3x. Thus, for the cooling water passage 1w of the engine 1 and the cooling water passage 3w of the exhaust gas heat exchanger 3, the direction of the cooling water flowing during the warm-up operation and the direction of the cooling water flowing during the normal operation other than during the warm-up operation Are opposite to each other.

  FIG. 3 shows an example of the operating state of the apparatus. A characteristic line P1 indicates the driving state of the engine 1. A characteristic line P2 indicates the driving state of the radiator fan 90. A characteristic line P3 indicates exhaust heat recovery in the hot water heat exchanger 5. A characteristic line P4 indicates the temperature of the cooling water of the engine 1. A characteristic line P5 indicates the temperature of the oil of the engine 1.

  The engine 1 is started (time t1). When the drive of the engine 1 is stabilized, power generation is started from the temperature of the cooling water around the temperature Ta (time t2). As shown by the characteristic line P4, the temperature of the cooling water of the engine 1 increases. Further, as shown by the characteristic line P5, the temperature of the oil of the engine 1 rises with a delay from the temperature of the cooling water. From the temperature of the cooling water around the temperature Tc, exhaust heat recovery using the cooling water is started. The recovery of the exhaust heat is performed by driving the transport pump 55c.

  From time t3 after a while from the start time of exhaust heat recovery, the temperature of the cooling water of the engine 1 is suppressed from rising and is maintained in a substantially constant range. The temperature of the oil of the engine 1 is maintained in a substantially constant range after being delayed by the temperature of the cooling water. When the transfer pump 55c stops and the exhaust heat recovery ends (time t4), the temperature of the cooling water and the oil of the engine 1 rise again as indicated by the characteristic line P4 and the characteristic line P5. When the oil is overheated, the thermal deterioration of the oil is promoted. For this reason, when the temperature of the coolant of the engine 1 and the temperature of the oil become excessively high (time t5), the radiator fan 90 is rotationally driven, and the heat dissipation from the heat dissipation radiator 9 is enhanced. For this reason, overheating of the cooling water and oil of the engine 1 is prevented.

(Embodiment 2)
Embodiment 2 of the present invention will be specifically described. This embodiment has basically the same configuration and the same operation and effect as the first embodiment. However, the radiator radiator 9, the second valve 200, and the passage 7i are not provided. When the temperature of the cooling water rises and becomes high, in the first valve 100, the first opening 101 is opened, the second opening 102 is closed, and the third opening 103 is opened. For this reason, the cooling water flows into the hot water heat exchanger 5 and the passage 7h.

(Embodiment 3)
Embodiment 3 of the present invention will be specifically described. This embodiment has basically the same configuration and the same operation and effect as the first embodiment. The control unit 8 has a timer function. When the elapsed time from the time when the engine 1 is started is short, the control unit 8 determines that the engine is warming up. When the elapsed time is long, the control unit 8 determines that the operation is normal. Furthermore, a temperature sensor 8m is provided as an outside air temperature detection means, and fluctuations in outside air temperature are taken into consideration. That is, when the outside temperature detected by the temperature sensor 8m is low, the control unit 8 lengthens the elapsed time for determining the warm-up operation. When the outside air temperature is high, the control unit 8 shortens the elapsed time for determining the warm-up operation.

  In addition, the present invention is not limited to the embodiment described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist. For example, the engine 1 is not limited to a gas engine driven by combustion of fuel gas, but may be an engine driven by combustion of liquid fuel.

  INDUSTRIAL APPLICABILITY The present invention can be used in a cogeneration system that extracts power output from a generator and hot water output from a hot water heat exchanger.

It is a typical block diagram of the cogeneration system which shows warm-up operation. It is a typical block diagram of the cogeneration system which shows normal driving | operation. It is a graph which shows an example of a driving | running state. It is a schematic block diagram of the cogeneration system which concerns on Embodiment 2 and shows a normal driving | operation. It is a typical block diagram of the cogeneration system which concerns on Embodiment 3 and shows a normal driving | operation.

Explanation of symbols

  1 is an engine, 1w is a cooling water passage, 2 is a generator, 3 is an exhaust gas heat exchanger, 3w is a cooling water passage, 4 is a pump (cooling water transfer means), 5 is a hot water heat exchanger, and 6 is a switching valve ( Switching means), 61 is a first port, 62 is a second port, 63 is a third port, 64 is a fourth port, 7 is a passage, 8 is a control unit, and 9 is a heat dissipation radiator.

Claims (3)

An engine, a generator driven by the engine, an exhaust gas heat exchanger through which exhaust gas discharged from the engine passes, cooling water transfer means for supplying cooling water to the engine and the exhaust gas heat exchanger, and the engine And a hot water heat exchanger through which the heated cooling water passes through both of the exhaust gas heat exchangers, and takes out the power output from the generator and the hot water output from the hot water heat exchanger. In the cogeneration system,
A first path for performing a warm-up operation in which cooling water is passed in the order of the exhaust gas heat exchanger and the engine; and a second path for performing a normal operation in which cooling water is passed in the order of the engine and the exhaust gas heat exchanger; Switching means capable of switching between,
When the engine operation is determined to be a warm-up operation, the switching means is controlled to select the first route, and when the engine operation is determined to be a normal operation, the second route is And a control unit that controls the switching means to select.   In Claim 1, the heat dissipation radiator is provided, and when it is determined that the temperature of the cooling water flowing through the hot water heat exchanger has become higher than a predetermined temperature, the cooling water is flowed to the heat dissipation radiator from the heat dissipation radiator. A cogeneration system characterized in that a valve for switching the passage of cooling water is provided so as to dissipate heat. In Claim 1 or 2, the switching means has a first port, a second port, a third port, a fourth port,
The first port functions as a suction port for sucking in cooling water supplied from the cooling water transfer means in both warm-up operation and normal operation.
The second port functions as a discharge port for discharging cooling water to the cooling water passage of the exhaust gas heat exchanger during warm-up operation, and sucks cooling water from the cooling water passage of the exhaust gas heat exchanger during normal operation. Functions as a suction port,
The third port functions as a suction port for sucking cooling water from the cooling water passage of the engine during warm-up operation, and functions as a discharge port for discharging cooling water into the cooling water passage of the engine during normal operation,
The fourth port functions as a discharge port that discharges cooling water to the cooling water passage of the hot water heat exchanger in both warm-up operation and normal operation.

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