JP4488358B2 - Cogeneration equipment - Google Patents

Description

  The present invention relates to a cogeneration apparatus, and more particularly to a cogeneration apparatus having means for preventing freezing of condensed water generated by heat exchange.

  In recent years, cogeneration devices that collect and use the heat generated during operation have attracted attention from the viewpoint of effective use of energy in efforts to address global environmental problems. Small cogeneration systems are also beginning to become popular. In an exhaust heat recovery apparatus used in this type of cogeneration apparatus or the like, condensed water is generated when water vapor in the exhaust gas is cooled in the exhaust heat exchanger and the exhaust passage. Therefore, a waste heat recovery device is proposed in which a drain trap is provided at the bottom of the muffler through which the exhaust gas passes and the condensed water accumulated in the drain trap is discharged through the drain passage (for example, JP-A-11-72018).

  Condensed water generated while the medium recovered by the cogeneration system has risen to a normal stable temperature is blown off by the force of the exhaust gas, so even if the operation is stopped there, condensed water remains on the exhaust path. Little remains.

  Further, when the operation is started in a state where the installation environment temperature is below the freezing point, the generated condensed water may adhere to the inner wall of the exhaust system at the beginning of the operation, and it may freeze. However, the frozen condensed water is melted by being heated by the exhaust gas before the exhaust path is blocked, and in this case, almost no condensed water remains on the path of the exhaust system.

  However, if the operation is stopped for some reason immediately after the operation is started at a temperature below the freezing point, the condensed water may remain on the exhaust path without being blown off by the exhaust gas. If left in a freezing environment, the condensed water remaining on the exhaust path will freeze. Then, when the operation is started thereafter, the newly generated condensed water adheres to the frozen condensed water and freezes. As a result, the frozen condensed water may block the exhaust path and become inoperable.

  Moreover, in operation from a so-called cold soak state in which the outside air temperature is extremely low, there is a problem that frozen condensed water is difficult to melt due to a large heat capacity of the exhaust path.

In response to these problems, for example, a system has been proposed in which the engine is started after the cooling water is preheated with an electric heater when the outside air temperature is equal to or lower than a preset temperature lower than 0 ° C. ( JP, 2004-263589, A).
Japanese Patent Laid-Open No. 11-72018 JP 2004-263589 A

  The system described in Patent Document 2 requires several minutes to several tens of minutes of preheating time before starting the engine. In addition, since the power consumption of the electric heater is large, there is a problem that if the customer contract power is generally not large, such as for home use, the breaker may be activated unless the contract power is sufficiently increased in advance. .

  The object of the present invention is to solve the above problems, and in order to prevent the exhaust path from being clogged with condensed water frozen in the exhaust path, heating of the exhaust path and the like is promoted by using an electric heater. However, it aims at providing the cogeneration apparatus which can perform energy saving operation.

  The present invention provides an engine, a generator driven by the engine, a heat exchanger that recovers thermal energy from exhaust heat of the engine, and supplies the thermal energy recovered by the heat exchanger to an external heat load. In a cogeneration apparatus having a heat medium circulation path and a circulation pump for the heat medium provided in the circulation path, an electric heater for heating the heat medium circulating in the circulation path, and an environment of an exhaust system of the engine In the case where the temperature is a temperature at which the water vapor in the exhaust gas is expected to be frozen, there is a first feature in that there is provided means for operating the electric heater in accordance with starting the engine and the circulation pump. Further, the present invention has a second feature in that the electric heater is provided on the inlet side of the heat medium of the heat exchanger.

  Further, the present invention has a third feature in that at least a part of the output current of the generator is supplied to the electric heater. Furthermore, this invention has the 4th characteristic in the point comprised so that surplus electric power might be supplied to the said electric heater among the electric power generated by the said generator.

  According to the present invention having the above features, since the electric heater is operated at the time of starting the engine at a low temperature at which the ambient temperature is 0 ° C. or less and the water vapor in the exhaust gas is expected to be frozen, Due to the synergistic effect of the heating of the heat exchanger by circulation of the heated heat medium, the heating of the entire environment by the heat generated by the operation of the engine, and the heating of the exhaust path, the environmental temperature and exhaust gas temperature of the exhaust system The rise can be accelerated. Therefore, a great effect can be obtained in accelerating the melting of condensed water frozen in the exhaust path and suppressing freezing of water vapor in the exhaust gas.

  Further, in order to sufficiently raise the temperature of the entire heat medium circulation path only by heating the electric heater, it is necessary to operate for a long time with high power. However, by using both the heat from the engine operation and the heat from the electric heater, the heat exchanger and the exhaust path can be heated while fully utilizing the heat from the engine operation. Therefore, it is possible to shorten the operation time required for accelerating the melting of frozen condensed water and preventing freezing of water vapor in the exhaust gas, and a great power saving effect can be obtained.

  According to the present invention having the second feature, since the heat medium heated by the electric heater is immediately supplied into the heat exchanger, there is an effect that the heat exchanger can be heated.

  Further, according to the present invention having the third feature, since the electric heater can be operated by directly using the power generated by the generator, the power taken from the system side becomes unnecessary or reduced, and the energy is used. Efficiency can be improved. Since the electric heater consumes a large amount of power, operation with other loads exceeds the customer contract power and may exceed the breaker's remaining capacity. However, according to the third feature, by directly supplying the power consumption of the electric heater from the generator side, the amount of power drawn from the system side can be reduced, so that the power supplied from the system side reduces the customer contract power. It can be suppressed from exceeding.

  Furthermore, according to this invention which has a 4th characteristic, the surplus electric power which is not consumed with load among the electric power generated by a generator can be converted and utilized using an electric heater.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is a block diagram showing a configuration of a cogeneration apparatus including an exhaust heat recovery apparatus. The cogeneration apparatus 1 includes an engine 2 and a generator 3 driven by the engine 2. The engine 2 is provided with an oil pan 4 for storing lubricating oil. The oil pan 4 is provided with an oil heat exchanger (oil cooler) 5 that performs heat exchange between the oil in the oil pan 4 and the heat medium.

  The entire cogeneration apparatus 1 is completely covered with a casing C, and an upper part is an air filter 7 for purifying air taken into the cylinder head 6 of the engine 2, as well as an ECU 30, a power supply unit 31, and a motor driver unit. Control devices such as 32 are provided. The ECU 30 has an electronic governor device that converges the rotational speed of the engine 2 to a target value. As shown in the figure, the control device such as the ECU 30 is preferably installed in a room partitioned from the lower space by the partition plate P in order to make it less susceptible to the thermal effects of the engine 2.

  The cogeneration apparatus 1 includes a heat medium, that is, a cooling water circulation path 12 for recovering exhaust heat generated as the engine 2 is operated. The circulation path 12 is set so that cooling water is conveyed in the order of the oil heat exchanger 5, the exhaust heat exchanger 9, the exhaust manifold 8, and the cylinder head 6 of the engine 2 in order to efficiently recover the exhaust heat of the engine 2. Has been.

  The cooling water circulation path 12 is provided with water temperature sensors (heat medium sensors) 33 and 34 for detecting the temperature of the cooling water. The water temperature sensor 33 is provided in the cylinder head 6, and the water temperature sensor 34 is provided downstream from the installation position of the water temperature sensor 33, for example, near the outlet of the cogeneration device 1 for supplying hot water to an external heat load. The reason why the water temperature sensors 33 and 34 are provided at two locations is to detect the presence or absence of cooling water in the circulation path 12 (see Japanese Patent Application Laid-Open No. 2003-21393). Therefore, when detecting the presence or absence of cooling water by other means, one of the water temperature sensors 33 and 34 can be omitted. Further, the setting position of the water temperature sensor is not limited to these positions.

  The cogeneration apparatus 1 is provided with an internal temperature sensor 35 that senses the internal temperature. If the interior temperature sensor 35 is located at the bottom of the interior where the temperature is expected to be the lowest and is installed near the exhaust outlet of the exhaust heat exchanger 9, it senses the ambient temperature of the exhaust system and determines whether the exhaust system is frozen. It is convenient to obtain the condition data for The environmental temperature in the present embodiment is the ambient temperature of the exhaust system in the space in the casing C (inside the compartment), and is a value represented by the temperature sensed by the inside temperature sensor 35.

  A circulation pump for circulating the heat medium, that is, a water pump 10 is provided on the inlet side of the heat medium circulation path 12. With this arrangement, contact between the water pump 10 and the high-temperature heat medium is avoided, so that the seal member and the like are not easily deteriorated, and the life of the water pump 10 is extended.

  In addition, an electric heater 13 for heating the cooling water circulating through the circulation path 12 is provided. In order to prevent the electric heater 13 from becoming too large in relation to the generated power of the generator 3, for example, when the output power of the generator 3 is 1 kilowatt, the size of the electric heater 13 is 1 to 3 kilowatts. A degree is appropriate. The electric heater 13 is preferably provided on the heat medium inlet side of the exhaust heat exchanger 9. This is because it is convenient for the cooling water heated by the electric heater 13 to be immediately supplied to the exhaust heat exchanger 9 to heat the exhaust heat exchanger 9. However, the arrangement position of the electric heater 13 is not limited to the inlet side of the exhaust heat exchanger 9 as long as the purpose of heating the cooling water circulating through the circulation path 12 is achieved. During the operation of the electric heater 13, the water pump 10 is also operated, and the cooling water as the heat medium is heated by the electric heater 13 while being circulated through the circulation path 12.

  The cylinder head 6 is provided with a thermo cover 16 having a built-in thermostat, and the valve of the thermo cover 16 is switched below the preset temperature by the action of the thermostat so that the heat medium is not circulated to the cylinder head 6. Can do. This is for preventing excessive cooling of the cylinder head 6 and improving the starting performance of the engine 2.

  The heat medium is introduced from the water pump 10 to the oil heat exchanger 5 in the oil pan 4 to exchange heat with the oil recovered from the engine 2 to cool the oil and obtain heat from it. Subsequently, the heat medium exchanges heat with the exhaust gas from the engine 2 in the exhaust heat exchanger 9 to obtain heat. The heat medium that has risen in temperature by obtaining heat in the oil heat exchanger 5 and the exhaust heat exchanger 9 further passes through a cooling wall comprising a cylinder wall of the engine 2 and a pipe line provided in the cylinder head 6, that is, a water jacket 6A. Heat is recovered and the temperature is further increased. The heat medium whose temperature has increased by collecting the exhaust heat is circulated to an external heat load such as a boiler unit.

  On the other hand, the exhaust gas from the engine 2 is discharged to the outside through the exhaust manifold 8, the exhaust heat exchanger 9, and a plurality of exhaust mufflers (see FIG. 3).

  FIG. 3 is a perspective view showing the configuration of the exhaust system. A plurality of exhaust mufflers 23, 25, and 27 are provided in the exhaust system. The first exhaust hose 17 drawn from the bottom of the exhaust heat exchanger 9 disposed at the lower part of the cogeneration apparatus 1 is connected to an exhaust temperature sensor hose 19 via an exhaust pipe 18. The exhaust temperature sensor hose 19 is connected to the second exhaust hose 21 via the exhaust temperature sensor pipe 20. An exhaust temperature sensor 22 is attached to the exhaust temperature sensor pipe 20. The upper end of the second exhaust hose 21 extending almost directly above is connected to the upper portion of the first exhaust muffler 23.

  The upper end of the third exhaust hose 24 is connected to the lower part of the first exhaust muffler 23. The lower end of the third exhaust hose 24 is connected to the second exhaust muffler 25. The lower end of the fourth exhaust hose 26 is connected to the lower part of the second exhaust muffler 25. The fourth exhaust hose 26 extends upward, and its upper end is connected to the upper part of the third exhaust muffler 27 located at the upper part of the cogeneration apparatus 1. A duct 274 having an exhaust port is attached to the upper portion of the third exhaust muffler 27. A drain passage including a drain hose 28 and a drain pipe 29 is connected to the lower surface of the third exhaust muffler 27.

  The shell or housing of the exhaust heat exchanger 9 is formed of a metal material such as stainless steel, but the first and second exhaust mufflers 23 and 25 and the third exhaust muffler 27 constitute an exhaust gas passage having a lowered temperature. Therefore, it is good to form each by the blow molding of a resin material (for example, polypropylene).

  Exhaust gas flows indicated by arrows in FIG. 3 will be described. The exhaust gas of the engine 2 is introduced into the exhaust heat exchanger 9 from above. In the exhaust heat exchanger 9, heat is exchanged with the cooling water conveyed through the exhaust heat exchanger portion of the circulation path 12 piped inside. The exhaust gas cooled in the exhaust heat exchanger 9 is introduced into the first exhaust muffler 23 via the first exhaust hose 17, the exhaust pipe 18, the exhaust temperature sensor hose 19, the exhaust temperature sensor pipe 20, and the second exhaust hose 21. Thus, the first stage mute is performed.

  Exhaust gas discharged from the first exhaust muffler 23 is introduced into the second exhaust muffler 25 and silenced in the second stage. The exhaust gas discharged from the second exhaust muffler 25 is guided further upward to reach the third exhaust muffler 27, and is silenced in three stages by the third exhaust muffler 27, and the exhaust gas is discharged from the duct 274 to the outside.

  Exhaust gas from the engine 2 is cooled by taking heat away from the heat exchange portions described above. At this time, moisture in the exhaust gas is condensed to generate condensed water. Condensed water generated in the exhaust system is transported to the third exhaust muffler 27 according to the flow of the exhaust gas, and is discharged to the outside through the drain hose 28 and the drain pipe 29.

  By the way, this condensed water may remain in the exhaust system after a short operation such as a trial operation, and there is a possibility that the condensed water will freeze when the environmental temperature of the exhaust system reaches 0 ° C. If the condensed water generated by resuming the operation adheres to the frozen condensed water, the freezing range may be expanded, and the hose connecting between the plurality of mufflers provided in the exhaust system and between the muffler and the exhaust heat exchanger 9 It is conceivable to close the connection part.

  In the present embodiment, in particular, by operating the electric heater 13 in accordance with the start of the engine, the environmental temperature of the exhaust system and the exhaust gas temperature are accelerated, and the freezing release of the condensed water in the exhaust path is promoted. The water vapor in the exhaust gas is prevented from freezing.

  FIG. 4 is a block diagram showing a power system of the cogeneration apparatus 1 including the electric heater 13. In the figure, an inverter device 41 includes a three-phase bridge circuit 42, a booster circuit 43, an inverter circuit (inverter bridge circuit) 44, and a noise filter 45. The output side of the inverter device 41 is connected to the interconnection terminal 47 via a breaker 46 with a leakage detector. The switchboard 48 includes a cogeneration breaker 49, a load breaker 50, and a main breaker 51, and is connected so that the power from the commercial power system 52 and the power generated by the inverter device 41 are connected to the load 53. Is done. The output side of the inverter device 41 is further connected to the electric heater 13 via the heater switch 54. A heater control unit 55 that controls the heater switch 54 is provided.

  The power generation output of the generator 3 is rectified by the three-phase bridge circuit 42. The rectified voltage is boosted to a predetermined voltage value by the booster circuit 43, converted to alternating current of a predetermined frequency (commercial frequency) by the inverter circuit 44, and output through the noise filter 45. The output power of the inverter device 41 is supplied to the load 53 in conjunction with the commercial power system 52 and supplied to the electric heater 13 while the heater switch 54 is turned on by the control of the power supply heater control unit 55. Is done.

  FIG. 1 is a block diagram showing the main functions of an ECU according to an embodiment of the present invention. In FIG. 1, the internal temperature sensor 35 is installed in the vicinity of the exhaust heat exchanger 9 as described above, and senses the environmental temperature of the exhaust system. The water temperature sensor 34 detects the temperature of the cooling water on the downstream side of the cylinder head 6 of the engine 2, which is a heat exchange unit located at the most downstream side of the circulation path 12. As described above, the exhaust gas temperature sensor 22 is provided in the exhaust system between the exhaust heat exchanger 9 and the first exhaust muffler 23 to detect the exhaust gas temperature. The engine start instruction detection unit 36 inputs an engine start command START to the engine control unit 37 when an operation start instruction is input from the control panel.

  The environmental temperature determination unit 38 determines whether the environmental temperature T1 of the exhaust system detected by the internal temperature sensor 35 is 0 ° C. or less. This is for determining whether or not the temperature of the water vapor in the exhaust gas is expected to be frozen. If the environmental temperature T1 is 0 ° C. or lower, the environmental low temperature signal AL is set to a high level (H).

  The exhaust gas temperature determination unit 39 determines whether or not the exhaust gas temperature T2 sensed by the exhaust gas temperature sensor 22 is equal to or higher than the reference exhaust gas temperature TGref. The reference exhaust gas temperature TGref is an exhaust gas temperature reference value set as the first condition for completion of warm-up. Since the water vapor in the exhaust gas starts condensing when it becomes 63 ° C. or lower, the reference exhaust gas temperature TGref is set to 60 ° C. just before the start of the water vapor condensation as an example. If the exhaust gas temperature T2 is equal to or higher than the reference exhaust gas temperature TGref, the exhaust warm signal EX is set to a high level (H).

  The water temperature determination unit 40 determines whether or not the cooling water temperature T3 detected by the water temperature sensor 34 is equal to or higher than the reference cooling water temperature TWref. The reference coolant temperature TWref is a reference value of the coolant temperature set as the second condition for completion of warm-up. The reference cooling water temperature TWref is 30 ° C. as an example. If the coolant temperature T3 is equal to or higher than the reference coolant temperature TWref, the coolant warm signal CL is set to a high level (H).

  The power consumption detection unit 56 calculates the power supplied to the load 53. The generated power detection unit 57 calculates the generated power of the generator 3. The surplus power calculation unit 58 compares the power supplied to the load 53 with the power generated by the generator 3, and when the generated power exceeds the power surplus signal Ps, sets the power surplus signal Ps to a high level (H). To do.

  When the engine start command START is input, the engine control unit 37 reads the environmental low temperature signal AL, and if the environmental low temperature signal AL is high level, the engine control unit 37 does not control the engine 2 to the rated rotational speed for a predetermined time, Perform idling operation. That is, the engine speed control (electronic governor control) is performed by setting the target value for the rotational speed control to a value during idling operation. In idling operation, the amount of condensed water generated is small because the amount of fuel (gas) consumption is small. In addition, since the combustion temperature is high, the condensed water remaining in the exhaust path can be easily blown off, and there is an effect of preventing freezing. Immediately after the idling operation for a predetermined time, the engine speed may be shifted to the normal operation for setting the engine speed to the rated speed, but in order to further ensure the effect of freezing prevention, the exhaust gas temperature and the coolant temperature Is preferably added as a criterion.

  That is, after the idling operation for the predetermined time, the exhaust warming signal EX and the cooling water low temperature signal CL are read, and if both of them are at a low level, the idling operation is maintained. When at least one of the exhaust warm-up signal EX and the coolant warm-up signal CL is at a high level, the idling operation is stopped and the control proceeds to control for setting the engine speed to the rated speed, and power generation is performed.

  When the environmental temperature signal AL is at a low level, that is, not a low temperature of 0 ° C. or lower, normal operation is started regardless of the levels of the exhaust warming signal EX and the coolant warming signal CL when the engine start command START is input. .

  When the engine start command START is input, the heater control unit 55 reads the environmental low temperature signal AL. If the environmental low temperature signal AL is high, the heater controller 55 energizes the coil RY54 of the heater switch 54 to provide a relay contact, that is, a heater switch. 54 is turned on. When the switch 54 is turned on, the electric heater 13 is supplied with power from the generator 3 and the commercial power system 52. When electric power is supplied to the electric heater 13, the cooling water in the circulation path 12 is heated by the heat generated by the electric heater 13. Since the electric heater 13 is directly connected as a load of the generator 3, generated electric power is directly supplied to the electric heater 13. When the generated power is insufficient, the shortage is supplemented with the power of the commercial power system 52.

  When the engine start command START is input, the pump control unit 59 operates the circulation pump 10 to circulate cooling water through the circulation path 12.

  As described above, in the present embodiment, it is determined from the environmental temperature of the exhaust system that water vapor in the exhaust gas may be frozen, and the timing for shifting to normal operation is determined. Further, it is determined that the water vapor in the exhaust gas may be frozen based on the environmental temperature of the exhaust system, and the electric heater 13 is operated to heat the cooling water circulating in the circulation path 12.

  The electric heater 13 can supply electric power from the commercial power system 52 and the generator 3, but the load 53 is directly connected as a load of the generator 3, so that the electric power consumed by the electric heater 13 is reduced by the generator 3. When the generated power exceeds, the electric heater 13 can be operated only by the generated power of the generator 3.

  The engine control unit 37 may make the determination based on at least one of the exhaust gas temperature T2 and the cooling water temperature T3, and may maintain idling operation while both are below the reference temperature. Also good.

  The timing of stopping the operation of the electric heater 13 may be when it is determined that the exhaust gas temperature T2 has reached the reference exhaust gas temperature TGref, or when a preset time has elapsed since the start of the operation. Good. Further, it may be the time when it is determined that the cooling water temperature T3 has reached the reference cooling water temperature TWref.

  In addition, it is not restricted to these temperature conditions and elapsed time, and when there is a surplus that is not consumed by the load 53 in the generated power of the generator 3, the electric heater 13 may be operated using this surplus power. In this case, the electric heater 13 can be composed of a plurality of heater portions, and the number of heater portions to be operated can be increased according to the amount of surplus power. By making the heater part to be used variable, surplus power can be efficiently converted into heat energy and used for heating an external hot water storage or the like.

  FIG. 5 is a flowchart of processing corresponding to the function of the engine control unit 37. In step S1, it is determined whether or not there is an engine start command START. If the engine start command START is input, it is determined in step S2 whether the environmental temperature T1 of the exhaust system is 0 ° C. If the environmental temperature T1 is not 0 ° C., the process proceeds to step S6, the engine speed target value is set to a value for rated operation, the engine 2 is normally operated, and power generation is started. At the start of operation of the engine 2, the water pump 10 is also driven, and the circulation of the cooling water is started.

  When the environmental temperature T1 is 0 ° C. or lower, the condensed water in the exhaust path may be frozen. Therefore, when the environmental temperature T1 is 0 ° C. or lower, the normal operation is not immediately started and the process proceeds to step S3 to perform the idling operation. That is, the engine speed target value for idling operation is set to control the engine speed. Next, it progresses to step S4 and it is judged whether exhaust gas temperature T2 is more than the reference | standard exhaust gas temperature TGref. If the exhaust gas temperature TGref is equal to or higher than the reference exhaust gas temperature TGref, the process proceeds to step S6, the idling operation is stopped, and the normal operation is started. If the exhaust gas temperature T2 is not equal to or higher than the reference exhaust gas temperature TGref, the process proceeds to step S5, and it is determined whether or not the cooling water temperature T3 is equal to or higher than the reference cooling water temperature TWef. If the cooling water temperature T3 is equal to or higher than the reference cooling water temperature TWref, the idling operation is stopped, the process proceeds to step S6, the idling operation is stopped, and the normal operation is started.

  FIG. 6 is a flowchart of processing corresponding to the function of the heater control unit 55. In step S10, it is determined whether or not there is an engine start command START. If the engine start command START is input, it is determined in step S11 whether the environmental temperature T1 of the exhaust system is 0 ° C. or less.

  When the environmental temperature T1 is 0 ° C. or lower, the process proceeds to step S12, the heater switch 54 is turned on, and the electric heater 13 is operated. If the electric heater 13 is operated, the process proceeds to step S13, where a judgment criterion for stopping the electric heater 13, that is, an operating state in which condensed water is not generated, or a state in which there is no fear of freezing of water vapor in the exhaust gas. Judge whether the criteria of This judgment criterion can be whether or not the coolant temperature T3 and the exhaust gas temperature T2 have risen to a predetermined temperature, whether or not the electric heater 13 has been operated for a predetermined time, and the like. If the determination in step S13 is affirmative, the process proceeds to step S14, where the heater switch 54 is turned off and the operation of the electric heater 13 is stopped.

  The specific values such as the environmental temperature and the reference exhaust gas temperature shown in the present embodiment are examples, and are not limited to these. For example, the determination of the environmental temperature T1 is not limited to whether or not it is 0 ° C. or less, but may be performed based on whether or not the temperature is substantially equal to or less than 0 ° C. from the viewpoint of the cooling water freezing range. Good.

  In addition, according to the present embodiment, not only the effect of making the exhaust passage freezing and clogging difficult to occur, but also the electric heater is operated when the engine is started, so that the heat generated by the cranking can be taken away by the cooling water. Therefore, cranking is performed while the temperature near the engine head is high. As a result, the startability of the engine is improved due to the effects of an increase in the in-cylinder temperature and a reduction in friction near the cylinder head.

It is a principal part functional block diagram of the cogeneration apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the cogeneration apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows the structure of the engine exhaust system of the cogeneration apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the electric power system of the cogeneration apparatus containing an electric heater. It is a flowchart which shows the principal part process of an engine control part. It is a flowchart which shows the principal part process of a heater control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cogeneration apparatus, 2 ... Engine, 3 ... Generator, 5 ... Oil heat exchanger, 6 ... Cylinder head, 8 ... Exhaust manifold, 9 ... Exhaust heat exchanger, 12 ... Circulation path, 13 ... Electric heater, 19 21, 24, 26 ... exhaust hose, 22 ... exhaust gas temperature sensor, 23 ... first exhaust muffler, 25 ... second exhaust muffler, 27 ... third exhaust muffler, 30 ... ECU, 34 ... water temperature sensor, 35 ... warehouse Internal temperature sensor 37 ... Engine control unit 38 ... Environmental temperature determination unit 39 ... Exhaust gas temperature determination unit 40 ... Water temperature determination unit 41 ... Inverter device 52 ... Commercial power system 53 ... Load 54 ... Heater switch 55 ... Heater control unit

Claims (4)

An engine, a generator driven by the engine, a heat exchanger for recovering heat energy from the exhaust heat of the engine, and a circulation of a heat medium for supplying the heat energy recovered by the heat exchanger to an external heat load A cogeneration apparatus having a path and a circulation pump of the heat medium provided in the circulation path,
An electric heater for heating the heat medium circulating in the circulation path;
For temperature environmental temperature of the exhaust system of the engine is expected to freezing of water vapor in the exhaust gas, characterized by comprising a means for actuating the electric heater continues to start the engine and the circulation pump Cogeneration equipment.   The cogeneration apparatus according to claim 1, wherein the electric heater is provided on an inlet side of the heat medium of the heat exchanger.   The cogeneration apparatus according to claim 1 or 2, wherein at least a part of an output current of the generator is supplied to the electric heater.   The cogeneration apparatus according to claim 1, wherein surplus electric power is supplied to the electric heater from the electric power generated by the generator.

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