JP2003035467A - Engine cooling equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide engine cooling equipment wherein the capacity of an exhaust gas heat exchanger is improved. SOLUTION: In the engine cooling equipment 1, a cooling water circuit 40 is so constituted that cooling water accelerated by a cooling water pump 39 circulates to this pump 39, flowing sequentially through an engine 13, a first three-way valve 41, a second three-way valve 42, a heat-recovery heat exchanger 33, a first joining part 43 wherein the cooling water branched by and flowing from the second three-way valve 42 joins, a radiator 22 and a second joining part 44 wherein the cooling water branched by and flowing from the first three- way valve 41 joins. In this constitution, the exhaust gas heat exchanger 50 conducting recovery of heat of the exhaust gas of the engine 13 is provided in the cooling water circuit 40 between the radiator 22 and the second joining part 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling device for cooling an engine which is a drive source of an engine heat pump type air conditioner, a cogeneration system and the like.

[0002]

2. Description of the Related Art Generally, for example, a gas engine of a gas heat pump type air conditioner and a gas engine cooling device for cooling the gas engine are known. This type of gas engine cooling device is a gas engine that drives a load,
A radiator provided in a cooling water circuit for cooling this gas engine, an exhaust gas heat exchanger for recovering heat of exhaust gas of this gas engine, a cooling water pump for circulating cooling water in the cooling water circuit, and a cooling water A three-way valve for controlling the circuit is provided, and by switching the three-way valve, the cooling water is circulated so that the temperature of the cooling water becomes an appropriate temperature.

In the conventional structure, the exhaust gas heat exchanger of this gas engine is provided in the cooling water circuit immediately before the cooling water cooled by the radiator returns to the gas engine.

[0004]

However, in the above-mentioned conventional structure, if the capacity of the exhaust gas heat exchanger is improved, the temperature of the cooling water to the gas engine must be lowered accordingly, so that the cooling water is cooled. If the temperature is too low, the gas engine will malfunction, so it was necessary to operate in the prescribed temperature range. Therefore, the temperature of the cooling water entering the exhaust gas heat exchanger is set to about 65 so that the temperature of the cooling water in the gas engine is maintained in the temperature range of 70 to 100 ° C., for example.
Generally, the temperature is set above ° C, which limits the heat recovery capacity of the exhaust gas heat exchanger.

By the way, in recent years, in order to prevent global warming, further improvement in energy consumption efficiency of air conditioners has been demanded.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide an engine cooling device in which the capacity of the exhaust gas heat exchanger is improved while maintaining the temperature of the cooling water returning to the engine at an appropriate temperature. To do.

[0007]

In order to solve the above problems, the invention according to claim 1 provides an engine for driving a load, a radiator provided in a cooling water circuit for cooling the engine, and the cooling water circuit. A heat recovery heat exchanger that recovers heat from the cooling water, a cooling water pump that circulates the cooling water in the cooling water circuit, and first and second three-way valves that control the flow of the cooling water circuit. In an engine cooling device that circulates the cooling water so that the temperature of the cooling water becomes an appropriate temperature by appropriately switching the three-way valve, the cooling water circuit is configured such that the cooling water accelerated by the cooling water pump is the engine, the first three-way valve, The second three-way valve, the heat recovery heat exchanger, the first joint where the cooling water branched from the second three-way valve joins, the radiator, and the second joint where the cooling water branched from the first three-way valve joins in order. To circulate to the cooling water pump Configured, and is characterized by providing an exhaust gas heat exchanger for heat recovery of the exhaust gas of the engine coolant circuit between the radiator and the second joined section.

According to a second aspect of the present invention, in the cooling water circuit, the third radiator is provided upstream of the radiator so as to bypass the radiator.
It is characterized in that a three-way valve is provided, and a third joint portion where the cooling water branched from the third three-way valve joins is provided downstream of the radiator.

According to the third aspect of the present invention, the load is the compressor of the heat pump type air conditioner, and the heat recovery heat exchanger is joined to the refrigerant circuit of the heat pump type air conditioner, and the refrigerant of this refrigerant circuit is It is characterized by heating.

According to a fourth aspect of the present invention, the load is the generator of the cogeneration system, and the heat recovery heat exchanger is joined to the cooling water circuit of the cogeneration system to heat the cooling water of the cooling water circuit. It is characterized by doing.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a refrigerant / cooling water circuit diagram of a gas engine heat pump type air conditioner (engine cooling device) showing a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a gas engine heat pump type air conditioner (air conditioner). The air conditioner 1 includes an indoor unit 3 and an outdoor unit 5.

The indoor unit 3 includes an indoor heat exchanger 7 and
The indoor expansion valve 9 and the like are provided. Although only one indoor unit 3 is shown in this figure, a plurality of indoor units 3 can be installed.

The outdoor unit 5 includes a gas engine 13 using natural gas or the like as fuel (other internal combustion engine may be used).
And the compressor 1 driven by this gas engine 13.
5, a four-way valve 17 that switches the flow of refrigerant between heating operation and refrigerant operation, an outdoor expansion valve 19, and an outdoor heat exchanger 2
1, a cooling water circuit 40 of the gas engine 13, a heat recovery heat exchanger (refrigerant heater) 33 that recovers heat from the cooling water of the cooling water circuit, and the like.

The indoor heat exchanger 7 of the indoor unit 3, the indoor expansion valve 9 and the compressor 15, the four-way valve 17, the outdoor expansion valve 19, the outdoor heat exchanger 21, and the refrigerant heater 33 of the outdoor unit 5 are piped together. The refrigerant circuit 25 is configured by connecting with.

Further, the cooling water circuit 4 of the gas engine 13
Reference numeral 0 denotes a radiator 22 that dissipates the waste heat of the gas engine 13 to the atmosphere, and cooling water of the cooling water circuit 40.
Heat recovery heat exchanger 33 (refrigerant heater) for heating refrigerant 5
A cooling water pump 39 for circulating cooling water in the cooling water circuit 40; a first three-way valve 41 (proportional control valve) and a second three-way valve 42 (proportional control valve) for controlling the flow of the cooling water circuit 40; The exhaust gas heat exchanger 50 recovers the heat of the exhaust gas of the gas engine 13.

The cooling water circuit 40 includes a cooling water pump 39.
The cooling water accelerated by the gas engine 13, the first three-way valve 4
1, second three-way valve 42, refrigerant heater 33, second three-way valve 42
From the first joint part 43 where the cooling water branched from the above joins, the radiator 22, the exhaust gas heat exchanger 50, and the second joint part 44 where the cooling water branched from the first three-way valve 41 joins and flows again in this order. It is configured to circulate to the pump 39.
The first three-way valve 41 and the second three-way valve 42 are the gas engine 1
The opening degree is appropriately switched by a control device (not shown) so that the temperature of the cooling water in 3 becomes an appropriate temperature (for example, 70 to 100 ° C.).

The outdoor heat exchanger 21 and the radiator 22 described above are installed in parallel and are air-cooled by the outdoor blower 28.

The operation of each part during operation of the air conditioner 1 will now be described. During the heating operation, the flow of the refrigerant in the refrigerant circuit 25 is switched in the four-way valve 17 by the four-way valve 17 as shown by the solid line, and the outdoor unit 5 is operated. The refrigerant discharged from the compressor 15 is a four-way valve 17, an indoor heat exchanger 7 (heating the room), an indoor expansion valve 9 (open), an outdoor expansion valve 19 (throttle control), an outdoor heat exchanger 21 (from the outside air). Heat absorption), the refrigerant heater 33, and the compressor 15 flow again in this order.

At this time, the cooling water circuit 40 of the air conditioner 1
The cooling water accelerated by the cooling water pump 39 is heated to about 80 ° C by the gas engine 13, and the cooling water is heated by the first three-way valve 41 to 2 ° C.
The main flow (about 50%) is branched and branched to the refrigerant heater 33 by the second three-way valve 42 (about 100%), the refrigerant is heated by the refrigerant heater 33, and the radiator 22 is passed through the first joint 43. About 4
It is cooled to 5 ° C, heated to about 60 ° C by the exhaust gas heat exchanger 50, and merged at the second joint 44 with a substream (about 50%) of about 80 ° C branched from the first three-way valve 41. About 70 ° C
The temperature of the cooling water pump 39 is raised to circulate again. In this way, the temperature of the cooling water entering the exhaust gas heat exchanger 50 can be significantly lowered as compared with the conventional temperature (about 65 ° C.), and the heat recovery amount by the exhaust gas heat exchanger 50 can be greatly improved. Has become.

During the cooling operation, the flow of the refrigerant in the refrigerant circuit 25 is such that the refrigerant flow path is switched in the four-way valve 17 as shown by the dotted line, and the refrigerant discharged from the compressor 15 of the outdoor unit 5 is transferred to the four-way valve 17. , Refrigerant heater 33, outdoor heat exchanger 2
1 (heat is radiated to the outside air), the outdoor expansion valve 19 (open), the indoor expansion valve 9 (throttle control), the indoor heat exchanger 7 (cooling the room), and circulates to the compressor 15 again.

At this time, the cooling water circuit 40 of the air conditioner 1
The cooling water accelerated by the cooling water pump 39 is heated to about 80 ° C. by the gas engine 13 and flows about 100% to the second three-way valve 42 side by the first three-way valve 41, and by the second three-way valve 42. The refrigerant heater 33 is bypassed (about 100%), cooled to about 65 ° C by the radiator 22 via the first joint 43 and heated to about 70 ° C by the exhaust gas heat exchanger 50, and the second joint 44
And then circulates again to the cooling water pump 39.

Further, as in the second embodiment of the present invention shown in FIG. 2, a third three-way valve 51 is provided upstream of the radiator 22 so as to bypass the radiator 22 in the cooling water circuit 40, and the radiator 22 is also provided. By providing the third joint portion 52 where the cooling water diverted from the third three-way valve 51 joins downstream of, the radiator 22 is bypassed in the severe winter season and the heat radiation from the radiator 22 is prevented to prevent the cooling water from being overheated. Cooling water circuit 40 to prevent cooling
It is possible to keep the water temperature of the water at an appropriate temperature.

Further, as described above, Embodiment 1 of the present invention
2 explained the engine heat pump type air conditioner, the engine cooling device is applied to, for example, a cogeneration system, the load of the engine is a generator of the cogeneration system, and the heat recovery heat exchanger is the cogeneration system. It is also possible to improve the efficiency of the cogeneration system, such as hot water supply equipment, by joining the cooling water circuit of the system and heating the cooling water of this cooling water circuit.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified without departing from the gist of the present invention.

[0026]

As described above, according to the invention of claim 1, an engine for driving a load, a radiator provided in a cooling water circuit for cooling the engine, and cooling water for the cooling water circuit. The heat recovery heat exchanger for recovering heat from the cooling water, the cooling water pump for circulating the cooling water in the cooling water circuit, and the first and second three-way valves for controlling the flow of the cooling water circuit are provided. In an engine cooling device that circulates the cooling water so that the temperature of the cooling water is appropriately switched by appropriately switching the cooling water circuit, the cooling water accelerated by the cooling water pump is the engine, the first three-way valve, the second three-way Valve, heat recovery heat exchanger, the first where the cooling water split from the second three-way valve joins
The joint portion, the radiator, and the second joint portion where the cooling water branched from the first three-way valve joins are sequentially flowed and circulated to the cooling water pump, and between the radiator and the second joint portion. By providing an exhaust gas heat exchanger that recovers the heat of the exhaust gas of the engine in the cooling water circuit, it is possible to provide an engine cooling device with improved performance of the exhaust gas heat exchanger.

According to the second aspect of the present invention, in the cooling water circuit, a third three-way valve is provided upstream of the radiator so as to bypass the radiator, and is diverted from the third three-way valve downstream of the radiator. By providing the third joint portion where the cooling water merges, it is possible to provide the engine cooling device in which the capacity of the exhaust gas heat exchanger is improved.

According to the third aspect of the present invention, the load is the compressor of the heat pump type air conditioner, and the heat recovery heat exchanger is joined to the refrigerant circuit of the heat pump type air conditioner. By heating the refrigerant,
It is possible to provide a heat pump type air conditioner in which the capacity of the exhaust gas heat exchanger is improved.

According to the fourth aspect of the present invention, the load is the generator of the cogeneration system, and the heat recovery heat exchanger is joined to the cooling water circuit of the cogeneration system. It is possible to provide a cogeneration system in which the capacity of the exhaust gas heat exchanger is improved by heating the.

[Brief description of drawings]

FIG. 1 is a refrigerant / cooling water circuit diagram of an engine heat pump type air conditioner showing a first embodiment of the present invention.

FIG. 2 is a refrigerant / cooling water circuit diagram of an engine heat pump type air conditioner showing a second embodiment of the present invention.

[Explanation of symbols]

1 Air conditioner 3 indoor units 5 outdoor unit 13 gas engine 15 compressor 21 outdoor heat exchanger 22 radiator 25 Refrigerant circuit 33 heat recovery heat exchanger 40 cooling water circuit 41 first three-way valve 42 Second three-way valve 43 First joint 44 Second joint 50 Exhaust gas heat exchanger

Claims (4)

[Claims] 1. An engine for driving a load, a radiator provided in a cooling water circuit for cooling the engine, a heat recovery heat exchanger for recovering heat from cooling water in the cooling water circuit, and the cooling water circuit. A cooling water pump for circulating cooling water and first and second three-way valves for controlling the flow of the cooling water circuit are provided, and the temperature of the cooling water becomes an appropriate temperature by appropriately switching these three-way valves. In the engine cooling device that circulates cooling water as described above, in the cooling water circuit, the cooling water accelerated by the cooling water pump is the engine, the first three-way valve, the second three-way valve,
The heat recovery heat exchanger, the first joint where the cooling water branched from the second three-way valve joins, the radiator, and the second joint where the cooling water branched from the first three-way valve joins in order. An exhaust gas heat exchanger configured to circulate to the cooling water pump and provided in the cooling water circuit between the radiator and the second joint portion for performing heat recovery of exhaust gas of the engine is provided. A characteristic engine cooling system. 2. In the cooling water circuit, a third three-way valve is provided upstream of the radiator so as to bypass the radiator, and cooling water branched from the third three-way valve is provided downstream of the radiator. The engine cooling device according to claim 1, further comprising a third joining portion that joins. 3. The load is a compressor of a heat pump type air conditioner, and the heat recovery heat exchanger is joined to a refrigerant circuit of the heat pump type air conditioner to heat the refrigerant of the refrigerant circuit. The engine cooling device according to claim 1 or 2, characterized in that. 4. The load is a generator of a cogeneration system, and the heat recovery heat exchanger is connected to a cooling water circuit of the cogeneration system to heat the cooling water of the cooling water circuit. The engine cooling device according to claim 1 or 2, which is characterized.