JP2568880B2 - Gas engine fuel supply system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel supply device for a gas engine, and more particularly to a fuel supply device for a gas engine used as a drive source of a heat pump air conditioner.

[Prior Art] A gas engine is operated with a mixture of fuel gas such as city gas or propane gas and intake air at a predetermined mixture ratio by a mixer. Recently, a heat pump type air conditioner using this gas engine as a driving source has been commercialized and has been spotlighted. In the case of this air conditioner as well, similarly to the heat pump type air conditioner using an electric motor as a drive source, thermo-on / off control is performed so that the room temperature falls within a predetermined temperature range. Is stopped, and when the room temperature falls out of the above temperature range, the gas engine is started again to restart the heat pump operation.

In order to smoothly perform thermo-on / off control in such an air-conditioning operation, it is necessary to start the gas engine in the warmed-up state in a short time and surely. For this purpose, it is necessary to control the mixing ratio between the fuel gas and the intake air so as to be a predetermined ratio set in the mixer.

However, the above-mentioned gas engine is generally housed in the surrounding engine room for soundproofing, so even when the gas engine is temporarily stopped, the atmosphere in the engine room is considerably higher than the outside temperature. The state is maintained at a high temperature. On the other hand, since the density of fuel gas, which is a gas, changes depending on pressure and temperature, when a low-temperature fuel gas is introduced into an atmosphere such as the above-mentioned engine room, which is considerably higher than the outside air temperature, the fuel becomes less dense. There is a problem that the start of the gas engine becomes unstable due to the change in gas density.

That is, conventionally, of the two factors of the pressure and the temperature affecting the density of the fuel gas as described above, the pressure can be managed because the zero governor is provided as a pressure regulator in the fuel gas supply line. However, it was difficult to reliably control the temperature, and the fact was that the hot start became unstable.

[Object of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the gas engine housed in the engine room, to facilitate the management of the mixing ratio between the fuel gas and the intake air, and to reliably perform the hot start of the gas engine. Another object of the present invention is to provide a fuel supply device which has a reduced capacity.

[Configuration of the invention]

The present invention that achieves the above object is a gas engine that is housed in an engine room and is operated by a mixture of fuel gas regulated by a zero governor and air purified by an air cleaner, wherein the air cleaner is housed in the engine room. On the other hand, a storage chamber for temporarily storing fuel gas is provided in the middle of the fuel gas supply line, and this storage chamber is housed in the engine room or a space room adjacent to the engine room. .

〔Example〕

 Hereinafter, the present invention will be described with reference to embodiments shown in the drawings.

1 and 2 show a unit part of a gas engine of the present invention used as a drive source of a heat pump type air conditioner, and constitute a part of the air conditioner system shown in FIG.

The engine unit I has an engine room 21 surrounded by a soundproofing material 20 and houses therein a gas engine 1 driven by a fuel gas such as city gas or propane gas. And the compressor 3 are attached. The compressor 3 is driven by the gas engine 1 and compresses a refrigerant such as Freon into a high-temperature and high-pressure gas.

The fuel gas is supplied from an external supply source (not shown) to the zero governor 5 which is a pressure adjuster via the solenoid valves 4 and 4, where the pressure is adjusted to the atmospheric pressure, and then supplied to the mixer 7 via the fuel supply pipe 6. You. The zero governor 5 is provided in a space room 22 adjacent to the engine room 21. Although the structure is not particularly limited, generally, a structure in which a high-pressure fuel gas from an external supply source is compared with the atmospheric pressure using a diaphragm and the pressure is reduced to the atmospheric pressure is preferably used. .

On the way until the fuel supply pipe 6 reaches the mixer 7, the storage chamber 12 is connected to a portion inserted into the engine chamber 21,
Here, the fuel gas is temporarily stored. The storage chamber 12 is formed of a metal plate having good heat conductivity such as a steel plate or a brass plate as an outer shell, so that the fuel gas in the storage chamber can exchange heat with the atmosphere in the engine room 21 in a good manner.

On the other hand, the intake air is introduced into an air cleaner 8 installed in an engine room 21, and after being cleaned there, is introduced into a mixer 7 through an air supply pipe 9. The fuel gas and the intake air are mixed at a predetermined mixing ratio by a mixer 7, supplied as a mixture to the gas engine 1, and drive the gas engine 1 by performing combustion. Exhaust gas exhausted from the exhaust pipe 10 is supplied to a silencer 11 to be silenced.

Reference numeral 13 denotes an outdoor heat exchanger constituting the outdoor unit II of the air conditioner, and reference numeral 14 denotes a fan for promoting the heat exchange.

FIG. 3 shows an example of an air conditioning system incorporating the gas engine.

A discharge pipe 34 and a suction pipe 35 for the refrigerant are connected to the compressor 3 driven by the gas engine 1. A four-way switching valve 36 is connected between the discharge pipe 34 and the suction pipe 35. Further, pipes 37 and 38 extending from the four-way switching valve 36 have one pipe 37
Is connected to the outdoor heat exchanger 13 having the fan 14 attached thereto, and the other pipe 38 is connected to the indoor heat exchanger 42 constituting the indoor unit III.
Is connected. Further, between a pipe 43 extending from the outdoor heat exchanger 13 and a pipe 44 extending from the indoor heat exchanger 42, a heating expansion valve 45, a cooling expansion valve 46, check valves 47 and 48,
A receiver 49 and the like are connected.

In such a refrigerant circuit, when the four-way switching valve 36 is switched so that the refrigerant circulates in the direction of the solid line arrow, the outdoor heat exchanger 13 functions as a vaporizer, while the indoor heat exchanger
42 functions as a condenser and forms a heating circuit. Also,
When the refrigerant is switched to circulate in the direction of the dashed arrow, the outdoor heat exchanger 13 acts as a condenser and the indoor heat exchanger 42 acts as a vaporizer to form a cooling circuit, contrary to the above.

In this air conditioner, a jacket 53 is provided inside the muffler 11 together with an engine cooling water jacket 51 provided in the gas engine 1. In these jackets 51 and 53, the engine cooling water is forcibly circulated by a pump 50 and heat-exchanged, then further forcibly circulated and divided into two by electromagnetic valves 57 and 58, and one of them is supplied to an outdoor heat exchanger 59. Thus, the outdoor heat exchanger 13 is used for defrosting, and the other is supplied to the indoor heat exchanger 60 to be used for heating.

In such an air conditioner, in order to operate the room at a constant temperature range by the thermo-on / off control, the gas engine 1 is operated when the room temperature rises to a predetermined temperature range.
Is stopped, and is started again when the temperature falls out of the temperature range, and is repeated.

In the gas engine 1 of the present invention, when the above-described air conditioner is restarted during operation, that is, when hot start is performed, the temperature of the fuel gas and the intake air is adjusted as follows, and the 7. That is, since the fuel gas has the storage chamber 12 at the portion where the supply pipe 6 is inserted into the engine chamber 21, when the gas engine 1 stops, the fuel gas is temporarily stored in the storage chamber 12. In the state, heat exchange is performed with the atmosphere in the engine room 21, and the temperature becomes equal to the atmosphere. On the other hand, the intake air is
Is provided in the engine room 1 and is temporarily stored therein, and heat exchange is performed with the atmosphere in the engine room 21 to reach the same temperature as in the case of the fuel gas.

Therefore, when the gas engine 1 in the warmed-up state is restarted, the fuel gas and the intake air having the same temperature as the atmosphere in the engine room 21 are supplied to the mixer 7 as described above. Therefore, the gas mixture is formed so as to be mixed as set in the mixer 7, so that the gas engine can be started in a short time and reliably.

In order to perform such a reliable start, it is most preferable that the engine is provided with the fuel gas storage chamber 12 in the engine chamber 21 as in the embodiment of FIGS. However, in the present invention, the storage chamber 12 may be housed in the space room 22 adjacent to the engine room 21, as in the embodiment shown in FIGS. Since the temperature of the space chamber 22 becomes considerably high due to the heat conduction from the engine room 21, a hot start substantially similar to that of the embodiment shown in FIGS. 1 and 2 can be performed.

〔The invention's effect〕

As described above, the fuel supply device of the present invention provides, in a gas engine housed in an engine room, an air cleaner housed in an engine room, and a storage chamber for temporarily storing fuel gas in a fuel gas supply line, Since the storage chamber is housed in the engine room or a space room adjacent to the engine room, the temperature of the fuel gas and the temperature of the intake air at the time of hot start can be made equal. Therefore, the mixture ratio of the intake air-fuel mixture at the time of the first explosion can be easily controlled, and the hot start of the gas engine can be reliably performed in a short time.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a partial section of a unit portion of a gas engine of the present invention applied to an air conditioner, FIG. 2 is a side view schematically showing the left side, and FIG. FIG. 4 is a system diagram of an air conditioner, FIG. 4 is a front view schematically showing a partial section of an engine unit according to another embodiment, and FIG. 5 is a side view schematically showing the left side. 1 ... gas engine, 5 ... zero governor, 6 ... fuel supply pipe, 7 ... mixer, 8 ... air cleaner, 9 ... air supply pipe, 12 ... storage chamber, 20 ... soundproofing material, 21 ... Engine room, 22 …… A space room (adjacent to the engine room).

Claims (1)

(57) [Claims] 1. A gas engine which is housed in an engine room and is operated by a mixture of fuel gas adjusted by a zero governor and air purified by an air cleaner, wherein said air cleaner is housed in said engine room, A fuel supply device for a gas engine, wherein a storage chamber for temporarily storing fuel gas is provided in the middle of a fuel gas supply line, and the storage chamber is housed in the engine room or a space adjacent to the engine room.