JPH07279772A - Gas engine fuel supply quantity control device - Google Patents

Abstract

PURPOSE:To prevent deterioration of fuel consumption and exhaust gas of the charger device for a gas engine by restraining variation of air-fuel ratio of air-fuel mixture caused by air cleaner clogging. CONSTITUTION:Regarding charging device supplying a gas engine 1 with mixture of air taken in through an air cleaner 22 and fuel fed from a high pressure fuel gas supply source through a pressure reduction device in accordance with the negative pressure of an intake manifold 20, its fuel supply quantity control device is composed so that fuel supply quantity may reduce in conjunction with the increase of negative pressure in the intake manifold 20 produced by reduction of air supply quantity caused by the air cleaner 22 clogging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to air taken in via an air cleaner and fuel gas fed from a high pressure fuel gas supply source via a pressure reducing device in accordance with a negative pressure of an intake manifold. The present invention relates to a fuel supply amount control device in an air supply device which mixes and supplies the gas to a gas engine.

[0002]

2. Description of the Related Art As an air supply device for a gas engine operated by combustion of a mixture of air and fuel gas, an air intake part, a fuel gas supply part provided with a pressure reducing device, air and fuel gas from the air intake part It consists of an intake manifold that sends the fuel gas from the supply unit to the engine as an air-fuel mixture, a mixing unit for air and fuel gas that is provided in the middle of the intake manifold, and an air cleaner is placed in the air intake unit.
The fuel gas supply unit depressurizes the high-pressure gas from the gas supply source and sends the fuel gas to the mixing unit according to the negative pressure of the intake manifold that sends the air-fuel mixture to the engine. It is well known that the device is arranged. (See JP-A-60-140044)

[0003]

By the way, in the conventional gas engine air supply device as described above, clogging occurs in the air cleaner arranged in the air intake portion due to dust and blow-by gas in the atmosphere, and Since the clogging of the air cleaner progresses as the operating time increases, the intake amount of air gradually decreases until the air cleaner is replaced, and the negative pressure of the intake manifold gradually increases accordingly.

On the other hand, since the fuel gas is sent to the mixing portion in accordance with the negative pressure of the intake manifold, the fuel gas is supplied as the intake amount of air decreases and the negative pressure of the intake manifold increases. As a result, the air-fuel mixture sent to the engine becomes richer, but such a change in the air-fuel ratio deteriorates the fuel economy and reduces the amount of N in the exhaust gas.
O _X causes problems such that increase.

An object of the present invention is to eliminate the above-mentioned inconvenience of the conventional air supply device for a gas engine. More specifically, even if the clogging of the air cleaner progresses, the air-fuel mixture can be mixed. It is an object of the present invention to provide a fuel supply amount control device for a gas engine, which can suppress the change in the air-fuel ratio and prevent deterioration of fuel efficiency and exhaust gas.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the object, the present invention uses air taken in through an air cleaner and a high pressure fuel gas supply source through a pressure reducing device. In the air supply device that mixes with the fuel gas fed according to the negative pressure of the intake manifold and supplies it to the gas engine, the fuel supply amount control device is
It is characterized in that the supply amount of the fuel gas is reduced in association with the increase in the negative pressure of the intake manifold caused by the decrease in the air supply amount due to the clogging of the air cleaner.

[0007]

[Operation] With the above configuration, the supply amount of fuel mixed with air decreases as the air supply amount decreases due to the clogging of the air cleaner, and thus the change in the air-fuel ratio of the air-fuel mixture is suppressed. and it does not cause deterioration of exhaust gas due to an increase in degradation and nO _X in fuel consumption.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel supply amount control device for a gas engine of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of an air conditioner which is a combination of a water heater and a heat pump driven by a gas engine, to which an embodiment of a fuel supply control device for a gas engine of the present invention is applied. is there.

In the air conditioner shown in FIG. 1, the compressor 2 is driven by the gas engine 1, and the compressor 2 is driven during cooling.
The working fluid, which has been compressed at a high temperature and is sent to the outdoor heat exchanger 4 by the switching valve 3, is cooled and liquefied by the outdoor heat exchanger 4, then becomes a low pressure through the expansion valve 5, and becomes the indoor heat exchanger. The cycle of vaporizing in 6 to cool the room and then returning to the compressor 2 through the switching valve 3 and the accumulator 7 is repeated. During heating, the working fluid compressed by the compressor 2 and having a high temperature is switched. After being sent to the indoor heat exchanger 6 by the valve 3, the indoor heat exchanger 6 warms the room, the pressure becomes low through the expansion valve 5, and the outdoor heat exchanger 4 vaporizes and expands the heat from the outside air as vaporization latent heat. The cycle of taking in and returning to the compressor 2 through the switching valve 3 and the accumulator 7 is repeated. By circulating the cooling liquid of the gas engine 1 in the water heater 8, the water in the water heater 8 becomes hot water. To do.

The gas engine 1 used in such an air conditioner has a control device 1 whose operating condition is set by a control signal from an operating condition setting device 9 of the air conditioner.
The operation of the control device 10 is controlled by 0, and the control device 10 sends an output signal to the throttle valve opening / closing device 13 and the ignition control device 14 in response to input signals from the engine speed sensor 11 and the intake manifold negative pressure sensor 12 to control the throttle. It controls the valve 15 and the spark plug 16.

FIG. 2 shows an air supply device for supplying a mixture of air and fuel gas in such a gas engine 1. An air cleaner is provided at an end of the intake manifold 20 to take in air. The air intake part 21 is opened via 22 to supply fuel gas,
A fuel gas supply pipe 24 communicating with a venturi portion 23 (a mixture portion of air and fuel gas) provided in the middle of the intake manifold 20 is provided, and the fuel gas supply pipe 24 and a fuel gas supply source (not shown) are provided. A regulator device 30 that supplies the fuel gas to the fuel gas supply pipe 24 in accordance with the negative pressure in the intake manifold 20 is arranged between them.

The regulator device 30 reduces the pressure of the gas supplied from the high-pressure fuel gas supply source to a set pressure, and then supplies the gas in accordance with the negative pressure generated in the air-fuel gas mixing portion. It is a decompressor and automatic pressure regulator called a zero governor for
It is divided into a primary chamber 32 and a secondary chamber 33 by 1.
Further, the primary chamber 32 is defined by a diaphragm 34 into a primary gas chamber 321 and an atmospheric pressure chamber 322, and the secondary chamber 32 is divided by a diaphragm 35 into a secondary gas chamber 331 and an atmospheric pressure chamber 3.
It is defined by 32.

A gas inlet 36 communicating with the fuel gas supply source is opened in the primary gas chamber 321, and the base 31 is opened.
Is provided with a communication hole 37 that communicates the primary gas chamber 321 and the secondary gas chamber 331, and the secondary gas chamber 331 is provided with a gas outlet 38 that communicates with the fuel gas supply pipe 24. One side of the primary chamber 31 has a diaphragm 34 at one end.
And a valve 41 for closing the gas inlet 36 at the other end of the lever 41 is swingably supported by a pin 42. One end of the base plate 31 is engaged with the diaphragm 35 on the secondary chamber side. A valve 43 that closes the communication hole 37 at the other end
A lever 44 provided with is pivotally supported by a pin 45.

In such a regulator device 30, the negative pressure of the venturi portion 23 is the fuel gas supply pipe 24.
When added to the secondary gas chamber 331 through the gas outlet 38, the gas in the secondary gas chamber 331 is sucked into the fuel gas supply pipe 24 through the gas outlet 38, and the internal pressure of the secondary gas chamber 331 decreases.

Then, the valve 43 opens when the following conditions are satisfied. P ₁ S ₁ ≧ P ₂ S ₁ + C ₁ F ₁ −C ₂ F ₂ + C ₂ S ₂ P
_2- C ₂ S ₂ P ₃ Here, P ₁ is the internal pressure of the primary gas chamber 321, S ₁ is the pressure receiving area of the valve 43, P ₂ is the internal pressure of the secondary gas chamber 331, and F ₁
Is the elastic force of the return spring 46a, F ₂ is the elastic force of the spring 46b, and C ₁ and C ₂ are the ratios of the distance from the pin 45 to the valve 43 to the point of action of each force (lever). Ratio), S ₂ is the effective pressure receiving area of the diaphragm, and P ₃ is the internal pressure of the atmospheric pressure chamber 332.

As can be seen, when the internal pressure P ₂ of the secondary gas chamber 331 decreases, the right side of the above inequality becomes smaller and the valve 43 opens. That is, the atmospheric pressure through the air cleaner 22 and the elastic force of the spring 46b are applied against the return spring 46a, and the diaphragm 3
5 is pushed down, the lever 44 rotates and the communication hole 37 closed by the valve 43 opens.

When the valve 43 opens, the primary gas chamber 32
The gas of No. 1 flows into the secondary gas chamber 331 through the communication hole 37, flows out from the gas outlet 38 through the secondary gas chamber 331, while the gas flows into the secondary gas chamber 331,
When the gas pressure in the primary gas chamber 321 drops to a certain level,
The diaphragm 34 is pushed down by the return spring 47, the lever 41 rotates, and the gas inlet 36 that was closed by the valve 40 opens, and the primary gas chamber 32
A gas from a supply source is supplied to the inside of the unit 1.

When the negative pressure in the venturi portion 23 is reduced, the diaphragm 35 of the secondary gas chamber 331 is returned by the return spring 46, the lever 44 is rotated, and the communication hole 37 opened is closed by the valve 43. It

When the valve 43 is closed, the primary gas chamber 32
1 is filled with gas from the supply source and the inside of the primary gas chamber 321 rises to a set pressure, the gas pressure pushes the diaphragm 34 back against the return spring 47, and the lever 41 rotates to open. Gas inlet 36
Is closed by valve 40.

In the air supply device of the gas engine 1 in which the regulator device 30 as described above is arranged, the increase in the negative pressure in the intake manifold 20 caused by the decrease in the air supply amount due to the clogging of the air cleaner 21 is considered. Accordingly, in order to reduce the supply amount of the fuel gas from the fuel gas supply pipe 24, inside the intake manifold 20 downstream of the air cleaner 22 and the secondary chamber 32 of the regulator device 30.
The negative pressure pipe 25 is provided so as to communicate with the atmospheric pressure chamber 332 on the side.

Since the negative pressure pipe 25 is provided between the intake manifold 20 and the regulator device 30 as described above, the negative pressure increased in the intake manifold 20 due to the clogging of the air cleaner 22 is reduced to the negative pressure pipe 2.
5, the diaphragm 35 is added to the atmospheric pressure chamber 332 on the secondary chamber side of the regulator device 30. As a result, the diaphragm 35 is less likely to be pushed down and easily returns, so that the communication hole 37 is less likely to open and the fuel gas supply pipe 24 The amount of fuel gas supplied from the vehicle will decrease.

In this embodiment, in order to make the return spring 46b of the diaphragm 35 adjustable, the return spring 46b is installed via the movable stay 49 rotatable around the pin 51 by the adjusting screw 48. A spring 46c is provided to hold the movable stay 49 against the adjusting screw 48.

In the above embodiment, the regulator device 3
Since the negative pressure pipe 25 is communicated with 0, the intake manifold negative pressure that increases as the clogging of the air cleaner 22 progresses acts on the secondary gas chamber 331 via the diaphragm 35, and the valve 43 is opened. Since the differential pressure at the time of opening the valve (the pressure difference between the primary gas chamber 321 and the secondary gas chamber 331) increases, the valve 43 will not open unless the negative pressure of the venturi portion 23 becomes larger.

Therefore, when the valves 40 and 43 are closed due to the progress of clogging of the air cleaner 22, the pressure of the primary gas chamber 321 is constant, while the pressure of the secondary gas chamber 331 becomes smaller. Therefore, when the valve 43 is once opened, the pressure difference between the primary gas chamber 321 and the secondary gas chamber 331 becomes large, so that the primary gas chamber 321 to the secondary gas chamber 331 can be shortened in a short time.
Fuel gas will be supplied to.

Therefore, the followability of the fuel gas supplied to the venturi portion 23 is improved, and when the throttle valve 15 is rotated in the opening direction, the fuel gas is immediately supplied accordingly, and the air cleaner 22 is supplied. Even if clogs, the effect of improving the followability of the gas engine 1 is not only reduced but improved.

As described above, the fuel supply amount control device of the gas engine of the present invention has the regulator device 30 and the negative pressure pipe 2.
However, the specific structure for controlling the supply amount of the fuel gas according to the change in the intake manifold negative pressure is not limited to the above. However, it can be implemented by other structures.

FIG. 5 shows another embodiment of the fuel supply control device for a gas engine according to the present invention.
Similar to the above embodiment, since it is applied to the air supply device of the gas engine for driving the air conditioner that combines the water heater and the heat pump, for parts other than the fuel supply amount control device, The description is omitted by attaching the same reference numerals.

In the embodiment shown in FIG. 5, the fuel supply amount is controlled by providing the negative pressure pipe 25 in the regulator device 30 in the first embodiment, whereas in the regulator device 30, a negative pressure pipe is used. By installing the gas passage opening correction valve 50 in the middle of the fuel gas supply pipe 24 without providing the pressure pipe 25, based on the signals from the negative pressure sensors 51 and 52 for detecting the change in the negative pressure in the intake manifold. The control device 10 controls the opening of the gas passage opening correction valve 50 to control the fuel supply amount.

In the illustrated embodiment, as a negative pressure sensor for detecting a change in negative pressure in the intake manifold due to clogging of the air cleaner 22, a negative pressure sensor for detecting an operating state of the engine. Besides 12, the negative pressure sensor 51 is provided between the throttle valve 15 and the venturi portion 23, and the negative pressure sensor 52 is provided between the venturi portion 23 and the air cleaner 22, respectively, but such a configuration is not necessarily required. Alternatively, a suitable negative pressure sensor may be used alone or in combination.

The fuel supply amount control device for a gas engine of the present invention has been described above with reference to each embodiment applied to a gas engine for driving an air conditioner.
It is needless to say that the present invention is not limited to such an application, and is applicable to all gas engines in which the fuel supply amount is controlled by the negative pressure of the intake manifold.

[0032]

According to the fuel supply amount control device for a gas engine of the present invention as described above, even if the gas engine is operated for a long period of time and the air cleaner is clogged, the air-fuel ratio of the air-fuel mixture is increased. It is possible to suppress the change in fuel consumption and prevent deterioration of fuel consumption and exhaust gas.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an air conditioner to which an embodiment of a fuel supply amount control device for a gas engine of the present invention is applied.

FIG. 2 is an explanatory diagram showing an embodiment of a fuel supply amount control device for a gas engine of the present invention.

FIG. 3 is a block diagram schematically showing an air conditioner to which another embodiment of the fuel supply amount control device for a gas engine of the present invention is applied.

[Explanation of symbols]

 1 Gas Engine 20 Intake Manifold 22 Air Cleaner 23 Venturi Part (Mixing Part of Air and Fuel Gas) 25 Negative Pressure Pipe 30 Regulator Device (Zero Governor) 50 Gas Pass Opening Correction Valve

Claims (1)

[Claims] 1. A gas engine in which air taken in through an air cleaner and fuel gas fed from a high-pressure fuel gas supply source through a pressure reducing device and fed according to a negative pressure of an intake manifold are mixed. In the air supply device that supplies the fuel gas to the air conditioner, the fuel gas supply amount is reduced in connection with the increase in the negative pressure of the intake manifold caused by the decrease in the air supply amount due to the clogging of the air cleaner. Characteristic gas engine fuel supply control device.