KR960003253B1 - Fuel feeding device for a gas engine - Google Patents

Abstract

The device for controlling the pressure of fuel supplied to the gas fuel feeder with multiple steps and supplying the proper quantity of the fuel, comprises the pressure regulator(100) for controlling the fuel pressure, provided between the pipelines having the fuel tank(10) and fuel injector(21); spring assembly(120) mounted between the upper and the lower spring seats(130)(131) on the diaphragm(110) in the pressure regulator; actuator(140) for controlling the elasticity of the spring seat(130); ECU(70) for transmitting the signal to the actuator according to the necessary fuel results in order to control the position of the actuator with multiple steps.

Description

Fuel supply device for gas engine

1 is a structural diagram of a pressure regulator for a conventional gas engine.

2 is a structural diagram of a multi-stage pressure regulator for a gas engine according to an embodiment of the present invention.

3 is a fuel supply system diagram of a central fuel supply method for a gas engine according to an embodiment of the present invention.

4 is a fuel supply system of a fuel supply system for each gas cylinder according to an embodiment of the present invention.

5 is a load-flow diagram of a gas engine.

6 is a pressure-flow diagram of a gas engine.

* Explanation of symbols for main parts of the drawings

10: fuel tank 11: fuel cut off side

20: feeder 21: fuel injection

30: suction flow meter 31: air fuel mixer

40: engine 41: crank angle and top dead center detection sensor

51 exhaust gas sensor 52 exhaust three-way catalyst

60: accelerator position detection sensor 70: electronic control unit

100: pressure regulator 110: diaphragm

120: spring combination 130,131: upper and lower spring seat

140: actuator

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 to adjust the pressure of the fuel supplied to the gas fuel supply device in multiple stages to supply a fuel amount suitable for an operating state.

In general, the gas engine has a larger volume of fuel per output than the gasoline engine or diesel engine, since the fuel used is gas. For example, under the premise of obtaining the same calorific value, a gas engine using compressed natural gas had to supply a gas equivalent to about 700 times more volume than a diesel engine using diesel oil.

This volume characteristic implies that the supply quantity control is not easy, and as shown in FIG. 5, it can be seen that the volume range to be controlled in actual engine operation from idling to rated power is wide. .

In addition, Figure 6 is a diagram showing the relationship between the flow rate and the pressure, it can be seen that the pressure change and the flow rate is in close relationship with each other.

On the other hand, the supply amount control method of the conventional fuel supply device for gas engines is known as the flow path area control method which controls the fuel amount by adjusting the flow path area of a fuel, and the method of controlling the flow volume by adjusting the drive time of a fuel injector.

To explain the control principle, while the flow area control method is to increase or decrease the amount of fuel supplied by expanding or reducing the cross-sectional area of the flow path through the fuel injector, by adjusting the driving time of the fuel injector injecting fuel directly into the combustion chamber. The driving time control method is to increase or decrease the amount of fuel.

On the other hand, the conventional methods as described above cause a variety of problems by installing a pressure regulator to determine the pressure of the fuel on the pipeline that is commonly supplied to the fuel injector.

First, in the case of the former flow path area control method, the flow rate is accurately controlled only by controlling the area under a constant pressure. Therefore, the fuel supply system is complicated and the price increases due to the contrary. The problem of unstable driving (hunting) was also caused.

In addition, in the latter driving time control method, since a single fuel injector cannot control the above-mentioned wide volume range, several fuel injectors are used. This causes the same problem as the flow path area control method.

The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a fuel supply device for a gas engine having a simple structure capable of accurately remotely controlling the supply pressure of the fuel through the fuel injector and its injection amount. will be.

The present invention is characterized by comprising a plurality of springs acting on the diaphragm of the pressure regulator, while adjusting the distance between the upper and lower spring seats by a remotely controlled actuator.

Hereinafter, the fuel supply apparatus of the present invention will be described in detail with reference to the accompanying drawings.

1 is a structure diagram of a conventional pressure regulator in contrast to the present invention, wherein the lower spring seat 2 'is in close contact with the diaphragm 11, while the upper spring seat 2 is positioned by the adjusting screw 4. It is to be decided. Therefore, the fuel supplied to the fuel injector via the pressure regulator has a pressure corresponding to the displacement amount of the spring 3 due to the rise of the diaphragm 1 and the lower spring seat 2 '. That is, the pressure of the feed fuel is limited to a constant value depending on the fixed position of the adjusting screw 4.

As mentioned above, the problem caused by the constant pressure of the feed fuel was mentioned above.

2 is a structural diagram of the pressure regulator 100 of the embodiment of the present invention, the spring combination 120 consisting of a plurality of springs between the upper and lower spring seats 130, 131 installed on the upper side of the diaphragm 110. The installation of the upper spring seat 130 is installed such that the setting position is adjusted in multiple stages by the actuator 140 under the control of the electronic control unit 70 described below. At this time, some of the plurality of springs have a suitable gap with the upper spring sheet 130, which is, between the upper and lower spring seats 130, 131 during the movement of the upper spring sheet 130 by the actuator 140. It is to control the supply pressure of the fuel more precisely by adjusting the spring number that is constrained in the spring constant.

The spring combination 120 is preferably arranged coaxially with a cylindrical spring having a different diameter.

3 and 4 illustrate the fuel supply system of the embodiment of the present invention in which the pressure regulator 100 of FIG. 2 is mounted, and the operation principle of the fuel supply system of FIG.

A pressure regulator 100 is installed between the fuel shutoff side 11 installed in the supply line of the gas fuel tank 10 and the feeder 20 having a plurality of fuel injectors 21, and the feeder 20 is a suction flow meter. 30 is connected to the intake port of the engine 40 through the intake throttle 32 connected to the feed fuel mixer 31 and the accelerator position detection sensor 60, the exhaust recirculation control valve 50, the exhaust oxygen In the configuration in which the sensor 51 and the exhaust ternary catalyst 52 are connected to the exhaust port of the engine, each of the above elements is controlled by the electronic control unit 70.

First, the fuel requirement is determined by the accelerator position detection sensor 60 and the suction flowmeter 30, and the actuator 140 is operated by the signal of the electronic control unit 16 to supply the fuel supply pressure through the pressure regulator. This is determined.

The pressure regulator 100 operates to increase the fuel pressure that is passed when the amount of fuel required by the engine is large and to lower the fuel pressure that is passed when the fuel demand, such as idle or no load, is small.

Therefore, since the pressure formed in the pressure regulator 100 of the present invention varies from time to time by a wide range of pressures by the plurality of spring combinations 120 and remote electronic control, the conventional simplicity formed by one spring. It is essentially different from the pressure.

After the supply pressure of the fuel is determined, the precise fuel amount is measured and supplied to the engine by the sequential control of the pigment sprayer and the pulse width modulation technique.

In addition, the electronic control unit 70 adjusts the opening and closing of the exhaust recirculation amount control valve 50 or the pulse width of the fuel injector 21 according to the air fuel ratio detected by the exhaust oxygen sensor 51, and the crank angle. And controlling the operation time of the fuel injector according to the intake valve opening and closing state detected by the top dead center detection sensor 41 to maintain the optimum operation of the engine.

FIG. 4 is a fuel supply method for each cylinder, except that the above control is performed for each cylinder. The operation principle is the same as that of the central fuel supply method of FIG.

That is, in the case of the fuel supply method for each cylinder of a medium-large gas engine, conventionally, two or more fuel injectors were required for each cylinder, whereas in the embodiment of the present invention, it is not only possible to precisely control the air fuel ratio in the pre-operation region with one fuel injector. In addition, unstable operation due to non-uniform air fuel ratio at low speed rotation can be eliminated.

As described above, the present invention simplifies the structure of the fuel supply device for the gas engine and has the effect of allowing accurate flow rate control by electronic control.

Claims (4)

A pressure regulator 100 for controlling the pressure of the fuel supplied and installed between the fuel tank 10 and the conduit of the feeder 20 having the fuel injector 21, and a diaphragm 110 installed inside the pressure regulator. A spring combination 120 interposed between the upper and lower spring seats 130 and 131 of the upper part of the upper side and an actuator 140 installed upward to adjust the restraint force of the upper springist 130. And an electronic control unit 70 which sends a signal to the actuator 140 in accordance with the determination result of the fuel consumption to adjust the position of the actuator in multiple stages. . The fuel supply device for a gas engine according to claim 1, wherein the actuator (140) is remotely controlled by an electronic control unit (70). The fuel supply device for a gas engine according to claim 1, wherein the spring combinations 120 interposed between the upper and lower spring seats 130 and 131 form a plurality of springs in a cylindrical shape and are arranged in parallel. The fuel supply device for a gas engine according to claim 1 or 3, wherein a part of the plurality of springs maintains a proper gap from the upper spring seat (130).