JPH0660758U - Fuel supply device for internal combustion engine using gas fuel - Google Patents

Abstract

(57) [Abstract] [Purpose] The objective is to improve the engine performance and exhaust performance by effectively utilizing the pressure energy of gas fuel. A turbine 15A is installed in a fuel supply passage 13, a compressor 15B driven by the turbine 8A is installed in a branch intake pipe 8A, and a tip nozzle portion of the branch intake pipe 8A is connected to a venturi of a mixer 10. The nozzle portion 13a at the tip of the fuel supply passage 13 is opened in parallel with the nozzle portion 8a at the tip of the branch intake pipe 8A so that the nozzle portion 13a at the tip of the fuel supply passage 13 is opened in the vicinity of the upstream side of the portion in parallel with the flow direction of the air flow from the main intake pipe 8. It has an ejector structure. As a result, the filling energy is improved by utilizing the pressure energy of the gas fuel, so that higher output and lower fuel consumption can be achieved. Further, NOx can be reduced by reducing the combustion temperature by the intake air cooling effect due to the adiabatic expansion of the gas fuel at the time of ejection.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel supply device for an internal combustion engine that uses gas fuel, and more particularly to a technique for effectively utilizing the pressure energy of gas fuel.

[0002]

[Prior art]

 Conventionally, an internal combustion engine using a gas fuel such as CNG (compressed natural gas) or LPG (liquefied petroleum gas) has been proposed (JP-A-3-253748, JP-A-4-103864, JP-A-4). -94443, Japanese Utility Model Laid-Open No. 60-92742, Japanese Patent Application Nos. 4-15723 and 4-15120, etc.).

In an internal combustion engine using such a gas fuel, a cylinder or a tank is filled with the gas fuel at a high pressure, and when the gas fuel is supplied to the engine, the gas fuel is decompressed by a pressure regulating valve and supplied.

[0004]

[Problems to be solved by the device]

 By the way, in this kind of conventional internal combustion engine using gas fuel, there is no one that recovers and effectively utilizes the pressure energy of high-pressure gas fuel. For hydrogen engine vehicles, it has been proposed to use latent heat of vaporization when vaporizing liquid hydrogen as a cold heat source for the refrigeration system (29th Tokyo Motor Show Pamphlet, 1990, Hino Motors Ltd.). Co., Ltd. does not recover the pressure energy of gas fuel.

The present invention has been made in view of the above circumstances, and uses the pressure energy of gas fuel effectively to improve the engine performance and the like. The purpose is to provide a device.

[0006]

Therefore, in the fuel supply device for a gas fuel internal combustion engine of the present invention, the fuel is branched from the upstream intake passage of the mixer interposed in the intake passage and opened near the upstream of the venturi portion of the mixer. A supercharger consisting of a turbine installed in a fuel supply passage that connects the mixer and a gas fuel supply source, and a compressor installed in the branch intake passage and driven by the turbine. While the machine is installed, the nozzle portion at the tip of the branch intake passage opening near the upstream of the venturi portion is made parallel to the flow direction of the air flowing into the mixer, and the nozzle portion at the tip of the fuel supply passage is connected to the branch intake passage. The ejector section was formed so as to face the nozzle section parallel to the air flow direction.

[0007]

[Action]

 In such a configuration, the turbine of the supercharger is driven by the high-pressure gas fuel from the fuel supply source, whereby the intake air supercharged by the compressor in the branch intake passage is supplied to the mixer. Further, when the gas fuel is ejected from the nozzle portion at the tip of the fuel supply passage, it is decompressed and accelerated, and the ejector action accelerates the intake air in the branch intake passage. When ejected from the section, the intake air from the main intake passage connected to the upstream side of the mixer is sucked and accelerated.

Therefore, the charging efficiency of the intake air is improved. Further, since the intake air temperature is lowered by the latent heat of vaporization due to the adiabatic expansion of the gas fuel at the time of jetting, the charging efficiency is further improved. Further, the combustion temperature is reduced to have the NOx reduction effect, knocking is less likely to occur, the compression ratio can be set high, and high output and low fuel consumption can be achieved.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1 showing the overall configuration of the internal combustion engine using gas fuel of the present embodiment, an exhaust manifold 2 is connected to an engine body 1, and an exhaust pipe 3 connected to the exhaust manifold 2 is connected to an exhaust gas of an exhaust turbocharger 4. A turbine 4A, a catalyst 5 and an exhaust muffler 6 are sequentially provided. On the other hand, an air cleaner 9, an intake compressor 4B of the exhaust turbocharger 4, a mixer 10 and a throttle valve 11 (shown in FIG. 2) are interposed in an intake pipe 8 connected to an intake manifold 7 connected to the engine body 1. There is. Further, the intake pipe 8 is provided with a branch intake pipe 8A as a branch intake passage which branches from the upstream side of the intake compressor 4B and opens near the venturi portion 21 (shown in FIG. 2) of the mixer 10. There is.

The mixer 10 is connected to a fuel supply passage 13 for supplying gas fuel from, for example, a fuel tank 12 as a fuel supply source filled with gas fuel. In this fuel supply passage 13, there are provided a pressure regulating valve 14 (which may be a metering valve) for reducing the pressure of the gas fuel to a predetermined pressure, and a turbine 15A for driving a compressor 15B provided downstream of the pressure regulating valve 14 in the branch intake pipe 8A. It is installed. The compressor 15B and the turbine 15A constitute a supercharger 15. Reference numeral 16 is an overflow prevention valve mounted on the fuel tank 12.

Both ends of the branch intake pipe 8A and the fuel supply passage 13 are open to the mixer 10 as shown in FIG. That is, the nozzle portion 8a at the front end of the branch intake pipe 8A, which is opened near the upstream of the venturi portion 21 of the mixer 10, is opened so as to face in parallel with the air flow direction flowing from the main intake pipe of the intake pipe 8 into the mixer 10. The nozzle portion 8a of the branch intake pipe 8A is made to face the nozzle portion 13a at the tip of the fuel supply passage 13 in the same direction as the nozzle portion 8a at the tip of the branch intake pipe 8A, that is, in parallel with the air flow direction. The ejector portion 22 is formed.

Next, the operation will be described. When the fuel in the fuel tank 12 passes through the fuel supply passage 13, it is decompressed to some extent by the pressure regulating valve 14 and supplied to the turbine 15A, where the pressure energy of the gas fuel is used to drive the turbine 15A. Then, it is ejected from the nozzle portion 13a at the tip. On the other hand, the air flow sucked into the intake pipe 8 is supercharged by the exhaust turbocharger 4 and supplied to the mixer 10, and a part of the air flow in the branch intake pipe 8A is driven by the turbine 15A. It is supercharged by the compressor 15B and is supplied to the mixer 10 from the branch intake pipe 8A.

Then, the gas fuel and the air flow from the branch intake pipe 8a are decompressed and accelerated when ejected from the respective nozzle portions 13a and 8a, and the main intake air is generated by the ejector action in the ejector portion 22. The air flow from the pipe is sucked and accelerated, mixed in the bench portion 21 of the mixer 10 to form a mixture, and supplied to the combustion chamber of the engine body 1 via the throttle valve 11.

According to the apparatus of the present embodiment, a part of the intake air can be supercharged by using the pressure energy of the gas fuel, and furthermore, the air flowing into the mixer 10 can be accelerated by the ejector action, and the intake charging efficiency η _V Can be improved, and high output and low fuel consumption can be achieved. In addition, the temperature of the air flow can be lowered by the latent heat of vaporization due to adiabatic expansion when the gas fuel is ejected from the nozzle portion 13a, and further, the intake charging efficiency η _V can be improved, and at the same time, the temperature can be lowered. The combustion temperature can be reduced and NOx can be reduced. Moreover, since knocking is less likely to occur and the compression ratio can be increased, the output and the fuel consumption rate can be further improved. Further, in the internal combustion engine with the supercharger as in the present embodiment, the intercooler can be substituted, and the intercooler can be omitted.

In the present embodiment, an example of an internal combustion engine in which an exhaust turbocharger is mounted on the main intake pipe is shown, but it goes without saying that a normal internal combustion engine without an exhaust turbocharger may be used.

[0016]

[Effect of device]

 As described above, according to the present invention, the pressure energy of the high-pressure gas fuel is effectively used to partially supercharge the air flow supplied to the engine, and the air flow is further increased by the ejector structure of the mixer. Can be accelerated, the intake charging efficiency can be improved, and high output and fuel efficiency can be achieved. In addition, the adiabatic expansion during gas fuel injection can cool the air flow, reduce NOx by lowering the combustion temperature, and improve the compression ratio, further increasing the output and fuel efficiency. It is possible to improve the engine operation performance and exhaust performance of a gas fueled engine.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a sectional view showing a mixer applied to the example of the same.

[Explanation of symbols]

 1 Engine Main Body 8 Intake Pipe 8A Branch Intake Pipe 8a Nozzle Part 10 Mixer 12 Fuel Tank 13 Fuel Supply Passage 13a Nozzle Part 15 Supercharger 15A Turbine 15B Compressor 21 Venturi Part 22 Ejector Part

Claims (1)

[Scope of utility model registration request] 1. A fuel supply passage for branching from an upstream intake passage of a mixer interposed in the intake passage and having a branch intake passage opened near a venturi portion of the mixer and for communicating the mixer with a gas fuel supply source. A turbine installed in the
A supercharger including a compressor driven by the turbine and provided in the branch intake passage is provided, and a nozzle portion at the tip of the branch intake passage opening near the upstream of the venturi portion is connected to the air flow direction into the mixer. An internal combustion engine using gas fuel, characterized in that the ejector portion is formed by facing the nozzle portion of the fuel supply passage in parallel with the air flow direction in the nozzle portion of the branch intake passage while facing in parallel. Fuel supply system.