JP2000038938A - Operating method and device of dual fuel type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the operating method of the different running areas of a dual fuel type gas engine. SOLUTION: An engine is made into a dual fuel type by attaching a liquid fuel feeding device 24 and a gas fuel feeding device 15, a gas fuel control device 22 is provided to the gas fuel feeding device 15, a liquid fuel control device 23 is provided to the liquid fuel feeding device 24, and an external signal receiver device 21 used commonly to both control devices 22 and 23 is also provided. And the present position is decided depending on an external signal from an artificial satellite and the like, the both control devices 22 and 23 operate the engine by converting controlling in the operation mainly of a gas, and the operation of a light oil excusively, the running mainly of a gas is carried out in a specific area of a town part and the like in order to make in a low exhaust gas level, while the long distance running is realized by a liquid fuel running in the suburbs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for operating a dual fuel engine in which a gaseous fuel supply device and a liquid fuel supply device are provided in an engine so that gaseous fuel and liquid fuel can be used. The present invention relates to a technology that enables a vehicle to run on gaseous fuel and to run on liquid fuel in other regions.

[0002]

2. Description of the Related Art FIG. 4 shows a gas engine using a conventional gaseous fuel, for example, CNG (compressed natural gas) mounted on a vehicle. In this gas engine, air guided by an intake pipe 31 from an air cleaner AC of an intake system is supplied to a supercharger 32.
And is mixed with a gas supplied from a gaseous fuel supply device 45 similar to a carburetor.

A gas fuel supply device 45 has a throttle valve 46 for adjusting the amount of intake pressurized air flowing into the combustion chamber 39,
A gas injector 47 for reducing NG to a predetermined pressure and injecting it into pressurized air, and an emergency shutoff device 48 have a main configuration. A compressed gas container 49 is connected to the emergency shutoff device 48.

The air mixed with CNG by the gas injector 47 flows from the intake manifold 37 into the combustion chamber 39 formed by the cylinder block 40, the head 40a, and the piston 41 through the intake port 38 and the intake valve 38a, and the ignition plug The fuel is ignited at 48, burns, reaches the exhaust manifold 43 via the exhaust valve 42a and the exhaust port 42, and the exhaust energy is recovered by the exhaust turbine 34 of the supercharger 32 and communicates with the exhaust pipe EP.

[0005] Such a gas engine using CNG or a gas engine using LPG has a low C.sub.x including low NOx.
It is recognized as an engine with low O, low HC and low exhaust gas levels. It is well known that the superiority of the exhaust gas is higher than that of a generally used liquid fuel, particularly a diesel engine that uses light oil that is economically used.

However, at this stage, CNG and LP
G has poor fuel economy, few service stations, the weight of gas fuel containers and peripherals, and the large occupied volume.
And the like. Therefore, gas engines are limited to short-distance vehicles such as route buses and garbage trucks in specific areas.

[0007] By mixing a small amount of gas oil having a calorific value of 5% or less with the gas fuel, the ignitability of the gas is improved and the consumption is reduced, and the low polluting exhaust gas level corresponding to the gas fuel is reduced. It is known that it can be secured.

[0008]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned prior art. In a specific area such as a large city, the vehicle is driven mainly by gas fuel having a low exhaust gas level. It is an object of the present invention to provide a method and an apparatus for operating a dual fuel engine for driving a vehicle that travels for a long distance during liquid fuel travel.

[0009]

SUMMARY OF THE INVENTION A method of operating a dual fuel engine according to the present invention is provided with a gaseous fuel supply device and a liquid fuel supply device, and supplies a gaseous fuel (for example, compressed natural gas) and a liquid fuel (for example, light oil). In the method for operating a dual fuel engine configured to be usable, an external signal is received by an external signal receiving device shared by a gas fuel control device provided in the gas fuel supply device and a liquid fuel control device provided in the liquid fuel supply device. A step of selecting either gas-based operation or liquid fuel-only operation based on the received external signal; and, when gas-based operation is selected, gaseous fuel is supplied to the engine and a relatively small amount is supplied. Operating the gaseous fuel control device and the liquid fuel control device so that the liquid fuel is supplied to the engine; Liquid fuel when you select exclusive operation is gaseous fuel supplied to the engine includes the step of operating the gas fuel control apparatus and a liquid fuel control system so as not to be supplied to the engine, and.

The operating device for a dual fuel engine according to the present invention is a dual fuel engine operating device in which a gaseous fuel supply device and a liquid fuel supply device are provided in the engine so that gaseous fuel and liquid fuel can be used. A gas fuel control device is provided in the fuel supply device,
The liquid fuel supply device is provided with a liquid fuel control device, and an external signal receiving device shared by the two control devices is provided, and the control device is operated based on gas or dedicated gas oil operation based on a reception signal of the external signal receiving device. It is characterized in that it is operated by switching control to.

According to the present invention having the above-described configuration, a gas engine is provided with a liquid fuel supply device to form a dual fuel engine, and an external signal receiving device such as a GPS (global positioning system) is used for satellite navigation or the like. Judging the driving area by receiving an external signal, the exhaust gas level is controlled by gas fuel (for example, compressed natural gas) main running in a specific area, and running in long distance by running with liquid fuel such as light oil in other areas. Making it possible.

In practicing the present invention, the liquid fuel supply device is preferably a common rail type injector. With this configuration, in the operation mainly using gaseous fuel, high-pressure injection and a small amount of liquid fuel can be accurately injected into the mixture of gaseous fuel and air, so that the ignitability of gaseous fuel is improved and The consumption of gaseous fuel can be saved and emission levels can be kept low. On the other hand, when the vehicle runs only on liquid fuel such as light oil, the fuel efficiency is higher and the exhaust gas level can be reduced as compared with a general injection pump.

Further, it is preferable that the external signal receiving device is a signal receiving device of a global positioning system (GPS). Unlike the hyperbolic navigation and the sign post method, the use of the GPS has the advantage that its own position can be accurately determined by the satellite navigation without any special equipment on the ground.

Alternatively, the external signal receiving device is preferably a radio wave receiving device (FM) of a navigation system receiving system (VICS). Further, the external signal receiving device is a navigation system receiving system (VICS).
The beacon is also preferred.

In addition to this, according to the present invention, a so-called turbocharger is incorporated by interposing a compressor of a supercharger in an intake pipe and an exhaust turbine of a supercharger in an exhaust pipe. Is preferred.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, a liquid fuel supply device 2 is connected to a CNG gas engine mounted on a vehicle.
4 shows a state in which a dual fuel engine is provided.

In this engine, one end of an intake pipe 1 is connected to an air cleaner AC of an intake system (not shown), and the other end is connected to a compressor 3 of a supercharger 2, and a second air passage 1a and a third The air passage 1b is connected to the intake manifold 7 via the gas fuel supply device 15. Note that the air from the air cleaner AC may be normal intake air that does not pass through the supercharger 2.

The gaseous fuel supply device 15 controls the amount of pressurized air flowing through the second and third air passages 1a and 1b into the combustion chamber 9 and reduces the pressure of CNG to a predetermined pressure. A gas injector 17 for injecting into pressurized air;
The emergency shutoff device 18 is included. And
A compressed gas container 19 is connected to the emergency shutoff device 18. The gaseous fuel supply device 15 is electrically connected to a gaseous fuel control device 22.

The intake manifold 7 includes the cylinder head 1
The combustion chamber 9 is mounted on the intake port 8a of the combustion chamber 9a through the intake valve 8a.
It is connected to the. The combustion chamber 9 is connected to an exhaust manifold 13 mounted on the exhaust port 12 via an exhaust valve 12a, and is connected to the exhaust turbine 4 via a fourth passage 13a.

The common rail type injector 24, which is a liquid fuel supply device, comprises a booster pump, a common rail 26, which is a pressure accumulator, and a light oil injector 30, which is an injection device. The light oil injector 30 is mounted on the cylinder head 10 a so as to inject light oil into the combustion chamber 9, and is connected to the light oil tank 25 via the common rail 26.

A liquid fuel control device 23 is electrically connected to the common rail type injector 24, and a GPS 21 which is an external radio wave receiving device together with the gas fuel control device 22.
It is connected to the.

FIG. 2 schematically shows the relationship among the external signal transmitting base S, the vehicle position, and the specific area. As the receiving function,
For example, a plurality of artificial satellites S from the external signal transmission base S
1 from the GPS 2 attached to the traveling vehicle T
1 to determine whether the current location is a suburban K or a specific area C. Then, the fuel supplied to the engine is determined depending on the traveling area, whether the fuel is mainly gas or only light oil, and the gas fuel control device 22 and the liquid fuel control device 23 instruct the fuel supply devices 15 and 24. Reference symbol S2 indicates a terrestrial transmission base in place of the artificial satellite S1. Here, the symbol FS is a CNG stand,
It is for charging in consideration of the remaining gas amount during running.

First, the combustion operation of the engine will be described with respect to the above configuration, and then the method of operating the dual fuel gas and gas oil will be described. The air guided from the air cleaner AC is pressurized by the compressor 3 of the supercharger 2, merges with the gas ejected from the gas injector 17 in the second air passage 1 b, and enters the intake manifold 7. Here, the amount of gas ejected from the gas injector 17 is controlled by the gaseous fuel control device 22, and the amount of ejected fuel gas is configured to vary widely from 0 to 100% by the control.

The air mixed with CNG by the gas injector 17 flows from the intake manifold 7 through the intake port 8 and the intake valve 8a to the cylinder block 10 and the head 10a.
And into the combustion chamber 39 formed by the piston 41.
On the other hand, light oil is also injected into the combustion chamber from the injector 30, which is a fuel injection device.

As described above, the gas and light oil are supplied to the combustion chamber, and the supply ratio is determined by the gas fuel control device 22 and the liquid fuel control device 23 depending on the region where the vehicle travels, as described later.

The exhaust gas combusted in the combustion chamber 9 passes through the exhaust manifold 13, is recovered in energy by the exhaust turbine 4, and is discharged to the exhaust pipe EP.

Next, the dual fuel operation method will be described with reference to the flowchart of FIG. In step S1, the vehicle travels at a low exhaust gas level (hereinafter referred to as "low
x running ". ) Is determined. That is, GP
In S21, if the current position is a specific area C such as an urban area, low NOx driving is performed, and in suburban K, normal driving using light oil is performed. If it is a low NOx traveling instruction (Yes in step S1), the vehicle is driven mainly by gas in step S3. In this case, a small amount of light oil having a calorific value ratio of 5% or less is injected into the combustion chamber 9 and the engine is driven mainly by gas to run. As an operation point, the injection amount of the light oil injector 30, which is a liquid injector, is reduced, and the gas injector 17 is opened.

If it is not a low NOx traveling instruction (step S
(No at 2) In step S2, the light oil injector 30 is opened, the gas injector 17 is closed, and the vehicle travels only with diesel oil, so to speak.

In step S4, the gas holding amount is confirmed. If there is a predetermined amount of gas in the compressed gas container 19 (step S4 is NO), the previous steps S1 to S3 are continued. On the other hand, a gas shortage state (Yes in step S4)
Then, go to step S5.

In step S5, since the gas cannot be supplied, the gas oil injector 30 is opened and the gas injector is closed, and the diesel operation is performed using only the light oil as in step S2.

In step S6, the fuel supply during traveling is recorded. Since the recording is performed in the state of step S5, the usage status of light oil is recorded in a time series. Therefore, gas other than light oil is used, and the fuel used can be clearly determined. Step S
When Step 6 is completed, the process returns to Step S4.

In the illustrated embodiment, the external signal receiving device is exemplified by a signal receiving device of a global positioning system (GPS). However, the external signal receiving device is not limited to the GPS, but a radio wave receiving device (F) of a navigation system receiving system (VICS).
M) or a navigation system receiving system (VICS) beacon.

[0033]

The effects of the present invention are listed below. (1) A liquid fuel supply device is attached to a gas engine to convert it to dual fuel, and a long-distance driving is performed with low-pollution gas driving in urban areas and light oil driving in suburbs using an external signal receiving device such as GPS. To enable low-pollution running and oil-free long-distance running. (2) If the liquid fuel supply device is a common rail type injector, a high-pressure injection can perform a minute amount of injection with high accuracy, and the fuel consumption can be improved over the entire injection amount to reduce exhaust pollution. (3) If the external signal receiving device is a GPS, it is possible to easily and accurately determine its own position at a lower cost than hyperbolic navigation or sign post navigation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a method and an apparatus for operating a dual fuel engine according to the present invention.

FIG. 2 is an explanatory diagram of the use of radio navigation to determine the recognition of a traveling position.

FIG. 3 is a flowchart for explaining the operation of FIG. 1;

FIG. 4 is a block diagram showing a conventional gas engine.

[Explanation of symbols]

AC ... air cleaner EP ... exhaust pipe C ... urban area K ... suburban area S ... radio navigation transmission base S1 ... artificial satellite S2 ... transmission station GP ... GPS FS ... gas fuel station 1 ... ..Intake pipe 2 ... supercharger 3 ... compressor 4 ... exhaust turbine 7 ... intake manifold 8 ... intake port 8a ... intake valve 9 ... combustion chamber 10 ... cylinder block 11. Piston 12. Exhaust port 12a. Exhaust valve 13. Exhaust manifold 15. Gas fuel supply device 16. Throttle valve 17. Gas injector 18. Emergency shut-off valve 19. Compressed gas container 21.・ External radio wave receiving device, GPS 22 ・ ・ Gas fuel control device 23 ・ ・ Liquid fuel control device 24 ・ ・ Liquid fuel supply device, common rail type injector 25 ・ ・ Light oil tank 26 ・ ・Monreru 30 ... diesel fuel injector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme coat ゛ (Reference) G01C 21/00 G01C 21/00 A F-term (Reference) 2F029 AA02 AB07 AC02 AC12 3G066 AA07 AA11 AB02 AB05 AB06 AC09 BA25 CE21 DC25 DC26 3G092 AA02 AA05 AA06 AA18 AB03 AB06 AB12 BB13 BB20 DC03 DE03S DE04S EA11 EA14 FA15 HB05X HB05Z HG04Z 3G093 AB01 AB02 BA20 BA26 CB00 DB18 EA05

Claims (6)

[Claims] 1. A method for operating a dual fuel engine in which an engine is provided with a gaseous fuel supply device and a liquid fuel supply device so that gaseous fuel and liquid fuel can be used, the gaseous fuel control device provided in the gaseous fuel supply device Receiving an external signal by an external signal receiving device shared with a liquid fuel control device provided in the liquid fuel supply device, and performing either gas-based operation or liquid fuel-only operation based on the received external signal. Selecting and operating the gaseous fuel control device and the liquid fuel control device such that gaseous fuel is supplied to the engine and a relatively small amount of liquid fuel is supplied to the engine when gas-based operation is selected. When the liquid fuel exclusive operation is selected, the liquid fuel is supplied to the engine but the gaseous fuel is not supplied to the engine. Operating the gas fuel control device and the liquid fuel control device. 2. An operating device for a dual fuel engine in which an engine is provided with a gaseous fuel supply device and a liquid fuel supply device so that gaseous fuel and liquid fuel can be used, wherein the gaseous fuel supply device is provided with a gaseous fuel control device. ,
The liquid fuel supply device is provided with a liquid fuel control device, and an external signal receiving device shared by the two control devices is provided, and the control device is operated based on gas or dedicated gas oil operation based on a reception signal of the external signal receiving device. An operating device for a dual-fuel engine, wherein the operating device is controlled by switching to a different mode. 3. The operating device for a dual fuel engine according to claim 2, wherein the liquid fuel supply device is a common rail type injector. 4. The operating device for a dual fuel engine according to claim 2, wherein the external signal receiving device is a signal receiving device for a global positioning system. 5. The dual fuel engine operating device according to claim 2, wherein the external signal receiving device is a radio wave receiving device of a navigation system receiving system. 6. The dual fuel engine operating device according to claim 2, wherein the external signal receiving device is a navigation system receiving beacon.