JP2004257334A - Method and apparatus for supplying fuel of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for supplying fuel of an internal combustion engine which can realize a proper burning state coincident with the operating state of the internal combustion engine. <P>SOLUTION: The method for supplying the fuel of the internal combustion engine includes the steps of bringing the fuel into contact with a catalyst in a supercritical state or a subcritical state, and spraying the obtained modified fuel in a combustion chamber. The apparatus for supplying the fuel of the internal combustion engine includes a fuel tank, the combustion chamber, and a fuel spraying means for spraying the fuel in this combustion chamber. The apparatus also includes a supercritical generating means for making the fuel from the fuel tank the supercritical state or the subcritical state, and the catalyst containing a catalytic component for modifying the fuel of the supercritical state or the subcritical state generated by this supercritical generating means. Such a supercritical generating means is disposed between the fuel tank and the fuel spraying means. Such a catalyst is disposed between the supercritical generating means and the combustion chamber, etc. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel supply method and a fuel supply device for an internal combustion engine, and more particularly, to a method and a fuel supply device for supplying a reformed fuel obtained by bringing a fuel into contact with a catalyst in a supercritical or subcritical state. About.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a fuel supply device for an internal combustion engine has been proposed in which a part of fuel is made into a supercritical state to be atomized and injected from a fuel injection valve into a combustion chamber (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-161827
[Problems to be solved by the invention]
However, the combustion state changes depending on the type and properties of the fuel, and as a result, the emission components such as particulate matter (PM) and hydrocarbons (HC) from the internal combustion engine and the emission amount change. There is a problem that purification efficiency may be deteriorated.
[0005]
The present invention has been made in view of such problems of the related art, and an object of the present invention is to provide a fuel supply method and a fuel supply device capable of achieving a suitable combustion state that matches an operation state of an internal combustion engine. Is to provide.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that the above object can be achieved by, for example, bringing the fuel into contact with the catalyst in a supercritical or subcritical state, and have completed the present invention. Was.
[0007]
That is, the fuel supply method for an internal combustion engine of the present invention is a method in which fuel is brought into contact with a catalyst in a supercritical or subcritical state, and the obtained reformed fuel is sprayed into a combustion chamber.
Further, a fuel supply device for an internal combustion engine according to the present invention includes a fuel tank, a combustion chamber, and fuel injection means for spraying fuel into the combustion chamber.
Further, in this fuel supply device, a supercritical generating means for converting the fuel from the fuel tank into a supercritical or subcritical state, and a catalyst for reforming the supercritical or subcritical fuel generated by the supercritical generating means A catalyst containing the component, the supercritical generating means is disposed between the fuel tank and the fuel injection means, and the catalyst is disposed between the supercritical generating means and the combustion chamber. ing.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the fuel supply method for an internal combustion engine according to the present invention will be described in detail. In addition, in this specification, "%" represents a mass percentage unless otherwise specified.
[0009]
As described above, the fuel supply method for an internal combustion engine according to the present invention is a method in which fuel is brought into contact with a catalyst in a supercritical or subcritical state, and the obtained reformed fuel is sprayed into a combustion chamber.
Here, the fuel is not particularly limited as long as it is a hydrocarbon-based fuel, and specific examples thereof include light oil, gasoline, naphthene, and GTL. It should be noted that these mixed fuels can be used, and water and the like can be further mixed within the scope of the present invention.
The “supercritical or subcritical state” refers to a state where the temperature is in the range of 150 to 400 ° C. and the pressure is in the range of 2 to 50 MPa.
Further, the “reformed fuel” refers to a fuel obtained by converting hardly combustible HC species in a fuel component into easily combustible HC species, and specifically, a polycyclic fuel such as naphthene (C ₁₀ H ₁₈ ). Fuels that decompose HC species into monocyclic HC species (C ₆ H ₁₀ ) and olefinic HC species and convert them into HC species that are unlikely to produce PM can be given.
[0010]
By setting the fuel in a supercritical or subcritical state, atomized fuel can be atomized and PM can be reduced.However, when the fuel is set in a supercritical or subcritical state, the combustion in the combustion chamber It is desirable to detect the state and adjust one or both of the temperature and pressure of the fuel based on the detected value. In this case, typically, the temperature of the fuel is set to 200 to 400 ° C. and the pressure is set to 15 to It is further desirable to adjust within the range of 40 MPa.
As a result, it is possible to obtain a more suitable combustion state that matches the variable operating state of the internal combustion engine, and as a result, it is possible to reduce the emission of PM and HC from the internal combustion engine.
[0011]
Further, the above-described catalyst is not particularly limited as long as the fuel in a supercritical or subcritical state can be converted into the above-described reformed fuel by contact, and has one or both of a cracking function and a hydrogenation function. Is desirable.
As a result, supercritical or subcritical fuel can be brought into contact with the catalyst to convert hardly combustible HC species into easily combustible HC species, thereby further effectively reducing PM and HC emissions from the internal combustion engine. it can.
[0012]
Next, a fuel supply device for an internal combustion engine according to the present invention will be described.
As described above, the fuel supply device of the present invention can be used for the fuel supply method of the present invention, and includes a fuel tank, a combustion chamber, a fuel injection unit, a supercritical generation unit, and a catalyst. .
Normally, these units are arranged in the order from the upstream side to the downstream side in the fuel supply path of the internal combustion engine, that is, the fuel tank, the supercritical generation unit, the catalyst, the fuel injection unit, and the combustion chamber. However, it is sufficient for the catalyst to be able to come into contact with the fuel in a supercritical or subcritical state, and after the supercritical generating means in the above order, specifically, in the supercritical generating means, in the combustion chamber, and in the supercritical generating means. What is necessary is just to arrange | position between a combustion chamber and at least one place in fuel injection means.
[0013]
Here, the supercritical generating means has a function of bringing the fuel from the fuel tank into a supercritical or subcritical state, and it is sufficient to have a function of controlling the pressure and temperature of the fuel. A high-pressure pump that can realize a high-pressure state of 5 MPa or more can be used.
For example, the fuel can be brought into a supercritical or subcritical state by utilizing the pressure of a high-pressure pump mounted on recent direct injection gasoline and diesel vehicles.
[0014]
FIG. 1 shows an example in which the fuel supply device of the present invention is applied to a direct-injection 4-cylinder 2.5-liter engine equipped with a common rail system as an internal combustion engine.
In FIG. 1, the fuel supply device includes a fuel tank 1, a high-pressure pump 30, a common rail 40, an injector 20 as an example of a fuel injection unit, and a cylinder 10 as an example of a combustion chamber. In this case, the high-pressure pump 30, the common rail 40, and the distribution pipe 50 cooperate to function as a supercritical generation unit. Further, the injectors 20 are installed in the cylinder heads 60 and are electromagnetically oriented to the respective cylinders 10.
Light oil, which is an example of fuel, is stored in the fuel tank 1. The light oil is brought into a supercritical or subcritical state by a high-pressure pump 30, supplied to the injector 20 via a common rail 40 and a distribution pipe 50, and is supplied to the injector 20. Is sprayed into each cylinder 10.
[0015]
In addition, in the fuel supply device of FIG. 1, the distribution pipe 50 is provided with a pressure regulating valve 52 as an example of a pressure adjusting unit, which can pump the fuel to the injector 20 at an appropriate pressure, and change the supercritical state of the fuel. It can be adjusted. Further, the cylinder head 60 also functions as a temperature adjusting means capable of adjusting the temperature with cooling water, and by adjusting the temperature of the injector 20 disposed therein, the supercritical state of the fuel can be adjusted.
Furthermore, an in-cylinder pressure sensor 12 is installed in the cylinder 10 so that the internal pressure can be detected. The super-critical state of the fuel is controlled in cooperation with the pressure regulating valve 52 and the cylinder head 60, and the Thus, a combustion state in which a rapid pressure change does not occur can be realized. Such control may be performed in accordance with the temperature adjustment and pressure adjustment in the above-described fuel supply method of the present invention.
[0016]
In the fuel supply device of FIG. 1, the catalyst, that is, the catalyst for reforming the fuel in a supercritical or subcritical state, is disposed in the fuel flow path in the injector 20 by plating (see FIG. 2). The piston surface of the cylinder 10 may be plated.
In FIG. 1, an exhaust gas purifying catalyst 70 and a PM collecting means 80 are provided downstream of the above-described fuel supply device, and purify exhaust gas and remove PM.
[0017]
By the way, as the high-pressure pump 30, for example, an engine-driven pump whose discharge pressure can be controlled can be used. However, since this only performs pressurization, the fuel becomes high temperature and high pressure as it is, and Parts can be damaged or broken.
Since the fuel supply device of FIG. 1 includes the pressure regulating valve 52 functioning as pressure adjusting means and the cylinder head 60 functioning as temperature adjusting means, the above-described damage and breakage can be prevented, and the durability can be improved. That is, when the fuel is further pressurized from a supercritical or subcritical state to a high pressure, or when the pressure becomes high due to the increase in the number of moles of the fuel by a catalyst described later, the pressure of the fuel is in a suitable range. When the pressure becomes higher than the pressure, the pressure is reduced by the pressure adjusting means, and the pressure is adjusted to the preferable pressure range described above.
The pressure adjusting means is not particularly limited as long as it can be adjusted to a suitable pressure range. Specifically, the fuel supply path is branched between the supercritical generating means and the fuel injection means and connected to the fuel tank 1. The pressure regulating valve 52 provided in the pressure regulating path to be used can be exemplified (see FIG. 1). Note that the above-described high-pressure pump 30 also functions as pressure adjusting means when the discharge pressure can be controlled.
[0018]
Further, as described above, when the fuel is further pressurized from the supercritical or subcritical state to a high temperature, or when the temperature of the fuel becomes high due to a reaction by a catalyst described later, the temperature of the fuel falls within the above-described preferable range. When the temperature becomes higher than this, it is cooled by a temperature adjusting means such as the cylinder head 60 and adjusted to a suitable pressure range.
[0019]
Here, FIG. 2 shows a simplified schematic structure diagram of the injector and a schematic configuration diagram of the portion thereof. As shown in the figure, the fuel sent through the fuel flow path 22 in the fuel injection device is reformed by the catalyst 24 disposed in the fuel flow path and is injected from the injection hole 26.
[0020]
The catalyst is desirably arranged in the fuel injection means by plating the catalyst component. Compared with the other cases described above, that is, compared with the case where the catalyst is disposed between the supercritical generating means and the combustion chamber and in the supercritical generating means, the number of times of contact between the fuel and the catalyst increases because the flow path is narrower, It is thought that sufficient reforming can be performed.
Further, when the temperature becomes high due to a fuel reforming reaction by a catalyst or the like, the temperature can be quickly adjusted to a suitable temperature range by the above-described temperature adjusting means.
By plating the catalyst component as described above, the catalyst can be disposed in a suitable state on a fuel injection means such as an injector having a precise structure.
[0021]
The catalyst components of such catalysts include rhodium (Rh), nickel (Ni), platinum (Pt), palladium (Pd), ruthenium (Ru), copper (Cu), cobalt (Co) or iron (Fe) and any of these. It is desirable that the metal be a combination of the metals.
When the fuel is brought into a supercritical or subcritical state at a high temperature and a high pressure, for example, the above-described naphthene may generate aromatic HC by dehydrogenation in addition to ring-opening decomposition. Is activated by dissociating a hydrogen molecule and is active in hydrogenation. Thus, it is considered that the generated aromatic HC quickly reacts with hydrogen, and the ring-opening decomposition reaction of naphthene proceeds as a whole.
[0022]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
[0023]
(Example 1)
In the fuel supply device shown in FIGS. 1 and 2, the fuel supply device of this example was manufactured by plating the injector 20 with Pt, which is a catalyst component of the catalyst.
[0024]
(Comparative Example 1)
A fuel supply device for an internal combustion engine according to the present example was manufactured using the same configuration as in Example 1 except that the catalyst component of the catalyst was not plated on the injector 20.
[0025]
[Performance evaluation]
Using the fuel supply device of each example described above, the emission amounts of PM, HC and NOx were measured by changing the fuel injection timing under the following conditions. FIG. 3 shows the results obtained by plotting the measured values. The plot of the related art is a case where the catalyst is not used (Comparative Example 1), and the plot of the present example is a case where the catalyst is used (Example 1).
(Performance evaluation conditions)
・ Engine Direct injection 4-cylinder ・ 2.5L diesel engine ・ Maximum torque 250Nm / 2000rpm
・ Fuel Base fuel (JIS II light oil)
・ Fuel reforming catalyst Pt (Plating treatment of injector)
[0026]
From FIG. 3, it can be seen that the examples belonging to the scope of the present invention have lower PM, HC and NOx emissions than the comparative examples other than the present invention. It can be seen that fuel capable of obtaining the preferred combustion state is supplied.
[0027]
As described above, the present invention has been described in detail with reference to the examples. However, the present invention is not limited to these examples, and various modifications can be made within the scope of the present invention.
For example, in the above embodiment, a diesel engine has been described as an example. However, the fuel supply device for an internal combustion engine of the present invention is not limited to this. It can also be used for engines and internal combustion engines that are not vehicles.
[0028]
【The invention's effect】
As described above, according to the present invention, since the fuel is brought into contact with the catalyst in a supercritical or subcritical state or the like, a fuel supply method capable of realizing a suitable combustion state that matches the operating state of the internal combustion engine and A sticky note that can provide a fuel supply device.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an example of a fuel supply device of the present invention.
FIG. 2 is an enlarged cross-sectional view showing a schematic structure diagram and a schematic configuration of an injector.
FIG. 3 is a graph showing exhaust component emission amounts when the fuel supply device of each example is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fuel tank 10 Combustion chamber 12 In-cylinder pressure sensor 20 Fuel injection device 22 Fuel flow path 24 Catalyst 26 Injection hole 30 High pressure pump 40 Common rail 50 High pressure distribution pipe 52 Pressure regulating valve 60 Cylinder head 70 Exhaust gas purification catalyst 80 PM collecting means

Claims (9)

A fuel supply method for an internal combustion engine, comprising bringing a fuel into contact with a catalyst in a supercritical or subcritical state, and spraying the obtained reformed fuel into a combustion chamber. 2. The fuel in a supercritical or subcritical state by detecting a combustion state in the combustion chamber and adjusting the temperature and pressure of the fuel based on the detected value. A fuel supply method for an internal combustion engine according to the above. The method according to claim 1 or 2, wherein the catalyst has a cracking function and / or a hydrogenation function. The fuel supply method for an internal combustion engine according to any one of claims 1 to 3, wherein the temperature of the fuel is adjusted to 150 to 500C and the pressure is adjusted to 2 to 100 MPa. In a fuel supply device for an internal combustion engine including a fuel tank, a combustion chamber, and fuel injection means for spraying fuel into the combustion chamber,
Supercritical generating means for converting the fuel from the fuel tank to a supercritical or subcritical state, and a catalyst containing a catalyst component for reforming the supercritical or subcritical fuel generated by the supercritical generating means,
The supercritical generating means is disposed between the fuel tank and the fuel injection means, and the catalyst is provided between the supercritical generating means and the combustion chamber, in the supercritical generating means, in the combustion chamber and A fuel supply device for an internal combustion engine, wherein the fuel supply device is disposed at at least one position in the fuel injection means. 6. The fuel supply device for an internal combustion engine according to claim 5, further comprising pressure detection means for detecting the pressure of the combustion chamber and temperature detection means for detecting a temperature. The supercritical or subcritical state is generated by the supercritical generating means, and the pressure regulating means for regulating the pressure of the fuel and the temperature regulating means for regulating the temperature are provided. Fuel supply device for internal combustion engines. The fuel supply device for an internal combustion engine according to any one of claims 5 to 7, wherein the catalyst is disposed in the fuel injection means by plating a catalyst component thereof. 9. The catalyst according to claim 5, wherein the catalyst component is at least one metal selected from the group consisting of rhodium, nickel, platinum, palladium, ruthenium, copper, cobalt and iron. 3. A fuel supply device for an internal combustion engine according to claim 1.

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