JPS6048631B2 - Internal combustion engine using catalytic surface reaction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine, and more particularly to a novel internal combustion engine that utilizes catalytic surface reactions.

BACKGROUND ART In conventional internal combustion engines, a fuel mixture in a cylinder is ignited by a spark or compression ignited to cause a chemical reaction in a gas phase reaction, and the heat generated by this reaction is used to generate power.

However, depending on the type of fuel and the fuel supply system, it may be inappropriate to use the conventional internal combustion engine. For example, recently, it has been considered to use hydrogen as a fuel from the perspective of pollution prevention and new resource development, but when hydrogen is subjected to a gas phase reaction in a conventional internal combustion engine, the reaction speed is extremely fast; Extracting energy from a reaction as mechanical power involves a large amount of thermodynamic loss and is also problematic in terms of pollution generation. In addition, recently, it has been considered that hydrogen can be delivered from a storage base to each home through a pipeline, and each home that receives the fuel can obtain power. Due to its explosive nature, equipment to ensure safety must be considerably expensive, and furthermore, it is extremely difficult to put it into practical use. This invention was made in view of the above circumstances, and it is possible to control the reaction rate of a fuel such as hydrogen, which has an extremely high chemical reaction rate, as desired, and without the risk of explosion, making it easy and safe to use at home etc. The purpose is to provide a new internal combustion engine that can be used in Corresponding to this purpose, the internal combustion engine utilizing the catalytic surface reaction of the present invention includes a catalyst disposed in the combustion chamber, and a reactive mixture in which the concentration of the reactive substance is below the flammable limit that does not cause a gas phase reaction. The present invention is characterized in that air is caused to pass through an area affected by the catalyst, and a chemical reaction is caused by a surface reaction using the catalyst to generate heat.

The details of this invention will be explained below with reference to the drawings showing one embodiment.

In FIG. 1, reference numeral 1 denotes an internal combustion engine according to an embodiment of the present invention, and the internal combustion engine 1 includes a cylinder 2. As shown in FIG.

The cylinder 2 has an air-permeable catalyst holding part 3 in the center, and on both sides of the catalyst holding part 3, an intake port 5 is opened and closed by an intake valve 4, and an exhaust port 5 is opened and closed by an exhaust valve 6. An exhaust port 7 is formed. Further, a pair of pistons 8 and 9 are fitted in the cylinder 2 airtightly and slidably with the catalyst holding portion 3 in between. A catalyst 11 is in the catalyst holding part 3.
The gate is kept. The catalyst 11 is made of platinum or other catalytic metal, and has thin wires formed into a spiral shape or a mesh shape. There are no particular restrictions on the shape of the catalyst 11, but it must be configured to have air permeability.
and 13 communicate with each other through a gap in the catalyst 11.
The fuel used in this internal combustion engine is reactive substances such as hydrogen and methane, but particular attention should be paid to the concentration of the air-fuel mixture, which must be below the flammable limit that does not cause gas phase reactions. It is necessary to have a low concentration of
When hydrogen is used as fuel, the hydrogen concentration of the mixed gas with air depends on the shape of the container, but is set to a molar concentration of about 4%, for example.

The air-fuel mixture is supplied to the spaces 12 and 13 through the intake pipe 14, and the exhaust gas in the spaces 12 and 13 is exhausted through the exhaust pipe 15. The air-fuel mixture and the exhaust gas exchange heat in the heat exchanger 16. Next, the operation of the above internal combustion engine will be explained with reference to FIG.

First, when the two pistons 8 and 9 approach each other with the catalyst holding part 3 in between, when the piston 8 moves in the direction shown by the arrow 17, the intake valve 4 opens and the mixed gas enters the space through the intake port 5 (the first Figure 2a). When the piston 8 reaches the bottom dead center, the intake valve 5 closes, and the piston 8 reverses and moves in the direction of the arrow 18.

Then, by moving the piston 8, the gas is further adiabatically compressed to raise its temperature (FIG. 2b), and by further pulling the piston 9 in the direction of the arrow 19, it is expanded isothermally. (Figure 2c). At this time, as the pistons 8 and 9 move, the mixed gas between the two pistons 8 and 9 sequentially contacts the catalyst 11, and only the contacted portion undergoes a chemical reaction due to a surface reaction and generates heat. Since the fuel in the mixed gas has a concentration lower than the flammability limit that causes a gas phase reaction as described above, only the part in contact with the catalyst 11 generates heat, and the reaction propagates to other parts of the mixture. Never. The piston 8 ends its forward movement at the top dead center nearest to the catalyst holding part 3, but the piston 9 continues to move to the bottom dead center (second Figure d).

External work is performed by this movement of the piston 9. The moving direction of the piston 9 is reversed at the bottom dead center and the piston 9 moves to the exhaust process, the exhaust valve 6 opens and the working gas is discharged from the exhaust port 7 (FIG. 2e). At the end of the exhaust stroke, the piston 9 reaches the nearest top dead point of the catalyst holder 3 and returns to the initial state of the cycle. In order to cause the pistons 8 and 9 to move relative to each other as described above, it is necessary to link the movements of the pistons 8 and 9 using a cam mechanism, a link mechanism, or other motion control mechanism. 7 In the internal combustion engine described above, the fuel is used at a low concentration below the flammability limit that does not cause gas phase reactions, and even if a catalyst is used, the heat generated by the surface reaction is used, so there is a risk of explosion when handling the fuel. For example, it can be safely handled at home, and the combustion speed of the fuel can be easily controlled by controlling the contact speed between the fuel mixture and the catalyst, making it possible to effectively reduce heat generation. It can be extracted as power.

In the above-described embodiments, the cylinder of a positive displacement combustion engine is exemplified as the type of combustion chamber of the internal combustion engine.
In addition, the combustion chamber of a high-speed internal combustion engine can also be used.

Furthermore, in the above-described embodiments, the catalyst is kept at a fixed position and the mixture is moved in order to bring the mixture into contact with the catalyst, but the catalyst may be moved within the combustion chamber. [Example] A mixture of hydrogen (4% MOL concentration) and air was used as the reactive substance, and platinum was used as the catalyst.

The pressure P-volume V diagram is as shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is an explanatory longitudinal cross-sectional view showing an internal combustion engine according to an embodiment of the present invention, FIG. 2 is an explanatory view showing the position of the piston in each step of a cycle, and FIG. 3 is an explanatory view of the internal combustion engine shown in FIG. 1. It is a PV diagram in . 2...Cylinder, 3...Catalyst holding part, 5...Intake port, 7...Exhaust port, 8,
9... Piston, 11... Catalyst.

Claims (1)

[Claims] 1. A catalyst is disposed in a combustion chamber, and a reactive air-fuel mixture in which the concentration of reactive substances is below the flammable limit that does not cause a gas phase reaction is passed through the influence area of the catalyst to cause a surface reaction using the catalyst. An internal combustion engine that utilizes a catalytic surface reaction that generates heat through a chemical reaction.