JPS58217778A - Internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable to start a diesel engine with ease in a cold district in winter, by lowering the combustion temperature of fuel by applying an oxidizing catalyst over the surface of the heating part of a glow plug. CONSTITUTION:In case that a glow plug 4 is made of a ceramic material, the surface of the glow plug is impregnated with an oxidizing catalyst. In case that the glow plug 4 is made of a metal, on the other hand, a catalyst solution obtained by esterifying propylene glycol in a mixed solution of chromic anhydride, cobalt acetate propylene glycol and admixing chloroplatinic acid and palladium chloride to the mixed solution is applied over the surface of a heated metal, and then it is subjected to oxidation by applying heat treatment after the esterification has proceeded further. The glow plug thus manufactured can promote oxidation with insufficient oxygenation and lower the combustion temperature of fuel of a diesel engine. Therefore, it is enabled to facilitate starting of the engine in a cold district in winter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a glow plug (rod-shaped heating element) installed in an internal combustion engine.

The startability of internal combustion engines deteriorates in winter and in cold regions, and in diesel engines in particular, the temperature of the combustion chamber is low, so the temperature of the compressed air does not rise and the injected fuel often does not ignite. Glow plugs (rod-shaped heating elements) made of aluminum or ceramic are used and are heated electrically.However, in cold regions with low temperatures, it is not easy to start the ignition even with electric heating plugs, and these plugs are Battery power was sometimes consumed during repeated energization operations.

The present invention aims to provide an internal combustion engine that can be started by ignition quickly with as little electric power as possible, and relates to an internal combustion engine characterized in that the engine is equipped with a glow plug having an oxidation catalyst attached to the heat generating part. It is something.

Generally, when an oxidation catalyst is used, the normal combustion temperature is 500 to 4
Today, it is common knowledge that the temperature decreases by 00°C, and unlike general flame combustion, the oxidation reaction proceeds even in an atmosphere without sufficient oxygen (minimum flame combustion oxygen amount). The present invention completely improves the startability of an internal combustion engine by applying this oxidation catalyst to a glow plug, and even when the engine is not energized,
If the temperature of the plug is heated by combustion gas, the heat causes an oxidation reaction and as a result, further heat is generated, further improving combustibility.The oxidation catalyst used in the present invention is particularly limited. chromate, cobalt chromate, magnesium chromate, zinc chromate, etc.
Ordinary oxidation catalysts are used, but among them, the present inventors have previously proposed a catalyst for treating exhaust gas from internal combustion engines (Japanese Patent Publication No. 58264/1983), which contains chromite containing cobalt and nickel as base metals and a small amount of precious metals. Mixtures of platinum and palladium are particularly preferred.

The glow plug used in the present invention is one in which a metal wire electric heating element is covered with a metal pipe, or one in which an electric heating element made of a porous ceramic sintered body is used without a covering. However, in any case, the surface of the glow plug is impregnated with or adhered to an oxidation catalyst with a thickness of 1 to 10 μm.0 In the case of a ceramic sintered plug, powder of alumina, silica, titania, etc. However, since it is porous and can be impregnated with a catalyst solvent solution relatively easily, it is made by mixing metal powder and metal oxide powder and sintering it, but if the heating element is a metal pipe. If the metal surface is coated, it is difficult to coat (adhere, adhere) the catalyst on the metal surface. 21629), the coating progresses relatively smoothly.

That is, 20 parts by weight of an aqueous solution of chromic acid anhydride and the same amount of an aqueous cobalt acetate solution are mixed in advance, and this volume and the same volume of a 50% propylene glycol aqueous solution are mixed to proceed with sufficient esterification, and then a small amount of A catalyst solution obtained by mixing chloroplatinic acid and an aqueous palladium chloride solution is used.

This solution is applied onto a metal surface heated to 200°C or higher to further advance the esterification reaction, forming a blackish brown catalyst film, which is completed by heat treatment (400°C or higher). In this case, it is better to pre-treat the metal surface to enlarge the surface area by acid treatment, shredding or blasting. Figure 1 shows a partially cutaway view of the engine near the glow plug. In the figure, 1 is a swirl chamber, 2 is a combustion chamber mouthpiece, 5 is a fuel injection valve, 4
is the glow plug, 5 is the communication hole, 6 is the cylinder head, 7
8 is a piston, 8 is a cylinder liner, and an oxidation catalyst is adhered to the entire heat generating part 4a of the globe jig 4.

FIG. 2 shows the combustion characteristics of the glow plug A of the present invention provided with the chromic acid conolt oxidation catalyst manufactured in this manner and the conventional glow plug B to which no oxidation catalyst is applied. The combustion characteristics were as follows: 10 minutes after inserting a heated plug into an air chamber containing 5000 ppm toluene vapor;
This shows the relationship between the combustion rate of toluene and the temperature of the plug, and shows that the plug A of the present invention has the same efficiency as the conventional plug B at a temperature approximately 500°C lower, and the startability of the internal combustion engine is improved. It can be seen that it has been greatly improved.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway view schematically showing a glow plug portion of an internal combustion engine of the present invention, and FIG. 2 is a graph comparing the combustion characteristics of the glow plug of the present invention and a conventional glow plug.

Claims (1)

[Claims] An internal combustion engine characterized by being equipped with a glow plug to which an oxidation catalyst is attached to the heat generating part.