JPS63981Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the startability of an internal combustion engine starting aid device which includes a seeded glow plug provided in the subchamber of a subchamber type combustion chamber.

Combustion chamber in internal combustion engines, especially diesel engines with a pre-combustion chamber (pre-chamber in pre-combustion engines)
Generally, a glow plug is inserted into the engine to improve the ignitability of the air-fuel mixture, that is, the starting performance.

The heating element facing into the combustion chamber of such a glow plug is generally a seeded type in which a thin electric heating coil is housed in a sheath. As shown in the figure, the airflow inside the combustion chamber is caused by the heating element H of the glow plug.
When this occurs, a large dead space D without airflow is generated downstream of the heating element H, and a turbulent flow T forming a fine vortex is generated. This impairs combustion performance and is a factor that increases the generation of unburned components such as HC and CO.

The present invention was devised in view of the shortcomings of the conventional glow plug type starting aid device, and by changing the cross-sectional shape perpendicular to the axis of at least the sheath portion of the seeded glow plug that faces into the combustion chamber, it is possible to avoid impairing ignition and starting performance. An object of the present invention is to provide a starting assist device that suppresses turbulence caused by collision of airflow generated in a combustion chamber with a heating element, and significantly improves combustibility.

The present invention will be described in detail below based on embodiments shown in the drawings.

Fig. 2 shows a glow plug 1 constituting the present invention, and the cross-sectional shape perpendicular to the central axis of the sheath 3, which is connected to the main body 2 and houses an electric heating coil (not shown) as a heating element, is flat as shown in Fig. 2B. The shape should be an ellipse.

FIG. 3 shows an embodiment in which the glow plug 1 is attached to a swirl chamber 4 of a swirl chamber type combustion chamber.

That is, FIG. 3 shows a case where the central axis of the glow plug 1 is disposed at right angles to the central axis of the cylinder, and the plane including the long axis of the oval shape and the central axis of the sheath 3 of the glow plug 1 is It is arranged so as to be parallel to the airflow generated within the swirl chamber 4.

In this way, the airflow (intake airflow, mixed airflow, combustion airflow) in the swirl chamber 4 flows along a flat curved surface along the long axis of the oval cross section of the glow plug sheath 3. Moreover, compared to a sheath with a circular cross-section, a sheath with an oval cross-section having the same outer surface area and the same calorific value can have a smaller width perpendicular to the airflow direction, resulting in a dead space downstream of the sheath 3 as shown in Figure 4. Since D is also small and the generation of fine vortex-like turbulence is suppressed, a good swirling airflow close to laminar flow is formed, so combustibility is greatly improved and the generation of HC, CO, etc. is also suppressed.

Although the above embodiments have only been applied to a swirl chamber type combustion chamber, it is of course applicable to a pre-combustion chamber type combustion chamber and a direct injection type combustion chamber.
In addition, the mounting angle of the glow plug may be inclined to the cylinder center axis, and the point is that the plane containing the long axis of the glow plug sheath formed in an elliptical cross section is parallel to the airflow generated in the combustion chamber. Any configuration is sufficient as long as it is arranged in

As explained above, in the present invention, the sheath portion of the seeded glow plug facing the combustion chamber is formed into an elliptical cross section perpendicular to the axis, and the plane including the long axis and central axis of the ellipse is parallel to the airflow generated within the combustion chamber. By arranging the glow plug in this way, the airflow flows smoothly along the flat curved surface of the glow plug, further improving combustion performance and suppressing the generation of harmful components such as HC and CO.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the state of airflow in the combustion chamber when it passes through the sheath in a conventional glow plug, Figure 2A
Figure B shows a glow plug constituting the present invention, Figure B is a sectional view taken along line X-X' in Figure A, and Figures 3 and 4 show a structure in which the glow plug shown in Figure 2 is attached to a swirl chamber type combustion chamber. FIG. 3 shows a cross-sectional view of the glow plug in which the central axis of the glow plug is arranged perpendicular to the central axis of the cylinder. FIG. 4 is a diagram showing the state of the airflow in the combustion chamber passing through the sheath of the glow plug in the apparatus of the above embodiment. 1... glow plug, 3... sheath, 4... vortex chamber.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In an internal combustion engine starting auxiliary device comprising a seeded glow plug in which an electric heating coil as a heating element is housed in a sheath, adjacent to a combustion chamber, at least the glow plug faces at least the combustion chamber. The sheath portion is formed so that the cross section perpendicular to the axis has an elliptical shape, and a plane including the long axis and central axis of the ellipse is approximately parallel to the airflow generated within the combustion chamber. A starting assist device for an internal combustion engine characterized by having a glow plug installed. (2) The starting assist device for an internal combustion engine according to claim 1, wherein the glow plug is installed with its central axis parallel to the central axis of the engine cylinder. (3) The starting assist device for an internal combustion engine according to claim 1, wherein the glow plug is installed with its central axis perpendicular to the central axis of the engine cylinder. (4) The combustion chamber in which the glow plug is installed is a swirl chamber;
The starting assist device for an internal combustion engine according to any one of claims 1 to 3, which is a preheating combustion chamber or a combustion chamber of a direct injection engine.