JPS6033320Y2 - Internal combustion engine intake air heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake air heating device in which a heating element is housed in a cylindrical container and arranged at a joint between a carburetor body and an intake manifold.

There is an intake air heating device in which a heating element such as a positive temperature coefficient heater is housed in a container consisting of a metal inner cylinder and a resin outer cylinder, and the air-fuel mixture is circulated through the container from a carburetor to an intake manifold. .

Since the inner cylinder is made of a metal with good thermal conductivity, the heat from the heater can be efficiently transferred to the mixer that passes through the inner cylinder.

Additionally, the outer cylinder is made of a heat-insulating resin to prevent heat from escaping from the heater.

Problems with such a structure are cracks caused by thermal stress in the outer resin container and cracks in the heater when subjected to engine vibration.

That is, since the thermal expansion of the outer resin is significantly larger than that of the inner metal, thermal stress is generated due to the temperature difference.

If this thermal stress concentrates on weak points in the resin container, there is a high possibility that cracks will occur.

Furthermore, since the heater is made of a brittle material such as ceramic, cracks may occur due to engine vibration.

Therefore, an object of the present invention is to provide a structure that suppresses the thermal stress of a resin container as an outer cylinder and has a vibration-proofing function.

To achieve this purpose, the outer cylinder is attached via an elastic material such as rubber.

The following will be explained with reference to the drawings. In FIG. 1, 10 is a carburetor and 12 is an intake manifold.

Heat insulator 14, upper and lower gaskets 16.1
The structure is such that the carburetor 10 and the intake manifold 10 are connected with each other across the carburetor 8.

The heat insulator 14 has openings 141 and 142 that communicate with the primary throttle valve 20 and secondary throttle valve 22 of the carburetor 10, respectively (FIG. 2).

Although the opening 141 is larger than the opening 142, it is not a perfect circle in order to reduce the size of the device.
It's missing in some parts.

A heating device 24 is disposed in a large diameter opening 141 of the insulator 14 below the primary throttle valve 20 .

This heating device 24 includes a metal inner cylinder 26 and a resin outer cylinder 2.
8, and a heater 30 using a positive temperature coefficient (PTC) heating element is arranged in an annular space formed by the inner cylinder 26 and the outer cylinder 28 with a cushioning material made of a graphite wire layer 32 inside.

The inner cylinder 26 is formed by bending the upper and lower ends 261 and 262 to form the outer cylinder 2.
It has a structure that is assembled by engaging the upper and lower ends of 8.

The heater 30 generates heat by receiving electricity from the outside, and is provided with an external electrode for this purpose, but is not shown for simplicity of explanation.

The outer cylinder 28 made of resin has a flange portion 281 on its outer periphery, and this flange portion 281 rests on the upper end surface of the intake manifold 10 via the gasket 18.

In addition, the shoulder portion 1 is provided in the opening 141 in the insulator 14.
42 is formed, and a ring-shaped elastic member 34 such as rubber is interposed between the flange portion 281 and the lower end flange portion 101 of the carburetor main body and the upper end flange portion 12 of the intake manifold.
1 through a bolt (not shown).

As a result, the structure is such that the heating device 24 can be attached.

As shown in an enlarged view in FIG. 3, the flange portion 28 of the outer cylinder 28
The elastic material 34 between the disk portion 341 and the annular protrusion 342 is disposed between the disk portion 341 and the insulator shoulder portion 142.
1 fills the gap above the flange 281, and the annular protrusion 342 fills the gap on the sides of the flange 281.

Note that a small space S is left to provide space for the rubber to expand.

The flange portion has a tapered outer surface 282 for ease of assembly.
The rubber material 34 also forms a complementary tapered inner surface 343.

At the time of engine cold start, the heater 30 is energized and the intake air of the air-fuel mixture passing through the inner cylinder 26 is heated.

This gap outer cylinder 28 has a large thermal expansion probably because it is made of plastic.

Since the heat insulator 14 that restrains the outer cylinder 28 is missing at the part 23, if there is no cushion layer made of the rubber material 34 as in the present invention, stress due to thermal expansion will concentrate on this part 23, causing the outer cylinder to 28 may be destroyed.

However, in the present invention, the rubber material 34 is
The rubber material 341 absorbs the axial thermal expansion of the outer cylinder 28, and the radial thermal expansion is absorbed by the rubber material 342.

At this time, the space S serves as an escape for deformation of the rubber due to thermal expansion.

Therefore, thermal destruction of the outer cylinder 28 does not occur.

The rubber material 34 also functions as a vibration damper and protects the heater 30 made of mechanically fragile ceramic.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the intake air heating device of the present invention, and Figure 2 is a cross-sectional view of the intake air heating device of the present invention.
A view along the line ■-■ in the figure, Figure 3 is a partially enlarged view of Figure 1. 10... Carburizer, 12... Intake manifold, 26... Inner cylinder, 28... Outer cylinder,
30... Heating element, 34... Elastic material, 2
81...Flange part.

Claims (1)

[Scope of utility model registration request] An intake air heating device for an internal combustion engine, in which a positive temperature coefficient heating element is arranged between a metal inner cylinder and a resin outer cylinder, and the outer flange of the resin outer cylinder is sandwiched between an intake manifold and a carburetor body. An intake air heating device for an internal combustion engine, characterized in that an elastic material for absorbing thermal stress of a resin outer cylinder is provided at the flange portion.