JPS5937635Y2 - Electric intake heater for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric intake heater equipped with a ribbon-shaped heating wire installed in an intake passage of an internal combustion engine.

BACKGROUND ART In some internal combustion engines for vehicles and the like, an electric or combustion type heater is interposed in the intake passage to heat the air in the intake passage before starting in order to improve startability in cold weather.

The structure of a conventional general electric intake heater for an internal combustion engine is shown in FIGS. 1A and 1B (disclosed on page 252 of "Automotive Diesel Engine", published by Sankaido, April 30, 1971).

The frame body 1 is attached to a gathering part of an intake manifold (not shown), and has a ribbon-shaped heating wire 2 bent in a serpentine shape.
is disposed with substantially the entire surface exposed to the opening surface of the frame 1, that is, the intake passage, and its both ends are fixedly attached to a pair of bolt ends 1.4 passing through both side walls of the case.

The bolt terminals 3 and 4 are connected to the battery via a heater switch (not shown), and when the switch is turned on and the heating wire 2 is energized to generate electricity, the air in the intake passage comes into contact with the outer surface of the heating wire 2. At startup, the air is heated and supplied to each cylinder via each branch of the intake manifold.

In such an electric intake heater with a conventional structure, if an attempt is made to increase the heat radiation area by widening the width of the ribbon-shaped heating wire 20 shown in FIG. 2, the current flowing through the heating wire 2 increases and the power consumption of the battery is accelerated. The increase in the heat dissipation area and therefore the improvement in the intake air heating efficiency has been substantially restricted.

The present invention was devised in view of these conventional drawbacks, and the ribbon-shaped heating wire is shaped to increase the heat dissipation area without increasing the current flowing through the heating wire and therefore the power consumption of the battery, thereby significantly improving intake air heating efficiency. The present invention provides an electric intake heater for an internal combustion engine.

In other words, although the proof by analysis is omitted, in the case of a ribbon-shaped heating wire with a constant thickness, the current flowing through the heating wire is constant, and therefore the resistance value of the heating wire is constant, whereas the conventional ribbon-shaped heating wire Thus, when the area of the cross section perpendicular to the current direction is constant, the outer surface area of the heating wire becomes the minimum.

Therefore, in the present invention, the outer surface area, that is, the heat dissipation area is increased by changing the cross-sectional area of the ribbon-shaped heating wire perpendicular to the current direction with respect to the current direction, that is, the longitudinal direction of the heating wire.

Embodiments of the present invention will be described below based on the drawings.

In the present invention, as shown in FIG. 3, a ribbon-shaped heating wire 11 serving as a heating element is made wider than the conventional wire and is formed by punching out a large number of holes 11a.

The hole 11a can be easily punched out by punching or the like.

Then, the ribbon-shaped heating wire 11 having this shape is placed in a frame similar to that shown in FIG.

If such a ribbon-shaped heating wire 11 is used, the cross-sectional area of the heating wire 11 changes greatly with respect to the current direction due to the formation of the holes 11a. The outer surface area, that is, the heat dissipation area increases significantly,
This significantly improves intake air heating efficiency with the same power consumption.

In addition, as a method of increasing the surface area while keeping the resistance value of the heating wire constant, it is possible to increase the width by thinning the plate thickness, but in the case of heaters for internal combustion engines with severe heat load conditions, thermal expansion However, with the present invention, there is no need to change the plate thickness, so this problem does not occur.

In order to increase the outer surface area of the heating wire 11 as much as possible, it is preferable to make a large number of small-diameter holes 11a and to arrange them so as to increase the rate of change in the cross-sectional area perpendicular to the current direction.

Further, the hole is not limited to a circular hole, but may have a polygonal shape.

Further, as shown in FIG. 4, if only the bent portion 21a of the heating wire 210 held by the frame wall is formed to have the same width as the conventional one, the same frame as the conventional one can be used.

As explained above, the present invention has the extremely excellent feature of increasing the heat radiation area of the ribbon-shaped heating wire as a heating element and increasing the intake air heating efficiency without increasing the power consumption of the battery. It has an extremely simple configuration and can be implemented at low cost.

[Brief explanation of the drawing]

Fig. 1A is a partial sectional view showing the structure of a conventional general electric intake heater, Fig. 1B is a view taken along the line X-X in Fig.
The figure is a perspective view showing a part of the ribbon-shaped heating wire used in the above heater, FIG. 3 is a perspective view showing a part of the ribbon-shaped heating wire used in the electric intake heater according to the present invention, FIG. 4 is a perspective view showing a modified form of the ribbon-shaped heating wire. 11.21... Ribbon heating wire, 11a... Hole.

Claims (1)

[Scope of utility model registration request] In an electric intake heater equipped with a ribbon-shaped heating wire that is installed in the intake passage of an internal combustion engine and heats the air in the intake passage at least before starting the engine, the ribbon-shaped heating wire is bent in a meandering shape and the width direction is It is arranged in the intake passage parallel to the flow direction of the intake air, and a large number of holes are punched out in the thickness direction of the ribbon-shaped heating wire so that the hole is perpendicular to the direction of the current flowing through the heating wire. An electric intake heater for an internal combustion engine, characterized by having a shape in which the surface area increases relative to the cross-sectional area.