JPH0524943U - Plate heater mounting structure in the engine intake passage - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a mounting structure of a plate heater provided on a surface facing a fuel injection in an engine intake passage. By blowing back when the valve overlaps, atomizing even what has grown up to the upstream side of the fuel injection facing surface,
It is intended to improve the promotion of atomization of injected fuel. [Structure] The plate heater 8 provided on the fuel injection facing surface 5a in the intake passage 5 is extended to the upstream side in the intake passage 5 including the fuel injection facing surface 5a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mounting structure of a plate heater provided on a fuel injection facing surface in an engine intake passage.

[0002]

[Prior Art]

 Conventionally, in the intake passage of a fuel injection engine, a plate-shaped heater is provided along the inner wall of the intake passage at the portion where the injected fuel collides, and by heating this heater when the engine starts, It is known to promote atomization of injected fuel, improve engine startability, and reduce generation of HC at low temperatures.

Thus, injecting fuel into the intake passage before the intake port without directly injecting it into the combustion chamber prevents incomplete combustion due to the insufficiently atomized fuel entering the combustion chamber. Therefore, a heater is provided on the fuel injection facing surface in the intake passage to heat the injected fuel to promote atomization of the fuel and to send the completely atomized fuel to the combustion chamber. It is what This is especially effective when the engine is cold when the engine is started.

[0004]

[Problems to be solved by the device]

 However, in such a conventional plate-shaped heater mounting structure that faces only the fuel injection facing surface, the liquid film of fuel generated on the bottom surface of the intake passage near the heater is blown back when the engine valve overlaps. Since the fuel film also extends and grows on the upstream side of the fuel injection facing surface, if the liquid film of fuel also extends and grows on the upstream side of the fuel injection facing surface in this way, the effect of the heater on this growth portion is exerted. In short, there is a problem that the intended purpose cannot be achieved sufficiently.

The present invention has been made in view of such a problem, and the plate heater is extended to the upstream side of the intake passage including the fuel injection facing surface to provide the fuel injection facing surface. It is an object of the present invention to provide a plate heater mounting structure in an engine intake passage, which is capable of atomizing a liquid film that has grown to the upstream side.

[0006]

[Means for Solving the Problems]

 Therefore, the plate heater mounting structure in the engine intake passage of the present invention is the same as the plate heater mounting structure provided on the fuel injection facing surface in the engine intake passage. It is characterized by being extended to the upstream side in the intake passage.

[0007]

[Action]

 In the above-described plate heater mounting structure in the engine intake passage of the present invention, since the plate heater is provided extending to the upstream side including the fuel injection facing surface, the blowback at the time of valve overlap of the engine is performed. As a result, the liquid film of the fuel grown to the upstream side of the fuel injection facing surface is also atomized well.

[0008]

【Example】

 1 to 6 show several examples of a plate heater mounting structure in an engine intake passage according to the present invention, and FIG. 1 shows a first embodiment of the present invention. 2 is a vertical sectional view of the plate heater mounting structure according to the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is a vertical sectional view of the plate heater mounting structure according to the second embodiment of the present invention, and FIG. 3 is a sectional view taken along the line IV-IV of FIG. 3, FIG. 5 is a longitudinal sectional view of a plate heater mounting structure according to a third embodiment of the present invention, and FIG. 6 is a sectional view taken along the line VI-VI of FIG. , In each figure, the same reference numerals indicate almost the same parts.

First, the first embodiment shown in FIGS. 1 and 2 will be described. Reference numeral 1 in the drawings is a cylinder head, and an intake port 3 opening to the combustion chamber 2 is formed in the cylinder head 1. The intake pipe 4 communicating therewith is connected to form an intake passage 5.

The intake port 3 is provided with an intake valve 6 that can be opened and closed, and the intake pipe 4 is provided with a fuel injection nozzle 7 for injecting fuel toward the intake port 3.

The fuel injection nozzle 7 is attached through the upper wall of the intake pipe 4 with the injection port directed toward the intake port 3, that is, obliquely downward, and on the lower surface of the inner wall of the intake passage 5. An elongated plate heater 8 is provided that extends to the upstream side of the intake passage 5 including the position corresponding to the fuel injection facing surface 5a.

The plate heater 8 is attached to the edge portion 1a of the opening to which the intake pipe 4 of the cylinder head 1 is connected, for example, by using a bolt 9 by means of a mounting leg 8a protruding downward from approximately the middle of the lower surface. It is installed.

By connecting the intake pipe 4 to the intake port 3 of the cylinder head 1, the downstream side portion of the plate heater 8 faces the intake passage 5 of the cylinder head 1, and the upstream side portion of the intake pipe 4 is connected. It faces the inside of the intake passage 5, whereby the downstream side portion 8b of the plate heater 8 is located so as to face the fuel injection facing surface 5a in the intake passage 5, and the upstream side portion 8c is It is arranged so as to be extended further upstream from the fuel injection facing surface 5a.

Further, the plate heater 8 is formed in a circular arc shape as shown in FIG. 2 and is fitted along the inner wall of the intake passage 5 so as to be flush with the inner wall. ing.

In FIG. 1, reference numeral 10 denotes a bolt for attaching the intake pipe 4 to the cylinder head 1.

With the above-described configuration, in this embodiment, the liquid film of the injected fuel generated in the vicinity of the plate heater 8 may be sent to the upstream side and grow due to the blowback during the valve overlap of the engine. Even if there is, since the plate heater 8 is extended to the upstream side, the liquid film grown on the upstream side can be atomized well. Therefore, there is an effect that the startability at the time of starting the engine can be improved and the generation of HC at low temperatures can be reduced.

Further, since the plate heater 8 is provided so as to be flush with the wall surface of the intake passage 5, there is an effect that flow of intake air is not hindered.

Next, the second embodiment shown in FIGS. 3 and 4 will be described. In the second embodiment, as compared with the first embodiment, the main portion 8e of the plate heater 8 is thermally insulated. The heater surface 8d is formed of a material, and only the exposed surface to the intake passage 5 is formed. The other structure is the same as that of the first embodiment.

Therefore, in the second embodiment, substantially the same effects and advantages as in the above-described first embodiment are obtained, and since the portion forming the heater is small and the amount of electricity required for heating the heater is small, The effect of reducing battery consumption can be obtained.

Further, the third embodiment shown in FIGS. 5 and 6 will be described. In the third embodiment, a plate heater 8 is provided on the back surface or outer surface of the plate heater 8 between the cylinder head 1 and the intake pipe 4. A gap portion (air gap portion) 11 having substantially the same size as that of the heater 8 is formed, and other configurations are similar to those of the first embodiment.

Therefore, in the third embodiment, substantially the same effects and advantages as those of the first embodiment described above are obtained, and the temperature of the plate heater 8 rises quickly due to the existence of the air gap portion 11, so that it is not possible. The atomized fuel can also be atomized well, which in turn reduces the current consumption.

It goes without saying that the configuration according to the second embodiment can be applied to that of the third embodiment.

[0023]

[Effect of the device]

 As described above in detail, according to the plate heater mounting structure in the engine intake passage of the present invention, in the plate heater mounting structure provided on the fuel injection facing surface in the engine intake passage, the plate heater is opposed to the fuel injection facing surface. Since it is provided to extend to the upstream side in the intake passage including the surface, the liquid film of the injected fuel generated near the plate heater grows in the upstream direction due to blowback at the time of valve overlap of the engine. Even if it occurs, the atomization of the liquid film is promoted by heating and atomizing it well. Therefore, there are advantages that the startability at the time of starting the engine can be further improved and the generation of HC at the time of low engine temperature can be further reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a plate heater mounting structure according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a vertical sectional view of a plate heater mounting structure according to a second embodiment of the present invention.

4 is a cross-sectional view taken along the line IV-IV of FIG.

FIG. 5 is a vertical cross-sectional view of a plate heater mounting structure according to a third embodiment of the present invention.

6 is a cross-sectional view taken along the line VI-VI of FIG.

[Explanation of reference symbols] 1 cylinder head 1a opening edge 2 combustion chamber 3 intake port 4 intake pipe 5 intake passage 5a fuel injection facing surface 6 intake valve 7 fuel injection nozzle 8 plate heater 8a mounting leg 8b downstream portion of plate heater 8c Plate heater upstream side part 8d Heater surface 8e Plate heater main body made of heat insulating material 9,10 Bolt 11 Air gap part

Claims (1)

[Scope of utility model registration request] 1. A mounting structure for a plate heater provided on a fuel injection facing surface in an engine intake passage, wherein the plate heater extends to the upstream side in the intake passage including the fuel injection facing surface. The plate heater mounting structure in the engine intake passage is characterized in that