JPS582447A - Exhaust port liner in internal-combustion engine - Google Patents

Abstract

PURPOSE:To enhance heat insulation capability, to enable the working step of removing sand to be omitted and to prevent deformation, crack or the like of the exhaust port liner due to thermal strain by slidably supporting the unsecured side end part of the exhaust port liner, and by forming an annular projection for allowing a heat insulating layer to be sealingly enclosed. CONSTITUTION:The end part 20a of an exhaust port liner 20 on the side of a combustion chamber 10 is partly inserted into and secured to a cylinder head 14, and an insulating layer charged with an insulating material 18 is formed, sorrounding around an exhaust port 16. In the inner peripheral surface of the exhaust port of the cylinder head 14 in the vicinity of the exhaust port outlet side end part 20c of the exhaust port liner 20 which corresponds to the unsecured side end part of the exhaust port liner 20, an annular projection 22 capable of sealingly enclosing the exhaust port outlet side end part 18b of the insulating layer charged with the insulating material 18 and having a width (1) is formed for slidably supporting the exhaust port outlet side part 20c of the exhaust port liner 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust port liner for an internal combustion engine, and in particular,
Suitable for use in automobile internal combustion engines with exhaust gas purification measures! The present invention relates to an improvement in an exhaust port liner for an internal combustion engine, which is made of a tubular material whose one end is fixed to the cylinder head and is installed inside the exhaust boat of the cylinder head to form a heat insulating layer around the exhaust boat.

In internal combustion engines, especially automobile internal combustion engines that are equipped with exhaust gas purification measures, it promotes the reaction of the oxidation reaction exhaust manifold or catalytic converter installed in the exhaust system to obtain good exhaust purification performance. Therefore, it is necessary to guide the exhaust gas in a high temperature state to the oxidation reaction exhaust manifold, catalytic converter, etc. without letting the heat of the exhaust gas passing through the exhaust boat formed in the cylinder head escape to the cylinder head. Conventionally, therefore, exhaust port liners have been used, for example, consisting of a tubular material fixed to the cylinder head at one end and mounted inside the exhaust boat of the cylinder head to form a heat insulating layer around the exhaust boat. . Conventionally, in such an exhaust port liner, one end of the exhaust port liner made of a tubular material, especially the end on the exhaust port outlet side, is opened in order to secure an air layer between it and the cylinder head as a heat insulating layer. In many cases, in such an exhaust port liner with one end open,
After casting, not only does it take time to remove the sand that has filled up between the exhaust port liner and the cylinder head, but if the sand removal is incomplete and sand remains inside the insulation layer, it may damage the internal combustion engine. When pulp overlaps during operation, it may enter the cylinder and cause abnormal wear of the cylinder, etc. or,
Since part of the exhaust gas flows into the heat insulating layer from the open end of the exhaust port liner, part of the heat of the exhaust gas escapes to the cylinder head, resulting in a problem of poor heat insulation performance. This also applies to exhaust port liners in which a heat insulating material is filled in the heat insulating layer after removing sand.

In order to solve the above-mentioned problems, it is possible to fill the insulation layer with insulation material and then seal the insulation layer, but if the exhaust port liner becomes thermally distorted due to the influence of high-temperature exhaust gas, , the exhaust port liner may become thermally deformed or cracked, making it impossible to seal the insulation material, and in extreme cases, leaked insulation material may enter the cylinder, causing abnormal wear of the cylinder, piston, and piston ring, resulting in engine failure. may cause.

Furthermore, when determining the thickness of the heat insulating layer, it has traditionally been determined based on the heat insulating effect and the possibility of removing sand. In consideration of ease of removal, the thickness of the heat insulating layer may be made thicker than necessary, leading to an increase in the size of the cylinder head or a reduction in exhaust gas discharge performance.

The present invention has been made to solve the above-mentioned conventional drawbacks, and is an exhaust port for an internal combustion engine that has high heat insulation performance, eliminates the need for removing sand, and does not cause deformation or cracking due to thermal distortion. The purpose is to provide liners.

The present invention relates to an exhaust port liner for an internal combustion engine, which is made of a tubular material whose one end is fixed to a cylinder head and is installed inside an exhaust boat of a cylinder head to form a heat insulating layer around the exhaust boat. The above object is achieved by forming an annular protrusion in the vicinity of the non-fixed side end of the nuclear exhaust boat liner, which slidably holds the non-fixed side end of the nuclear exhaust boat liner and can be enclosed in the heat insulating layer pipe. It is.

Further, the annular projection is formed on the inner peripheral surface of the exhaust boat of the cylinder 2 bed.

Alternatively, the annular projection is formed on the outer peripheral surface of the exhaust port liner.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The first embodiment of the present invention, as shown in FIG.
The side end 20a and the tip of the pulp stem guide insertion part 20b around the valve stem guide 12 of the exhaust valve are made of a tubular material that is half inserted into the cylinder head 14 and fixed, and a heat insulating material 18 is provided around the exhaust port 16. In order to form a heat-insulating layer filled with air, the exhaust bow of the silicate head 14)1
6 Exhaust port liner of internal combustion engine installed inside 20V
At c, the exhaust port outlet side of the exhaust port liner 20 is placed on the exhaust boat inner circumferential surface of the cylinder head 14 near the exhaust/boat outlet side end 20C, which is the non-fixed end of the exhaust port liner 20. The end portion 20c is slidably supported. An annular protrusion 22 having a width l is formed so as to be able to enclose the exhaust port outlet side end of the heat insulating layer filled with the heat insulating material 1B. In the figure, 24 is a valve seat of an exhaust valve.

The width l of the annular protrusion 220 is set to a width that is possible in manufacturing in order to improve the sealing performance of the heat insulating layer.

According to this first embodiment, the heat insulating layer filled with the heat insulating material 18 is not only enclosed in the combustion chamber side end 20a of the exhaust port liner 20 and the pulp stem guide insertion part 20b, but also on the exhaust boat outlet side. Since the end portion 20 cVc is also enclosed by the annular protrusion 22, it is in a completely sealed state, and exhaust gas does not flow into the heat insulating layer filled with the heat insulating material 18, thereby achieving high heat insulation performance. I can do it. or,
Even if the inside of the heat insulating layer is filled with sand, it will not enter the cylinder and will not cause engine failure. Furthermore, even when the exhaust port liner 20 is thermally expanded and contracted as shown by arrow A in FIG.
Since the exhaust port liner 20 only slides on the annular projection 22, the exhaust port liner 20 will not be thermally deformed or cracked.

A second embodiment of the invention is shown in FIG. In this embodiment, similar to the first embodiment, the tip of the combustion chamber side end 26a and the pulp stem guide insertion portion 26b is connected to the cylinder head 14.
In the exhaust port liner 26 that is fixed to the cylinder head 14 in a state where Vc is halfway inserted, the exhaust port outlet side end 2 which is the non-fixed side end of the exhaust port liner 26
An annular protrusion 26d that slidably supports the exhaust boat liner 6c and is capable of enclosing a heat insulating layer filled with a heat insulating material 18 is formed to protrude from the outer peripheral surface of the exhaust boat liner 26 itself. The other configurations and effects are the same as those of the first embodiment, so their explanation will be omitted.

In this embodiment, there is no need to complicate the shape of the exhaust boat of the cylinder bed, and the cylinder head can be manufactured easily.

In each of the above embodiments, the combustion chamber side end portions 20a, 26a of the exhaust port liner 20.26 and the pulp stem guide insertion portions 20b, 26b have their tips inserted into the cylinder head 14. However, the method of fixing one end of the exhaust port liner 2o, 26 to the cylinder head 14 is not limited to this, and for example, the method shown in FIG. As shown in the enlarged front view of part m in FIG. 2, a projection 14a is provided on the cylinder head 14, and the combustion chamber side end 20a of the exhaust port liner 20.26 is attached to the projection 14a.

Of course, it is also possible to fix one end of the exhaust port liner 20.degree. 26 to the cylinder head 14 by engaging the tip of the valve stem guide 26a or the lower insertion portion of the valve stem guide.

As explained above, according to the present invention, the exhaust gas passing through the exhaust port does not flow into the heat insulating layer.
The exhaust gas purification performance is improved because the heat of the exhaust gas does not escape to the cylinder head and the exhaust gas is guided to the oxidation reaction exhaust manifold or catalytic converter in a high temperature state. In addition, the labor of removing sand can be omitted, which not only reduces costs, but also allows the thickness of the heat insulating layer to be kept to the minimum necessary. Furthermore, thermal deformation, cracking, etc. due to thermal expansion and contraction of the exhaust port liner are eliminated, and the reliability of the internal combustion engine is improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a first embodiment of an exhaust port liner for an internal combustion engine according to the present invention, and FIG.
3 is an enlarged sectional view of the part shown in FIGS. 1 and 2, showing a modification of the method of fixing one end of the exhaust port liner to the cylinder head in each of the embodiments. It is. lO... Combustion chamber, 14... Cylinder head, 16.
...Exhaust port, 18...Insulation material, 20.26...
- Exhaust port liner, 20a, 26a... combustion chamber side end, 20c, 26c... exhaust port outlet side end (non-fixed side end), 22.26d... annular projection. Agent Takaya Theory No. 1 Figure 4 Figure 2 Figure 3 @I4α

Claims (3)

[Claims] (1) An exhaust port liner for an internal combustion engine that is made of a tubular material whose one end is fixed to the cylinder head and is installed inside the exhaust boat of the cylinder head to form a heat insulating layer around the exhaust boat. An exhaust port liner for an internal combustion engine, characterized in that an annular protrusion that slidably supports the non-fixed side end of the exhaust port liner and is capable of enclosing the heat insulating layer is formed near the non-fixed side end of the exhaust port liner. . (2) The exhaust port liner for an internal combustion engine according to claim 1, wherein the annular projection is formed on an inner circumferential surface of an exhaust boat of the cylinder head. (3) The exhaust port liner for an internal combustion engine according to claim 1, wherein the *i protrusion is formed on the outer peripheral surface of the exhaust board liner.