JP2519219Y2 - Engine parts with manifold exhaust passage - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Field of Industrial Use The present invention relates to an engine part having a manifold type exhaust passage,
In particular, it is composed of a cast component body and a manifold ceramic liner that is cast around the component body to form a manifold exhaust passage, and the ceramic liner branches from the hollow cylindrical liner body and the liner body. The present invention relates to improvement of an engine component having a plurality of cylinders.

(2) Conventional Technology Conventionally, as an engine component of this type, for example, Japanese Patent Laid-Open No. 59
The one disclosed in Japanese Patent Publication No. 111985 is known.

(3) Problems to be Solved by the Invention In the engine component using the ceramic liner, the branch region of the ceramic liner where the adjacent two cylinders branch off during engine operation is a high temperature exhaust gas flowing through the two cylinders. Is easily overheated by. In addition, it is desirable to minimize the radius of the inner surface of the branch area so that the high-temperature exhaust gas in both cylinders can be smoothly guided to the liner body, but this is difficult in terms of molding, and as a result, the inner surface of the branch area will be hot. Exhaust gas tends to stay.

As a result, thermal stress is concentrated in the branch region, but since the conventional engine parts do not employ means for relaxing the concentration of the thermal stress, cracks are likely to occur in the branch region. There's a problem.

Further, when casting the component body, in the branch region of the ceramic liner, the molten metal is cooled by the ceramic liner and the core, so that there is a problem that the hot running property is poor.

It is an object of the present invention to provide the engine component that can solve the above problems.

B. Configuration of the Invention (1) Means for Solving the Problems The present invention is composed of a cast component body and a manifold ceramic liner that is cast around the component body to form a manifold exhaust passage. In the engine component having a manifold type exhaust passage, the ceramic liner has a hollow tubular liner body and a plurality of tubular bodies that branch from the liner body. The region is provided with a penetrating portion that communicates the inside and the outside thereof, and the opening of the penetrating portion on the inner surface side of the ceramic liner is formed to be larger than the opening on the outer surface side of the ceramic liner, and from the penetrating portion to the inside of the ceramic liner. A guide portion that projects and guides the exhaust gas in each cylinder to the liner body is cast and formed integrally with the component body.

(2) Operation With the above-described configuration, the guide portion integrated with the component body serves as a heat transfer path during engine operation, and the heat in the branch area is released to the component body through the heat transfer path. Since the high temperature exhaust gas flowing through the tubular body is smoothly guided to the liner body side by the guide portion, overheating of the branch region is prevented and the concentration of thermal stress is relieved. Further, at the time of casting the component body, the molten metal filled in the penetrating portion to be brought into close contact with the guide portion provides a heat retaining effect, so that the hot running property in the ceramic liner branch region is improved.

In this case, the opening of the through portion on the inner surface side of the ceramic liner is formed larger than the opening on the outer surface side of the liner,
Not only is the anchor effect of the guide portion on the ceramic liner (penetrating portion) improved, but a sufficient amount of molten metal to fill the penetrating portion during casting of the component body can be ensured, and the ceramic liner has a good heat retaining effect. It is possible to further improve the hot running property in the branch region.

(3) Embodiment In FIGS. 1 to 4, an engine cylinder head 1 as an engine component includes a manifold type intake passage, and in the illustrated example, a bifurcated pipe type intake having one inlet 2 and two outlets 3. A passage 4, a manifold exhaust passage, and a bifurcated exhaust passage 7 having two inlets 5 and one outlet 6 in the illustrated example, and an aluminum alloy cylinder head body 8 as a cast component body. The cylinder head main body 8 is cast into a manifold type, which forms an exhaust passage 7, and is a bifurcated tube type ceramic liner 9 in the illustrated example.

2 to 8, the ceramic liner 9 is made of alumina titanate (Al ₂ O ₃ .TiO ₂ ) as a ceramic raw material.
, Whose alumina titanate has a relatively small three-point bending rupture stress σ _B and a relatively low Young's modulus E, and also has a small coefficient of thermal expansion and thermal conductivity, and an excellent thermal shock resistance. It has properties and is optimal as a constituent material for this type of ceramic liner 9.

The ceramic liner 9 has a hollow tubular liner body 10 and a plurality of, in the illustrated example, a pair of first and second tubular bodies 11 ₁ and 11 ₂ branching from the liner body 10. Adjacent first and second cylinders 1
A branch region R of the ceramic liner 9 into which 1 ₁ and 11 ₂ branch, in the illustrated example, a penetration that communicates the inside and the outside from the base end a of both cylinders 11 ₁ and 11 ₂ to both facing portions b of the peripheral wall of the liner body 10. The long hole 12 as a part is formed so as to extend in series. Reference numeral 13 is a through hole for inserting the valve guide 14.

As clearly shown in FIG. 8, in the long hole 12, the width c _{1 of the} opening existing on the inner surface side of the ceramic liner 9 (for example, 9 to 11).
mm) is the width c of the opening on the outside of the ceramic liner 9
_It is set to be larger than ₂ (for example, 3 to 5 mm), so that the slot 12 has a dovetail cross section. The inner surfaces d of both ends of the long hole 12 in the longitudinal direction are formed into an arc surface.

Further, as clearly shown in FIG. 9, glass g is filled in the voids f such as fine holes and cracks existing in the inner wall e of the elongated hole 12. In the figure, h indicates alumina titanate particles.

As the glass g, at least one selected from silicate glass, borate glass and phosphate glass is used.

When filling the glass g into the void f, the dispersion liquid of glass particles is applied to a ceramic molded body made of alumina titanate to impregnate the void f by capillary action,
Then, the glass g is melted in the sintering process of the ceramic molded body. Blending alumina titanate as a blending component in the dispersion is effective for strengthening, and when blending alumina titanate, the dispersion may become a slurry.

An example of manufacturing conditions of the ceramic liner 9 is as follows.

Diameter of alumina titanate particles 0.1-10μm; molding method
Slip casting: Glass particles used in dispersion silicate glass particles, diameter 1 μm or less, compounding amount 20% by weight, dispersion medium; Sintering temperature after coating the dispersion
1500 ℃, sintering time 5 hours.

When filling the glass g into the voids f, the above-mentioned coating impregnation treatment is performed after sintering, and then heat treatment is performed, or primary sintering treatment at 300 to 1400 ° C. for 0.5 hours, which corresponds to the ceramic liner 9. It is also possible to adopt a method in which the above-mentioned coating impregnation treatment is performed on the ceramic pre-sintered body that has been subjected to the above, and then the secondary sintering treatment is performed on the ceramic pre-sintered body.

In this case, the heat treatment condition at the time of applying the coating after sintering is 1100 to 1400 ° C. in the air for 1 to 5 hours, and the secondary sintering treatment condition is the sintering treatment condition, that is, ,
Sintering condition of alumina titanate (1500 to 1600 ℃, 3
~ 10 hours).

An example of casting conditions for the cylinder head body 8 using the ceramic liner 9 will be described below.

Ceramic liner 9 preheat temperature 150 ℃, aluminum alloy (JIS AC2B) melt temperature 750 ℃, melt injection pressure 0.25k
g / cm ² , application of low pressure casting method.

The ceramic liner 9 is cast around the cylinder head body 8 by the casting. At this time, as shown in FIGS. 3 and 4, the guide hole forming cavity formed in the elongated hole 12 and the core (not shown) existing in the ceramic liner 9 is filled with the molten metal so that the elongated hole is formed. A guide portion 15 protruding from the inside of the ceramic liner 9 is integrally formed with the cylinder head body 8. The guide portion 15 has a V-shaped slope k
And its slope k lies on an extension of the inner surface of both cylinders 11 ₁ , 11 ₂ . In this case, since the molten metal filled in the long holes 12 provides a heat retaining effect, the hot running property in the branch region R of the ceramic liner 9 is improved, and thus the adhesion between the cylinder head body 8 and the ceramic liner 9 is improved. Can be made.

With the above structure, the guide portion 15 provided on the cylinder head body 8 serves as a heat transfer path during engine operation, and the heat in the branch region R is released to the cylinder head body 8 through the heat transfer path. The high temperature exhaust gas flowing through the two cylinders 11 ₁ and 11 ₂ is smoothly guided to the liner body 10 by the guide portion 15 as shown by the arrow in FIG. Concentration is eased. This prevents the occurrence of cracks in the branch region R.

Further, since the portion m of the guide portion 15 facing the elongated hole 12 is formed to have a cross section, the anchor effect of the guide portion 15 is obtained, and the adhesion between the cylinder head body 8 and the ceramic liner 9 is improved. .

Further, during the engine operation, due to the difference in the thermal expansion coefficient and the thermal contraction coefficient between the aluminum alloy and the ceramics, slippage occurs between the elongated hole 12 and the guide portion 15, but as described above, the elongated hole 12 When the space f existing in the inner wall e is filled with the glass g and the inner wall e is reinforced, the inner wall e can be prevented from being damaged by the reinforcing action.

Furthermore, since the inner surfaces d at both ends of the elongated hole 12 are formed into arcuate surfaces, the concentration of thermal stress on both ends can be relaxed.

When using a ceramic liner not having the long hole 12 as described above, on the inner surface side of the long hole 12 corresponding portion in the branch wall,
Due to the small radius of the arc, a chip is generated due to the compressive stress accompanying the solidification shrinkage of the molten metal. However, when the elongated hole 12 is provided as described above, there is also an advantage that there is no part where such a chip occurs. .

FIG. 10 shows an example in which the inner surfaces d of both ends of the elongated hole 12 in the longitudinal direction are formed into a circular arc surface with a truncated circular shape in order to reduce the concentration of thermal stress.

The engine component of the present invention also includes an exhaust manifold. In this case, the exhaust manifold comprises a cast exhaust manifold body and a manifold ceramic liner that is cast around the body.

C. Effect of the Invention According to the present invention, in the operating state of the engine, the guide part integrated with the component body can be used for the heat transfer path, through which the heat in the branch region can be dissipated to the component body side. In addition, since the high temperature exhaust gas flowing through each cylinder can be smoothly guided to the liner main body side by the guide portion, overheating of the branch region is prevented and the concentration of thermal stress is relaxed. It is possible to effectively avoid the occurrence of cracks. Further, at the time of casting the component body, the molten metal filled in the penetrating portion to be brought into close contact with the guide portion exerts a heat retaining effect, and thus the hot running performance in the ceramic liner branching region can be enhanced accordingly.

Further, in particular, since the opening of the penetration portion on the inner surface side of the ceramic liner is formed larger than the opening on the outer surface side of the liner, not only the anchor effect of the guide portion on the ceramic liner (penetration portion) becomes good, but also the casting of the component body The sufficient amount of molten metal to be filled in the through-hole at the time of heating can be ensured, and the good heat-retaining action of the molten metal further enhances the hot running property in the ceramic liner branching region, which results in close contact between the component body and the ceramic liner. It can greatly contribute to the improvement of sex.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention, FIG. 1 is a vertical sectional front view of a cylinder head, and corresponds to a sectional view taken along the line II in FIG. 2, and FIG. II-II arrow view, FIG. 3 is a sectional view taken along the line III-III in FIG. 1, FIG. 4 is an enlarged view of the portion indicated by arrow IV in FIG. 3, FIG. 5 is a perspective view of the ceramic liner, and FIG. A plan view of the ceramic liner, FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6, and FIG. 8 is a sectional view of FIG.
FIG. VIII-VIII sectional view, FIG. 9 is an enlarged view of an arrow IX in FIG. 8, and FIG. 10 is a plan view showing another example of the ceramic liner. a ... base end, b ... opposing part, c ₁ , c ₂ ... width, d ... inner surface, e ... inner wall, f ... gap, g ... glass, R ... branching region, 1 ... Cylinder head (engine part), 7 ...
… Bifurcated tube exhaust passage (manifolded exhaust passage), 8 …… Cylinder head body (cast component body), 9 …… Bifurcated tube ceramic liner (manifold ceramic liner), 10 ……
Liner body, 11 ₁ , 11 ₂ ...... First and second cylinders, 12 ...... long hole (penetration part), 15 ...... guide part

Claims (5)

(57) [Scope of utility model registration request] 1. A cast component body, and a manifold ceramic liner that is cast around the component body to form a manifold exhaust passage. The ceramic liner is a hollow tubular liner body and the liner body. In an engine component having a manifold type exhaust passage having a plurality of cylinders branched from, a branch portion of the ceramic liner where two adjacent cylinders branch is provided with a penetrating portion that communicates the inside and outside thereof, An opening of the penetrating portion on the inner surface side of the ceramic liner is formed so as to be larger than an opening on the outer surface side of the ceramic liner, and the exhaust gas in each cylinder is projected to the inside of the ceramic liner from the penetrating portion to the liner body side. An engine component having a manifold type exhaust passage, characterized in that a guiding portion for guiding is cast and formed integrally with the component body. 2. An engine component provided with a manifold type exhaust passage according to claim 1, wherein glass is filled in a void existing in the inner wall of the penetrating portion. 3. The divergent portion according to claim 1 or 2, wherein the penetrating portion is a long hole formed so as to extend in series from the base ends of the two adjacent tubular bodies to the opposing portions of the peripheral wall of the liner body. Engine parts with a tubular exhaust passage. 4. An engine component having a manifold type exhaust passage according to claim 1, wherein the inner surfaces of both longitudinal ends of the elongated hole are arcuate surfaces. 5. An engine component having a manifold type exhaust passage according to claim 1, wherein the inner surfaces of both end portions in the longitudinal direction of the elongated hole are formed into a circular arc surface having a truncated circular shape.