JPH0542660U - Engine with exhaust port liner - Google Patents

Abstract

(57) [Abstract] [Purpose] A heat insulating space is easily formed at the boundary between the exhaust port liner and the cylinder head. [Structure] A groove 15 is formed on the outer surface of the exhaust port liner 15.
A large number of D, 15D, ... Are provided in a grid pattern. When the exhaust port liner 15 is cast around with an aluminum material in a heated and melted state, the aluminum material cannot penetrate into the recessed grooves 15D because of its large surface tension, and the recessed grooves 15D and the cylinder head 5 are not connected to each other. An air layer 16 as a lattice-shaped heat insulating space is formed at the boundary of the.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine equipped with an exhaust port liner, which is mounted on, for example, an automobile and has an exhaust port liner for preventing a decrease in temperature of exhaust gas.

[0002]

[Prior Art]

 In general, an engine with an exhaust port liner that has a two-layer structure made of a ceramic material and has an air layer formed between these layers to enhance the heat insulation effect is generally used for the engine with an exhaust port liner. It is known from Japanese Utility Model Publication No. Sho 63-1 83451.

Here, the exhaust port liner, after forming an outer cylinder made of a ceramic material, deposits a ceramic solution in the outer cylinder to provide a deposition layer, and the deposition layer is dried, fired, and contracted. The inner cylinder is formed by forming an air layer between the outer cylinder and the inner cylinder to obtain a heat insulating effect.

[0004]

[Problems to be solved by the device]

 By the way, according to the above-mentioned conventional technique, since the inner cylinder is formed inside the outer cylinder after the outer cylinder is formed, the manufacturing process involves a wide variety of processes, which results in the manufacturing process. There is a problem that the workability of is greatly reduced.

Further, since the inner cylinder of the exhaust port liner is formed by thermal contraction of the deposition layer made of the ceramic solution, it is difficult to uniformly form the inner cylinder and the air layer, and the shape is defective. Therefore, there is a problem in that the yield is significantly reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide an engine with an exhaust port liner in which a heat insulating space can be easily formed at the boundary between the exhaust port liner and the cylinder head. Has a purpose.

[0007]

[Means for Solving the Problems]

 The features of the configuration adopted by the present invention to solve the above-mentioned problems are a cylinder, and an intake port and an exhaust port that communicate with the inside of the cylinder by being mounted on the cylinder and molded by aluminum die casting. And a piston that reciprocates in the cylinder to define a combustion chamber between the cylinder head and the cylinder head. Exhaust gas that is opened and closed and an exhaust port provided in the cylinder head that opens and closes the exhaust port with respect to the combustion chamber to discharge exhaust gas from the combustion chamber toward the exhaust port An engine with an exhaust port liner comprising a valve and an exhaust port liner cast inside the cylinder head to form an exhaust port of the cylinder head. , On the outer surface side of the exhaust port liner is provided with a plurality of grooves, in that a configuration which forms an insulating space in the boundary portion between the respective grooves and the cylinder head.

[0008]

[Action]

 With the above configuration, when the exhaust port liner is cast inside the cylinder head, the surface tension of the aluminum material is used to form a heat insulating space at the boundary between each groove and the cylinder head, and When exhaust gas flows into the combustion chamber, the heat insulating space prevents the temperature of the exhaust gas from decreasing.

[0009]

【Example】

 Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4 by taking an engine with an exhaust port liner for an automobile as an example.

In FIG. 1, reference numeral 1 denotes an engine body of an automobile engine. The engine body 1 is a multi-cylinder cylinder 2 (only one cylinder is shown) provided on a crankcase (not shown). A cylinder head 5 mounted on each cylinder 2 and having a pair of intake ports 3 and a pair of exhaust ports 4 communicating with the inside of each cylinder 2 and a reciprocating motion within each cylinder 2 And a piston 7 that defines a combustion chamber 6 in each cylinder 2 between and. The piston 7 derives the combustion pressure generated in the combustion chamber 6 as a rotational output from a crankshaft (not shown) via the connecting rod 8.

A reference numeral 9 is provided on the cylinder head 5 so as to be liftable via a bush 10 and is separated from and seated on a valve seat 11 on the front end side of each intake port 3 so that each intake port 3 is separated from the combustion chamber 6. A pair of intake valves that open and close (only one is shown). Each intake valve 9 opens in the intake stroke of the piston 7, and the fuel flows from each intake port 3 toward the inside of the combustion chamber 6. It is intended to suck in a mixture with intake air.

Here, the air-fuel mixture sucked into the combustion chamber 6 is compressed by the piston 7 (compression stroke), explodes and burns by being ignited by a spark plug (not shown), and the combustion pressure generated at this time is generated. Then, the piston 7 is pushed downward to perform the expansion stroke.

A reference numeral 12 is provided on the cylinder head 5 so as to be liftable via a bush 13 and is separated from and seated on a valve seat 14 on the tip end side of each exhaust port 4, so that each exhaust port 4 is set in the combustion chamber 6. A pair of exhaust valves that open and close (only one is shown) are shown. Each of the exhaust valves 12 opens in the exhaust stroke of the piston 7, and exhaust gas as combustion gas generated in the combustion chamber 6 is released. The gas is discharged from each exhaust port 4 toward an exhaust pipe (not shown). Exhaust gas that has burned in the combustion chamber 6 and has a high temperature of about 400 to 850 ° C. is discharged into each of the exhaust ports 4. And, in the middle of the exhaust pipe, a catalyst device (not shown) made of a three-way catalyst such as platinum or palladium is provided, and when the exhaust gas having a temperature of 350 ° C. or higher flows into the catalyst device, The heat accelerates (activates) the catalytic reaction and removes harmful components in the exhaust gas by oxidation reaction and the like.

Reference numeral 15 denotes an exhaust port liner integrally formed with the cylinder head 5 so as to form each exhaust port 4 in the cylinder head 5. The exhaust port liner 15 is made of a ceramic material such as aluminum titanate. As shown in FIG. 2, it is formed in a substantially V-shaped tubular shape, and one end side thereof forms a pair of port portions 15A, 15A which communicate with the inside of the fuel chamber 6 via each exhaust valve 12 and the like, and The end side is a merging portion 15B that merges the respective port portions 15A. Further, mounting holes 15C, 15C into which the exhaust valves 12 are loosely fitted are formed at the tip ends of the respective port portions 15A. Further, as shown in FIG. 3, a large number of concave grooves 15D, 15D, ... Are formed in a grid pattern on the outer surface side of the exhaust port liner 15, and each concave groove 15D has a width dimension for the reason described later. It is formed so that S and S are about 1 mm and the depth dimension h is about 1 mm.

As shown in FIG. 4, 16 is formed in a lattice shape by casting the exhaust port liner 15 in the cylinder head 5 and covering the upper end side of each concave groove 15 D of the exhaust port liner 15. An air layer as an adiabatic space is shown. The air layer 16 prevents the heat of the exhaust gas from being conducted to the cylinder head 5 when the exhaust gas from the combustion chamber 6 flows into the exhaust port liner 15. To prevent.

Next, a method of casting the above-described exhaust port liner 15 around the cylinder head 5 will be described.

First, the exhaust port liner shown in FIGS. 2 and 3 is formed by sludge casting using a split mold (not shown) composed of a plurality of molds each having a large number of square holes formed on the inner surface side. Mold 15. Then, when the cylinder head 5 is cast by aluminum die casting, the exhaust port liner 15 is positioned in the molding die of the cylinder head 5 together with the bushes 10, 13 and the valve seats 11, 14 and the like, and the molten state is maintained. Made of aluminum material. Here, the aluminum material forming the cylinder head 5 has a surface tension of 520 dyn / cm in a molten state (750 ° C.), which is larger than that of mercury at room temperature (482.1 dyn / cm), and the aluminum titanate. Since it has a low wettability with respect to ceramic materials such as minium, it is difficult for it to enter into a small gap (about 3 mm or less). As a result, when the exhaust port liner 15 is cast around the cylinder head 5, the molten aluminum material slightly infiltrates into the concave grooves 15D and solidifies, as shown in FIG. A lattice-shaped air layer 16 is formed at the boundary between the groove 15D and the cylinder head 5.

Next, the operation of the engine with the exhaust port liner thus formed will be described.

First, a mixture of air and fuel is sucked into the combustion chamber 6 from the intake port 3 through the intake valve 9, the mixture is compressed by the piston 7, and then ignited by an ignition plug to burn (explode). ), The piston 7 is pushed downward by the combustion pressure at this time, and is output as a rotational output from the crankshaft via the connecting rod 8. Then, the combustion gas (exhaust gas) in the combustion chamber 6 is discharged toward the exhaust port liner 15 by opening the exhaust valves 12. Here, when the exhaust gas from the combustion chamber 6 flows through the exhaust port liner 15, the air layer 16 prevents the heat of the exhaust gas from being conducted to the cylinder 5 and keeps the exhaust gas in a high temperature state. While discharging it to the exhaust pipe side.

Thus, in this embodiment, a large number of recessed grooves 15D are provided in a grid pattern on the outer surface side of the exhaust port liner 15, and the exhaust port liner 15 is cast around the cylinder head 5 to form a surface of an aluminum material. Utilizing the fact that the tension is large, an air layer 16 as a lattice-shaped heat insulating space is formed at the boundary between each groove 15D and the cylinder head 5. As a result, the air layer 16 can be easily formed, the temperature drop of the exhaust gas can be effectively prevented, and the number of steps and the number of parts at the time of manufacturing can be reduced to improve the workability at the time of manufacturing. Can be greatly improved.

Further, since the exhaust port liner 15 is formed as a single layer by sludge casting using a split mold, it is possible to reliably prevent the exhaust port liner 15 from being deformed or cracked. In addition, it is possible to prevent the occurrence of defective shapes and significantly improve the yield.

Further, when the exhaust port liner 15 is cast into the cylinder head 5, the aluminum material as the material of the cylinder head 5 slightly invades into the respective recessed grooves 15 D of the exhaust port liner 15. Therefore, the adhesion between the exhaust port liner 15 and the cylinder head 5 can be significantly improved, and the displacement and peeling due to thermal expansion can be prevented, and the reliability and the life can be significantly improved. ..

Although the exhaust port liner 15 is described as being formed in a substantially V shape (a type that branches into two) in the above-described embodiment, the present invention is not limited to this, and for example, a type that does not branch. You may form in other shapes, such as a type branched into three.

In addition, in the above-described embodiment, it has been described that the recessed grooves 15D are provided in a grid pattern on the outer surface side of the exhaust port liner 15. However, instead of this, for example, each recessed groove is independent. It may be formed in the shape of a hole, or as in the modification shown in FIGS. 5 and 6, a long rectangular groove having a width dimension S'and a depth dimension h'of about 1 mm, respectively. 15D ', 15D', ... May be formed on the outer surface side of the exhaust port liner 15 '.

Further, in the above-described embodiment, the width dimension S, S and the depth dimension h of each concave groove 15D of the exhaust port liner 15 are described as being formed to be about 1 mm, respectively, but the width dimension S, S is It is not limited to this as long as it is smaller than about 3 mm. Further, the depth dimension h may be 1 mm or more as long as it is within the range allowed for strength.

Furthermore, although the air layer 16 is taken as an example of the heat insulating space in the above-described embodiment, the heat insulating space is provided by casting the exhaust port liner 15 in the cylinder head 5 in a vacuum space. A vacuum layer may be used, in which case heat conduction can be minimized to further improve heat insulation.

[0027]

[Effect of the device]

 As described above in detail, according to the present invention, since a large number of concave grooves are provided on the outer surface side of the exhaust port liner body, the surface tension of the aluminum material can be reduced by surrounding the exhaust port liner with the cylinder head. By utilizing this, a heat insulating space can be easily formed at the boundary between each groove and the cylinder head, and the man-hours and the number of parts at the time of manufacturing can be reduced to improve workability and the like. In addition, the exhaust port liner can have a single-layer structure, which can prevent a defective shape from occurring and improve the yield. Furthermore, the aluminum material can be slightly infiltrated into each groove to improve the adhesion between the exhaust port liner and the cylinder head, preventing misalignment and peeling during thermal expansion etc. And life can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an essential part of an engine with an exhaust port liner according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a port liner in FIG.

FIG. 3 is an enlarged perspective view showing an arrow A portion in FIG.

FIG. 4 is a vertical cross-sectional view showing an enlarged part B in FIG.

FIG. 5 is an enlarged perspective view of a main part of an exhaust port liner according to a modified example of the present invention.

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

[Explanation of symbols]

 2 Cylinder 3 Intake port 4 Exhaust port 5 Cylinder head 6 Combustion chamber 7 Piston 9 Intake valve 12 Exhaust valve 15,15 'Exhaust port liner 15D, 15D' Recessed groove 16 Air layer (insulation space)

Claims (1)

[Scope of utility model registration request] 1. A cylinder and mounted on the cylinder,
By being molded by aluminum die casting, a cylinder head having an intake port and an exhaust port communicating with the inside of the cylinder, and reciprocating in the cylinder,
A piston that defines a combustion chamber between the cylinder head, an intake valve that is provided in the cylinder head and that opens and closes the intake port with respect to the combustion chamber, and a piston that is provided in the cylinder head, An exhaust valve for discharging exhaust gas from the combustion chamber into the exhaust port by opening and closing the exhaust port with respect to the combustion chamber, and an exhaust port of the cylinder head for forming the exhaust port in the cylinder head. In an engine with an exhaust port liner consisting of a cast exhaust port liner, a large number of concave grooves are provided on the outer surface side of the exhaust port liner, and a heat insulating space is provided at the boundary between each concave groove and the cylinder head. An engine with an exhaust port liner characterized by being configured to form