JPS6090958A - Structure of heat insulated engine - Google Patents

Abstract

PURPOSE:To improve the heat insulating property of the engine simply and inexpensively by a method wherein a liner, consisting of ceramics contacting with a combustion chamber, is supported to a cylinder head or the like while interposing an air layer and a heat resistant metal tube is arranged at the inside of an exhaust path while interposing the air layer. CONSTITUTION:An oil chamber 30 is provided at the wall part of a cylinder block 26 and a cylinder liner 2, consisting of ceramics, is inserted into the inner peripheral surface of the cylinder block. A cylindrical secion 39 is provided on the lower half of the cylinder head 21 and the cup-shape head liner 4, consisting of ceramics, is engaged with the peripheral wall of the cylindrical section through one pair of rings 23 at the upper and lower part of the peripheral wall. A piston 38 is engaged slidably with the continuous cylindrical surface formed by respective liners 2, 4. Further, a cup-shape crown liner 1, consisting of ceramics, is connected to the upper end of the piston main body 37 so as to form the air layer 6. On the other hand, the exhaust path 34 is formed by inner and outer tubes 11, 15, consisting of the heat resistant metal, and the air layer 42 is formed between both tubes 11, 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adiabatic engine using ceramic materials.

Ceramic materials have excellent heat resistance, but they are expensive, difficult to use for poetic products such as castings, and have problems such as cracking after long-term use. In this case, the heat insulation effect can be effectively exhibited. However, even if the combustion chamber has an insulated structure, the temperature in the exhaust passage drops rapidly after the exhaust gas blows down, so it is necessary to insulate the passage leading to the exhaust turbo supercharger, etc., which utilizes the heat energy of the exhaust gas. Needed. However, using ceramic materials for such exhaust passages
Due to its manufacturing, it has a considerable hardening property, and its passage wall area is large, so it has the drawback of increasing cost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to manufacture a 4'F
- It is an object of the present invention to provide a structure of an adiabatic engine capable of achieving a sufficient heat insulating effect.

For this reason, the configuration of the present invention is such that at least the cylinder head and the piston support a ceramic liner in contact with the combustion chamber with an air layer interposed therein, and an air layer is interposed inside the exhaust passage to support a heat-resistant liner made of ceramic such as stainless steel. It is equipped with metal tubes.

The present invention will be explained based on examples. As shown in FIG. ff11, an oil chamber 30 is provided in the wall of the cylinder block 26, and a cylinder liner 2 made of ceramics is fitted on the inner peripheral surface. And cylinder block 2
6 through the gasket 25 on the upper end surface of the cylinder head 2.
1 are coupled by known means. The upper half of the cylinder head 21 made of metal such as aluminum is provided with an air chamber 22° 33, and the lower half is provided with a cylindrical portion 39. Gaskets 1 and 8 are provided on the upper end wall of the cylinder head 21, and a peripheral wall is provided with gaskets 1 and 8. A cup-shaped headliner 4 made of ceramic is fitted and supported through a pair of upper and lower rings 23, respectively.

The cylindrical portion of the headliner 4 and the cylindrical portion of the cylinder liner f2 form a continuous cylindrical portion, into which the piston 38 is slidably fitted. The piston 38 is made of metal such as aluminum, and a cup-shaped crown liner 1 made of ceramic is attached to the upper end of the piston body 37 that supports the piston pin 29 to form an air layer 6.
7 and knots 1-28. thus,
Cylinder liner 2, headliner 4 and piston 38
A combustion chamber 40 surrounded by a crown liner 1 is formed. An air layer 7 is provided between the helad liner 4 and the cylinder head 21 in the upper half of the combustion chamber 40, which is most exposed to the temperature.

An exhaust boat 41 is formed in the headliner 4. In particular, the exhaust passage 34 connected to the exhaust bow 1-41 is integrally formed inside the air chamber 33 by casting.

That is, the exhaust passage 34 is composed of a metal inner tube 11 and a metal outer tube 15 made of a heat-resistant metal such as stainless steel, which are overlapped and connected to each other at both ends, with an air layer 42 between them. It is formed. A ceramic layer 20 is coated on the inner peripheral surface of the metal inner tube 11 in advance.

The exhaust valve 3 for opening and closing the exhaust boat 41 is also preferably molded from ceramics, the stem of which traverses the exhaust passage 34 and is operatively supported in a guide 3G of ceramics supported on the cylinder head 21. The guide n36 is fitted and supported by a reinforcing fully bent sleeve 35, and an air layer 9 is provided between this metal sleeve 35 and the cylinder head 21.

At the part where the stem of the exhaust valve 3 crosses, the metal inner tube 11 and the metal outer tube 15 that form the exhaust passage 34 are overlapped with each other, and the guide tube 36 is supported so that the end thereof protrudes into the inside of the exhaust passage 34. A hole is provided.

Although not shown, the exhaust bow 1-41 is attached to the headliner 4.
An intake boat similar to that shown in FIG.
Guided and supported.

The exhaust manifold 12 connected to the exhaust passage 34 also includes a metal inner tube 11a and a metal outer tube 15a made of stainless steel or the like, each of which has an air layer or an air chamber containing a ceramic fiber therein. are overlapped with each other to form a flange, and the metal inner tube i1a is cast into the main body of the cast screw.

Contact M pipe 32 and exhaust nozzle 1 of exhaust turbo supercharger 31
4 is similarly configured.

In the case of a diesel engine, combustion gas rises to about 1200°C at about 3/4 load. However, when the exhaust valve 3 opens and the pressure decreases, the temperature in the exhaust passage 34 suddenly increases to 7.
The temperature drops to nearly 00℃.

Under these conditions, the inside of the cylinder is exposed to hot gas, and the temperature of the outer wall of the combustion chamber is high, exceeding the durability temperature of normal metals.
Exceeds 00℃.

In response to such conditions, in the present invention, the piston 38 forming the combustion chamber has a crown life of 1, a cylinder liner 2,
Since the intake valve, exhaust valve 3, and headliner 4 are each made of a liner such as partially stabilized zirconia or silicon silicide, they can sufficiently withstand the temperature of combustion gases. However, although ceramics have excellent heat resistance, they have better thermal conductivity than metals, so the heat of combustion is ¥40 to the screw I/N body 37, cylinder block 26, and cylinder head 21 that support the liner made of ceramics. is transmitted. , crown liner 1 and piston body 37
By providing an air layer 6 between the headliner 4 and the cylinder head 21, and an air layer 7 between the headliner 4 and the cylinder head 21, it is possible to block heat from dissipating to the outside.

In addition, regarding the cylinder block 26, the screws 38
The majority of the combustion stroke occurs between crown liner 1 and headliner 4.
Although it is not provided in the illustrated embodiment, it is preferable to provide it at a portion of the piston 38 that reaches the bottom dead center.

In addition, since an air layer 9 is provided between the cylinder head 21 and the metal sleeve 35 that supports the suum of the intake and exhaust valves 3 made of ceramics, heat from the intake and exhaust valves 3 to the outside is removed. Dissipation can be suppressed.

When the exhaust valve 3 is opened after m-burning culm is completed, the combustion gas in the combustion chamber 40 is sent from the exhaust port 41 to the exhaust turbo supercharger 31 via the exhaust passage 34 and the exhaust manifold 12.

Since an air layer is formed in the passage from the exhaust port 41 to the exhaust nozzle 14 of the exhaust turbo supercharger 31 with double inner and outer metal pipes, the heat insulating effect of this air layer allows exhaust heat to be transferred to the outside. Dissipation can be suppressed.

In particular, in the exhaust passage 34 inside the cylinder head 21, the heat insulation effect can be further enhanced by coating the inner peripheral surface of the metal inner tube 11 with ceramics such as partially stable zirconia having a low thermal conductivity. In addition, in the exhaust manifold 12, inner and outer metal pipes 11a,
If ceramic fiber is filled between the spaces 15a, the heat insulation effect can be further improved and exhaust noise can be suppressed.

As described above, the present invention includes a cylinder liner 2, a headliner 4, and a crown liner 1 made of ceramics on the wall surrounding the combustion chamber 40, and has an air layer between the piston 38 and the cylinder head 21, respectively. By providing 6 and 7, it is possible to provide heat resistance against combustion gas and to block heat transfer to the outside. Furthermore, since the structure is simple, it can be provided at low cost.

In addition, for the exhaust passage from the combustion chamber 40 to the exhaust turbocharging vA31 that utilizes the thermal energy of exhaust gas, metal pipes such as stainless steel are arranged twice inside and outside to form an air layer between them. So what is the shape of the passage?
! Even if it is rough, it can be press-molded during bending, and if it is cast into the cylinder head, it is easy to manufacture, and the cost can be reduced compared to the case where ceramics are used.

In short, this invention uses a ceramic wall and an air layer in the combustion chamber where the combustion gas temperature is highest, and a metal wall such as sfoonless in the exhaust passage where the combustion gas humidity decreases.
The heavy wall and the air layer formed inside the wall provide a heat insulating effect.This makes it possible to provide an engine with excellent heat insulating effect at a low price. Since it can be sent to a supercharger, it can be used to increase engine output and improve thermal efficiency.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of the structure of an adiabatic engine according to the present invention. 1: Crown liner 2 Rainbow liner 3: Exhaust valve 4: Spatula l; Liner 6, 7.9.42: Air layer 1
1: Metal inner tube 15: Metal outer tube 21 Niji cylinder head 26: Cylinder block 31: Exhaust turbo supercharger
34: Exhaust passage 38: Piston 40; Combustion chamber Patent applicant: Isuzu Motors Co., Ltd. Patent attorney Toshio Yamamoto

Claims (1)

[Claims] A liner made of ceramics that is in contact with the combustion chamber is supported at least in the cylinder head and screws with an air layer interposed between them, and a heat-resistant metal pipe such as stainless steel is installed inside the exhaust passage with an air layer interposed between them. An adiabatic engine characterized by: