JPS63215809A - Pipe internal chill exhaust manifold - Google Patents

Abstract

PURPOSE:To attempt reduction of heat capacity and improvement of durability with ensuring cooling ability of a water jacket by forming an inner pipe of an exhaust manifold by steel and an outer pipe by cast iron, and by unifying both of them through an internal chill process applied on the inner pipe with the outer pipe. CONSTITUTION:Both ends of an exhaust manifold 6 are connected to an exhaust port 4 and a turbo charger 7 respectively. And the exhaust manifold 6 is formed in a double pipe constitution of an inner pipe 8 and an outer pipe 9. Also, most of a port branch part 10 as an exhaust gas passage communicating to the exhaust port 4 is formed by the inner pipe 8, and a water jacket 11 between which and the outer pipe cooling water is flown is formed on the outer circumferential side of the inner pipe 8. In this case, the inner pipe 8 is formed by a steel pipe and unified with the outer pipe 9 made up of cast iron by molding. Also, the both ends of the inner pipe 8 are connected to the outer pipe 9 by each of connecting part 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides an A-ta jacket 1 to an outer periphery of an exhaust gas passage wall.
Regarding the double-pipe exhaust manifold structure.

[Conventional technology] In order to improve the durability of the exhaust manifold bolt and the heat resistance of the supercharger, or to reduce the exhaust temperature, the fuel OT (O
ver Temperature) reduction in volume increase, WOT
(Wide Pen Thtoot LIe) It is known that cooling the exhaust manifold is effective in reducing fuel consumption, improving performance such as engine output torque, and suppressing knocking.

As a forced cooling method for exhaust manifold, Utility Model Application No. 61-5
A method using air cooling may also be considered, as in the case of exhaust pipe cooling in Japanese Utility Model Publication No. 7118 and Japanese Utility Model Application Publication No. 61-78213, but in the case of air cooling, the cooling capacity is limited and great effects cannot be expected.

Various methods using water cooling have been proposed as highly efficient cooling methods.

For example, Utility Model Application No. 61-21814, Utility Model Application No. 61-21814,
Publication No. 134513 discloses that the exhaust manifold has a double pipe structure, an A-water jacket is provided around the outer periphery of the exhaust gas passage wall, and cooling water is allowed to flow through the water jacket. . Conventionally, such a double-pipe exhaust manifold has been manufactured by casting.

[Problems to be Solved by the Invention] However, the conventional water-cooled exhaust exhaust system as described above has the following problems.

First, since the exhaust manifold is formed by old casting, there is a problem in that the exhaust manifold has a large amount of wasted material, and the heat capacity of the exhaust manifold, the heat capacity, increases significantly. As the heat capacity increases, engine warm-up performance deteriorates accordingly, leading to deterioration of exhaust emissions. In addition, the increase in the number of train cars goes against the demand for reductions in engine idle time.

In addition, since cooling water is flowed into the exhaust gas passage wall outer circumference, the difference between the internal temperature of the exhaust gas passage and the exhaust gas passage temperature (exhaust gas temperature) becomes considerably large. The passage walls are made of cast iron, and cast iron has a brittleness of 4.
) Is it the above? It is not very resistant to thermal shock and rapid thermal deformation caused by Au degree difference, and there is a problem that υ1 warp or distortion may occur in the manifold, and the exhaust manifold lacks durability and reliability. be.

The present invention has focused on the above-mentioned problems, and aims to reduce heat build-up of the exhaust manifold and improve durability and reliability, while ensuring cooling performance by A-cooling.

[Means for Solving the Problems 1] The pipe-casting exhaust manifold of the present invention, which meets this objective, has a two-wheel structure with an inner pipe and an outer pipe, with the inside of the inner pipe serving as an exhaust gas passage, and the inside of the inner pipe serving as an exhaust gas passage. In this exhaust manifold, the inner pipe is made of steel, the outer pipe is made of cast iron, and the outer pipe is cast around the inner pipe to form the outer pipe. It consists of an exhaust manifold with a double pipe structure in which a pipe and an inner pipe are integrated and have a jacket.

[Function] In such a pipe-casting exhaust manifold, by making the inner pipe made of steel using a steel pipe or steel plate,
The inner pipe can be covered with a thinner wall than when made of cast iron, reducing the heat capacity and weight of the exhaust manifold, and the high-temperature strength of the inner pipe can be increased compared to when using cast iron, making it more resistant to thermal shock, etc. Durability and reliability can be improved. Moreover, since the steel inner tube is integrated with the outer tube by being cast into the cast iron outer tube, it is possible to ensure sufficient mutual bonding strength. Moreover, since the outer tube side is not directly exposed to high-temperature exhaust gas than the inner tube side, the temperature is relatively low, so cast iron can be used to improve the joint strength with the inner tube, reduce costs, etc. Select the material and press No.17.

[Embodiments] Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pipe casting υ1 according to an embodiment of the present invention.
Showing air manifold. In the figure, 1 is the engine,
2 is a cylinder block, 3 is a cylinder block, 4 is an exhaust port, and 5 is an exhaust valve. An exhaust manifold 6 is connected to the exhaust port 4, and a turbocharger 7 is connected to the exhaust manifold 6. 6 has a two-wheel tube structure with an inner tube 8 and an outer tube 9, and the inner tube 8 constitutes most of the port branch portion 10 as an exhaust gas passage communicating with the exhaust port 4. On the outer circumferential side of the inner tube 8, a cooling water socket 11 is constructed to allow cooling water to flow between the inner tube 8 and the outer tube 9. In this embodiment, the inner tube 8 is made of a steel pipe (for example, stainless steel), and is integrated with the cast iron outer tube by a casting. Both ends of the inner tube 8 are
Each is joined to the outer tube 9 side at a joining portion 12.

The cross-sectional shape of the exhaust manifold 6 is, for example, 6 in FIG.
As shown in the example for a cylinder, it is determined appropriately according to the request from the engine. In the @ structure shown in Fig. 2, the left and right banks 13 and 14 have inner pipes 15 and 15 for three cylinders, respectively.
16 are provided, and these are cast into an outer tube 17 made of cast iron.Each inner tube 15, 16 can be formed by welding steel tubes, or as shown in FIG. As shown, the water jacket 18 may be formed by welding the upper and lower parts (pressed steel products).Also, as is clear from FIG. Change it to jqru.

The exhaust manifold 6 shown in FIG. 1 is manufactured as shown in FIG. In FIG. 3, 19 indicates a boat core part, and 20 and 21 indicate an upper mold and a lower mold, respectively, of the core mold. In the example shown in Fig. 3, the inner tube 8 is
1, and the core sand of bow 1 to core part 19
, B, the core sand of the A-tajatsu 1 to the core portion 22 is filled, for example, from the filling hole 23 of the upper die 20, and the gas at that time is drawn out from the hole 24. By filling the core sand and hardening it by vibration or the like in this manner, the boat core 19 and the A-jacket core 22 can be formed simultaneously with the inner tube 8 sandwiched therebetween. In addition, 25 is -F lower mold 20.21
It shows the child cutting line.

FIG. 4 shows a case where the inner tube is made from a steel plate (a pressed steel plate product). For simplicity of explanation, a linear inner tube configuration is shown. As shown in FIG. 4(a), the inner tube 26 is
It is composed of two upper and lower divided bodies 28 and 29 that sandwich the boat core 27, and as shown in FIG. 4 (b), by welding the mating surfaces 30 of the divided bodies 28 and 29, Bow integrated with inner tube 26 (- core 27 can be molded. 3
1 is a projection for positioning. For the water jacket core, the molded body shown in Fig. 4 (b) is
All you have to do is heat it to 0.21 and mold it.

As shown in FIGS. 3 and 4, since the A-ta jacket core is held by the ball core 19 (27) and the inner tube 8 (26), the A-ta jacket core No special core support is required.Therefore, as shown in FIG. 2, a relatively free shape can be selected.

The pipe casting exhaust manifold constructed as described above will be described with reference to the apparatus shown in FIG.

Exhaust gas from the exhaust boat 4 passes through the boat branch portion lO of the exhaust manifold 6, and is cooled by cooling water in the exhaust jacket 11. Since the inner tube 8 forming the majority of the boat branch portion 10 is made of a steel tube, the wall thickness of the umbilical cord can be made thinner than when the entire exhaust manifold is manufactured by casting. In terms of strength, steel has higher high-temperature strength than cast iron, so sufficient strength can be ensured even with thin walls. When the inner tube 8 is thin, the jI[ of the exhaust manifold 6 as a whole is reduced, and the heat capacity is also kept small. In addition, as a result of increasing the high-temperature strength of the inner tube 8, which comes into direct contact with high-temperature exhaust gas, there is a risk of cracking due to thermal shock, etc., or rapid thermal deformation, which was a problem when it was made of cast iron. The possibility of distortion occurring is also eliminated.

In addition, the inner tube 8 is joined to the outer tube 9 by casting 8112.
However, this part, which is the boundary between steel and cast iron, is metallurgically bonded by the heat during casting, so it becomes almost one piece after casting.
The occurrence of defects (pores, etc.) between the branch portions 10 (gas passages) is prevented.

Additionally, spheroidal graphite cast iron or the like is normally used for exhaust manifolds in order to ensure high-temperature strength, but if the carbon content is high, the bond between the steel and cast iron described above may become weak. However, since the outer tube 9 side is kept at a relatively low temperature,
It is possible to use lower grades of cast iron. Therefore, if there is a risk of weakening the bond with steel due to carbon inclusion,
All you have to do is reduce the carbon content of cast iron.

[Effects of the Invention] As explained above, when using the pipe-casting exhaust manifold of the present invention, by using steel for the inner pipe of the exhaust manifold having a two-car pipe structure, good cooling by the A-taper jacket can be achieved. While ensuring performance, the heat capacity of the exhaust manifold,
It is possible to reduce weight and increase high temperature strength. In addition, since steel has high toughness, it is possible to absorb thermal deformation only in the inner tube, suppressing deformation of the flange of the exhaust manifold, and maintaining its normal function. .

In addition, since relatively inexpensive materials such as gray cast iron can be used for the cast iron of the outer pipe, it is possible to both ensure efficient exhaust manifold cooling performance with the A-ta jacket and reduce costs. .

Furthermore, the inner surface of the steel that constitutes and covers the inner tube, such as a steel pipe, is cleaner than the surface of a cast surface in the case of casting, which also has the effect of smoothing the flow of exhaust gas.

Furthermore, by selecting the steel material for the inner tube, it is possible to further improve the cooling efficiency.

In addition, the exhaust manifold 1- up to the 2Φ pipe structure blocks the transmitted exhaust sound and reduces noise, and improves the rigidity of the turbo engine.
7-JJI It is also possible to suppress the vibration of the trachea.

In addition, a strong cold l that hits the foot, [
], it is possible to reduce heat dissipation to the exhaust manifold 1111 side, and also to prevent heat damage to peripheral parts.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a pipe-cast exhaust manifold according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of an example of the shape of a pipe-cast exhaust manifold according to the present invention, and FIG. Fig. 4 (a) is a longitudinal cross-sectional view showing an intermediate manufacturing process of the exhaust manifold shown in Fig. 4; is a perspective view of the assembled state of the inner tube in FIG. 4(a). 1... Engine 3... Cylinder head 4...
・・・・・・・・・Exhaust boat 6・・・・・・・・・・・・
・Exhaust manifold 7・・・・・・・・・Tarho:
f-t nojar 8.15.16.26 Inner pipe 9.17 Outer pipe 10 Board branding section 11.
18...tsut-tashaketsu1-12...
・・・・・・・・・Joint part 19.27・・・Boat core 20.21・・・ Core mold 22・・・・・・・・・1rit -Taji (1 Utsudo core 28.29... split body

Claims (1)

[Claims] (1) In an exhaust manifold configured with a double pipe structure of an inner pipe and an outer pipe, with the inside of the inner pipe serving as an exhaust gas passage and a water jacket formed between the inner pipe and the outer pipe, the inner pipe is made of steel. A pipe-casting exhaust manifold characterized in that the outer pipe is made of cast iron, and the outer pipe and the inner pipe are integrated by casting the outer pipe around the inner pipe.