JPH0734198Y2 - Exhaust device for cylinder head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an exhaust device for a cylinder head, which is characterized by the structure and arrangement of an exhaust port liner of an internal combustion engine and a cooling water passage in the periphery thereof.

[Conventional technology]

When a cylinder head of an internal combustion engine is manufactured with a light alloy casting containing aluminum as a main component, cooling, casting, processing,
There are various advantages such as weight and aesthetics, but heat resistance,
Corrosion resistance and other aspects are inferior to those made of cast iron.To compensate for this, a port liner made of a heat resistant material such as ceramic is cast into the exhaust port where high temperature exhaust passes, and the exhaust gas is exhausted. It has been considered to prevent direct contact with the light alloy. (As an example, Japanese Examined Patent Publication Sho 62-321
(See Japanese Patent Publication No. 55) In particular, when the exhaust turbocharger is directly attached to the cylinder head to use the energy of the exhaust gas of the internal combustion engine as efficiently as possible, the temperature of the exhaust gas flowing through the exhaust port is kept high. Since it must be, it is extremely effective to provide a ceramic port liner,
Not only does the port liner withstand high temperatures, but its thermal conductivity is much smaller than that of light alloys, which prevents the temperature of the exhaust gas flowing through the exhaust port from decreasing.
Further, the amount of heat received from the exhaust gas of the cylinder head, that is, the amount of load heat that must be removed by cooling with cooling water is reduced, and thermal strain is also reduced, which is also advantageous in terms of strength.

[Problems to be solved by the device]

When installing two sets of turbochargers directly attached to the cylinder head in a multi-cylinder engine, for example, an in-line 6-cylinder engine,
It is necessary to collect the exhaust ports of the 3rd cylinder and the 4th to 6th cylinders in the cylinder head. However, in the case of a multi-cylinder internal combustion engine in which the exhaust manifold is formed in the cylinder head, the exhaust manifold is If you try to cast a ceramic liner like this, the ceramic liner will become large and complicated, and as a result,
Not only is it difficult to mold and fire the liner, but ceramic is a hard and relatively brittle material, and the light expansion coefficient of the light alloy that is the material of the cylinder head is different, so the ceramic liner is cast around. During the casting process, cracks may occur on the ceramic liner or the head side due to thermal shock during or after pouring. Even if it does not crack during the casting process, thermal stress remains between the large ceramic liner itself and the light alloy cylinder head, which may cause cracking during use. When using a ceramic liner, there are problems that the yield of the product is poor and the strength cannot be secured. The present invention aims to solve this problem.

[Means for Solving the Problems]

An exhaust device for a cylinder head according to the present invention includes a collective exhaust port that is formed inside a cylinder head of a multi-cylinder internal combustion engine to join exhaust gases of a plurality of cylinders, and is directly attached to the cylinder head so as to communicate with the collective exhaust port. A turbocharger, a ceramic exhaust port liner that is fixed as a lining of the collective exhaust port by a cast case during casting of the cylinder head, and divides the collective exhaust port into a plurality of parts; A cooling water passage provided along the joint is provided near the joint between the exhaust port liners.

[Action]

Since the present invention is configured as described above, the exhaust gas of the internal combustion engine, which is discharged at high temperature in order to enhance the efficiency of the direct-attached turbocharger, is merged into multiple cylinders by the collective exhaust port formed inside the cylinder head. Supply to the turbocharger. At this time, a port liner made of ceramic is lined on the inner surface of the collective exhaust port, and the heat of the exhaust is not absorbed much by the cylinder head because the thermal conductivity of the ceramic is small, and the temperature of the exhaust hardly decreases. Is sent to the turbocharger, and supercharges efficiently. Further, since the heat of the exhaust gas absorbed by the cylinder head is reduced, the load heat amount to be removed from the cylinder head by the cooling water is reduced, the cooling device can be downsized, and the thermal efficiency of the engine is improved. Further, since the ceramic port liner is a group of small ones that divide the collective exhaust port into a plurality of parts, thermal strain is less likely to occur during casting or during operation, and each port liner or cylinder head Prevents cracks from entering. The joint between the port liners is provided with a cooling water passage along the joint, so that it is possible to prevent the joint from being heated to cause thermal strain and damage. The cooling water passage constitutes a part of the cooling water passage that flows through the inside of the cylinder head, and serves to transfer the cooling water.

〔Example〕

FIG. 1 is a view of a cylinder head 1 according to an embodiment of the present invention seen from below, showing four cylinders which are a part of in-line six cylinders. The combustion chambers 2, 3 and 4 of each cylinder are respectively provided with two exhaust valves 5 and 5 and their outlet passages.
6 and 6 are branch passages that merge for each cylinder and have the number of cylinders 7, 8, 9
Further, they merge at a point 10 to form a collective exhaust port (or an exhaust manifold) 11 which collects exhaust for three cylinders and opens at a side surface 12 of the cylinder head 1. In this example, two sets of such collective exhaust ports 11 are provided, but they are formed inside the cylinder head 1 by using a core during casting.

When the casting is performed, the ceramic port liners 13, 14, 15 divided into three small parts are cast in the collective exhaust port 11. The dividing method is radial as in the case of a ring slice, and division along the axial direction of the passage should be avoided because it reduces the strength of the port liner.

Since a seam (or a gap) 16 is formed between the divided port liners, a narrow strip portion of the light alloy is directly exposed to the hot exhaust gas at this joint portion, and the heat of the exhaust gas is emitted from the strip portion to the cylinder head 1. Therefore, there is a possibility that only the vicinity of the joint will be heated strongly and damage due to thermal strain will occur. In order to avoid this, a cooling water passage 17 is provided near the joint 16 in the vertical direction along the joint.

As shown in FIG. 2, cooling water chambers 18 and 19 are provided below and above the collective exhaust port 11 of the cylinder head 1, and the cooling water chamber 18 below is provided with the cooling water of the cylinder block further below. Cooling water that has flowed upward through the sleeve is supplied, and the cooling water in the upper cooling water chamber 19 merges with the other cylinders and then circulates toward the radiator via the thermostat valve. In this way, the cooling water passage 17 along the joint 16 serves to send the cooling water from the lower cooling water chamber 18 to the upper cooling water chamber 19. However, another ascending water channel may be provided in parallel with the cooling water channel 17. 20 is a turbocharger directly attached to the side surface 12, and 21 is another turbocharger on the side of the collective exhaust port.

In the case of the illustrated embodiment, half of the inline 6-cylinder engine is 1,2,3
The exhaust gas of the No. cylinder is guided to the collective exhaust port 11 and supplied to the turbocharger 20. Since the collective exhaust port 11 is lined with three cast ceramic port liners 13, 14 and 15, even if the exhaust temperature is raised to suit the turbocharger 20, the thermal conductivity of the ceramic liner is high. Is low, the amount of heat flowing to the light alloy cylinder head 1 is small, the amount of cooling water to be circulated is small, and there is no concern that the light alloy is heated strongly and melted or cracked. Further, since the port liner is divided into three small parts like 13, 14 and 15, one port liner is small, and even if these are lined up when the cylinder head 1 is cast, they are cracked by thermal shock. Don't worry. Since a cooling water passage 17 is provided vertically in the vicinity of the seam 16 of the port liner, the exhaust heat leaking from the seam is absorbed by the cooling water rising in the passage 17, and only the seam 16 is heated strongly. It does not cause thermal strain.

[Effect of device]

Since the present invention has the above-described function, since the exhaust port is lined by the ceramic liner, the light alloy cylinder head can also pass high-temperature exhaust gas, which increases the efficiency of the turbocharger. It may reduce the cooling load of the engine. Moreover, since the port liner is divided into small parts, there is no risk of cracks in the liner or cylinder head during casting or during use due to the difference in thermal expansion coefficient between the ceramic and the light alloy. Further, since the passage of the cooling water is provided along the seam of the divided liner, the seam is not heated and is not damaged. Other small port liners are easy to manufacture and have a high yield.

[Brief description of drawings]

FIG. 1 is a bottom view showing a cylinder head partly cut away according to the present invention, and FIG. 2 is a longitudinal sectional view showing a state where the cylinder head and the turbocharger are directly attached. 1 …… Cylinder head, 2,3,4 …… Combustion chamber, 5 …… Exhaust valve, 7,8,9 …… Branch passage, 11 …… Common exhaust port, 13,1
4,15 …… Port liner, 16 …… Seam (gap), 17 ……
Cooling water passage, 18,19 ... Cooling water chamber, 20, 21 ... Turbocharger.

Claims (1)

[Scope of utility model registration request] 1. A collective exhaust port formed inside a cylinder head of a multi-cylinder internal combustion engine for joining exhaust gases of a plurality of cylinders, and a turbocharger directly attached to the cylinder head so as to communicate with the collective exhaust port. , A ceramic exhaust port liner that is fixed as a lining of the collective exhaust port by a cast mold during casting of the cylinder head and divides the collective exhaust port into a plurality of parts, and the plurality of exhaust port liners. An exhaust device for a cylinder head, comprising: a cooling water passage provided along the joint near the joint.