JPH08319808A - Engine intake/exhaust valve structure and manufacture of cylinder head part - Google Patents

Abstract

PURPOSE: To reduce the temperature of a seat part by forming the intake/ exhaust valve seat part of a cylinder head as a simultaneous casting structure at the time of aluminum alloy casting, and arranging a heat transmission range on an intermediate range formed between the intake/exhaust valve seat part and a cooling water passage by a copper material so as to improve heat transmission property. CONSTITUTION: A seat part cooling structure, an exhaust valve cooling structure, and a casting method for a cylinder head are realized. The seat part cooling structure formed integratedly at the time of casting for the cylinder head, is constituted in such a way that an annular seat part 5 is formed on the work of press punch surface treatment without cut-working heat resistance metal oxide, an annular copper material part 3 approaches the seat part 5, and the copper material part 3 is arranged in a restricting position of a casting mold beforehand. An exhaust valve cooling structure is formed by a valve structure whose weight is reduced by filling aluminum in a valve system shaft center part, as a means for alleviating reduction of the center range temperature of a valve system 1 and seating shock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to performance improvement and manufacturing technology of an internal combustion engine.

[0002]

2. Description of the Related Art It is known that an intake / exhaust valve located in a cylinder head portion which is a part of a combustion chamber comes into contact with a flow of a high temperature combustion gas, so that it has a large heat load and a high temperature.

Therefore, abnormal combustion due to a high temperature hot surface adversely affects engine performance and durability. In particular, the exhaust valve tends to reach a high temperature, and measures have been taken to reduce the temperature of the exhaust valve, such as by providing a sodium sealing valve or a cooling water passage near the valve seat as a means to suppress this temperature, but the exhaust valve temperature is still sufficient. The current situation is that we cannot control it.

Recently, for the purpose of reducing the weight of the engine, the cylinder head portion is mainly made of aluminum alloy rather than cast iron. Therefore, it is general to use a heat resistant alloy for the exhaust valve seat and press fit this. However, in this method, since the seat press-fitting surface and the aluminum alloy main body are not sufficiently adhered and bonded, it is not possible to sufficiently lower the seat temperature. It is an obstacle.

[0005]

Since the exhaust valve exposed to the high temperature combustion gas naturally has a high temperature, it is necessary to move the heat in the support shaft direction and the valve seat direction in order to lower the temperature. A cooling method by encapsulating sodium is used as one means, but it is known that there is little merit in cost.

Although various methods have been devised for cooling by the heat conduction effect through the seat portion, it is absolutely necessary to lower the temperature of the seat portion on the cylinder side in order to enhance the cooling effect. Will be greatly involved.
Therefore, it is difficult to solve this problem with the current seat part press-fitting method.

The present invention provides a cooling method for quickly moving the seat temperature of a high temperature valve to the cylinder head side by making the seat portion on the cylinder side as low as possible, and the seat portion structure and intake / exhaust valve shaft. The purpose of the present invention is to provide a method for cooling a valve center portion in which a portion is filled with a lightweight and highly heat-conductive aluminum material, and a method for constructing a cylinder head portion having a cooling sheet portion.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a cylinder head side seat portion structure, and as a means for more effectively conducting heat from a sheet member, a cylinder head portion casting is performed without using a conventional press-fitting method. At the same time, a ring-shaped valve seat portion is previously arranged on a part of the core, and at the same time as casting, a good joint between the seat portion and the head material is achieved.

By this method, the thickness of the sheet member required by the conventional press-fitting method is reduced, and at the same time, the sheet member is preliminarily subjected to a surface treatment (Alfin, etc.) to improve the adhesion and bonding property with the cylinder base material. The head valve seat structure that improves the heat conduction by improving the heat conduction and promotes the lowering of the seat temperature by both of these actions, and the heat transfer passage made of copper material with good heat conductivity is further formed close to the seat portion. And a valve structure in which the valve shaft is filled with a lightweight and highly heat-conductive aluminum material to improve the cooling effect, and a cylinder head casting method.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in the drawings as follows. FIG. 1 shows an example of a sheet portion according to the conventional press-fitting method. The press-fitting sheet portion requires cutting of the press-fitting contact surface, and a thickness for maintaining the strength necessary for press-fitting is also required, so material cost is reduced.・ Processing costs increase, and the degree of tight bonding on the press-fitting surface is insufficient, so effective heat conduction cannot be expected.

Further, since heat-resistant metals generally have a low thermal conductivity, it is difficult to quickly move a high temperature from a valve to the head portion. Therefore, the exhaust valve temperature is inevitable. Therefore, the durability of the valve seat portion is rapidly deteriorated.

In comparison with this, the valve seat structure of the present invention has a thin structure which retains the necessary strength against the seating impact of the valve, as shown in FIG. The pre-treatment technology that is easy to adapt to the head base material is applied. A method is used in which the ring-shaped seat portion is previously placed at the intake / exhaust valve position of the casting core and cast.

Further, as shown in FIG. 3, by forming a ring-shaped heat conduction area of copper close to the valve seat, the cooling action is further improved.

Since such a ring-shaped sheet portion is thin even with a heat-resistant alloy, it can be easily mass-produced by punching or pressing, and the cost of pretreatment such as Alfin is low, so the processing cost is reduced together with the material cost. Will be done.

In particular, according to the Alfin treatment, the bondability with the base material (aluminum alloy) is remarkably improved as compared with the press-fitting method, and the thinness of the heat-resistant material and the thermal conductivity of the copper material region contribute to
The cooling effect will be dramatically improved.

[0016]

[Operation] Since the temperature of the head seat decreases, the high temperature region of the exhaust valve end area seat performs heat transfer to the head side promptly through the seat surface when seated. The valve operating temperature is necessarily suppressed.

[0017]

[Effect] The exhaust valve temperature becomes the highest among the various parts that make up the engine combustion chamber, and this high temperature region becomes the source of abnormal combustion in the gasoline spark ignition system, improving the compression ratio and increasing lean burn combustion to improve thermal efficiency. However, the problem was solved by the exhaust valve cooling means according to the present invention. Therefore, high output and low fuel consumption of the engine are realized, and at the same time, the production cost is reduced by reducing the number of cutting machining processes.

Also in the diesel engine, as in the gasoline engine, the temperature control technology of the exhaust valve not only improves the durability and reliability but also improves the air supply efficiency and increases the specific output and can contribute to energy saving.

[0019]

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a conventional valve seat portion press-fitting method.

FIG. 2 is an explanatory diagram of the configuration of the present invention.

FIG. 3 is an explanatory view showing a casting example of a valve seat portion in which a ring-shaped copper portion of a cooling medium is previously joined to a heat resistant alloy for a valve seat.

[0020]

[Explanation of symbols]

1 ... Exhaust valve, 2 ... Ring valve seat, 3 ... Copper ring for cooling, 4
... Cooling water channel, 5 ... Valve seat, 6 ... Aluminum material for exhaust valve shaft core.

Claims (4)

[Claims] 1. A cylinder head side joint surface is previously surface-treated with Alfin or the like to increase the thermal conductivity by making the degree of coupling between the seat portion and the aluminum alloy casting head main body portion high, thereby improving the intake and exhaust valve performance. A ring-shaped seat structure for the cylinder head that is characterized by cooling. 2. A method for cooling an exhaust valve according to claim 1, wherein a cooling region made of copper is formed in a ring shape in the vicinity of the exhaust valve seat. 3. An aluminum alloy cylinder head portion characterized in that a ring-shaped seat portion for an intake / exhaust valve is previously positioned inside a casting mold for a cylinder head, and a seat portion and a copper ring portion are simultaneously cast during casting. Manufacturing method. 4. The engine according to claim 1, wherein the exhaust valve shaft is filled with an aluminum material having a high thermal conductivity to cool the valve central region and reduce the weight of the valve. Intake / exhaust valve structure.