JPS5856355Y2 - 3-valve cylinder head - Google Patents

Description

[Detailed description of the invention] The present invention relates to a three-valve cylinder head, and in particular, with regard to the arrangement of the fuel valve, improvement of the cooling performance of the cylinder head and fuel valve 9
The aim is to reduce weight and improve castability.

In an internal combustion engine, the cylinder head serves as the lid of the cylinder and together with the piston forms the combustion chamber, so it is exposed to high temperature and pressure, so a cooling water passage is provided to cool it, but in the case of a general easel engine, there is a mounting hole for the fuel valve in the center. A fuel valve port is provided, and intake and exhaust valve mounting holes and intake and exhaust ports that communicate with these are formed around the fuel valve port, and the area around these holes is used as a water jacket for cooling. The cylinder head has a complicated structure because it allows water to flow through it, and the lower surface forms the hot water surface, which is the upper surface of the combustion chamber, and must withstand the gas pressure and thermal stress caused by combustion.

In addition, the size of the intake and exhaust valves, which affects the performance of the engine, is determined by the flow rate of air or gas when the valves open, so a two-valve type with one intake and exhaust valve each would result in too high a flow rate. In a diesel engine aimed at small size and high output, taking into account
2 intake valves.

In many cases, a three-valve engine with one exhaust valve is used, and in this case, the structure is simpler and manufacturing costs are lower compared to a four-valve type cylinder head with two intake and exhaust valves each. However, in the three-valve type, the fuel valve can be inserted from outside the locker room, making it easier to maintain the fuel valve and simplifying the structure of the cooling water passage around the fuel valve. It has many advantages such as

However, in the case of a three-valve type, the structure is inevitably more complex than a two-valve type, and especially in engines with a cylinder diameter of 100 mm or less, the smaller the cylinder head, the more difficult it is to cast the cylinder head and the thickness of the water jacket. There are limits to the size of the fuel valve and limits to the miniaturization of the fuel valve, etc., and the flow of cooling water in the water jacket may be affected due to uneven thickness of the hot water surface or excessive thickness between ports or between the ports and the fuel valve. The temperature difference between the intake port and exhaust port and the non-uniformity of the hot water surface temperature will become large, and there is a risk of distortion and cracking. This results in insufficient fuel consumption and increases the temperature, resulting in disadvantages such as a decrease in the durability of the fuel valve.

The present invention aims to solve the above-mentioned drawbacks of the conventional three-valve type cylinder head. installed between the intake valve insertion holes,
3, characterized in that the intake valve is installed through a common intake port that communicates with the two intake valve insertion holes.
The object of the present invention is to provide a valve type cylinder head.

Hereinafter, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a three-valve cylinder head according to an embodiment, and FIGS. 2 and 3 are a sectional view taken along line II and II-■■ in FIG. 1, respectively.

In the figure, a fuel valve 1 indicated by a two-dot chain line is inserted into a fuel valve mounting hole 7 diagonally formed in the upper wall 5 of the cylinder head 3, and its tip 9 is located on the lower surface of the cylinder head 3 and is located above the combustion chamber. It is diagonally drilled in the hot water surface 11 forming a surface, inserted into a bottom hole 13 provided on an extension of the fuel valve mounting hole 7, and perpendicular to the cylinder head 3 for mounting two intake valves. Two intake valve insertion holes 15 and 17 are provided on the left and right sides of the fuel valve 1.

That is, the fuel valve 1 is installed obliquely toward the hot water level 11 from the fuel valve mounting hole 7 provided outside the locker room 19 that accommodates the swinging arm provided at the upper part of the cylinder head 3, and there are two fuel valves. The fuel valve 1 is installed between the intake valve insertion holes 15.17 of the intake valve 1, and the fuel valve 1 is inserted into the intake valve 1 such that its body 21 is exposed in the intake port 27 which communicates in common with the two intake valve seats 23.25. It is attached through the port 27.

On the side opposite to the fuel valve 1 with respect to the intake valve insertion hole 15.17, there is one exhaust valve insertion hole 3 communicating with the exhaust port 29.
1 are perpendicularly bored in the cylinder head 3, and the intake valve insertion holes 15.17 and the exhaust valve insertion holes (L31 are arranged to form each vertex of a triangle).
17, wall body 33,35 covering this, exhaust valve insertion hole 31
and a wall 37 covering it. Intake port 27. Exhaust port I
・29 and the walls 39 and 41 that cover it are a series of water jackets! -43, 45, 47, and a cooling nozzle 57.55 is bored in a bulge 53.55 that protrudes upward from the bottom wall 49. 59 is provided with threaded portions 61 and 63 for screwing a pipe joint at its inlet portion, and its outlet 65
, 67 with the water jacket 47, and with the water jacket 43.45 through guide holes 69 and 71 passing through the bulges 53 and 55.

Next, to explain the operation of the above embodiment, the cylinder head 3 is fixed to the cylinder block by bolts (not shown) inserted into the mounting holes 73, and the cooling water cooled through the fresh water cooler or radiator is Cooling nozzle 57
．． The fuel valve 1 flows into the water jacket 47 from each outlet 65, 67 and is inserted into the fuel valve mounting hole 7.
is cooled and then flows into the water jacket (43.45).

Also, some of the cooling water that enters the cooling nozzles 57 and 59 directly flows through the guide holes 69 and 71 into the cooling water jacket 43 and 45, where it joins with the cooling water that has flowed in from the water jacket 47 described above and is then discharged at the upper part of the combustion chamber. The exhaust gas flows out of the cylinder head 3 while cooling the exhaust valves and exhaust ports 29 fitted in certain bottom walls 49 and 51 and the exhaust valve insertion holes 31.

In addition, the intake air that has passed through the supercharger and been cooled through the air cooler enters the intake port 27 of each engine from the intake manifold.
While cooling the body 21 of the fuel valve 1, the intake valve seats 23 and 25
It flows into the combustion chamber through the space between the intake valve and the intake valve.

Furthermore, the exhaust gas that has passed through the exhaust valve flows into the exhaust manifold through the exhaust port 29.

As described above, in the present invention, the fuel valve is installed from outside the locker room diagonally toward the hot water surface, and the fuel valve is installed between the two intake valve insertion holes, and the fuel valve is installed between the two intake valve insertion holes. It is installed through the common intake port that communicates with the intake valve insertion hole, reducing the distance between the fuel valve and the intake valve and the distance between the intake valves, and separating the high-temperature exhaust valve insertion hole from the low-temperature one. Because the distance between the intake valve insertion hole and the intake valve becomes larger,
The temperature gradient is reduced, so cracks between the valves do not occur, and castability is improved, and since the fuel valve is exposed in the low-temperature intake port, the cooling effect of the fuel valve is significantly increased, improving the durability of the fuel valve. Not only that, but the weight of the cylinder head was also reduced because part of the wall that used to completely cover the fuel valve was no longer needed.

In addition, as mentioned above, as a result of widening the distance between the intake and exhaust valves, the thickness of the water jacket can be increased, which allows the cooling water to flow smoothly, significantly improving the cooling performance. Scale, etc. may accumulate on the surface, causing local overheating.
Due to the stagnation of water flow, gas, air, and water vapor in the water separate and accumulate, preventing local overheating and eliminating the risk of cracking the valve wall.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a three-valve cylinder head according to one embodiment, and FIGS. 2 and 3 are a cross-sectional view taken along line II and II-II in FIG. 1, respectively. 1... Fuel valve, 11... Hot water level, 15.
17... Intake valve insertion port, 19... Locker room, 27... Intake port.

Claims (1)

[Scope of utility model registration request] It consists of a three-valve cylinder head with two intake valves and one exhaust valve, and the fuel valve 1 is installed from outside the locker room 19 diagonally toward the hot water surface 11.
installed between the intake valve insertion holes 15 and 17, and
A three-valve cylinder head characterized in that it is installed through a common intake port 27 that communicates with two intake valve insertion holes 15 and 17.