JPH08100702A - Diesel engine - Google Patents

Abstract

PURPOSE: To prevent generation of a streamline of an intake air flow staying or a streamline of an intake air flow returning to a main line by smoothing the streamline of the intake air flow from an intake port into a cylinder liner. CONSTITUTION: In a diesel engine wherein an intake valve seat 4 and a discharge valve seat 14 project outward from the outer periphery of a cylinder liner 1, a lack part 5a is provided on the outlet side of an intake port 5 along the circular shape on the lower part of the cylinder liner 1. Moreover, a sub nozzle port 7 for injecting fuel atomized flow toward an intake valve vertically moving recessed part and an exhaust valve vertically moving recessed part is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-speed and large-sized diesel engine in which the intake port and the injection port of the fuel injection valve are of the two-valve type with one intake valve and one exhaust valve. Regarding

[0002]

2. Description of the Related Art Conventional low-speed large-sized cylinders have diameters of 300-
In a two-valve diesel engine of about 400 mm,
Since the diameter of the valve seat is increased in order to secure the intake amount and the outer circumference of the valve seat projects more outward than the outer circumference of the cylinder liner, the valve vertical movement recess is provided. Then, the outer diameter of the intake port 5 was formed in a shape along the outer periphery of the valve vertical movement concave portion 3. However, in this case, the flow of intake air from the intake port is blocked by the valve vertical movement recessed portion, and an effective intake passage area that matches the size of the valve diameter cannot be obtained. The flow of intake air that collides with the moving recessed portion impedes the flow of intake air that does not collide with the vertically moving recessed portion of the valve, thus reducing the amount of intake air.

In addition, with the increase in output of diesel engines,
It is necessary to increase the injection amount, and for that reason, it is necessary to increase the total injection port area of the fuel valve. The only way to increase the total nozzle area is to increase the number of nozzles or increase the area of each nozzle. However, there is a limit to the increase in the number of nozzles due to the overlap of fuel spray from each nozzle. Also, even if the area of each injection port is increased, there is no problem when the injection pressure is high and the load is high, but when the injection pressure is low and the load is low, the spray characteristics are large and the combustion performance deteriorates because of the large injection port area. It does.

[0004]

SUMMARY OF THE INVENTION The present invention aims to increase the intake amount by optimizing the shape of the intake port, and the increase of the intake amount reduces fuel consumption, exhaust color and heat load. To improve the diesel engine performance.
Further, the valve vertical movement concave portion of the cylinder liner is used so that the fuel spray injected from the auxiliary injection port does not collide with the wall surface of the cylinder liner or the top surface of the piston. As a result, it is possible to obtain a sufficient distance for the fuel spray flow,
Good combustion is obtained.

[0005]

The problems to be solved by the present invention are as described above. Next, the means for solving the problems will be described. In Claim 1, the outer periphery of the valve seat 4 of the intake valve 2 projects outside the outer periphery of the cylinder liner 1 of the internal combustion engine, and the valve that allows the intake valve 2 to move up and down at the upper end of the cylinder liner 1. The valve seat 4 of the intake valve 2 in the configuration provided with the vertically movable recess 3
The outlet side of the intake port 5 communicating with the valve vertical movement recess 3
The valve vertical movement recess 3 of the cylinder liner 1 without
The shape is along the outer circumference of the lower circular arc.

According to a second aspect of the present invention, in the internal combustion engine having the auxiliary injection port 7 in addition to the main injection port 6 as the injection port of the fuel valve, the auxiliary injection port 7 has a smaller injection port diameter than the main injection port 6. The injection port 7 is larger than the injection port angle of the main injection port 6, and the sub injection port 7 is arranged on the center line of the valve vertical movement recess 3 of the cylinder liner 1.

[0007]

Next, the operation will be described. According to the first aspect of the present invention, since a part of the flow of the inflowing air from the intake port 5 can be configured not to collide with the intake valve vertical movement recessed portion 3, the apparent cross-sectional area of the port is reduced. By smoothly aligning the flow lines of the intake flow, the flow line d of the intake flow that stagnates and the flow line g of the intake flow that tries to return to the main line are eliminated, and the intake air amount is increased. As a result, the amount of inflowing air can be increased, fuel consumption and heat load can be reduced, and deterioration of exhaust color can be prevented.

According to the second aspect, since the spray reaching distance can be sufficiently obtained, good combustion can be obtained.

[0009]

EXAMPLES Next, examples will be described. 1 is a plan view showing a cylinder liner 1 and a valve seat 4 of the present invention, and FIG. 2 is a valve seat 4, a cylinder liner 1 and an intake valve 2 of the present invention.
3 is a partial side sectional view of a portion of FIG. 3, FIG. 3 is a view showing a relational position between the intake valve seat 4 and the intake port 5 of the present invention, FIG. 4 is an overhead view showing a flow line of the intake flow of the present invention, and FIG. Of the intake valve seat 4 and the intake port 5 of FIG.
FIG. 6 is a bird's-eye view showing a streamline of a conventional intake flow, FIG. 7 is a drawing showing a comparison of the intake flow rate between the shape of the intake port 5 of the present invention and the shape of the conventional intake port 5, and FIG. 8 is a main injection port. 6 is a side view showing the fuel spray flow of the invention in which 6 and the sub injection port 7 are provided, FIG. 9 is a plan view of the fuel spray flow of the main injection port 6 and the sub injection port 7, and FIG. 10 is a positional relationship between the sub injection port 7 and the main injection port 6. 1 is a side sectional view showing FIG.
FIG. 1 is a drawing showing the relationship between output and exhaust color of the present invention and a conventional structure.

The configuration of the present invention will be described with reference to FIGS. 1, 2 and 3. The diesel engine of the present invention has a low speed, a large piston stroke, and a large diameter of the cylinder liner 1. The diameter of the cylinder liner 1 is, for example, 300 to 40.
It is 0 mm. The valve is a two-valve type with one intake valve 2 and one exhaust valve 12. Since a certain distance is required between the intake valve 2 and the exhaust valve 12 and a certain amount of intake air is required, the outer diameter of the valve also becomes large, and as shown in FIG. Exhaust valve seat 1
The outer diameter of 4 projects from the outer diameter of the cylinder liner 1. An intake port 5 is bored inside the cylinder head H toward the intake valve seat 4, and an exhaust port 15 is bored inside the cylinder head H toward the exhaust valve seat 14 in the same manner.

In a low-speed large-sized diesel engine, when the intake valve seat 4 projects from the outer diameter of the cylinder liner 1, the intake valve vertical movement concave portion 3 and the exhaust valve vertical movement concave portion are formed in the outer peripheral portion of the cylinder liner 1. 13 is provided, and the intake valve 2 and the exhaust valve 12 are provided at this portion.
Is configured so that it can move up and down. In order to prevent a part of the flow line of the intake flow from the intake port from colliding with the intake valve vertical movement recessed portion 3 of the cylinder liner 1, the present invention has a shape on the outlet side of the intake port 5, that is, on the combustion chamber side. The cylinder liner 1 has a shape that follows the circular shape at the bottom. Further, in order that the flow of the intake port 5 can smoothly flow into the cylinder liner 1, the port shape is straight and raised along the outlet shape of the intake port 5. The shape of the exhaust port 15 is as it is along the exhaust valve vertical movement recess 13.

Although the intake port 5 and the exhaust port 15 are bored toward the intake valve vertical movement recessed portion 3 and the exhaust valve vertical movement recessed portion 13, the intake valve vertical movement is conventional as a matter of course. The intake port 5 was opened toward the entire circumference of the intake valve seat 4 including the recess 3. This conventional configuration is shown in FIG. That is, the end of the intake port 5 toward the intake valve seat 4 had a circular cross section. On the other hand, in the present invention, the end surface of the portion where the intake port 5 faces the intake valve seat 4 is
Along the extension of the lower circular portion of the cylinder liner 1, only a half-moon shaped portion is provided with a portion projecting inward, and the shape of the end portion of the intake port 5 is the missing portion of the moon of the sixteenth night. 5a is provided.

With this structure, as shown in FIG. 6, when the end portion of the intake port 5 facing the intake valve seat 4 is formed into a circular shape as in the conventional shape, it occurs in the streamline of the intake flow. It was possible to eliminate the trouble. That is, conventionally, as shown in FIG. 6, a streamline d of the intake flow that flows from the intake port 5 to the intake valve vertical movement concave portion 3 and stays there is generated, and the intake valve vertical movement concave portion 3 is generated.
The flow line g of the intake air flow that is bent at the portion of the line to return to the main line is generated, and the flow line g of the intake air flow collides with the flow line e of the intake air flow that flows straight to form a stagnant portion of the intake air. However, these were overlapped with each other and the intake amount was reduced.

In the present invention, since the lacking portion 5a is formed, the flow line d of the intake flow that stagnates and the flow line g of the intake flow that tries to return to the main line do not occur, and the intake flow that flows straight Since there is only the streamline e, the flow of intake air is smooth, and the shape of the end of the intake port 5 is the missing portion 5a.
It was possible to increase the intake flow rate, despite the fact that the cross-sectional area was reduced only in the area. The state of increase in the intake air amount due to the provision of the missing portion 5a is shown in FIG. 7 as a graph of the relationship between the intake valve lift and the intake air flow rate.

Next, referring to FIGS. 8 to 11, in the cylinder liner 1 provided with the intake valve vertical movement concave portion 3 and the exhaust valve vertical movement concave portion 13, the injection port body 10 of the fuel injection valve is provided.
Next, a configuration in which two types of nozzles, the auxiliary nozzle 7 and the main nozzle 6, are provided will be described. The number of auxiliary injection holes 7 is the same as the number of intake valve vertical movement concave portions 3 and the number of exhaust valve vertical movement concave portions 13. In this embodiment, the number is two. The position of the auxiliary injection port 7 is set in a certain direction of the intake valve vertical movement concave portion 3 and the exhaust valve vertical movement concave portion 13.
At the position where the auxiliary injection hole 7 is bored, the intersection of the center line of the auxiliary injection hole 7 and the inner wall of the cylinder liner 1 is 1/2 of the top clearance.
It is configured to be

The main injection port 6 and the sub injection port 7 are perforated at upper and lower positions as shown in FIG. Further, the main injection port 6 is bored at a position that divides the circumference into eight equal parts with the injection port diameter m being large. Further, the auxiliary injection port 7 is bored at a position above the main injection port 6 with the injection port diameter n being small. The angle a formed by the main injection port 6 is smaller than the angle b formed by the sub injection port 7.
With this configuration, as shown in FIGS. 8 and 9, the fuel spray flow 9 from the sub injection port 7 is sprayed upward in a thin and long manner, and the fuel spray flow 8 from the main injection port 6 is thick and short and It is configured to be sprayed toward the perforated concave portion at the top.

The fuel spray flow 9 discharged from the auxiliary injection port 7 of the present invention is directed toward the intake valve vertical movement recess 3 and the exhaust valve vertical movement recess 13, and the fuel spray flow 9 is the fuel spray flow 8. It was possible to construct a longer reach. As described above, the effect obtained by constructing the main injection port 6 and the sub injection port 7 is that a diesel engine in which the exhaust color does not increase even when the output is reduced as shown in FIG.

[0018]

Since the present invention is constructed as described above, it has the following effects. According to the first aspect of the present invention, it is possible to prevent a part of the flow of the inflowing air from the intake port 5 from colliding with the intake valve vertical movement recessed portion 3, so that the apparent cross-sectional area of the port is reduced. However,
By smoothly aligning the flow line of the intake flow, the flow line d of the intake flow that stagnates and the flow line g of the intake flow that tries to return to the main line are eliminated, and the intake air amount is increased. This allows
Since the amount of inflowing air can be increased, fuel consumption and heat load can be reduced, and deterioration of exhaust color can be prevented.

According to the second aspect of the invention, since the spray reaching distance can be sufficiently obtained, good combustion can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a cylinder liner 1 and a valve seat 4 of the present invention.

FIG. 2 is a partial side sectional view of a valve seat 4, a cylinder liner 1 and an intake valve 2 of the present invention.

FIG. 3 is a drawing showing a relational position between an intake valve seat 4 and an intake port 5 of the present invention.

FIG. 4 is an overhead view showing the streamline of the intake air flow of the present invention.

5A and 5B are a plan view and a side view showing a related position of a conventional intake valve seat 4 and an intake port 5.

FIG. 6 is an overhead view showing a streamline of a conventional intake air flow.

FIG. 7 is a drawing showing a comparison of intake flow rates between the shape of the intake port 5 of the present invention and the shape of the conventional intake port 5.

FIG. 8 is a side view showing a fuel spray flow of the invention in which a main injection port 6 and a sub injection port 7 are provided.

FIG. 9 is a plan view of the fuel spray flow of the main injection port 6 and the sub injection port 7 in the same manner.

FIG. 10 is a side cross-sectional view showing the positional relationship between the sub injection port 7 and the main injection port 6.

FIG. 11 is a drawing showing the relationship between output and exhaust color between the present invention and a conventional structure.

[Explanation of symbols]

 1 Cylinder liner 2 Intake valve 3 Intake valve vertical movement recess 4 Intake valve seat 5 Intake port 6 Main injection port 7 Sub injection port 8 Fuel spray flow 9 Fuel spray flow 13 Exhaust valve vertical movement recess 14 Exhaust valve seat 15 Exhaust port

Claims (2)

[Claims] 1. An outer periphery of a valve seat 4 of an intake valve 2 projects outside the outer periphery of a cylinder liner 1 of an internal combustion engine,
An intake port 5 communicating with a valve seat 4 of the intake valve 2 in a structure in which an intake valve vertical movement recess 3 that allows the intake valve 2 to move vertically is provided at the upper end of the cylinder liner 1.
The diesel engine is characterized in that the outlet side of the intake valve vertical movement concave portion 3 is not provided, and the shape is along the arc outer periphery of the cylinder liner 1 below the valve vertical movement concave portion 3. 2. In an internal combustion engine having a secondary injection port 7 in addition to the main injection port 6 as the injection port of the fuel valve, the auxiliary injection port 7 has a smaller injection port diameter than the main injection port 6, and the auxiliary injection port 7 is the main injection port. A diesel engine, characterized in that the auxiliary injection port 7 is larger than the injection port angle of the injection port 6 and is arranged on the center line of the intake valve vertical movement recessed portion 3 of the cylinder liner 1.