JPH06221220A - Scavenging flow control device for diesel engine - Google Patents

Abstract

PURPOSE:To unify distribution in cylinder liner circumferential direction of scavenging air in a scavenging chamber, and eliminate eccentricity of swirl in a cylinder so as to improve scavenging efficiency, in a two cycle diesel engine. CONSTITUTION:A guide plate 12 provided with a plurality of guide vanes 12a, 12b for controlling direction of scavenging flow is provided on the scavenging flow inlet 15 of a scavenging chamber so as to unify distribution of scavenging air in circumferential direction of a cylinder liner 1 in the scavenging chamber by a control plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scavenging device for a two-cycle diesel engine mainly used as a marine main engine.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. FIG. 4 is a cross-sectional view including the cylinder axis of the two-cycle diesel engine, and FIG. 5 is a cross-sectional view showing the state of scavenging flow in a cross section perpendicular to the cylinder axis of the scavenging chamber.

In the figure, 1 is a cylinder liner, 2 is an exhaust valve, 3 is a piston, and 5 is a scavenging port. In order to give a swirling flow to the scavenging air during the scavenging process, a plurality of scavenging ports 5 are arranged in the circumferential direction and an appropriate twist angle is given. If the flow rate of air flowing into the scavenging port 5 is uniform in the circumferential direction, the inflow velocity will also be uniform in the circumferential direction, and the swirl axis of the swirl in the cylinder will be substantially equal to the axis of the cylinder liner.

In FIG. 5, which is a cross section perpendicular to the axis of the cylinder liner, 1 is a cylinder liner, 5 is a scavenging port,
6 is a cylinder jacket, 7 is a scavenging trunk, 10 is a scavenging chamber, and 15 is an air inlet for connecting the scavenging chamber 10 and the scavenging trunk 7. In the figure, the scavenging ports 5 are evenly arranged in the circumferential direction, and the scavenging chamber 1 is connected to the scavenging trunk 1 through the scavenging trunk 7.
In the direction of the scavenging flow 9 flowing into 0, as shown in the figure, it is perforated so as to be inclined in one direction. 11 is the center of swirl.

[0005]

However, in the conventional scavenging chamber structure of the diesel engine, the scavenging flow 9 has an inflow passage from the scavenging trunk 7 to the scavenging chamber 10 of the cylinder jacket 1 as shown by an arrow in the figure. Since only one place can be arranged, as shown by E in the same figure, between the scavenging port 5 facing the inflow direction of the scavenging air and the scavenging port 5 not facing shown in F in the drawing, it is shown. Such an imbalance occurs in the inflow speed. As a result, the swirl center 11 formed in the cylinder is pressed by the scavenging air having a large inflow velocity flowing from the scavenging port 5 at the E position, and is eccentric in the F position direction as shown in the figure, so that the scavenging efficiency is deteriorated. There was a drawback that reduced the engine performance.

The object of the present invention is to solve the problems of the conventional device, eliminate the eccentricity of the swirl center in the cylinder, and smoothly perform the exhaust gas exchange action by scavenging, so that the engine performance can be improved. To provide the scavenging chamber structure.

[0007]

According to the present invention, a guide vane having a plurality of guide plates for controlling the flow direction of the scavenging air flow is provided at a scavenging air flow inlet which connects the scavenging trunk and the scavenging chamber. I am trying.

More specifically, the guide vanes are
A forward guide vane that is provided at a position facing the scavenging port and is directed in the forward direction of the scavenging port, and a backward guide vane that is provided at a position away from the scavenging port and is directed in the opposite direction of the scavenging port. It consists of and.

[0009]

[Operation] In the direction of the swirl in the cylinder, the scavenging air inlet 15
Forward guide vanes 12a to the scavenging port group 5a close to
From the reverse guide vane 12b flows into the scavenging port group 5b away from the scavenging air inlet. As a result, the distribution of the scavenging air in the scavenging chamber 10 is made uniform, and the center of the swirl in the cylinder does not decenter from the center of the cylinder as in the conventional one, and high scavenging efficiency can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 (a) is a sectional view perpendicular to the cylinder axis of a scavenging chamber, and FIG. 1 (b) is FIG. It is a A arrow line view of (a).

In FIGS. 1 and 2, 1 is a cylinder liner,
5 is a scavenging port formed in the lower portion of the cylinder liner 1 at equal intervals in the circumferential direction, 6 is a cylinder jacket, 7 is a scavenging trunk, 10 is a scavenging chamber divided into cylinders, and 15 is a scavenging trunk 7 And the scavenging chamber of each cylinder, which is a scavenging air inlet.

Reference numeral 12 is a guide plate provided at each scavenging air flow inlet. The guide plate 12 is, as shown in FIG.
The upper half of that is a plurality of forward guide vanes 12a,
The lower half is composed of a plurality of reverse guide vanes, and a partition plate 13 partitions the forward guide vanes 12a and the reverse guide vanes 12b.

As shown in FIG. 1 (b), the forward guide vanes 12a are arranged in a portion facing the scavenging port 5 in the axial direction of the cylinder, and are directed in the forward direction of the swirl flow in the cylinder. .

The reverse guide vanes 12b are
As shown in FIG. 1 (b), it is arranged at a position apart from the scavenging port 5 in the axial direction of the cylinder, and is directed in the opposite direction of the in-cylinder swirl.

In the diesel engine having the above structure, the scavenging air introduced from the supercharger (not shown) into the scavenging trunk 7 flows into the scavenging chamber 10 through the space between the guide vanes of the guide plate 12. .

At this time, the scavenging air flowing into the scavenging chamber 10 from the scavenging air inlet 15 is the partition plate 13 of the guide plate 12.
The scavenging air from the forward guide vanes 12a flows into the scavenging port group 5a near the scavenging air inlet 15 in the direction of the in-cylinder swirl, and into the scavenging port group 5b away from the scavenging air inlet. , Reverse guide vane 12b
The scavenging air from

As a result, the distribution of the scavenging air flow in the scavenging chamber 10 is made uniform, and the center of the swirl in the cylinder does not decenter from the center of the cylinder as in the conventional case, and high scavenging efficiency can be obtained.

FIG. 2 shows a modification of the embodiment shown in FIG. In this case, the guide plate 12 is rotatably attached around the pin 21 to improve the maintainability of the scavenging chamber 10.

FIG. 3 shows another embodiment of the present invention. In this embodiment, the guide plate 12 is twisted at a substantially central portion in the axial direction of the cylinder. The guide vanes 12b are formed.

[0020]

Since the present invention is configured as described above, the scavenging air flow uniformly flows into the scavenging chamber from the forward guide vanes and the backward guide vanes, and the distribution of the scavenging air inside the scavenging chamber is made uniform. To be done. As a result, unlike the conventional one, the center of the swirl in the cylinder does not decenter from the center of the cylinder, and high scavenging efficiency can be obtained.

[Brief description of drawings]

FIG. 1 (a) is a sectional view perpendicular to the cylinder axis showing a first embodiment of the present invention.

FIG. 1 (b) is a view on arrow A of FIG. 1 (a).

FIG. 2 is a correspondence diagram of FIG. 1 (a) showing another embodiment of the present invention.

FIG. 3 is a correspondence diagram of FIG. 1 (b) showing another embodiment of the present invention.

FIG. 4 is a vertical sectional view of a cylinder showing an embodiment of the present invention.

FIG. 5 is a correspondence diagram of FIG. 1 (a) showing a conventional example.

[Explanation of symbols]

1 ... Cylinder liner, 5 ... Scavenging port, 10 ... Scavenging chamber,
12 ... Guide plate, 12a ... Forward guide vane, 12b
... Reverse direction guide vanes, 13 ... Partition plate, 15 ... Scavenging air inlet.

Claims (3)

[Claims] 1. A two-cycle diesel engine configured to introduce scavenging air into a scavenging chamber into the cylinder liner from a plurality of scavenging ports formed in the lower portion of the cylinder liner, and to connect the scavenging trunk and the scavenging chamber. A scavenging air flow control device for a diesel engine, wherein a guide plate having a plurality of guide vanes for controlling the flow direction of the scavenging air flow is provided at a scavenging air flow inlet. 2. The guide plate is disposed in a portion facing the scavenging port in the axial direction of the cylinder liner, a forward guide vane oriented in the forward direction of the scavenging port, and a portion distant from the scavenging port. The reverse guide vane arranged in the opposite direction and directed in the direction opposite to the direction of the scavenging port, and a partition plate for partitioning the forward guide vane and the reverse guide vane. Diesel engine scavenging air flow control device. 3. The guide plate twists each guide vane in the axial direction of the cylinder liner, and a portion closer to the scavenging port than the twisted portion is the forward guide vane, and a portion farther from the scavenging port than the twisted portion is the guide plate. The scavenging air flow control device for a diesel engine according to claim 1, wherein the scavenging air flow control device is configured as a reverse guide vane.