JPS62129519A - Scavenging port control type internal combustion engine - Google Patents

Abstract

PURPOSE:To increase a scavenging area to supply much new air into a cylinder so as to enhance scavenging efficiency by forming a scavenging port on a cylinder liner and setting the height of the scavenging port to a particular ratio to the stroke of a piston in the cylinder. CONSTITUTION:Even if the top of a piston 10 descends across the upper end of a scavenging port in the expansion stroke, a check valve 9 is kept closed since the inside of a cylinder chamber 6 is at high pressure by means of burned gas. Further, as the piston 10 descends to reach to vicinity of a bottom dead center and an exhaust valve 2 is opened, the burned gas in the cylinder chamber 6 is exhausted to an exhaust pipe 12 through an exhaust passage 16. At this time, the pressure in the cylinder chamber 6 becomes lower than the pressure in a scavenging chamber 11 pressurized by means of a supercharger 13, and a check valve 9 is opened and the new air in the scavenging chamber 11 flows into the cylinder chamber 6. In this case, the height of the scavenging port 8 is set to 8-24% of the stroke of the piston 10 and the scavenging area is increased to allow much new air to flow into the cylinder chamber 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal combustion engine having a scavenging port in a cylinder liner.

[Conventional technology]

Generally speaking, in internal combustion engines where the cylinder liner is equipped with a scavenging port, the scavenging port is located near the bottom dead center of the piston stroke in the cylinder liner. - 1jiIIL
Scavenging is started when the upper end of the piston passes the upper end of the scavenging port during the downward movement.

At this time, if the combustion gas in the cylinder has a higher pressure than the scavenging air, the combustion gas will cause a backflow from the scavenging port toward the scavenging chamber, reducing the scavenging efficiency. For this reason, the pressure of combustion gas in the cylinder is lowered by opening the exhaust valve at an appropriate timing before the start of scavenging to prevent backflow of combustion gas.

Furthermore, the timing for opening this exhaust valve is set at a time when the piston has descended as far as possible before the start of scavenging, in order to improve the thermal efficiency of the engine. This is to improve the engine's thermal efficiency by increasing the effective stroke, the distance the piston moves from when it passes top dead center until the moment it descends and opens the exhaust valve.

[Problem that the invention seeks to solve]

However, as described above, in an internal combustion engine in which a conventional cylinder liner is provided with a scavenging port, the exhaust port must be opened before the upper end of the piston passes the upper end of the scavenging port F during the expansion stroke. Therefore, the effective stroke of the piston is limited to the distance from the top dead center of the piston to the upper end of the scavenging port.

On the other hand, in order to improve the thermal efficiency of the engine, it is advantageous to make the effective stroke longer. Therefore, in order to further extend the effective stroke Y of the piston in order to further improve the thermal efficiency of the engine, it is conceivable to further reduce the height of the scavenging port.

However, if the height of the scavenging port is reduced, the area of the scavenging port becomes insufficient, leading to a decrease in scavenging efficiency, which is even disadvantageous in terms of the thermal efficiency of the engine metal body. In other words, contradictory conditions are required: in order to improve scavenging efficiency, the height of the scavenging port must be increased, and in order to extend the effective stroke, the height of the scavenging port must be decreased. That's what happens.

The present invention attempts to solve the above-mentioned problems, and aims to reduce the height of the scavenging port by 8 to 24% of the piston stroke.
The scavenging port control type improves the scavenging efficiency by increasing the scavenging port area and extending the piston's effective stroke to improve the thermal efficiency of the engine. The purpose is to provide internal combustion engines.

[Means for solving problems]

Therefore, the scavenging port control type internal combustion engine of the present invention has an internal combustion of 8! Equipped with a scavenging port in the flash cylinder liner,
A control valve for preventing gas from flowing out of the cylinder is provided at or near the scavenging port, and the port is connected to the scavenging port from 8 to 24 degrees of the piston stroke in the cylinder.
It is characterized by being formed to have a height of %.

[Effect]

In the above-mentioned return port control type internal f1 engine of the present invention, the control valve provided at or near the scavenging port of the cylinder liner directs the air into the cylinder at the scavenging port when the scavenging port opens. The inflow of supply air is allowed, but the outflow of gas inside the cylinder to the outside of the cylinder is blocked. With the scavenging port extended to a height of 8 to 24% of the piston stroke, the return air area is expanded and more air is supplied into the cylinder, increasing scavenging efficiency.

〔Example〕

Hereinafter, a scavenging port controlled internal @ engine as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a longitudinal sectional view thereof, and Figs. Figure 2 (a) is an enlarged vertical cross-sectional view of the conventional scavenging port section, Figure 2 (1)) is an enlarged vertical cross-sectional view of the scavenging port section of this embodiment, and fjS3.
The figure is a pv and tQ diagram showing its operating state, and FIG. 4 is a time area diagram showing the opening and closing states of its exhaust valve and scavenging port.

As shown in FIG. 1 and fjS2 (b), a scavenging port 8 of height II is opened at the bottom of the cylinder liner 4, and a piston 10 is slidably inserted into the liner 4. There is. The scavenging port height H is set to 8-24% of the piston stroke.

A cylinder cover 3 is installed above the cylinder liner 4. A hole serving as an exhaust passage 16 from the inside of the cylinder chamber 6 to the exhaust pipe 12 is formed inside the exhaust valve rU1.

An exhaust valve 2 is disposed in the exhaust valve box 1 so as to be slidable in the vertical direction so as to open and close the boundary between the exhaust passage 1G and the inside of the cylinder chamber 6. It is equipped with a mechanism that drives the air pressure valve. Further, the exhaust passage 16 is arranged across the supercharger 13 via the exhaust gas l1712.

Further, a cylinder jacket 5 is connected to the outer periphery of the cylinder liner 4, and a scavenging chamber 11 is formed from the same shaft 5 and the cylinder liner 4 so as to enclose the lower part of the cylinder liner 4. Further, the scavenging chamber 11 communicates with the supercharger 13 via an air reservoir 15 and an air cooler 14.

On the outer side of the scavenging port 8 in the cylinder liner 4,
While the check valve chamber housing 17 is attached, the check valve chamber 7
is formed. The check valve chamber housing 17 is provided with a check valve 9 as a control valve, and this check tr-9 is composed of one elastic check valve plate and a stopper 18.

An air supply flow path (not shown) is formed inside the bar 18, allowing communication between the scavenging chamber 11 side and the scavenging port 8 side. Further, this air supply passage is closed by aligning the check valve plate 19 with the opening on the check valve chamber 7 side of the air supply flow path (each check valve plate 19 indicated by a solid line in the figure).
is in the closed state), check valve plate 1 as shown by the arrow in the figure
9 is opened by elastic deformation (one check valve plate indicated by a broken line in the figure shows the open state). Normally, each check valve plate 19 is in a closed state due to an elastic force that attempts to maintain its planar shape. A plurality of these check valves 9 are arranged vertically and fill the scavenging chamber side opening of the reverse valve chamber housing 17.

The stopper 18 fills the gap between the check valve plates 19 on the side of the scavenging chamber 11 of the check valve chamber 7, while elastically deforming one check valve plate in the opening direction (direction indicated by the arrow in the figure). This prevents excessive deformation of the check valve when

Further, the check valve plate 19 is elastically deformed and opens the it +Th valve 9 only when the pressure in the cylinder chamber 6 becomes lower than the pressure in the scavenging chamber by a certain amount or more.

Since the scavenging port controlled internal combustion engine as an embodiment of the present invention is configured as described above, even if the top of the piston passes the upper end of the scavenging port 8 during the expansion stroke, that is, the downward stroke of the piston, the cylinder chamber 8 Since the inside is under high pressure due to combustion gas, the check valve plate 19 remains in the closed position. At this time, the high-pressure combustion gas in the cylinder chamber G is stopped by the check valve 9 when it enters the scavenging port 8 and the valve chamber 7, and does not flow out into the scavenging chamber 11.

When the piston further descends and reaches near the bottom dead center, the exhaust valve 2 is opened by an exhaust valve drive mechanism (not shown), and the combustion gas in the cylinder chamber 6 is discharged into the exhaust pipe 12 through the exhaust passage 16. be done.

At the same time, the pressure in the cylinder chamber 6 decreases, and the pressure in the cylinder chamber 6 becomes lower than the pressure in the scavenging chamber 11 pressurized by the supercharger 13, and the force due to the pressure difference is It acts on one check valve plate from the scavenging chamber 11 side to the cylinder interior 6 side.

Then, when this force exceeds the elastic force that attempts to maintain the planar shape of one check valve plate, one check valve plate is elastically deformed, and the one-way valve 9 is opened.

With this opening of the check valve 9, fresh air in the scavenging chamber 11 flows into the cylinder chamber 6. At this time, the scavenging port height 11 is more than twice the conventional scavenging port height I-1'(tl' is about 4 to 8% of the piston stroke) shown in Fig. fjS2 (b), The scavenging area increases by this amount, and a larger amount of fresh air flows into the cylinder chamber 6. Therefore, the efficiency of scavenging air is greatly improved, contributing to an improvement in the thermal efficiency of the engine.

In addition, the reference numeral 4' shown in FIG. 2(a) is a conventional cylinder liner, the reference numeral 6' is a conventional cylinder chamber, the reference numeral 8' is a conventional scavenging port, the reference numeral 10' is a conventional piston, and , 11' indicate conventional scavenging chambers, respectively.

This scavenging action occurs when the piston 10 closes the exhaust valve 2.
begins to rise, and ends with the scavenging port 8 being closed due to this rising of the piston 10. Then, the process moves on to compression, combustion, and expansion.

In this way, the scavenging area is increased by the action of the check valve 9, and an effective stroke can be performed while improving the scavenging efficiency.

FIG. 3 is a pv diagram showing the operating state of the scavenging port control type internal combustion engine of this embodiment, and the horizontal axis represents the volume ■.

The pressure P is plotted on the vertical axis. And the solid line u-1 in the figure
)-c-d e fa-a shows the pv diagram of the scavenging port controlled internal combustion engine of the present invention, and the broken line a'I)'-
c-d-e'-V-n' shows a pv diagram of a conventional internal combustion engine. Further, Vll indicates the volume of the combustion chamber when the piston 10 is at the bottom dead center.

Conventionally, the expansion stroke of the engine was terminated at the point 1 indicated by the sign e' of the convergence plane reaching the combustion chamber volume V11 (at this time, the scavenging port was opened), but according to this embodiment, , even though the scavenging port height I-1 has increased, the opening of the scavenging port 8 is delayed, so as shown by symbol C, the expansion stroke is performed up to the volume V11.

Figure 4 shows a time-area diagram of the scavenging port and exhaust valve, where the horizontal axis represents time (time elapses toward the right) and R
Each opening amount is taken on the axis. In addition, actual jQ C and E are scavenging ports 18. The exhaust valve 2 is shown with S/○ when the scavenging port 8 is open, S/C when it is closed, Elo when the exhaust valve 2 is open, and E/C when it is closed.
are shown respectively. In addition, the dashed line F is the conventional scavenging port.

The exhaust valve is shown.

In this embodiment, as the timing of opening the scavenging port 8 is delayed, in order to secure the required amount of air in the cylinder,
The timing of closing the scavenging port and closing the exhaust valve is also delayed.

As a result, the start of the compression stroke is also delayed from a' to a in the figure, as shown in FIG. Therefore, the illustrated effective work increases by the amount shown in the shaded area and the shaded area B in FIG. Only this increase in indicated effective work improves the thermal efficiency of the system.

In this way, the thermal efficiency of the engine is greatly improved by increasing the effective stroke.

In addition to the check valve shown in this embodiment, the control valve 'C of the present invention uses a solenoid valve or the like that senses the vertical movement of the piston and opens and closes at appropriate timing in synchronization with the vertical movement of the piston. You may.

〔Effect of the invention〕

As described in detail above, according to the scavenging port controlled internal combustion engine of the present invention, the scavenging port is provided in the cylinder liner between the internal combustion holes, and the scavenging port or its vicinity is used to block the amount of light emitted from the gas in the cylinder. In addition to providing one control valve, the simple configuration in which the port is formed to have a height of 8 to 24% of the piston stroke inside the cylinder greatly improves scavenging efficiency. The effective stroke of the engine can be extended while
The thermal efficiency of the engine can be greatly improved.

[Brief explanation of drawings]

Figures 11 to 4 show a scavenging port controlled internal combustion engine as an embodiment of the present invention, and Figure 1 is part 1! ttllR
The top view, Figures 2(a) and 2(b) show the scavenging port section in comparison with the conventional example, and Figure 2(,) is an enlarged vertical sectional view of the conventional scavenging port section. Figure 2 (I)) is an enlarged vertical sectional view of the scavenging port section of this embodiment, Figure 3 is a PVi diagram showing its operating state, and Figure fjS4 is a time area diagram showing the opening/closing status of the exhaust valve and scavenging port. It is. 1... Exhaust valve box, 2... Exhaust valve, 3... Cylinder cover, 4, 4'... Cylinder liner, 5... Cylinder jacket, 6, 6'... Cylinder chamber, 7... Stop valve room,
8, 8'...Scavenging port, 9...Stop valve (as a control valve), 10.10'...Piston, 11,11'
...Scavenging chamber, 12..Exhaust pipe, 13..Supercharger, 14
・・Air cooler, 15・・Air reservoir, 16・・Exhaust passage,
17... Reverse IL valve chamber housing, 18... Stopper,
19... Proper valve plate! -I, 11'...Height inside the scavenging air. Sub-Agent Patent Attorney Yoshihiko Iinuma Figure 1

Claims (1)

[Claims] A cylinder liner of an internal combustion engine is provided with a scavenging port, and a control valve is provided at or near the scavenging port to prevent gas from flowing out of the cylinder.
A scavenging port controlled internal combustion engine characterized by being formed to have a height of 4%.