JPS627918A - Two-cycle internal-combustion engine with exhaust valve hydraulic driving device - Google Patents

Abstract

PURPOSE:To prevent an operating gas from mixing in during a compression stroke by returning an operating gas piston to an operating gas hole during the scavenging operation, in a two-cycle engine in which an exhaust valve is drived by the hydraulic pressure. CONSTITUTION:An exhaust valve 13 provided on the top part of a two-cycle engine 11 is opened for its operation by supplying a pressured oil to a piston 18 provided at its end part. When a piston 12 comes down to allow a hole 41 on the side wall to open, the gas in the combustion chamber enters a cylinder 43 to push a piston 42 and a small piston 44 so as to generate an oil pressure, and then at the time of opening of a closing valve 47 the oil pressure is introduced through a pipe 46 into a cylinder 17 to open the exhaust valve 13. When a pressure in the combustion chamber drops during the stroke of scavenging, the piston 42 is pushed back by a spring 45, combustion gas in a hydraulic pump 43 is discharged and then into inside of a plunger chamber 62 is supplied an oil from a pump 67 through a check valve 63.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a two-stroke internal combustion engine, and more particularly to a two-stroke internal combustion engine with an exhaust valve hydraulic drive.

[Conventional technology]

FIG. 2 shows an example of a conventional two-stroke internal combustion engine.

This device moves the piston 12 inside the cylinder block 11.
is designed to reciprocate, and there is an exhaust valve 13 at the top,
An exhaust valve box 15 having a bush 14 for holding the exhaust valve 13 is installed.

The upper part of the piston 12 is the combustion chamber 10, and the exhaust valve box 15
An exhaust passage 19 is provided.

The exhaust valve 13 includes a valve spring 16 and a hydraulic actuator A.
A hydraulic cylinder 17 and a hydraulic piston 18 that slide within the hydraulic cylinder 17 are attached.

Further, a working gas hole 41 is formed above the scavenging hole 40 provided in the lower part of the cylinder block 11, and the working gas hole 41 has a working gas piston 42 therein. A hydraulic pump 43 attached to the cylinder is connected to the cylinder so that the inside of the cylinder is communicated with each other.

The working gas piston 42 drives a plunger 44 having a smaller diameter than the working gas piston 42 by pressurization through the working gas hole 41 and is returned by a spring 45 .

The hydraulic pump 43 is connected to the hydraulic cylinder 17 via a high-pressure pipe 46, and a rotary control valve 47 driven by a crankshaft of an engine (not shown) is provided in the middle of the high-pressure pipe 46.

The outside of the scavenging hole 40 is a scavenging chamber 50.

In this way, the hydraulic pump 43. High pressure pipe 46. The hydraulic actuator A constitutes an exhaust valve hydraulic drive device S.

The internal combustion engine configured in this manner operates as follows. That is, in the state shown in FIG. 2, the exhaust valve 13 is closed by the valve spring 16, and the working gas piston 42 is closed.
is pressed toward the working gas hole 41 by a spring 45. Here, the combustion chamber 10 in which the piston 12 descends
Consider the expansion stroke of.

When the crank angle advances from the state where the working gas hole 41 is closed by the piston 12 and the expansion stroke of the working gas in the combustion chamber 10 progresses, and the piston 12 opens the working gas hole 41, the high pressure in the combustion chamber 10 increases. The working gas of the hydraulic pump 4
3, high pressure flows into the working gas piston 42
It acts on

The plunger 44 is driven by the working gas piston 42 to discharge high-pressure working oil, and this working oil causes #
Air valve 13 opens. At this time, the rotary control valve 47 is open.

After the exhaust valve 13 is opened, the rotation control valve 47 is closed at a predetermined crank angle.

By opening the exhaust valve 13, the exhaust action progresses, and the combustion chamber 10
Although the pressure of the working gas inside decreases, since the rotary control valve 47 is closed, the hydraulic cylinder 17 is kept at a high pressure and the exhaust valve 13 continues to open.

As the crank angle further advances, the piston 12 moves into the scavenging hole 40.
When opened, a scavenging action within the combustion chamber 10 takes place.

That is, the scavenging air in the scavenging chamber 50 flows into the combustion chamber 10 from the scavenging hole 40, and the working gas in the combustion chamber 10 flows out from the exhaust valve 13 into the exhaust passage 19.

When the crank angle passes the bottom dead center and the piston 12 begins its upward stroke, and the piston 12 closes the scavenging hole 40 and completes the scavenging action, when the crank angle reaches a predetermined crank angle, the rotary control valve 4
Open 7.

As a result, the #air valve 13 begins to close due to the force of the valve spring 16, and as the hydraulic piston 18 rises, the hydraulic pump 4
3 plunger 44 is driven by hydraulic pressure from high pressure pipe 46 and cooperates with the force of spring 45 to drive actuating gas piston 42 to the distal position of actuating gas hole 41 .

As a result, the exhaust valve 13 closes, and a compression stroke begins as the piston 12 within the combustion chamber 10 rises, leading to a combustion stroke and an expansion stroke.

[Problem that the invention seeks to solve]

However, when using such an internal combustion engine, there are the following problems.

In other words, the crank angle has passed the bottom dead center and the piston 12
The state of the hydraulic pump 43 immediately after closing the scavenging hole 40 is as follows.
The result is as shown in FIG.

At this time, since the working gas piston 42 is pressed in the direction of the plunger 44 by the pressure of the scavenging air in the combustion chamber 10 against the force of the spring 45, there is a space between the working gas hole 41 and the working gas piston 42. 51 has occurred.

By the way, the working gas that finally flows in when the exhaust valve 13 is opened is accumulated in this space 51. others
- When the exhaust valve 13 closes, the rotary control valve 47 opens and the working gas piston 42 is driven to the position of the working gas hole 41, and the working gas in this space 51 flows into the combustion chamber 10.
flow back inside.

At this time, the scavenging hole 40 has already been closed and the scavenging action has ended, so the working gas that has flowed back into the combustion chamber 10
The scavenging air remains in the combustion chamber 10 and participates in the next compression stroke, reducing the purity of the scavenging air in the combustion chamber 10, lowering the scavenging efficiency, and causing poor combustion.

The present invention aims to solve these problems, and by returning the working gas piston to the working gas hole during scavenging, it is possible to prevent the working gas from flowing back during the compression stroke, thereby improving combustion. An object of the present invention is to provide a two-stroke internal combustion engine with an exhaust valve hydraulic drive device that improves the scavenging efficiency in a room.

[Means for solving problems]

For this reason, the two-stroke internal combustion engine with an exhaust valve hydraulic drive device of the present invention is a two-stroke internal combustion engine that includes an exhaust valve attached to the cylinder and an exhaust valve hydraulic drive device for driving the exhaust valve. , the exhaust valve hydraulic drive device is interposed between a hydraulic pump driven by the inflow of working gas into the combustion chamber in the cylinder, and the hydraulic pump and the exhaust valve, and the exhaust valve hydraulic drive device is installed between the hydraulic pump and the exhaust valve to drive the exhaust valve by the output hydraulic pressure of the hydraulic pump. and a hydraulic actuator capable of opening and driving a valve, the hydraulic actuator is configured to pressurize the hydraulic pump in order to return the working gas that has flowed into the hydraulic pump during the scavenging stroke of the internal combustion engine into the combustion chamber. A return hydraulic oil supply system capable of supplying hydraulic oil at atmospheric pressure or higher into the room, a reverse valve that prevents hydraulic oil from flowing back into the return hydraulic oil supply system, and the hydraulic actuator associated with the closing operation of the exhaust valve. It is characterized by the addition of an oil drainage system that allows the backflow of hydraulic oil from.

[For production]

In the two-stroke internal combustion engine with the exhaust valve hydraulic drive device of the present invention described above, working gas is returned from the exhaust valve hydraulic drive device during the scavenging stroke, and backflow of the working gas during the compression stroke is prevented.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
FIG. 1 is a longitudinal cross-sectional view of essential parts showing a two-stroke internal combustion engine as an embodiment of the present invention.

The internal combustion engine of this embodiment has almost the same structure as the conventional example shown in FIG. 2, except for one part of the exhaust valve hydraulic drive device. In FIG. 1, the same reference numerals as in FIG. It shows something almost similar.

The exhaust valve hydraulic drive device S in this embodiment includes the tip of the plunger 44 in the hydraulic pump 43 and the high pressure pipe 46.
An oil drain hole 64 is attached to the plunger chamber 62 as a pressurized chamber formed between the plunger chamber 62 and a check valve 63 in parallel with the oil drain system B formed by the floating oil hole 64. A return hydraulic pressure supply system C is attached.

In the oil drain system B, the hydraulic oil is returned to the oil tank 66 via the pipe 65 through the oil drain hole 64, and on the other hand, in the return hydraulic supply system C, the hydraulic oil in the oil tank 66 is returned to the oil tank 66. , the pressure accumulator 68 . by the pump 67 . It is supplied to the plunger chamber 62 via a check valve 63.

Note that the pump 67 is configured to be able to supply hydraulic oil at atmospheric pressure or higher.

Since the two-stroke internal combustion engine with an exhaust valve hydraulic drive device as an embodiment of the present invention is configured as described above,
When the exhaust valve 13 is opened, the piston 12 opens the working gas hole 41 (then the high pressure working gas in the combustion chamber 10 flows in, and high pressure acts on the working gas piston 42).

Operation: Plunger 4 driven by piston 42
4 first closes the oil drain hole 64 and then closes the plunger chamber 62.
Since the hydraulic oil is compressed, the check valve 63 is closed, high-pressure hydraulic oil is supplied to the hydraulic cylinder 17 via the rotary control valve 47, and the exhaust valve 13 is opened.

After the exhaust valve 13 is opened, the rotary control valve 47 is closed, so the exhaust valve 13 continues to open thereafter.

Then, when the exhaust action progresses by opening the exhaust valve 13 and the working gas pressure in the combustion chamber 10 decreases, the force acting on the actuating piston 42 becomes smaller and the plunge middle chamber 6
The pressure of the hydraulic oil inside 2 also decreases.

As a result, at the time when the piston 12 opens the scavenging hole 40 and the scavenging action starts, the discharge pressure of the pump 67 acting on the check valve 63 is higher than the hydraulic oil pressure in the plunger chamber 62. Then, the check valve 63 opens, hydraulic oil flows into the plunger chamber 62, and the working gas piston 42 is driven toward the working gas hole 41.

The working gas piston 42 has a plunger 44 connected to an oil drain hole 64.
It is driven open until the working gas is returned into the combustion chamber 10.

Then, as the crank angle advances and the rotation control valve 47 opens,
The exhaust valve 13 begins to close due to the force of the valve spring 16. At this time, the high pressure pipe 46 is discharged as the hydraulic piston 18 rises. The hydraulic oil in the hydraulic cylinder 17 flows back from the rotary control valve 47 to the plunger chamber 62, but this backflow is allowed by the oil drain system B with the oil drain hole 64, and the hydraulic oil is returned to the oil tank 66. Then, the exhaust valve 13 returns to the state shown in FIG. 1 before it was opened.

Note that when the plunger 44 opens the oil drain hole 64, the hydraulic oil from the pump 67 flows through the check valve 63 and the plunger chamber 62. The oil is circulated through the oil drain hole 64 to the oil tank 66.

By such an operation, the working gas piston 42 is driven toward the working gas hole 41 at the time when the scavenging action is started, when the working gas pressure in the combustion chamber 10 is reduced.

As a result, the working gas in the space 51 shown in FIG. 3 flows back into the combustion chamber 10 at the time when the scavenging action starts, and is therefore discharged from the combustion chamber 10 to the exhaust passage 19 by the scavenging air flowing in from the scavenging hole 40. Ru.

Therefore, the working gas in the space 51 does not reduce the scavenging efficiency, improving the scavenging efficiency and improving combustion.

Further, since the hydraulic oil in the plunger chamber 62 is circulated to the oil tank 66, its temperature does not rise even if the plunger 44 repeatedly compresses and expands.

〔Effect of the invention〕

As described in detail above, according to the two-stroke internal combustion engine with an exhaust valve hydraulic drive device of the present invention, the two-stroke internal combustion engine has an exhaust valve attached to the cylinder and an exhaust valve for driving the exhaust valve. a hydraulic pump, the exhaust valve hydraulic drive device being interposed between the hydraulic pump and the exhaust valve, the hydraulic pump being driven by the inflow of working gas into the combustion chamber in the cylinder; and a hydraulic actuator capable of driving the exhaust valve to open with an output hydraulic pressure of the internal combustion engine; A return hydraulic supply system that can supply hydraulic oil at atmospheric pressure or higher into the pressurizing chamber of the hydraulic pump, a check valve that prevents hydraulic oil from flowing back into the return hydraulic supply system, and a closing operation of the exhaust valve. With a simple configuration in which an oil drainage system that allows backflow of hydraulic oil from the hydraulic actuator is added, scavenging efficiency is improved and combustion conditions are improved.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a main part showing a two-stroke internal combustion engine as an embodiment of the present invention, and FIGS. 2 and 3 show a conventional two-stroke internal combustion engine, and FIG. FIG. 3 is a longitudinal sectional view of a main part showing its operating state. 10... Combustion chamber, 11... Cylinder block, 12...
Piston, 13... Exhaust valve, 14... Bush, 15...
・Exhaust valve box, 16...valve spring, 17...hydraulic cylinder,
18...Hydraulic piston, 19...Exhaust passage, 40...Scavenging hole, 41...Working gas hole, 42...Working gas piston, 43...φ hydraulic pump, 44...Plunger, 45...
Spring, 46... High pressure pipe, 47... Rotary control valve, 50...
Scavenging chamber, 51... Space, 62... Plunger chamber as pressurizing chamber, 63... Check valve, 64... Oil drain hole, 65... Piping, 66... Oil tank, 67... Pump, 68 ... Pressure accumulator, A.. Hydraulic actuator, B.. Hydraulic thread, C.
・Return hydraulic supply system, S...Exhaust valve hydraulic drive device. Sub-Agent Patent Attorney Yoshihiko Iinuma Figure 1 Figure 2 Δ

Claims (1)

[Claims] A two-stroke internal combustion engine includes an exhaust valve attached to the cylinder and an exhaust valve hydraulic drive device for driving the exhaust valve, and the exhaust valve hydraulic drive device controls the inflow of working gas into the combustion chamber of the cylinder. and a hydraulic actuator that is interposed between the hydraulic pump and the exhaust valve and can drive the exhaust valve to open using the output hydraulic pressure of the hydraulic pump, In order to return the working gas that has flowed into the hydraulic pump into the combustion chamber during the scavenging stroke, the hydraulic pump is provided with:
A return hydraulic supply system that can supply hydraulic oil at atmospheric pressure or higher into the pressurizing chamber of the hydraulic pump, a check valve that prevents hydraulic oil from flowing back into the return hydraulic supply system, and a closing operation of the exhaust valve. A two-stroke internal combustion engine with an exhaust valve hydraulic drive device, characterized in that the engine is equipped with an oil drainage system that allows backflow of hydraulic oil from the hydraulic actuator.