JPH0335850Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a scavenging air control device used in a two-stroke diesel engine.

(Prior Art) One method for improving the performance of two-stroke diesel engines is to improve the performance of two-stroke diesel engines.
A so-called scavenging control valve is known that closes part or all of the engine piston during most of its expansion stroke and opens during the final portion of the expansion stroke and during the compression stroke.

(Problems to be solved by the invention) Conventional scavenging control valves are driven by a separately provided drive source such as electricity or hydraulic pressure, making the mechanism complex and expensive, making them virtually impossible to put into practical use. The actual situation is that it is not.

This invention was proposed in view of the above, and
The purpose is to provide an extremely simple and practical scavenging air control device that can be driven without requiring a separate drive source.

(Means for solving the problem) The present invention is based on a system in which the in-cylinder gas pressure of a two-stroke diesel engine changes continuously from a value sufficiently high to a value slightly lower than the scavenging pressure, and this is repeated in the same mode. It was developed with an eye to the fact that the scavenging port area is partially or completely opened and closed, and an actuator cylinder into which cylinder gas is introduced. A scavenging device comprising a scavenging port opening/closing member for opening and closing part or all of a scavenging port area, and an actuator piston that is slidably fitted in the actuator cylinder in a sealed manner and operatively connected to the scavenging port opening/closing member. A port opening/closing driver; and a return spring interposed between the scavenging port opening/closing driver and the actuator cylinder to bias the scavenging port opening/closing member in a direction to open the scavenging port. The main feature is the scavenging air control device.

(Function) Since the present invention has the above configuration, when the cylinder gas pressure is sufficiently higher than the scavenging pressure during the expansion stroke of the engine piston, this cylinder gas pressure is activated by the actuator. The actuator piston is introduced into the cylinder and pushed against the scavenging pressure and return spring acting on it, and the scavenging port opening/closing member interlocked with the actuator piston is moved forward, thereby opening the scavenging port area. This helps extend the working period of the engine piston during the expansion stroke.
Then, when the cylinder gas pressure decreases at the end of the expansion stroke and the difference between it and the scavenging pressure becomes small, the return spring causes the actuator piston and the scavenging port opening/closing member interlocked therewith to move back to open the scavenging port. Part or all of the area is opened to allow sufficient scavenging air to flow into the engine cylinder.

(Embodiment) An embodiment of the present invention is shown in FIGS. 1 and 2.

In FIGS. 1 and 2, 1 is an engine cylinder, 2 is an engine piston, and 3 is an actuator ring, which are arranged in the middle of the outer circumference of the engine cylinder 1. As shown in FIG. A plurality of actuator cylinders 4 are bored at intervals along the circumferential direction of the actuator ring 3, and extend upward from the lower surface of the actuator ring 3 along the axial direction of the engine cylinder 1. It is growing to Reference numeral 5 denotes an actuator piston that is slidably inserted in the actuator cylinder 4 in a sealed manner, and is interlocked and connected via an arm 8 to a scavenging port opening/closing member 6 that opens and closes the scavenging port 7 . 13 is a piston ring attached to the actuator piston 5. The actuator piston 5, arm 8, piston ring 13, and scavenging port opening/closing member 6 constitute a scavenging port opening/closing drive body. Reference numeral 9 denotes a return spring made of a tension spring that biases the scavenging port opening/closing member 6 in the direction in which the scavenging port 7 opens. It is placed under tension. 11
1 is a gas passage that opens in the middle of the engine cylinder 1 and introduces cylinder gas pressure into the actuator cylinder 4; 12 is a top ring attached to the engine piston 2; It is a seal ring attached to the outer periphery of the

As shown in FIG. 3, the cylinder gas pressure A changes continuously in accordance with the crank angle, and this change is repeated in the same mode. In addition, in FIG. 3, b is the scavenging pressure, which is almost constant.

During the expansion process of the engine piston 2, when the top ring 12 passes through the opening of the gas passage 11 at point A, the cylinder gas pressure of pressure P _A enters the actuator cylinder 4 through the gas passage 11.
The actuator piston 5 is pushed down against the scavenging pressure and the push-up force of the return spring 9. Then, the port opening/closing member 6 descends via the arm 8, thereby closing the upper part of the scavenging port 7.

When the engine piston 2 further descends and the top ring 12 reaches point B, the cylinder gas pressure becomes P _B. Then, the upward force due to the scavenging pressure and the upward force due to the return spring 9 overcome the force due to the cylinder gas pressure P _B , and the actuator piston 5 and the scavenging port opening/closing member 6 slowly rise and return to the position shown by the broken line. , the scavenging port 7 is fully opened, and sufficient scavenging air is supplied into the engine cylinder 1. Then, in the compression process of the engine piston 2, the cylinder gas pressure rises again, but the spring returns it so as to overcome the cylinder gas pressure P _AU when the top ring 12 passes point A while the engine piston 2 is rising. By setting the spring force 9, the scavenging port 7 can be kept fully open.

Note that at point A, where the top ring 12 passes through the opening of the gas passage 11, the in-cylinder gas pressure P _A at point A when the engine piston 2 is descending is equal to the in-cylinder gas pressure P _AU at point A when the engine piston 2 is ascending. The spring force of the return spring 9 and the stroke of the actuator piston 5 must be adjusted in advance.

(Effects of the invention) In the present invention, the scavenging port opening/closing member can be moved forward using the cylinder gas pressure, and the scavenging port opening/closing member can be moved back using the return spring. Unlike valves, it does not require a separate drive source such as electricity or hydraulic pressure. Therefore, the structure is extremely simple, there are few failures, and the cost is low, making it possible to put it into practical use.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention,
Fig. 1 is a front view showing the right half as a cross section, Fig. 2 is a partially enlarged sectional view of Fig. 1, and Fig. 3 is a diagram showing the relationship between crank angle, cylinder gas pressure, and scavenging pressure. . Scavenging port...7, Scavenging port opening/closing member...
6. Actuator cylinder...4. Actuator piston...5. Return spring...9.

Claims (1)

[Scope of utility model registration request] an actuator cylinder into which cylinder gas is introduced; a scavenging port opening/closing member that opens and closes part or all of the scavenging port area; and a scavenging port opening/closing member fitted into the actuator cylinder in a sealed and slidable manner. a scavenging port opening/closing drive body including an actuator piston interlocked with the scavenging port opening/closing member interposed between the scavenging port opening/closing drive body and the actuator cylinder, and the scavenging port opening/closing member opening the scavenging port. A scavenging air control device characterized by comprising a return spring that biases the air in a direction.