RU2850577C1 - Two-stroke engine with corpusless exhaust device - Google Patents

Abstract

FIELD: internal combustion engines.

SUBSTANCE: invention relates to two-stroke internal combustion engines with devices for regulating the parameters of combustion product efflux. A two-stroke engine with a caseless exhaust device comprises a casing (1) with a cylinder (2) having blow-off ports and at least one exhaust port connected to the atmosphere. The exhaust port is connected to the atmosphere via the cylinder exhaust channel, the exhaust manifold and the exhaust device. The exhaust device (5) is connected to the engine shaft and is designed to create at least some resistance to the movement of combustion products leaving the exhaust manifold (3) during part of the engine's operating cycle. One end of the exhaust manifold (3) is connected to the exhaust channel, and the other end is open, allowing the combustion products to be discharged into the atmosphere directly from the outlet (6) of the manifold. The exhaust device (5) is located outside the engine housing (1) and is installed so that it can act on the flow of combustion products directed into the atmosphere from the outlet (6) of the exhaust manifold.

EFFECT: reduction in engine weight without compromising its specific characteristics.

4 cl, 4 dwg

Description

The invention relates to the field of engine building, namely to two-stroke internal combustion engines with devices for regulating the parameters of the exhaust of combustion products.

A two-stroke engine with an exhaust device is known, comprising a housing with a cylinder having purge ports and at least one exhaust port communicated with the atmosphere via an exhaust channel of the cylinder and an exhaust manifold, as well as a sector rotating device connected to the engine shaft, made with the possibility of influencing with its projection during part of the exhaust process the flow of combustion products exiting the exhaust manifold (RU2017993C1, published 15.08.1994).

The disadvantages of the known engine are its increased weight and manufacturing complexity.

The technical problem is to eliminate the indicated shortcomings.

The technical result is a reduction in engine weight without deteriorating its specific characteristics.

The technical problem is solved and the technical result is achieved in that a two-stroke engine comprises a housing with a cylinder having purge ports and at least one exhaust port communicated with the atmosphere by means of an exhaust channel of the cylinder and an exhaust manifold, as well as an exhaust device connected to the engine shaft, configured to create at least resistance to the movement of combustion products leaving the exhaust manifold during a part of the engine's operating process, wherein, according to the invention, one end of the manifold is communicated with the exhaust channel, and its other end is made open with the possibility of releasing combustion products into the atmosphere directly from the outlet opening of the manifold, the exhaust device is located outside the engine housing and is installed with the possibility of influencing the flow of combustion products directed into the atmosphere from the outlet opening of the exhaust manifold.

The technical result is also achieved by the fact that the exhaust device can be made in the form of a rotating disk with a sector protrusion having a flat control surface, and the open end of the exhaust manifold is located with a gap relative to the control plane of the sector protrusion.

The technical result is also achieved by the fact that the exhaust device can have a rotating cylindrical control surface, and the open end of the exhaust manifold is located with a gap relative to the cylindrical control surface.

The technical result is also achieved in that the exhaust device may contain combustion product flow dividers located with the possibility of influencing the flow before the exhaust device creates resistance to the movement of combustion products from the outlet opening of the manifold.

The invention is explained with the help of drawings.

Fig. 1 – external view of the engine with the exhaust device in the position during free release of combustion products.

Fig. 2 – the same, in the process of creating resistance to the passage of combustion products into the atmosphere.

Fig. 3 – view of the outlet device with a cylindrical control surface.

Fig. 4 – view of the exhaust device with diffusers.

The engine being described comprises a housing 1 with a cylinder 2 having purge ports and at least one exhaust port (not shown in the drawings) communicated with the atmosphere by means of an exhaust channel formed in the cylinder 2 and an exhaust manifold 3. The engine is also provided with an exhaust device 5 connected to the engine shaft 4, configured to create at least resistance to the movement of combustion products leaving the exhaust manifold during a part of the engine operating process. One end of the manifold 3 is connected to the cylinder 2 and communicated with its exhaust channel, and its other end is made open with the possibility of releasing combustion products into the atmosphere directly from the outlet opening 6 of the manifold 3. The exhaust device 5 is located outside the engine housing 1 and is mounted with the possibility of influencing the flow of combustion products directed into the atmosphere from the outlet opening 6 of the exhaust manifold 3.

The outlet device 5 can be made in the form of a rotating disk with a sector-shaped protrusion (not shown in the drawings), having a flat control surface, and the open end of the outlet manifold 3 is located with a gap relative to the control plane of the sector-shaped protrusion.

The outlet device 5 may have a rotating cylindrical control surface 7, and the open end of the outlet manifold 3 is located with a gap relative to said surface 7.

The exhaust device 5 may comprise combustion product flow dividers 8 arranged to act on the flow before the exhaust device creates resistance to the movement of combustion products from the exhaust opening 6 of the manifold 3. The dividers 8 may be in the form of projections of various shapes and arranged at a predetermined distance from one another to allow combustion products to pass between them without significantly resisting their movement. The projections may have aerodynamic surfaces and be designed, for example, in the form of blades that deflect the flow or create useful work transmitted to the engine shaft 4. The dividers 8 may be in the form of circular surfaces, for example, shaped, in which openings for the passage of gases may be made.

The axis of rotation of device 5 can be located in any angular position relative to the axis of rotation of shaft 4.

In this case, the communication of the exhaust channel of cylinder 2 with the exhaust manifold 3 at the place of their connection is made tangential with the possibility of swirling the combustion products in the exhaust manifold 3, in its transverse plane.

The free end of the collector 3 in the area of its outlet opening 6 can be secured to the engine body 1 using a compact bracket (not shown in the drawings) in order to reduce vibrations of the end of the collector 3 relative to the device 5 during engine operation.

The engine described operates as follows. At the end of the combustion product expansion, they begin to freely exit cylinder 2 through the exhaust port and exhaust channel into exhaust manifold 3. After passing through manifold 3, the combustion products are released through outlet 6 directly into the atmosphere. Thus, at least during the free-flowing process, the combustion products flow out of cylinder 2 without any external influence. This accelerates the release of combustion products from cylinder 2 and reduces the amount of residual gases.

The axis, relative to which the spiral of the collector 3 is twisted, can be located in any angular position relative to the axis of rotation of the shaft 4.

Upon completion of free exhaust, the purge ports open, and the process of filling the cylinder 2 cavity with a fresh charge begins. Part of the fresh charge may flow into the exhaust channel and manifold 3 through the exhaust port. Furthermore, during the engine piston's stroke from its bottom dead center, part of the fresh charge is also forced out of the cylinder 2 cavity through the exhaust port. To return the fresh charge back to the cylinder 2 cavity through the exhaust port, at a predetermined moment, coordinated with the piston position in cylinder 2, the gas pressure in manifold 3 is increased by closing the outlet opening 6 of manifold 3 with the control surface 7 of device 5. To implement this phenomenon, it is necessary to ensure the required length and cross-sectional area of exhaust manifold 3. In this case, device 5 is made without a housing and is located in an open space outside the engine housing 1. To reduce exhaust noise and lower the heat flux concentration (when using the engine in military aircraft), the combustion product flow is passed through rotating diffusers 8 on device 5, which do not create significant flow resistance. The diffusers 8 are located on the non-control surface of device 5.

Thus, the use of the described technical solution allows for a reduction in specific fuel consumption while ensuring minimum engine weight, acceptable compactness, and minimal resistance to the movement of combustion products released from the cylinder.

Claims (4)

1. A two-stroke engine with a caseless exhaust device, comprising a housing with a cylinder having purge ports and at least one exhaust port communicated with the atmosphere by means of an exhaust channel of the cylinder and an exhaust manifold, as well as an exhaust device connected to the engine shaft, made with the possibility of creating at least resistance to the movement of combustion products leaving the exhaust manifold during a part of the working process of the engine, characterized in that one end of the manifold is communicated with the exhaust channel, and its other end is made open with the possibility of releasing combustion products into the atmosphere directly from the outlet opening of the manifold, the exhaust device is located outside the engine housing and is installed with the possibility of influencing the flow of combustion products directed into the atmosphere from the outlet opening of the exhaust manifold. 2. An engine according to claim 1, characterized in that the exhaust device is made in the form of a rotating disk with a sector-shaped protrusion having a flat control surface, and the open end of the exhaust manifold is located with a gap relative to the control plane of the sector-shaped protrusion. 3. An engine according to claim 1, characterized in that the exhaust device has a rotating cylindrical control surface, and the open end of the exhaust manifold is located with a gap relative to the cylindrical control surface. 4. An engine according to claim 1, characterized in that the exhaust device contains combustion product flow dividers located with the possibility of influencing the flow before the exhaust device creates resistance to the movement of combustion products from the outlet opening of the manifold.