RU2791583C1 - Star-shaped two-stroke internal combustion engine - Google Patents

Abstract

FIELD: engine building.

SUBSTANCE: two-stroke star-shaped multi-cylinder internal combustion engine consists of a crankcase 6, a crankshaft 7 with main 2 and trailing 5 connecting rods, cylinders 1 and pistons 4. The under-piston cavities of each cylinder 1 are separated from the cavity of the common crankcase by sliding valves 3 driven by connecting rods 2, 5, having a variable reduced cross section corresponding to the position of the connecting rods 2, 5 in the area of connection with the drive holes in said sliding valves 3. The engine is made with the possibility of suction from the common crankcase through the window of the fuel-air mixture or air opened by the sliding valve 3 into the under-piston cavity, forcing the fuel-air mixture in the under-piston cavity, and also purging the working cavity of the cylinder with the fuel-air mixture or air from the under-piston cavity through the purge channels when the piston 4 opens purge windows.

EFFECT: increase of the engine power.

1 cl, 5 dwg

Description

The invention relates to mechanical engineering, in particular to multi-cylinder two-stroke radial internal combustion engines, and can be used on stationary and transport units such as airboats, hovercraft, light and ultralight aircraft.

Known two-stroke internal combustion engine, made in-line with the arrangement of the cylinders through the dividing wall one above the other; the pistons of the cylinders of the previous row are connected by rods with the pistons of the cylinders of the next row, and the working cylinder is made double with two pistons and a common combustion chamber communicating its two working cavities, which are located on one or both sides of the partition, exhaust and inlet windows are made in the working cylinder, while the latter are connected to a purge source [RF Patent No. 2143077, cl. F 02 B 33/00, Appl. 06/22/98, publ. 12/20/99, Bull. No. 35].

This engine has a complex design, as a result, low reliability and high metal consumption.

Known two-stroke internal combustion engine containing crankcase, cylinder, crankshaft, connecting rod, piston, block head, exhaust valve contained in the block head and connected to the working cavity

cylinder with a bypass opening a combustion chamber, which contains a bypass valve, an inlet valve, an injection chamber connected to the combustion chamber by an inlet opening and a rotor-supercharger of air or a working mixture connected to the injection chamber [see Fig. US patent N 5333582, IPC F 02 B 19/02, publ. 1994].

The disadvantage of the known engine is its massiveness, and the power output per unit mass is small. Bulky crank and gas distribution mechanisms absorb significant energy, lowering the coefficient of performance (COP).

The closest in technical essence is the two-stroke engine VP-760, developed by V.P. Polyakov [V. Gusev, A. Leparsky. "Great motor waiting to work." AeroMaster, Popular quarterly almanac No. 1, 1998, Tomsk, pp. 119-121]. In this engine, the cylinders consist of two parts - delivery and working, the pistons are made in two stages. Star engine. The distribution mechanism is made in the form of a spool mounted on the crankshaft connected by the crank pin to the main connecting rod of one of the cylinders. And the connecting rods of the remaining cylinders are pivotally connected to the main connecting rod. The working part of the cylinder is connected to the receiver by inlet pipes that supply fuel. The mixing chamber is connected to the injection parts of the cylinders by injection channels. The suction of fuel into the discharge part of the cylinder occurs when the spool window is aligned with the inlet to the injection channel. The flow of fuel into the receiver, and from there into the working part of the corresponding cylinder, occurs when the spool groove is aligned with the inlet to the discharge channel and the connecting hole in the body of the mixing chamber.

The main disadvantages of such an engine is that with such a design of the injection system, an injection cylinder of a larger diameter is added to each working cylinder. Thus, the weight of the piston increases, respectively, the inertia forces that affect the balance of the engine increase. The number of piston rings increases and, accordingly, the resistance to piston movement, the scavenging channels are also lengthened, causing resistance to scavenging the cylinders. All this leads to a decrease in liter engine power and manufacturing complexity.

The technical result of the invention is to increase the power, simplify the design and reduce the mass of a two-stroke multi-cylinder radial internal combustion engine through the use of a local injection system for each individual cylinder, in which the purge of the working cavities, the suction and injection of the fuel-air mixture or air in the under-piston cavities alternately occur in cylinders separated from the cavity of the common crankcase by gate-type spools controlled by the main and trailer connecting rods. The illustrations show a five-cylinder engine.

It is known that the most common, lightweight, reliable and simple design of the scavenging system in two-stroke engines is the crank-chamber scavenging. With such a purge, the reverse side of the working piston is used to suck in and pump the purge mixture or air with the addition of oil to lubricate the crankshaft and the cylinder-piston group. But this method of injection is applicable only on single-cylinder and two-cylinder engines with an opposed arrangement of cylinders, a common crank chamber, with pistons moving in opposite directions and simultaneously reaching top dead center (TDC), due to the fact that suction and discharge occur in the crank chamber, not separated from the cylinder cavities. In other multi-cylinder two-stroke engines, with pistons alternately reaching TDC, using crank-chamber scavenging, each cylinder or pair of opposed cylinders has its own separate crank chamber.

The claimed technical result is achieved due to the fact that in the design of the proposed star-shaped two-stroke engine containing crankcase 6, Fig. 1, crankshaft 7, with one crank, main connecting rod 2, trailer connecting rods 5, pistons 4, and cylinders 1, suction, injection and purging of the fuel-air mixture or air occurs in each cylinder, separated from the crankcase with a common crank chamber by a flat slide spool 3. And the main and trailer connecting rods cross the spools through the drive holes in them. At the same time, the spools move freely in the grooves between the crankcase and the cylinder.

It is known that the connecting rod in the crank mechanism performs simultaneously reciprocating and angular alternating motion. The upper head of the connecting rod moves parallel to the axis of the cylinder, and the lower head rotates along with the crankshaft around its axis. The rod connecting the heads of the connecting rod makes a complex movement in a plane coinciding with the axis of the cylinder and perpendicular to the axis of rotation of the crankshaft.

In the proposed engine design, flat spools intersecting with the rods of the main and trailer connecting rods passing through the drive hole in the spools are in sliding engagement with the rods of the main and trailer connecting rods. Accordingly, with simultaneous plane-parallel movement and a change in the angle of inclination, the main and trailing connecting rods move the spools with their rods. Since the movement of the main and trailer connecting rods is alternating, the spools perform a reciprocating movement synchronized with the movement of the pistons. To implement the process of suction and injection of the fuel-air mixture or air in the under-piston cavity, the spools are made asymmetrical. One side of the spool, relative to the drive hole, has a large length, and when the main and trailer connecting rods are tilted corresponding to the movement of the piston to BDC (discharge), it closes the cylinder cavity from the crankcase cavity. The other side has a shorter length, and when the main and trailer connecting rods are tilted corresponding to the movement of the piston to TDC (suction), it forms a window between the cylinder cavity and the crankcase cavity. And the fuel-air mixture or air enters the crankcase cavity through the inlet port 8, Fig. 3.

The invention is illustrated by drawings that do not cover the entire scope of claims of this technical solution, but are illustrative materials of a particular case of a five-cylinder engine variant:

In FIG. 1 engine in cross section.

In FIG. 2 diagram of engine operation processes.

In FIG. 3 Isometric view of a five-cylinder engine and the location of the intake port.

In FIG. 4 Spool.

In FIG. 5 Connecting rod.

The engine works as follows.

In turn, in each cylinder, when the piston passes the bottom dead center (BDC), the main and trailer connecting rods, changing the angular position to the corresponding compression stroke, with their rod move the spool to the position of an open window between the cylinder and the crankcase common to all cylinders "a" Fig. 2.

Further movement of the piston to TDC creates a vacuum under the piston, and the fuel-air mixture or air is sucked from the crankcase through the window opened by the spool into the under-piston cavity of the cylinder "b", (the movement of the mixture is shown by curved arrows, the movement of the pistons is straight). At this time, in the working cavity of the cylinder, the piston moving to the TDC closes the exhaust and purge windows, the mixture is compressed and ignited from the spark plug "c". When the piston passes TDC, the main and trailer connecting rods, changing the inclination in the opposite direction and occupying a position corresponding to the working cycle, transfer the spool to the position of the closed window “d”, between the cylinder and the crankcase. Further movement of the piston to BDC forces the air-fuel mixture or air into the under-piston cavity of the cylinder between the piston and spool "e". At this time, the piston performs useful work in the working cavity of the cylinder, moving until the outlet window opens in the cylinder, through which the exhaust gases exit. Then, when the purge windows are opened, the compressed fuel-air mixture or air from the under-piston cavity enters the working cavity of the cylinder through the purge channels "g" purge occurs. Having reached the BDC piston, the main and trailing connecting rods, changing the inclination, again transfer the spool to the open window position. The cycle is repeated.

During the operation of the crank mechanism, when the angle of inclination of the rod of the main and trailer connecting rods relative to the spool is changed, the length of the section of their intersection changes depending on the angle of inclination. Since the main and trailing connecting rods move simultaneously with the inclination, the rod has a variable reduction in the section "A" of Fig. 5 corresponding to the position of the main and trailer connecting rods in the mating area. The size of the reduction in the section "A" is equal to the product of the size of the hole in the spool "B" of Fig. 4 and the cosine of the angle of inclination of the main and trailing connecting rods. Thus, the gap in the mating of the rod of the main and trailer connecting rods and the spool is minimized, for the tightness of the under-piston cavity.

A distinctive feature of the prototype in the proposed engine is that for the implementation of the process of suction, injection and purge of the fuel-air mixture or air, the main elements of the engine are used - cylinders, pistons and connecting rods. And only light, easy-to-manufacture spools in the form of plates with a hole are added. Made from lightweight but durable materials such as polyamide, fiberglass, carbon fiber Fig. 4. Such spools have a disproportionately lower mass in comparison with the mass of elements of a metal-intensive and complex injection and gas distribution system of the prototype engine. Accordingly, the mass of the engine is reduced. And the simplicity of the design increases reliability. In the proposed design, the purge channels connecting the under-piston cavity with the cylinder purge windows have a short path compared to the prototype, which means less resistance to the movement of the fuel-air mixture, improved purge and filling of the working cavity of the cylinder and, as a result, an increase in engine power.

An essential technical solution is, which has not been used anywhere before, the use of main and trailer connecting rods with a variable reduced section corresponding to the position in the area of interfacing with drive holes in slide valves separating the under-piston cavity of the cylinder from the crankcase. Possibility of a gate valve, driven by the main and trailer connecting rods, to implement suction from a common crankcase through a window of a fuel-air mixture or air into the under-piston cavity opened by a spool, injection after closing the window with a valve and purging the working cavity of the cylinder with a fuel-air mixture or air. Another advantage of the proposed engine is the possibility of using elements of cylinder-piston groups in it from available, mass-produced two-stroke engines with crank-chamber scavenging.

Claims (1)

Two-stroke star-shaped multi-cylinder internal combustion engine, consisting of a crankcase, crankshaft with main and trailer connecting rods, cylinders and pistons, while the under-piston cavities of each cylinder are separated from the cavity of the common crankcase by gate-type spools driven by connecting rods having a variable reduced section corresponding to the position of the connecting rods at the interface with the drive holes in these spools, the engine is also made with the possibility of suction from the common crankcase through the window of the fuel-air mixture or air into the sub-piston cavity opened by the spool, pumping the fuel-air mixture in the sub-piston cavity, as well as purging the working cavity of the cylinder with fuel - air mixture or air from the under-piston cavity through the purge channels when the purge windows are opened by the piston.

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