RU2063524C1 - Two-stroke internal combustion engine - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: two-stroke engine has twin working cylinder with pistons, common combustion chamber and common spark plug, inlet and outlet ports and pumping cylinder with inlet port and outlet port connected with inlet port by channel. Pistons of working cylinder operate with displacement in shaft turning angle relative to pumping cylinder piston. Working cylinder pistons are connected with driving mechanism to operate with phase shift in working cycle, thus providing first opening and closing of outlet port and then opening of inlet port. Pumping cylinder can be provided with force-operated or self-acting suction valve arranged in cylinder head or suction port made in cylinder above piston on section at the end of piston stroke. EFFECT: enlarged operating capabilities. 6 dwg

Description

 The invention relates to the field of engine building, in particular to two-stroke internal combustion engines with a closed crankcase of the movement mechanism.

 Various designs of two stroke engines are known. The large and main class of two-stroke engines have an open (flowing) crankcase of the movement mechanism (crank mechanism or another) through which the working mixture of gasoline and oil is passed into the cylinders.

 The presence of a flowing crankcase is the main disadvantage of two-stroke engines, since high-quality lubrication of the movement mechanism and piston group is not provided, it turns out that the blowing and filling factor of the cylinder are not efficient due to the large harmful crankcase volume. Two-stroke engines of this type are currently not widely used due to the high smoke emissions and environmental hazards.

 At the same time, designs of two-stroke engines with a closed crankcase of the movement mechanism appeared, in which the latter has an oil bath, like four stroke engines, and the suction and filling cycle of the cylinder is provided using a separate pump cylinder operating in antiphase with the working cylinder.

 As analogues, two-stroke engines having a pump cylinder according to the US patent (1), according to the French patent (2), as well as on the rejected application for the issuance of ed. testimonial. USSR (3).

 As the closest prototype can be considered the design of the engine according to the patent (1).

 The disadvantage of the prototype (1) is the ineffective purge of the working cylinder, which is provided by a baffle screen 37 made on the working piston, as well as the complex design of the working and pump piston. The presence of a baffle screen 37 on the piston allows you to block the path of the fresh mixture from the inlet window 27 to the exhaust window 25.

 However, the effect of this screen is of low efficiency, since a part of the fresh air mixture still slips through the exhaust port 25. The presence of a channel 53 on the piston of the pump cylinder increases the harmful space of the cylinder. The presence of a partition 49 at the channel 53 reduces the fill factor of the cylinder.

 The proposed two-stroke internal combustion engine with a closed crankcase of the movement mechanism, as well as the prototype, contains a working cylinder, in which the inlet window is connected via a channel to the exhaust window of the pump cylinder, and the pistons of the working and pump cylinder work with phase displacement of the operating cycles.

 The aim of the invention is to increase efficiency and liter capacity, as well as simplifying the design. To do this, it is necessary to increase the purge efficiency of the working cylinder and its filling ratio, as well as to simplify the design of the working and pump cylinder.

 This is achieved by the fact that the working cylinder is made double with two pistons and a common combustion chamber, and its pistons are connected to the movement mechanism so that it works with phase displacement of the working cycle, first opening and closing the exhaust window, and then opening the intake window.

 In FIG. 1 6 shows the arrangement of the pistons and the phases of the duty cycle of the engine: in FIG. 1 and 2 phase of the working cycle the end of the working stroke, while in FIG. 1 the arrangement of the pistons, in FIG. 2 current phase by the angle of rotation of the shaft; in FIG. 3 and 4 show the phase of the working cycle the end of the release and the beginning of filling the working cylinder with a fresh mixture; in FIG. 5 and 6 show the phase of the working cycle, the end of compression in the working cylinder and the end of suction in the pump cylinder.

 The engine contains a dual working cylinder 1 m with pistons 2 and 3, with a common combustion chamber 4 and a common spark plug 5, an inlet window 6 and an outlet window 7, as well as a pump cylinder 8 with an inlet window 9 and an outlet window 10 connected via channel 11 with an inlet window 6. The pistons of the working cylinder 2 and 3 operate with a shift in the angle of rotation of the shaft with the piston 12 of the pump cylinder. In this case, the pistons 2 and 3 of the working cylinder 1 are connected to the movement mechanism 13 (crank) so that when the combustion progress is ensured by the angle of rotation of the shaft, first the piston 2 opens and closes the exhaust window 7, and then the piston 3 opens the intake window 6.

 The pump cylinder 8 may have a forced or self-acting (for example, flap) suction valve 14 located in the cylinder head 15, or an inlet window 9 made in the pump cylinder above the piston at its position in the area at the end of the piston stroke (bottom dead center).

 The principle of operation of the engine is as follows. On the phase of the working cycle, the end of the working stroke (Fig. 1 and 2), the piston 2 opens the exhaust window 7 and the burnt mixture (exhaust) is released. At this phase, the compression in the pump cylinder 8 ends, but the exhaust window 6 is still closed by the piston 3. This prevents the fresh mixture from slipping into the window 7. At the working cycle phase, the end of the outlet and the filling cycle of the working cylinder (Figs. 3 and 4), the piston 2 closes the windows 7 and only after that the piston 3 opens the window 6. At this phase, the compression of the fresh mixture in the pump cylinder 8 ends and the mixture is bypassed through the window 10, channel 11 and window 6 into the working cylinder 1 and the latter can be filled with the calculated overpressure, t since window 7 is already closed, i.e. e. it becomes possible to increase the fill factor of cylinder 1 many times and increase its liter capacity.

 In the phase of the working cycle, the end of the compression cycle in the working cylinder and the end of the suction cycle in the pump cylinder (Figs. 5 and 6), the window 10 is closed by the piston 3 and both pistons 2 and 3 are at top dead center. In this case, the piston 12 lowers down and the pump cylinder is filled with fresh mixture either through the suction valve 14 (self-acting or forced) or through the inlet window 9. It is possible that the pump cylinder 8 will be filled first through the valve 14, and at the end of the stroke to increase the coefficient filling through the window 9.

 After applying voltage to the spark plug, the mixture ignites and a stroke starts (pistons 2 and 3 go down), and piston 12 goes up and compresses the fresh mixture.

 All working phases occur in one revolution of the shaft, which allows for a given liter volume two or more times to increase the power of a two-stroke engine compared to a four-stroke with the same liter volume.

 Compared with the prototype (1), the purge of the working cylinder is improved, the filling coefficient and the liter capacity are increased. In addition, the design of the working and pump cylinder is simplified. YYY2 YYY4

Claims (1)

 A two-stroke internal combustion engine with a closed crankcase of the movement mechanism, comprising a crank mechanism connected to the pistons of the working and pump cylinders in which the inlet and outlet windows are made, the working cylinder being made double, with two pistons and a common combustion chamber, with each piston made with its own crank, characterized in that the crank of the piston of the working cylinder with the exhaust window is installed with a deviation in the angle of rotation of the shaft from the crank of the piston of the working cylinder with the inlet window m in the rotational direction, with the opening and closing timing of the exhaust of the working cylinder of the window relative to the inlet port.

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