RU2835711C1 - Two-stroke internal combustion engine - Google Patents

Abstract

FIELD: engines.

SUBSTANCE: invention relates to engine building, in particular, to two-stroke internal combustion engines (ICE). Disclosed is a two-stroke ICE comprising a cylinder with a combustion chamber, a piston, ignition plug 3, fuel injector 2, air injector 1 and an outlet valve with electric drive 4 and pneumatic drive 5, which are installed in the cylinder head of the ICE and electrically connected to the engine control unit. Engine crankcase is connected to air nozzle 1 and exhaust valve pneumatic drive 5 by means of receiver tube 7, on which bypass valve 6 and electrically controlled bypass valve 8 are installed, which control air pressure in receiver tube 7. Electrically controlled bypass valve 8 is electrically connected to engine control unit. Air filter 10 with valve 13 is installed on the crankcase. To increase the air compression pressure in the ICE crankcase, the lower part of the piston has outlets on the piston, which fill the space between the crankshaft cheeks at the lower dead point.

EFFECT: increased efficiency and improved performance of ICE.

1 cl, 3 dwg

Description

The invention relates to the field of internal combustion engines, namely to methods of supplying fuel and designs of gas distribution systems for piston two-stroke engines.

The ignition of the fuel-air mixture in a two-stroke internal combustion engine occurs during the working stroke of the piston. When the piston descends to the bottom dead center, the exhaust port opens first and the exhaust gases begin to leave the cylinder, and then, as the piston moves further to the bottom dead center, the inlet port opens and the fuel-air mixture begins to flow from under the piston space into the working cavity of the cylinder, displacing the exhaust gases. After passing the bottom dead center and the piston begins to rise upward, the inlet port closes first, then the outlet port, and compression of the fuel-air mixture begins, which ends with ignition at the top dead center. The processes of cleaning exhaust gases and filling the cylinder in a two-stroke engine are combined and are carried out in a short time when the piston is near the bottom dead center.

A method for feeding a piston internal combustion engine is known (Patent No. 2725310), which includes removing exhaust gases with high-pressure compressed air in a short period of time before the piston passes the top dead center, as well as forming a working mixture with high-pressure compressed air supplied in a short period of time after the piston passes the top dead center. To implement the said method for feeding a piston internal combustion engine, an air supply device is used, containing a two-chamber receiver, with chambers of different volumes, with controlled inlet valves for the combustion chamber, and a compressor with inlet and outlet valves. The compressed air receiver is made for high pressure (about 2 MPa). The small section is intended for active purging of the combustion chamber, and the main section is for forming the working mixture. The volume of the main section of the receiver is at least equal to the volume of the combustion chamber.

A two-stroke engine is known (patent CN115324728) consisting of a compression cylinder, a displacement mechanism, a lubricating oil injection device and an oil-gas separator. The compression cylinder consists of a cylinder body and a scavenging channel connected to the cylinder body, and the cylinder body is provided with air inlet and outlet openings. The scavenging air duct consists of first and second ports that communicate, and the first port communicates with the air intake. The displacement mechanism is movably located in the cylinder body. When the displacement mechanism is located in the first position, the outlet opening and the second opening are shielded. When the displacement mechanism is located in the second position, the outlet opening communicates with the first opening. The lubricating oil injection device is used to inject lubricating oil into the displacement mechanism. An oil-gas separator is located in the scavenging channel and is used to separate the lubricating oil and gas passing through the first port.

A two-stroke internal combustion engine (patent No. 2349769) is known, taken as a prototype, in which the combustion chamber is filled with compressed air and fuel during operation, or the air-fuel mixture is formed under pressure outside the combustion chamber. This scheme allows not only to burn fuel more completely, but also to automatically change various specified parameters during engine operation in order to obtain the highest possible efficiency, as well as to use various types of fuel and their mixtures without changing the design of the internal combustion engine. The engine operates with the highest possible efficiency at any load on the engine shaft, since in all operating modes the required number of working cylinders, the concentration of fuel in the mixture and the selection of pressure in the combustion chamber are automatically selected. This engine can be used underwater, in rarefied environments. Any fuel, excluding solid fuel, can be used for the operation of this engine. It is possible to use oxygen or an oxygen-fuel mixture instead of air or an air-fuel mixture.

The main disadvantage of existing two-stroke internal combustion engines is their low efficiency compared to four-stroke engines, low environmental friendliness due to the combustion of oil added to the fuel. Low efficiency is associated with the design of the valve timing system. The supply of the fuel-air mixture and the release of combustion products occurs through windows in the cylinder that open when the piston moves down at the bottom dead center. This leads to the simultaneous flow of the processes of filling the cylinder and cleaning it from combustion products. As a result, negative phenomena that reduce the efficiency of operation: mixing of the fuel-air mixture with exhaust gases, partial removal of the fuel-air mixture together with the exhaust gases, energy costs for compression of part of the remaining exhaust gases.

The technical problem that the invention is aimed at solving is the creation of a design for a two-stroke internal combustion engine that will significantly increase its functionality.

The technical result obtained with the practical use of the proposed invention is the isolation of the processes of exhaust gas removal and fuel-air mixture intake and compression of the fuel-air mixture; an increase in operating efficiency to the level of four-stroke engines; the possibility of forcing by increasing the amount of fuel burned per stroke by intake of the required amount of air; an increase in efficiency when using a compression ratio corrector; improved environmental friendliness due to the supply of clean fuel without oil admixture to the combustion chamber.

The technical problem is solved due to the fact that in a two-stroke internal combustion engine containing a cylinder with a combustion chamber, a piston; a spark plug, a fuel injector, an air injector and an exhaust valve with an electric drive, installed in the cylinder head of the engine and electrically connected to the engine control unit, according to the claimed technical solution, the exhaust valve is made with an electric drive and a pneumatic drive, the engine crankcase with an air injector and a pneumatic drive of the exhaust valve is connected by means of a receiver tube, a bypass valve and an electrically controlled bypass valve are installed on the receiver tube, the electrically controlled bypass valve is electrically connected to the engine control unit, an air filter with a valve is installed on the crankcase, and outlets are made on the piston.

The proposed design of a two-stroke internal combustion engine is illustrated by the drawings: Fig. 1 - drawing of the engine (piston movement downwards), Fig. 2 - drawing of the engine (piston movement upwards), Fig. 3 - location of the piston at the bottom dead center.

The following notations are introduced:

1 - air injector, 2 - fuel injector, 3 - spark plug, 4 - electric valve actuator, 5 - pneumatic actuator of the exhaust valve, 6 - bypass valve, 7 - receiver tube, 8 - electrically controlled bypass valve, 9 - compressed air, 10 - air filter, 11 - exhaust gas removal, 12 - air intake into the crankcase, 13 - valve.

Fuel injector 2, air injector 1, spark plug 3 and electrically operated exhaust valve 4 are installed in the engine cylinder head and are electrically connected to the engine control unit.

Receiver tube 7 connects the engine crankcase, where air compression occurs, with air nozzle 1 and pneumatic actuator of exhaust valve 5.

The receiver tube 7 serves to accumulate compressed air for subsequent air injection and use to control the exhaust valve.

The bypass valve 6, installed on the receiver tube 7, serves to regulate the pressure in it; the pressure in the receiver tube 7 depends on the force of pressing the needle of the electrically controlled bypass valve 8 to the seat; the force is regulated by changing the magnetic field of the solenoid acting on the needle, and is controlled by the engine control unit.

Air enters the crankcase through air filter 10; valve 13 prevents air from escaping during compression.

A two-stroke internal combustion engine works as follows.

During operation, all processes are isolated: the working stroke, the supply of the fuel-air mixture, the removal of exhaust gases. During the first stroke, the fuel-air mixture is ignited, the working stroke of the piston is simultaneously with the compression of air under the piston. During the second stroke, the exhaust gases are ejected and the under-piston space is simultaneously filled with air for further compression, the stroke ends with the injection of compressed air and fuel by injectors into the combustion chamber.

During the working stroke, the piston compresses air in the crankcase (Fig. 1). Compressed air 9 enters under pressure through the bypass valve 6 into the receiver tube 7, which is connected to the air nozzle 1 and the pneumatic drive of the exhaust valve 5. The pressure in the receiver tube 7 is regulated by an electrically controlled bypass valve (compression ratio corrector) 8. The electrically controlled bypass valve 8 can be made in the form of a needle pressed by a magnetic field, and accordingly, the pressure in the receiver tube 7 is regulated by the pressing force.

Air is stored under pressure in receiver tube 7 in the volume required for the next injection stroke and control of the pneumatic drive of exhaust valve 5.

After passing the bottom dead center, the pneumatic drive of the exhaust valve 5 opens and is held open until the piston reaches the top dead center to remove exhaust gases 11 (Fig. 2).

At the same time, the sub-piston space and crankcase are filled with a new portion of air 12 through the air filter 10.

When the piston reaches the top dead center, the electric drive 4 and the pneumatic drive of the exhaust valve 5 close and fuel and air are injected into the combustion chamber using the fuel injector 2 and the air injector 1, followed by ignition of the mixture by the spark plug 3.

The diameter of the receiver tube 7 is selected to store the volume of air required for 2 strokes of engine operation.

To achieve the required pressure, it is necessary to use a piston of a special shape to compress the air in the crankcase to a pressure of 10-12 atm, so that the ratio of the volume of the crankcase and cylinder at the top dead center and the volume of the crankcase and cylinder at the bottom dead center is not less than 1 to 15 (Fig. 3).

In a conventional internal combustion engine, a lot of air remains in the crankcase between the crankshaft cheeks at the bottom dead center, which prevents the maximum crankcase pressure of 12-15 atm from being reached. In order to reduce the residual air volume between the cheeks, outlets are made on the piston that fill the space between the cheeks at the bottom dead center (Fig. 3).

An approximate calculation of the volume of air compressed by the piston and the air remaining in the crankcase and crankshaft space shows that the maximum calculated pressure that can be created without outlets on the piston is 8-9 atm (in reality 5-6 atm), and using outlets on the piston, which at the bottom dead center fill about half of the space between the cheeks, the calculated pressure is up to 18 atm, and in reality 13-15 atm, which is enough for the operation of an internal combustion engine.

The claimed design allows to transfer the process of air compression to the under-piston space and crankcase and to combine the compression process with the working stroke. The introduction of a compression ratio corrector into the design, implemented using an electrically controlled bypass valve 8, allows to change the volume of compressed air (by changing the pressure in the receiver tube 7) depending on the volume of fuel burned in the next stroke (only the amount of air that is necessary in the next stroke is compressed, and excess air is discharged through the electrically controlled bypass valve 8, which allows not to waste the energy of the working stroke on compressing excess air). Changing the design of the crankshaft and piston allows to create maximum pressure at the bottom dead center in order to minimize the residual volume of air in the crankcase.

A two-stroke internal combustion engine was manufactured according to the claimed design, which demonstrated the implementation of the technical result during operation.

Claims (1)

A two-stroke internal combustion engine comprising a cylinder with a combustion chamber, a piston; a spark plug, a fuel injector, an air injector and an electrically driven exhaust valve installed in the engine cylinder head and electrically connected to the engine control unit, characterized in that the exhaust valve is made with an electric drive and a pneumatic drive, the engine crankcase with the air injector and the pneumatic drive of the exhaust valve is connected by means of a receiver tube, a bypass valve and an electrically controlled bypass valve are installed on the receiver tube, which serve to regulate the pressure in the receiver tube, the electrically controlled bypass valve is electrically connected to the engine control unit, an air filter with a valve preventing the release of compressed air from the engine crankcase is installed on the crankcase, in order to increase the pressure of the air compressed by the piston in the engine crankcase, outlets are made on the piston, filling the space between the crankshaft cheeks at the bottom dead center.