RU2558667C1 - Mode of operation of engine running on gas fuel - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: during operation of the engine with a gas nozzle combined with a spark plug at the suction stroke air is supplied through the open inlet valve into the engine cylinder and the inlet valve is closed after quarter turn rotation of the engine shaft of from the initial position at which the piston is located in the cylinder in top "dead point". During the movement of the piston to the lower "dead point" at the closed inlet valve into the engine cylinder through the nozzle the combustible gas is supplied which is kept supplied into the engine cylinder at the compression stroke during the motion of the piston from the lower "dead point" to the upper "dead point". The supply of combustible gas into the engine cylinder is stopped before turn of the engine shaft to the angle at which the decreasing chamber volume in the engine cylinder becomes equal to the chamber volume in the engine cylinder at the moment of closing of the inlet valve. At further motion of the piston from the lower "dead point" to the upper "dead point" after interruption of supply of combustible gas into the engine cylinder the created air-gas mix is compressed and then ignited by the spark plug.

EFFECT: higher efficiency of engine operation.

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Description

The invention relates to internal combustion engines. It applies to a diesel engine converted to a gas engine.

Patent No. 767380, F02B 69/04, issued in the Russian Federation, shows a diesel-gas four-stroke internal combustion engine, in which, if it is operated on gas fuel, a special pre-chamber is built in to reduce the compression ratio of the air-fuel mixture. However, this requires reworking the engine cylinder head. In patents No. 2097581, 2097582, F02B 43/00, issued in the Russian Federation, using indicator diagrams, methods of operation of an internal combustion engine are described, providing for interruption of the process of suction of the working fluid, which, however, is not consistent with the compression process of the working fluid when converting a diesel engine into gas engine. In patent No. 2342543, F02B 43/00, issued in the Russian Federation, in application No. 2003/0140902, F02B 43/00, published in the United States, a method for performing a duty cycle in a gas-fired internal combustion engine using an injector to supply gas fuel into the combustion chamber under high pressure shortly before the top dead center and means of ignition of the air-fuel mixture. However, with this method of operating a gas fuel engine, it is necessary to excessively increase the fuel injection pressure, which significantly complicates the fuel supply system.

The objective is to ensure efficient operation on gaseous fuel of a diesel engine converted to a gas engine, with simple conversion by installing a gas nozzle in the cylinder head of the engine combined with a spark plug.

The solution to the problem of efficient work on gaseous fuel of a diesel engine converted to a gas engine is ensured by the fact that when working on gaseous fuel of a diesel engine converted to a gas engine by installing a gas nozzle combined with a spark plug, air is let in through the open intake port at the suction stroke valve into the engine cylinder and close the intake valve after turning the engine shaft a quarter of a turn from the initial position at which the piston finds xia in the cylinder at the top dead center. During the movement of the piston to the bottom dead center with the intake valve closed, combustible gas is supplied to the engine cylinder, which continues to be supplied to the engine cylinder at a compression stroke while the piston moves from the bottom dead center to the top dead center. Stop supplying combustible gas to the engine cylinder before turning the engine shaft at an angle at which the decreasing chamber volume in the engine cylinder becomes equal to the chamber volume in the engine cylinder at the time the intake valve is closed. With further movement of the piston from the bottom “dead center” to the top “dead center” after the cessation of the supply of combustible gas to the engine cylinder, the created gas-air mixture is compressed and then ignited by the spark plug. After the piston has a working stroke, exhaust gas is released from the engine cylinder through the exhaust valve.

With this method of operation of the internal combustion engine, gas fuel is injected at low pressure after the intake valve is closed before the actual compression of the air-fuel mixture begins, when the pressure in the engine cylinder does not exceed the pressure at which the intake stroke begins. For this reason, for injecting combustible gas directly into the engine cylinder, it is not necessary to significantly increase the electric drive power of the gas nozzle, since in this case the forces for opening the valve in the gas nozzle do not exceed the forces in the gas nozzles used during external mixture formation. This greatly simplifies the system for injecting combustible gas into the engine cylinder. Moreover, with this method of operation of a gas engine converted from a diesel engine, its effective operation without detonation is ensured.

A method of operating on gaseous fuel from a diesel engine converted to a gas engine by installing a gas nozzle in the cylinder head of the engine combined with a spark plug, shown, for example, in copyright certificate No. 1550201, F02M 57/06, issued in the USSR, in patent No. 8215292, issued in the USA is characterized by the following actions. At the suction stroke, air is let in through the open intake valve into the engine cylinder and the intake valve is closed after the engine shaft is rotated a quarter of a turn from the initial position at which the piston is in the cylinder at the top dead center. After that, during the movement of the piston to the bottom dead center with the intake valve closed, when a significant vacuum of air occurs in the engine cylinder, combustible gas is supplied to the engine cylinder through the nozzle. In the compression stroke, while the piston is moving from the bottom “dead center” to the top “dead center”, flammable gas is continued to be supplied to the engine cylinder, which is facilitated by the significant vacuum in the engine cylinder. Stop supplying combustible gas to the engine cylinder before turning the engine shaft at an angle at which the decreasing chamber volume in the engine cylinder becomes equal to the chamber volume in the engine cylinder at the time the intake valve is closed. That is, they continue to supply combustible gas to the cylinder of the converted engine until a significant vacuum is maintained in the engine cylinder, allowing the supply of combustible gas to the engine cylinder under relatively low pressure. With further movement of the piston from the bottom dead center to the top dead center after the supply of combustible gas to the engine cylinder has ceased, the resulting air-gas mixture, that is, the mixture of air and combustible gas is compressed and then ignited by the spark plug. After the piston has a working stroke, exhaust gas is released from the engine cylinder through the exhaust valve.

The method of operating on gaseous fuel from a diesel engine converted to a gas engine by installing a gas nozzle combined with a spark plug in the cylinder head of the engine is illustrated by a simplified indicator diagram.

In the shown indicator diagram of gaseous fuel operation of a diesel engine converted to a gas engine, the first section “a-b” characterizes the change in the volume of the chamber in the engine cylinder at the inlet stroke of the cylinder with the intake valve open when the piston moves from top dead center (bhm) to the bottom “dead center” (bhh). The air pressure in the cylinder at this stage of the piston movement is slightly less than the pressure in the engine intake pipe. The next section "b-c" characterizes the decrease in air pressure in the engine cylinder after closing the inlet valve with a further movement of the piston to N.M.T. At this stage of the piston movement, when the air pressure in the cylinder decreases, combustible gas is supplied to the cylinder by the nozzle. Section "c-d" characterizes the initial stage of compression of the gas-air mixture, which occurs when the piston moves from NMT to m.t. At this stage, at which the pressure in the cylinder is still low, the flow of combustible gas into the cylinder by the nozzle continues. Section "d-e" characterizes the increase in the pressure of the gas-air mixture in the engine cylinder at the compression stroke after the cessation of supply of combustible gas to the engine cylinder. The “e-f” section characterizes the increase in pressure in the engine cylinder during the combustion of combustible gas after it is ignited by the spark plug. Section "f-g" characterizes the change in pressure in the cylinder of the engine during the working stroke of the piston when it moves from VMT to n.m.t. with closed valves. Section "g-h" characterizes the decrease in the pressure of the exhaust gas in the engine cylinder when the exhaust valve is opened. The "h-k" section characterizes the stage of exhaust gas release from the engine cylinder, which occurs when the piston moves from the engine. to m.t. Section "k-a" characterizes the decrease in pressure in the engine cylinder when the exhaust valve is closed and the intake valve is opened.

In this diesel engine, converted to a gas engine, the geometric compression ratio is maintained, and to reduce the actual compression ratio, the inlet valve is closed when the piston position is significantly higher than the bottom dead center. At this moment, gas fuel injection is started using a gas nozzle combined with a spark plug, which is installed instead of the diesel nozzle in the same hole without changing the design of the cylinder head and cylinder-piston group. Finish supplying combustible gas to the engine cylinder before the actual compression process begins, that is, until the gas-air mixture pressure exceeds atmospheric pressure. Thus, the supply of combustible gas to the engine cylinder occurs at a pressure lower than the pressure in the intake air intake system. This method of supplying gas fuel allows you to supply gas fuel at low gas pressures using simple gas nozzles, which greatly simplifies the injection system. This ensures the efficient operation of the converted gas engine without detonation.

Claims (1)

The method of operation of a gaseous fuel engine converted from a diesel engine to a gas engine by installing a gas nozzle combined with a spark plug, which means that air is sucked in through the open intake valve into the engine cylinder at the suction stroke, and the intake valve is closed after turning the engine shaft to a quarter of a turn from the initial position at which the piston is in the cylinder at the top dead center, while the piston is moving to the bottom dead center with the intake valve closed the panel feeds combustible gas into the engine cylinder through the nozzle, which continues to be supplied to the engine cylinder on a compression stroke while the piston moves from the bottom “dead center” to the top “dead center”, stop supplying combustible gas to the engine cylinder before turning the engine shaft by an angle, in which the decreasing volume of the chamber in the engine cylinder becomes equal to the volume of the chamber in the engine cylinder at the moment of closing the intake valve, with the further movement of the piston from the bottom “dead center” to the top “dead point” after In order to increase the supply of combustible gas to the engine cylinder, the created gas-air mixture is compressed and then ignited with a spark plug, after the piston has made a working stroke, the exhaust gas is discharged from the engine cylinder through the exhaust valve.