Method for controlling a two-stroke internal combustion engine

Abstract

The invention relates to engine design. A method for controlling a two-stroke internal combustion engine is claimed in which an air / fuel mixture is homogenized and, upon closure of intake and exhaust ports of a working cylinder, is supplied in a gaseous state to a combustion chamber. The method discloses a process of supplying water or a mixture of water and other fluids when the engine is operating in a steady state. Upon a decrease in engine power, the supply of water or a mixture of water and other fluids is cut off, and the supply of air-fuel mixture is restored upon maximum pressure being reached in the combustion chamber during the stroke in which air / fuel mixture is supplied thereto, when the engine crankshaft crank angle is in a range of from +5 to +30 degrees after maximum pressure in the combustion chamber. Water or a mixture of water and other fluids is then supplied in an amount that makes it possible to maintain a set temperature of the engine combustion chamber in real time. The technical result is that of improving engine operating stability, increasing engine power while at the same time reducing fuel consumption and the toxicity of exhaust gases and increasing engine lifespan.

Description

[0001] Method of controlling a two-stroke internal combustion engine

[0002] The invention relates to engine building and can be used in the production and operation of engines for vehicles.

[0003] A method for controlling an internal combustion engine, protected by Russian patent No. 2707012, is known, in which a fuel-air mixture (FAM) is injected into the combustion chamber from a compressor cylinder equipped with one or more fuel supply devices. The compressor cylinder piston stroke is set with an advance or lag relative to the stroke of the working cylinder piston; in the range of the working piston stroke from bottom dead center (BDC) to top dead center (TDC), a fuel-air mixture is supplied to the combustion chamber, and in the range of the working piston stroke from TDC to BDC, water is supplied to the combustion chamber. The fuel-air mixture is prepared and homogenized in the compressor cylinder at an excess air ratio of X < 0.5, and in the combustion chamber, near the spark plug electrode, a fuel-air mixture is prepared with an excess air ratio of 0.6 < X < 2.0, using air coming from the working cylinder for this purpose.Water is introduced into the combustion chamber, bypassing the compressor cylinder, directly into the combustion chamber or into an annular channel located around the combustion chamber and connected to it.

[0004] The known method ensures safe and stable engine operation, since the preparation of the fuel-air mixture in the compressor cylinder eliminates the possibility of an explosion—an over-enriched fuel-air mixture with an excess air ratio of X < 0.5 does not burn. The fuel-air mixture, prepared near the spark plug, with an excess air ratio of 0.6 < 2.0, easily ignites and burns quickly in the combustion chamber. However, the proposed method does not specify the time, quantity, and temperature at which water is introduced into the combustion chamber. Failure to monitor the engine temperature in the combustion chamber in real time can lead to engine overheating and failure, or to uneven cooling of the aluminum piston, cast-iron cylinder liner, and cylinder block due to differences in their physical and mechanical properties, which will lead to an increase in the clearance in the friction pair between the piston compression rings and the cylinder walls.Increasing the clearance will result in the working pressure in the cylinder being released through the enlarged one.

[0005] 1

[0006] SUBSTITUTE SHEET (RULE 26) clearance in the friction pair of the ring-cylinder wall in the sub-piston space, crankcase and engine sump, which will lead to a reduction in the service life of the oil and its characteristics, an increase in the pressure of crankcase gases increasing the ingress of oil from the sump into the working cylinder, a decrease in engine power, an increase in the toxicity of exhaust gases and a reduction in the service life of the engine.

[0007] The A.N. Sergeev cycle of internal combustion engine control and the engine for its implementation are known, protected by Russian patent No. 2792487, which presents several methods.

[0008] A method of controlling a two-stroke internal combustion engine wherein the fuel-air mixture (FAM) is homogenized at an excess air ratio of X < 0.5. After closing the scavenge and exhaust ports of the working cylinder, the FAM is fed in a gaseous state into the prechamber and combustion chamber at a pressure in the combustion chamber greater than atmospheric, wherein the FAM is depleted in the combustion chamber to an excess air ratio of 0.6 < X < 2.0, using for this purpose air coming from the working cylinder, and providing different FA qualities in the prechamber, combustion chamber and working cylinder. After which spark ignition of the FAM is performed. The ignition advance angle is set in the range of 0°...+20° near TDC depending on the engine crankshaft speed with full filling of the working cylinder with atmospheric air in all engine operating modes at a compression ratio in the combustion chamber of e = 14...20.The upper annular channel around the combustion chamber is used as a pre-chamber, and the fuel mixture is ignited simultaneously by several spark plugs, the electrodes of which are located in the upper annular channel.

[0009] A method of controlling a two-stroke internal combustion engine in which the fuel-air mixture is homogenized and, after the scavenge and exhaust ports of the working cylinder are closed, the fuel-air mixture is injected into the combustion chamber in a gaseous state and spark ignition occurs. At steady state, the fuel-air mixture is stopped, and during the working piston stroke from top dead center (TDC) to bottom dead center (BDC), after the working cylinder crankshaft rotation angle reaches 0...20° after TDC, water or a mixture of water and other liquids is injected directly into the combustion chamber. When engine power decreases, the water or mixture of water and other liquids is stopped and the fuel supply is resumed.

[0010] Known methods in the A.N. Sergeev cycle allow saving fuel by supplying water to the combustion chamber after reaching the angle

[0011] 2

[0012] SUBSTITUTE SHEET (RULE 26) crankshaft rotation angle of the working cylinder 0...20° after TDC, and also improve stability, power, and efficiency. However, known methods do not specify the amount of water required for different engine operating modes. Calculating the amount of water required is impossible due to the lack of real-time engine temperature monitoring. Lack of real-time combustion chamber temperature monitoring can lead to engine overheating and failure, or to different dimensional changes in the aluminum piston, cast iron liner, and cylinder block due to their different physical and mechanical properties when the engine temperature drops below the set point. This will reduce engine performance, reduce its service life, and increase exhaust emissions.

[0013] The technical result of the method for controlling a two-stroke internal combustion engine is an increase in the stability of the engine operation, an increase in its power while reducing fuel consumption, a decrease in the toxicity of exhaust gases and an increase in the service life of the engine.

[0014] To achieve a technical result, a method for controlling a two-stroke internal combustion engine is proposed. This method involves homogenizing the fuel-air mixture and, after closing the scavenge and exhaust ports of the working cylinder, feeding it in a gaseous state into the combustion chamber. The ignition advance angle is set within the range of 0 to +20 degrees around TDC, depending on the engine crankshaft speed. Upon reaching maximum compression pressure, when the piston is at TDC, spark ignition occurs. During steady-state engine operation, the fuel-air mixture supply is stopped in the working piston stroke range from TDC to BDC. After the working cylinder crankshaft rotation angle reaches 0 to 20 degrees after TDC, water, or a mixture of water and other liquids, is fed into the combustion chamber. As engine power decreases, the supply of water, or a mixture of water and other liquids, is stopped and the fuel-air mixture supply is resumed.

[0015] Unlike the prototype, when the maximum pressure in the combustion chamber is reached, in the stroke with the supply of fuel mixture into the combustion chamber, in the range of the engine crankshaft rotation angle of +5... +30 degrees after reaching the maximum pressure in the combustion chamber, water or a mixture of water with other liquids is supplied in an amount ensuring the maintenance of the specified temperature of the engine combustion chamber in real time.

[0016] SUBSTITUTE SHEET (RULE 26) The proposed method ensures the intended engine performance by maintaining a preset engine operating temperature through real-time temperature measurement and the supply of water or a mixture of water and other fluids in the required quantity to maintain the engine's operating temperature. If the amount of water or a mixture of water and other fluids in the fuel-air mixture (FA) supply cycle is insufficient to maintain the operating temperature, the FA supply is stopped until the temperature drops to the preset engine temperature. Engine power is increased by the proposed method by supplying water in the same stroke as the FA supply to the combustion chamber, within the crankshaft rotation range of +5...At +30°C after reaching maximum combustion chamber pressure, when the piston is near TDC, water, or a mixture of water and other fluids, is injected in an amount sufficient to maintain the set combustion chamber temperature in real time. Injecting water into the combustion chamber, at a crankshaft rotation angle of +5°C to +30°C after reaching maximum combustion chamber pressure, creates additional pressure on the working cylinder piston during the fuel-air mixture injection stroke after the cessation of flaming (visible) combustion of the fuel-air mixture. This pressure is generated by the steam pressure after the rapid evaporation of water (the steam stroke) in the combustion chamber. This results in increased engine power and a lower combustion chamber temperature, reduced fuel consumption, reduced exhaust gas toxicity, and improved engine efficiency.Supplying water to the combustion chamber after turning the engine crankshaft more than +30 degrees after reaching the maximum pressure in the combustion chamber does not contribute to an increase in pressure, due to the fact that when the piston moves, the above-piston space (the volume of the combustion chamber) increases and the increase in pressure will be compensated by an increase in the volume of the combustion chamber.

[0017] The proposed method for controlling a two-stroke internal combustion engine is illustrated by graphs, Fig. 1, which shows a graph of engine operation in a cycle with a working stroke of supplying fuel mixture and water into the combustion chamber after the end of visible combustion of the fuel mixture in the combustion chamber, Fig. 2 is a graph of the water supply cycle without supplying fuel mixture into the combustion chamber.

[0018] The proposed method works as follows. The fuel-air mixture (FAM) is homogenized and after the scavenging and exhaust ports of the working cylinder are closed, the FAM is fed into

[0019] 4

[0020] SUBSTITUTE SHEET (RULE 26) gaseous state into the combustion chamber. The ignition advance angle is set in the range of 0 ... +20 degrees (Fig. 1) near TDC depending on the engine crankshaft speed. Upon reaching the maximum compression pressure 1, when the piston is at TDC, spark ignition 2 is performed. Upon reaching the maximum pressure in the combustion chamber 3, in the stroke with the supply of fuel and mixture mixture to the combustion chamber, in the range of the engine crankshaft rotation angle of +5 ... +30 degrees after reaching the maximum pressure in the combustion chamber, when the piston is near TDC, water, or a mixture of water with other liquids 4, is supplied. Water, or a mixture of water with other liquids is supplied in an amount ensuring that the set temperature of the engine combustion chamber is maintained in real time (Fig. 1). At steady-state engine operation, the supply of fuel and mixture mixture is stopped in the range of the working piston stroke from TDC to BDC.Once the crankshaft rotation angle of the working cylinder reaches 0...20 degrees after TDC, water or a mixture of water and other liquids 2 (Fig. 2) is fed into the combustion chamber. When engine power decreases, the supply of water or a mixture of water and other liquids is stopped and the fuel-air mixture supply is resumed.

[0021] Thus, the proposed method for controlling a two-stroke internal combustion engine achieves the technical goal of improving engine stability, increasing its power while reducing fuel consumption, reducing exhaust emissions, and extending the engine's service life. The device can be manufactured using known technologies, components, equipment, and materials. Consequently, the proposed device has industrial applicability.

[0022] SUBSTITUTE SHEET (RULE 26)

Claims

Invention formula A method for controlling a two-stroke internal combustion engine, in which the fuel-air mixture (FAM) is homogenized and, after the purge and exhaust ports of the working cylinder are closed, the FAM is supplied in a gaseous state to the combustion chamber, and the ignition advance angle is set in the range of 0...+20 degrees near TDC depending on the engine crankshaft speed, upon reaching the maximum compression pressure, when the piston is at TDC, and spark ignition is performed, while in the steady-state operating mode of the engine, the FA supply is stopped in the range of the working piston stroke from TDC to BDC, after reaching the crankshaft rotation angle of the working cylinder of 0...20 degrees after TDC, water or a mixture of water with other liquids is supplied to the combustion chamber, and when the engine power decreases, the supply of water or a mixture of water with other liquids is stopped and the supply of fuel and mixture mixture is resumed, characterized in that when the maximum pressure in the combustion chamber is reached, in the stroke with the supply of fuel and mixture mixture to the combustion chamber, in the range of the angle of rotation of the engine crankshaft of +5 ... +30 degrees after reaching the maximum pressure in the combustion chamber, when the piston is in the area of ​​TDC, water or a mixture of water with other liquids is supplied in an amount ensuring the maintenance of the specified temperature of the engine combustion chamber in real time. SUBSTITUTE SHEET (RULE 26)

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