Internal combustion engine having scavenging control valve

Abstract

The invention aims to provide an internal combustion engine equipped with a scavenging control valve, in which blow-by of combustion gas from the upper annular space above the top piston ring to the scavenging ports is prevented by which reduction in engine performance due to deposition of combustion gas residuum to the scavenge openings and occurrence of piston ring sticking due to deposition of combustion gas residuum to the piston rings can be prevented, and further the amount of working oil to drive the scavenging control valve can be reduced resulting in decreased energy loss for pressurizing the working oil. An annular-shaped scavenging control valve is fitted-in to a fitting face formed on the inner side of the cylinder liner movably in circumferential direction of the cylinder liner for opening and closing said scavenging ports in order to allow scavenge air to be supplied into the cylinder or interrupted, said scavenging control valve has a plurality of scavenge openings arranged along circumferential direction and in a plurality of stages in axial direction thereof so that the scavenge openings are brought into communication or discommunication with the scavenging ports of the cylinder liner by moving the scavenging control valve in circumferential direction thereof, and the scavenge openings of each stage has a height L1 which is smaller than a inside distance L2 between a top piston ring and a bottom piston ring equipped to a piston of the engine as shown in.

Description

technical field [0001] The invention is applied to a large-scale two-stroke cycle engine, which has a plurality of air exchange ports arranged along the circumference of the cylinder liner at the lower part of the cylinder liner for introducing scavenging air into the cylinder, and the invention relates to a machine equipped with a scavenging air The internal combustion engine of the control valve device, the scavenging control valve device controls the opening and closing of the air exchange port so that when the scavenging control valve is rotated to the position where the scavenging air port of the scavenging control valve communicates with the air exchange port of the cylinder liner, the scavenging air is Provided to the cylinder, and when the scavenging control valve is rotated to the position where the scavenging port of the scavenging control valve closes the gas exchange port of the cylinder liner, the scavenging supply is interrupted. Background technique [0002] U...

AI Technical Summary

Problems solved by technology

[0009] Thus, when the piston 103 moves downward and the piston top ring starts to open the scavenging port 4, the combustion gas flows from the upper annular space 103a on the piston top ring and from the scavenging port 4 to the piston skirt, as Figure 10 As shown by the middle arrow T, it will lead to the reduction of engine performance and the occurrence of piston ring holding phenomenon due to the deposition of combustion gas residue on the piston ring

[0010] In addition, the scavenging control valve 1 is moved in the circumferential direction by the scavenging control valve driving device. The driving device relies on a solenoid valve to switch between supplying and discharging working oil, so that the scavenging port of the scavenging control valve starts to contact with the cylinder liner. There are problems in that the amount of working oil for driving the scavenging control valve drive unit is considerably large and the energy loss for pressurizing the working oil is increased

However, this document does not teach multiple air exchange ports arranged in multiple stages circumferentially and axially

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