marine diesel engine

Abstract

The present invention provides a marine diesel engine capable of stabilizing combustion in a critical speed range and operating the engine main body under better conditions. It has: an engine main body, which controls the exhaust gas from the combustion chamber by opening and closing the exhaust valve; In the exhaust valve closing timing mode, the timing of closing the exhaust valve in the combustion cycle is delayed as the speed of the engine body increases, and the exhaust valve closing timing mode is when the speed of the engine body passes through the critical speed range. There is an inflection point at which the change rate of the change in the timing of closing the exhaust valve relative to the increase in the rotational speed changes in the critical rotation range and the first range in which the rotational speed is lower than the critical rotational range, and the rate of change on the critical rotational range side from the inflection point The rate of change is smaller than the rate of change on the side of the first range from the inflection point.

Description

technical field [0001] The invention relates to a marine diesel engine. Background technique [0002] The marine diesel engine increases the rotational speed when starting to operate. Since the engine is a rotating machine, there is a critical speed range (Barred Range / barred range, critical speed / critical speed) in which resonance or the like occurs and long-term operation in this speed range is prohibited. Patent Document 1 describes adjusting the angle of injecting fuel and opening the angle of an exhaust valve for exhausting air combusted in a combustion region when the engine speed reaches a critical speed range. Specifically, it is described that the exhaust angle in the critical speed range is made smaller than the exhaust angle in a region lower than the critical speed range. [0003] prior art literature [0004] patent documents [0005] Patent Document 1: Japanese Utility Model Registration No. 3174346 [0006] In addition, in marine diesel engines, in order ...

AI Technical Summary

Problems solved by technology

In this way, when the control to increase the rotational speed of the engine is executed, the balance of fuel and air in the engine is disrupted, the combustion of the fuel becomes insufficient, and there is a possibility that the speed of increase of the rotational speed may decrease or black smoke may be generated.

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