Scavenge efficiency can be defined as the ratio of the volume of air in the cylinder at the start of the compression to the volume swept by the piston from the top edge of the ports to the top of the strokes.Īir charge ratio can be defined as the ratio of the air contained in the cylinder at the start of the compression to the swept volume of the piston. In marine engines, the volumetric efficiency generally falls between 0.85-0.95. Volumetric efficiency can be defined as the ratio of the volume of air drawn into the cylinder to the swept volume. Marine engines with smaller cylinders will have higher compression ratio. Compression ratio outside this ratio would either prevent the engine from starting or lead to other problems. The compression ratio can be defined as the value obtained by dividing the total cylinder volume by the clearance volume.Ĭompression ratio is generally between 12 and 18 however, it depends on the design of the engine. The space covered by the clearance volume also forms the combustion chamber. Swept volume is also the product of piston area and stroke.Ĭlearance volume can be defined as the volume that remains in the cylinder when the engine piston is in the top centre position.Ĭlearance volume can also be defined as the difference between the total cylinder volume and the swept volume. Swept volume can be defined as the volume swept by the engine piston during one stroke. In this article, we have enumerated eight important definitions of marine engine terms which are extremely important and which will be used throughout the professional life of a marine engineer. Moreover, there are several engineering terms which an engineer should know like the back of his hand. Needless to say, it is imperative for every marine engineer to know this important machine inside out.Ī Marine engine is a complex machine, which requires years of experience and knowledge for understanding and handling the same. The study of marine engines forms an integral part of marine engineering syllabus. s i z e e n g i n e \mathrm 12 i n 3 and has two identical compartments.If you are a marine engineer or aspiring to be one, then it’s obvious that you would eat, breath, and sleep marine engines.The throttle is what the gas peddle controls. As there is now sufficient oxygen for all that fuel, its combustion releases more energy to drive the engine, which accelerates the vehicle. When the throttle valve is open, the air inside the carburetor increases, increasing both the air and fuel amount in the engine. On the other hand, the valve at the bottom is called the throttle. If the choke is closed, less air flows in which reduces combustion in the engine due to lack of oxygen. The valve at the top is called the chokeĪnd regulates how much air can flow in. When the fuel gets sucked into the engine, we've achieved what we wanted, but how the air-fuel mixture can be adjusted? There are two valves above and below the venturi. The quicker the air's initial movement, the more it's speed increases by, which causes a lower pressure, drawing more fuel into the airflow and engine. To conserve mechanical energy, an increase in the air's speed must be met with a decrease in pressure, and this decrease in pressure is enough to draw fuel from the fuel intake into the airflow. This pipe passes through a venturi, which is connected to the fuel intake.Ī venturi is a slightly narrower area of pipe which causes air to speed up when passing through it. Carburetors can be thought of as a pipe that pumps more air into the engine as you push on the accelerator. Isn’t it incredible that birds and planes can even fly? That's all down to the Bernoulli equation, which is the same principle that carburetors work on.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |