What is meant by scavenging in two stroke engines?
Abstract: The process of simultaneously purging exhaust gas and filling the cylinder with fresh charge for a new cycle is referred to as scavenging. The main scavenging methods are cross scavenging, loop scavenging and uniflow scavenging.
Why is uniflow scavenging better?
Uniflow is the most efficient scavenging system but requires either an opposed piston arrangement or an exhaust valve in the cylinder head. All three systems have the ports angled to swirl the incoming air and direct it in the appropriate path.
What is uniflow scavenging?
Uniflow scavenging is a design in which the fresh intake charge and exhaust gases flow in the same direction. This requires that the intake and exhaust ports be at opposite ends of the cylinder.
How can you increase the efficiency of a 2 stroke engine?
First, an electric turbocharger allows for “variable compression ratio,” whereby the inlet pressure fed into the engine’s cylinders is varied to maximize efficiency. Second, an approach called asymmetrical port timing–opening the intake and exhaust ports at different times–helps improve the efficiency of gas exchange.
What are the three types of scavenging?
The process of admitting air and expelling exhaust gas is known as scavenging. The three main types of scavenging for two stroke engines are cross flow, uniflow and loop flow.
What are the three methods of scavenging explain each?
Three basic systems are in use: the cross flow, the loop and the uniflow. All modern slow-speed marine diesel engines now use the uniflow scavenging system with a cylinder-head exhaust valve. In cross scavenging the incoming air is directed upwards, pushing the exhaust gases before it.
What do you think is the advantage of uniflow scavenging as applied to a super long stroke engine?
Advantages and disadvantages of uniflow scavenging Increase power output. Most efficient of all three methods. Good scavenging at all speed ranges and throttle position. Low fuel consumption compared to other scavenging types.
Is a 2 stroke more efficient?
Compared to four stroke engines, two strokes are lighter, more efficient, have the ability to use lower-grade fuel, and more cost-efficient. Therefore, the lighter engines results in a higher power-to-weight ratio (more power for less weight).