A two - stroke engine has ports in which of the following?

Question

Question

This question was previously asked in

RRB ALP Mechanic Diesel 21 Jan 2019 Official Paper (Shift 1)

Answer 1

Explanation:

A two-stroke engine has three ports on the cylinder walls:

Inlet port:

Exhaust port:

Transfer port:

The transfer port is located inside the engine.
It is used for transferring the charge from the crankcase to the cylinder portion through the descending piston.
Generally, this port is uncovered 50° before BDC and covered 50° after BDC

Additional Information
Working of Two-Stroke Engine:First Stroke (Suction and compression):

As the piston moves up from BDC towards TDC, it closes the inlet port, exhaust port, and transfer port.
Further upward movement of the piston results in compressing the mixture in the cylinder and opening the inlet port.
The upward motion of the piston creates a partial vacuum inside the crankcase below the piston, and the air/fuel mixture is drawn into the crankcase through the inlet port.
The exhaust and transfer port remain closed during the operation of the upward stroke and the charge which reached above the piston during the previous stroke is compressed.
Thus, suction and compression stroke takes place during the piston moves from BDC to TDC.

Second Stroke (power and exhaust):

The piston is forced down from the TDC.
During this stroke, the exhaust port opens and burnt gases escape into the atmosphere.
Further downward movement of the piston opens the transfer port and allows the partially compressed mixture, received during the previous stroke, to reach the combustion chamber from the crankcase.
The piston head has a spherical shape. It deflects a fresh charge of fuel mixture up into the cylinder.
The mixture flows down and pushes the burnt gases out, through the exhaust port. This process is called scavenging.