Section III. PRINCIPLES OF OPERATION
PRINCIPLES OF OPERATION.
The Diesel Engine Assembly, Hatz 2 G 40, is an internal combustion power unit that converts heat energy to work energy
inside the cylinders. This particular engine has a four-stroke cycle. A four-stroke engine completes one cycle every other
time the piston goes up and down (up being one stroke, down being the return stroke).
The first stroke is intake; the piston goes down in the cylinder and the intake valve opens, allowing air to
flow into the cylinder.
The second stroke is compression; the piston comes up and both valves close, so the air in the cylinder is
compressed. While the air is compressed, the fuel injector releases a spray of fuel into the cylinder.
The compression heats the air enough to ignite the fuel.
The third stroke is power; the fuel burns, forcing the piston down.
The fourth stroke is exhaust; the piston comes up in the cylinder and the exhaust valve opens, allowing
exhaust gas to escape.