Petroleum Engine basics

Petroleum Engine

Petroleum engine is an internal combustion engine with spark ignition that is using petrol (gasoline) as fuel. It is a machine that generates power by converting the potential energy of the fuel to heat and then to motion. It is very famous in our world today, as they have many applications like Automobiles, motorcycles, Aircraft, motorboats....etc. I will explain in this page the basic about the petroleum engines, so that everyone can get the principal idea about this brilliant invention.

History 

It was Nicolaus August Otto who invented the first practical four stroke internal combustion engine in 1876 which called "Otto Cycle Engine". His engine has a very significant contribution as it was universally adopted for all liquid-fueled automobiles after that. Another important contribution was from the German mechanical engineer, Karl Benz, who invented and built the world's first practical automobile in 1885 to be powered by internal combustion engine. His company became the world's largest manufacturer of automobiles by 1900.

 Working Principal

We can understand the working principal of the Petroleum engine by knowing the the working cycles or the working strokes. there are two main common cycles, the four cycles and the two cycles engines.

Four cycle Engine:

In the four cycle engine the piston complete four separates strokes while the crank shaft makes two turns. It is explained below in details:

1. Intake: This stroke of the piston begins at top dead center (T.D.C.) and ends at bottom dead center (B.D.C.). In this stroke the intake valve must be in the open position while the piston pulls an air-fuel mixture into the cylinder by producing vacuum pressure into the cylinder through its downward motion.

1. Compression: This stroke begins at B.D.C, or just at the end of the suction stroke, and ends at T.D.C. In this stroke the piston compresses the air-fuel mixture in preparation for ignition during the power stroke (below). Both the intake and exhaust valves are closed during this stage.

1. Power: This is the start of the second revolution of the four stroke cycle. At this point the crankshaft has completed a full 360 degree revolution. While the piston is at T.D.C. (the end of the compression stroke) the compressed air-fuel mixture is ignited by aspark plug (in a gasoline engine) or by heat generated by high compression (diesel engines), forcefully returning the piston to B.D.C. This stroke produces mechanical work from the engine to turn the crankshaft.

1. Exhaust: During the exhaust stroke, the piston once again returns to T.D.C from B.D.C while the exhaust valve is open. This action expels the spent air-fuel mixture through the exhaust valve.

Two Cycle Engine:

In the two cycle engine the piston complete four strokes while the crank shaft makes one turn only. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time.