Internal Combustion Engines: What Is It And How It Works

An internal combustion engine is one that uses the chemical energy in the fuel to produce heat inside the engine. This is referred to as an internal combustion engine (Ferguson-Kirkpatrick 2015).

Due to the combustion in fuels like diesel and petrol, there is an increase in the pressure. This forces the piston down and converts chemical energy into mechanical energy.

Here are some highlights

Nikolaus Otto, an engineer from Germany, created the first four-stroke engine that had in-cylinder compression in 1876. He called it the “Otto Silent Engine”.

A. de Rochas had however in 1861 patented and conceived the idea for a four stroke engine.

Sir Dugald Clerk, an engineer from Scotland, invented and built the first two stroke engine. This engine was then patentable in 1881.

Rudolph Diesel was a German engineer who developed the first fourstroke engine using direct injections of liquid fuel. The engine’s high compress ratio allowed for combustion and auto-ignition (Ferguson/Kirkpatrick, 2015).

How it works (Two Stroke Motor)

The functions of a two stroke engine are the same as those of a four-stroke one, but the engine does it in only two piston strokes instead of four.

This can be done in two-stroke engines with simple crankcases. These engines are known as crankcase-scavenged 2-strokes.

Just below Top Dead Center(TDC), the sparkplug releases a spark, which ignites the gasoline. This causes enough energy to propel the piston downward.

The piston closes to the Bottom Dead Center (BDC) but the mixture fuel, air and oil continue to move up the transfer port and into the cylindrical. The piston will cover the transfer ports first, then leave only the exhaust port unlocked to allow exhaust gases from the combustion chamber to escape.

It is impossible to lubricate engines in other ways so oil is mixed into the fuel. Unburnt oil can be characterized by black smoke and petrol-like odors from the exhaust.

A 4-stroke engine has 4 strokes. These are:

Ingestion

Squeezing

Widening, enlargement

Exhaust

Stroke 1 – Intake – An intake valve is an opening that allows air or a mixture of air and fuel to enter. Suction is created by the piston’s downward movement. The combustion chamber is able to take in the air/fuel mixture due to the suction. The intake valve opens at the stroke’s beginning and closes after the stroke is over to increase the volume of fresh mixture that is inducted.

Stroke 2 is compression – The mixture will be compressed to a fraction it original volume. The intake and exhaust must be kept closed to ensure this stroke is as effective as possible. To increase the pressure in the cylinders, rapid combustion occurs at the end.

Stroke 3, Expansion: The mixture is pressurized, and the piston is pushed to the bottom. The exhaust valve opens once the piston reaches BDC to start the Exhaust stroke.

Stroke 4 is Exhaust. This stroke removes all combustion fuel from the combustion chamber, allowing for the creation of fresh mixture. To ensure that all fuels are removed from the system, the piston is moved towards the top dead center (TDC). The four strokes are restarted when the exhaust valve closes just before TDC.