It's true that they are rugged, but one of most important advantages of these engines is fact that they can be started by manual cranking. In remote areas, diesel engines can be counted upon for starting up from scratch.

Once a small diesel engine is started, it can be used to drive a small electrical generator that can then be used to produce electrical supply for driving other machines like pumps, compressors, and for lighting.

How does a diesel engine work?

First there must be combustion of fuel. As we have discussed in our previous articles, combustion or burning of fuel occurs whenever there is sufficient heat, fuel and oxygen. When conditions are just right, combustion can be very rapid. Rapid combustion causes an explosion in an enclosed area. This is because of rapid built-up of hot gases during process.

In an internal combustion engine like a diesel engine, this rapid combustion, and built-up of hot gas pressure is used to push a piston away from enclosed combustion space.

The piston is attached to a crankshaft through a connecting rod. Because of this, engine is able to convert linear movement of a piston to a rotating movement of a crankshaft.

As name suggests, these engines work on reciprocating actions of pistons. One stroke means one linear motion of piston in one direction. When piston moves in opposite direction, that is counted as another stroke.

For a 2-stroke engine, piston has to move up, and then down to complete one cycle of engine. In those 2 strokes of piston, crankshaft will have turned 1 revolution.

The 2 strokes of piston is to complete 4 stages of combustion cycle - air intake, compression, combustion and exhaust. As you might have known, in order for a fire (or explosion) to occur to power engine, we need a fuel, a heat source, and oxygen coming together at same time.

Remember how crankshaft and piston moves in a cylinder? The reciprocating movement of piston is converted to rotary motion by means of a crankshaft. The piston reciprocates between Top Dead Center and Bottom Dead Center inside cylinder liner.

One of most prominent feature of a 2-stroke engine is presence of air intake ports on cylinder liner that will enable fresh air to be led in for combustion.

These air inlet ports are cut into cylinder liner somewhere at lower end of latter. In a typical design, air inlet port are located about 35 degrees from Bottom Dead Center (BDC).

In many designs, fresh air that is introduced into cylinder is also used to drive out spent exhaust gases inside it. Many designs make use of scavenging air fans like electric blowers or turbochargers to slightly pressurize intake air before latter is introduced into cylinder.