Difference Between Two and Four Stroke Engines

Two vs Four Stroke Engines

When it comes to engines, two stroke and four stroke are classifications given to the internal combustion engines of an automobile. The difference is that in a two stroke engine there is only one upward and one downward stroke, giving a total of two movements in one cycle of the engine. In a four stroke engine, there are two upward and downward strokes, giving a total of four movements to complete one cycle of the engine.

The first stroke of a two stroke engine is the compression stroke, which is then followed by explosion of the fuel. In the second stroke, the new fuel mix is pushed into the cylinder. In a four stroke engine, the spark occurs inside the cylinder, and the cylinder already contains the burnt gases.

The sparkplugs in a two stroke engine last longer than those in a four stroke engine. Although, since two stroke engines do not have a separate lubricating system, its spare parts could wear out a bit faster compared to four stroke engines. Therefore, four stroke engines generally last longer than two stroke engines.

Two stroke engines are easier and less costly to manufacture because they have a simple construction and do not have any valves. Four stroke engines are much more complex in their design and construction, and therefore, their manufacture takes longer, and is more expensive.

Four stroke engines are much more fuel efficient than two stroke engines, as the latter will run for only a few miles on one gallon. Something else to consider, is that two stroke engines are responsible for much more pollution due to the combustion of oil in their engines. Four stroke engines are more environmentally friendly.

When it comes to power, a two stroke engine can produce twice the amount of power than a four stroke engine, in the same size engine. This is because it fires only once every revolution of the engine. A four stroke engine produces less power because it has four strokes per cycle.

Summary:

A two stroke engine has two strokes per cycle of the engine, while a four stroke engine has four strokes per cycle.

The sparkplugs in two stroke engines last longer than those in four stroke engines.

Two stroke engines are simpler and cheaper to manufacture compared to four stroke engines.

Four stroke engines are longer lasting than two stroke engines.

Four stroke engines are more fuel efficient and environmentally friendly when compared to four stroke engines.

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