The Stirling engine is basically a heat engine invented by Robert Stirling in 1816, the <a href=” />Stirling engine has the potential to be much more efficient than a gasoline or diesel engine.

A Stirling engine uses the Stirling cycle, which is unlike the cycles used in internal-combustion engines.

• The gasses used inside a Stirling engine never leave the engine. There are no exhaust valves that vent high-pressure gasses, as in a gasoline or diesel engine, and there are no explosions taking place. Because of this, Stirling engines are very quiet.

• The Stirling cycle uses an external heat source, which could be anything from gasoline to solar energy to the heat produced by decaying plants. No combustion takes place inside the cylinders of the engine.

The key principle of a Stirling engine is that a fixed amount of a gas is sealed inside the engine. The Stirling cycle involves a series of events that change the pressure of the gas inside the engine, causing it to do work.

There are several properties of gasses that are critical to the operation of Stirling engines:

• If you have a fixed amount of gas in a fixed volume of space and you raise the temperature of that gas, the pressure will increase.

• If you have a fixed amount of gas and you compress it (decrease the volume of its space), the temperature of that gas will increase.

The simplified engine uses two cylinders. One cylinder is heated by an external heat source (such as fire), and the other is cooled by an external cooling source (such as ice). The gas chambers of the two cylinders are connected, and the pistons are connected to each other mechanically by a linkage that determines how they will move in relation to one another.

However, there are a couple of key characteristics that make Stirling engines impractical for use in many applications, including in most cars and trucks.

Because the heat source is external, it takes a little while for the engine to respond to changes in the amount of heat being applied to the cylinder — it takes time for the heat to be conducted through the cylinder walls and into the gas inside the engine. This means that:

• The engine requires some time to warm up before it can produce useful power.

• The engine can not change its power output quickly.