What is the difference between Internal Combustion Engine and External Combustion Engine?

In an Internal Combustion Engine, the Fuel is burnt in the cylinder or vessel eg. Diesel or Petrol engine used in Cars.

In an External Combustion Engine, the internal working fuel is not burnt. Here the fluid is being heated from an external source. The fuel is heated and expanded through the internal mechanism of the engine resulting in work. eg. Steam Turbine, Steam engine Trains.