Air-cooled engine: What are its advantages and disadvantages?

Honda RC174E engine
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An air-cooled engine is an internal combustion engine in which cooling and maintaining optimum engine temperature is ensured using flowing air.

In today's article, we will briefly look at the air-cooled engine, its division, as well as the advantages and disadvantages of this engine.


How does an air-cooled engine work?

With air cooling, the heat from the hot parts of the engine is removed by the airflow. To achieve a sufficient cooling effect, the cooled parts (cylinder head, cylinder block, or individual cylinders) must have the largest possible contact surface with the air.

For this reason, the components above of air-cooled engines are equipped with cooling fins that increase the contact area with the air.

Air cooling of the engine is mostly used for small engines, lawnmowers, and motorcycles, but it has also found its way into cars and almost all propeller-driven aircraft. In the automotive world, liquid cooling is predominantly used today, replacing air cooling due to better cooling regulation.

With many air-cooled engines, ensuring perfect heat regulation is a big problem; that is why these engines are undercooled in the winter and overheated in the summer.

To eliminate this problem, the air-cooled engine is equipped with automatic cooling regulation, which maintains the optimal temperature of the cylinders. Even this cannot ensure uniform cooling of every thermally stressed engine part.

According to the way the air flows, we divide air cooling into:

  1. Forced air cooling
  2. Natural air cooling
  3. Forced air cooling

1. Blast air cooling

Blast cooling occurs while driving and is only used for low-power engines like motorcycles.

2. Natural air cooling

Natural cooling is realized by natural air circulation and is mainly used in lawnmowers.

3. Forced air cooling

Forced cooling uses a device to create an air stream. The airflow is often created by a fan driven by a V-belt from the engine crankshaft. This type of air cooling is mainly used in car engines.

Air-cooled engine and its advantages:

  • simple design does not contain a cooler, liquid distribution, water pump, nor complex cooling channels in the cylinder block and engine head - lower engine weight
  • low maintenance
  • high reliability
  • the engine reaches operating speed faster temperature

Air-cooled engine and its disadvantages:

  • uneven thermal load on individual parts of the engine
  • the higher temperature of the engine and its components
  • higher engine noise
  • the lower power of the engine is caused by the fan, which is driven via the V-belt