Purpose of different piston heads
- Flat head: The simplest and most common type of piston head. It is easy to manufacture and provides a good seal against the cylinder wall. However, it is not as efficient as other types of piston heads, as it does not provide an ideal combustion chamber shape.
- Flat head with valve recessed: This type of piston head has small recesses machined into it to accommodate the valves. This helps to prevent the valves from hitting the piston head at high RPMs.
- Cupped head: This type of piston head has a concave cavity machined into the top. This helps to create a more efficient combustion chamber, as it concentrates the fuel-air mixture in the center of the cylinder. However, it is more difficult to manufacture than a flat head.
- Domed head: This type of piston head has a convex dome machined into the top. This also helps to create a more efficient combustion chamber, but it is more prone to detonation (premature combustion of the fuel-air mixture) than a cupped head.
Most common type of piston head in aviation
The most common type of piston head in aviation is the flat head with valve recessed. This is because it is simple to manufacture, provides a good seal against the cylinder wall, and is less prone to detonation than a cupped or domed head.
However, some high-performance aircraft engines use domed heads to improve efficiency and power output. These engines are typically equipped with knock sensors to detect and prevent detonation.
Additional notes
- The type of piston head used in an engine depends on a number of factors, including the engine’s compression ratio, operating speed, and fuel type.
- Piston heads are typically made of aluminum alloys, which are lightweight and have good heat transfer properties.
- Piston heads can also be coated with special materials, such as ceramic, to improve their durability and resistance to wear and tear.