FAQ: What Causes Detonation Aviation?

What causes detonation?

Detonation is generally caused by excessive heat, excessive cylinder pressure, improper ignition timing, inadequate fuel octane or a combination of these. Of the previous, excessive heat is usually the culprit.

How can aircraft detonation be prevented?

What causes detonation and how can it be prevented?

1. Increase the engine mixture.
2. Reduce power to a lower setting.
3. Reduce or stop climb and increase forward speed for greater cooling.

How can we prevent fuel detonation in aircraft engines?

Fuel with a higher octane rating will reduce detonation. Having said that, if you use a low octane fuel and start using a high octane fuel without changing anything else, you will increase the safety margin before detonation will occur. By itself, using a higher octane fuel will not increase the power of an engine.

Which condition is more dangerous to an aircraft engine pre ignition or detonation?

Detonation causes a very rapid pressure spike near the peak pressure point for a very brief period of time. Pre – ignition causes tremendous pressure that is present for a very long time – possibly the entire compression stroke. Not only is pre – ignition far more damaging, but it’s also much harder to detect.

How do you control detonation?

Investigations indicate that detonation may be controlled by retarding the rate of combustion by chemicals added to the mixture, which serve to increase its specific heat and prevent excessive temperature, and by reducing the temperature of the walls of the combustion-chamber, so that the temperature of the charge

What is difference between detonation and knocking?

In general, detonation is the cause and knocking is the after effect. Knocking is the result of the rapid combustion of end gas ahead of flame front prior to normal combustion. This cause a sharp rise of pressure inside the cylinder and cause metal pinging sound known as knock.

How is engine detonation diagnosed?

Optimize the Air/Fuel Ratio The result is a hot-running engine that will quickly build heat, and that can cause detonation. The best way to diagnose detonation in this situation is to install a wide-band oxygen sensor and monitor it during periods of high engine load.

What detonation sounds like?

detonation is refered to as “popcorn” or “bacon” noise, wich it sounds like frying bacon in the pan. It also can be described as somone taking a small ball peen hammer and tapping it on the side of the block.

How can we prevent pre-ignition in aircraft engines?

However, overheated spark plugs or other immediate components may also cause pre – ignition in aircraft piston engines. To prevent abnormal combustion in aircraft piston engines, operating limitations for the engine must be followed along with the use of properly refined and high-quality fuel.

What does detonation look like on a spark plug?

With the early signs of detonation, the shock-wave will also rattle rings causing the tiny amounts of oil that now gets by rings, to be fused to the white porcelain as tiny black specks, also fused as specks are soot that was clinging to clearance volume surfaces in the relatively “still-air” of the boundary layer.

What does detonation mean?

: to explode with sudden violence. transitive verb. 1: to cause to detonate detonate a bomb — compare deflagrate. 2: to set off in a burst of activity: spark programs that detonated controversies.

What is detonation in a car engine?

Knocking (also knock, detonation, spark knock, pinging or pinking) in spark ignition internal combustion engines occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but one or more pockets of air/fuel mixture explode

Can running too rich cause knock?

You will get knock from being too rich, but it isn’t false. The fuel is still predetonating, and can still cause damage to engine internals.

Can bad spark plugs cause detonation?

A piston destroyed by preignition because the air/fuel mixture went too lean under hard load. The wrong spark plugs can cause detonation. Spark plugs with the wrong heat range (too hot) can cause detonation as well as preignition.

What is the critical altitude?

Critical altitude is the maximum altitude where the engine turbochargers (or turbonormalizers) can maintain sea level standard pressure to the engines. Above the critical altitude the engines will produce less power, although still delivering more power than an normally aspirated engine at the same air density.