AMP - Aviation Maintenance Technician Powerplant Practice Exam

What does "detonation" refer to in engine operation?

1. The controlled ignition of the fuel-air mixture

2. An imbalance in fuel-air mixture leading to stalling

3. The uncontrolled and explosive ignition of the fuel-air mixture

4. A method of reducing engine temperatures during operation

The correct answer is: The uncontrolled and explosive ignition of the fuel-air mixture

Detonation in engine operation specifically refers to the uncontrolled and explosive ignition of the fuel-air mixture within the combustion chamber. This phenomenon occurs after the normal ignition of the mixture due to the high temperatures and pressures present in the cylinder, causing a secondary ignition that produces a shock wave. This can lead to knocking or pinging noises and can significantly damage engine components, making it a critical factor for maintenance and operation. Understanding this concept is essential for aviation maintenance technicians, as detonation can impact engine performance and reliability. The other options describe different operational characteristics. For instance, the controlled ignition of the fuel-air mixture refers to proper combustion processes, while an imbalance in the fuel-air mixture could lead to other issues like stalling but does not describe detonation. The method of reducing engine temperatures pertains to engine cooling strategies and is unrelated to the ignition dynamics of the fuel-air mixture.