Answer: Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition. This means that a powerful explosion is trying to expand a cylinder chamber that is shrinking in size, attempting to reverse the direction of the piston and the engine.
What is an example of detonation?
Examples include primary explosives such as nitroglycerin that can detonate with little or no stimulus and secondary explosives such as dynamite (trinitrotoluene, TNT) that require a strong shock (from a detonator such as a blasting cap). Low explosives change into gases by burning or combustion.
What is the difference between an explosion and a detonation?
Explosion is a general term for an accelerated release of energy generating extreme temperatures, releasing of gases and expanding volume. Discovered in 1881 by French scientists, detonation is the result of a supersonic wave initiating a secondary explosion.
What is a detonation in English?
/ (ˌdɛtəˈneɪʃən) / noun. an explosion or the act of exploding. the spontaneous combustion in an internal-combustion engine of part of the mixture before it has been reached by the flame front, causing the engine to knock. physics rapid combustion, esp that occurring within a shock wave.
How is detonation diagnosed?
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. A lean condition under full throttle can induce knock at ratios as low as 13:1, and that should tell you not enough fuel is reaching the cylinder.
What happens in detonation?
Detonation is the abrupt combustion or explosion of the fuel charge inside the cylinder. In simplified terms, when detonation occurs, the fuel charge ignites quickly in an uncontrolled explosion, causing a pounding or hammering force on the piston rather than a steady push.
What causes detonation?
What Causes Detonation? The type of engine damage caused by detonation happens when a heat source within the combustion environment ignites the fuel/air charge prior to initiation by the engine’s ignition system.
What is the most powerful explosive in the world?
One of the most powerful explosive chemicals known to us is PETN, which contains nitro groups which are similar to that in TNT and the nitroglycerin in dynamite. But the presence of more of these nitro groups means it explodes with more power.
How does detonation cord work?
Detonation Cord consists of a high-explosive (either PETN or RDX) core wrapped in a reinforced, waterproof, olive-drab plastic coating that transmits a detonating wave. When the explosive core is detonated by a blasting cap, the wave travels along the cord to other blasting caps or explosive charges attached to it.
What is fuel detonation?
Detonation is the abrupt combustion or explosion of the fuel charge inside the cylinder. During normal combustion, the spark plugs ignite the fuel charge and the fuel has a consistent and even burn as the piston moves through the power stroke and chemical energy is efficiently converted to mechanical.
What is a high explosive?
High explosives consist of materials that typically combine the reacting elements in the same molecule. This allows them to react much faster, and they “detonate.” Detonation involves supersonic shock waves that pass through the material, causing chemistry that happens quite a bit faster than burning.
What does detonation feel like?
When detonation happens, some of the air/fuel ignites before the normal burn can get to it. This causes a brief, but intense, spike in cylinder pressure. Detonation is also called an “Engine Knock”, “Knocking”, or “Pinging” because of the sound it makes.
Which is the best definition of detonation?
Definition of detonation. 1 : the action or process of detonating. 2 : rapid combustion in an internal combustion engine that results in knocking.
Where does the detonation of an engine take place?
The mixture is ignited by the spark, normally in the centre of the cylinder, and a flame front moves from the spark towards the outside of the cylinder in a controlled burn. Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition.
Why is detonation a dirty word around hot rods?
Detonation is a dirty word around hot rods. Nobody likes to talk about it because when it happens, it usually means some lapse of attention during engine or vehicle assembly has occurred. By the time you hear the characteristic death rattle of an engine in the throes of detonation, the damage has most likely already been done.
What happens if a detonation is left unchecked?
Detonation can cause catastrophic engine failure if left unchecked. That’s why most modern engines incorporate a failsafe in the factory tune to retard ignition timing or add fuel when a knock sensor detects too high of a knock count.
