Detonation – Detonation, as the name suggests, is an explosion of the fuel-air mixture inside the cylinder. It occurs after the compression stroke near or after top dead center. During detonation, the fuel/air charge (or pockets within the charge) explodes rather than burning smoothly.
What is meant by detonation in an aircraft reciprocating engine?
Detonation is the abrupt combustion or explosion of the fuel charge inside the cylinder. … Light detonation may not show any indication in the cabin of the aircraft. Moderate to severe detonation could be noticed as engine roughness, vibration or loss of power and eventually engine damage.
What is detonation What are the effects of detonation?
What are the Harmful Effects Of Detonation In Engine ? Detonation (also called “spark knock”) is an erratic form of combustion that can cause head gasket failure as well as other engine damage. Detonation occurs when excessive heat and pressure in the combustion chamber cause the air/fuel mixture to autoignite.
What is the most common cause of detonation in an engine?
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. As an engine is modified to generate more power, additional heat is produced.What is the difference between knocking and detonation?
Knocking vs Detonation Knocking is the making sharp sounds due to uneven combustion of fuel in the cylinder of a vehicle engine. Detonation is the process of pre-ignition or auto-ignition of a fuel in an engine’s combustion chamber.
How do you fix detonation?
- #1. Up Your Octane. …
- #2. Keep Compression Reasonable. …
- #3. Check Your Timing. …
- #4. Manage Your Boost. …
- #5. Monitor the Mixture. …
- #6. Blow out the Carbon. …
- #7. Examine Your Knock Sensor. …
- #8. Read Your Spark Plugs.
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.
Can low oil cause detonation?
The oil has a significantly lower auto-ignition temperature and will ignite early causing detonation in sufficient volumes.What factors could affect detonation in an engine?
- Compression ratio: The pressure and temperature at the end of compression increases with increase in compression ratio. …
- Supercharging: …
- Increasing inlet temperature: …
- Increase in load: …
- Advancing the spark: …
- Flame travel distance: …
- Spark plug location: …
- Engine size:
Discovered in 1881 by French scientists, detonation is the result of a supersonic wave initiating a secondary explosion. … Explosion, on the other hand, is a general term for an accelerated release of energy generating extreme temperatures, releasing of gases and expanding volume.
Article first time published onWhat causes detonation in a two stroke engine?
Detonation, unlike a normal engine combustion process, is a condition where the fuel and air inside of the combustion chamber spontaneously combusts or “explodes” rather than burning at a very specific c rate. This spontaneous combustion occurs as a result of having a combination of excessive heat and pressure.
How detonation or knocking affects the performance of SI engine?
The usage of hydrogen in compression ignition engine leads to production of knocking or detonation because of its lower ignition energy, wider flammability range, and shorter quenching distance. Knocking combustion causes major engine damage, and also reduces the efficiency.
What should be the first action after starting an aircraft engine?
What should be the first action after starting an aircraft engine? Adjust for proper RPM and check for desired indications on the engine gauges.
What is detonation explain in detail?
Detonation (from Latin detonare ‘to thunder down/forth’) is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it.
In which engine detonation occurs in the beginning of combustion?
Solution: –In compression ignition engines, detonation occurs near the beginning of combustion. -Since the fuel, in compression ignition engines, is injected at the end of compression stroke, therefore, there will be no pre-ignition.
What is knocking and detonation and its causes?
“Knocking” and “detonation” are the interchangeable terms refers to the phenomenon of uncontrolled combustion in the IC engine. “Knock” is the sharp metal pinging sound produced in the engine due to uneven combustion. … In general, detonation is the cause and knocking is the after effect.
Can bad spark plugs cause detonation?
The wrong spark plugs can cause detonation. Spark plugs with the wrong heat range (too hot) can cause detonation as well as preignition.
How do you check engine detonation?
- Knocking or pinging sound.
- Drop in Exhaust Gas Temperature (EGT)
- Broken piston rings and/or spark plugs.
- Damage to the piston and/or valves.
Can Cam Timing cause detonation?
This creates a tremendous amount of pressure inside the cylinder which = power. You can only advance the timing just so far though before the fuel burn becomes and uncontrolled burn or “explosion” (detonation or “pinging”), which can cause serious damage to pistons, rings, head gaskets, etc.
How does SI engine reduce detonation?
- Increasing the cooling water temperature.
- Retarding the spark advance.
- Increasing the inlet air temperature.
What is pinging and detonation?
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 …
Does running rich prevent detonation?
The ethanol content’s high effective octane rating suppresses detonation in high-compression-ratio racing engine if the air/fuel ratio is rich. That would be a lambda of less than one in the EFI computer world. A rich alcohol fuel mixture also cools the cylinder away from auto-ignition temperatures.
Does low octane fuel cause detonation?
There are several causes for detonation. Perhaps the most common is low octane – lower than you might suspect – gasoline. … Severe detonating can raise combustion chamber temperatures from normal to well above the melting point of many metals, causing potentially serious damage to pistons and valves.
Will running lean cause detonation?
Unfortunately a lean mixture can also lead to detonation and higher temperatures which can destroy or reduce the life of the piston and cylinder. As such, a lean mixture should be avoided for high power settings.
What is a detonation wave?
A detonation is a supersonic combustion wave that consists of a shock wave driven by energy release from closely coupled chemical reactions. These waves travel at many times the speed of sound, often reaching speeds of Mach 5, as in the case of a hydrogen–air fuel mixture.
What explosive has the highest detonation velocity?
Octanitrocubane has a detonation velocity of 10,100 m/s, making it the fastest known explosive. Small amounts have been synthesized in the laboratory, but not enough for performance testing as an explosive.
What is Intermagazine distance?
Intermagazine distance (IMD): The minimum separation distance between magazines. 18. Possessor of Explosives: Is someone who has actual physical possession or constructive possession, which means the person has dominion or control over explosives.
What causes pre ignition?
Pre-ignition is the ignition of the air- fuel charge while the piston is still compressing the charge. The ignition source can be caused by a cracked spark plug tip, carbon or lead deposits in the combustion chamber, or a burned exhaust valve, anything that can act as a glow plug to ignite the charge prematurely.
What is 2stroke pinging?
When people say that their bike is pinging they are generally referring to it pre-detonating. This means that the combustion mixture inside the cylinder is exploding before the piston reaches the top of its stroke. This causes massive strain on the engine and can result in severe failure if not taken care of.
What gives a 2 stroke spark?
The cylinder is completely filled with fresh charge and somewhat diluted with the remaining exhaust gases. The engine burns this charge during the next upward stroke. This cycle repeats itself and the piston makes two strokes for each revolution of the crankshaft.
Which of the following factor decreases the detonation in SI engine?
Explanation: In SI engine, due to the increment of the initial temperature and pressure are ignition lag is reduced.
