What causes detonation knock?
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What causes detonation knock?
Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition. Detonation is generally caused by excessive heat, excessive cylinder pressure, improper ignition timing, inadequate fuel octane or a combination of these.
What is auto-ignition detonation and knocking?
‘Knock’ is caused by the self-ignition of the unburned fuel/air mixture after the spark has fired. Auto-ignition is the self-ignition of the fuel/air mixture before the spark has fired. This can be caused by hot combustion residuals or hot parts of the cylinder wall.
What is detonation of an engine?
Detonation—sometimes called knock or pre-ignition—is a pinging sound that can sometimes be heard during acceleration and throttle tip-in. Unlike normal exhaust noise, detonation is a higher-pitched, raspy note that emanates from the engine compartment.
What are the differences between detonation knocking and preignition?
Detonation is an uncontrolled combustion event which occurs after the spark event. Pre-ignition is an uncontrolled combustion event which occurs before the spark event. Knock (pinging) is the actual noise that can be audibly heard if detonation is bad enough.
What is the difference between detonation and pre-ignition?
Pre-ignition is the ignition of the air- fuel charge while the piston is still compressing the charge. 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.
What do you understand by knocking?
knocking, in an internal-combustion engine, sharp sounds caused by premature combustion of part of the compressed air-fuel mixture in the cylinder. In a properly functioning engine, the charge burns with the flame front progressing smoothly from the point of ignition across the combustion chamber.
How do you fix a detonation knock?
Detonation Elimination: 9 Ways to Prevent Engine 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.
What is the difference between auto-ignition and pre-ignition?
The key point here is that auto-ignition occurs after normal combustion has been initiated with the spark plug. Pre-ignition is defined as the ignition of the mixture prior to the spark plug firing.