Table of Contents
How can knocking be Minimised?
In spark ignition (SI) engines, the possibility of knocking can be reduced by decreasing compression ratio as a reduction in compression ratio will result in the generation of lower peak temperature. The increase in temperature during the sparking will be higher.
What is knocking in petrol engine?
knocking, in an internal-combustion engine, sharp sounds caused by premature combustion of part of the compressed air-fuel mixture in the cylinder. Knocking can cause overheating of the spark-plug points, erosion of the combustion chamber surface, and rough, inefficient operation.
What does a knock in the engine mean?
What Is An Engine Knock? Knocking occurs when fuel burns unevenly in your engine’s cylinders. When cylinders have the correct balance of air and fuel, fuel will burn in small, regulated pockets instead of all at once. Engine knocking happens when fuel burns unevenly and those shocks go off at the wrong time.
What is knock control?
A knock control system which detects a knock occurring in an engine, a knock detector for detecting the occurrence of the knock in accordance with a knock sensor signal produced by the sensor, a first adjuster for adjusting knock control factors so as to suppress the knock on the basis of a detected signal from the …
What is knock adaptation?
Knock correction is the spark angle retard applied to the optimum ignition timing to eliminate knock. In adaptive knock control, this amount of spark retard at an operating point (i.e. Speed, load) is stored in a speed/load characteristic map. It will be reused when the engine is operated in this range once more.
What is knock threshold?
The knock threshold map sets the level of background noise that the ECU is going to ignore. The easiest way to set this up is to start and run the engine under conditions that you know the engine is not knocking and watch the “knock sensor signal”.
What is knocking in an engine?
Knocking is a phenomenon in an internal combustion engine that is a sharp sound that is caused due to the premature Detonation or combustion of some compressed air-fuel mixture in the combustion chamber or cylinder.
How to prevent engine knocking when using high octane fuel?
Apart from using fuel with a high octane rating, knocking can also be prevented by using spark plugs recommended by your car company, creating a slightly richer air-fuel mixture, possessing an engine with a lower compression ratio, etc. Adding a knock control sensor under the hood can further help one monitor this knocking phenomenon.
What happens if you knock on a spark plug too much?
Knocking may also overheat the spark plug and decay or rupture areas of the combustion chamber. More than anything, knocking causes the inefficient operation of the engine. The increased pressure because of knocking can lead to a variety of problems. Damage to engine parts and performance issues being the most critical.
What causes a knocking sound in a diesel engine?
Carbon deposition leads to a decrease in the overall cylinder volume. As a result, the mixture gets compressed significantly more, eventually inducing knocking. Using a faulty or incompatible spark plug and a low-octane fuel also leads to knocking.