Diesel knock

Diesel knock is knocking in a diesel engine.
The longer the ignition delay period, the more the amount of fuel injected (amount vaporized) into the cylinder will increase.
Therefore, if spontaneous ignition occurs, the fuel will combust all at once, resulting in a sudden increase in pressure and creation of a shock wave that acts to cause a knock phenomenon. This is referred to as diesel knock.
Diesel knock is closely related to the ignition delay period and the uncontrolled combustion period.
In order to prevent diesel knock, the fuel ignition delay period should be shortened and the vaporization mixture during that period should be reduced, but
this requires the use of fuel with good ignitability, raising the compression ratio, raising pressure and temperature inside the cylinder, and reducing injection quantity at the start of fuel injection.