decreasing the density of intake air

increasing the temperature of intake air

increasing the pressure of intake air

decreasing the pressure of intake air

cylinder walls being too hot

overheated spark plug points

red hot carbon deposits on cylinder walls

Any one of these

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.

To eliminate knock in compression ignition engines, we want to achieve auto-ignition not early and desire a long delay period.

In compression ignition engines, because of heterogeneous mixture, the rate of pressure rise is comparatively lower.

1/2

1/4

1/8

1/16

(ha-h2)/(h1-h2)

(h2-ha)/(h1-h2)

(h1-h2)/(ha-h2)

(ha-h1)/(h2-h1)