1 - a sharp change in the position of the accelerator pedal by the driver
2 - curve of the frequency of rotation of the crankshaft of the engine without active shock absorber
3 - curve of the frequency of rotation of the crankshaft of the engine with an active shock absorber
When the accelerator pedal is depressed or released sharply, the amount of fuel injected should change rapidly, which should lead to an equally rapid change in engine speed. These abrupt changes in load result in the generation of oscillations which are based on oscillations from the engine speed.
An active damper reduces these periodic oscillations in the engine speed by changing the amount of fuel injected at a rate corresponding to the engine speed: when the accelerator pedal is pressed hard, less fuel is injected and when the pedal is released sharply, more fuel is injected. This effectively reduces the instantaneous bursts of engine speed.