Delphi-Common Rail System – Judder damper

Sudden actuation of accelerator

1 Engine speed
2 Abrupt actuation of accelerator pedal (driver demand)
3 Engine speed curve without active judder damping
4 Engine speed curve with active judder damping
5 Time

There is a so-called software filter between the accelerator pedal calculation and the calculation unit.

When the accelerator is actuated or released suddenly, this causes huge changes in injected fuel quantity requirements and thereby also in the torque produced.

Owing to this abrupt load change, unpleasant jerking of the powertrain is caused in the elastic mountings (engine speed fluctuations. These are reduced by the judder damper as follows:
• as engine speed increases, comparatively less fuel is injected, as engine speed decreases more fuel is injected.

In addition, the software filter prevents an abrupt drop
in engine speed when changing gear.

Leave a Reply

Your email address will not be published.