As per the test drive reported in today Hindu "The common-rail system developed by Delphi, operates at a pressure of 1,600 bar, and can provide five injections per stroke; but in the Indigo, these are limited to three squirts per stroke. More injections mean a smoother engine. For now, Tata has elected to go with three injections per stroke until the Bharat Stage IV emission norms come in."
here is the link
The Hindu : Metro Plus Bangalore / Wheels : Straight to the heart