OM611

Mercedes-Benz developed the system with Bosch, and the principle was a break with everything before it. Rather than raising pressure separately for each injection event, a shared rail holds it — up to 1,350 bar, available from low engine speeds — and solenoid valves meter it to the nozzles, with the timing of each event freely variable. Shown at Frankfurt that September as the C 220 Turbodiesel and launched three months later as the C 220 CDI, the 2.2-liter OM611 delivered 125 PS and 300 N·m from 1,800 rpm. Against the prechamber engine it replaced: thirty per cent more power, twice the torque, ten per cent less fuel.

The four-cylinder came first and the five-cylinder OM612 and six-cylinder OM613 followed in 1999, by which time CDI had spread through the W202 and W203 C-Class, the W210 E-Class, the V-Class and the facelifted Sprinter, in ratings from 82 to 143 PS. The W211 of 2002 moved to the OM646 and Mercedes-Benz stopped building the OM611 in 2006 — but not everyone did. Force Motors, which had been assembling Mercedes diesels in India since the OM616, used it in the Force One and the Gurkha Xtreme.