The OM646 is a turbocharged inline-four engine produced between 2002 and 2010 by Mercedes-Benz.

The OM646 engine is sold under the 200 CDI and 220 CDI designation and features an electric fuel pump, exhaust gas recirculation, particulate filters,[1] and Euro 4 emission standard compliance (from 2003).

[2] In 2006, the engine was updated under the EVO name and replaced the OM647 engine.

It features a reduced compression ratio of 17.5:1, a new turbocharger, and ceramic glow plugs for improved engine starts.

[3]