Mercedes-Benz_OM457_engine
Mercedes-Benz OM457 engine
Reciprocating internal combustion engine
The Mercedes-Benz OM457 Engine is a 12.0 L (11,967 cc) displacement inline 6-cylinder 4-stroke Diesel engine. It is one of many motors in the 400 series of engines, being an improved, electronically-managed version of the OM447. The OM457 has many applications, including trucks, marine, military, municipal, bus and agricultural vehicles, as well as stationary settings. The engine has many differing trim and power levels, ranging from around 250 to 450 horsepower, as well as both a vertically-mounted and, for buses, a horizontally-mounted version (denominated OM 457 hLA).
The engine is water-cooled and is produced using a cast-iron cylinder block, with removable wet type cylinder liners. The engine utilizes diesel fuel delivered in a direct injection method from individual electronically-controlled and camshaft-actuated unit pumps. The cylinder heads are separate units for each cylinder.
The crankshaft is a precision forged unit running in seven three-layer bearings, with counterweights bolted onto the crank webs, much like any other diesel motor of its vintage. The middle bearing is also the thrust bearing. The connecting rods are of a split design, with bronze bushings for the piston pin.