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Mercedes-Benz OM457 engine

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Mercedes-Benz OM 457
Overview
ManufacturerMercedes-Benz
Productionsince 1998
Layout
ConfigurationInline-6
Displacement12.0 L (11,967 cc)
Cylinder bore128 mm (5.0 in)
Piston stroke155 mm (6.1 in)
Cylinder block materialcast iron
Cylinder head materialcast iron
ValvetrainOHV
Compression ratio18.5:1
RPM range
Idle speed560
Max. engine speed2300
Combustion
Turbocharger1 × BorgWarner, no VGT
Fuel systemUnit injectors
ManagementElectronic
Fuel typeDiesel fuel 51 CZ, DIN EN 590 or EN 14214[1]
Cooling systemWater-cooled
Output
Power output185–335 kW (252–455 PS; 248–449 hp)
Torque output1.1–2.2 kN⋅m (811–1,623 lb⋅ft)
Dimensions
Length1,316 mm (51.8 in)[1]
Width746 mm (29.4 in)[1]
Height1,019 mm (40.1 in)[1]
Dry weight1,045 kg (2,304 lb)[1]
Emissions
Emissions target standardUp to Euro V or IMO IV
Emissions control systemsSelective catalytic reduction (BlueTEC) with Diesel exhaust fluid
Chronology
PredecessorOM447
SuccessorOM460 (Upstroked version to 12.8 L), OM471

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.

Data value[1]
Mercedes-Benz Type OM
Model 457.951 LA
Combustion cycle Four-stroke diesel with direct injection
Number and arrangement of cylinders vertical inline-6
Bore × Stroke, Displacement 128 mm × 155 mm (5.0 in × 6.1 in), 12.0 L (11,967 cc)
Compression ratio 18.5:1
Rated power 260 kW (354 PS; 349 hp) at 2000 rpm
Maximum torque 1.6 kN⋅m (1,180 lb⋅ft) at 1100 rpm
Cylinder firing order 1 - 5 - 3 - 6 - 2 - 4
Maximum pressure of injection nozzles 1,800 bar (26,000 psi)
Max. operating temperature 100 °C (212 °F)
Oil pressure nominal 2–5 bar (29–73 psi), idle min 0.5 bar (7.3 psi)
Weight, dry 1,045 kg (2,304 lb)

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