Mercedes-Benz OM 608 diesel engine

Mercedes Benz
OM 608
Manufacturer:	Renault
Production period:	since 2018
Style:	Four-cylinder in - line engine
Engines:	1.5 liters (1461 cm³)
Previous model:	Mercedes-Benz OM 607
Similar models:	Renault K9K

The Mercedes-Benz OM 608 is a four-cylinder - diesel engine of Daimler AG and comes from the strategic cooperation with Renault-Nissan . This is the successor to the OM 607 and is offered in the A-Class ( W 177 ) .

The basic engine is identical to the Renault K9K engine. Among Mercedes-specific components include the start-stop function, the ancillaries ( air conditioning compressor and generator ), a special dual-mass flywheel, a modified engine control unit with additional features and exhaust aftertreatment.

The displacement of the four-cylinder in - line engine is 1461 cc with a bore of 76 mm and a stroke of 80.5 mm. The compression ratio is 15.1: 1. The crankcase of the engine is made of gray cast iron, the cylinder head of an aluminum alloy. As with the Mercedes-Benz OM 622 / OM 626 , Mercedes-Benz OM 654 and Mercedes-Benz OM 656 , steel pistons are used. 

Compared to the predecessor u. a. reduced the height of the aluminum cylinder head and integrated the intake manifold in the cylinder head cover. The charge cycle is controlled by two valves per cylinder and an overhead camshaft ( OHC valve control ).The engine has an exhaust turbocharger with variable turbine geometry , the vanes are adjusted load-dependent via an electric actuator.To reduce pollutant emissions, the OM 608 is equipped with high-pressure and low-pressure exhaust gas recirculation . 

The exhaust aftertreatment arranged close to the engine takes place in contrast to the predecessor OM 607 with the help of an SCR system . Behind the turbine of the turbocharger comes first a diesel oxidation catalyst (DOC) is used, then the urea solution AdBlue required for the purification of nitrogen oxides is metered. After a short mixing section, an SCR-coated diesel particulate filter (sDPF) and an SCR catalytic converter follow each other . The engine is certified according to Euro 6d TEMP. The common-rail injection works with a fuel pressure up to 2000 bar.