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Mercedes-Benz OM642 engine
The Mercedes-Benz OM642 engine is a 3.0 litres (2,987 cc), 24-valve, aluminium/aluminium block and heads diesel 72° V6 engine manufactured by the Mercedes-Benz division of Daimler AG as a replacement for the Mercedes straight-5 and straight-6 cylinder engines.[1] By 2010 a BlueTEC version of the Mercedes Sprinter OM642 was released. The BlueTEC systems allowed the elimination of much of the EGR in that vehicle's engine, which as a result gave 188 horsepower (140 kilowatts) compared to the non-BlueTec engine's 154 horsepower (115 kilowatts).[2] The engine features common rail Direct injection and a variable nozzle turbocharger. The injection system operates at 1,600 bar (23,000 psi), while the compression ratio is 18.0:1.[1] The engine features a counter-rotating balance shaft mounted between the cylinder banks to cancel the vibrations inherent to the 72 degree V6 design, and the crankpins are offset by 48 degrees to achieve even 120 degree firing intervals. In some heavy vehicle applications, Mercedes' BlueTec AdBlue urea injection is utilised for NOx reduction.[3] In lighter vehicle applications, a NOx storage catalyst captures nitrous oxides, which are periodically purged (decomposed) by running the engine slightly rich. A particulate filter lowers soot, making this engine ULEV certified.[3][4] Engine mass is 208 kg (459 lb). Power output is 165 kW (224 PS; 221 hp) and 510 N⋅m (376 lb⋅ft) of torque.[1] For the 2007 model year, torque is raised to 540 N⋅m (398 lb⋅ft). At the beginning of summer 2017 the engine, together with Mercedes-Benz OM651 was under investigation by the Federal Motor Transport Authority in respect of the alleged emissions cheating scandal wherein the laboratory emissions testing produced a different amount of diesel exhaust fluid usage and lower emissions than in real world operating scenarios. [5] ImplementationVehicles using this engine include:
Intake SystemAir is drawn into the engine through two air filters located above each cylinder head. The amount of the air is measured by two hot film mass air flow sensors B2/6&7. On Sprinter models, a single air filter housing is mounted upon brackets on top of the engine.  The variable geometry turbine is actuated via a linkage connecting the controller to vanes inside the turbine housing. With the VGT vanes in a closed position, the exhaust gases are accelerated into the turbine wheel blades increasing shaft speed thereby increasing boost. With the vanes in the open position the exhaust gases are decelerated causing a drop in the shaft speed and consequent drop in boost.  See alsoReferences
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