Mercedes-Benz new OM654 2.0 litre turbodiesel engine detailed – 14 hp up, 13% more efficient, 17% lighter

Mercedes-Benz has revealed and detailed a brand-new 2.0 litre four-cylinder turbocharged diesel engine that will be used across its global model range. Known internally as OM654, the 1,950 cc engine is here to take over from the 2.1 litre (2,143 cc) four-pot turbodiesel referred to as OM651, that has been around since 2008.

The outgoing diesel mill was the most-produced engine in Mercedes-Benz history, and has since served in the A-Class to the S-Class, from the V-Class to the Sprinter van. The new engine will gradually take over these duties, spreading its performance and efficiency gains widely across the entire Mercedes-Benz range.

Clearly, the new engine will have a mountain on its shoulders from the start. Its first application has been set for the new W213 Mercedes-Benz E-Class (E 220d in March 2016), but just like the engine it replaces, it has also been developed for use in the brand’s growing range of hybrids and as well as all vehicles with transverse or longitudinal engine configurations – front or rear wheel drive, too.

Several tunes of the engine will be available, but Mercedes-Benz has only detailed what the engine’s key specs would look like powering the new W213 E 220d. As seen below, the engine offers 194 hp and 400 Nm of torque – 14 hp more than before, but maintaining the same torque figure as before.

Whilst being 13% more fuel efficient than before, the new E 220d will also be able to perform the century sprint in 7.3 seconds, which is 0.9 seconds quicker than the outgoing W212 E 220d BlueTEC (8.2 seconds). Interestingly, max horsepower arrives 800 rpm later in the new engine. Peak torque is also slow to arrive, taking 200 rpm longer to hit, yet falling off 400 rpm earlier than the previous powerplant.

The car maker has also decided to switch from a two-stage turbo setup (on “250” variants i.e. E 250d) to a single turbocharger where applicable. The turbo features a variable nozzle turbine with a water-cooled bearing housing and an e-actuator. Note that the previous OM651 engine only offered a two-stage turbo on “250” variants like the W212 E 250d.

The operation of the turbo in the new engine is managed by a Multicore microcontroller, which together with the new single turbo, is said to improve real-time performance with lower power consumption. The cylinder spacing for the engine has been reduced from 94 to 90 mm compared to the previous engine, contributing to the overall compactness of the engine.

This is also Mercedes-Benz’s first all-aluminium four-cylinder engine. Thanks to the lightweight construction, reduced displacement and move from two-stage to single-stage turbocharging, the OM654 engine is 17% lighter (168.4 kg) than the outgoing OM651 (202.8 kg). The car maker also claims that the engine has reduced levels of noise, vibrations and harshness (NVH) in comparison with the outgoing model.

More importantly, Mercedes-Benz says that its new OM654 engine is designed to meet future emissions legislations using the Real Driving Emissions tests, and not the unrealistic NEDC test cycle the current figures are based on.

“In contrast to the current NEDC measurement cycle, the Worldwide-harmonized Light vehicles Test Procedure (WLTP) cycle is aimed at ensuring that the figures for standard and real-world consumption are close together in future. In addition, it is planned in Europe to introduced a measuring procedure for Real Driving Emissions (RDE). This, too, is actively supported by Mercedes-Benz,” the company explains.

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