The diesel engines: From the S-Class to the CLA-Class

Mar 6, 2013
The CLA 220 CDI combines sporty handling with exemplary efficiency and already complies with the Euro 6 exhaust gas standard, which will only become mandatory from 2015. The ECO start/stop function is featured as standard. The CLA 200 CDI is due to follow in September.
Since its world premiere in 2008 the direct-injection diesel engine known as the OM 651 has been setting standards in terms of performance and torque characteristics, economy, emissions and smooth running. It is in more widespread use than any other Mercedes-Benz diesel engine and is an exemplary model of efficiency and power right up to the S-Class. For transverse installation the belt drive for the ancillary units, the installed position of the turbocharger and the air ducting have been modified.
Dynamic in its handling, extremely efficient and of exemplary cleanliness: the CLA 220 CDI, available exclusively in combination with the 7G-DCT dual clutch transmission. The 125 kW (170 hp) top diesel with a displacement of 2.2 litres and a peak torque of 350 Nm, features a weight-optimised crankshaft and, with its individual bearing covers bolted from below and four counterweights, weighs around six kilograms less than an OM 651 of the same displacement, in the longitudinal-installation variant. The CLA 220 CDI is equipped with a multi-path exhaust gas recirculation system which reduces the nitrogen oxide emission levels.
Already today it meets the Euro 6 exhaust gas standard which will be compulsory from 2015. With 109 g CO2 per km and a combined fuel consumption of 4.2 litres per 100 km, the CLA 220 CDI sets new standards in its segment with 8.2 seconds for the standard sprint and a top speed of 230 km/h, its performance is of sports car level.
At 2.2 litres, the engine is relatively large-displacement, which makes it agile already at low speeds. Mercedes-Benz engine experts call this combination of large-displacement engine and low engine speeds "downspeeding". This made it possible for the ECONOMY gearshift program of the 7G‑D CT transmission to be decidedly economical and comfortable. If the driver selects "S", gearshifts are performed much faster and the ratio spread uses the rpm reserves of the engine for dynamic performance.
The CLA 200 CDI can be ordered from 8 April 2013, the first vehicles will be delivered to customers from September 2013. Its top output is 100 kW (136 hp), its maximum torque, 300 Nm. The displacement was reduced to 1.8 litres by shortening the stroke (83 mm instead of 99 mm). The significantly longer connecting rods ensure lower transverse friction, and the two Lanchester balancer shafts also have a low-friction design. The single-stage turbocharger has been optimised for efficiency and features adjustable vanes. With a distance between cylinders of 94 millimetres and cylindrical gears driving the camshafts, transverse installation and the short length required were part of the design specification from the very start.
Overview of technical data for the CLA-Class with diesel engine
CLA 200 CDI*
CLA 220 CDI**
Number of cylinders/arrangement
Rated output
[kW/hp] at [rpm]
Rated torque
[Nm] at
Fuel consumption, combined
[l/100 km]
4.2 – 4.5
CO2 emissions, combined
109 – 117
* available from September 2013, ** with dual clutch transmission (7G-DCT), n/a = no data available yet
Mercedes-Benz CLA-Class, CLA 220 CDI, engine
Mercedes-Benz CLA-Class, CLA 220 CDI, power output graph (german version)
Mercedes-Benz CLA-Class, CLA 220 CDI, power output graph