2014 E250 BlueTEC. Click to enlarge.

The all-aluminum, in-line four-cylinder diesel engine makes use of four valves per cylinder and dual overhead camshafts with vane-type variable valve timing, producing 195 hp (145 kW) and 369 lb-ft (500 N·m) of torque.

To smooth out the inherent vibration of an in-line four-cylinder engine, two Lanchester balance shafts spin at twice crankshaft speed in low-friction roller bearings. During normal operation, the advantages of this two-stage turbocharged system can be felt—no turbo lag, fast throttle response, a broad torque curve across the entire engine speed range and noticeably improved performance. The 369 lb-ft of torque is readily available at 1,800 rpm.

Fuel pressure for the BlueTEC direct fuel injection system is 2,000 bar, which makes possible even more power and lower exhaust emissions. Higher ignition fuel pressure means the four piezo injectors can be adjusted even more precisely as engine load and speed change.

To ensure the E250 BlueTEC meets exhaust emission regulations in all 50 US states, the BlueTEC system uses selective catalytic reduction (SCR) with AdBlue injection. Newly accessibly through the fuel filler door, a water-based urea solution, AdBlue, is carried in its own small tank and metered into the exhaust in minute quantities, so the tank only needs to be refilled during routine scheduled maintenance. When AdBlue is injected into pre-cleaned exhaust gas, ammonia (NH₃₎ is released, converting nitrogen oxides into nitrogen and water in a downstream catalytic converter.

The latest Mercedes-Benz 4MATIC system is cleanly integrated into the 7-speed automatic transmission so it fits right into the standard body and utilizes the existing front suspension. Fuel efficiency has been improved, due to a number of innovative measures that minimize the energy needed to turn the extra gears and shafts. Mercedes-Benz expects an approximate 50/50 national installation rate between rear-wheel drive and 4MATIC on the E250 BlueTEC, keeping in mind northern States usually order and stock nearly 100% 4MATIC when available on passenger cars.

The new E250 BlueTEC sedan is the price-leader in the E-Class family, priced competitively at $51,400 while offering a clean diesel powertrain.

Aside from the E250 BlueTEC sedan, other 2014MY Mercedes-Benz US models with BlueTEC clean diesel include the GL350 BlueTEC 4MATIC (V6), ML350 BlueTEC 4MATIC (V6), and GLK250 BlueTEC 4MATIC.