Mercedes-AMG has revealed the new 2.0-litre M139 engine, which for now will be the world’s most powerful four-cylinder production engine.
The hand-built M139 will be available in two states of tune with the highest output produced in the S-model which offers 310kW and 500Nm, the latter available from 5000-5250rpm.
AMG will also produce a basic version that develops 285kW and 480Nm. Peak torque is accessible from 4750-5000rpm. For comparison, that’s a 30kW bump over the previous M133 engine.
Engineers claim the engine’s configuration delivers power similar to that of a naturally aspirated unit. The increasing torque at higher rpm allows the engine to be more free-revving, it will run to a 7200rpm redline.
One of the key design features of the new engine is the fact that it is rotated around on the vertical axis by 180 degrees. This means the turbochargers and exhaust manifold are located at the rear and the intake system is at the front.
Engineers have gone with this setup as testing demonstrated that it allows for the flattest possible and aerodynamically advantageous front section design. The rearrangement also allows for improved air ducting with shorter distances and fewer diversion for both the intake and exhaust side.
Other technical wizardry includes the linings of the pistons and cylinders being coated in patented Nanoslide technology to reduce friction. The result is a mirror-like surface allowing for minimal friction as well as a more durable surface which is claimed to be twice as hard as conventional grey cast-iron liners.
The M139 also has much larger exhaust valves compared to the M133 engine. The injection nozzles and spark plug system in the cylinder head have been repositioned and slightly angled to accommodate the new set up. The larger exhaust cross-sections allow the gases to stream out of the combustion chamber with low losses, reducing the overall piston venting action.
For the best of both worlds, turbocharging and direct injection with a spray-guided combustion process has been used which offers a high power yield, improved thermodynamic efficiency and therefore reduced fuel consumption and exhaust emission.
This is the first application of the two-stage fuel injection for the new high-performance four-cylinder. The first stage sees the piezo injectors supply fuel to the combustion chamber at a pressure of up to 200 bar whilst in the second stage there is additional intake manifold injection via solenoid valves.
"With the M139, we have once again impressively demonstrated the engine expertise of Mercedes-AMG. Not only is the output per litre unrivalled for a turbocharged engine, the high level of efficiency also demonstrates that the internal combustion engine still has further potential," says Tobias Moers, Chairman of Mercedes-AMG GmbH.
The M139 is assembled on an all-new newly production line at the AMG facility in Affalterbach, it will make its debut in the new-generation AMG A45 hot hatch.
Mercedes-AMG 2.0-litre M139 turbo engine specs:
Displacement: 1991cc
Power: 310kW at 6750rpm (AMG S) or 285kW at 4750rpm (basic version)
Torque: 500Nm at 5000rpm (AMG S) or 480Nm at 4750rpm (basic)
Redline: 7200rpm
Compression ratio: 9.0:1
Bore x stroke: 83.0 x 92.0mm
Max charge pressure: 2.1 bar (S), 1.9 bar (standard)
Engine weight (wet): 160.5kg
Turbocharger: Single twin-scroll with roller-bearing compressor and turbine wheels
Mixture formation: Third-generation combined direct and manifold injection
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