The AMG division of the German car manufacturer Mercedes-Benz has developed the worlds most powerful 2.0-litre four-cylinder production engine. The engine has been revealed by Mercedes-AMG and will feature in the upcoming A 45, CLA 45 and GLA 45 production series cars.
The M139 engine which comes with a maximum displacement of 2.0-litre, produces 387 Hp of power and 480 Nm of torque in the standard model and the ‘S’ variant produces 421 HP of power and 500 Nm of torque. The previous M133 engine produced 360/381 Hp of power and the torque curve resembled like a diesel engine. The new engine rather than flat-lining from 2000 RPM produces a strong surge and gives a sporty power delivery.
The engine is completely a new design and is made with lighter materials and a robust cylinder block which has a strengthening skirt around the cylinders. The engine produces a 160 bar combustion pressure and all the diesel-like engine reinforcement is required to withstand this pressure.
The 16-valve cylinder head is also new and disperses the heat efficiently. The cylinder head gets a separate coolant plumbing, a redesigned water jacket, oil, liquid and air cooling for the turbo to keep the temperatures low. The exhaust valves and valve seats are also larger and the cylinder head features, ‘Camtronic’ variable valve system, which has two cam profiles and refines the inlet and exhaust valve control, for performance as well as fuel efficiency. The head also gets dual injectors per cylinder, as a single injector will be at its upper limit, in terms of delivering the fuel volume, required under hard acceleration.
The turbocharger runs on low-friction bearings and gets an electric waste gate to minimise loss of boost. The cylinder head has been rotated 180-degrees and the turbo now sits in between the engine and the bulkhead requiring more temperature control features. The extra cooling for the turbo is provided by a direct fan airflow and electric water pumps which can remain On even after the engine has been turned Off. This feature helps cool the engine, cylinder head and the turbo. Also, the ‘S’ version uses the air-conditioner to cool off the engine in certain situations.
The assembly line used for the AMG engines is streamlined to save time by using electronically sequenced power tools which can be programmed to set the torques as the assembly goes further and each engine is still hand built under the company policy of ‘One Man, One Engine’.