Mercedes AMG has developed a four-cylinder turbocharged engine in series production - Mercedes-AMG 2.0-litre M 139 that puts out up to 421 hp power and 500 Nm torque. With this, Mercedes AMG has raised its performance bar over its previously powerful M133 engine by 41 hp power and 25 Nm torque. The new power-packed engine will be manufactured on ‘One Man, One Engine’ principle at the company’s production line in Affalterbach.
AMG has set up a completely newly-designed production line engine manufactory in Affalterbach, where the new engine is assembled entirely by hand. The ‘One Man, One Engine’ principle of Mercedes-AMG blends together Industry 4.0 methods, while incorporating factors like ergonomics, quality assurance, material handling, sustainability and of course efficiency for maximum flexibility and transparency while using digital technologies.
The new four-cylinder engine will be available in two output versions for better performance from Mercedes-AMG cars - S model and basic version, with 421 hp and 387 hp power respectively. The peak torque of 500 Nm is available in a range of 5,000-5,250 rpm, whereas 480 Nm for the basic version will be available at 4,750-5,000 rpm.
The new engine boasts of a host of intelligent design features. The new Mercedes-AMG M 139 is rotated around its vertical axis by 180 degrees, likewise transversely installed M133 engine, which effectively means that the turbocharger and exhaust manifold are now positioned at the rear, whereas the intake system is positioned at the front. The configuration allows aerodynamically advantageous front section design and improved air ducting with shorter distances and fewer diversions - both on the intake and exhaust side.
The all-aluminium crankcase is a chill-cast unit developed using gravity pouring technique for high strength. The crank assembly with a lightweight, forged steel crankshaft and forged aluminium pistons with optimised piston rings combines low friction with high strength. And to reduce friction between the pistons and cylinders, the cylinder linings are coated using the patented NANOSLIDE technology that gives the linings a surface that is twice as hard as conventional grey cast-iron liners and therefore makes them much more durable. The coating was first used for AMG's M 156 engine and has further benefitted AMG engines for many years and can also be found in the Formula 1 engine of Mercedes AMG Petronas Motorsport, the company noted.
Injection nozzles and spark plug system in the cylinder head have been repositioned that made it possible to greatly enlarge the exhaust valves as compared to those of the preceding M 133 engine. The larger exhaust cross-sections allow the gases to stream out of the combustion chambers with low losses, and reduce the overall piston venting action.
The new high-performance four-cylinder has been introduced with a two-stage fuel injection. In the first stage, the precisely operating piezo injectors supply fuel to the combustion chambers at a pressure of up to 200 bar and is controlled by the engine management system as required. In the second stage, there is additional intake manifold injection using solenoid valves. This is needed to achieve the engine’s high specific output. Turbocharging and direct injection with a spray guided combustion process not only allows a high power yield, but also improves thermodynamic efficiency that cuts down on fuel consumption and exhaust emissions.
The new twinscroll turbocharger combines optimum responsiveness with a high power in the upper rpm range even at low engine speeds. In addition to this, the turbine housing is divided into two flow passages, which run parallel to one another. Together with the likewise divided ducts in the exhaust manifold, this makes it possible to feed the exhaust flow to the turbine separately. The setup prevents individual cylinders from influencing each other negatively during load cycles, and to improve the gas cycle, claims the company. The engineers have also introduced roller bearings in the shafts of the compressor and turbine that reduce mechanical friction within the turbocharger to a minimum, thereby allowing the charger to respond more readily and reach its maximum speed of up to 1,69,000 rpm more rapidly.
Using Cooling System for Increased Power
The coolant flow through the radiators is assisted by a high-performance electric pump together with the intercooler connected in series. This provides ideal cooling of the highly compressed charge air, thereby contributing towards optimum engine performance. Cooling of the transmission oil is integrated into the engine's coolant circuit, and is assisted by a heat exchanger mounted directly on the transmission.
The demand-controlled, electric high-performance water pump operates independently of the engine speed. Late activation during warm-up means that the engine block warms up more rapidly, with a positive effect on friction, consumption and emissions. The pump can also be switched on or off as required when driving under less power or at low engine speeds. Furthermore, the electric water pump ensures the full engine output and optimum heat dissipation over the entire engine speed range. It also protects against thermal damage when idling in high ambient temperatures.
Mercedes-AMG engineers also reduced the number of test stations by grouping several individual stations into three central stations - drag torque test, leakage test for oil/coolant and fuel systems as well as for complete engine water jacket. All parameters and measured values at the new assembly are digitally recorded and stored so that the process of each individual engine can be tracked. This results in considerable time saving as well as higher efficiency with the new engine.