Innovative drive technology with electric exhaust gas turbocharger for a highly agile driving experience
Affalterbach. With technology derived directly from Formula 1, the latest generation of the Mercedes‑AMG C 43 4MATIC sets new standards for innovative drive solutions both as a Saloon (combined fuel consumption 9.1-8.7 l/100 km, combined CO2 emissions 206-196 g/km) and as an Estate (combined fuel consumption 9.2-8.8 l/100km, combined CO2 emissions 209-199 g/km). Following its premiere inthe Mercedes-AMG SL 43, the AMG 2.0-litre four-cylinder engine, the world’s first series-production unit to feature an electric exhaust gas turbocharger, is now also being used in the C-Class. The new form of turbocharging guarantees particularly spontaneous response across the entire rev range and thus offers an even more dynamic driving experience. The turbocharger is operated via the 48-volt electrical system, which also feeds the belt-driven starter-generator (RSG). In the Mercedes-AMG C 43 4MATIC the unit produces 300 kW (408 hp) and, in certain driving situations, is able to call upon a brief additional boost of 10 kW (14 hp) from the RSG. The standard rear-axle steering, the AMG Performance 4MATIC permanent all-wheel drive with rear-biased torque distribution, the AMG SPEEDSHIFT MCT 9G transmission with wet start-off clutch and the AMG RIDE CONTROL suspension with Adaptive Damping System also contribute to the dynamic driving experience. In keeping with this, brand-specific features in the equipment and appointments as well as in the exterior and interior design emphasise the performance-oriented character of the new Mercedes-AMG C 43 4MATIC.
“The C-Class has always been an absolute success story for Mercedes-AMG. With the innovative technology of the electric exhaust gas turbocharger, we are once again significantly increasing the attractiveness of this latest generation. The new turbocharging system and the 48-volt on-board electrical system not only contribute to the outstanding driving dynamics of the C 43 4MATIC, but also improve its efficiency. In this way, we are demonstrating the tremendous potential that lies in electrified combustion engines. The standard all-wheel drive, the active rear-axle steering and the quick-shifting transmission all serve to enhance the Driving Performance that is the hallmark of AMG”, says Philipp Schiemer, Chairman of the Board of Management of Mercedes‑AMG GmbH.
At the heart of the new Mercedes-AMG C 43 4MATIC is the AMG 2.0-litre four-cylinder engine, which combines innovative technologies and high performance with exemplary efficiency. At the same time, it remains true to a tradition typical of the brand: not only was it developed entirely at the company’s site in Affalterbach, but it is also manufactured there in accordance with the principle of “One Man, One Engine”. In this process, Mercedes-AMG combines the craftsmanship of its highly qualified employees with the latest production methods of Industry 4.0 and a high degree of digitalisation.
The internally named M139l engine (l for longitudinal installation) is the world’s first series-production engine to be turbocharged with an electric exhaust gas turbocharger. The innovative system is a direct derivative of the technology that the Mercedes-AMG Petronas F1 Team has been using so successfully in the premier class of motorsport for many years. The new form of turbocharging guarantees particularly spontaneous response across the entire rev range. This leads to an even more dynamic driving experience, while at the same time increasing efficiency.
The functional principle of the electric exhaust gas turbocharger in detail
An electric motor around four centimetres thin is integrated directly on the turbocharger shaft between the turbine wheel on the exhaust side and the compressor wheel on the intake side. Electronically controlled, this drives the shaft of the turbocharger directly and thus accelerates the compressor wheel, before the exhaust gas flow takes over the drive in the conventional way.
This significantly improves the response directly from idle speed and across the entire rev range. The combustion engine responds even more spontaneously to accelerator pedal input, while the entire driving feel is significantly more dynamic. In addition, the electrification of the turbocharger enables higher torque at low revs. This also increases agility and optimises acceleration from a standstill. Even when the driver takes his foot off the accelerator or brakes, the technology is able to maintain boost pressure at all times, so ensuring a continuously direct response.
Powered by the 48-volt on-board electrical system, the electric exhaust gas turbocharger operates at speeds of up to 175,000 rpm, which enables a very high air flow rate. The turbocharger, electric motor and power electronics are connected to the combustion engine’s cooling circuit to create an optimal temperature environment at all times.
The closed-deck design of the M139 – adopted from the world of motorsport – ensures maximum rigidity in conjunction with low weight and allows peak combustion pressures of up to 160 bar. The areas around the cylinders are mostly solid, and the cover plate is penetrated only by smaller ducts for the coolant and engine oil. Other design highlights of the engine include NANOSLIDE technology, with which the linings are coated so as to reduce the friction between piston and cylinder. This gives the linings a mirror-like surface for minimal friction, is twice as hard as conventional grey cast-iron liners and therefore makes them much more durable. The coating made its debut in the AMG V8 engine M156, has been used to refine other AMG engines for many years and can also be found in the Formula 1™ engine of the Mercedes-AMG Petronas Formula 1 Team.
Another outstanding feature is the two-stage petrol injection. In the first stage, particularly fast and precise piezo injectors deliver the fuel into the combustion chambers at pressures of up to 200 bar. The second stage adds intake manifold duct injection with solenoid valves, which is needed to achieve the engine’s high specific power output.
The high output also necessitates a sophisticated cooling system that can cool the cylinder head and crankcase to different temperature levels. This measure makes it possible to maintain a cold cylinder head for maximum power with efficient ignition timing, along with a warm crankcase to reduce internal engine friction. The cylinder head is cooled by a mechanical high-performance water pump; the crankcase is cooled by a second, electrically driven water pump. After a cold start, this pump remains passive until the engine has warmed up. In operation it is regulated by the engine control unit so that the crankcase is always cooled according to need.
300 kW (408 hp) and 500 Nm enable sporty driving performance
In the 2.0-litre four-cylinder in-line engine, innovative technology helps the Mercedes-AMG C 43 4MATIC to achieve a rated output of 300 kW (408 hp) at 6750 rpm. The maximum torque of 500 Nm is available at 5000 rpm. Depending on the situation, the system also briefly provides an additional boost of 10 kW (14 hp) through the belt-driven starter generator (RSG). The second-generation RSG acts as a mild hybrid, providing this temporary power boost as well as functions such as gliding and recuperation for maximum efficiency. At the same time, the 48-volt technology also increases comfort, as the transitions between the start-stop function and the gliding mode function are almost imperceptible.
The C 43 4MATIC Saloon accelerates from a standstill to 100 km/h in just 4.6 seconds, while the C 43 Estate takes only slightly longer for the same exercise, at 4.7 seconds. The top speed is electronically limited at 250 km/h in both models. By adding the optional AMG Driver’s Package, it can be raised to 265 km/h in each case. The great efficiency potential of the innovative turbo technology is revealed by the combined consumption figures according to WLTP of 9.1-8.7 l/100 km for the Saloon and 9.2-8.8 l/100 km for the Estate.
AMG SPEEDSHIFT MCT 9G transmission with wet start-off clutch and AMG Performance 4MATIC
Power is transmitted via the AMG SPEEDSHIFT MCT 9G transmission (MCT = Multi-Clutch Transmission), in which a wet start-off clutch replaces the torque converter. It reduces weight and, thanks to its lower inertia, optimises response to accelerator pedal input, especially during spurts and load changes. The elaborately calibrated software ensures extremely short shift times as well as fast multiple downshifts if required. In addition, the intermediate throttle function in the “Sport” and “Sport+” driving modes delivers a particularly emotionally appealing gearshift experience. There is also the RACE START function, which ensures optimal acceleration from a standstill. The ECO start/stop function is automatically activated in the “Comfort” drive program; the “Glide” function can be activated in “Individual”.
The AMG Performance 4MATIC permanent all-wheel drive features an AMG-specific torque distribution between the front and rear axles of 31 to 69 percent. The rear-biased configuration provides for enhanced dynamic handling, including higher lateral acceleration and improved traction when accelerating.
AMG DYNAMICS standard component of the AMG DYNAMIC SELECT drive program selection
The five AMG DYNAMIC SELECT drive programs “Slippery”, “Comfort”, “Sport”, “Sport +” and “Individual” permit a wide range of vehicle characteristics, from comfortable to dynamic. The distinct driving modes offer an individual driving experience, precisely tailored to different driving conditions. In the “Sport” and “Sport+” programs, the engine’s responsiveness, the transmission’s shifting behaviour and the suspension and steering are tuned to be particularly agile.
The C 43 4MATIC also features the integrated “AMG DYNAMICS” driving dynamic control system as a component of the AMG DYNAMIC SELECT drive programs. This enhances the stabilising functions of the Electronic Stability Program ESP® with interventions to add agility to the steering characteristics and additional ESP® functions. When cornering at speed, for example, brief braking intervention at the inner rear wheel generates a defined yawing moment around the vertical axis for responsive and precise turn-in.
The extent and effectiveness of these interventions depend on the AMG DYNAMIC SELECT program selected, whereby drivers using “Individual” mode can determine the settings for the AMG DYNAMICS levels “Basic”, “Advanced” and “Pro” for themselves. The ESP® can be adjusted in three stages. “On” is the standard selection that offers high safety, adapted to the sporty character of the overall vehicle. “Sport”, on the other hand, allows higher drift angles, while “Off” allows the system to be switched off completely for a particularly sporty driving style on closed-off race tracks.
AMG RIDE CONTROL suspension with Adaptive Damping System
The AMG RIDE CONTROL steel-spring suspension with Adaptive Damping System, which is standard on the C 43 4MATIC, combines decidedly sporty driving dynamics with the long-distance comfort typical of the brand. The basis for this is provided by the front axle, with specially developed steering knuckles and suspension joints on the spring control arm, and by the rear axle, which also features elastokinematics designed for driving dynamics. Complementing this, the Adaptive Damping System continuously adapts the damping at each individual wheel to the current demand – always taking into account the preselected suspension level, the driving style and the condition of the road surface. In addition to an improvement in ride quality and comfort, this leads, above all, to an increase in driving safety. There is a choice of three different damping maps (“Comfort”, “Sport” and “Sport+”).
Three-stage AMG parameter steering and standard rear-axle steering
The steering layout of the C 43 4MATIC contributes to the improvement in both dynamics and comfort. The three-stage AMG parameter steering system, for example, features a variable steering geometry ratio that adapts to the selected drive program. At high speeds, the steering power assistance decreases; at low speeds it is steadily increased. As a result, comparatively little steering effort is required at low speeds, as well as when manoeuvring and parking, while the best possible control over the vehicle is maintained when driving faster. In the “Sport” and “Sport+” suspension settings, the driver also experiences significantly more feedback about the driving condition via the steering wheel.
The new Mercedes-AMG C 43 4MATIC brings rear-axle steering to the best-selling model series from Affalterbach as standard. It operates with a maximum steering angle of 2.5 degrees. Up to this point, the rear wheels turn in the opposite direction to the front wheels at speeds of up to 100 km/h (variable depending on the AMG DYNAMICS setting). This leads to a virtual shortening of the wheelbase, which in turn results in significantly more agile turn-in, less steering effort and improved manoeuvrability. For example, the turning circle is noticeably reduced when turning or parking. At speeds above 100 km/h (variable depending on the AMG DYNAMICS setting), on the other hand, the rear wheels turn in parallel to the front wheels – up to a maximum of 0.7 degrees. This virtual extension of the wheelbase has a positive effect on driving stability, leads to a faster build-up of lateral force when changing direction and thus to a more direct reaction of the vehicle to steering commands. The response of the rear-axle steering depends on the selected AMG DYNAMIC SELECT drive program.
AMG sports braking system and AMG exhaust system with sporty engine sound
The AMG sports braking system with silver-painted brake callipers and black “AMG” lettering guarantees outstanding deceleration values and optimum control. On the C 43 4MATIC, internally ventilated and perforated brake discs measuring 370 x 36 millimetres with 4-piston fixed callipers are fitted at the front axle, and discs measuring 320 x 24 millimetres with 1-piston floating callipers at the rear.
The AMG exhaust system with its sporty engine sound provides the appropriate acoustic background. Depending on the drive program selected, the noise level ranges from balanced and discreet to emotionally sporty. The sound characteristics are controlled via an exhaust gas flap, depending on engine speed and load. For the occupants, the listening pleasure can be further enhanced by the addition of the option AMG Real Performance Sound. The actual engine sound is picked up by a sensor in the exhaust system and fed into the interior for a particularly emotive sound experience.
Characteristic AMG elements for the exterior and interior ensure a sporty, refined appearance
Outside as well as inside, numerous AMG-specific details underscore both the dynamic and the luxurious character of the C 43 4MATIC. In terms of exterior design, these include the AMG-specific radiator grille with vertical struts in chrome, the AMG front apron with flics, sporty air intakes and chrome-plated trim element, the matching side sill panels, the diffuser-look rear apron and the two round twin-tailpipe trim elements. The C 43 4MATIC is fitted with AMG light-alloy wheels and 18-inch tyres as standard, with 19- and 20-inch tyres available as options.
In the interior, such features as AMG seats with a distinctive upholstery layout and seat covers in ARTICO man-made leather/MICROCUT microfibre in black with red contrasting stitching and red seat belts provide a particularly sporty touch. Further options include leather and nappa leather seat covers. Added to this is the AMG Performance steering wheel in nappa leather, with flattened bottom section, perforated in the grip area and with silver-coloured aluminium gearshift paddles. The two round AMG steering wheel buttons allow fast and unerring operation of various dynamic driving functions and of the AMG DYNAMIC SELECT drive programs. The instrument panel and the beltlines are upholstered in ARTICO man-made leather with red topstitching. The sporty-luxurious atmosphere is rounded off by AMG sports pedals, AMG floor mats and illuminated door sill trims with AMG lettering.
The MBUX infotainment system includes various AMG-specific displays and functions. These include special displays in the instrument cluster, in the portrait-format multimedia central display in the centre console and in the optional head-up display. Added to this is the shortcut button for the AMG DYNAMIC SELECT drive programs. AMG TRACK PACE, the data logger for use on the race track, is also integrated. The software records more than 80 vehicle-specific data such as speed, acceleration, steering angle and brake pedal actuation ten times per second while the car is being driving around a race track. In addition, there is a display of lap and sector times as well as additional training and analysis tools.