Following two variants with V8 engines, Mercedes-AMG is presenting the entry-level SL 43 model of its newly developed roadster icon. The SL 43 options an M139 in-line two-liter, four-cylinder gasoline engine with an electrical exhaust fuel turbocharger—used for the primary time in a manufacturing car.
This know-how comes from Formulation 1. The system within the SL 43 is a direct spinoff of the event efficiently utilized by the Mercedes-AMG Petronas F1 Crew for a few years within the premier class of motorsport. The brand new type of turbocharging delivers notably spontaneous throttle response throughout all the rev vary, thereby providing an much more dynamic driving expertise whereas growing effectivity on the similar time.
The turbocharger is operated by way of the 48-volt electrical system, which additionally feeds the belt-driven starter-generator (RSG). Consequently, the Mercedes-AMG SL 43 has a rated output of 280 kW (381 hp) at 6750 rpm and a most torque of 480 N·m obtainable between 3250 rpm and 5000 rpm. A further short-term increase of 10 kW (14 hp) from the RSG in obtainable in sure driving conditions.
In its lengthy historical past, the SL has repeatedly set technological milestones. For instance, whereas the legendary 300 SL Gullwing in 1954 was the world’s first series-produced passenger automotive with direct petrol injection, the brand new Mercedes-AMG SL 43 is now the very first series-produced car with an electrical exhaust fuel turbocharger. With this know-how, the SL additionally has an impressive efficiency vary in its entry-level model. Which means our seemingly smallest SL combines the standard AMG Driving Efficiency with luxurious and luxury on the absolute high stage. What’s extra, with this progressive engine we’re undoubtedly additionally interesting to a wider clientèle.
—Philipp Schiemer, Chairman of the Board of Administration of Mercedes‑AMG GmbH
The electrical exhaust fuel turbocharger is an interesting instance of the intensive switch between Formulation 1 know-how and the event of manufacturing automobiles. In implementing this together with our highly effective M139 four-cylinder, we have been additionally ready to attract on the big wealth of expertise of our colleagues at Mercedes-AMG Excessive Efficiency Powertrains. The know-how will increase agility and thus driving enjoyable, whereas on the similar time enhancing the effectivity of the drive system. We’re pursuing bold objectives with a view to our electrified future. Revolutionary elements reminiscent of the electrical exhaust fuel turbocharger assist us to realize this.
—Jochen Hermann, Chief Technical Officer of Mercedes‑AMG GmbH
The working precept of the electrical exhaust fuel turbocharger is predicated on the identical know-how utilized by the Mercedes-AMG Petronas F1 Crew. An electrical motor round 4 centimeters skinny is built-in straight on the turbocharger shaft between the turbine wheel on the exhaust aspect and the compressor wheel on the consumption aspect. Electronically managed, this drives the shaft of the turbocharger straight and thus accelerates the compressor wheel earlier than the exhaust fuel stream begins to drive it conventionally.
This considerably improves rapid response from idle velocity and throughout all the engine velocity vary. The combustion engine responds much more spontaneously to accelerator pedal enter, whereas the general driving expertise is extra dynamic.
As well as, the electrification of the turbocharger permits greater torque at low revs. This additionally will increase agility and optimizes acceleration from a standstill. Even when the driving force takes their foot off the accelerator or applies the brakes, the know-how of the electrical turbocharger is ready to keep the increase stress always. This ensures so {that a} steady rapid response.
The turbocharger works at speeds of as much as 170,000 rpm, which permits a really excessive airflow fee. The turbocharger, electrical motor and energy electronics are related to the combustion engine’s cooling circuit to create an optimum temperature setting always.
The second-generation RSG additionally capabilities as a light hybrid within the 48-volt on-board electrical system, which along with the short-term energy increase permits capabilities reminiscent of gliding mode and power restoration for max effectivity. On the similar time, the 48-volt know-how additionally will increase consolation, because the transitions between the start-stop operate and the gliding mode operate are virtually imperceptible.
The M139 engine, which has lengthy been used transversely in Mercedes‑AMG compact fashions with out an electrical exhaust turbocharger, is positioned longitudinally within the SL 43. Within the entry-level mannequin within the SL collection, which all the time options rear-wheel drive, it’s also mixed with the AMG SPEEDSHIFT MCT 9G transmission (MCT = Multi-Clutch Transmission) for the primary time.
A moist start-off clutch replaces the torque converter. It reduces weight and, because of its decrease inertia, optimizes response to accelerator pedal enter, particularly throughout spurts and cargo modifications. The elaborately calibrated software program ensures extraordinarily brief shift occasions in addition to quick a number of downshifts if required.
From a standstill, the SL 43 accelerates to 100 km/h in 4.9 seconds if required, and the highest velocity is 275 km/h. Along with the efficiency it affords, the entry-level mannequin of the collection can be distinguished by comparatively low consumption and emission figures: mixed gasoline consumption 9.4-8.9 l/100 km (25-26.4 mpg US), mixed CO2 emissions 214-201 g/km.
