This week should have seen the start of the New York International Auto Show, but despite its postponement, many of the automakers who would have attended are still showing off their latest new-and-shiny projects online instead. Most of Mercedes-Benz’s headlines have come from its new electric EQS sedan and the humongous 56-inch-wide screen embedded in its dash. I don’t know about you, but I’m fast approaching burnout when it comes to huge screens in cars, so I’m far more interested in the details that Mercedes-AMG shared about its new performance hybrid system.
In 2014, Formula 1 racing adopted a new set of technical regulations as the sport moved from naturally aspirated 2.4 L V8 engines to hybrid powertrains that combine a 1.6 L V6 with a pair of hybrid systems to recover energy from waste heat as well as under braking. The Mercedes-AMG team came out of the starting blocks with a better hybrid powertrain than anyone else and dominated the sport from then on, racking up both the driver’s and constructor’s world championships that season and every year since.
I’ve repeatedly said that F1 technology almost never shows up in street cars, and endurance racing is the venue for real racetrack-to-road technology transfer. But in this case, Mercedes-AMG really is translating its F1 hybrid know-how into the brand’s street cars.
The first of Mercedes-AMG’s plug-in hybrid EVs will debut later this year. Unlike the PHEVs you can already buy from Mercedes-Benz, these will be optimized for performance, not efficiency. And the layout is also different from some of the luxury PHEVs we’ve seen so far, which either combine the electric motor with the transmission (BMW, Porsche) or drive one axle with the internal combustion engine and the other with an electric motor (Volvo).
The MGU-H makes it to a road car
Depending on the car, Mercedes-AMG will use either a 4.0 L twin-turbo V8 or a turbocharged 2.0 L inline four-cylinder that uses a version of the same electric turbocharger as the F1 race car and the forthcoming Project One hypercar. Known as an MGU-H (Motor Generator Unit Heat), the turbine can be spun up electrically, as opposed to just using exhaust gases. That makes it much more responsive than a traditional turbocharged engine, and Mercedes-AMG says that the system will maintain boost pressure electrically even when you take your foot off the accelerator or when you brake. Power output from the 2.0 L engine is a whopping 442 hp (330 kW).
The permanent magnet synchronous electric motor, which I note the company isn’t calling an MGU-K (Motor Generator Unit Kinetic) as in F1, is situated at the rear axle, integrated into a drive unit that also contains a two-speed transmission—like the Porsche Taycan and Audi e-tron GT—as well as the rear differential. Power and torque output will depend on the car, but the drive unit is capable of up to 201 hp (150 kW) and 236 lb-ft (320 Nm), which is sent to the rear wheels on top of whatever power and torque is being transmitted to them from the internal combustion engine via the nine-speed automatic transmission. But the electric motor is also capable of driving the car by itself at speeds of up to 81 mph (130 km/h).
Built for power, not efficiency
The 400 V battery pack is also directly informed by Mercedes-AMG’s F1 program. Most of the time, an EV’s battery is optimized for energy density, as the market has apparently decided that range efficiency is the only metric worth caring about. Not here—Mercedes AMG says its focus was on delivering high power, frequently, together with low weight (which equals high power density), as well as fast energy absorption.
It’s a highly compact battery, consisting of 560 cylindrical 2170 cells, each permanently surrounded by a non-conductive cooling liquid that is actively circulated through the battery and a low-temperature radiator. This way, the battery is kept at its optimum temperature, a constant 113˚ F (45˚ C).
The entire pack weighs 196 lbs (88 kg), with a total capacity of 6.1 kWh. It’s able to output a constant 94 hp (70 kW) with bursts of up to 201 hp (150 kW), which gives it a rather good power density of 1 hp/lb (or 1.7 kW/kg in real units). The battery can also capture regenerated energy from the rear electric motor at up to 90 kW, although when used on track in Race Mode, it will default to the standard (lower) setting, as Mercedes-AMG recognizes that track drivers want to use their brakes.
The end result will be some impressively quick cars. Total power output for the 2.0 L hybrid should be 643 hp (480 kW), with the V8 hybrid capable of a massive 804 hp (600kW) and 738 lb-ft (1,000 Nm), which Mercedes-AMG says should translate to sub-3-second 0-60 times.
Listing image by Mercedes-AMG