Mercedes Concept CLA Has EV/Combustion Flexibility Built In

As with the Stellantis STLA Frame announcement, Mercedes-Benz is previewing a flexible new vehicle architecture designed to work with both electric and combustion drivetrains. Carmakers are scrambling to hedge the timing of the industry’s shift to battery-electric vehicles in the face of high prices and the immature DC fast-charging network.

The Mercedes-Benz Modular Architecture (MMA) underpins the company’s Concept CLA-Class compact EV with an 800-volt electric architecture managed by a silicon carbide inverter to power a 200-kilowatt (272 horsepower) electric drive unit on the rear axle in standard configuration and an additional 80-kW (109 hp) front drive module to provide optional 4Matic all-wheel drive.

Both electric motors are permanent magnet type, and the rear-mounted drive unit incorporates a planetary two-speed transmission (like a Ford Model T!) with 11:1 low gear and 5:1 high gear. The front is the conventional single-speed device with a disconnect clutch to separate the motor from the wheels for improved efficiency when driving on the rear motor alone.

Modularity in the MMA name also refers to the battery packs. The 58 kilowatt-hour standard pack will employ lithium-iron-phosphate (LFP) chemistry and the premium 85-kWh pack uses nickel-manganese-cobalt (NMC) chemistry. The cells in both cases are prismatic, with each of the pack’s four modules packing 48 cells.

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Mercedes lists the comparative energy density for each chemistry in terms of watt-hours per liter of volume. The NMC battery contains 680 Wh/l, while the LFP carries 450 Wh/l. Either way, the packs are the same size and they are close in weight, with the NMC pack weighing 496 kg (1,091 lbs.) and the LFP tipping the scales at 484 kg (1,065 lbs.).

The bare battery-electric CLA Class platform reveals its high-voltage battery pack in the floor, front and rear electric drive units, and the on-board charger mounted just ahead of the rear wheels (right). MERCEDES-BENZ

Mercedes says the Concept CLA can travel 466 miles on a charge using the premium pack. No range was provided for the standard LFP battery. The premium battery can charge at 320 kW at DC fast charging stations, adding as much as 36 kWh in ten minutes. Again, no specs were provided for the standard LFP battery. Top speed is 130 mph.

Alternatively, drivers will be able to choose a combustion-powered version the CLA. It is powered by a 1.5-liter Miller-cycle four-cylinder engine (code name M 252) that the company says is part of its new Family of Modular Engines (FAME). The fundamental characteristics of the FAME engines include an aluminum engine block with Mercedes’ Nanoslide cylinder liner technology. It has a partially integrated exhaust manifold with segmented-turbine turbocharger.

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It is supplemented by a 20-kW (27 hp) 48-volt mild hybrid electric motor that is embedded in the 8-speed dual-clutch transmission. It is powered by a 1.3-kWh lithium-ion battery that lets the electric motor supplement the combustion engine’s torque at low speeds. Total system peak power is 140 kW (190 hp).

The 48-volt power also runs the air conditioning compressor, so it can run when the car is stationary and the engine has stopped. Current Mercedes four-cylinder combustion drivetrains are not as refined as the brand would lead you to expect, so it is welcome news to hear that the company has placed additional emphasis on isolating the engine’s noise, vibration, and harshness from the CLA’s occupants.

The combustion-powered CLA Class has optional all-wheel drive that is powered by a driveshaft from the front transaxle to a differential on the rear axle. MERCEDES-BENZ

Mercedes says that the car incorporates a comprehensive package of foams and covers under the hood to muffle noise at the source. Additionally, they’re using a double bulkhead that is employed on the company’s higher-end models to the A-pillar and floor areas, to block out any sound escaping the engine bay.

The company did not announce a timetable for the arrival of production models based on the Concept CLA-Class.