Mercedes has suggested that the engine will be released with different power outputs later, and while Karsten Krebs, chief powertrain engineer, would not base himself on a realistic maximum power for the four-cylinder, he did tell Autocar that the three initial numbers are ” where we start,” suggesting that there is the potential for improved sports derivatives in the future.
Mercedes is still in the process of homologating the engine ahead of the CLA’s launch next year, and hasn’t yet provided expected MPG figures, but when asked for a hint, Krebs said “we have a feeling that with the hybrid powertrain you can achieve diesel levels in terms of fuel efficiency.”
The current CLA is officially rated at around 55mpg when equipped with a 2.0-litre diesel engine – and Autocar’s testers found it easy to achieve 60mpg+ at a cruise – and if the new M252 is anywhere near that comes, he could be one of the most efficient. petrol engines in its class.
The 27 hp EV motor can propel the car under its own power over short distances at speeds of up to 100 km/h, and draws its power from a 1.3 kWh 48V battery – also packed as tightly as possible – under the front passenger seat. Charging is done via recovery of up to 25 kW in the event of a delay.
By using the electric motor to start the engine, Mercedes could eliminate the need for a conventional starter motor, making the start-stop function “almost unnoticeable to the driver.”