Mercedes has stopped testing a Mercedes EQS equipped with a small petrol engine as a range extender. The solution was too expensive and didn’t bring major benefits.
A senior Daimler engineer told British magazine Autocar that Mercedes had been testing a Mercedes EQS prototype equipped with a small petrol engine that acts as a generator to charge the battery when it has run down and thus extend the range.
It seems that the small petrol engine was located at the front, probably on the single-engine EQS version. According to reports from colleagues at Autocar, Mercedes only built one prototype before abandoning the project.
The turbocharged engine had two cylinders derived from the 2-liter four-cylinder (M254), meaning it had a displacement of only 1 liter. It easily fits under the front bonnet of the single-engined version, as the Mercedes EQS had no frunk, and there was plenty of space. On the production version, the front hood didn’t even open.
Until the facelift unveiled last week, the Mercedes EQS had a range of up to 748 km in the EQS 450+ version with a 360 PS rear axle engine and a battery with a net capacity of 108.4 kWh. After the facelift, the new 118 kWh net capacity battery, which will be offered alongside the 108.4 kWh battery, promises a range of up to 822 km for the EQS 450+ version.
With the small 1-litre twin-turbo engine as a range extender, the version with the large 118 kWh battery could have achieved a range of over 1000 km. However, the range increase of around 20% would have needed a big financial and technical effort, which is not justified and would probably have interested a very small segment of customers. Prices of the Mercedes EQS are already very high, with the 450+ version starting at 109,551 euros. Sales are pretty weak, and Mercedes offers various promotions of optional packages to boost sales, so a more expensive range extender version wouldn’t stand much chance.
There have been electric range extender models in the car industry that have proved to be a failure.
In 2010, Audi developed an Audi A1 e-tron powered by a 60 PS (101 PS with boost) electric motor powered by a 12 kWh battery. The battery could be charged from the 220V socket or with a small 245 cc, 20 PS Wankel engine as a generator. The car remained a prototype and never reached the series production.
In 2013, BMW offered a range-extender version of the i3 that used a small two-cylinder motorcycle engine as a generator to charge the battery. In 2013, this solution made sense because the i3’s first battery had a capacity of only 18.8 kWh, giving it a range of only 150 km. That’s why BMW looked for a solution to increase range. BMW later abandoned this solution because it was 5,000 euros more expensive than the electric version and did not qualify for electric car subsidies.
Mazda currently offers the MX-30 in a range-extender version where an 830 cc, 75 PS Wankel engine works as a generator to charge the battery with a capacity of 17.8 kWh, half that of the all-electric version. The car is powered by a 170 PS electric motor.
Technically, the Audi A1 e-tron and BMW i3 Rex have proven that the solution of producing electricity on board and then consuming it is not viable due to energy losses.
