Much before the current trend of downsizing engines with forced induction, Mercedes-Benz was one of the first European automakers which managed to implement downsized engines in its cars. The word Kompressor is synonymous with the brand, and for some reason Mercedes-Benz has managed to convince its customers to accept downsizing without much fuss – there are not many E-Class owners that fuss about how their big executive sedan is powered by a relatively small 1.8 litre engine – the M271.
The latest variation of the M271 is the new M271-EVO, and the word Kompressor has been dropped in favor of the new CGI brand name. CGI is part of the company’s new BlueEFFICIENCY strategy. In the C 250 CGI, it enables the car to consume just 7.2 to 7.9 litres per 100km on a combined cycle and is Euro 5 compliant.
The M271 CGI engine is available in various tunes – in the C 250 CGI it makes 204 horsepower and 310Nm of torque from as low as 2,000rpm. Fuel is injected via homogeneous or stoichiometric direct injection – Mercedes-Benz has studied our local fuel conditions and have disabled the fuel injection system’s ultra lean burn mode for the Malaysian spec cars. The injector used in direct injection can be tuned to inject extremely precise amounts of fuel as compared to conventional port injection which has a limit as to how much you can fine-tune it.
There’s also a lower tune in the C 200 CGI – which makes 184 horsepower and 270Nm of torque from just 1,800rpm. Looking the power figures, the small 1.8 litre in the C 200 CGI has the torque output of a 2.8 litre engine while the engine in the C 250 CGI has the torque output of a 3.2 litre engine!
And then of course there’s the turbo, which replaces the previous crank-driven supercharger. Modern turbocharger technology and tuning has eliminated the turbo lag that we used to be so used to back in the 90s. A turbocharger runs on exhaust gas and does not rob power from the engine, so your overall power increase is higher and more efficient. The engine does not have to be very big in displacement since the turbocharger forces more air into the engine compared with what the engine can normally suck in via its own cylinder vacuum.
It doesn’t stop here – the next step is the new DiesOtto engine concept, which allows a petrol engine to mimic the efficiency of the diesel combustion cycle even more. Mercedes-Benz’s DiesOtto is an attempt to perfect a special controlled auto ignition mode during low to medium engine speeds on low loads which ignites the air-fuel mixture through compression alone without spark ignition.
DiesOtto was featured in the F700 Concept
The DiesOtto will not be available in the market anytime soon, instead Daimler’s intention is to slowly add features from the DiesOtto concept to it’s production inline-4 engine one by one until the full concept is realised. When DiesOtto was unveiled in 2007, it was turbocharged, but at the time the M271 was still supercharged. Now, the M271 is turbocharged.
Direct injection and turbocharging are good ways to extract the maximum efficiency from a combustion engine and they have been mainstream on diesel engines for a long time. In Malaysia, the CGI engine is available in the C 200 CGI BlueEFFICIENCY, the C 250 CGI BlueEFFICIENCY, the E 200 CGI BlueEFFICIENCY, and the E 250 CGI BlueEFFICIENCY.
Find out more about CGI.