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.
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downsizing is the way of the future!
But somebody complaint about it…I wonder who…hmmm…
DiesOtto concept for petrol..i like it :)
me loike it!
I think that this engine will have lower HP and TorQue if it running in our country. Because of it direct injection, we can’t extract full power as our fuel quality is low.
They disabled the ‘lean burn’ mode for our market. That’s for high fuel efficiency. Otherwise there should not be any reason why hp and Torque should be capped. Never been a problem for other 4cyl direct injected turbos out there.
The report says, that Benz have ‘disabled the fuel injection system’s ultra lean burn mode’.
Without this ‘ultra lean burn mode’ the car will use slightly more petrol, but they will reach the torque and hp figures… ;)
‘Ultra lean burn mode’:
The air / fuel ratio of a ‘normal’ engine is 14.7 / 1. This is no secret, every rempit knows, that he has to change his carburettor jets after taking off the air filter. Otherwise the engine will be damaged by overheating.
This ‘CGI’ engine can run at a higher air / fuel ratio (more air / less fuel) if the petrol specs are okay. So if they decided to disable this ‘lean burn mode’, the engine will simply need slightly more petrol… ;)
Audi has been offering small 1.8L 4cyl turbo with direct injection for a number of years now so not sure what the fuss is all about with CGI
A bit saddened that they replaced the silky smooth 2.5 V6 engine in the C230 with the 1.8L cyl turbo and rebadged C250 CGI. The 4cyl will never be as smooth as the V6
i verily agree with u Diablo…V6 engines..should stay…the engines hv high efficiency….very smooth performance & high fuel savings & low maintenance….Sucking in too much of Air into the engine to cut petrol consumption (as in CGI engines)…..may not be a real saving as your engine may need regular services for the the overall engine would take a real beating…….
Hi Paul
Not sure if you are able to point out the differences of Merc’ CGIs with VWaudi’s TFSI ….
both seem quite similar, ie Turbocharged … wonder which ones more efficient though , as despite TFSI being synonymous with POWER, they aren’t exactly known for economy?
Appreciate if you could shed some light on this, cheers!
In modern era of 90’s GDI was synonym to Mitsubishi till the latest by Hyundai Theta II GDI engine. Nothing new but getting more efficient I suppose.
Yes, you’re right. “CGI” or “CDI” is not new technology.
The first production car with “petrol direct injection” was actually the Benz 300SL (W198) from 1955..
CDI is a marketing term used by Merc to denote it’s DIESEL common rail direct injection system.
GDI is a marketing term used by Mitsubishi sometime back to denote petrol direct injection and I don’t recall it being used with a turbo.
So not the same kind of fish to TFSI and CGI.
I’m guessing Merc’s CGI Blue Efficiency is focused more on efficiency especially by having a lean burn mode. This mode I assume is only turned on when there is no significant power requested (when accelerating). Perhaps lean burn mode only runs at part throttle cruising or on overrun etc.
Lean burn also implies non-stoichiometric(14.7:1) fuel air mixture which I suspect requires special emission control devices including special cat converter to neutralize the emissions. I speculate that this emission system cannot handle our fuel grade.
Maybe Paul can elaborate.
great new hi-tech engine, crappy old-fashioned 5spd gearbox. wud be better if merc fitted the 7spd auto frm their v6s and v8s
i drive a T210 (Avangarde 240)…nothing can beat this
Reasons for carbon formation inside inlet manifold in mercedes benz 200 cgi engines