Geneva preview: First Merc direct injection engine debuts in CLS

Newswheel staff :: 25 February 2006 :: Filed under Four-door coupe, Mercedes Benz, Mercedes Benz CLS, Europe & UK, US

[Click on an image to view]

More power. Less guzzling. Fair dinkum

Better late than never. M-B has jumped on the petrol direct injection bandwagon. Of course, calling it plain old direct injection won’t do, so it’s stratified-charged gasoline injection, or CGI for short, in Mercedes-Benz parlance. Anyway, Merc’s first DI engine has been dropped into the slinky CLS four-door coupe just in time for next week’s Geneva shindig. And the good news is that it’s both more powerful and more fuel efficient than the engine it replaces. Cross your fingers, folks, we may yet escape creeping death by diesel…

As every good car junky knows, direct injection does exactly what it says on the tin. Instead of mixing fuel and air before pumping the whole shebang into the combustion chambers, direct injection motors spray neat fuel straight in. The trick is then to generate the sort of uniform and stable spray of fuel that results in efficient combustion. Get it right, and direct injection engines have the potential to spank conventional lumps for both fuel consumption and power output.

Merc’s new DI lump is a development of its existing quad-cam V6

Of course, you could say M-B is bringing up the rear on direct injection tech. Several car companies, both great and small, including the VW group, Ford, BMW, Mitsubishi, and oh, well, plenty of others already do DI engines. Needless to say, however, Merc’s grease monkeys reckon they’ve built a better example of the breed. To be known in the CLS as the 350 CGI, the new 3.5-litre DI V6 pummels its conventional, non-direct injection 350 counterpart to the tune of 20bhp with a 292bhp total. Torque is also up by a few twisty units to 269lb/ft.

Oh…the…Piezo-injector’s connected to the…Kraftsoffrail and…the…

However, before the smugness sets in at M-B’s Munich HQ, it’s worth noting that the DI engine is a little peakier – it requires 400rpm more to produce maximum power and 600rpm  extra for the full torque output. Still, we’re happy to doff our hats to any new engine that manages to deliver more power while using less fuel (in this case, consumption is down by around  around 10 per cent).

In most other regards, the new V6 is pretty similar to the boggo port-injected V6 on which it’s based. So, that’s variable valve timing on both inlet and exhaust cams, alloy block and head construction and a variable length inlet manifold, among other technical accoutrements. The 350 CGI will directly replace the existing 350 in the CLS range. No word as yet on whether a price premium will be attached, but we wouldn’t bet against it.