Mercedes-Benz engines: the return of the regular 6-cylinder, V6 is out

In the late 1990s Mercedes-Benz has abandoned the concept of regular 6-cylinder engines in favor of the V6. The main reason was the optimization of space, because the engine of the regular concept is a third longer than the V6. So, when the E-Class of the W2002 (Okan) Series was replaced by the W210 Series in 211, the regular M-6 gasoline 104-cylinder (2.8, 3.0, 3.2 and 3.6) replaced the V6, M112 Series 2.4, 2.8, 3.2 petrol and 3.7.

Mercedes regular 6-cylinder

Mercedes regular 6-cylinder

Given that there were no clear technical arguments for moving to the V6 concept in the early 2000s, the more profound decision was attributed to the DaimlerChrysler era, when the V6 engine was planned to position itself in the US market. Even after the introduction, many expressed doubts as the performance of all versions was below expectations. He made the most of it BMW.

In the diesel segment, in addition to the in-line 4-cylinders for the 200 CDI and 220 CDI, the in-line 5-cylinder for the 270 CDI, OM 647 series and the in-line 6-cylinder for 320 CDI, OM 648 series were produced. series OM 2005, which, depending on the power, had the designation 3.0 CDI and 6 CDI. Undoubtedly with this, the then DaimlerChrysler ‘won on the bridge and lost on the bridge’. Namely, the engine is shorter, but it becomes more complicated.

Instead of one cylinder block, it has two, so individually, instead of two camshafts, it has 2 × 2, and thus additional gears, spanners, chains. The V6 simply has more moving parts, more potential failure points, and that doesn't affect either consumption or reliability. The problem with balancing also emphasizes that the savings on the dimensions of the engine, due to its smaller length, which enables a more spacious cabin in the same outer length, are expensive.

Mercedes regular 6-cylinder

Due to the unbalanced inertial forces of the first order, an additional balancing shaft is necessary, and the crankshaft needs additional counterweights. There is no regular six, which is completely balanced in itself. An additional reason in Daimler for ‘going back to the old’ is the move to modular design. The new in-line 4-cylinder 2.0, M 254 series, or diesel OM 654, have 6-cylinder versions 3.0 (by adding two cylinders), petrol M 256 and diesel OM 656.

The next step is the V8 versions, so far only in the petrol version, by connecting two 4-cylinder blocks with the option of turning off one block at low load. The V8 does not require an extra axle to balance it, so I only require the V6. BMW it hasn’t wandered and has been sticking to regular 6-cylinders for decades.

mercedes engine

The turbocharged M 256 is a technological gem, as it introduces an electric compressor, a soft-hybrid version for everyone and a concept without a single belt - all units and auxiliary devices, including the air conditioning compressor, are powered by an electric motor. It is complemented by a full hybrid.

The OM 656 turbodiesel: the convincingness and most important 'pearls' have already been shown and impressed with them in the new E-Class, in the 4-cylinder version of the OM 654. Anyone who claims that diesels go down in history should ask themselves why Daimler introduced the best diesel right now.

The long-lasting version of the gasoline allows for better elasticity and a change of working medium. The OM 653 1.5 will be cut in half, three cylinders and will replace Renault's 1.5 dCi in the new B-Class A edition. All have a turbocharger and direct injection, and this is progress: the new 3.0 biturbo is more powerful than the 12 V600 1990 SEL with 402 hp.

Steel pistons bring success in synergy with the new block: they are almost half as low as aluminum and one of their main assets. In addition, they conduct less heat than aluminum, resulting in higher combustion temperatures, which increases engine performance and further reduces fuel consumption. And because of their smaller dimensions, they are no heavier than aluminum ones. They allow the piston rods to be extended, thereby reducing their swing angle and the lateral pressure of the piston links on the cylinder walls.

The stepped recess at the front of the piston, ie the combustion chamber, is an additional innovation in the production of the piston. Unlike the usual omega-recesses. Such a shape increases the space of the chamber that participates in the combustion process, ie it removes the 'dead space' that cannot be reached by fuel particles. It results in more efficient combustion and better performance, with a reduction in the amount of particles in the exhaust and consumption. Wise innovation!

There is a special NANOSLIDE layer on the walls of the cylinder, which further reduces friction resistance. By electromagnetic process (Twin-Wire-Arc Spraying) at 5000 ° C the material is atomized and a stream of air 'syringe'.

Although it is primarily intended for the S-Class, it will be built into the more powerful E-Class models, with only an automatic transmission.

IMPORTANT

1. PERFECT BALANCE
The regular 6-cylinder has completely balanced inertial forces and moments

2. SIMPLE
It has only one DOHC mechanism and two camshafts, and one block

3. EASY AND RELIABLE
Fewer moving parts and potential breakdown locations are reusable

4. EASY MAINTENANCE
A longitudinally mounted regular version leaves more room for mechanics

5. LOOKING FOR MORE SPACE
It is installed longitudinally, so not all the space from the flanks can be used

Author: Zeljko Marusic

Retrieved from:  www.autoportal.hr


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