[saxonb]

Mercedes-Benz has developed a new six-cylinder in-line petrol engine that has for the first time been systematically designed for electrification. New, intelligent turbocharging, e.g. with an electric auxiliary compressor (eZV), as well as an Integrated Starter-Alternator (ISG) provide the guarantee of excellent drivability with no turbo lag. ISG is responsible for hybrid functions, such as boost or energy recovery, while allowing fuel savings that were previously reserved for high-voltage hybrid technology. The bottom line is that the new six-cylinder in-line engine offers the same performance as an eight-cylinder machine while being much more fuel-efficient. The new petrol engine (internal code: M 256) launches next year in the new S-Class.

The six-cylinder in-line engine features systematic electrification. For example, there is no belt drive for ancillary components at the front of the engine, which reduces its overall length. The narrow construction, together with the physical separation of intake/exhaust, creates space for near-engine exhaust aftertreatment. At 500 cc, the new engine has the same displacement per cylinder as the premium diesel engine family unveiled last year as well as the family of four-cylinder petrol engines. An additional bonus is the unsurpassed refinement of the six-cylinder in-line engine.

The output and torque of the new six-cylinder in-line engine are similar to the current eight-cylinder machine, i.e. over 300 kW (408 hp) and more than 500 Nm. In comparison with the previous V6, the CO2 emissions from the engine have been reduced by around 15 percent.

Its performance is as dynamic as that of a V8, as the new six-cylinder in-line engine comes with an especially intelligent form of turbocharging: assisted by the ISG at start-off, the electric auxiliary compressor (eZV) guarantees immediate high torque when driving off and accelerating, bridging the time before the large exhaust turbocharger cuts in. The electric turbocharger accelerates to 70,000 rpm within 300 milliseconds, ensuring an extremely spontaneous reaction from the engine. The result is a dynamic engine response with no turbo lag.

The M 256 is the first member of a new family of premium petrol engines that have for the first time been systematically designed for electrification from the outset. The 48 V electrical system serves not only high power consumers, such as the water pump and air-conditioning compressor, but also the Integrated Starter-Alternator (ISG), which also supplies energy to the battery by means of highly efficient energy recovery. The ISG dispenses with the need for a belt drive for these components. This not only reduces the overall length of the engine and its complexity, but also paves the way for new, efficient control possibilities. The still existing 12 V system supplies power to consumers such as lights, cockpit, infotainment and control units.

The ISG is a key component of the 48 V system and not only serves as an alternator, but is also responsible for hybrid functions. This allows fuel savings that were previously reserved for high-voltage hybrid technology. For the first time, the ISG is also responsible for idle speed control. The hybrid functions include:

Boost: 15 kW/220 N
Energy recovery
Shifting of the load point: the engine can be operated in a more favourable area of the engine map; load increase/reduction depending on the state of charge of the battery
Coasting
3S start: almost imperceptible reinstatement of the engine
Another feature of the new family of premium petrol engines is near-engine exhaust aftertreatment. The as-standard particulate filter is the only part of the exhaust system that is under the floor. The M 256 is produced at the Untertürkheim plant.

[Wolf 335]

No serpentine belt...Sold.

[pgviper]

Very cool! Its funny, FI was used to increase fuel economy meanwhile real world results for many resulted in the same or worst.

This seems to be the alternative that will actually start to push the mpg threshold that many manufacturers find themselves stuck at.

Imagine a real world engine with some guts that can get > 25 city mpg and > 35 hw mpg??? That would be fantastic.

[Chihuahua]

Very impressive.

[MightyMouseTech]

Originally Posted by pgviper

Very cool! Its funny, FI was used to increase fuel economy meanwhile real world results for many resulted in the same or worst.

This seems to be the alternative that will actually start to push the mpg threshold that many manufacturers find themselves stuck at.

Imagine a real world engine with some guts that can get > 25 city mpg and > 35 hw mpg??? That would be fantastic.

It's called the Freevalve engine. Google it.

[mkoesel]

You beat me to it - wanted to open discussion on this.

To answer the question you posed in your thread title, I don't think the M256 in initial spec is meant to compete with the S55. It's really a replacement for Mercedes existing V6 engines, which it will do over the next three years or so.

Later, I would definitely expect an AMG version. And furthermore, I expect them to be able to do upwards of 170hp/L since their M133 I4 hits ~190hp/L and their M177/M178 V8 goes up to ~150hp/L. This means over 500hp. Of course that is using today's engines as a barometer. By the time an AMG version hits, five years may have passed and 200hp/L may be possible. We'll see.

I will add that I think this still-theoretical-but-nearly-certain-to-come AMG version will replace the M177 V8 in the next generation of the C63 and GLC63 (the first generation GLC63 isn't even out yet, but it will be very shortly). I could even see it slide in on the low end of the AMG GT lineup. I think a ~500-ish horsepower AMG GT with this I6 at, say, $95k would be a big seller. They would have to discontinue the lower end V8 model and bump the other two up, of course.

Bottom line is that between this engine and VAG's new twin turbo 2.9L V6 coming soon to the RS4/RS5, the competition over the next few years looks fierce. BMW will be forced to step it up which is a good thing. It will be interesting to see whether they build on the back of the water-injected S55 with a future S58 or if they have something different in mind (electric assist, like Mercedes is using).

[FriskyDingo]

Impressive. I like what I'm reading. I foresee the S Class getting rave reviews with this.

[Sedoy]

Pretty cool stuff, check how closely catalytic converter located to the engine, I wonder how it's getting cooled:



This is new 48-Volt ISG (Integrated Starter Generator) adds extra 20hp:



And new BorgWarner eZV (еlectric auxiliary compressor) which helps main turbo from 1000—3000 rpm, so this makes this engine turbo/e-supercharged like some Volvo's:

[Dackelone]

Alpina is getting 408 PS and 600Nm out of their 3.0liter bi-turbo bmw based engine. I think the real figures are about a 100PS and 100Nm more - judging by a recent test drive I took.


PS: I think its great MB is getting back into the straight six arena.

[ShocknAwe]

Very cool, but Merc = No Manual