Breaking News: Mercedes-Benz and Bmw working on three-cylinder petrol engines

[AVANTI R5]

Mercedes-Benz and BMW seem to be on agreement in at least one thing. They’re both working on three-cylinder petrol engines that will be launched within the next five years. The three-cylinder turbocharged unit will be installed in all Mercedes-Benz cars up to and including the C-class.

BMW, on the other hand, is designing cars that will suit the noise, vibration, and harshness associated with these three-pot engines. Dr. Thomas Weber, Daimler’s board member in charge of R&D, said that a three-cylinder engine in the C-class is “quite conceivable.” Daimler strategist Johannes Reisenrath said that to improve economy, it’s logical that from four cylinders, BMW can still go lower.

He cited that with a 1.2-liter three-cylinder, the car can have 168hp with a turbo, plus 150-185lb ft, which is sufficient for a mid-sized car like the C-class. Its 6% fuel consumption benefit together with the 95g/km of CO2 fleet fuel consumption as a target means that it’s definitely an option it will consider. Mercedes is working to figure out a way to serve their customers economical vehicles. In a survey it conducted, consumers want three-cylinder cars to be as fast as their current cars. Reisenrath said that the three-cylinder vehicles have a “nice torque punch.”

With the advancement in turbocharging and gearboxes, the cars will be improved further. According to Autocar’s sources from BMW, the next 1-Series has been engineered to cope with the noise and vibration of a three-cylinder engine. BMW has had the same experience in its motorcycles, where its priority is reducing NVH.
[via autocar]

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[E. Nick]

Apocalypse

[Kubek]

"16bhp with a turbo"? WOW!

[cococly]

Originally Posted by E. Nick

Apocalypse

AS long as Ferrari or Porsche doesn't make 3-Cylinder sports cars. I won't go to kill myself just yet

[HybridBoxer]

Well that will most likely be only in Europe, based off your guys' american responses I can almost garuntee you won't see it stateside.

And I think it's supposed to say 168 Hp.

[rallymaniac]

Perfect engine for a MINI

[woody06967]

C120? Gross.

[Chromer]

Originally Posted by rallymaniac

Perfect engine for an Isetta

Fixed. And once the world economy starts picking up, might not be surprised to see that kind of engine here. $4 gas is going to become a fond memory quickly...

[impreza_punk]

Wow imaging slapping two of those bad azz engines together, you'd have a ...oh wait

[whoosh]

why don't we just "cut to the chase" and make a 1 cylinder direct injection, turbo, 4 active valved hybrid?

[Hazdaz]

So what's wrong with 168hp and 150-185lb ft??

Doesn't the Impreza RS (or whatever Subaru calls it now) have about that much power?
Same with the base Camry, Fusion and Accord.

For the most part, most people don't care how a car makes it's power if it has enough "pep" when they drive it. As long as M-B and BMW can find a way around a 3-cylinder engine's notorious shaking, most people are going to be perfectly fine with this.

I would be curious to hear about any potential weight savings that a 3-cylinder might offer, because shedding pounds would be key in using smaller engines.

[sub9lulu]

Originally Posted by Hazdaz

I would be curious to hear about any potential weight savings that a 3-cylinder might offer, because shedding pounds would be key in using smaller engines.

doubt they will be saving anything over the straight 4 with the added weight of the turbo and its component

[HybridBoxer]

Yea but when you think of everything else in the engine that is not required for a 3 cylinder vs. a 4 cylinder it might be quite a few pounds. But also based on the vehicles this engine will be in, it will most likely not make much of a difference. I'd much rather have a turbo 3 than an N/A 4 with a matching torque to HP.

Smaller block, less coolant, less oil, 1 less manifold port, 1 less intake manifold port, smaller head....it all might be enough to offset the baby snail that will be going in there.

[Hazdaz]

^ Ya know, that's an interesting issue. Like at what point does the weight savings make it not worth it? There is the law of diminishing return - you can only reduce the displacement and the cylinder count so far before it makes it unusable/not worth it.

And at what point do these car makers have to look at more "radical" engine designs?

There have been numerous engine designs posted here (and in the OT) that supposedly offer vastly superior mileage and/or power and/or some other benefit, yet many of them seem to be too radical to be taken seriously for car-use. At what point do the car makers start to take a more serious look at ICE designs that are "outside the box"? Or are they simply gonna ride the current ICE design till the electric motor completely takes over?

[Chromer]

Originally Posted by Hazdaz

^ Ya know, that's an interesting issue. Like at what point does the weight savings make it not worth it? There is the law of diminishing return - you can only reduce the displacement and the cylinder count so far before it makes it unusable/not worth it.

And at what point do these car makers have to look at more "radical" engine designs?

There have been numerous engine designs posted here (and in the OT) that supposedly offer vastly superior mileage and/or power and/or some other benefit, yet many of them seem to be too radical to be taken seriously for car-use. At what point do the car makers start to take a more serious look at ICE designs that are "outside the box"? Or are they simply gonna ride the current ICE design till the electric motor completely takes over?

Diminishing returns is a fallacy based on optimizing only one component, with a systemic design approach you get multiplying benefits instead.

But we do look stuck with the ICE until electrics take over. The automakers have big investments (or sunk costs depending on your POV) in facilities for casting and machining engines and transmissions. Inertia...

[Yotsuya]

Originally Posted by Hazdaz

So what's wrong with 168hp and 150-185lb ft??

Doesn't the Impreza RS (or whatever Subaru calls it now) have about that much power?

The WRX skewed everyone's perception of power around NASIOC (i-club) back in 2001. Now everything has to have 300AWHP.

To make that work it's got to have insanely tight tolerances, even with a turbo. Which is why I'm currently looking for a pre-Ford Volvo with a non-interference engine.

[Mike Wevrick]

Originally Posted by Hazdaz

So what's wrong with 168hp and 150-185lb ft??

Nothing, really, in an economy car. It a little wimpy for a sporty or luxury car.

I'm not sure why they would want to go to 3 cylinders though, instead of just a small 4 with a small turbo (eg like VW/Audi's 2.0t)

[Hazdaz]

Originally Posted by Chromer

Diminishing returns is a fallacy based on optimizing only one component, with a systemic design approach you get multiplying benefits instead.

I don't necessarily agree with that. If an engine has 2 cylinders or 4, it still has to be "beefy" enough to take all the internal pressures and such, right? You still need a block thick enough and pistons strong enough and all that other stuff. Sure you can use a smaller quantity of them, but the engine's still gotta work.

But yeah, I get what you are saying - that optimizing one component by 2% and 2% from a bunch of other parts will sometimes net you more than the total of the parts. But my points was that a 4 cylinder is not 1/2 the weight of an 8.

But we do look stuck with the ICE until electrics take over. The automakers have big investments (or sunk costs depending on your POV) in facilities for casting and machining engines and transmissions. Inertia...

It's not even so much that we are stuck with the ICE, but rather stuck with the ICE as we know it today... I mean look at pretty much every car engine out there (except the rotary) and they are have the same general design. There have been some exotic ICE designs that didn't even use pistons or camshafts or valves - they were a completely different design... yet still ICEs.

But alas, your point about inertia is probably why we continue to simply "tweak" the same design over and over again. There are billions of dollars worth of tooling and engineering that have been put into this design - even if it's not the bestest design out there (and no design will ever be "perfect"), any potential pay-off for coming up with something totally different would not be financially feasible.

[Yotsuya]

I thought with the type of hybrids that are being made today an opposed piston engine would be perfect; one crank to power the car while the other charges the batteries.

Of course the Volt's got all that beat.

[Hazdaz]

Originally Posted by Mike Wevrick

Nothing, really, in an economy car. It a little wimpy for a sporty or luxury car.

But go back just 10 years.



The 1999 S-class.
The big boy.
No one would say that it wasn't luxurious. It weighed over 4500 lbs and it's base engine in the US was kicking out only 228 HP. That's not a whole hell of a lot more than this rumored 3-banger and chances are it would be in a car a lot lighter than 4500 lbs.

[bal00]

Originally Posted by Hazdaz

^ Ya know, that's an interesting issue. Like at what point does the weight savings make it not worth it? There is the law of diminishing return - you can only reduce the displacement and the cylinder count so far before it makes it unusable/not worth it.

And at what point do these car makers have to look at more "radical" engine designs?

They're probably doing this to reduce internal friction rather than weight. One less piston moving up and down, one less crank bearing, four less valve springs pushing against the cam etc.
You're also reducing the cylinder surface area which is beneficial in terms of thermal efficiency.

As for all those novelty engines, most of them are designed to maximize access to venture capital rather than efficiency. Ye olde piston engine is pretty damn good at turning pressure into kinetic energy. The tricky part is turning the chemical energy stored in the fuel into pressure without generating too much waste heat in the process, and that's difficult as long as you're burning the stuff.

[WRXVT]

I doubt these 3 cyls will make it to the states... maybe but I doubt it.

In terms of required power... Europe is a whole different story. Heck the 3 series came as a 316i with ~100hp over there until the mid 2000s. I remember seeing BMW 518i's too....

[Jarvis]

Originally Posted by WRXVT

I doubt these 3 cyls will make it to the states... maybe but I doubt it.

In terms of required power... Europe is a whole different story. Heck the 3 series came as a 316i with ~100hp over there until the mid 2000s. I remember seeing BMW 518i's too....

I just got back from Scotland and Ireland and there are all kinds of 2008/9BMW 520d's running around (including a cab we were in). Not sure what that engine puts out, probably a bit more than this 1.2 liter petrol engine, but they seemed plenty fast (and quiet!).

edit: found this review...hp is about the same, but, as expected, the torque in the diesel is pretty high...

"It’s just about quick enough, too. A mere 175bhp and 258lb ft might not sound like much, but it’s enough providing you think ahead and are prepared to use the gearbox."

[JuggernautTCW]

Originally Posted by HybridBoxer

I'd much rather have a turbo 3 than an N/A 4 with a matching torque to HP.

Smaller block, less coolant, less oil, 1 less manifold port, 1 less intake manifold port, smaller head....it all might be enough to offset the baby snail that will be going in there.

umm... did you forget how many extra parts you need to make FI work and how much easier things can break?...

[HybridBoxer]

I should be saying Uhmmm to you. Extra parts to make FI work? Please explain these extra parts. Seriously...BMW and MB have used multiple engines with FI via superchargers and turbos. So it's not like they don't understand the technology. I don't know, I'm getting worked up over nothing I guess.

I think some of you guys are getting the wrong impression of what these engines will be going in. It will be only in europe and most likely A, B, and very low level C-class (plus the other BMW models) cars that we currently don't even have here. People in Europe and other countries are loving all these small engines being used in cars that don't even see alot of abuse. And things breaking? I would imagine things might break less seeing it's such a small engine ,not putting out a lot of power.