BMW three-cylinder engine set to feature in next-gen MINI

By Matt Brogan | May 07th, 2010

Following reports late last year that BMW are constructing a new ultra-efficient three-cylidner engine, comes news today that the German manufacturer could feature the frugal powerplant in its next-generation MINI models.

As fuel consumption standards become more stringent, BMW CEO Norbert Reithofer confirmed his brand is indeed readying its first ever three-cylinder engine, and although specification or fuel economy figures have yet to be confirmed, BMW has hinted that despite the engine’s reduced capacity, we’re not likely to see any drop off in performance, the new MINI Cooper model to deliver at least 89kW.

That means the MINI Cooper S model should pack around the same 134kW power rating.

It is rumoured the new three-cylinder engine will be of approximately 1.3-litres in capacity and will score direct injection and a small variable geometry turbocharger. In a car such as the MINI Cooper, rough estimates put the engine’s combined cycle fuel economy figure at 4.7L/100km.

Robin Graves

The only thing wrong with a 3cyl is the sound.

Handsome_Al

What’s wrong with the engine noise? Too quiet? Too motorcycle like? No gurgle noise? Whats wrong with it? Perhaps if that the case, every turbo engine should have that annoying blow off valve fitted then..
Devil’s Advocate

I wouldn’t say something like a Triumph Speed Triple with a pipe sounds bad…
Robin Graves

It may be ok for a motorbike that revs quite high, but 6000rpm in a 3 cyl sounds like 4500rpm in a 4cyl. They sound awful.

Bezza

Their current 1.6 Deisel will already do 4.7l/100km with the right box so why the bother over develpoing a new engine?

dasferg

134kw reasons!

lazybones

Wow, give it 5 years and we’ll be reading about the new improved 1 cylinder, direct injection, turbo charged, supercharged BMW Motor…..
Valet Dabess

i wonder how much power ferrari could get out of a naturally aspirated 1.3L 3 cylinder…

DGS

well Triumph seem to do well enough (a bike that can get to 300km/hr)

I am sure Ferrari would be able to make something of it so long as the vehical was light enough, but why stuff around with naturally aspirated??? Go the whole hog and give it direct injection and a variable vane turbo.

Don’t let capacity put you off, the Mazda RX7 was 1.3 litres and they could keep people well enough amused.

daan

A triumph cant do 300klm/h out of the box. Might want to get your facts right before you start ranting.

Shak

Interesting news, but i find it hard to belive that a 1.3 three cyl will get 134Kw.

PN

The soon to be released Audi S1 with a 1.4L twin charge engine will be putting out over 150kw, so a tuned 1.3L ‘could’ achieve these figures!

Shak

Fair enough, but wouldnt you have to rev the nuts off of the 3 cyl to get those result, unles BMW are planning a twincharger or something of that ilk.

Stoney!

I don’t understand why they have done this, a 1.3 is pretty big in 3 cyl terms, why not keep it as a 4 cyl, the inherent roughness of a 3 cylinder being ‘off balance’ will no doubt be a tough chore for BMW to smoothen out, 3 cylinder’s can be quite loud but if done right can also give some quite characterful noises being an odd number of cylinders.

Stoney!

Robin Graves

5cyl has the best ‘inherent’ balance. 3cyl arent too bad either balance wise, similar to an inline 6 without the torsional problems in the crank.

AAA

Even or a Kia Rio or a Yaris can have 4 cyl. Why can’t a “BMW” have 4 cyl?
Karl

It makes sense….
If you’re going to design a 4 cylinder motor of x capacity, keep the same capacity but drop a cylinder makes the motor smaller, lighter and has less reciprocating mass.
Its more efficient.

MGH

Also the motor might have the benefit of having fewer moving parts to go wrong.
AAA

Fewer cylinders to average out the reciprocating mass = more vibration ~

svd

Fewer cylinders means larger pots to make the same capacity and if given the same gearing equals less firings per kilometre equals lower fuel consumption. Tolerances do not have to be as fine as they have to be for multicylinder engines to maintain fuel efficiency ie a 10 th of a millimetre on a 100mm part is less of a difference than a 10th of a millimetre on a 75mm part and so on.
RD

It’s interesting that when a German company does a 3cyl engine it makes news and everyone is praising it. Have we all forgotten that the Japs have been doing good 3cyl for decades??

Handsome_Al

Yeah the japanese must be laughin at us…
Hung Low

The japs had the Suzuki Cappuccino (660cc dohc turbo), Daihatsu Charade etc (1000cc DOHC turbo)!

I agree 1300cc is too large for a 3 cylinder, but the aim of the game is economy.
A combustion stroke in a 3cyl will occur every 240deg of the crank vs 180deg of a 4 cyl…….saying that I do not expect a triple of this size to be very inherently smooth unless it gains further refinement from tight tolerances and balanced components!

svd

The Germans have also done a good 3 cyl engine in the past and the DKW 3 cyl 2 stroke springs to mind wich was adopted by SAAB in the 50′ 60′s. There were a number of 3 cyl diesel engines used in commercial vehicles as well. A three cyl has an inherint balance that the 6 cyl in line engine also has with only a crankshaft harmonic imbalance which can be cured with a harmonic balancer. There may be load vibrations at specific engine rpm if laboured at lower rpm. The engines can sound good as well, better than 4 cylinder engines as well as the fact that the timing of the exauhst pulses help scavange the other cylinder at the start of its exhaust stroke. A reason why many twin turbocharged 6 cylinder engine designers utilise this feature by treating the engine as 2 three cylinder engines joined together.