BMW patents turbocharged V6 engine design

Sacrilege. Blasphemy. Treason. Heresy. Just what sin is BMW accused of? Patenting a design for a turbocharged V6 engine. If you're not a BMW fanboy, you may be wondering, what's the big deal?

BMW stands alone as the only major automaker to have stuck with the tried-and-true inline-six engine through thick and thin, and adherents that drink the BMW Kool-Aid have long held that this engine configuration is superior to any other. And they do have a point... BMW's inline sixes are known for their smooth operation (due to their inherently balanced design) and ability to rev to the stratosphere while producing some of the sweetest sounds known to motordom.

Of course, anyone paying attention knows that BMW produces a whole slew of engines, and not nearly all of them put six cylinders neatly in a row – there are V8 engines, V10 engines and inline-fours, too. But the inline six is BMW's bread-and-butter reputation earner. For now.

The boys from BimmerPost have uncovered a German patent application that clearly shows a sequential turbocharged engine design with both six and eight cylinders. It's entirely possible that BMW is merely protecting intellectual property that it has developed for turbocharger routing and design, but the fact that it's shown on both V6 and V8 engines means the automaker is at least thinking about the V6.

Note that this revelation shouldn't come as a surprise to anyone – rumors of a BMW V6 (along with reports of triple turbochargers on various engine layouts) have been around for quite some time. Plus, we're going to trust that the engineers at BMW know a thing or two about engine design, and they'll surely settle on a choice that fulfills the performance parameters they are looking to achieve. Anything is possible...

http://www.autoblog.com/2011/09/09/b...engine-design/

 

strange of them to step away from i6

 

i wonder what are some other pros and cons with i6 vs v6. would v6 be potentially easier to design / work on for efficiency?

 

A V-6 is easier to package because it's short length makes a smaller unit. V engines typically don't have as nice a port design for the heads because they're limited in the way they can design the ports - this is especially true for a V-6 since the cylinders need to be at 60 degrees for primary balance control. V-8s are set to 90 degrees so they've got a bit more flexibility with the ports, but they've got a pretty wide package at 90 degrees between the cylinder banks.

Inline engines have very long and very flexible cranks compared to a V of the same number of cylinders. The same is true for the engine block - it has to be pretty heavy to be strong because it is so much longer than it's V counterpart.

From a manufacturing perspective, inline engines are easier to machine and can be built with cheaper tooling. V engines are more challenging because you have two separate decks and tolerance stacking can make some pretty frustrating problems getting them out the door in a warranty survivable state.

If both engines have overhead cams, the weight on the V will be a bit more because you've got four separate cams and the necessary gear to drive them, also with four cams, getting cam timing right is a tad more challenging, although with modern electronic valve timing adjustment, this isn't the issue it once was.

Speaking of primary balance, and inline 6 is smooth as silk without a whole lot of shenanigans. V-6s are not, and they sometimes employ counterbalance shafts to quell harmonics and make them less buzzy. Counterbalancers rob power, but they do make the package a smoother drive.

I'm not sure why BMW would choose to abandon their inline 6 for V engines, but I'm certain they have their reasons if they do.

 

interesting, great info lance. seems like there are more pros to go with i6 over v6. so in terms of performance / gas mileage, the two don't make much difference? i wonder if space is really that big of a deal for them

 

I was never that into the inline 6.

 

When Mercedes-Benz built their first V6 engines in 2000, they gave them the not-so-ideal 90-degree V-angle (before then, their 6-cylinder engines were Inline-6 engines). By doing that, they could share parts with their 90-degree V8 engines.

Could BMW be doing the same thing? Their 90-degree V10 engine spawned a V8. Could their new V6s be based off their V8 engines?

 

They could. If they go that route, they'll built cranks with offset adjacent rod journals so they effectively have 60 degree spacing. Detroit did this, and so have a few other manufacturers. They could also go the counterbalancer route. I'm not a fan of either of these bandaids, but they work well enough for street duty.

 

why not? the bmw inline 6 is one of, if not the smoothest, most flexible and sweetest sounding engines on the planet.

i'm sure you prefer the clattery sound of that subaru boxer.

 

beat me to it



I wonder what models are going to be using the V6.