Stupid engine question

I always thought that a V was an acute angle. So if the engine is flat, then it is no longer a V.

That is like saying a straight line is a 180 degree V. Am I missing something here?

 

No, it's like saying an inline configuration is a 360 deg V

 

A boxer crankshaft has two throws between each main bearing and each throw is 180 degrees apart and each throw is used by one con rod.

A V crankshaft has one throw between each main bearing and each throw is shared by two con rods.

 

THAT is what I was trying to say.....LOL!

 

That's exactly correct, and my point....

The V is squashed "flat" if it's 180 degrees, it's still an angle, it's just hiding...

 

Or a 0 degree V

 

+1

 

And just to be sure, wikipedia has an entry for boxer engines:

http://en.wikipedia.org/wiki/Flat_engine

With an animated image showing the pistons moving inward and outward together.

And an entry for Berlinetta Boxer:

http://en.wikipedia.org/wiki/Ferrari_Berlinetta_Boxer

Where the entry states that the engine is not of boxer design.

 

I think that only proves that the C&D writer misunderstood, or mangled, the translation -- no practical IC engine with 6 cylinders in a (coplanar) bank can use a flat crank (it doesn't give an equally-spaced firing pattern). If it does (and you can provide more proof than a 3rd person description) I'll put $50 in your Paypal account...

 

Don't confuse a flat crank with a flat V either...LOL!

Enzo started it, calling the 512 a "Boxer" that confused everybody....LOL!

 

Again my understanding is that when you reference the first description in an engine design, you are referencing the cylinder layout. The second number refers to the engine.

So a Flat 12 cannot be a V12... Flat does not take in account crankshaft throws and angles, but IMO there is no such thing as a 180 degree V12. I understand the concept (in regards to cylinder timing) but the configuration of the engine is flat.

If we start accounting for engine timing then the 430 should not be a V8 but rather a twin I4.

 

Hi Steve,

Perhaps Aston Martin has it wrong too. Or, maybe it's the same linguistically challenged reporter, translating from English to, well, English:

"Expect as much as 700 horsepower from the flat-crank, 7.3-liter V-12."

http://www.motortrend.com/features/consumer/112_0903_2010_future_cars/aston_martin_one_77.html

I'll pm you my paypal account details - thanks.

 

And I'll respond when you provide something more than a 3rd party (magazine) description -- e.g., manf article or photo -- no mention here: http://www.one-77.com/specification.html

Alternatively, if you want to describe how the firing order of a V12 (or, for simplicity, an inline 6) using a flat crank would work, I'm listening...

 

Actually your point is well made a Ferrari V8 IS engineered as a twin I4,.....the 308 is engineered as two 4s joined at the crank, dual distributors, coils everything....

 

Is the 5 valve 355 not really a 5 valve V8 but rather a 4 valve V10 Twin I4? Obviously I'm kidding, and my expertise is far from this area, but this is the first time I have ever heard of of a 180 degree V12 (again, I am not qualified to argue with the experts but only clarify what might be my lack of understanding on the subject of engine configuration).

What I have gathered is that for many people the 'Boxer' term is a combination of engine timing AND cylinder layout. I always took the Ferrari approach and referred to flat engine configurations as Boxer motors. I'm not sure if there is a right or wrong answer, I think you will find that the definition of the term is going to be based on the interperation of the the user.

So a Flat 12 can be a boxer motor (at least in theory) but just because it is a Flat engine doesn't make it a boxer (to most here).

People using the terminology 180 degree V12 are referring to the firing order, in the fact that a 12 cylinder would be unbalanced with a flat 'Boxer' crank. I guess arguing over who is right is going to be the same as debating how to say potato? I pronounced it potato by the way.

I'll stick with flat 12, some will stick with a 180 degree V12, and some will say boxer. Depending on who is listening and who is talking we are all right.

 

+1 - ditto that. Unfortunately, some believe that their opinion is the only right answer, and insist on telling everyone else that they're wrong. And, frankly, if one's personal first hand experience doesn't include professional employment as an engine designer (myself excluded here, like most) then it's pretty difficult to be a credible and definitive authority on the matter.

What I have noted in this thread is merely a couple reviews by credible automobile journals indicating utilization of a flat plane crankshaft configuration in a V-12 production car by both Ferrari and Aston Martin.

 

Steve, that's a good question, for sure. However, I don't have the answer unfortunately.

I'm guessing that if you parked two more pistons/cylinders on either end of this flat crank V8 ( http://www.youtube.com/watch?v=I29P3K6POu4 ) - for a total of 12 - with those extra two on each end lined up in the next logical rod journal location (of a flat plane crank) then you'd have the basic crank/rods/pistons configuration. As to the firing order, well, I'll have to think on that for a bit!

 

Couldn't you just time one cylinder on each pair of the extra four cyclinders 1 rev out of phase with it's sister? Then you'd have symetrical power pulsing?

 

No, you get sort of a bilateral symmetry, not true symmetry. Although Brian already explained this, let me try this way:

For an inline 4 with a flat crank:

one cylinder fires
180 deg of rotation
one cylinder fires
180 deg of rotation
one cylinder fires
180 deg of rotation
one cylinder fires
180 deg of rotation...

For an inline 6 with a flat crank, the best you can do is:

one cylinder fires
180 deg of rotation
two cylinders fire together
180 deg of rotation
one cylinder fires
180 deg of rotation
two cylinders fire together
180 deg of rotation...

(and would have horrible first-order torque pulsation)

 

Steve,

If the car magazine reports on ferrari and aston martin are correct, then I would guess that some technical details will emerge that might clarify what/how their engineers are dealing with harmonics/vibration issues. There certainly is a means to make a flat crank operate in almost any engine configuration from single cylinder (by definition, single plane!) to 12 cylinder. Whether those configurations operate in acceptable ranges of performance and longevity/comfort is, of course, the heart of the issue and it's at least conceivable that the skunk works in either ferrari or aston may have come up with something new. So, I suppose, stay tuned.