Flat 12 engine

An animation of a flat 12 engine. 6 piston pairs firing at every 60 degrees. Notice that the layout is NOT a boxer, 2 pistons share a common crank pin.

Category:

Autos & Vehicles

Tags:

• Engine
• animation
• flat-12

[dynosor1]

You have the middle 4 pistons moving together. This would result in vibration that can be avoided by using a boxer configuration - find an accurate Porsche engine animation to see what I mean.

[TheRenalicious]

@dynosor1 Thanks for your reply and concern about the validity of the information. I got my info from Wikipedia that states "Flat-12 engines are generally not true horizontally opposed engines (boxer), but rather 180° V-engines". Naturally I assumed it was two straight-6 engines put together at 180* since the straight 6 and V-12s are such balanced engines. I'll research more and ensure my animation is accurate :)

[dynosor1]

@TheRenalicious If you made the V angle of your modeled engine 60 degrees, the crank would represent the typical arrangement used by almost all V12 engines, including Ferrari and the Rolls Royce Merlin.

While a 180 degree V engine is theoretically possible, a 12 cylinder boxer could be made with a lighter crankshaft because the opposing loads cancel each other. Can you name any vehicle that uses or used a 180 degree V12 engine?

[TheRenalicious]

@dynosor1 The Porsche 917 did according to this website "pbase com/917carl/917_12_cyl_engine"

[TheRenalicious]

@dynosor1 Here is a Porsche flat-12 engine sectioned off. The crank layout is that of two straight 6 engines linked together. "tinyurl com/5wmux7s"

[SparkDischarge]

@SparkDischarge A boxing engine [boxer] tries to balance itself locally. One piston/connecting rod is directly opposed by another-well as close as it can be.

A 180 degree V12 [straight angle] does not do that. The balance model is that of 2 inline6 engines running on a common journals, which is the same as any V12.

One could make a 180 degree V2, 4, 6, 8, 10, they would be odd firing. So it behooves one to make the more complicated, but even firing, boxing 2, 4, 6, 8, 10.

[cruzmaq]

@SparkDischarge what designates something to be a "engine style" then anyway? Your reasoning behind this argument seems so abstract. I think that a flat (boxer) engine IS a different engine style because it doesn't use a V-style engine crankshaft while still using a flat-V styled block.. not totally same as a flat-V block though

[SparkDischarge]

@cruzmaq 'flat' is an adjective, not an engine style.

Inline is the easiest design. Adding two inline engines together in a Vee formation is the next easiest design. Expanding that Vee design to 180 degrees (straight angle) is slightly more difficult.

Now you take that straight angle Vee engine, modify the crankshaft so you split the journal 180 degrees. That is a boxer engine.

There is no need for a boxer 12 engine, because a 180 degree V12 is still balanced (2 inline 6 engines)

[cruzmaq]

@SparkDischarge I dont really understand the point you're making, but a boxer engine is absolutely not a V-style engine. It's closer to an inline engine than it is a V-style engine

[SparkDischarge]

There is no such thing as 'FLAT' engine. You could lay an inline engine 90 degrees to the vertical, would that be 'flat'?

This is a 180 degree V12, straight angle if you will.

Boxing engines are 180 degree Vee engines, with a 180 degree splay angle on the crankshaft throws. (regardless if there is an extra bearing for the crankshaft)

Honda's boxing 6 motorcycles have 4 main bearings.

Subaru's boxing 4 car engines have 5 main bearings.

[Skater3z3b]

@dynosor1 I think the Testerossa was a flat 12 not completely positive but that would be the car to look at.

[howyoudone]

great animation videos man. great job.

[JSnyder49428]

How would this differ from a true flat 12? I know its because of the 2 pistons per crank pin but i mean what are the advantages/disadvantages of each?