"Car Tech 101: Understanding engine configurations"
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Cooley On Cars
Cooley On Cars
Car Tech 101: Understanding engine configurations
Now I would need a mini series to cover all the pros and cons of the different engine configurations.
What each is good at.
Or bad act.
And even then, no two engines geeks honor really agree with each other let alone me.
So we're not gonna go super deep into that.
Instead I'm going to lay out and visualize for you how each major engine layout is done.
And give you some conventional wisdom on what it's benefits are.
Inline engine is perhaps the simplest, most basic, and most common.
This an inline-4, one of the Ford ecoboost motors.
And this gets its name because the cylinders are arranged in a line, if you look down from the top.
Inline-4s are very common.
Inline-6s are very common.
These engines are known for being very compact, light-weight, simple, inexpensive to build relatively, and because these engines are so compact it's almost square if you view them from the top.
You can mount them either way.
Longitudinally, running the length of the car, or transversely, running across the car, and many different cars use.
One or the other.
Now the V engine, you know mostly as V6's and V8's these days.
Although you can go all the way down to V-twins, in motorcycles, V4's, Saab, Lancia, Ford have all made those back in the day.
But the conventional V8 looks like this.
Here's your Ford Shelby V* for example and theres your v.
Right there in the front.
You've got one set of four pistons and cylinders that are laying over this way.
Another set laying over this way.
So kind of like you took two inline fours.
Married them to one crankshaft and just tilted them apart so they could live in one space.
The key here is that you're fitting a lot of cylinders into a relatively compact space.
Especially when you get to higher cylinder counts like six or eight or ten.
This V8 if you made it into an in line eight would be like this long, it wouldn't fit in just about any car out there.
But by nesting it in a v configuration you gain some width.
But you lose a lot of length.
The other key nuance around V engines, this varies by maker, is the angle of this V. Are those cylinders almost touching or are they laid out much further apart?
The angle of that V is one of the secrets sauce items for engine designers.
V8s and V6s are also known as being.
Inherently pretty well balanced.
And, of course, because they pack a lot of cylinders into a smaller space they do get a lot of power.
They're known as high performance engines in most cases.
The W is in many ways a derivation of the V. The most common example these days is the VW Group design that includes a W8 and some Audi R8s.
A W12 and in some Bentleys, and a W16 in the Bugatti Veyron.
Now visualize this W as a pair of V engines that are mated together to drive a single crank shaft, and in this VW design each of those V sets of cylinders are nested.
So they overlap a bit.
If you run an imaginary line sort of.
Down the set of them.
This W has the V engine's benefits of putting a lot of cylinders in a short space, but also its own benefits of putting a lot of cylinders in a narrower, nested space.
Now, the rotary engine.
In the car world, this really means the Wankel rotary engine that has been used in Mazdas for several decades.
Inside an egg shaped combustion chamber, there's a triangle shaped rotor that turns or rotates with the combustion in the spaces that it creates as it spins.
And geared down the middle of that rotor is the shaft that turns and feeds the transmission.
Now, because Wankel rotaries don't have a bunch of pistons and other parts that are jerking up and down, violently changing direction every split second, they can spin at higher RPMs and do so smoothly without self-destructing.
On the downside, they have long struggled with high-ish fuel consumption and emission.
And a struggle for a lot of power.
Largely due to the trickiness of sealing those three tips of the rotor as it sweeps around the engine and it's terrain of spark plug ports, and intake and exhaust openings.
Now let's talk about a flat engine.
[INAUDIBLE] Also known as a boxer, or a horizontally opposed engine.
This is one of the most famous right here in a Ferrari Testarossa.
It's a flat 12.
You've got six cylinders on each side, as you can try to see there.
And on the other side are six more and they are exactly flatly opposed to each other, 180 degrees apart.
The point here is you've got a very low engine, because nothing sticks up.
It can be a low motor that sits low in the car, giving you a lower center of gravity.
Great for performance and cornering.
It's also an engine that is good if you're trying to package the body low for a low, sleek design.
Take a look at, let's say, a Subaru BRZ.
They were able to get a low center of gravity and a low nose because they've got a flat engine in.
These are called boxers because they have pairs of cylinders pistons in them that are punching together at one time in any given direction.
Flat engines are also known for being very balanced because their pistons and connecting rods are literally in exact opposition.
Things tend to just work themselves out and not have a lot of weird vibrations or moments that have to be counteracted with other apparatus like counterweights.
These are engines that are known very well from Subarus.
They have fours and sixes that are their famous boxers.
And of course, the Porsche 9 11 is a flat six.
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