Effect of mounting the engine in transverse direction

[ninjaz]

When i observed the mounting of engine in different vehicles , one thing i found is almost every heavy trucks and pickup vans have engines mounted in longitudinal direction and in small cars in transverse direction.
Is this just related with packaging factors are something more?

 

[dgallup]

Primarily by which axle is driving. Front engine / rear drive is always longitudinal because there has to be a long longitudinal drive shaft. Front engine / front drive is mostly transverse because it avoids an inefficient right angle turn of the power train and packages in less space. There have been numerous longitudinal front engine / front drive vehicles but they are the exception.

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[BrianPetersen]

A review of the history of drivetrain layouts will find just about every practical layout has been tried.

Front engine rear axle drive, always engine longitudinal with a 90-degree turn at the axle, I know of no exceptions.

Rear engine rear drive can be:
- longitudinal with the engine behind the axle (traditional VW air-cooled Beetle, Porsche 911, original Fiat 500, Fiat 126, many others)
- transverse with the engine behind the axle (many Subaru and Suzuki minicars of the past, NSU Prinz, probably others)
- longitudinal with the engine ahead of the axle "mid engine" (Porsche Cayman)
- transverse with the engine ahead of the axle "mid engine" (smart fortwo, Mitsubishi i, Toyota MR2, Pontiac Fiero, Fiat X1/9). It is tricky to have a back seat with this layout. The Mitsu does it, and for that matter the smart fortwo as well even though it is too small for a back seat, by having the wheels all the way to the back and the engine tilted backward at a steep angle. The crankshaft is ahead of the rear wheel centerline but the cylinder head is behind it.

Front engine front drive can be:
- transverse with engine ahead of the axle (almost everything nowadays)
- longitudinal with engine ahead of the axle (most Audis, Chrysler LX cars Concorde Intrepid etc., most Subarus)
- longitudinal with engine BEHIND the axle (original Renault 4 and 5 "LeCar", some early Saabs, Cord 810 from the 1930's)

All wheel drive can be any of the above and there are examples that can be found of all of them. Remember that most all-wheel-drive vehicles have a design basis that starts out as one of the above. A Subaru Impreza is fundamentally, at its heart, a front-drive car, and so is an Audi A4. A 4x4 pickup is fundamentally a front-engine rear-drive.

 

[GregLocock]

You forgot transverse engine in front with RWD. Not wildly popular but it has been done.

Cheers

Greg Locock


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[Lou Scannon]

You forgot transverse engine in front with RWD. Not wildly popular but it has been done.

I think Brian intended to ruleit out:

Front engine rear axle drive, always engine longitudinal with a 90-degree turn at the axle, I know of no exceptions.

I can't think of any modern cars with this configuration (i.e transverse front engine, RWD) but it is extremely common with cycles, both motorized and human powered. I guess many early horseless carriages sported this configuration, with chain drive.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[GregLocock]

http://www.drivingenthusiast.net/sec-ford/FMC-engines/t-drive/default.htm

Cheers

Greg Locock


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[BrianPetersen]

True that transverse engine rear drive is popular on motorcycles ... I have four motorcycles that are all like that!

But in a car, it doesn't make a whole lot of sense. Two 90-degree turns are needed (assuming that you are going to take the drive to the rear with a shaft rather than a chain the way my bikes do) and gearing to turn a 90-degree corner is less efficient than parallel shafts.

Transverse engine in the manner used in most front-drive cars (and in the rear, in smart fortwo and Mitsubishi i) eliminates all 90-degree turns in the gearing and it eliminates having a separate housing for the transmission and final drive, and it eliminates a couple of shaft seals (assuming that the drive shaft from transmission to final drive is open, as it normally would be).

Transverse engine requires that the engine be at the same end of the car as the primary driving wheels, be that the front or the rear.

And on that note ... I present a couple more layouts that I hadn't thought of before, in transit buses!

Transverse engine, angled-longitudinal transmission, rear axle drive! This layout was used for decades on GM transit buses. The "New Look" or "fishbowl" buses built from the 1960s through the 1980s were all like that. The transmission was called "angle drive" and was a real oddball. I'm pretty sure that Allison was the only manufacturer of transmissions like that, and they are no longer built.

And ... Longitudinal engine in the rear with rear axle drive, but with the engine not centered in the vehicle (it's generally on the extreme left). Lots and lots of buses are like this. It allows a few more seats for passengers on the right side of the bus, alongside where the engine is. The rear axle is basically normal, but the differential is well off to the side rather than its usual place in the middle.

 

[BigClive]

Longitudinal rear (mid) engine and FWD layouts also exist - in forklift trucks etc.

 

[GregLocock]

I didn't say it was a great idea, merely that it wasn't entirely unheard of.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Lou Scannon]

I didn't say it was a great idea, merely that it wasn't entirely unheard of.

ditto

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz