Diesel design paradigm - V6 & V8
Diesel design paradigm - V6 & V8
(OP)
Just throwing out a question for discussion - Would it make sense to swap the intake and exhaust ports on a V6/V8 diesel engine? My thinking is that you put the turbo just above the flywheel and eliminate the convoluted exhaust plumbing. (see this picture for a relative location http: //www.just -auto.com/ articleima gelist.asp x?ID=90659) And then the intakes could routed to the outsides of the heads with no limitations with high temps. The heat from the exhaust wouldn't cook the things that bolt to the side of the engine or next to the engine in the engine bay.
I assume that this layout has been tried before, but curious if there are problems with this or just that the standard layout is too ingrained?
ISZ
I assume that this layout has been tried before, but curious if there are problems with this or just that the standard layout is too ingrained?
ISZ





RE: Diesel design paradigm - V6 & V8
A turbo in that location, above the flywheel, would interfere with traditional body structure in a car or truck, or force you to move the engine forward, which is not usually a good thing.
Caterpillar adds a second turbo to a 1000HP marine inline six, mounted above the flywheel. It makes the exhaust plumbing considerably more complex, but uses space that is normally wasted on a boat, so the overall engine is relatively compact.
Mike Halloran
Pembroke Pines, FL, USA
RE: Diesel design paradigm - V6 & V8
The OP does not specify an application, but he does mention engine bay which implies it is not a stationary motor.
A cab over truck normally has the bell housing under or behind the drivers seat. This would leave room for the turbo there.
If the engine was over head cam or had an insulated valley cover, I don't see that much more temp going to the oil. With the outboard exhaust, the rocker box is directly opver the exhaust. With the inboard, it would be below and beside. I don't see a lot of difference.
Main problem will be lack of room between cabin floor and exhaust manifold, but if this was not a problem in the specific application, the idea would simplify exhaust routing and turbo location with shorter pipe lengths. If there was plenty of overhead clearance with ventilation at the top, the heat would actually escape easier.
The commercial and economic problems of a complete head, induction and exhaust system change for a small volume application is another matter which will probably make the idea unviable.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Diesel design paradigm - V6 & V8
Packaging - Mike, look were the turbo is on the 7.3L and 6.0L powerstoke, between the last two cylinders.
Neutral
- I think that either way you run into heat issues which can be addressed.
Positive?
- Preservation of pre-turbo exhaust energy with the reduction in plumbing?
- Would it give better catalytic converter light-off at start-up?
- Better pulse scavaging with a common exhaust manifold?
Negative?
- Could you make an exhaust manifold that wouldn't crack due to thermal expansion?
- Would it grow too much between the heads and have leakage problems?
RE: Diesel design paradigm - V6 & V8
Mike Halloran
Pembroke Pines, FL, USA
RE: Diesel design paradigm - V6 & V8
You would need twin turbos or a slip fit between the two manifolds prior to single turbo. The slip fit would at best be difficult to do and unreliable or leaky and probably very expensive. Maybe a stainless steel bellows.
The packaging problems listed by Mike will make it undoable in a normal front engine with cab behind firewall type layout.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Diesel design paradigm - V6 & V8
Even in turbo applications, intake plumbing is quite large so it is questionable that spacesaving or a reduction in convoluted plumbing would materialize from exhaust on top.
(Detroit=blue, CAT=yellow)
RE: Diesel design paradigm - V6 & V8
Mike Halloran
Pembroke Pines, FL, USA
RE: Diesel design paradigm - V6 & V8
RE: Diesel design paradigm - V6 & V8
ISZ
RE: Diesel design paradigm - V6 & V8
Probably the main advantage was that all the really hot items were up high and away from the engine. It was easy to vent as the heat went straight up away from the electronics and other items onthe engines.
99 Dodge CTD dually.