Why dont we get Supercharged Diesel car engines?
Discussion
I have seen supercharged marine deisels, and even better, supercharged two stroke deisels. We have them on some oil rigs for generators. V12's and their pistons are about 8 inches in diameter!
A very old supercharged two stroke deisel was the rather odd Commer TS3, which was the only true boxer engine I have ever come across, (3 cylinders, 6 pistons!)in that the pistons came together in a common cylinder, and was fitted in some trucks. The con rods were attached to a large rocker to another con rod, and then onto a common crank. Very odd set up, but very powerful.
A very old supercharged two stroke deisel was the rather odd Commer TS3, which was the only true boxer engine I have ever come across, (3 cylinders, 6 pistons!)in that the pistons came together in a common cylinder, and was fitted in some trucks. The con rods were attached to a large rocker to another con rod, and then onto a common crank. Very odd set up, but very powerful.
vlc said:
as we only hear about turbo-diesel powered cars, does that mean 'supercharged-diesel' cars aren't worth building, or possible?
an if so then why?
for you get them for petrol engines as with turbo's...
Turbochargers are powered by energy that would otherwise be wasted so they are providing power for free.
Given that diesels are there to save fuel it makes sense to not waste it by powering a supercharger and let the energy of exhaust gas go down the pipe without driving anything.
It is certainly a feasible project to build a supercharged diesel, response off the line would be stunning.
Slightly off thread, and wayyyyyy too big for cars, but what about Napier's Deltic for a supercharged two stroke diesel ?? Three cranks, 18 cylinders, opposed pistons....... www.lexcie.zetnet.co.uk/delticengine.htm
Phil.
Phil.
Bollocks, I missed that. I love supercharged two-stroke diesels. I have a long-term project to build one in V-twin format for a bike engine.
Two-stroke diesels need plenty of air for scavenging, so they have to be blown. And it has to be with a crank-driven supercharger; a turbo won't give you any scavenge air at start-up. You can have a turbo take over once it's got the revs up though. Indeed, you can extract more energy from the exhaust than is needed to drive the compressor, and add it to the power available from the crank - this is what the Napier Nomad aero diesel did.
Two-stroke diesels need plenty of air for scavenging, so they have to be blown. And it has to be with a crank-driven supercharger; a turbo won't give you any scavenge air at start-up. You can have a turbo take over once it's got the revs up though. Indeed, you can extract more energy from the exhaust than is needed to drive the compressor, and add it to the power available from the crank - this is what the Napier Nomad aero diesel did.
Pigeon said:
you can extract more energy from the exhaust than is needed to drive the compressor, and add it to the power available from the crank - this is what the Napier Nomad aero diesel did.
also known as turbocompounding - think the big two stroke train/ship diesels use this.
N
mad jock said:
I have seen supercharged marine deisels, and even better, supercharged two stroke deisels. We have them on some oil rigs for generators. V12's and their pistons are about 8 inches in diameter!
A very old supercharged two stroke deisel was the rather odd Commer TS3, which was the only true boxer engine I have ever come across, (3 cylinders, 6 pistons!)in that the pistons came together in a common cylinder, and was fitted in some trucks. The con rods were attached to a large rocker to another con rod, and then onto a common crank. Very odd set up, but very powerful.
There should surely be a not between very and powerful in the last line. They were difficult to keep cool too. If you wish to read about one find a test of the Ecurie Eccosse transporter.
Ok guys - so are we saying a supercharged diesel is better than a turbo-diesel if you had to race with either of them?
an why would some trucks have them instead of a TD.
an why dont bmw an Landrover use them in their premier 4WD cars, or dont they have any real performance advantage over a TD engine?
any body?????
an why would some trucks have them instead of a TD.
an why dont bmw an Landrover use them in their premier 4WD cars, or dont they have any real performance advantage over a TD engine?
any body?????
A turbo charger, more properly called a turbosupercharger is merely one of many types of supercharger. You need to be more specific if you require a definitive answer and you also need to think about drive systems, it all gets a bit complex (not comprix or centric they are yet more types of supercharger).
The real attraction of a turbo blown production engine is the lower cost of developing an instalation and the way the market is seduced by a swelling of power as the revs rise.
The real attraction of a turbo blown production engine is the lower cost of developing an instalation and the way the market is seduced by a swelling of power as the revs rise.
gnomesmith said:
A turbo charger, more properly called a turbosupercharger is merely one of many types of supercharger.
I think vlc is making the distinction between exhaust-driven (turbo) and crank-driven (super).
Is it because diesels tend to produce their peak power at lower revs and therefore don't need the extra boost at low crank speeds? Only guessing...
I think Jaguar are planning a supercharged diesel in their new sportscar, apparently a bit like the XK180 that never made it.
As I understand it a turbocharger is driven by exhaust gases, whilst a supercharger is driven mechanically from the crankshaft. That's why turbos only work above a certain rpm, whilst the effect of a supercharger is proportional from standstill.
They certainly worked on Bentleys and Spitfires
As I understand it a turbocharger is driven by exhaust gases, whilst a supercharger is driven mechanically from the crankshaft. That's why turbos only work above a certain rpm, whilst the effect of a supercharger is proportional from standstill.
They certainly worked on Bentleys and Spitfires
gnomesmith said:
comprix or centric they are yet more types of supercharger.
What ???????
what is he saying - i thought for years there were 2 forms of engine-asperation...turbo-charged or super-charged.
former is powered from exhaust gases / latter is powered direct by the engine.
so what these other types i never heard about....?
[anorak=on]
Depends on the shape of the rotor I think - some have vanes to force the fuel/air mixture through under pressure, Others have a screw arrangement. VW used a "G" shape (hence the Golf G40). Different types are commonly named after the manufacturer that developed them (e.g. Roots)
A Comprex is a "pressure wave" supercharger developed by Brown Boveri.
[anorak=off]
Depends on the shape of the rotor I think - some have vanes to force the fuel/air mixture through under pressure, Others have a screw arrangement. VW used a "G" shape (hence the Golf G40). Different types are commonly named after the manufacturer that developed them (e.g. Roots)
A Comprex is a "pressure wave" supercharger developed by Brown Boveri.
[anorak=off]
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