Diesel design history

[CrabbyMilton]

I would really only apply this to 4 cycle diesels but I was wondering, with all of the engines these days moving toward turbocharging, has there ever been an OEM that offered supercharging? It seems to me that there was but I couldn't find it so perhaps it didn't last long in production. Turbocharging has most of the advantages but what about supercharging? Must be something to be said about "super diesels"?
I understand gasoline engines are different but FORD can't seem to build enough turbos for the F150 since it's almost split down the center vs. non turbo.

[luvrbus]

The older Cummins offered super chargers in different models but I haven't seen any of the newer models with superchargers.Cummins offered the NH with supercharger or turbo.
They had the J series then too lol we would joke about the J series the JT we called it just trash the JS model we called it just sh**. Supercharged engines use power the turbo use waste that why everything is turbo now     

[Scott & Heather]

Superchargers do create some parasitic loss. They are belt driven or gear driven so that's a thought to keep in mind. Turbos have much less parasitic loss, though there is some since it's creating resistance during the exhaust stroke of the piston. Some diesels are supercharged and in the case of our two strokes they are both


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[luvrbus]

Cat is bring back the supercharged engines in the marine engines I read a article last year they are getting 650 hp from the 8.7 with  a supercharger

[Geoff]

Thank you, Professor, but the blower on a 2-stroke Detroit acts as an air supply, whereas a supercharger acts as an increased air pump.  The blower on a 2-stroke Detroit is not a supercharger.

--Geoff

Superchargers do create some parasitic loss. They are belt driven or gear driven so that's a thought to keep in mind. Turbos have much less parasitic loss, though there is some since it's creating resistance during the exhaust stroke of the piston. Some diesels are supercharged and in the case of our two strokes they are both


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[Scott & Heather]

Lol. Geoff I'm not a professor, just throwing out thoughts. Here's some info I gleaned off the web. Kinda points to the fact that blowers and superchargers aren't all that different in their purpose of feeding air.

Superchargers and blowers also differ in size. Blowers stick out of the hood, while superchargers fit in. A supercharger is an air compressor that increases the pressure or density of air inside the combustion engine. It pushes air into the engine, increasing its density and allowing the engine to have more oxygen-intake cycles. Superchargers can be mechanically driven by use of a belt, shaft, gear or a chain connected to the engine's crankshaft. Conversely, blowers use centrifugal force to propel air forward. There is no major difference in how blowers and superchargers work, because they both use forced induction.
Superchargers can be compared to pumps because of the displacement that occurs with a stroke of pump. On the contrary, blowers act as fans, because they apply less displacement while functioning. A supercharger and a blower could appear as having no difference, given that both are air compressors. However, the functioning of the two is different.


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[buswarrior]

The terms "blower" and "supercharger" are generic, and in popular language, are used interchangeably.

Lets name the various ones we know of?

"Roots style" is what we 2 stroke Detroit owners have, and certain ones were swapped and bolted onto gasoline engines by the early hot rodders.
Anytime you found a 6-71 in a scrap yard, the blower was ALWAYS gone...

What else is out there?

happy coaching!
buswarrior

[luvrbus]

The terms "blower" and "supercharger" are generic, and in popular language, are used interchangeably.

Lets name the various ones we know of?

"Roots style" is what we 2 stroke Detroit owners have, and certain ones were swapped and bolted onto gasoline engines by the early hot rodders.
Anytime you found a 6-71 in a scrap yard, the blower was ALWAYS gone...

What else is out there?

happy coaching!

Blowers come in 3 different configurations the roots are used on most Detroit's the centrifugal type which some 6L 110 Detroit's used so did some EMD made by GM then you have the screw type used on Cat and Cummins.
I have a screw type Stewart and Stevenson a Detroit dealer developed for use on the high hp 92 series to churn out 625 hp from the 6v92's.That is the only 3 types I know of.I am not real sure but I believe the auto manufactures used the screw type on their supercharged engines high performance engines,  the roots type are the most common found          
buswarrior

[Jeremy]

I think I'm right in saying that some modern city buses nowadays use switchable electric superchargers on the diesel engine part of their hybrid power systems. Because the diesel engine component of the system is quite small, and because the buses are constantly having to accelerate from stationary, they use the electric supercharger to boost the engine power in a clean-emissions kind-of way at times when the engine is at low revs and running inefficiently

Jeremy

[Geoff]

I think I'm right in saying that some modern city buses nowadays use switchable electric superchargers on the diesel engine part of their hybrid power systems. Because the diesel engine component of the system is quite small, and because the buses are constantly having to accelerate from stationary, they use the electric supercharger to boost the engine power in a clean-emissions kind-of way at times when the engine is at low revs and running inefficiently

Jeremy

I was reading a automotive magazine about 48 volt engine systems in hybrid engines and part of the function of the electrical system was to start spinning the turbo before the car moved to eliminate turbo lag.  Once moving the exhaust would turn the turbo cutting off the electric booster.

--Geoff

P.S. I worked on an old Cummins (2-6 bits?) that used a supercharger and it had written on it ROOTS so a roots blower was an actual brand.

[Jeremy]

Roots was the name of the inventors according to Wikipedia (and presumably nothing to do with Rootes, which was once a major car manufacturer in the UK)

https://en.wikipedia.org/wiki/Roots-type_supercharger

Jeremy

[DoubleEagle]

Thank you, Professor, but the blower on a 2-stroke Detroit acts as an air supply, whereas a supercharger acts as an increased air pump.  The blower on a 2-stroke Detroit is not a supercharger.

--Geoff

When all the drag race enthusiasts took the "blowers" off the 6-71's and put them on gas V-8's, they were called "superchargers". The real difference between all the types of chargers is the pressure boost and the thermodynamic efficiency of the drive method. To call the "blower" on a 2 cycle an "air supply" might be off the mark. There was a teeny bit of positive pressure involved so that all oil leaks could be revealed.

[TomC]

The main reason that a mechanical supercharger is not used on a 4 stroke Diesel is the supercharger is pumping 100% air all the time creating a constant 30-50hp draw on the engine. Compared to a gasoline engine with a supercharger-since the supercharger is down from the butterfly valve, when the engine is at idle or no power, the supercharger is not pumping-hence no power robbing. Superchargers are quite efficient on gasoline engines.
Virtually all on road Diesels are turbocharged and air to air intercooled. Most all marine Diesels are also turbocharged and aftercooled too. I can't think of a naturally aspirated Diesel made today (except small Diesels for generators). Good Luck, TomC

[Jeremy]

Just a question for my own interest: Why is it that a 2-stroke Detroit needs a blower if the net result is that the air going into the engine has either no positive pressure, or only a very small positive pressure? Is it that the inlet tract is somehow very restricted and if the engine was naturally aspirated it would struggle to suck sufficient air into the cylinders?

Jeremy

[Oonrahnjay]

Just a question for my own interest: Why is it that a 2-stroke Detroit needs a blower if the net result is that the air going into the engine has either no positive pressure, or only a very small positive pressure? Is it that the inlet tract is somehow very restricted and if the engine was naturally aspirated it would struggle to suck sufficient air into the cylinders?

Jeremy

    No, the DD two-stroke system is different from the configuration used on, say a two-stroke motorbike or a chain saw.  In the other systems, the crankcase is used as a pump, air is drawn into crankcase and fuel metered along with the air (and usually oil is metered, too), then when the piston is traveling downward, the air/fuel mixture is pushed from the crankcase into the volume above the piston.  This is the positive pump action for these systems and ports - at different levels on the cylinder to control timing - allow for transfer and exhaust. 
    On the DD two-stroke, there is little timing effected by the intake ports - when the piston is low, they're open.  The exhaust is controlled by valves in the head (like ordinary 4-stroke poppet valves).  To fill the cylinder with air (fuel comes later), there has to be positive pressure blowing fresh air in near the lower part of the cylinder.  The timing comes from the exhaust valves.  Once enough air has been injected to scavenge the cylinder of exhaust gases, the rising of the piston closes the intake ports and begins the compression phase of the cycle.
    So it's this "flow-through" aspect of the DD two-stroke system that requires positive pressure to help blow out burnt gases through the exhaust and fill the cylinder with fresh air; it's the "blower" that does this.

(Somewhat simplified for brevity, but that's about right.)

HTH and FWIW,  BH etc.