Supercharger vs Turbo | FerrariChat

Supercharger vs Turbo

Discussion in 'F1' started by BillyD, Apr 9, 2014.

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  1. BillyD

    BillyD Formula 3
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    Wouldn't a supercharger instead of the turbo have given them a forced induction lump but with better sound?
    I know there must be a reason.
     
  2. tervuren

    tervuren Formula 3

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    #2 tervuren, Apr 9, 2014
    Last edited: Apr 9, 2014
    First of all - they did super charge the cars. A "turbo" is a turbine, an we've shortened and contracted the words Turbine driven supercharger into simply "turbo" in the automotive world.

    The first turbo's actually used hydraulic transmissions to apply the energy directly to the drive shaft. These early turbo aircraft engines were supercharged by belt driven centrifugal super chargers, requiring high RPM to create adequate boost. Taking a high RPM turbine to a lower RPM drive shaft results in large mechanical losses, and a low RPM drive shaft to drive a high RPM compressor is also creating large mechanical losses. The obvious solution that followed after was to have the high RPM turbine drive the high RPM compressor, and voila, the Turbo-Supercharger was born. The size of the turbine had to be matched to the exhaust flow of the motor to keep the super charger from spinning to a point the resulting boost would blow up the motor. This tech didn't really make it to cars for this reason - cars didn't drive around at or near max RPM, but shifted gears using a wider RPM range.

    The invention of the waste gate - allowing intake pressure to blow off beyond the accepted boost of the engine, made turbo-supercharging practical for cars. The waste gate lets you run a larger turbo/compressor than the engine would normally accept, resulting in maximum boost at a point lower than maximum RPM, now, you can run this setup practically in a car and get a decent power band. You are however -wasting energy in the upper range through waste gate bleed off,

    Advances in bearing and electric motor technology, are allowing the F1 turbo's to create drag in the exhaust using electric motors Plug two brushed DC motors together - and if you spin one, you will get resistance as the resulting flow will spin the other motor. Rather than spinning a motor, the electric motors in the Turbo's are plugged into a battery They can either use the motor to resist exhaust flow - harvesting energy for the battery, or to drive the compressor at times the exhaust does not provide enough flow compared to the desired throttle input. The advantage here - is instead of a wastegate - boost levels can be tapered off by increasing drag on the turbine. The "waste gate" energy is harvested, as is a larger percentage of exhaust energy that is normally lost out the tailpipe.

    Its a huge energy savings, although super complicated. Mid corner - the car's exhaust can be used to store energy into the batteries via the exhaust driven turbine generator, then use some of that energy to generate extra manifold pressure when the turbine wouldn't have the energy to do it from lower exhaust flow of not being full throttle.

    There are three compressor types used for super charging, the centrifugal, used where maximum power/efficiency is required, and two others that are less efficient the greater the velocity, but provide a stronger boost in their earlier stages. Its far more efficient to harvest exhaust energy to drive these compressors, than driving them off a belt. The compressors speed/power will also directly relate to the engine RPM. With a centrifugal, you either end up with an undriveable power curve that is a slug right up until its time to shift gears, or with the other two, you have huge energy loss at maxx power.

    So technical answer - these cars already are supercharged.
     
  3. william

    william Two Time F1 World Champ
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    A supercharged engine can makes the same sound than an atmospheric engine: there is nothing to limit the exhaust gas flow. The supercharger is powered from the crankshaft .

    In a turbocharged engine, the turbine is part of the exhaust system and is powered by the exhaust gas flow. A turbocharger uses what would be wasted energy. Because it restricts the free flow of gas, a turbocharger acts as a sound damper.
     
  4. Duck_Hollywood

    Duck_Hollywood Formula Junior

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    wouldn't a super charger add more weight? and stress to the engine? no matter if it is gear driven or belt driven, probably less reliable because of the added parts, not to mention a failure of the super chargers belt or chain, could cause major damage in the power unit compartment.
     
  5. william

    william Two Time F1 World Champ
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    A supercharger is less efficient than a turbocharger.
     
  6. PDX_214

    PDX_214 Formula Junior

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    A supercharger would give a better unrestricted exhaust note (subjectively) but would rob the engine of "flywheel" horsepower. It's more parasitic drag than a turbocharger but there is no "turbo lag", since it is always producing boost. I'm sure they could come up with a drive system not reliant on the crankshaft though, much like the current turbo driven/ERS/MGU-H system to lessen the HP loss. That could be pretty cool actually. Like william said though, a turbo is more efficient, but a supercharger can produce more consistent power.
     
  7. tundraphile

    tundraphile F1 Veteran

    May 16, 2007
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    I find the current turbo F1 cars to be fascinating pieces of engineering. They are using the turbo boost, controlled completely by the use of the hybrid electrical system, to smooth out the ugly power curve that is inherent in a highly-tuned Tiny V6 engine. It makes the car both easier to drive while also allowing incredible fuel economy considering the power levels. It is as close to the engineering ideal engine for a sports car as has been built yo date, IMO.

    The sound is definitely an issue, although I think we will adjust.

    It will only be a matter of time before one of the manufacturers incorporates something similar into a road car, who knows maybe somewhere in Japan Honda engineers are working on NSX version 3.0 with a 3.0L turbo V6 making 500 hp and getting 35 mpg.
     
  8. nsxrebel

    nsxrebel Formula 3

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    Turbochargers are exhaust driven (yes, F1 turbos are electrically driven as well)

    Superchargers are mechanically driven.

    Some corrections.

    A wastegate is not made to relieve intake pressure, it's meant to relieve exhaust pressure on the turbine side of the turbo.

    A blow off valve (BOV) is made to relieve intake pressure on the compressor/intake side of the turbo.
     
  9. PDX_214

    PDX_214 Formula Junior

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    We're probably still quite a few years off from having a MGU-H set up on road cars, but a small displacement, high boost turbo v6/8 is very feasible. I am not a fan of the current crop of hybrid tech on road cars, especially with the political overtones creating "necessity". It'll probably be 10 years before we have reliable systems similar to F1 of today. Unfortunately I doubt we'll still be "driving" them by then. Too much park assist, brake assist, etc., and that's where most manufacturers are heading. I mean just look at the new commercials for the Mercedes SUVs. It's scary.
     
  10. nsxrebel

    nsxrebel Formula 3

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    Where we're going, we don't need no roads.
     
  11. tervuren

    tervuren Formula 3

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    Correct, missed on your corrections.

    Turbochargers are mechanically driven as well, I guess its a pet peeve from being an aviation nut as whether it gets power from gears/belts off of the crankshaft, or power from an exhaust driven turbine, or from an electrical motor, or an entirely separate engine system, super charging is using a compressor to raise air density beyond levels the intake would naturally create. Turbochargers being super chargers doesn't really create an issue for me unless someone asks supercharger vs turbocharger, in which case, it drives me freakin nuts. OR, in this case, with 2014 F1 power-plants that are using both electrical, and turbine power for the compressor.

    I somewhat understand the slang we have today that leads to my confusion, so I try to be understanding, however, you can have a turbo engine without any boost - the turbine instead applies its power to the output shaft. Turbo props are turbine driven airplane propellers for example. To save confusion, I normally ask what compressor type is in use if someone is talking about supercharging, then ask what they are using to drive it.



    These F1 cars are using a centrifugal compressor to supercharge the engine, the compressor is driven by a combination of turbine and electrical power as needed. The turbine and electrical system are also used to harness electrical/chemical energy from the engine exhaust.

    PDX_214, the reason for your statement, is many gear/belt driven super chargers are using compressor designs that are less efficient at greater pressure differentials, or at higher input shaft speeds/power levels. This results in a flatter boost level despite changes in engine RPM. Car's like the BRM V16(fantastic sounding car) used a centrifugal compressor for maximum power and efficiency at high RPM, made the car a pain to drive as max power and max RPM came at the same time, finally get power, and time to shift. If you had an engine like a 8V Porsche 944 that has breathing problem at higher RPM, you could use a centrifugal supercharger and get away with it.

    Frankly, I find what the F1 power plants are doing a real "Duh, why didn't I think of that".

    I personally, love this season's cars. A huge step backwards in aero design that makes them racier as they return to lower noses. If the nose rules were exaggerated requiring even lower/large front noses, we could see a return to beautiful cars like the F1-89. RBR made a gorgeous car, they are the saving grace of many ugly cars on the grid. Requiring even larger/lower front noses could help with the ugly.

    There are insane political pressures at work in western European countries these days. I do not see these energy recovery/supercharger driving turbines going away. From a sound perspective things will be changed forever I'm afraid, no more Dino V6's, BRM V16's, Ford/Cosworth V8's, BMW V10's, Honda V12's, etc. Audio recording of vintage racers screaming around tracks are going to be a lot more valuable.

    From a sound perspective - there is no way to get around that any new rules package will try to take advantage of harvesting exhaust energy.

    It will be interesting to see if fan pressure can overcome political pressure and get a return to the engines most vocal fans want.
     
  12. Remy Zero

    Remy Zero Two Time F1 World Champ

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    Simple terms, what's the difference between super chargers and turbo charges?
     
  13. william

    william Two Time F1 World Champ
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    Roughly speaking, the way they are driven; mechanically for superchargers, exhaust driven for turbochargers.
     
  14. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
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    There are three ways to compress air in a continuous fashion. The Centrifical pump, the Roots blower, and the Whipple Screw. All can achieve compression of air. Roots is more effective just off idle, Whipple is more efficient in the mid-range, the centrifical compressor is more efficient up top.

    All of these create a charge well above atmospheric pressure, or a supercharge. Ths, all are superchargers.

    There are a variety of means to drive a compressor. There is the axial turbine, an electric motor, the crank shaft.

    A "turbo" is an axial turbine hooked up to a centrifical pump by way of a shaft.

    The thing on a Top Fuel Dragster is a roots blower attached to the crankshaft by way of a belt.

    The C6 ZR1 is a Whipple Screw attached to the crankshaft by way of a belt.
     
  15. Mozella

    Mozella Formula Junior

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    You've presented the most accurate post yet; however, since this is the internet and picking nits is the norm, I'll say this:

    You omitted the axial compressor from your list of general ways to continuously compress air. Not only is it is the most common way to compress air for jet engines, it is the type of compressor used on the Latham automotive supercharger, popular in the mid 50's.

    Some background. Early jet engines used centrifugal compressors since a reasonable compression ratio could be achieved by a single rotating part (often with back-to-back blades on a single disk). These engines are simple to make, don't require highly accurate parts, and they are quite robust. But turning the airflow a couple of times reduces efficiency. But they were popular early on because early jet engines with axial flow compressors suffered from poor compression ratios.

    Now, with improved manufacturing capability it's possible to make multi-stage axial flow compressors for jet engines with high compression ratios and high efficiency. Axialflow Engineering Co. is currently producing auto superchargers using an axial flow design similar to the old Latham supercharger.

    Whipple is a well known brand name selling screw type superchargers, but the product is really a type of Lysholm supercharger named after its inventor, Alf Lysholm who developed his products in the 1940's. And I just learned that Alf got his inspiration from a pretty darned sophisticated German design patented in 1878. The Roots brothers patented their blower in 1869, I'm told the same year John Force was born. ;)
     
  16. william

    william Two Time F1 World Champ
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    There is also the Vane type supercharger that uses a non concentric rotor.

    The Shorrock supercharger was very popular on dragster motorcycles and small capacity engine.
     
  17. LightGuy

    LightGuy Three Time F1 World Champ
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    This.
    Leave superchargers to Nascar.
    Turbochargers are for F1.
     
  18. william

    william Two Time F1 World Champ
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    Incidentally, the Roots blower was never intended to be used as a supercharger, as the patent document reveals

    The Roots brothers designed it as a fan to improve ventilation in their factory. The first Roots blower was made of wood!
     
  19. miketuason

    miketuason F1 World Champ
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    Why not both so you'll have power all the time. Lancia did it on their Delta S4.
     
  20. LightGuy

    LightGuy Three Time F1 World Champ
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    In supercharger technology I look back to what the boys in WW2 were doing when results didnt mean winning a race but losing your civilisation.
    Literally the best and the brightest were assigned to the task.
    Most of the configurations, including this Lancia set up, were tried.
    I love them all but a straight turbo is a marvel of simplicity and efficiency.
     
  21. tervuren

    tervuren Formula 3

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    #21 tervuren, Apr 10, 2014
    Last edited: Apr 10, 2014
    Under the new format - you have a maximum fuel flow rate - and you have a limited amount of fuel loaded in your car. The solution is not about what makes the most power, but what makes the most power out of a given amount of fuel.

    The centrifugal supercharger has the highest efficiency in common use - so that makes sense for the compressor. This supercharger also is designed to work with very high RPM on its input to generate boost. Turbines are a good power source where high RPM is needed, so it makes sense to power your compressor from a Turbine. You have an expanding flow of hot gas coming out the exhaust of the cylinders - it makes sense to use this gas to power your turbine that powers the compressor.

    Downside is when you want to get on it off of a corner, there is not enough exhaust flow to fully power the turbine to spin your compressor to generate higher air density for the engine intake. The car you reference - solved this by having two superchargers of two different compressor types, one with lower efficiency driven off the crankshaft providing boost at times there is not enough exhaust flow, and a higher efficiency supercharger driven off of a turbine as described above. A clutch can be used to cut power to the lower efficiency type only using it when needed.

    It is extra weight, less effecient, and provides an edge of letting the car produce large amounts of power over a wider range of condition. With 8 speed gearboxes, F1 cars are operating in smaller rev bands, so that bonus is out. The only downside remaining to not using a system like the S4 had is a delay from when you open the throttle, as you will have to wait for increased exhaust flow, that then brings the turbine up to power to generate boost.

    The F1 power units already allow electric motors to power the car, so here's the kicker, the turbine is not just being used to power the supercharger, its also used with a electric generator on the same shaft as the turbine and compressor, when the power of the turbine outweighs the needs of the energy for the supercharger, the generator can create drag limiting the speed and boost of the supercharger. In the past, this energy was wasted by either bleeding exhaust in a bypass of the turbine and/or bleeding the pressure on the engine intake side of things, which wastes that potential energy. That same generator - can be used as an electric motor to spin the compressor at speeds higher than the exhaust flow would allow. This means that as soon as the throttle gets opened - the supercharger can be electrically powered until the turbine unit produces the required power to take over. There is no need for two separate low/high RPM compressor designs like the Lancia used, as the high RPM compressor design can be brought to a high RPM whether the exhaust gas is sufficient for it or not.

    Converting kinect(turbine) to electrical energy to chemical(battery), back to electrical, then kinetic gain to drive the car or supercharger will lose power to losses at each step, however, this energy is being recovered where a great deal of it would normally be wasted. Given the restrictions on fuel - the setup they've arrived at makes the most sense as it is getting the most use out of the fuel, and is massively responsive in its fuel use as the intake air density going into the cylinders can be controlled.
     
  22. william

    william Two Time F1 World Champ
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    It's the easiest and cheapest way to get power.
     
  23. tervuren

    tervuren Formula 3

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    It amazes me how the USA military is stuck on Jet Turbine engines in high loiter applications - when a turbo-prop is far more fuel efficient. I guess its mostly aesthetics, but the range/power/speed of the TU-95 is fantastic with its turbo driven props.
     
  24. nsxrebel

    nsxrebel Formula 3

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    What are you talking about? The USMC, USN, USCG and USAF are still using the C-130 platform to this day. I was a crew chief/loadmaster/avionics tech in the USMC and USAF and flew in C-130 E/H/J and KC-130 F/R/T/J models.

    The AC-130 and now the KC-130J with its Harvest HAWK weapon system, are probably the highest loiter applications we have and they are turbo-prop. Some of the UAV's are also turbo-prop.
     
  25. william

    william Two Time F1 World Champ
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    Yes, in some applications, the turbo prop is superior to the jet engine.

    I think the TU-95 holds the World Air Speed Record for propeller aircraft.
     

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