ugzannin@sunybcs.UUCP (Adrian Zannin) (01/22/86)
I think i might have an idea, but I am not sure. Could someone please
post a condensed explaination of the difference between turbochargers and
superchargers? What are the advantages of one over the other? Thanks in
advance...
Adrian Zannin
SUNY at Buffalo Computer Science
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--
Adrian Zannin
SUNY at Buffalo Computer Science
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BITNET: ugzannin@sunybcs.BITNETlarry@kitty.UUCP (Larry Lippman) (01/23/86)
> I think i might have an idea, but I am not sure. Could someone please > post a condensed explaination of the difference between turbochargers and > superchargers? What are the advantages of one over the other? The amount of fuel-air mixture which is introduced into an internal combustion engine PER CYCLE is generally referring to as a ``charge''. A ``supercharger'' by definition is any device which increases the amount of charge per cycle above that of a normally aspirated engine. While a supercharger can be anyone of several types of air compression devices, the term ``supercharger'' seems only to be applied to application of such devices to internal combustion engines; i.e., the same air compression device used for another application may simply be called a turbocompressor, rotary vane compressor, rotary blade compressor, etc. From what I can gather, a ``turbocharger'' is a turbocompressor applied as a supercharger. A compressor used as a supercharger can be powered by three means: (1) direct coupled to the engine, (2) powered by a close-coupled exhaust-driven turbine, and (3) powered by an electric motor with speed control. Compressors used in (1) and (3) are low speed (i.e., << 5000 RPM), whereas devices used in (2) are high speed (i.e., >> 5000 RPM). Since turbine technology results in the smallest possible size for a compressor, it is the most common device used in passenger vehicles. Since turbines require higher RPM's than can be conveniently achieved by direct coupling to the engine, and since a turbine MOTOR as powered by engine exhaust gases can generate the required RPM's, the combination of an exhaust- driven turbine motor close-coupled to a turbocompressor is most commonly used in passenger vehicles. I believe most people refer to this device when using the term ``turbocharger''. However, while ``supercharger'' is a precise engineering term, this may not be the case for ``turbocharger'' - even though the two terms are often used synonymously. ==> Larry Lippman @ Recognition Research Corp., Clarence, New York <== ==> UUCP {decvax|dual|rocksanne|rocksvax|watmath}!sunybcs!kitty!larry <== ==> VOICE 716/741-9185 {rice|shell}!baylor!/ <== ==> FAX 716/741-9635 {G1, G2, G3 modes} duke!ethos!/ <== ==> seismo!/ <== ==> "Have you hugged your cat today?" ihnp4!/ <==
andrew@grkermi.UUCP (Andrew W. Rogers) (01/25/86)
In article <2763@sunybcs.UUCP> ugzannin@sunybcs.UUCP (Adrian Zannin) writes: > I think i might have an idea, but I am not sure. Could someone please >post a condensed explaination of the difference between turbochargers and >superchargers? What are the advantages of one over the other? Thanks in >advance... The way I always heard it, the term "supercharger" applied to a mechanically- driven device and "turbocharger" to one driven by exhaust pressure. I have heard rumors that the forthcoming RX-7 "Turbo" will, in fact, use a supercharger. AWR
moroney@jon.DEC (Mike Moroney) (01/26/86)
Turbochargers and superchargers do the same thing, they compress air to force more air/fuel mixture into the cylinders to get more power. The basic difference in automotive language is where the devices get their power. Turbochargers get their power from a turbine in the exhaust system, powered by exhaust pressure. Superchargers (often called "blowers" by racing types) are belt-driven, like the alternator, water pump, etc. Advantages to Turbochargers: 1) Use "free" power (exhaust power) 2) Physically smaller, since the device uses higher RPM's (as much as 100K) Disadvantages: 1) Turbo "lag" between the time you step on it and the turbo kicks in 2) Non-linear function of throttle position and power (many people with turbo's love this, though) 3) Potentially unreliable, because of the high temperature from exhaust + high RPM's (they are pretty good now, however) 4) Not too useful at low RPM's Supercharger advantages: 1) Linear power response, like a bigger motor 2) No turbo "lag" Disadvantages: 1) Uses motor power 2) Can be large (racers often have them sticking through the hood) -Mike Moroney ..decvax!decwrl!rhea!jon!moroney
svirsky@ttidcb.UUCP (William Svirsky) (01/27/86)
In article <715@decwrl.DEC.COM> moroney@jon.DEC (Mike Moroney) writes: > >Advantages to Turbochargers: > >1) Use "free" power (exhaust power) >2) Physically smaller, since the device uses higher RPM's (as much as 100K) One more advantage is that because the turbo doesn't "kick in" at lower RPM's, you can drive the car for economy, by shifting early, or drive it for speed, by shifting late. -- Bill Svirsky Citicorp/TTI 3100 Ocean Park Blvd. Santa Monica, CA 90405 Work phone: 213-450-9111 x2597 {philabs,randvax,trwrb,vortex}!ttidca!ttidcb!svirsky
larry@kitty.UUCP (Larry Lippman) (02/02/86)
> Turbochargers and superchargers do the same thing, they compress air to force > more air/fuel mixture into the cylinders to get more power. The basic > difference in automotive language is where the devices get their power. > Turbochargers get their power from a turbine in the exhaust system, powered by > exhaust pressure. Superchargers (often called "blowers" by racing types) are > belt-driven, like the alternator, water pump, etc. > > Advantages to Turbochargers: > > 1) Use "free" power (exhaust power) > ... Nothing is "free" in this world... The turbine motor which powers an exhaust-driven turbocharger gets its power from the exhaust gases by paying the price of increasing exhaust backpressure, thereby increasing engine load and decreasing engine efficiency. There is not a great deal of power (when compared to total engine output) expended to run the turbine motor, but it could be as much as several BMEHP at high rpm's. The resulting power gain from the turbocharger action more than justifies the power required to drive the turbine motor. The same thing is also true of a direct-coupled Roots-type supercharger; the engine power required to operate this blower is more than justified by the increased power gain. ==> Larry Lippman @ Recognition Research Corp., Clarence, New York <== ==> UUCP {decvax|dual|rocksanne|rocksvax|watmath}!sunybcs!kitty!larry <== ==> VOICE 716/741-9185 {rice|shell}!baylor!/ <== ==> FAX 716/741-9635 {G1, G2, G3 modes} duke!ethos!/ <== ==> seismo!/ <== ==> "Have you hugged your cat today?" ihnp4!/ <==
junk@ur-tut.UUCP (Jan Vandenbrande) (02/03/86)
Refering to the loss of power due to the increase in exhaust pressure by adding a turbo charger on your car. I believe that you have to look where you try to get the energy from. As much as I remember my thermodynamics class (oh what a nightmare) it isn't so much the pressure of the exhaust gasses as it is the combination of pressure and the TEMPERATURE difference between what you have after it leaves the engine and what you have outside. Hot exhaust gasses still have alot of energy in them, which usually goes to waste. Turbo chargers try to use some of this energy to press more air/fuel stuff in you combustion chambers. Correct me if I am wrong. Jan .