Advantages of a turbocharger over superchargers
A turbocharger enjoys a small efficiency advantage over a supercharger in most situations, but not always.
Most people mistakenly think a turbocharger "converts heat into work". A turbocharger generates all of its power through the difference in pressure from the engine side to the exhaust side. Part of its power comes from restricting the engine, creating higher pressure in the exhaust manifold. This is an inefficient process as the turbine can only capture 50% of the energy it cost the engine doing this.
The other part of its power comes from the fact that when each exhaust valve opens at the bottom of the power stroke, the cylinder pressure is quite a bit higher than atmospheric (aka, there is extra potential energy that was not captured by the piston). This waste energy is turned into a sonic wave as it suddenly is released into the exhaust port. The turbine absorbs some of the momentum of the wave when it hits the blades and transfers it to the compressor. This process is also inefficient, but the waste energy was free since it was going to be absorbed by the muffler and environment in the first place, which is why turbochargers are more efficient overall when designed well.
With technologies such as BMW's experimental electrically assisted turbos (that have already been used in F1), lag will be reduced a bit and the turbine can be designed to cause less backpressure and have higher efficiency now that it is not the sole source of compressor power.
Most people mistakenly think a turbocharger "converts heat into work". A turbocharger generates all of its power through the difference in pressure from the engine side to the exhaust side. Part of its power comes from restricting the engine, creating higher pressure in the exhaust manifold. This is an inefficient process as the turbine can only capture 50% of the energy it cost the engine doing this.
The other part of its power comes from the fact that when each exhaust valve opens at the bottom of the power stroke, the cylinder pressure is quite a bit higher than atmospheric (aka, there is extra potential energy that was not captured by the piston). This waste energy is turned into a sonic wave as it suddenly is released into the exhaust port. The turbine absorbs some of the momentum of the wave when it hits the blades and transfers it to the compressor. This process is also inefficient, but the waste energy was free since it was going to be absorbed by the muffler and environment in the first place, which is why turbochargers are more efficient overall when designed well.
With technologies such as BMW's experimental electrically assisted turbos (that have already been used in F1), lag will be reduced a bit and the turbine can be designed to cause less backpressure and have higher efficiency now that it is not the sole source of compressor power.
- Turbocharger can spin much faster than a super charger , as the speed of supercharger is limited to the speed by the speed of crankshaft. A turbo in a F1 car can revolve at 10,000 to 40,000 RPM.
- Supercharger are parasitic , they eat a part of power produced by the engine.
- Most turbocharger are electronically driven , to eliminate Turbo lags ( only during lesser RPMS) .
- A turbocharger sits between a exhaust system of a automobile , so there is restriction for the exhaust gas to flow , this causes back pressure that tries to block the exhaust. So the engine must do more work to expell out all the burnt gases.
- Super chargers come in three forms centrifugal , screw and Vane type . The vane and screw type superchargers can deliver air at little higher pressures than a turbocharger.
- No turbo lag , so good response for the throttle.
- Turbochargers require cooling systems as its in contact with exhaust gases. This is not problem in supercharger. The charge of air delivered is at a lower temperature than a turbo.
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