Increasing engine displacement is a solution for increasing power in cars. But the government has some regulations and also increasing engine displacement will also increase fuel consumption. So, manufacturers are continuously trying to increase power of engines without increasing the displacement to save fuel. Two technologies for this purpose are turbocharger and supercharger. In this blog we will know about Turbocharger vs Supercharger and know which is better.
Turbocharger vs Supercharger
Today we will be comparing turbochargers vs superchargers more at a high level standpoint and talk about the pros and cons about each. Both of these have the same goal of increasing power while keeping fuel efficiency high. But they go about doing that in very different ways. So, what can make us choose one over the other? Let’s find out:
Which is better?
- A turbocharger uses the exhaust air to spool up a turbine. This turbine then powers an air compressor which pulls in more air and feeds it to the engine. From an efficiency standpoint, a turbocharger leads the war because what you are using here to power it is something which is just a waste- the exhaust air!
Whereas, a supercharger is powered by the engine itself.
- Manufacturers use turbochargers to downsize their engines as smaller engines can also make more peak power now. This doesn’t necessarily mean you will get more mileage but this removes some weight from the car and can boost overall fuel efficiency. Then why should we pick a supercharger instead of this? We will find that out soon.
The primary reason is, the turbochargers have a lag. We get the power but it is not instant as it works with the exhaust air.
A supercharger is powered by the engine itself. This is an advantage of the supercharger over the turbochargers as this leads to instant power delivery. With increasing rpm of the engine, the supercharger functionality also kicks in, so you feel the power just by stepping on to the pedal.
- Another reason for choosing a supercharger over the turbocharger tis that it gives the boost over a wider range of speeds. In turbocharger it is selective, you may have a boost in low end performance or a decent mid range boost.
- In turbocharger there is a throttle control issue. As there is a lag, so you may press the accelerator pedal and think okay that is all I’ve got. But later, the turbo adds more power. So, you can’t really access the situation when it will come to your benefit.
- Additionally, the turbochargers need lubrication and is done with the engine oil. This is an extra demand on the engine oil. They need lubrication in the turbine shaft as well as the bearings within the turbo
These are some of the reasons why we generally see superchargers in cars rather than the turbochargers.
How do turbochargers work?
Before discussing the working principle of turbochargers, let us discuss the components of a turbocharger. A turbocharger has three components- a turbine, a compressor and some bearings to support the turbine shaft.
Alfred Buchi, a Swiss engineer is credited with the invention of the turbocharger. In a four stroke diesel engine, air is forced into the engine by atmospheric pressure. This is known as a naturally aspirated engine. During high rpm as in highway driving, atmospheric air won’t force much air into the engine. Here, a turbocharger comes into play.
A turbocharger has a shaft with a turbine wheel on one end and a compressor wheel on the other end. These two ends look almost similar.
The axle’s gas enters this system from the inlet pipe to the turbine wheel section. Also, exhaust gas is collected. Here, in the turbine section, kinetic energy is produced. As the compressor wheel is located in the same structure, it rotates at the same speed as the turbine wheel. The compressor in turn, draws air and compresses it and then it passdes through the outlet pipe and supplies the engine with oxygen.
For the turbocharger to work efficiently, another component is added in between the path from outlet pipe of the turbo to the engine. This is called an intercooler. The air from the compressor is hot and needs to cool down for more oxygen supply to the engine.
There are different types of turbocharger according to their mechanism of working.
- Single-Turbo. This is the simple type of turbo we've discussed.
- Twin-Turbo. As the name suggests, twin turbo means another turbo is added to the engine. There are two turbos in this case which increases the power further
- Twin-Scroll Turbo. In this case, the inlet pipe is divided into two and different cylinders deliver differently so that more exhaust gas can be fed.
- Variable Geometry Turbocharger (VGT). This reduces the turbo lag significantly. The gas is made to flow at different angles. So, at low rpm too it works.
- Variable Twin-Scroll Turbocharger (VTS). This adds the advantages of both the twin-scroll turbo and the VGT.
- Electric Turbochargers. This setup is the solution for many turbocharger cons. At low speed, the turbo doesn't get enough power. At the time, an electric motor powers the compressor in this setup. This setup ensures there is no turbo lag.
That’s enough of turbochargers, now let us look into the superchargers.
How do supercharger works
Supercharger setup contains a housing with a compressor impeller. As soon as the impeller rotates it acts like a reverse fan which draws air. This impeller almost achieves 1,00,000 revolutions per minute. Air gets drawn in quickly. Superchargers have tooth belts or V belts and a planetary gear system which can handle 1,00,000 rotations per minute. With a chain which is connected to the engine’s crankshaft a supercharger works.
The major advantage of a supercharger is it’s very efficient in its job. There is no lag and instant power from this system.
To sum it up, turbocharger and supercharger both have their own method of working. If someone wants better performance from the car then a supercharger is good but if someone wants more fuel saving along with performance then turbochargers are recommended.