Central Pollution Control Board (CPCB) has already started stressing on the implementation of BS V emission norms in the engines which are in their initial stage of Research & Development. So, Automotive manufacturers are garnering possible techniques to amend the existing emission norms.
One of the techniques used by the manufacturers is Engine Downsizing(ED). Engine Downsizing simply refers to increasing the power of the engine, without necessarily increasing its weight. This can be easily attained by the incorporation of Turbo-chargers and Superchargers.
Nearly every diesel car in the market is Turbo-charged nowadays. Turbo-petrols will also be commonplace soon. When in comparison with superchargers, turbo-chargers are efficient at lower rpm range.
Engines used in day-to-day cars are usually under-squared and have an rpm limit of 5000-7000 rpm. But turbos can spin upto 150,000 rpm! So, they can easily reach the temperature range of 150 degree Celsius without inter-cooling. The inertia will keep the turbos rotating at high speeds even when the engine is turned off.
So, for better heat dissipation, oil-cooled turbos are even employed. Apart from that, it also suffers from a main drawback, TURBOLAG. It is a phase in which turbos don’t acquire enough thrust from the exhaust to power up the engine. Generally, TURBOLAG exists even up to 60-70 km/hr. In order to reduce this range, Variable Geometry Turbos (VGT) are employed.
So, even with some drawbacks, Turbos are efficient and will definitely be influencing the upcoming downsized engines for sure.