Supercharger vs Turbocharger
One of the key factors affecting the efficiency of any internal combustion engine is the air supply. If the air supply is lower than the required, the fuel-air mixture undergoes partial combustion inside the combustion chamber/cylinder and the net power delivered is lower than the rated value. This problem is characterized by black exhaust emissions and lack of power from the engine.
If the air is supplied continuously at the air-fuel ratio required, fuel air mixture undergoes complete combustion and the engine delivers the maximum power. The problem is solved by supplying compressed air into the air intake of the engine by an external mechanism, and the process is known as forced induction. Supercharger and the Turbocharger are two types of devices used to create forced induction in internal combustion engines.
What is a Supercharger?
A supercharger is an air compressor used to increase the mass flow rate of air into the engine so that the fuel-air mixture undergoes complete combustion with the excess oxygen present in the mixture. Based on the mechanism used to compress the air, the superchargers are categorized into positive displacement type and dynamic compressor type.
The positive displacement type uses a positive displacement pump for the compression and supply air at a constant rate to the engine. The main types of positive displacement pumps used are the Roots, Lysholm twin-screw, and Sliding vane pumps. Among dynamic compressors, centrifugal type and the multistage axial compressors are the most common.
In superchargers, the compressor is driven by the power supplied by the engine and, therefore, less efficient. The superchargers may well consume 1/3 of the power produced by the engine at the crankshaft, also creating a high rate of fuel consumption in the engine. Power from the shaft may be delivered to the supercharger by belt drive, gear drive or by chain drive, creating a further classification in the supercharger types.
The advantage of superchargers is the quick response to request to increase of power, since the compressor is directly powered by the engine.
What is a Turbocharger?
A forced induction compressor driven by a turbine powered by the exhaust gas of the engine is known as a turbocharger.
Rather than using engines shaft work to power the compressor, the exhaust gas collected from the cylinders is directed to a turbine connected to the compressor at the air intake. As a result, the efficiency of the engine is high, and the fuel consumption stays low. Thermal efficiency, or fraction of energy in the fuel-air mixture that is converted to output power or shaft work, is always greater with a turbocharger than with a mechanically driven supercharger.
What is the difference between Supercharger and Turbocharger?
• Superchargers are powered by the engine itself and use a fraction of crankshaft power, while turbochargers are powered by a turbine driven by the engine exhaust, therefore, do not use any of the crankshaft power.
• Superchargers are less thermal efficient than the turbochargers.
• Superchargers have a shorter response to the throttle than the turbochargers.