What is the principle behind supercharging?

• A. To increase the density of the fuel-air charge by compressing the mixture before it enters into the cylinders.
• B. To increase the displacement of the engine
• C. To reduce fuel consumption by lean burn
• D. To reduce compression ratio

Answer: (A)

Supercharging works by forcing more air into the engine by compressing the intake air with a mechanically driven compressor. By increasing the density of the air entering the cylinders, more oxygen is available for combustion on each intake stroke. With more oxygen, you can burn more fuel in each cycle, producing greater power without increasing the engine’s displacement. This boost is achieved because the compressor is driven by the engine, so added airflow is available across a wide range of speeds (unlike a turbocharger, which uses exhaust energy). This also helps improve volumetric efficiency at higher loads. It doesn’t change the engine’s displacement, it isn’t primarily about lean-burn fuel saving, and it doesn’t involve lowering the compression ratio.