Boosting and performance – effect of supercharging For a given engine displacement, how does supercharging typically affect the power developed by the engine?

Introduction / Context:
Supercharging (and turbocharging) increases the density of the intake charge so that more air (and proportionally more fuel) can be burned per cycle. This is a fundamental method for specific power enhancement in both SI and CI engines.

Given Data / Assumptions:

• Same displacement and speed before and after supercharging.
• Boost pressure within mechanical and knock/combustion limits.
• Adequate intercooling or charge temperature management.

Concept / Approach:
Power is proportional to the mass of fuel burned per unit time and the efficiency of conversion. Supercharging raises manifold pressure, increasing trapped air mass. With proper fueling and control, this directly increases indicated mean effective pressure (IMEP) and brake power. Although there are additional losses (compressor work, heat), net power typically rises significantly.

Step-by-Step Solution:
Increase intake pressure → higher air density → more oxygen per cycle.Meter more fuel to maintain desired mixture or equivalence ratio.Higher charge → higher IMEP → higher brake power, subject to limits.

Verification / Alternative check:
Engine performance maps show strong correlation between boost and BMEP; turbocharged variants of the same base engine deliver substantially higher rated power.

Why Other Options Are Wrong:

• No effect contradicts the purpose of supercharging.
• Pure decrease ignores the fact that compressor work is outweighed by increased fuel energy release in practical designs.
• Efficiency may rise or fall depending on design; it does not “always” reduce.
• Exhaust temperature effects are secondary; the primary impact is on charge mass and power.

Common Pitfalls:
Overlooking detonation/knock limits in SI engines and peak cylinder pressure/thermal limits in CI engines; careful calibration and intercooling are essential.

Final Answer:
increases power output by raising the mass of charge inducted