Effect of Supercharging – Comparison with a Naturally Aspirated Engine (for the Same Power Output) Which statement best describes a supercharged engine compared to an ordinary naturally aspirated engine delivering the same brake power?

Introduction / Context:
Supercharging (or turbocharging) raises the intake density, permitting higher trapped mass per cycle. For a given required brake power, this allows a smaller displacement engine (and often smaller physical package) to achieve the target output, which affects weight, mounting, and installation design in vehicles and stationary plants.

Given Data / Assumptions:

• Comparison at identical brake power and similar technology levels.
• Properly matched supercharger/turbo with intercooling as needed.
• No abnormal derates or emissions constraints altering the baseline comparison.

Concept / Approach:

Because the boosted engine ingests denser charge, it can be designed with smaller swept volume and fewer cylinders for the same power. The result is lower engine block mass and smaller mounting footprint for equal output. While the supercharger/turbo adds components, the reduced core engine size typically more than offsets that mass, yielding a net lighter package per unit power. Lubricating oil consumption is not inherently reduced by boosting and may increase at high specific loads; thus the blanket claim of 'consumes less lubricating oil' is not generally valid.

Step-by-Step Solution:

Verification / Alternative check:

Specific power (kW per litre) increases strongly with boosting. Industry sizing rules for gensets and marine engines reflect smaller skid sizes for boosted units at given ratings.

Why Other Options Are Wrong:

'Consumes significantly less oil' is not generally true; 'must be heavier' ignores the displacement reduction; 'cannot deliver same power at lower displacement' contradicts the purpose of supercharging; 'always higher vibration' overgeneralizes—balance, mounts, and cylinder pressures govern vibration.

Common Pitfalls:

Assuming hardware mass alone decides weight; overlooking the large reduction in engine size when boosted.

Final Answer:

It is lighter and requires a smaller foundation for the same power output.