Engine governing — qualitative vs quantitative (concept check) Evaluate the statement about qualitative governing: “In qualitative governing, the quantity of fuel is varied to suit the load on the engine and the total charge of air is altered.” Is this statement correct?

Introduction / Context:
Governing maintains engine speed under varying load. Two classic approaches are qualitative governing (altering mixture quality) and quantitative governing (altering total charge). Distinguishing these is essential in IC engine control theory and older carburetted systems.

Given Data / Assumptions:

• SI engines with carburetors exemplify qualitative governing.
• Load changes require either mixture strength changes or inducted charge changes.
• Modern EFI can emulate both strategies electronically.

Concept / Approach:
Qualitative governing varies the fuel-air ratio (mixture strength) while keeping the total inducted air charge approximately constant. Quantitative governing varies the total mass of charge admitted (by throttling or fuel quantity in diesels) while keeping mixture quality more nearly constant (stoichiometric in SI, excess air in CI). The statement mixes these and is therefore incorrect.

Step-by-Step Solution:
Define qualitative governing: adjust mixture richness/leaness at near-constant air charge.Define quantitative governing: adjust total charge mass at near-constant mixture quality.Compare with statement: it claims varying fuel and altering total air charge simultaneously under “qualitative,” which is inconsistent.Therefore, the statement is incorrect.

Verification / Alternative check:
Classic texts on carburation differentiate: qualitative (needle/jet control of richness) vs quantitative (throttle to change quantity).

Why Other Options Are Wrong:
Choosing “Correct” perpetuates the mix-up between mixture quality and quantity control strategies.

Common Pitfalls:
Assuming diesels use the same terminology; diesels primarily use quantitative control by varying fuel quantity at essentially unthrottled air.

Final Answer:
Incorrect