Does sulfur content of heavy fuel oil effect the fuel rate of a diesel engine and why or why not?

Correct Answer: Option C — Yes, high sulfur content decreases calorific value of fuel.

Higher sulfur content in residual heavy fuel oil displaces combustible hydrocarbons, directly lowering the lower heating value (calorific value) per unit mass. Consequently, more fuel mass must be injected to maintain equivalent thermal energy and engine power output.