Why will a turbocharged diesel engine produce black smoke if excessive additional load is applied too quickly?

Correct Answer: Option B — The inertia of the turbocharger rotor causes a time lag which delays the turbocharger speed increase.

Rapid load increases demand immediate fuel delivery, but the turbocharger rotor has physical rotational inertia. This mass creates a brief time lag before turbine speed and corresponding scavenging air pressure match the fuel input, causing temporary air starvation and black smoke.