🔍 Key Concepts

• diesel combustion phases (ignition delay, rapid pressure rise, controlled combustion) • how ignition delay affects how much fuel is in the cylinder before burning starts • difference between mixture properties (fuel/air ratio, CO₂, inflammability range) and timing of ignition

💭 Think About

• Which option directly affects how much fuel has accumulated and is ready to burn at the instant ignition actually begins? • If more fuel is injected but does not ignite immediately, what happens to the pressure rise once it finally does ignite? • Which choice is more about engine timing and combustion phasing rather than about exhaust gas composition or general fuel properties?

✅ Before You Answer

• Identify which choice relates to the time lag between start of injection and start of combustion. • Eliminate options that deal mainly with exhaust gases or broad fuel characteristics rather than the moment of ignition. • Focus on the factor that changes how suddenly the accumulated fuel burns, which directly affects the rate of pressure rise.