🔍 Key Concepts

• combustion process in a diesel cylinder right after injection and ignition • difference between fuel quality and fuel efficiency • how valve events (like overlap) affect breathing vs. combustion pressure rise

💭 Think About

• Ask yourself: what factor most directly changes how fast pressure builds up in the cylinder immediately after ignition, not how much air gets in overall? • Which option relates to the chemical and ignition characteristics of the fuel itself, rather than engine breathing or overall performance? • Consider which choice would most affect the timing and smoothness of combustion (e.g., delay period, rapid vs. slow burn).

✅ Before You Answer

• Separate in your mind engine breathing factors (air in/out) from combustion characteristics (how the fuel burns). • Check which option describes a property that could change the ignition delay and rate of energy release in the cylinder. • Before choosing, be sure you’re focusing on the moment right after injection and ignition, not on overall cycle efficiency.