🔍 Key Concepts
• diesel engine combustion process and the role of fuel injection timing
• how fuel spray pattern, droplet size, and penetration affect combustion
• relationship between when fuel is injected and how it burns in the cylinder
💭 Think About
• Ask yourself: if the fuel is injected at the wrong crank angle, which aspect of combustion (amount, speed, droplet breakup, or spread in the cylinder) will most closely mimic the symptoms of bad timing?
• Think about common symptoms of incorrect timing: knocking, high exhaust temperature, smoky exhaust. Which choice would typically create similar symptoms?
• Consider what "poor timing" really changes: is it mainly how much fuel gets in, how fast it goes in, how finely it is broken up, or where it ends up inside the cylinder?
✅ Before You Answer
• Be clear on the difference between quantity of fuel vs. distribution of fuel vs. atomization of fuel vs. rate of injection.
• Match each option to a specific, distinct problem (e.g., what happens if atomization alone is poor?).
• Before choosing, ask: which option would most strongly affect the start, duration, and completeness of combustion in a way that resembles incorrect injection timing?