🔍 Key Concepts

• diesel injection timing and how pressure builds in the injector system • the role of high‑pressure fuel lines and their physical properties • difference between combustion-related factors (compression, air temp, fuel quality) vs purely mechanical delay in injection

💭 Think About

• Ask yourself: which option directly affects how quickly fuel‑injection pressure rises enough to open the injector nozzle, before combustion even starts? • Which choices describe conditions inside the cylinder (combustion and ignition) rather than the mechanical/ hydraulic system that delivers the fuel? • Is injection lag about when fuel starts being injected, or about how easily it ignites once injected?

✅ Before You Answer

• Be clear on the difference between injection lag (delay between pump stroke and start of injection) and ignition lag (delay between injection and actual combustion). • Identify which answer choices would mainly change in‑cylinder combustion conditions vs those that change the fuel system’s pressure response. • Verify which factor would act like a "spring" or cushion, slowing the pressure rise in the fuel line before the injector opens.