🔍 Key Concepts

• Common rail fuel injection vs. traditional mechanical/unit injectors • How injection pressure and timing control affect combustion and emissions • Relationship between combustion quality, fuel use, smoke, and NOx emissions

💭 Think About

• For a common rail system, what can the electronic control of injection timing, duration, and pressure do to the combustion process compared to older systems? • If combustion is cleaner and more precisely controlled, how would that likely affect smoke throughout the load range? • Think about whether improved combustion control typically affects only one aspect (like smoke) or can influence fuel consumption, smoke, and NOx together.

✅ Before You Answer

• Compare how many benefits modern electronically controlled high‑pressure systems usually claim over older mechanical systems • Ask yourself if common rail systems are primarily marketed for just one performance gain or a combination of efficiency and emission benefits • Verify whether improved atomization and precise timing generally increase or decrease specific fuel consumption and visible smoke over the load range