🔍 Key Concepts

• Diesel engine cylinder head components and how they appear in cross-section • Difference between an air start valve, fuel injector, and precombustion chamber • Where fuel injection actually takes place in an indirect‑injection diesel engine

💭 Think About

• Look closely at Figure D: where does the fuel spray go, and what kind of space or cavity does it enter first? • Compare Figure D with the other figures: which one shows only a valve body, which shows only an injector body, and which shows a separate small chamber connected to the main cylinder? • Ask yourself whether scavenging ports are usually found in the cylinder liner or in the cylinder head, and whether Figure D is a head or a liner view

✅ Before You Answer

• Identify if Figure D shows a small chamber separated from the main combustion space by a narrow passage or throat • Check whether you can see a valve spring and poppet valve for air admission versus just injector internals • Confirm whether scavenging ports are typically multiple slots around the liner rather than a single localized component in the head