🔍 Key Concepts

• Purpose of glow plugs in diesel engines • How engine size and speed affect starting characteristics • Differences between small, medium, and large diesel engines and their usual starting systems

💭 Think About

• Think about when cold starting is most difficult: which type or size of diesel engine typically needs extra help to ignite the fuel-air mixture? • Consider which engines might use air starting systems or heavy, residual fuels instead of needing glow plugs. • Look at each option and ask: does this type of engine more commonly rely on compression heat alone, or does it often need an added electrical heating element?

✅ Before You Answer

• For each choice, ask whether that engine type commonly uses air start vs. electric start. • Check which engines typically burn residual fuels and how they are usually started and preheated. • Focus on which engines are small enough and have an electric starting motor, making it practical to add glow plugs.