🔍 Key Concepts

• fuel injector cutaway – trace where the drilled passages start and end in the body • difference between supply line, return line, and internal cooling flow for a diesel nozzle • how continuous flow past hot parts can reduce nozzle tip temperature

💭 Think About

• From the illustration, where do the long drilled passages (arrows 19) connect at the top, and where do they emerge near the nozzle tip? • If fuel only needed to be delivered to the nozzle tip once, would you need two long parallel passages, or does that suggest a flow going down one way and back another? • Which option best matches a design where fuel is used itself as the cooling medium around a very hot nozzle tip?

✅ Before You Answer

• Identify whether the passages are clearly connected to a fuel inlet fitting or to a cooling water space • Check if there is any indication of a closed water jacket (for water cooling) or if all connections are fuel-related • Confirm whether the passages appear to form a circulating path around the nozzle tip rather than a single feed to or from the tip