🔍 Key Concepts

• Detergent vs. non-detergent oils and what "detergent" additives are designed to do • Differences between trunk type diesel engines and crosshead diesel engines in how combustion byproducts reach the crankcase oil • Which systems require very clean oil with minimal additives (e.g., steam turbines, air compressors)

💭 Think About

• Ask yourself: In which engine design can combustion products (soot, acids, unburned fuel) most easily contaminate the crankcase oil? • Which application benefits most from an oil that can hold dirt, carbon, and sludge in suspension so they can be removed by filtration instead of depositing on parts? • Which of these systems is most sensitive to foaming, ash, and deposits and therefore usually uses very clean, low-additive oils rather than high-detergency oils?

✅ Before You Answer

• Identify which option involves a crankcase shared with the combustion space or close to it • Confirm which machinery (turbines, compressors, bearings) typically uses highly refined, low-additive, non-detergent oils for cleanliness and stability • Make sure the choice you pick is the one where piston deposits and soot control are a major concern