🔍 Key Concepts

• Identify from the illustration whether this is a large, medium-speed trunk-piston diesel or a very large slow-speed crosshead engine • Think about which starting methods are typical for medium-size marine diesels used on river push boats • Distinguish between direct air admission to cylinders and using an air or electric motor to crank the engine via the flywheel

💭 Think About

• From the cutaway, does the engine appear small/medium with a conventional flywheel and gear train, or a huge slow-speed main engine that would use separate air start valves in each cylinder? • If the starting air (if any) went directly into the cylinder, what extra valve or piping would you expect to see on the cylinder head that is separate from the fuel injector and exhaust valve? • Which system (air motor, electric motor, direct air) is simpler and more common for frequently started, medium-horsepower inland waterway engines?

✅ Before You Answer

• Look closely at the cylinder head in the illustration and see if you can clearly identify a separate air start valve with a supply line from an air manifold • Consider how often a river push boat starts and stops its engines and which system is most practical for that duty cycle • Before you choose, make sure you can explain to yourself how that starting system physically turns the crankshaft on this specific engine type