π Key Concepts
β’ Four-stroke diesel cycle (intake, compression, power, exhaust) and what happens in each stroke
β’ What the camshaft physically looks like and how its lobes interact with other parts
β’ Difference between valves and fuel injectors in how and when they operate
π Think About
β’ In a four-stroke engine, which components must open and close at very specific crankshaft angles, and what mechanical part usually controls that timing?
β’ Which engine parts are typically operated by cams and followers (tappets, pushrods, rocker arms), and which parts might be driven in a different way?
β’ During one full four-stroke cycle, which items need repeated, timed actuation every cycle, and which might be actuated in another manner (e.g., by a pump or different drive)?
β
Before You Answer
β’ Be clear on the primary purpose of a camshaft: does it directly meter fuel, air, or just open/close something?
β’ Think about whether both intake and exhaust valves use the same operating system on a typical marine four-stroke diesel
β’ Consider how fuel injection timing and pressure are usually produced in a diesel: is it by the camshaft directly, or by another component that may or may not be cam-driven?