Question 116Motor Plants - Assistant Engineer

The correct answer is D) the crown being tapered and smaller than the skirt. In large propulsion diesel engines, cast iron pistons are designed with a tapered crown, which is smaller in diameter than the skirt. This design feature helps to improve the piston's stability and reduce wear within the cylinder. The tapered crown allows for better control of the piston's movement and helps to distribute the forces more evenly, which is important for the durability and performance of the engine. The other options are incorrect because they do not accurately reflect the typical construction of cast iron pistons used in large diesel engines. A piston with no taper (option A), a skirt that is tapered and smaller than the crown (option B), or a skirt that is tapered and larger than the crown (option C) would not be the optimal design for this type of engine application.