MDE 1 Q1 Exhuast Stroke

Answer: D) It maintains efficiency by ensuring complete removal of exhaust gases
Explanation: The exhaust stroke is crucial for maintaining engine efficiency because it clears the cylinder of exhaust gases. If exhaust gases are not fully expelled, they can dilute the fresh air intake, reducing the efficiency of combustion in the next cycle. Properly expelling the gases ensures that the engine operates efficiently.

Answer: C) To expel combustion gases from the cylinder
Explanation: The exhaust stroke is responsible for removing the combustion gases that remain in the cylinder after the power stroke. This expulsion ensures that the cylinder is cleared of exhaust gases, making room for a fresh charge of air during the next intake stroke.

Answer: C) It decreases as the piston moves upward
Explanation: As the piston moves upward during the exhaust stroke, the volume of the cylinder decreases, forcing the exhaust gases out through the open exhaust valve. This movement causes a reduction in pressure inside the cylinder as the gases are expelled.

Answer: A) Upward toward the cylinder head
Explanation: During the exhaust stroke, the piston moves upward toward the cylinder head, pushing the spent combustion gases out of the cylinder through the open exhaust valve. This upward movement helps to efficiently clear the cylinder of exhaust gases.

Answer: C) It channels the exhaust gases out of the engine
Explanation: The exhaust system is responsible for channeling the exhaust gases expelled during the exhaust stroke out of the engine. This system typically includes components like the exhaust manifold, muffler, and exhaust pipe, which work together to manage and direct the flow of exhaust gases away from the engine and the vessel.

Answer: C) The combustion gases will remain in the cylinder, causing poor performance
Explanation: If the exhaust valve fails to open, the combustion gases will not be expelled from the cylinder. This can lead to poor engine performance, as the remaining exhaust gases will reduce the amount of fresh air that can enter during the next intake stroke, leading to inefficient combustion.

Answer: B) Exhaust valve
Explanation: The exhaust valve opens during the exhaust stroke to allow the combustion gases to exit the cylinder and be expelled out of the engine through the exhaust system. The intake valve remains closed to prevent any backflow of gases.

Answer: B) Immediately after the power stroke
Explanation: The exhaust stroke follows the power stroke. After the fuel has been burned and the power stroke has pushed the piston downward, the exhaust stroke occurs to expel the remaining combustion gases from the cylinder.