Small Engine Parts And Functions Quiz! Trivia

In a 4-stroke-cycle engine, the intake stroke is the first stroke where the piston moves downward, drawing in a mixture of fuel and air into the combustion chamber. The compression stroke follows, where the piston moves upward, compressing the fuel-air mixture. Next is the power stroke, where the compressed mixture is ignited by a spark plug, causing an explosion that forces the piston downward with great force. Finally, the exhaust stroke occurs, where the piston moves upward again, pushing the burned gases out of the combustion chamber and through the exhaust valve.

In a 2-stroke-cycle engine, the crankshaft completes one revolution in a complete cycle. This is because the 2-stroke-cycle engine only requires two strokes of the piston - the intake/compression stroke and the power/exhaust stroke - to complete a full cycle. Therefore, the crankshaft only needs to rotate once to complete the cycle.

The crankshaft in an internal combustion engine converts the linear motion of the pistons into rotational motion. It has lobes, or offset sections, that act as counterweights. These counterweights help balance the forces generated by the piston movement and the explosions in the cylinders. The centrifugal force created by the rotating counterweights helps maintain the crankshaft's momentum, ensuring smooth and continuous rotation even when there's no direct force from the pistons, such as between combustion cycles.

The third key difference between diesel and gasoline 4-stroke-cycle engines is that diesel combustion occurs because of intense heat and pressure added to the fuel and air. This is in contrast to gasoline engines, which require a fuel injector to create the spark for combustion.

A 2-stroke-cycle engine is likely to be found on chainsaws and weed trimmers because these tools require a lightweight and compact engine that can provide high power-to-weight ratio. 2-stroke-cycle engines are known for their simplicity, low weight, and high power output, making them suitable for handheld tools like chainsaws and weed trimmers. They are less likely to be found on subcompact cars, Mazda RX-9, lawnmowers, or snowblowers, as these require larger and more complex engines.

A turbocharger or supercharger is a device that utilizes the exhaust gases to force more air into the cylinder. This process increases the amount of oxygen available for combustion, resulting in improved engine performance and power output. The turbocharger specifically operates by utilizing a turbine to harness the exhaust gas energy and drive a compressor, which then pressurizes the intake air. Similarly, a supercharger also increases air intake by using a belt-driven compressor. Both turbochargers and superchargers are commonly used in automotive engines to enhance their efficiency and overall performance.

In a 4-stroke-cycle engine, there are two revolutions of the crankshaft in a complete cycle. During the first revolution, the piston moves downward (intake stroke) and then upward (compression stroke). The second revolution involves the downward movement of the piston (power stroke) and then the upward movement again (exhaust stroke). This completes one cycle of the engine, and therefore, there are two revolutions of the crankshaft.

Air-cooled small gas engines are cooled by a combination of oil, fins, flywheel, and air. Oil helps to lubricate the moving parts of the engine and also aids in dissipating heat. Fins are designed to increase the surface area of the engine, allowing for better heat dissipation. The flywheel, which is attached to the engine's crankshaft, helps to circulate air and cool the engine. Lastly, air plays a crucial role in cooling the engine by carrying away heat from the engine's components. Therefore, all of the mentioned options contribute to the cooling process of air-cooled small gas engines.

The correct answer describes the function of a 2-stroke cycle engine. It states that the piston lowers, allowing the exhaust to exit the exhaust port just before the intake port opens. This creates a space for air/fuel/oil mixture to enter the cylinder. This explanation accurately describes the process of the intake and exhaust cycle in a 2-stroke engine.

The two parts of the camshaft are the timing gear and cam lobes. The timing gear is responsible for synchronizing the rotation of the camshaft with the crankshaft, ensuring proper timing of the engine's valves. On the other hand, the cam lobes are the raised, egg-shaped sections on the camshaft that interact with the engine's valves. As the camshaft rotates, the cam lobes push against the valves, opening and closing them at the correct intervals to allow fuel and air into the cylinders and exhaust gases out.