What is the purpose of the compression stroke in an engine?

The purpose of the compression stroke in an engine is to compress the fuel/air mixture. During this phase of the four-stroke cycle, the piston moves up in the cylinder, reducing the volume of the cylinder and consequently increasing the pressure and temperature of the fuel/air mixture. This compression is critical as it prepares the mixture for ignition. A well-compressed mixture is essential for efficient combustion, leading to a more powerful and efficient engine operation.

In contrast, the other choices describe different strokes within the engine cycle. The drawing in of the fuel and air mixture occurs during the intake stroke, while the pushing out of exhaust gases happens during the exhaust stroke. Ignition of the fuel in the combustion chamber occurs during the power stroke, when the spark plug fires, igniting the compressed fuel/air mixture. Hence, each of these options refers to a distinct function, while the compression stroke specifically relates to compressing the fuel/air mixture.