FAA Powerplant Written Practice Test

During which stroke(s) does a continuous cylinder fuel injection system normally discharge fuel?

1. Only during the intake stroke

2. Only during the compression stroke

3. All continuously

4. Only during engine startup

The correct answer is: All continuously

A continuous cylinder fuel injection system is designed to supply fuel to the engine throughout the entire operating cycle, which includes all strokes of the engine. This method injects fuel continuously, ensuring that the mixture is readily available for combustion as the engine operates. By providing fuel at all times rather than at specific intervals, the system enhances performance, responsiveness, and efficiency. In contrast, other methods of fuel injection may only operate during certain portions of the cycle, such as just during intake when the intake valve is open. Continuous injection overcomes potential delays in fuel delivery that could occur in systems that inject fuel only during specific strokes, such as the intake stroke or engine startup, where maintaining optimal combustion conditions is critical for engine performance.