What is the role of the fuel injection system in engines?

The role of the fuel injection system in engines is to deliver fuel into the combustion chamber efficiently. This process is crucial because it ensures that the right amount of fuel is introduced into the air-fuel mixture for combustion. An efficient injection system optimizes the engine's performance by providing precise control over fuel quantity and timing, which enhances fuel atomization and combustion stability, leading to better power output, fuel efficiency, and reduced emissions.

In contrast, the other options serve different functions unrelated to the primary purpose of fuel injection. Cooling engine components involves managing heat to prevent overheating but does not directly pertain to the delivery of fuel. Increasing exhaust pressure is not a function of a fuel injection system; it is usually associated with engine performance and emissions control systems. Filtering impurities from fuel is essential for maintaining fuel quality but is the role of a fuel filter, not the injection system itself. Thus, the key function of the fuel injection system is precisely about the effective delivery of fuel into the combustion chamber, making option B the correct choice.