What is the purpose of an air filter in an engine?

The purpose of an air filter in an engine is essential for maintaining engine performance and longevity. The air filter serves to prevent dirt, dust, and other contaminants from entering the intake system of the engine. When clean air enters the engine, it is crucial for the air-fuel mixture that is needed for combustion. If dirt and debris were allowed to bypass the filter, they could cause wear and damage to the engine components, such as the pistons and cylinders, leading to reduced efficiency and premature engine failure.

Other options represent different functions that do not align with the primary role of the air filter. Increasing exhaust flow is related to components such as the exhaust system. Improving fuel combustion pertains more to aspects such as fuel injector performance and combustion chamber design. Regulating temperature is a function typically associated with the cooling system, rather than the air filter. Hence, the correct answer correctly identifies the primary role of the air filter in protecting the engine's internal components.