Which system provides fresh air to the cylinder to form the fuel-air mixture?

• A. Air intake system
• B. Exhaust system
• C. Cooling system
• D. Lubrication system

Answer: (A)

Fresh air must enter the cylinder to form the combustible fuel-air mixture, and that air is delivered by the air intake system. This system pulls in outside air, filters it to remove debris, and routes it through the throttle body into the intake manifold and cylinders. When the piston moves down during the intake stroke, air is drawn into the cylinder and mixed with injected or vaporized fuel to create the combustible mix.

The other systems don’t provide fresh air for the mixture: the exhaust system handles spent gases after combustion, the cooling system circulates coolant to control engine temperature, and the lubrication system distributes oil to reduce friction.