Question

there are two primary pre - combustion emissions control systems: the ____ system and the ____ system.

a. exhaust intake recirculation; cooled air intake
b. heated gas recirculation; exhaust air intake
c. heated air intake; exhaust gas recirculation
d. none of the above

Explanation:

• Heated air intake: Helps in proper fuel - air mixture preparation before combustion.
• Exhaust gas recirculation (EGR): Recirculates a portion of exhaust gas back to the engine cylinders. This reduces the combustion temperature and the formation of nitrogen oxides (\(NO_x\)) which is a pre - combustion emissions control measure.

Answer:

C. Heated air intake; exhaust gas recirculation