Question

which emissions system is designed to draw out blowby gases from the crankcase and send them back through the intake manifold?

a. egr
b. pcv
c. vvt
d. evap

Explanation:

• EGR (Exhaust Gas Recirculation): Recirculates a portion of exhaust gas back to the engine cylinders. It helps in reducing \(NO_x\) emissions by lowering combustion temperatures, not related to crankcase blowby gases.
• PCV (Positive Crankcase Ventilation): Designed to draw out blowby gases (gases that escape past the piston rings into the crankcase) from the crankcase and send them back through the intake manifold. These gases are then burned in the combustion chamber, reducing emissions.
• VVT (Variable Valve Timing): Adjusts the timing of the intake and/or exhaust valves. It improves engine performance, power, and fuel efficiency, not related to crankcase emissions.
• EVAP (Evaporative Emission Control): Controls evaporative emissions from the fuel system (e.g., fuel tank vapors). It captures and stores fuel vapors and then sends them to the engine for combustion, not related to crankcase blowby.

Answer:

B. PCV