Question

The positive crankcase ventilation (PCV) system helps reduce _______ exhaust gas emissions. A. CO2 (carbon dioxide) B. HC (hydrocarbon) C. oxygen D. NOx (oxides of nitrogen)

Answer 1

Answer:

$\boxed{\text{B. HC}}$

Explanation:

The blow-by gases that escape past the piston rings and get into the crankcase are mostly unburned fuel-air mixture.

The fuel is largely a mixture of hydrocarbons (HCs) .

The PCV system captures these gases and feeds them back to the cylinder for further combustion.

A. is wrong. Carbon dioxide exits through the exhaust.

C. is wrong. Most of the oxygen in the incoming air is used for combustion in the cylinders.

D is wrong. The NOx gases exit via the exhaust and are trapped by the catalytic converter.