Chapter 33, Problem 1RQ

Explain why a small PCV valve opening is adequate at idle speed.

To determine

The presence and importance of a small PCV valve opening is adequate at idle speed.

Explanation of Solution

A small valve opening as PCV is considered as satisfactory to run an engine at idle speed. These small valves help the engine to draw fresh air from the atmosphere through a filter cap which is vented. It helps in stopping the engine to release hydrocarbons directly to the atmosphere. When the vehicle is shut off, the excessive vapor present is forced out through the vent present at the oil filler cap. For a vehicle to run idle, a small opening is a must. PCV valve stops harmful emissions as it protects the environment from smog and other kinds of pollution caused by vehicle emission.

The PCV system works as there is a hole present inside the filtering source of air. Generally, this is provided by an engine air filter. This air helps in drawing the air from the crankcase, further it burns them into the engine. This extracts air from the crankcase and creates a vacuum inside the crankcase. PCV has helped in removing the extra pressure inside the crankcase. This helps in preventing leakage problems.

An absence of the PCV will cause contamination of the internal components of the engine. It will lead to sludge formation as the water and acid will be trapped inside the crankcase.