air intake so that they could be combined with the fresh air/fuel and more completely combusted. In 1961, California regulations required that all new cars be sold with a PCV system, therefore representing the first implementation of vehicle emissions control device. By 1964, most new cars sold in the U.S. were so equipped by voluntary industry action so as not to have to make multiple state-specific versions of vehicles. PCV quickly became standard equipment on all vehicles worldwide because of its benefits not only in emissions reduction but also in engine internal cleanliness and oil lifespan. In 1967, several years after its introduction into production, the PCV system became the subject of a U.S. federal grand jury investigation, when it was alleged by some industry critics that the Automobile Manufacturers Association (AMA) was conspiring to keep several such smog reduction devices on the shelf to delay additional smog control. After eighteen months of investigation, the grand jury returned a "no-bill" decision, clearing the AMA, but resulting in a consent decree that all U.S. automobile companies agreed not to work jointly on smog control activities for a period of ten years. In the decades since, legislation and regulation of vehicular emissions has tightened substantially. Most of today's gasoline engines continue to use PCV systems. Breather In order for the PCV system to draw fumes out of the crankcase, the system must have a source of fresh air. The source of this fresh air is the "crankcase breather", which is usually ducted from the engine's air filter or intake manifold. The breather is usually provided with baffles and filters to prevent oil mist and vapour from fouling the air filter. This phenomenon can be further reduced by installing after-market air oil separators or catch cans, as colloquially known, to pull oil mist out of suspension and collect it in a reservoir before it can reach the intake. A properly designed crankcase breather will also be designed in a manner that promotes the scavenging effect, or the creation of suction within the crankcase breather to further aid in the removal of blow-by gases. It is this effect that keeps the crankcase at slightly negative pressure when a properly functioning PCV system is in place. PCV valve Intake manifold vacuum is applied to the crankcase via the PCV valve. The airflow through the crankcase and engine interior sweeps away combustion byproduct gases. This mixture