: The Enlightenment during the 17th â 18th century produced philosophers and scientists who focused on human reason and rational thought to solve problems and provide ethnical systems for living. Enlightenment thinkers believed in natural over supernatural forces or laws.
A purge valve is the part of the vehicle Evaporative Emission Control (EVAP). system. The EVAP system prevents fuel vapors in the fuel tank from escaping into the atmosphere.
The generic term is or Pressure Relief Valve (PRV) or Pressure Safety Valve (PSV) Relief Valve (RV): automatic system that relief by static pressure on a liquid. It specifically open proportionally with pressure increasing.Safety Valve (SV): automatic system that relief by static pressure on a gas.he pressure is small and near the atmospheric pressure. Vacuum Pressure Safety Valve (VPSV): automatic system that relief by static pressure on a gas. The pressure is small, negative and near the atmospheric pressure.