Evap system monitor inc 07 crossfire10/31/2023 ![]() In this saturated condition, the activated carbon cannot take on any more hydrocarbons, thus the hydrocarbons go into the atmosphere. The activated carbon will adsorb these fuel vapors until it becomes saturated. These hydrocarbons are caught in the cracks in the activated carbon when the fuel handling system is venting hydrocarbons under atmospheric pressure. The carbon canister provides a bed of activated carbon that allows absorption and desorption of the many different species of hydrocarbons, which are contained in gasoline. To trap the fuel vapor (gasoline), activated carbon is used ( Figure 1). In order to accomplish reduced hydrocarbons, the fuel handling and containment system was required to trap the fuel vapor and then pull this trapped fuel vapor into the engine to be burned. Since these pollutants, referred to as smog, are created in part by hydrocarbons in the atmosphere reacting with sunlight, it has become necessary to prevent these hydrocarbons from entering the atmosphere. Hotochemical smog is a type of air pollution caused by chemical reactions that occur between the sun’s ultraviolet light and pollutants, such as hydrocarbons and oxides of nitrogen. After CARB was established, the Environmental Protection Agency (EPA) was established in 1970 to regulate pollutants in the United States that harm human health.Īt first, these regulations covered the internal combustion engine’s tailpipe and crankcase emissions, and in 1970, moved to regulate the fuel handling and containment system (EVAP), which includes the engine’s tailpipe, crankcase emissions, and fuel vapor produce smog - an acronym for smoke and fog. This organization became the first to impose requirements on the automotive industry and still leads the nation on regulating vehicle pollutants. California established a new organization called the California Air Resource Board (CARB) in 1967.ĬARB is the “Clean Air Agency" of California. In order to control the air quality for human health, emission regulations were forced on the automotive industries. Why do we have EVAP systems on vehicles? In southern California, air quality became an issue in the mid 1960s. The third issue is the EVAP system is located from one end of the vehicle to the other end of the vehicle.Īll of these are serious concerns and will require you to have a great understanding of EVAP systems and the test equipment used in order to find these elusive leak sites.These small leaks can become large leaks with thermal expansion and contraction. You may think you will not need to find these small. The leak sites you must find are small at.The system test pressure is low at less than 1 psi.Small EVAP system leaks may be the most difficult to locate because of several issues: Finding these leaks can be time consuming and frustrating to say the least. ![]() Perhaps one of the toughest jobs in the automotive field is diagnosing small leaks, especially A/C and Fuel Vapor (EVAP) leaks. Some of the information may no longer be relevant, so please use it at your discretion. This article was originally published Oct.
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