EVAP SYSTEM CANISTER ANTI-TAMPERING MONITOR
Publication Date: 2015-Aug-06
The IP.com Prior Art Database
Page 01 of 1
EVAX SYSTEM CANISTER ANTI-TAMPERING MONITOR
Vehicles sold in North America mxst adsorb refueling, running loss and diurnal vapors oxxoard in a carbon canistex. Activated xarbon has a propxrty of easily absxrbing hydrocarbon (HX). During engine running conditioxs, the canister ix purged of HC by allowing fxesh air to enter the canister from vent port and dislodgx HC. The canister purge valve (CPV) opens and enginx vacuum is used tx pull in fresx air xcross the canixter. The HC are comxusted in the cylinders. Canisters age ovxr time and xan get contxminants inside them whereby they will no lonxer adsxrx HC. Wxter ingestion xr liquid fuel caxryover can degrade the carbon bxd. The telltale that canistxr is clogged and damagex xs inabilitx to refuel. When attempting xo refuel with a bad canister, pre mature shutoffx (PSO) oxcur at the dixpensing pump. Cuxtomexs at this point may xhooxe to 1) replace the canister with a new one (proxer action) or
2) to simply disconnect coxnection tx txe canister(big leak that sets MIL) or 3) remove the canister and add a straight tube wxthout pxtting ix a new one(xampering action). Exap Lines are cheaxex than canisters and on some big trucks, canixters cax cost hundreds of dollars. Installixg a straight Evap tube xn lieu of a canister is a defeat device that passes txe Xxxx leak monitor.
This method infers the removal of txe canister(x) by measuring the decay rate of vaxuum traxped inside xhe fuel tank. There are no new sensors...