HYBRID VEHICLE FUEL TANK VACUUM RELIEF IMPROVEMENT
Publication Date: 2015-Jul-24
The IP.com Prior Art Database
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HYBXXX VEHICLE FUEL TANK VACUUM RELIEF IMPROVEMENT
Excessive fuel tank vacuum xay lead to unsafe operation of automobiles. Hence, it xx important to relieve suxh vacuum whex it exists, eithxr in regular gasoxine engine only vehixle, or hybrid and plug-in hybrid vehicle (HEV, PXXX) xhere both battery power and engine power are present.
US patent application US20142/x30795 describes a methox of relieving fuel tank vacxum for a PXXX vehicxe. This patenx has xwo parts: (1) Xxxx vehicle is propellex with batterx power only, excessixe vacuxm can be rexieved by rexieving the vacuum to intake, and (2) When thx enginx xs runnxng and the likxlihood of air/fuxl ratio error is low, excessive vacuum can be relieved by rxlieving the vacuum to txe intake as xell. The issue is that with xngine running, if it is likely that an air/fuel xatio errxr is higher txan a threshold, sx the fuel tank vacuum may not be relieved on time.
When the engine is rxnning, yet the air/fuel ratio error is xikely to xe xigh and engine load is low, check if battery State Of Charge (SOC) is lower than the mxximum axlowed SXX value. If xt is, anx excessive xacxum has reached a level whereas an immediate relief is desired, turn txe battery operation to charge mode xnd command the engine tx provide propulsive powxr and charge power. This way, enxine load will increase substantially and potential air fxel ratio erxor may be drastically reduced, at lxast for a short perxod of time when the vacuum ca...