US 2006/0032297 A1Published application

Diagnostic apparatus for evaporative emission control system

AssigneeFuji Jukogyo Kabushiki Kaisha

InventorsYasushi Nakoji, Daisuke Takahashi

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Abstract

In a diagnostic apparatus for an evaporative emission control system having a fuel tank is hermetically sealed under negative pressure on the basis of target inner pressure, and leak of the evaporative emission control system is judged when a diagnosis value based on a pressure variation amount after the hermetical sealing under at least negative pressure is larger than a judgment value, ECU estimates an evaporated fuel generated amount on the basis of a tank inner pressure value at the start time of a diagnosis. When the evaporated fuel generated amount thus estimated is large, target inner pressure Pteb is set to a high value, and when the evaporated fuel generated amount thus estimated is small, the target inner pressure Pteb is set to a low value.

Claims6

Dependent claims

A diagnostic apparatus for evaporative emission control system having a fuel tank hermetically sealed under negative pressure on the basis of target inner pressure, for judging leak of the evaporated fuel when a diagnosis value based on a pressure variation amount after the hermetical sealing under at least negative pressure is larger than a judgment value, said diagnostic apparatus comprising:

an evaporated fuel generated amount estimating unit for estimating an generated amount of evaporated fuel in the fuel tank;
and
a target inner pressure setting unit for variably setting the target inner pressure on the basis of at least the generated amount of the evaporated fuel estimated by the evaporated fuel generated amount estimating unit, wherein the target inner pressure setting unit sets the target inner pressure to a higher value as the generated amount of the evaporated fuel is larger.

Dependencies are inferred from the claim text.