Wire disconnection diagnosis apparatus of fuel injector drive circuit
AssigneeJapan Electronic Control Systems Co., Ltd.
InventorFujio Ono
Life of this patent
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Abstract
The present invention relates to an apparatus for diagnosing the presence or absence of a wire disconnection in a fuel injector drive circuit. When driving the solenoid of a fuel injector via a transistor by a drive pulse signal, the counter electromotive voltage used to turn off the transistor during a fall of a drive pulse signal is taken out and is charged to a capacitor included in the charge/discharge circuit. Also, the terminal voltage of the capacitor is determined during the rise of the drive pulse signal, and a wire disconnection is detected when the voltage is lower than a predetermined value. Further, a discharge of capacitor is started immediately after this determination, and a discharge of the capacitor is ended upon the fall of the drive pulse signal.
Claims3
A wire disconnection diagnosis apparatus for a fuel injector drive circuit, comprising:
- a fuel injector drive circuit for driving a solenoid in a fuel injector via a first transistor turned on by a drive pulse signal;
- a charge/discharge circuit charged by the counter electromotive voltage of said solenoid for turning off said first transistor during a fall of said drive pulse signal, said charge/discharge circuit being discharged upon the reception of a clear signal;
- a determining means for determining the charge potential of said charge/discharge circuit during the rise of said drive pulse signal and for detecting a wire disconnection when said potential is lower than a predetermined value;
- a discharge starting means for starting an output of said clear signal to said charge/discharge circuit immediately after the determination by said determining means;
- and
- a discharge ending means for ending said output of said clear signal during the fall of said drive pulse signal.
Dependencies are inferred from the claim text.