Patent ID: 9696365
Date: 2017-07-04
CPC Classifications: B60L,G01R

Claim:
1. An electric leak detector for a vehicle, the electric leak detector comprising: a constant voltage control power source configured to be fed and driven by a battery so as to generate a control power supply voltage, the battery including a negative terminal connected to a vehicle body; a coupling capacitor including a first terminal and a second terminal, the first terminal being connected to a leakage detection target, the second terminal being connected to the constant voltage control power source; a repetitive signal output circuit connected to the second terminal of the coupling capacitor, and configured to repeatedly connect and interrupt the second terminal to and from the constant voltage control power source in an alternating manner, to thereby repeat a charge operation and a discharge operation of the coupling capacitor; a temperature detection section configured to detect a temperature of the coupling capacitor during the charge operation and the discharge operation of the coupling capacitor; a processor configured to execute a program; a memory that stores the program which, when executed by the processor, causes the processor to execute steps comprising: outputting a repetitive signal for switching between the connection and the interruption by the repetitive signal output circuit based on a voltage value of the second terminal; monitoring the repetitive signal to detect a charge period of the coupling capacitor; monitoring the repetitive signal to detect a discharge period of the coupling capacitor; calculating a repetitive signal charge-side leakage determination threshold for the charge period based on a voltage applied to the first terminal of the coupling capacitor and the temperature of the coupling capacitor detected by the temperature detection section; calculating a repetitive signal discharge-side leakage determination threshold for the discharge period based on the voltage applied to the first terminal of the coupling capacitor and the temperature of the coupling capacitor detected by the temperature detection section; comparing the charge period with the repetitive signal charge-side leakage determination threshold, and determining that a charge-side leakage occurs in the leakage detection target when the charge period is larger than the repetitive signal charge-side leakage determination threshold; and comparing the discharge period with the repetitive signal discharge-side leakage determination threshold, and determining that a discharge-side leakage occurs in the leakage detection target when the discharge period is larger than the repetitive signal discharge-side leakage determination threshold, wherein the calculating the repetitive signal charge-side leakage determination threshold comprises: increasing the repetitive signal charge-side leakage determination threshold when the voltage applied to the first terminal of the coupling capacitor increases or the temperature of the coupling capacitor increases; and decreasing the repetitive signal charge-side leakage determination threshold when the voltage applied to the first terminal of the coupling capacitor decreases or the temperature of the coupling capacitor decreases.