| 摘要 |
PURPOSE:To simply and accurately detect a blown-out vent valve, by detecting period of fuel jet or ignition and taking a gate signal for blown-out pickup as a synchronizing reference signal. CONSTITUTION:When a fuel jet period detection signal from the 2nd acceleration meter 6 and a signal processing circuit 9 is applied as a synchronizing reference signal, a preset counter 10 counts a clock pulse is a frequency in response to the number of revolutions of the internal combustion engine with a tachometer 7 and a voltage-frequency converter 8. The counter 10 outputs a signal P2 when the specified preset value is coincident with the count value, i.e., blown-out start period, and sets the RS type FF12. This FF12 is reset with a preset counter 11 determining the gate period to control a gate circuit 14 in which an output of an acceleration sensor 5 inputs, which detects vibration or sound at the outside of vent pipes through the set output of the FF12. Thus, even if the number of revolutions of the internal combustion engine is changed, blown-out can simply and surely be picked up and detected without any encoder by taking the fuel jet period as a synchronizing reference. |
