Patent ID: 6100701
Filing Date: 2000-08-08
Classification: F02P

Abstract:
An electronic circuit (20) for detecting an error in the charging of an ignition coil (C1,C2) for a spark ignition engine, comprising: means (22,28) to measure the voltage (VB) of a battery for charging the coil (C1,C2); means (22,52) to determine according to the measured battery voltage (VB) a nominal dwell time (TC) for charging fully the coil prior to discharge of the coil; means (24,32,34) to measure an amount of current drawn by the coil (C1,C2) over a time less than the time taken to charge fully the coil (C1,C2); means (22,36) to extrapolate from the measured current a calculated expected dwell time (TD) to charge fully the coil (C1,C2); and means (22,44,62,64,66,68) to indicate an error condition if the difference (44) between the expected (TD) and nominal (TC) dwell times is beyond a predetermined error limit (58,60).