| 摘要 |
PURPOSE:To control the fuel correctly irrespective of coil resistance changes due to an increase of temperature by connecting a current detection resistor to the solenoid coil of an injector in series and by controlling the valve opening work current and the closed valve holding current which flow through the coil based on the detection value. CONSTITUTION:When the voltage drop generated across a detection resistor 25 by the current I of a solenoid coil 1 is decreased down to about 0.15V, an FF10 is set by the output 3 from a comparator 14, turning the control transistor 2 on so that the current supplied by a power supply +B is gradually increased, and when the voltage drop reaches about 0.17V, the FF10 is reset by the output 2 of a comparator 13. Thereby, the transistor 2 is made off, then the current I generated by the back electromotive force of the coil 1 is decreased as it flows through the second short circuit consisting of a transistor 4, and these conditions are repeated in turn and continued until a repetition input signal Ti is reduced to zero. When the signal Ti becomes zero, the ransistors 2, 4 are both made off, thus the passage of the current I for the coil 1 is blocked, and the current I is blocked, and the current I is made zero. |
