| 摘要 |
PURPOSE:To provide a calculating circuit for use in an electronically controlled fuel injection system utilizing a hot-wire type flow meter as air-flow meter, which is capable of producing a standard fuel injection pulse proportional to the flow rate of intake air measured by the hot-wire type flow meter but inversely proportional to the revolutional speed of engine. CONSTITUTION:Input terminals of the first and the second switching circuits 1, 2, constituting a two-condition switching means, are connected to a dividing point (between R2 and R3) where output voltage of the emitter of transistor Q1 in a buffer amplifier consisting of resistance R1 and transistor Q1 and afforded with a signal representing the revolutional speed of engine is divided. Further, output voltage V of a hot-wire type flow meter (not shown) is impressed to tangential approximating circuit 3 constituting a charging control circuit via a buffer amplifier consisting of resistances R12, R13 and transistor Q8, and the collector of transistor Q9 in constant-current charging circuit 4 is connected to the output terminal of circuit 3. The collector of transistor Q11 in charging circuit 4 is connected to P- terminal of integrating capacitor C1, whereas Q-terminal of the capacitor C1 is connected to pulse generating circuit 7. |
