| 摘要 |
PROBLEM TO BE SOLVED: To provide a detecting signal processing circuit for a common rail pressure to detect a fuel injection timing and a fuel injection amount at a low cost with high-precision by effecting analogue processing of a detecting signal for a common rail pressure without being directly digitalized and analogue- processed. SOLUTION: The pressure of a common rail 2 detected by a pressure sensor 11 has a high frequency component smoothed by a first smoothing circuit 42 and inputted to a differential circuit 43. When a differential signal Rd1 is reduced to a value lower than a preset differential value Rds, a comparator 44 outputs a first pulse signal Pco. The first pulse signal Pco related with the lowering timing of a common rail pressure is utilized for detection of a fuel injection timing. The voltage value of a signal Rs2 further smoothed by a second smoothing circuit 46 is converted into a frequency, i.e., the pulse width of a second pulse signal Pvf, by a V/F converter circuit 47 and utilized for detection of a fuel injection amount.
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