| 摘要 |
PROBLEM TO BE SOLVED: To efficiently carry out pressure reduction of fuel pressure within a common rail while reducing processing load of a microcomputer. SOLUTION: In a common rail type fuel injection system, the microcomputer 151 generates drive signals of injectors 101 to 104 in response to an engine operation state, and determines whether pressure reduction of a common rail pressure is carried out or not. A drive circuit 100 turns ON transistors T10 to T40 and drives the injectors 101 to 104 based on the drive signals from the microcomputer 151. Upon request of cold blow from the microcomputer 151, the drive circuit 100 turns ON/OFF the transistors T10 to T40 in a small current region in which a fuel injection is not actually carried out, based on a current value flowing in a solenoids 101a to 104a of the injectors 101 to 104, and the cold blow by the injectors 101 to 104 is performed thereby reducing the common rail pressure.
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