| 摘要 |
PROBLEM TO BE SOLVED: To prevent the amplitude of vibration of a valve from being changed over the whole lift amount control region of a solenoid valve incorporated into a supply pump of a common rail type fuel injection system. SOLUTION: This duty ratio controller increases or reduces electromagnetic force generated in a coil of the solenoid valve by changing control frequency for duty ratio control between a first control region (a low load region of the solenoid valve, middle and high load regions of an engine) and a second control region (a high load region of the solenoid valve, idle operation and low load regions of the engine) while keeping on time per one control period in two first and second control regions at a fixed time to change the amount of lift of the solenoid valve. Consequently, even when the amount of lift of the solenoid valve is increased with the purpose for switching from the first control region to the second control region, a margin of change of amplitude of vibration of the valve can be suppressed to a small extent so that controllability of the flow rate of fuel passing through the inside of the solenoid valve can be improved over the whole lift amount control region of the solenoid valve. COPYRIGHT: (C)2007,JPO&INPIT
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