| 摘要 |
PURPOSE:To maintain the idling engine revolution at the optimum level by driving a step motor for flow control to the direction which would increase the flow path cross sectional area of a by-pass passage when the lubricating oil pressure of th engine falls below the predetermined pressure. CONSTITUTION:A step motor 9 which drives a flow control valve device 8 is connected to an electronic control unit 61 via a step motor drive circuit 60. When a signal from an oil pressure switch 67 which detects the engine lubricating oil pressure detects that the lubricating oil pressure is below the predetermined pressure the control unit drives the step motor 9 via the step motor drive circuit 60 to operate the flow control valve device 8 to increase the flow path cross sectional area of a by-pass tube 16 thereby elevating the target level of the engine idling revolution to prevent the reduction of the lubricating oil pressure. |
