| 摘要 |
PURPOSE:To simplify a complicated power transmission path, by estimating that a four wheel drive operation is required when the vehicle speed is lower than a predetermined value while the throttle valve opening degree is small so that a change-over mechanism is changed over from its four wheel drive condition to its two wheel drive condition in accordance with a predetermined change-over diagram. CONSTITUTION:In a control device for a vehicle four wheel speed change gear unit, in which solenoid valves 210, 220 are turned on and off, respectively, upon two wheel drive operation while both solenoid valves 210, 220 are turned off upon four wheel drive operation, upon operation of an engine E, an electronic control device 200 receives outputs from an output shaft rotational speed sensor 501, a throttle valve opening degree sensor 502 and a transfer shift lever position sensor 504. If a transfer shift lever is set at its H4 range, a change-over diagram having a change-over area with which the speed change gear is set to H2 when the outputs from the sensors 510, 520 are predetermined values, is read from a ROM. Further, when it is determined that the operation is in a change-over area in which the gear is changed-over to H2, the solenoid valves 210, 220 are turned on an off, respectively, to change-over the gear into the H2 range. |
