| 摘要 |
PURPOSE:To make it possible to carry out the control of smooth speed change, by carrying out the control of speed change in accordance with a speed changing curve which is set such that an engine may be driven at a high heat-efficiency, in consideration with a range of variations in the rotational speed of a torque converter output shaft obtained based upon the difference between gear ratios of adjacent speed shift stages. CONSTITUTION:Output signals from a turbine rotational speed sensor (b) and an engine load sensor (g) are compared with a shift-down speed changing curve Ld that is set, on the low speed side, corresponding to one-half of a range (a+a) of variations in the output shaft rotational speed of a torque converter (a), which range is calculated in accordance with the difference between gear ratios of adjacent speed shift stages with respect to a turbine rotational speed v.s. engine load characteristic curve A along which an engine may be driven at a high heat efficiency, and a shift-up speed changing curve Lu which is similarly set on the high speed side. Therefore, whether shift-down or shift-up is necessary or not is determined. When judgement is made that it is necessary, a shift-down discriminating means (h) or a shift-up discriminating (i) delivers a shift-down instruction signal or shift-up instruction signal. |
