| 摘要 |
PURPOSE:To reduce an error against an actual speed even when a speed has been varied remarkably like a car speed, by decreasing the hysteresis width of a hysteresis characteristic provided so as to shift a switching level of speed display at the time of acceleration and deceleration, in case when the extent of variation of speed has exceeded a prescribed value. CONSTITUTION:When detecting a speed which is varied remarkably like a car speed or an engine rotation speed, the extent of variation DELTAv of a car speed in 1 sampling period is calculated by comparing its sampling speed. Subsequently, whether¦DELTAv¦of this DELTAv exceeds a prescribed extent v0 (for instance, 2km/hr by 2 times of speed display unit) or not is decided. When it exceeds, it is decided to be a sudden acceleration or deceleration state, and a speed display signal inputted by an actual car speed display characteristic V(T)=V0[v(T)]is outputted. On the other hand, when said extent of variation is below the prescribed extent, it is decided to be a very small speed variation, subsequently whether DELTA is positive or negative is decided, a display car speed decided by an acceleration or deceleration characteristic is compared with a display car speed before 1 sampling period, and a larger or smaller car speed is outputted. In this way, since a hysteresis characteristic is varied in accordance with the extent of variation of speed, a speed display error against the actual speed is reduced. |
