JPS6446056A - Driving device for engine accessory - Google Patents

Abstract

PURPOSE:To improve an accelerating property by switching over a speed change characteristic between the driving shaft and the driven shaft of an accessory driving device in accordance with the load condition of an engine and largely switching over deceleration at the time of accelerating and increasing the actual output of an engine. CONSTITUTION:At the time of a steady condition with the opening of a throttle valve 24 nearly constant, a change gear ratio characteristic is controlled to be a normal-time change gear ratio characteristic, whereas, when the opening of the valve 24 is rapidly increased with rapid increase in load, the rotating speed of a driving shaft is varied while the change gear ratio characteristic is controlled to be an accelerating-time change gear ratio characteristic. At this time, a target driven shaft rotating speed with respect to the rotating speed of a driving side pulley 5 is different from the present value. Therefore, a feeding oil pressure is increased by controlling a pressure control valve 18 and, on reaching a target value, a constant oil pressure, i.e., a constant change gear ratio is maintained. Thus, since the rotating speed of an accessory can be reduced reducing a driving loss rapidly by largely setting the change gear ratio, the actual output of an engine can be increased improving accelerating performance while suppressing the noise as well as the lowering of durability caused by the rapid increase in the rotating speed of the accessory.