The present invention relates to a valve-moving control apparatus for intermitting operation of a predetermined number of valves of cylinders of an engine in accordance with a load applied to the internal combustion engine and a method therefor.
In an internal combustion engine for intermitting operation of a predetermined number of valves of cylinders in accordance with the load applied to the engine, when an opening degree of a throttle is low at a certain rotational speed, a large amount of axis torque output is obtained by intermitting actuations of some valves of the cylinders and when the open degree of the throttle is high at this rotational speed, a large amount torque output is obtained by actuating all valves.
Accordingly, a switch for intermitting actuations of some valves of the cylinders or actuating all valves is usually operated at a timing (cross point) when the torque output of an internal combustion engine in which some valves are intermitted, and the torque output of the engine in which all valves are actuated, are equal to each other at the same opening degree of a throttle as shown in FIG. 9. When the switch is shifted at the cross point, torque shock does not occur, since the torque output does not change.
However, if an internal combustion engine in which some valves of the cylinders are intermitted is changed to actuate all the valves, inner pressure at the intake pipe of all the cylinder is very high immediately after the operation is changed, and a large volume of air is suddenly intaken into all the cylinders, so that a large torque occurs and its shock is transmitted to an internal combustion engine's mounts, a driving mechanism and wheels of the vehicle in which the engine is mounted.
The shock caused by such a torque difference is not very much when a gear is shifted to high speed traveling such as the third, the fourth gear and the fifth gear, for which a gear change ratio is relatively low. On the other hand, the shock is largely transmitted to a chassis when the gear is shifted to a low speed traveling, such as the first or the second gear, for which the gear change ratio is large.