The VVT system changes phases of gas distribution of the camshaft of inlet valves, turning a camshaft asterisk in one or other party. It depending on power setting increases engine capacity, reduces fuel consumption and emission of the fulfilled gases.

Fig. 3.54. An arrangement of the regulating oil valve (OCV) in a back part of a head of the block of cylinders

The system turns on the block of control of the power transmission (PCM — Powertrain Control Module) adjusting the oil valve (OCV) (fig. 3.54) and knot of the pulley / drive of the camshaft of inlet valves.

The block of control of the power transmission (PCM) operates operation of the regulating oil valve (OCV) on the basis of information from the following sensors:

– sensor of speed of the car (VSS);

– sensor of provision of a butterfly valve (TPS);

– sensor of the measuring instrument of a consumption of air (MAP);

– sensor of temperature of cooling liquid (ECT).

The regulating oil valve (OCV) put in action by the block of control (PCM) increases or reduces pressure of the oil given to the pulley / drive of the camshaft of inlet valves.

The asterisk of the camshaft of inlet valves is equipped with the internal plug which is attached to the camshaft. The internal plug consists of a number of the fixed blades in such a way that pressure is used as a wedge for their turn and according to turn of the camshaft. At increase in pressure of oil, the camshaft angle of rotation increases.

At supply of oil to blades from an advancing the drive can turn the camshaft on a corner to 21 ° clockwise. When oil moves from delay, the drive will begin to turn a shaft counterclockwise to situation 0 ° advancings which are normal situation during the operation of the engine at an idling rotation frequency. The PCM block can also send a signal to the regulating oil valve to stop a stream of oil and to hold the camshaft in its current situation.

During the operation of the engine with small loadings the VVT system will reduce a camshaft advancing corner therefore the period of overlapping of valves will decrease and engine capacity is stabilized.

During the operation of the engine with average loadings the VVT system will increase a camshaft advancing corner to increase the period of overlapping of valves therefore engine capacity will increase and the amount of harmful substances in the fulfilled gases will decrease.

During the operation of the engine with big loadings with a low frequency of rotation of a bent shaft the VVT system will increase a camshaft advancing corner that were quicker closed inlet the valve therefore engine capacity at a low and average frequency of rotation will increase.

During the operation of the engine with big loadings with a high frequency of rotation of a bent shaft the VVT system will reduce a camshaft advancing corner to detain the moment of closing of inlet valves therefore engine capacity will increase.