The VVT system changes phases of a gazoraspredeleniye of a 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 issue 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 a power transmission (PCM — Powertrain Control Module), the regulating oil valve (OCV) (fig. 3.54) and knot of a pulley / drive of a camshaft of inlet valves.

The block of control of a 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 a measuring instrument of a consumption of air (MAP);

– the 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 submitted to a pulley / drive of a camshaft of inlet valves.

The asterisk of a camshaft of inlet valves is equipped with the internal plug which is attached to a camshaft. The internal plug consists of a number of the fixed blades in such a manner that pressure is used as a wedge for their turn and respectively camshaft turn. 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 a camshaft on a corner to 21 ° clockwise. When oil moves from delay, the drive will start to turn a shaft counter-clockwise before situation 0 ° an advancing which is normal situation at operation of the engine on frequency of rotation of idling. The PCM block can send also a signal to the regulating oil valve to stop a stream of oil and to hold a camshaft in its current situation.

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

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

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

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