System VVT changes phases timing a camshaft of inlet valves, turning a camshaft asterisk in one or other party. It depending on power setting increases capacity of the engine, reduces the expense of fuel and issue of the fulfilled gases.
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Fig. 3.54. An arrangement of the regulating oil valve (OCV) in a back part of a head of the block of cylinders
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The system includes the block of the control of a power transmission (PCM — Powertrain Control Module), the regulating oil valve (OCV) (
fig. 3.54) and knot of a pulley / of a drive of a camshaft of inlet valves.
The block of the control of a power transmission (PCM) operates work of the regulating oil valve (OCV) on the basis of the information from following gauges:
– The gauge of speed of the car (VSS);
– The gauge of position throttle заслонки (TPS);
– The gauge of a measuring instrument of the expense of air (MAP);
– The gauge of temperature of a cooling liquid (ECT).
The regulating oil valve (OCV), put in action the control block (PCM), increases or reduces pressure of the oil submitted to a pulley / to a drive of a camshaft of inlet valves.
The asterisk of a camshaft of inlet valves is equipped by 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 accordingly camshaft turn. At increase in pressure of oil, the camshaft angle of rotation increases.
At oil giving to blades from outside advancings the drive can turn a camshaft on a corner to 21 clockwise. When oil moves from outside delays, the drive will start to turn a shaft counter-clockwise before position 0 an advancing which is normal position at engine work on frequency of rotation of idling. Block PCM can send also a signal to the regulating oil valve to stop a stream of oil and to keep a camshaft in its current position.
At work of the engine with small loadings system VVT will reduce a corner of an advancing of a camshaft therefore the period of overlapping of valves will decrease and capacity of the engine is stabilised.
At work of the engine with average loadings system VVT will increase a corner of an advancing of a camshaft to increase the period of overlapping of valves therefore capacity of the engine will increase and the quantity of harmful substances in the fulfilled gases will decrease.
At work of the engine with the big loadings at low frequency of rotation of a cranked shaft system VVT will increase a corner of an advancing of a camshaft that were fast closed inlet the valve therefore capacity of the engine on low and average frequency of rotation will increase.
At work of the engine with the big loadings at high frequency of rotation of a cranked shaft system VVT will reduce a corner of an advancing of a camshaft to detain the moment of closing of inlet valves therefore capacity of the engine will increase.