Fig. 2.228. Camshaft phase regulator: 1 – phase regulator
To improve the filling of the cylinders with the working mixture in all modes, the K4M and F4R engines are equipped with a phase regulator of the intake valve camshaft (fig. 2.228).
The offsetting of the intake valve closing moment optimizes cylinder filling depending on the crankshaft speed. As a result, torque is increased in the medium-load mode and power at high crankshaft speed.
Under these conditions, later closing of the intake valves ensures the supply of an additional portion of the fuel mixture due to its high speed of movement.
On the contrary, at low rotation speeds the charge inertia is small. Earlier closing of the exhaust valves allows to avoid poor filling of the cylinders and loss of torque due to displacement of part of the fresh charge of the mixture.
The higher the crankshaft speed, the later the intake valves should close.