Flow rate supplement

Flow rate supplement

In order to facilitate both starting up the engine and the supply of full power, a system is fitted which, by altering the stroke of the pumping element pistons, allows an increase in the maximum fuel flow rate.

The three following operating modes are of special interest:

1. Operation during starting

Whilst the engine is being started up, the intake transfer pressure (1) is relatively low which allows the spring (2) to overcome the force exerted by the pistons (5) and extend in such a way as to move the sliding plates (3) outwards.

Under these circumstances the pistons (4) are in contact with the shorter side of the plates (3) with a consequent increase of the stroke and therefore also the value of the maximum flow rate.

2. Operation with turbocharger not operating

During normal operation, the intake transfer pressure (1) is greater than the opposing force exerted by the spring (2) and this allows the pistons (5) to move the sliding plates (3) inwards.

In this way the pistons (4) are in contact with the longer side of the plates (3) with a consequent decrease in the stroke and consequently the value of the maximum flow rate.

3. Operation with turbocharger working

The operation of the turbocharger causes an intake pressure (6) at the control valve (7) which causes the movement of an internal piston which places the transfer pressure inlet duct (8) in contact with the return ducts (9 and 10).

The decrease in pressure at the piston (5), allows the spring (2) to overcome the pressure of the inlet fuel (1).

The extending of the spring (2) causes the movement of the plates (3) with a consequent increase of the piston (4) stroke and the value of the fuel flow rate..