An intake valve for a high pressure pump for internal combustion engine
fuel having a valve body having a seat with which cooperates a shutter
kept closed by a first spring of substantially constant pressure and by a
second spring varying in pressure during at least part of the stroke of
the piston. The springs are helical compression types and their pressures
are summed on the shutter, which has a plate and a stem. The first spring
is located between the valve body and a flange integral with a sleeve
fitted to the stem in an adjustable position. The second spring is
located between the plate and the piston.