A method of fuel injection rate shaping of the Diesel engine common rail fuel
system with common rail injectors and solenoid control is proposed. The
method envisages the impact on control current of impulses applied to the
control solenoid valve of the common rail injectors for variation of the
injection rate shape. At that, the fuel is supplied via two groups of
injection holes. The entering edges of the first group with the coefficient
of flow, ??B, were located in the sack volume and the entering edges of the
second group (coefficient of flow, ??H) - on the locking taper surface of
the nozzle body. The coefficients of flow, ??B, and ??H differ considerably
and depend on the valve needle position. This enables to adjust the
injection quantity by injection holes taking into account operating
conditions of the Diesel engine and hence - by the combustion chamber zones.
Using the constant fuel flow set-up, characteristic of the effective
cross-section of the common rail fuel system injector holes was
investigated. The diameter of injector holes was 0.12 ? 0.135 mm. The
excessive pressure at the entering edges varied from 30 to 150 MPa and more
and the excessive pressure in the volume behind the output edge - from 0 to
16 MPa.