This is a regulator, operated by a diaphragm,
which regulates the pressure of the fuel to 3 ± 0.2 bar.It is fitted on the fuel distribution pipe
and has the task of keeping the difference between the pressure
of the fuel and the pressure in the inlet manifold constant.In this way it is only possible to meter
the quantity of fuel to be injected on the basis of the injector
opening time.
Operation
When the pressure of the fuel exceeds the
maximum value, the diaphagm (1) intervenes on the valve (2) which
opens the return pipe to the tank.The spring (3) closes the valve (2) when
the pressure of the fuel returns below the maximum value.A pipe (4) connects the regulator spring
chamber to the air chamber.An interdependency is created through this
connection between the pressure of the fuel and the pressure of
the air; in this way the pressure between the injector inlet and
outlet is always the same when they are open.