US 6,904,893 B2Granted

Fuel injection method in fuel injector

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsYoshihiro Hotta, Yoshifumi Wakisaka, Kiyomi Kawamura, Kiyomi Nakakita

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Abstract

In fuel injector including an accumulator and an intensifier, fuel is injected such that an injection control valve and a piston control valve are individually controlled, an operational phase difference therebetween is regulated, and at least one of a maximum injection pressure, a rate of increase of an injection pressure at the start of an increase of pressure, a rate of decrease of the injection pressure at the completion of injection, a pilot injection pressure, and an after injection pressure of fuel injected from a fuel injection nozzle is arbitrarily changed. Namely, a pressure during a movement from a base common rail pressure of the accumulator to a static maximum pressure statically determined by an operation of the intensifier is positively used as a control factor of injection, whereby a fuel injection pattern can be implemented with an extremely high degree of freedom.

Claims11

Dependent claims

A fuel injection method in a fuel injection system, said fuel injection system comprising:

a fuel injection nozzle including a fuel reservoir and a needle valve;
an accumulator which accumulates fuel at a predetermined pressure;
a fuel line through which the fuel reservoir and the accumulator are connected;
a pressure cutoff valve which is provided along the fuel line, for cutting off fuel pressure flow from the fuel injection nozzle to the accumulator;
an injection control fuel chamber which is connected to the fuel line at a downstream side of the pressure cutoff valve;
an injection control valve which performs fuel injection by closing the needle valve due to an action of a fuel pressure upon the injection control fuel chamber and by opening the needle valve due to removal of fuel from the injection control fuel chamber;
an intensifier which is connected to the fuel injection nozzle and the injection control fuel chamber at a downstream side of the pressure cutoff valve;
and
intensifier control means which increases a fuel pressure at a downstream side of the pressure cutoff valve by operating the intensifier, said fuel injection method comprising the steps of:
suspending operation of the intensifier control means;
and
performing an after injection of fuel at an intermediate pressure between a predetermined pressure of the accumulator and a static maximum pressure which is statically determined due to operation of the accumulator and the intensifier.

9 more elements

Dependencies are inferred from the claim text.