Fuel pressure control apparatus for cylinder injection engine

A fuel pressure control, for cylinder injection engine comprising:

• fuel injection valve for injecting fuel into a cylinder of an engine;
• pipe for conducting said fuel to said fuel injection valve;
• a fuel pump for supplying said fuel from a fuel supply system into said pipe;
• a fuel pressure regulator for regulating the fuel pressure within said pipe by discharging said fuel from said pipe to said fuel supply system;
• and
• a control unit for controlling the fuel pressure within said pipe in a feed-back manner by supplying a control signal determined on an engine operation parameter to said fuel pressure regulator, wherein said control unit makes feed-forward control on said fuel pressure regulator according to a fixed value during at least part of a period in which the fuel pressure within said pipe transiently changes, wherein said control unit has feed-forward control means for controlling said fuel pressure regulator in a feed-forward manner by use of a certain control signal that causes said fuel pressure regulator to be substantially released from and the fuel within said pipe to be discharged into said fuel supply system when it is detected that the injection of fuel from said fuel injection valve is interrupted.

A fuel pressure control apparatus for cylinder injection engine comprising:

• a fuel injection valve for injecting fuel into a cylinder of an engine;
• a pipe for conducting said fuel to said fuel injection valve;
• a fuel pump for supplying said fuel from a fuel supply system into said pipe;
• a fuel pressure regulator for regulating the fuel pressure within said pipe by discharging said fuel from said pipe to said fuel supply system;
• and
• a control unit for controlling the fuel pressure within said pipe by supplying to said fuel pressure regulator a control signal determined on the basis of an engine operation parameter, said control unit comprising:
• fundamental control signal determining means for determining a fundamental control signal on the basis of said engine operation parameter;
• target fuel pressure determining means for determining the target fuel pressure within said pipe on the basis of said engine operation parameter;
• correction signal calculating means for calculating a correcting signal for correcting said fundamental control signal on the basis of the deviation between said target fuel pressure and the actual fuel pressure within said pipe;
• feed-back control means for making feed-back control on said fuel pressure regulator on the basis of a control signal obtained by correcting said fundamental control signal with said correction signal;
• transient change detecting means for detecting the transient change of the fuel pressure within said pipe;
• and
• feed-forward control means for making feed-forward control on said fuel pressure regulator on the basis of said fundamental control signal during the time from when the transient change is detected by said detecting means to when said transient change is removed.

A fuel pressure control apparatus for cylinder injection engine comprising:

• a fuel injection valve for injecting fuel into a cylinder of an engine;
• a pipe for conducting said fuel to said fuel injection valve;
• a fuel pump for supplying said fuel from a fuel supply system to said pipe;
• a fuel pressure regulator for regulating the fuel pressure within said pipe by discharging said fuel from said pipe to said fuel supply system;
• and
• a control unit for controlling the fuel pressure within said pipe by applying a control signal determined on the basis of an engine operation parameter to said fuel pressure regulator;
• said control unit comprising:
• fundamental control signal determining means for determining a fundamental control signal on the basis of said engine operation parameter;
• target fuel pressure determining means for determining the target fuel pressure within said pipe on the basis of said engine operation parameter;
• correction signal calculating means for calculating a correction signal for correcting said fundamental control signal on the basis of the deviation between said target fuel pressure and the actual fuel pressure within said pipe;
• feed-back control means for making feed-back control on said fuel pressure regulator on the basis of a control signal obtained by correcting said fundamental control signal with said correction signal;
• fuel cut detecting means for detecting that said fuel injection valve has interrupted fuel injection;
• and
• feed-forward control means for making feed-forward control on said fuel pressure regulator so that substantially the maximum amount of discharged fuel can be achieved when said fuel cut detecting means detects the interruption of fuel injection.