Fuel injection controller

Abstract

In a case that actual values of a fuel injection quantity and fuel pressure are not in consistent with a representative point, an interpolation process is conducted by used of a learn value of a plurality of representative points. During the interpolation process, a computer determines whether the number of learning exceeds a predetermined number N. When the number of learning is less that the number N, the learn value at the representative point is replaced by the learning value at a representative point of the actual values.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like portions are designated by like reference numbers and in which:

FIG. 1 is a schematic structural diagram showing an engine system in a first embodiment of the present invention;

FIGS. 2A and 2B are time charts showing a transition of a rotation speed of each cylinder;

FIG. 3 is a block chart showing a control block for calculating a workload of each cylinder;

FIG. 4 is a time chart showing a rotation speed, a value corresponding to a current torque, and a workload of each cylinder;

FIG. 5 is a flow chart showing a calculating process of a learning value of each cylinder;

FIG. 6 is a chart showing a method for storing a learn value;

FIG. 7 is a chart for explaining an interpolating process by use of the learn value;

FIGS. 8A to 8C are charts for explaining problems in the interpolating process; and

FIG. 9 is a flowchart showing processes of a fuel injection control.

Claims

1. A fuel injection controller comprising: a learning means for learning and storing a deviation amount relative to a reference of an operational characteristic of an actuator, which is used for a fuel injection control for an internal combustion engine, as a deviation amount at a representative point with respect to each region which has been plurally divided with parameters used for the fuel injection control;an operating means for operating the actuator in such a manner as to compensate the deviation amount which is obtained by an interpolating process by use of the stored deviation amount in a case that actual value of parameters are consistent with no representative point;a determining means for determining whether the deviation amount converges at the representative point which is used for the interpolating process and is in a region where the actual value of parameters does not exist; anda substituting means for substituting the deviation amount at the representative point in a region in which the actual value of parameters exists for the deviation amount which has not converged in a case that the determining means determines that the deviation amount has not converged.

2. A fuel injection controller according to claim 1, wherein the determining means determines that the deviation amount has converged when a frequency of learning of the deviation amount at the representative point exceeds a predetermined number.

3. A fuel injection controller according to claim 1, wherein the actuator includes a fuel injection valve, andthe learning means includes a filtering means for filtering the rotation speed by a frequency which is defined based on a combustion frequency of the internal combustion engine in order to obtain a value corresponding to a current torque, and an estimating means for estimating a characteristic of each fuel injection valve based on the value corresponding to the current torque.

4. A fuel injection controller according to claim 3, wherein the internal combustion engine includes a multi-cylinder engine, anda reference of an operational characteristic of the fuel injection valve is established as an average fuel injection characteristic among each cylinder.

5. A fuel injection controller according to claim 3, wherein the parameters are comprised of a fuel pressure supplied to the fuel injection valve and a command value indicative of a fuel injection quantity to the fuel injection valve.