Controller and control method for injection using function map

Abstract

A method of controlling an injector or the like suitable for use in an internal combustion engine, includes providing a first data map having a plurality of first data map points, each of the first data map points representing a first data map output value, and providing a function map comprising a second data map having a plurality of second data map points, each corresponding to a respective one of the first data map points, and wherein the second data map is divided into at least a first-type data map region containing second data map points representing second data map output values only of a first type and a second-type data map region containing second data map points representing second data map output values only of a second type, wherein a portion of the second data map defines a hysteresis region. The method also includes determining an operating point on an operating path within the second data map in dependence upon first and second engine operating parameters and determining a control function for the injector based on a first data map output value determined from the first data map and the second data map output value determined from the second data map, in dependence upon whether the operating point in the second data map lies in a part of the first-type data map region which is outside the hysteresis region, or whether the operating point in the second data map lies in a part of the first-type data map region which is within the hysteresis region.