Patent ID: 6032637
Filing Date: 2000-03-07
Classification: F02D

Abstract:
An engine control system for controlling operation of an internal combustion engine in first and second injection modes in which fuel injection into a combustion chamber of the engine is made at different timings according to engine operating conditions, said engine control system comprising:speed detection means for detecting an engine speed;load detection means for detecting an engine load;memory means for storing a first engine control value map in the form of grid pattern which specifies continuous first engine control values corresponding to ones of engine speeds and engine loads at intersection points for a first range of ones of specified engine speeds and specific engine loads and a second engine control value map in the form of grid pattern, separated from said first engine control value map by a boundary, which specifies continuous second engine control values, discontinuous from said first engine control values, corresponding to ones of engine speeds and engine loads at intersection points for a second range of said ones of specific engine speeds and specific engine loads adjacent to said first range of specific engine speeds and specific engine loads, each one of said first and second engine control value maps specifying a virtual engine control value continuous from said engine control values of said each one of said first and second engine control value maps at a virtual intersection point in another one of said first and second engine control value maps for a specific engine speed and a specific engine load; andengine control means for controlling the engine with one of said first and second engine control values in one of said first injection mode and said second injection mode according to engine speeds and engine loads;wherein said engine control means, when a point in said grid pattern on which said detected engine speed and said detected engine load lie is further from said boundary than an extreme one of said intersection points closest to said boundary, determines an engine control value for said detected engine speed and said detected engine load by interpolation with said engine control values at said intersection points on both sides of said point of one of said first and second engine control value maps in which said point in included and, when said point is closer to said boundary than said extreme intersection point, determines an engine control value for said detected engine speed and said detected engine load by interpolation with said engine control value at said closest intersection point of one of said first and second engine control value maps and said engine control value at said virtual intersection point of another one of said first and second engine control value maps.