Fuel combustion control apparatus for engine

Claim 1

A fuel combustion control apparatus for an engine, comprising: (a) first detecting means for detecting engine operation conditions; (b) second detecting means for detecting engine knocking; (c) storing means, coupled to said first detecting means, for storing a regular map indicative of basic ignition advance angles with respect to engine operating conditions in use of regular gasoline, a highoctane map indicative of basic ignition advance angles with respect to engine operating conditions in use of highoctane gasoline, a reference map switching line indicative of standard ignition advance angles with respect to engine operating conditions along which the regular map is switched to the highoctane map, and a maximum highoctane map retard angle line with respect to engine operating conditions along which the highoctane map is switched to the regular map; (d) first commanding means, coupled to said first and second detecting means, for incrementing a current ignition advance angle in use of the regular map when said first detecting means detects engine operating conditions within a predetermined switching range and said second detecting means detects no knocking, and generating a first command to switch the regular map to the highoctane map only when the incremented ignition advance angle is equal to or larger than the reference map switching line and the maximum highoctane map retard angle line simultaneously; (e) second commanding means, coupled to said second detecting means, for decrementing a current ignition advance angle in use of highoctane map when said second detecting means detects knocking, and generating a second command to switch the highoctane map to the regular map only when the decremented ignition advance angle is smaller than the maximum highoctane map retard angle; (f) calculating means, coupled to said map storing means and said first and second commanding means, for selecting any one of the regular and highoctane maps in response to the commands from said first and second commanding means and for calculating actual ignition advance angles on the basis of basic advance angles stored in the selected map; and (g) means, coupled to said calculating means, for effecting fuel combustion on the basis of the ignition advance angle calculated by said calculating means.

Claim 6

A method of determining engine ignition advance angles on the basis of a regular map or a highoctane map, comprising the steps of: (a) checking whether engine speed lies within a predetermined switching range; (b) if engine speed lies out of the switching range, selecting the regular map; (c) if engine speed lies within the predetermined switching range, checking whether engine knocking is present or absent; (d) if present, decrementing the current ignition advance angle; and if absent, incrementing a current ignition advance angle; (e) checking whether the ignition advance angle is equal to or larger than a reference map switching line indicative of standard ignition advance angles with respect to engine speeds along which the regular map is switched to the highoctane map; (f) if smaller than the reference map switching line, selecting the regular map; (g) if equal to or larger than the reference map switching line, checking whether the ignition advance angle is equal to or larger than the maximum highoctane map retard angle line with respect to engine speeds along which the highoctane map is switched to the regular map; (h) if smaller than the maximum highoctane map retard angle line, selecting the regular map; (i) if equal to or larger than the maximum highoctane map retard angle, checking whether a predetermined time has elapsed; (j) if not elapsed, selecting the regular map; and (k) if elapsed, selecting the highoctane map.

Claim 7

A method of determining engine ignition advance angles on the basis of a regular map or a highoctane map, comprising the steps of: (a) checking whether engine speed lies within a predetermined switching range; (b) if engine speed lies out of the switching range, selecting the regular map; (c) if engine speed lies within the predetermined switching range, checking whether engine knocking is present or absent; (d) if present, decrementing the current ignition advance angle; and if absent, incrementing a current ignition advance angle; (e) checking whether the ignition advance angle is equal to or larger than a reference map switching line indicative of standard ignition advance angles with respect to engine speeds along which the regular map is switched to the highoctane map; (f) if smaller than the reference map switching line, selecting the regular map; (g) if equal to or larger than the reference map switching line, checking whether the ignition advance angle is equal to or larger than the maximum highoctane map retard angle line with respect to engine speeds along which the highoctane map is switched to the regular map; (h) if smaller than the maximum highoctane map retard angle line, selecting the regular map; (i) if equal to or larger than the maximum highoctane map retard angle, checking whether a predetermined time has elapsed; (j) if not elapsed, selecting the regular map; and (k) if elapsed, selecting the highoctane map.