Internal combustion engine control apparatus
Because an in-cylinder temperature becomes low immediately after cold starting, it is impossible to take large ignition timing retard to avoid combustion instability and it takes time to activate a catalyst existing downstream of an internal combustion engine. The present invention provides an internal combustion engine control apparatus including an ignition timing control unit to control an ignition timing of an ignition device attached to an internal combustion engine. The internal combustion engine control apparatus includes an in-cylinder temperature raising unit that raises an in-cylinder temperature, the in-cylinder temperature is raised by the in-cylinder temperature raising unit, and a retard amount of the ignition timing of the ignition device is increased by the ignition timing control unit.
1. An internal combustion engine control apparatus comprising:
an engine control unit configured to perform an ignition timing control to control an ignition timing of an ignition device attached to an internal combustion engine, and
to perform an in-cylinder temperature raising control to
raise an in-cylinder temperature of a cylinder after a cold start of the internal combustion engine,
close an exhaust valve before a top dead center of an exhaust stroke and open an intake valve after the top dead center of the exhaust stroke, responsive to determining that a first predetermined time after start is reached, thereby providing a negative valve overlap (NVO) period where an exhaust is compressed,
gradually retard the ignition timing of the ignition device until a first predetermined ignition timing is reached; and
responsive to determining that a predetermined in-cylinder temperature or a second predetermined time after start is reached, retard further the ignition timing of the ignition device until a second predetermined ignition timing later than the first predetermined ignition timing is reached.
2. The internal combustion engine control apparatus according to claim 1 , wherein non-combustible gas is injected into a cylinder during the NVO period and a pressure in a combustion chamber is increased.
3. The internal combustion engine control apparatus according to claim 1 , wherein the in-cylinder temperature raising control is performed to set an intake valve closing timing to the vicinity of a bottom dead center to eliminate blow back to an intake pipe, in an intake stroke or a compression stroke.
4. The internal combustion engine control apparatus according to claim 1 , wherein the in-cylinder temperature raising control is performed to increase a mechanical compression ratio in a compression stroke or an exhaust stroke.
5. The internal combustion engine control apparatus according to claim 1 , wherein, during in-cylinder temperature raising by the in-cylinder temperature raising control of the engine control unit, the ignition control is performed to advance the ignition timing compared to an ignition timing during engine start and then to retard the ignition timing of the ignition device.