Internal-combustion engines – Engine speed regulator – Idle speed control
Reexamination Certificate
2000-02-09
2001-10-02
Kwon, John (Department: 3747)
Internal-combustion engines
Engine speed regulator
Idle speed control
C123S339120
Reexamination Certificate
active
06295966
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates an idling control system for an internal combustion engine of a type having two spark plugs by each cylinder.
In order to improve ignition performance and combustion speed of an internal combustion engine, various control systems have been proposed. Japanese Patent Provisional Publication No. 5-141336 discloses an engine control system for an internal combustion engine provided with two plugs for each cylinder. This conventional engine control system is arranged to select one of a one plug ignition mode and a two plug ignition mode according to the engine operating condition in order to improve a stability of engine combustion.
SUMMARY OF THE INVENTION
However, even when the two plug ignition mode is selected, two spark plugs of each cylinder are simultaneously ignited by this conventional engine control system. Although this simultaneous ignition timing effectively functions to ensure the stability of the engine combustion, the conventional engine control system still has a difficulty in satisfying both of increasing an engine torque and stably maintaining the engine combustion when the engine is operating in idling and when an engine speed is decreased due to an external load. More specifically, although the increase of the engine torque is ensured by advancing a simultaneous ignition timing of the two spark plugs, there is a possibility that the combustion becomes unstable due to the increase of time period for combustion stroke caused by the decrease of the engine speed. On the other hand, if the simultaneous ignition timing is retarded, the convergence of the engine speed to a target engine speed is delayed due to the shortage of engine torque although the combustion of the engine is maintained. Furthermore, when the engine is put in a lean combustion condition where an air-fuel ratio is set at a lean side as compared with a stoichiometric ratio (theoretical ratio) so as to improve fuel consumption, the above-mentioned trouble is significantly caused.
It is therefore an object of the present invention to provide an improved idling control system which preferably satisfies both of increasing an engine torque and stably maintaining the engine combustion when the engine is operating in idling and when an engine speed is decreased due to an external load.
An idling control system according to the present invention is for an internal combustion engine which has two spark plugs by each cylinder. The idling control system comprises an idling detector which detects that the engine is put in idling, an engine rotation speed detector which detects an engine rotation speed of the engine and a controller which is coupled to the idling detector and the engine rotation speed detector. The controller is programmed to decide on the basis of a engine rotation speed indicative signal of the engine rotation speed detector and an idling indicative signal of the idling detector whether the engine rotation speed in idling is smaller than an idling speed by a predetermined value and to differentiate ignition timings of the two spark plugs of each cylinder when the controller decides that the engine rotation speed in idling is smaller than the idling speed by the predetermined value.
REFERENCES:
patent: 6009851 (2000-01-01), Iida et al.
patent: 6092018 (2000-07-01), Puskorius et al.
patent: 6152105 (2000-11-01), Nishimura et al.
patent: 6209517 (2001-04-01), Yasui
patent: 5-141336 (1993-06-01), None
Foley & Lardner
Kwon John
Nissan Motor Co,. Ltd.
LandOfFree
Idling control system for internal combustion engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Idling control system for internal combustion engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Idling control system for internal combustion engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2604196