Power plants – Internal combustion engine with treatment or handling of... – By means producing a chemical reaction of a component of the...
Reexamination Certificate
1999-09-27
2001-01-16
Denion, Thomas (Department: 3748)
Power plants
Internal combustion engine with treatment or handling of...
By means producing a chemical reaction of a component of the...
C060S286000, C060S295000, C060S301000
Reexamination Certificate
active
06173570
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to exhaust gas purifying device or apparatus and process for an internal combustion engine equipped with an NOx trap catalyst.
Japanese Patent No.2692530 shows a control system for regenerating an NOx absorbing type catalyst by enriching an air fuel mixture temporarily and thereby releasing NOx from the catalyst in a reducing atmosphere. Japanese Patent Provisional Publication No. H7(1995)-332071shows a control system for controlling a direct injection gasoline engine to regenerate an NOx absorbing catalyst.
SUMMARY OF THE INVENTION
Enrichment of the air fuel mixture to desorb NOx from a catalyst can deteriorate the fuel consumption. In the case of a direct injection gasoline engine, enrichment in a compression stroke fuel injection tends to increase the possibility of misfire, and hence the enrichment can be achieved by changing the fuel injection timing to an intake stroke. In either case, the enrichment to release NOx constitutes a factor deteriorating the fuel economy and causing unwanted torque increase incurring the need for measures, such as retardation of the ignition timing, to prevent torque shock or torque fluctuation.
It is, therefore, an object of the present invention to provide apparatus and/or method for regenerating an NOx trap catalyst without deteriorating fuel consumption.
According to the present invention, an exhaust gas purification device for an engine, comprises at least a catalyst trapping and purifying NOx, an injector, a spark plug and a controller.
The controller is programmed:
to detect a catalyst regeneration condition for regenerating the catalyst by reducing NOx stored in the catalyst;
to calculate a first fuel injection quantity from fulfillment of the catalyst regeneration condition to the expiration of ;a first time period, the first fuel injection quantity being equal to or smaller than a stoichiometric fuel quantity required to set an average air fuel ratio in the combustion chamber equal to a stoichiometric air fuel ratio;
to calculate a first fuel injection timing based on the first fuel injection quantity, the first fuel injection timing being such a timing of fuel injection in the first fuel injection quantity on a compression stroke as to produce an air fuel mixture having a rich air fuel ratio in a limited region around the spark plug; and
to control the injector according to the first fuel injection quantity and the first fuel injection timing from the fulfillment of the catalyst regeneration condition to the expiration of the first time period.
According to another aspect of the present invention, an engine system comprises a direct injection internal combustion engine, a catalyst, an engine operating condition sensor; and a controller for controlling a fuel injection quantity and a fuel injection timing of the engine in a stratified charge combustion mode in a predetermined engine operating region, for monitoring the engine operating condition to detect a predetermined catalyst regeneration condition, and for changing an engine control mode, upon detection of the catalyst regeneration condition, from the stratified charge combustion mode to the catalyst regeneration combustion mode by increasing the fuel injection quantity from an ultra lean level to achieve an ultra lean target air fuel ratio for the stratified charge combustion mode to a non-rich level to achieve a non-rich target air fuel ratio equal to or leaner than a stoichiometric: air fuel ratio, and by holding the fuel injection timing on a compression stroke.
An engine controlling device according to the present invention may comprise:
means for calculating a first fuel injection quantity equal to or smaller than a stoichiometric fuel quantity required to set an average air fuel ratio in the combustion chamber equal to a stoichiometric air fuel ratio;
means for calculating a first fuel injection timing on a compression stroke so as to produce a limited region having an air fuel ratio richer than the stoichiometric air fuel ratio around the spark plug by fuel injection in the first injection quantity; and
means for controlling the engine according to the first fuel injection quantity and the first fuel injection timing from detection of a predetermined catalyst regeneration condition to the expiration of a predetermined time period.
An engine controlling process according to the present invention comprises:
calculating a first fuel injection quantity equal to or smaller than a stoichiometric fuel quantity required to set an average air fuel ratio in the combustion chamber equal to a stoichiometric air fuel ratio;
calculating a first fuel injection timing on a compression stroke so as to produce an air fuel mixture having a rich air fuel ratio richer than the stoichiometric air fuel ratio in a limited region around the spark plug by the fuel injection in the first injection quantity; and
controlling the engine according to the first fuel injection quantity and the first fuel injection timing from detection of a predetermined catalyst regeneration condition to the expiration of a predetermined time period.
REFERENCES:
patent: 5423181 (1995-06-01), Katoh et al.
patent: 5775099 (1998-07-01), Ito et al.
patent: 5910096 (1999-06-01), Hepburn et al.
patent: 5954023 (1999-09-01), Mizuno et al.
patent: 6003306 (1999-12-01), Kalversberg et al.
patent: 6032637 (2000-03-01), Mamiya et al.
patent: 6044642 (2000-04-01), Nishimura et al.
patent: 6058701 (2000-05-01), Mashiki
patent: 6073606 (2000-06-01), Shimizu et al.
patent: 7-332071 (1995-12-01), None
patent: 2692530 (1997-09-01), None
Ishihara Kouji
Mitsumoto Hisashi
Denion Thomas
Foley & Lardner
Nguyen Tu M.
Nissan Motor Co,. Ltd.
LandOfFree
Exhaust gas purification device 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 Exhaust gas purification device for internal combustion engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exhaust gas purification device for internal combustion engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2543615