The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 22, 2001
Filed:
Jan. 14, 2000
Christian Enderle, Baltmannsweiler, DE;
Andreas Hertzberg, Stuttgart, DE;
Klaus Roessler, Altbach, DE;
DaimlerChrysler AG, Stuttgart, DE;
Abstract
A method reduces harmful exhaust-gas emissions of a spark-ignition, direct fuel injection engine operated with a lean fuel/air mixture. Under part load, the engine is operated in the stratified-charge mode with a &lgr; value of >1, and to reduce nitrogen oxides adsorbed on a catalyst, a jump to a homogeneous mode with air ratios of lambda <1 is carried out at specific intervals by throttling of the air quantity supplied and/or by an increase in the fuel injection quantity. In a first step, the air quantity in the combustion space is reduced by changes in the valve control times and, in a second step, a transition is made from the stratified-charge mode to the homogeneous mode, with a &lgr; value of less than 1 being set.