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:
Aug. 06, 1991
Filed:
Apr. 25, 1990
Jeffery L Campbell, Hope, IN (US);
Lester L Peters, Columbus, IN (US);
Gary L Gant, Columbus, IN (US);
Leslie A Roettgen, Columbus, IN (US);
David P Genter, Columbus, IN (US);
Kevin R Wadell, Columbus, IN (US);
Cummins Engine Company, Inc., Columbus, IN (US);
Abstract
The present invention is directed to open nozzle type unit fuel injectors, and more specifically to an improved lower plunger and cup design of an open nozzle unit injector to minimize trapped volume and reduce unburned hydrocarbons in vehicle emissions. The lower plunger includes at least a major and a minor diameter sections with the minor diameter section extending within a bore of said cup at least partially between the fully advanced and retracted positions of the plunger. Moreover, the labyrinth flow area between the cup bore and the minor diameter section of the plunger is designed to reduce the trapped volume of fuel that results in the advanced plunger position while reducing sensitivity to fuel metering in the retracted plunger position. In one embodiment, the cup bore and minor diameter section are stepped. In another, both the bore and the minor diameter section are tapered. In yet another embodiment, only the cup bore is modified.