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:
Oct. 13, 1998
Filed:
Jul. 30, 1997
Yul J Tarr, Columbus, IN (US);
John D Crofts, Edinburgh, IN (US);
John T Carroll, III, Columbus, IN (US);
Laszlo D Tikk, Columbus, IN (US);
Cummins Engine Company, Inc., Columbus, IN (US);
Abstract
The improved needle controlled common rail fuel system of the present invention includes split common rails serving respective sets of unit injectors. Each unit injector includes a mechanically actuated plunger reciprocally mounted to cyclically create gradual periods of increasing pressure in the common rail during the advancement stroke of the plunger followed by respective periods of decreasing pressure during the plunger's retraction stroke. The fuel injectors include a pressure control valve for controlling the amount of fuel pressurized by the plunger and a needle valve control device including an injection control valve for creating an injection event during a pumping event by controlling the fuel flow to drain so as to control the fuel pressure forces acting on an injector needle valve element. A flow limiting device is provided to limit the fuel flow from a control volume to drain during an injection event thus reducing parasitic losses while maintaining quick valve closing. In addition, a pressure energy recuperation means is provided which utilizes the pressure of the fuel in each injector's pressure chamber as a result of the pressure energy stored in the fuel to assist in retraction of the injector plunger during each pumping event.