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. 25, 1994
Filed:
Sep. 29, 1993
James C McCandless, Palatine, IL (US);
Navistar International Transportation Corp., Chicago, IL (US);
Abstract
A diesel engine hydraulically-actuated, electronically-controlled unit injector fuel injection system is provided with a two-stage pump system including two parallel pumps for supplying actuating fluid to the injectors. The first stage pump of this two-stage pump has a capacity which is adequate for most operating modes. The second stage pump is used for starting and for high engine load situations. The second stage pump is controlled by a solenoid bypass valve that switches in the second stage pump when the pressure in the high pressure rails fall below a desired or programmed level. An embodiment of this invention includes a second bypass circuit having a fast-response, solenoid-actuated bypass valve that bypasses all of the flow from both stages between injections and thereby produces a pulsed flow of actuation fluid to produce the required pressure for each engine fuel injection while unloading the pumping system between injections.