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:
Feb. 29, 2000
Filed:
Feb. 23, 1998
William D Meyer, Columbus, IN (US);
Cummins Engine Company, Inc., Columbus, IN (US);
Abstract
The present invention relates to a method and apparatus for control of current rise time during multiple fuel injection events. The invention utilizes a single boost voltage supply circuit, in which the boost capacitor is designed to store slightly more than twice the total energy required to pull-in a single fuel injector solenoid during the prescribed time. A reference waveform simulating the desired current rise time is compared to the actual boost voltage produced by the circuit. The boost voltage is modulated (switched on and off) in order to maintain the boost voltage within a predetermined window around the reference waveform. This modulation will compensate for any droop in boost voltage at the time of actuation, and will also compensate for two solenoids being actuated at the exact same time. It is only necessary that a nninimum amount of energy be stored in the boost capacitor at the completion of an actuation event, and the level of this minimum amount of energy can easily be determined by analysis or experimentation. Additionally, it is very easy to modify the shape and duration of the reference waveform, thus allowing for a very flexible solenoid drive circuit whose pull-in time and boost energy consumption can be easily changed to meet the requirements of an application without modifying the LRC time constants of the system.