Inductive drive circuit for setting three different levels of load current including a downshift delay
Apparatus for controlling the operating current of electromagnetic devices Patent #: 4180026
ApplicationNo. 06/051588 filed on 06/25/1979
US Classes:361/154, Including means to establish plural distinct current levels (e.g., high, low)361/194Holding means
ExaminersPrimary: Moose, Harry E. Jr.
Attorney, Agent or Firm
International ClassesF02D 41/20 (20060101)
H01H 47/22 (20060101)
H01H 47/32 (20060101)
Foreign Application Priority Data1979-06-30 DE
AbstractA method is proposed for operating an electromagnetic load device with a movable armature, especially an injection valve of an internal combustion engine. The load device is supplied, at the beginning of trigger pulse, with a high amperage current and, at least toward the end of the pulse, with a reduced current. This method is characterized in that, starting with a certain amperage, at which preferably the armature is set into motion but has not as yet reached its final position, the current rise is at least reduced. The apparatus aspect comprises a measuring element and switching element connected in series with the load device. A threshold switch is associated with the measuring element to control the switching element. The switching thresholds of the threshold switch can be controlled in dependence on current and/or on time. The first current threshold is at a value at which the armature of the load is preferably being moved, but has not yet reached its final position. The method and the apparatus achieve a low power operation of the load device with a coincidence factor between the trigger pulse signal and, for example, the switching characteristic of an injection valve. It is essential that the current flow, after the starting current, no longer continue to rise in the same way but rather, if possible, is already somewhat reduced and, after the armature of the load has been attracted, a holding current is established as a function current and/or time. With a view toward a clear cut-out characteristic, a short term current supply to the load is advantageous at the end of the actual trigger pulse signal.