Filing Information

Inventor(s)	Hisasi Kawai · Toshikazu Ina ·
Assignee(s)	Nippon Soken, Inc. ·  View assignee updates
Attorney/Agent(s)	Cushman, Darby & Cushman ·
Primary Examiner	Moose, Jr.; Harry E. ·
Application Number	US5874482
Filing date	02/02/1978
Issue date	04/03/1979
Predicted expiration date	02/02/1998
U.S. Classifications	361/152  · 361/154  ·
International Classifications	H01H 4704  ·
Kind Code	A
International Classifications	361152;153;159 ·
Foreign Priority	JP5213171 - 02/08/1977 ·

Patent Family

Abstract

In an apparatus for controlling an electromagnetic valve which is adapted for use with the fuel injection systems of internal combustion engines, after the expiration of a predetermined time the control of the energization of the electromagnetic coil of the electromagnetic valve is changed from constant-voltage control to constant-current control, and any surge voltage caused during the control change is selectively absorbed, thereby ensuring stable energization of the electromagnetic valve despite variations in the supply voltage or the like.

Independent Claims | See all claims (7)

1. 1. An apparatus for controlling an electromagnetic valve operable during energization of the electromagnetic coil thereof connected in series with a direct current power source through the emitter-collector path of a power transistor comprising:voltage control means connected to said coil and to the base of said power transistor for controlling the base current of said power transistor in response to changes in the voltage across said coil to thereby maintain a constant value of the voltage across said coil;current control means connected to said coil and to the base of said power transistor for controlling the base current of said power transistor in response to changes in the electric current flowing through said coil to thereby maintain a constant value of the electric current flowing through said coil;time control means connected to receive an input pulse signal having a pulse duration which determines energization duration of said coil for sequentially effecting control operations of said voltage control means and said current control means, said time control means effecting the voltage control operation of said voltage control means during a predetermined constant duration synchronized with and shorter than said pulse duration of said input pulse signal and than effecting the current control operation of said current control means during the remaining duration of said input pulse signal; andsurge control means connected to said coil for increasing the electric current flowing from said power transistor to said coil, cooperatively with said current control means, in response to a surge voltage produced by said coil upon the change from said voltage control operation to said current control operation.