This invention provides two methods for detecting mechanical or electrical faults in a solenoid valve. In the first method, a force sensor is placed in the valve in such a way as to detect changes in the impact force of the plunger against the solenoid valve body or coil housing (depending upon the direction of movement of the plunger upon application of the electric current/magnetic field). A second method is provided which makes use of an accelerometer placed in such a way as to detect changes in the response of the plunger to the application of the magnetic field.

A method for switching over a solenoid valve having a movable valve body between a first position and a second position, wherein the method comprises at least the following method steps: a) adjusting a switching current to a pre-energization current intensity, in which the valve body remains in the present position, for a first time interval, and b) adjusting the switching current to a first switchover current intensity, which introduces a switchover movement of the valve body, for a second time interval.

A fuel system includes a fuel injector, and a fueling control unit electrically connected to a solenoid actuator in the fuel injector. The fueling control unit is structured to energize and deenergize the solenoid actuator to lift and return an armature coupled with an injection control valve. The fueling control unit also reenergizes the solenoid actuator with an armature retarding current while the armature is in flight to stabilize closing of the injection control valve. The armature retarding current can be used to electronically trim the fuel injector to limit an error in a quantity of injected fuel.

An actuation system to achieve soft landing and the control method thereof are provided. A soft landing is achieved via an open loop control of an electromagnetic actuator. The actuation system includes a control unit, wherein the control unit controls the electromagnetic actuator. The control unit does not rely on sensor data regarding a position of an armature to achieve the soft landing. As the actuation system achieves soft landing via the open loop control of the electromagnetic actuator by the control unit, a use of the sensor data is not needed.

Coil-based actuators for use in opening and closing the separable contacts of circuit interrupters provide increased initial velocity for opening strokes and improved damping at the end of opening strokes by utilizing current-based damping and omitting contact springs and contact dampeners.

A fuel system includes a fuel injector, and a fueling control unit electrically connected to a solenoid actuator in the fuel injector. The fueling control unit is structured to energize and deenergize the solenoid actuator to lift and return an armature coupled with an injection control valve. The fueling control unit also reenergizes the solenoid actuator with an armature retarding current while the armature is in flight to stabilize closing of the injection control valve. The armature retarding current can be used to electronically trim the fuel injector to limit an error in a quantity of injected fuel.

A hybrid relay (1) comprises an electromechanical part (10) with a movable contact (103), a solid state relay (11) and a control unit (2) for applying a drive signal (S′,S″) to the drivable coil (101) of the electromechanical part. A method for operating the hybrid relay comprises steps of determining a first minimum voltage (V.sub.1) for the drive signal above which the movable contact (103) starts to move away from an open position (P.sub.o) and a second minimum voltage (V.sub.2) for the drive signal above which the movable contact (103) reaches the closed position (P.sub.c), and a step of shaping a waveform (W) for the drive signal comprising a portion (W1) consisting of a vertical segment jumping from zero to the first minimum voltage value, a portion (W2) wherein the voltage gradually increases from the first minimum value to the second minimum voltage value, and a portion (W3) consisting of another vertical segment jumping from the second minimum voltage value to an upper voltage boundary (V.sub.sup).

A hybrid relay (1) comprises an electromechanical part (10) with a movable contact (103), a solid state relay (11) and a control unit (2) for applying a drive signal (S′,S″) to the drivable coil (101) of the electromechanical part. A method for operating the hybrid relay comprises steps of determining a first minimum voltage (V.sub.1) for the drive signal above which the movable contact (103) starts to move away from an open position (P.sub.o) and a second minimum voltage (V.sub.2) for the drive signal above which the movable contact (103) reaches the closed position (P.sub.c), and a step of shaping a waveform (W) for the drive signal comprising a portion (W1) consisting of a vertical segment jumping from zero to the first minimum voltage value, a portion (W2) wherein the voltage gradually increases from the first minimum value to the second minimum voltage value, and a portion (W3) consisting of another vertical segment jumping from the second minimum voltage value to an upper voltage boundary (V.sub.sup).

Provided according to the present invention is a solenoid with a built-in permanent magnet, with which it is possible to suppress an increase in the amount of magnetic flux that passes through the chuck part, even when the magnetic flux generated by a coil is greater than the magnetic flux of the magnet, and to reliably reduce attraction force. In this solenoid, a permanent magnet and a coil are both built into a cylindrical case having an opening part; the permanent magnet and the coil are both separated and arranged inside the case; a ring member is arranged adjacent to the permanent magnet; a movable iron core is inserted inside the coil; and between the movable iron core and the coil, a metal coil cover is provided so as to cover the coil. The distance d between the case inner wall and the ring member can also be in the range of 0.1-0.3 mm.

The electromagnetic relay includes a fixed terminal, a fixed contact connected to the fixed terminal, a movable contact piece moving in an opening direction and a closing direction with respect to the fixed terminal, a movable contact connected to the movable contact piece and being arranged to face the fixed contact, a coil generating an electromagnetic force to move the movable contact piece, and a drive circuit controlling a current to the coil. The drive circuit increases the current at a first increase rate in a first period that includes a period from a start time when the current starts to flow in the coil to before a contact time point at which the movable contact contacts the fixed contact. The drive circuit increases the current at a second increase rate larger than the first increase rate in the second period that includes a period after the contact time point.