A current control device includes a target setting unit, a storage unit, an oil pressure ratio calculation unit, a specific current detection unit and a correction unit. The target setting unit adds a dither amplitude to a target current so that the current of the solenoid periodically changes at a dither cycle period longer than a PWM cycle period of the solenoid. The storage unit stores a stroke-current relationship between a stroke of the spool and the current of the solenoid. The oil pressure ratio calculation unit calculates an oil pressure ratio which is a value calculated by dividing an amplitude of the output oil pressure by an average value of the output oil pressure. The specific current detection unit detects a specific current based on the oil pressure ratio. The correction unit corrects the stroke-current relationship based on the specific stroke and the specific current.

A method for actuating an electromagnetic valve in a fluid system includes, for a specified first time period, a switching current with a specified first amplitude is applied, the switching current switching the electromagnetic valve from a rest state into a switching state. After the specified first time period expires, a holding current with a specified second amplitude is applied, the holding current holding the electromagnetic valve in the switching state. The first amplitude of the first switching current is greater than the second amplitude of the holding current.

A circuit for reducing a power consumption when driving a relay, the circuit includes a first input, a second input, a timing element, a longitudinal control having a Zener diode and a transistor, a first output, and a second output. The first and second inputs are configured to input an input voltage and the first and second outputs are configured for outputting an output voltage for driving the relay. The Zener diode is configured, when the input voltage exceeds a breakdown voltage of the Zener diode, to generate a voltage source, which is connected to the control input of the transistor via a diode and to provide a control voltage that is stabilized and reduced in level compared with the input voltage. The control input is connected to the first input via a timing element.

The present invention controls the pressure and flow rate of fluid, in order to obtain uniform performance, configure a closed loop magnetic circuit so as to include an electromagnet, a flapper, and a yoke material, and elastically deform the flapper itself by Maxwell attractive force generated between a magnetic pole of the electromagnet and the flapper to make the separation distance between the nozzle and the flapper variable. As opposed to a rigid flapper structure that swingably moves around a supporting point, like a conventional servo valve, the electromagnet, the magnetic pole, the nozzle, the flapper, and the like are arranged such that a change in magnetic gap directly leads to a change in air gap.

A latching valve has a valve body defining a fluid chamber and supply, delivery, and exhaust ports. A solenoid within the chamber includes a pole piece defining a fluid passage between the chamber and exhaust port and having one end facing the exhaust port and another end defining a first valve seat. A coil is disposed about the pole piece. A housing has a portion radially outward of the coil and portions extending radially inwardly on opposite sides of the coil radially aligned with the pole piece and an armature. The armature has one end configured for engagement with the first valve seat and another end configured for engagement with a second valve seat formed in the valve body between the fluid chamber and supply port. A return spring biases the armature towards the second valve seat. A magnet ring is disposed about the armature in contact with the housing.

A valve controller and method for controlling a valve having a solenoid are disclosed, including receiving a least one input signal, detecting a first edge of the at least one signal and in response to the detection activating the valve. Activating the valve includes activating the valve in a rise-to-peak phase during which the valve is opened, a hold phase following the rise-to-peak phase during which the valve remains open and a current level of the valve is less than a current level of the valve during the rise-to-peak phase, and an ending-of-activation phase following the hold phase during which current ripple in the valve is less than the current ripple in the valve during the hold phase.

The present disclosure provides a multi-stable solenoid with one or more magnetic damping rings. In general, the magnetic damping rings provide an increased damping force to an armature of the multi-stable solenoid to ensure efficient operation, reduce detent position overshoot, and reduce an impact force at end positions.

The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid injector that includes receiving a collection of waveform data, identifying a pull locus, determining a detection threshold level value, identifying a first subset of the collection of data representative of a selected first electrical waveform of the collection of electrical waveforms, identifying an opening value, identifying a representative closing value, identifying an anchor value, identifying a second subset of the collection of data based on the collection of data, the pull locus, the first subset, and the opening value, identifying a maximum electrical value, identifying an opening locus based the collection of data, the anchor value, and the maximum electrical value, identifying a hold value, and providing characteristics associated with the fluid injector comprising the pull locus, the opening locus, the hold value, the anchor value, and the representative closing value.

The present invention controls the pressure and flow rate of fluid, in order to obtain uniform performance, configure a closed loop magnetic circuit so as to include an electromagnet, a flapper, and a yoke material, and elastically deform the flapper itself by Maxwell attractive force generated between a magnetic pole of the electromagnet and the flapper to make the separation distance between the nozzle and the flapper variable. As opposed to a rigid flapper structure that swingably moves around a supporting point, like a conventional servo valve, the electromagnet, the magnetic pole, the nozzle, the flapper, and the like are arranged such that a change in magnetic gap directly leads to a change in air gap.

In one aspect, a solenoid tube for a solenoid is provided. The solenoid tube includes a unitary body, an inner surface on the unitary body, and a plurality of dimples formed on the inner surface. The unitary body defines a generally cylindrical shape and includes a first end and a second end. The inner surface extends between the first open end and the second closed end. The plurality of dimples extend radially inward from the inner surface of the unitary body.