An injection control device controls a solenoid in a fuel injection valve. The injection control device includes a transistor on an upstream side of a first power supply path to the solenoid, and a transistor on an upstream side of a second power supply path to the solenoid. The injection control device has another transistor with a body diode arranged in parallel at a position between an upstream terminal of the solenoid and ground. The injection control device also includes a transistor on the downstream side of the first and second power supply paths. A drive controller in the injection control device drives the solenoid to an open position by switching ON the transistor on the downstream side and one of the transistors on the upstream side power supply paths.

An operation coil drive device includes a drive control unit to perform control to set, for a semiconductor switching element to switch on and off the source voltage applied to an operation coil of a magnetic contactor, a larger ON/OFF time ratio for a circuit-closing control and a smaller ON/OFF time ratio for a holding control, wherein the drive control unit includes: a circuit-closing-control inductance calculation unit to calculate an inductance of the operation coil immediately after a start of the circuit-closing control; a circuit-closing-control resistance value calculation unit to calculate a direct current resistance value of the operation coil based on the calculation result; and a circuit-closing-control switching correction unit to correct the ON/OFF time ratio of the semiconductor switching element for the circuit-closing control based on the calculation result.

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.

A damper system may include an electrically adjustable hydraulic shock absorber having an electromechanical valve and a damper controller. The damper controller may include a solenoid driver circuit electrically coupled to the electromechanical valve, and disposed at the shock absorber. The solenoid driver circuit may be operable to drive the electromechanical valve in an open state in which hydraulic fluid flows between a pressure tube and a reserve tube. The solenoid driver circuit may include a plurality of transistors that are operable to generate a first current to place the electromechanical valve in the open state and a second current less than the first current to hold the electromechanical valve in the open state.

A solenoid system and method can include: providing an energizing voltage to a coil of a solenoid; providing an AC signal superimposed onto the energizing voltage; detecting current through the coil including an AC current amplitude induced by the AC signal and including a DC offset current amplitude; determining the AC current amplitude is a low AC current amplitude based on an armature within the solenoid being in a retracted position or determining the AC current amplitude is a high AC current amplitude based on the armature being in an extended position with the control logic, and where the AC current amplitude is determined utilizing the AC signal for synchronous demodulation; and determining a temperature fault based on the DC offset current amplitude falling below a DC offset current amplitude threshold.

A constant-current controller that supplies a constant current to an inductive load. This controller comprises an electric control circuit module. The electric control circuit module comprises a primary switch and a secondary switch. During a time interval in which the primary switch is closed (t.sub.on), the secondary switch is open and the voltage across the inductive load is equal to the source voltage (V.sub.s). At time t.sub.on until the end of a time interval (T), zero volts appears across the inductive load. During this interval, current continues to flow as supplied by the energy stored in the inductance. The periodic current in the inductive load becomes constant with a sufficiently large PWM switching frequency and is dependent upon the parameters of the control circuit and the duration of t.sub.on.

Various embodiments include a method for controlling a pressure dissipation valve comprising a closure element, a spring applying a spring force urging the closure element toward the closed position, and an electromagnetic actuator responding to an applied voltage to urge the closure element to an open position. The method may include: applying a constant voltage until the closure element begins motion counter to the spring force; immediately ending the voltage upon the beginning of motion; thereafter, applying a pulsed voltage to the actuator to induce a substantially constant holding-open current intensity; maintaining the pulsed voltage for a predetermined duration to hold the closure element open; and interrupting the application of voltage after the predetermined duration, wherein the closure element moves into the closed position as a result of the spring force.

An electromagnetic valve includes a valve body, a valve core, and an electromagnetic drive device. The valve body has an operation chamber, wherein the valve core is movably arranged in the operation chamber. The electromagnetic drive device is arranged in the valve core and is suitable for being electrically connected with a power source. The electromagnetic drive device is arranged, when driving the electromagnetic valve, to provide the valve core with a starting drive so as to drive the valve core to enter a running state. After the valve core is driven to enter the running to state, to provide the valve core with a maintaining drive so as to keep the valve core in the running state.

An injection controller has a voltage applicator that applies a voltage to a driving coil of an injection valve. After a voltage is applied to the driving coil with a peak current for opening the injection valve, the voltage applicator applies a power supply voltage to the driving coil in an ON-OFF manner, to supply the driving coil with a less-than-peak current. A comparator detects whether a terminal voltage at a terminal of the coil is less than a predetermined threshold voltage. Upon detecting that the terminal voltage is less than the threshold voltage, a discharge switch applies a boosted voltage to the driving coil.

A system can include an inductance module configured to operatively connect to a solenoid. The inductance module can be configured to input an AC excitation signal to the solenoid, determine and/or compare a current-voltage (CV) phase shift between a solenoid current and solenoid voltage, and output an output signal indicative of solenoid inductance based on the CV phase shift.