Methods and systems are provided for reducing blackening of an oxygen sensor due to voltage excursions into an over-potential region. Before transitioning the sensor from a lower voltage to an upper voltage during variable voltage operation, an operating temperature of the sensor is reduced via adjustments to a sensor heater setting. The reduction in temperature increases the range of temperatures available to the sensor before the over-potential region is entered.

Controlling a fuel injector in a fuel system for an engine includes switching between a boosted voltage power supply and a lower voltage power supply during energizing a solenoid actuator in a fuel injector, and generating a solenoid energizing waveform including a pull-in tier produced by a boosted voltage incipient current, a boosted voltage second current, and a lower voltage later current, based on the switching between a boosted voltage power supply and a lower voltage power supply. Controlling a fuel injector further includes detecting an arrival timing of the valve based on a property of the lower voltage later current, and electronically trimming the fuel injector based on the detecting an arrival timing. Related control system logic is also disclosed.

The invention relates to a method for determining a characteristic value of a magnetic switch valve. The magnetic switch valve can be switched from a closed switch state into an open switch state, via the movement of a rotor by means of a switching magnet applied with current against a conservative restoring force. According to the invention, during the switching of the switch valve from the open state into the closed state, the time course of the current flowing through the switching magnet and/or of the voltage at the switching magnet is measured. The characteristic value to be measured is evaluated from this time course. It was recognised that every movement of the rotor against the switching magnet induced a voltage in same. Now the voltage at the switching magnet is regulated at a constant value, for one, the voltage induced by the movement can be observed as a control deviation in the short term. For another, the induced voltage causes a current flow through the switching magnets. Based on this, the kinematics of the rotor can be deduced. Given that the switching magnet has an ohmic resistance, energy is also dissipated via the current flow. This energy is the key to determining the switching path covered by the rotor when switching between the closed and the open state. The invention also relates to a measuring device that is particularly suitable for the method.

A fuel injection controller has terminals which can be connected to the coil of the fuel injector. A first valve-open control portion supplies the valve-opening voltage to the terminals for opening the fuel injector. The first valve-open control portion stops supplying the electric supply to the coil before the fuel injector is positioned at a full-open position. Before the fuel injector is fully closed, a small injection quantity can be obtained. A demagnetization portion forms a demagnetization circuit for demagnetizing the magnetism remaining in the coil. A normal-injection portion controls the fuel injector at full-open position.

Operating an engine system and fuel system includes energizing a solenoid actuator for a spill valve in a fuel injector in a first engine cycle via a standard waveform to inject a shot of fuel. Operating an engine system and fuel system further includes determining suitability for reduced energy operating of the fuel system, and energizing the solenoid actuator via a reduced energy waveform based on the determining suitability so as to inject one or more shots of fuel in a second engine cycle. The operating methodology and control logic can extend an engine speed range for multi-shot fuel injection in an engine.

Method for controlling a fuel injector with a piezoelectric actuator acting on a valve element, including the following steps, in the normal operation of the vehicle: (200): Estimating an engine parameter (Pj.sub.EST), representative of an actual play (J.sub.REEL) between the piezoelectric actuator and the valve element, (300): Comparing the engine parameter with the equivalent parameter (Pj.sub.ECU) representative of the original play (J.sub.INIT): if the engine parameter differs from the equivalent parameter in such a way that the actual play is greater than the original play: Applying an electrical polarization charge to the piezoelectric actuator, in order to polarize the piezoelectric actuator during the injection of the fuel, Commanding the closure of the injector.

Provided is a fuel control device for an internal combustion engine that is able to detect the correct boost voltage regardless of the temperature condition, and stabilize the boost voltage value, and is able to inject an accurate amount of fuel from a fuel injection valve. The boost voltage value detected when current is not flowing in a boosting capacitor at least during a boosting operation is taken as a legitimate boost voltage value, and this legitimate boost voltage value is compared with a prescribed boost voltage value to control the boosting operation. Thus, it is possible to stabilize the boost voltage at a legitimate boost voltage value regardless of the temperature condition, and it is possible to inject an accurate amount of fuel from a fuel injection valve, thereby improving fuel consumption.

Methods and systems are provided for injecting fuel through three different rows of injector nozzles, where each row of the injector nozzle is arranged along a different vertical plane of the injector body. In one example, an injector needle housed movably inside the injector body may supply high-pressure fuel to each of the rows of injector nozzles sequentially to deliver up to five fuel injections in one actuation cycle of the fuel injector. In another example, a fuel injector may include three injector needles, where movement of each injector needle inside a respective chamber of the fuel injector body may supply high-pressure fuel to the chamber from where the fuel may be injected through the coupled fuel injector nozzles.

An injection control device includes: an arithmetic unit that obtains a valve-closing time for stopping injection of fuel from a fuel injection valve based on a degree of variation in a time change of a voltage generated when the fuel injection valve is driven based on a required injection amount; an injection amount change unit that increases or decreases the required injection amount; and a learning unit that repeats injection control of the fuel to learn the valve-closing time obtained by the arithmetic unit.

An electromagnetically-activated actuator includes an electrical coil, an armature moveable between rest and actuated positions, and a bi-directional driver. A method for controlling an actuator event includes applying a supply voltage at a first polarity across the coil for a first duration to drive a forward current through the coil effective to move the armature away from the rest position. The forward current has a forward current peak at the end of the first duration. After the first duration, the supply voltage is applied at a second polarity across the coil for a second duration to drive a reverse current through the coil. The second duration terminates when the reverse current attains a predetermined reverse current peak, wherein the predetermined reverse current peak is coincident with the armature returning to the rest position.