Methods and systems are provided for detection of a closing time for a solenoid valve. In one example, a method may include monitoring a current of the solenoid valve, filtering the current, and determining the closing time of the solenoid valve based on each of the current and the filtered current. In some examples, the solenoid valve may be an electrically-actuated fuel injection valve. In some examples, determining the closing time may include using the filtered current to determine an inflection point of the current.

Methods and systems are provided for detection of a closing time for a solenoid valve. In one example, a method may include monitoring a current of the solenoid valve, filtering the current, and determining the closing time of the solenoid valve based on each of the current and the filtered current. In some examples, the solenoid valve may be an electrically-actuated fuel injection valve. In some examples, determining the closing time may include using the filtered current to determine an inflection point of the current.

An injection control device for a fuel injection valve includes: a current detection unit, a current area correction control unit, a storage unit, and a reference current value correction unit. The current area correction control unit corrects, based on an energization current profile, an area correction amount of an energization time to equalize the integrated current value of the energization current profile and an integrated current value of the detected current, and obtains the integrated current value of the current based on an attainment time from a start of energization of the fuel injection valve to an attainment of each of plural reference current values. The storage unit stores a reference attainment time. The reference current value correction unit corrects each reference current value based on a difference between the reference attainment time and a detected attainment time at a time of actual drive.

An injection control device for a fuel injection valve includes: a current detection unit, a current area correction control unit, a storage unit, and a reference current value correction unit. The current area correction control unit corrects, based on an energization current profile, an area correction amount of an energization time to equalize the integrated current value of the energization current profile and an integrated current value of the detected current, and obtains the integrated current value of the current based on an attainment time from a start of energization of the fuel injection valve to an attainment of each of plural reference current values. The storage unit stores a reference attainment time. The reference current value correction unit corrects each reference current value based on a difference between the reference attainment time and a detected attainment time at a time of actual drive.

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.

A method is provided for determining the fuel temperature in the high-pressure zone of a fuel injection system of a motor vehicle. The fuel injection system has at least one injector operated by a servo valve which is actuated by means of a piezo actuator. After an injection process has been carried out, the piezo actuator is discharged after the injection has ended in such a way that the servo valve can close, but a non-positive connection remains between the piezo actuator and the servo valve. This condition of reduced charge is maintained. The pressure oscillation of the actuator voltage resulting from this is recorded and from this the hydraulic natural frequency of the enclosed high-pressure volume of fuel is deduced. The prevailing fuel temperature can be determined from the natural frequency.

A method for detecting defective injectors includes operating an internal combustion engine in an idling mode and deactivating mixture control of the internal combustion engine. The method also includes switching off selectively each injector of the respective injection group, detecting the change in the characteristic value when the respective injector is switched off, and checking a fault criterion. The fault criterion is satisfied when the change in the characteristic value for the respective switched-off injector exceeds or undershoots a predetermined amount. The method also includes detecting a defect in the respective injector in response to the fault criterion being satisfied.

A method for detecting defective injectors includes operating an internal combustion engine in an idling mode and deactivating mixture control of the internal combustion engine. The method also includes switching off selectively each injector of the respective injection group, detecting the change in the characteristic value when the respective injector is switched off, and checking a fault criterion. The fault criterion is satisfied when the change in the characteristic value for the respective switched-off injector exceeds or undershoots a predetermined amount. The method also includes detecting a defect in the respective injector in response to the fault criterion being satisfied.

A system and method for an electronic control unit adapter used to supplement existing electronic control units for enhanced or additional IO integration, the electronic control unit adapter designed to be updated easily by the end user in order to add functionality as it is developed thus prolonging the viability of an electronic control unit or vehicle, the electronic control unit adapter usable in conjunction with a vehicle or other vessel using an internal combustion engine or similar technology.

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.