The invention relates to a method (100) for operating a solenoid valve (1) for metering a fuel (2) in a fuel injection system (3). The solenoid valve can be actuated against a restoring force (12) by an electromagnet (11), wherein the time curve l(t) of the current I flowing through the electromagnet (11) and/or the time curve U(t) of the voltage U applied to the electromagnet (11) are detected during at least one opening process of the solenoid valve (1). The opening time t.sub.ON and the closing time t.sub.OFF of the solenoid valve (1) are evaluated (110) from the time curve I(t) and/or U(t), and the actual opening duration T.sub.T=t.sub.OFFt.sub.ON of the solenoid valve (1) is compared (140) with a reference value T.sub.R and/or the mass flow dm/dt flowing through the solenoid valve (1) is detected (120) and compared (142) with a reference value M.sub.R during at least one opening process of the solenoid valve (1); and/or a leakage dm/dt of fuel (2) through the solenoid valve (1) is detected (130) in the closed state of the solenoid valve (1). The invention also relates to a corresponding controller (5), a fuel injection system (3), and a computer program product.

In the present invention, a secondary pressure solenoid valve (74) for adjusting the pressure of oil supplied from an oil pump (70) so as to make the same an indicated pressure and a CVT control unit (8) for determining whether the adjustment operation of the secondary pressure solenoid valve (74) is normal are provided. This device for determining the normality of an electromagnetic control valve is provided with a secondary pressure sensor (82) for detecting the actual pressure arrived at through adjustment by the secondary pressure solenoid valve (74). The CVT control unit (8) uses a plurality of non-overlapping indicated pressure regions as determination regions for determining the normality of the adjustment operation of the secondary pressure solenoid valve (74). If the difference between the indicated pressure and actual pressure is determined to be less than a threshold in each of the plurality of indicated pressure regions, a determination is made that the secondary pressure solenoid valve (74) is normal. As a result, when determining whether the adjustment operation of an electromagnetic control valve is normal, it is possible to avoid erroneous determinations when a failure occurs and accurately determine the normality of the adjustment operation of the electromagnetic control valve.

A rotational angle determining device periodically samples a resolver signal output from a resolver receiving an alternating current excitation signal, the sampling being performed at a timing at which the excitation signal reaches a peak or trough value, based on a timer signal to which initial phase alignment is performed with respect to the excitation signal, and then the device performs A/D conversion of a voltage value of the sampled resolver signal, to determine the rotational angle of the rotor of the resolver. The excitation signal is periodically sampled at a predetermined timing based on the timer signal, and a presence or absence of a phase shift between the excitation and timer signals is detected based on a change in A/D converted value AD1n (n=1, 2, . . . ) obtained by A/D conversion of a voltage value of the sampled excitation signal.

A method for checking the operation of a high-pressure fuel supply unit for an internal combustion engine, consisting in driving a high-pressure fuel injection pump by a starter, and after the engine is synchronised and fuel injection into the cylinders is shut off, in defining an initial base pressure in a high-pressure rail, in activating the injection pump by issuing successive timing and angle-setting commands, on the basis of the initial pressure, and in comparing the first pressure and the second pressure obtained in the rail by these timing and angle-setting commands, and/or by comparing at least one of the pressures with a reference pressure in order to check the operation of the high-pressure fuel supply unit for the internal combustion engine.

An abnormality detection device includes: an opening degree acquisition unit, which acquires a plurality of opening degree data indicating an opening degree of a valve provided in a vehicle, the opening degree being measured during a certain period; an integration unit, which calculates an integrated value of a plurality of differences by integrating the plurality of differences between a plurality of opening degree actual measurement values indicated by the plurality of opening degree data acquired by the opening degree acquisition unit and an opening degree target value of the valve; and a determination unit, which determines that there is an abnormality in the vehicle when the integrated value integrated by the integration unit is higher than a certain value.

Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a high-pressure fuel pump operable to increase fuel pressure from a first pressure to a second pressure, a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors each of which is operable to inject fuel to individual cylinders of an engine, a pressure sensor operable to detect a pressure of fuel at the common fuel rail, and a controller operable to diagnose a condition of the high-pressure fuel pump based on output from the pressure sensor.

A variable valve, method, and diagnostic system are provided that determine accuracy of a position of a variable valve. The variable valve, method, and diagnostic system are configured to determine a system error, the system error being the difference between a commanded position of the valve and a measured position of the valve provided through a feedback signal of the valve. The variable valve, method, and diagnostic system are further configured to determine that a diagnostic accuracy passing condition is met if: a) the system error is less than a predetermined positive error threshold and greater than a predetermined negative error threshold; b) a rate of change of the measured position exceeds a predetermined positive feedback rate threshold; or c) the rate of change of the measured position is less than a predetermined negative feedback rate threshold.

Diagnostic systems and methods for a fuel system of an engine of a vehicle utilize a fuel rail pressure sensor, an engine speed sensor, an exhaust oxygen (O2) sensor, and a controller configured to perform a diagnostic routine for the fuel system during which fuel injectors of the fuel system do not need to be removed from the engine. The diagnostic routine comprises operating the engine at a set of predetermined operating points and detecting one or more malfunctions of one or more of the fuel injectors based on measured fuel rail pressure, measured engine speed, and measured O2 concentration at each of the set of predetermined operating points. Any fuel injector malfunctions detected during the diagnostic routine could be output to a diagnostic device operated by a human technician, e.g., in a single diagnostic report.

A method and apparatus for in situ operating an internal combustion engine comprising determining at least one combustion characteristic for a combustion chamber of the internal combustion engine, comprising an actual heat release signal for the combustion chamber; and inputting the actual heat release signal into a diagnostic logic tree for diagnosing changes in combustion characteristics due to at least one of: a malfunctioning fuel injector, a start of combustion timing error; and a change in fuel quality; and performing a mitigation technique to compensate for the changes in combustion characteristics.

An ECU that is a diagnostic device includes a calculation unit that is a water temperature obtaining unit obtaining the temperature of a discharge coolant which is a coolant discharged from an engine, a diagnostic unit that diagnoses a thermostat which is a temperature adjusting valve by comparing the temperature of the discharge coolant and a threshold, and a suspending unit that suspends a diagnosis performed by the diagnostic unit. The suspending unit suspends a diagnosis performed by the diagnostic unit in a case where the temperature of the discharge coolant is estimated to be lower than the threshold according to an operating condition of the vehicle even though the thermostat is normal.