A lubricity estimation device is applied to a fuel supply system that supplies a fuel to an internal combustion engine, and includes a mixing ratio estimation unit and a lubrication index calculation unit. The mixing ratio estimation unit estimates the mixing ratio of each of plural types of molecular structures included in the fuel. The lubrication index calculation unit calculates a lubrication index, representing the lubricity of an outer peripheral portion S1 of the piston of a fuel pump and an outer peripheral portion of the valve body of a fuel injection valve by the fuel, based on the mixing ratio estimated by the mixing ratio estimation unit.

A method of determining one physicochemical parameter of a chemical agent in a fluid is provided the method comprising the steps of: providing a pressurized fluid of said chemical agent upstream of a dosing unit in a line; changing the opening condition of said dosing unit at a determinable time to to provide a dosing of said fluid or a change in the dosing of said fluid; determining the time, t.sub.p, at which the pressure wave in said line resulting from the pressure drop upon changing the opening condition of said dosing unit is detected at a known distance, d, from said dosing unit; determining the velocity of wave propagation from said time interval t.sub.pto and said known distance, d; and deriving the physicochemical parameter of said chemical agent from said velocity of wave propagation. The invention also pertains to a system for determining the physicochemical parameter of a chemical agent in a fluid, operating according to the same method.

A method for determining at least one injection parameter of an internal combustion engine, including the following steps: detecting a pressure profile in a time-resolved manner in an injection system of an internal combustion engine at least during an injection; providing a reference pressure profile for at least one operating point of the injection system; comparing the detected pressure profile with the reference pressure profile, and ascertaining at least one injection parameter as a function of the comparison.

An ECU functioning as a diagnostic device includes an information acquisition portion acquiring a flow rate of a fluid flowing through an intake pipe, and a diagnostic portion performing a diagnosis on a second purge pipe employed as a fuel gas pipe regarding a connection failure. The diagnostic portion diagnoses a connection failure of the fuel gas pipe according to magnitude of a pulsation of the flow rate acquired by the information acquisition portion.

A control device for an internal combustion engine includes a feel tank, a high pressure feel passage, a pressure increasing device, a switching device, a low pressure fuel passage, a temperature sensor, a fuel injector, and an electronic control unit. The electronic control unit is configured to determine that there is an abnormality in the switching device when a temperature measured by the temperature sensor when the pressure increase signal is output is not higher than a temperature measured by the temperature sensor when the pressure increase signal is not output. The electronic control unit is configured to stop fuel pressure increase by the pressure increasing device by stopping an output of the pressure increase signal regardless of the engine operation state when the electronic control unit determines that there is the abnormality in the switching device.

Methods and systems are provided for processing of an on-board diagnostic (OBD) test dataset, and transferring parameters of a curve fit to the processed data to an off-board location. In one example, a method may include performing an evaporative emissions system diagnostic test, fitting a curve to at least a part of the data, transferring parameters of the curve fit, along with the start, and end data points to an off-board location for further processing. The on-board controller may adjust engine operating conditions based on signal received from the off-board location after off-board data reconstruction, and analysis.

A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.

A vehicle includes an engine and a controller programmed to, responsive to an estimated oil dilution level of the engine exceeding a first threshold, issue commands such that regenerative braking is inhibited to increase a temperature of the engine, and responsive to the estimated oil dilution level falling below the first threshold, discontinue issuing the commands.

Control apparatus for an engine includes a failure determination unit which determines whether there is a failure in an operating engine, and an A/F (air-fuel ratio) feedback control unit which performs feedback control to bring actual A/F in the engine to a target set in advance. The failure determination unit includes a failure determination section, a failure code storing section, a similar operating condition recording section, and a return-to-normal control section. The A/F feedback control unit includes an A/F target setting section, and the target set is stored in the similar operating condition recording section as a factor defining the operating condition of the engine. The return-to-normal control section eliminates the failure code if the failure determination section does not determine that there is a failure when the engine is operating in an operating condition similar to that recorded in the similar operating condition recording section.

A control system for a watercraft includes a device on or in the watercraft, a sensor, and a computer. The sensor is operable to detect status data indicating a status of the device. The computer is configured or programmed to store a decision logic to determine whether or not a malfunction or trouble of the watercraft has occurred, and determine whether or not the malfunction or trouble has occurred based on the status data with reference to the decision logic.