Various embodiments of the present disclosure relate to methods and systems for measuring an injected fuel quantity during multipulse injection events in a common rail of a fuel system including a fuel pump to supply fuel to the common rail. The method, using a control unit, determines if each of the multipulse injection events in a normal operating condition includes a pilot pulse; in response to determining that the pilot pulse is included, obtaining an enforced separation value between the pilot pulse and the main pulse to emulate a single-pulse injection; while the fuel pump is temporarily shut off, performing a temporary enforced separation on a fraction of the multipulse injection events; measuring a pressure change in the common rail during the temporary enforced separation; and resuming the normal operating condition of the multipulse injection events after the pressure change is measured.

A method for operating a fluid delivery system of a vehicle powerplant is provided. The method includes sampling a fluid pressure in a port injection section of the fluid delivery system, determining if an isolation valve positioned upstream of a direct injection pump is degraded based on the fluid pressure, where the isolation valve separates the port injection section from a direct injection section, and when it is determined that the isolation valve is degraded, indicating said degradation of the isolation valve.

An object of the invention is to reduce the amount of smoke generated and to improve the stability of diesel combustion in cases where an EGR apparatus is used in an internal combustion engine that performs diesel combustion using fuel having a relatively high self-ignition temperature. A control apparatus performs first injection at a first injection time during the compression stroke, causes spray guide combustion to occur, and starts to perform second injection at such a second injection time that causes combustion of injected fuel to be started by flame generated by the spray guide combustion, thereby causing self-ignition and diffusion combustion of fuel to occur. The apparatus changes the ratio of the first injected fuel quantity to the total fuel injection quantity and the ratio of the second injected fuel quantity to the total fuel injection quantity for the same total fuel injection quantity in one combustion cycle, based on the EGR rate in the intake air.

A method for operating a combustion engine is provided. A fuel injector is operated to perform a fuel injection, a sequence of pressure signals of the fuel rail pressure during the fuel injection is sampled and filtered and a total pressure difference between a first sample after a top dead center of the fuel pump and before the fuel injection has started and a chosen second sample after the injection and before a next pumping stroke is determined. A linear pressure slope at the second sample and a leakage pressure difference between the first sample and the second sample based on the linear pressure slope is calculated, leading to calculating an injection pressure difference as the difference between total pressure difference and the leakage pressure difference. With this, a value of a fuel quantity injected as a function of the injection pressure difference can be determined, while leakages are compensated.

An ECU as a valve body operation estimation device includes a sampling unit that obtains at least one of voltage and current of the electromagnetic coil as sample values at intervals of a predetermined time in a sampling period set based on a predetermined reference timing, a variation calculation unit that calculates a degree of variation of the sample values obtained in the sampling period, a variation waveform which represents a change of the degree of variation caused by shifting the reference timing including a point at which the degree of variation reduces and then rises as the reference timing is delayed, the point referred to as a rising start point, and a timing estimation unit that estimates an operation timing of a valve body based on the reference timing at the rising start point.

A method for correcting a deviation of static flow rates of GDI injectors is provided. The method includes calculating a target pressure drop amount for each cylinder and a relative pressure drop amount for each cylinder from a detected pressure drop amount. An injection correction factor for each cylinder is primarily adjusted by comparing the relative pressure drop amount for each cylinder, with an average of relative pressure drop amounts of all cylinders. The injection correction factor is then secondarily adjusted by comparing an average of injection correction factors of all cylinders with 1.

A fuel injection valve is for injecting fuel to cause combustion in an internal combustion engine. An injection rate adjuster is for adjusting an injection rate of the fuel injected by the fuel injection valve. A control device for the internal combustion engine includes a signal generator, and an outputter. The signal generator generates a command signal to cause the injection rate adjuster to adjust the injection rate based on a parameter, which is to estimate an internal EGR amount in which a part of exhaust gas remains in a cylinder. The outputter outputs the command signal to the injection rate adjuster.

An object of a control method to control a direct injection internal combustion engine that directly injects fuel in a cylinder is to reduce an increase in PN caused by attachment of the fuel to a fuel injection valve distal end. The control method cools the fuel before a fuel temperature when the fuel passes through an injection hole on a fuel injection valve reaches a temperature at which an amount of attached fuel to the fuel injection valve distal end increases.

A multi-cylinder engine includes a plurality of cylinders that are fired at uneven intervals. A controller is configured or programmed to overlap a time period that a plunger increases a pressure in a pressurizing chamber and a time period that an electromagnetic valve remains opened in at least the longest one of the intervals at which the firing is conducted in the plurality of cylinders.

A method and apparatus are disclosed for determining the fuel quantity that is actually injected by a fuel injector in an internal combustion engine. A fuel injector is operated to perform a fuel injection. The first discharge stroke of the fuel pump is deactivated following a start of the fuel injection for preventing the discharge stroke from delivering fuel into the fuel rail. A value of a pressure drop caused into the fuel rail by the fuel injection is calculated. A value of a fuel quantity injected by the fuel injection is calculated on the basis of the calculated value of the pressure drop.