The present invention provides a method for analyzing and optimizing the injection of fluid into an internal combustion engine via a common rail system. Once various injection parameters are determined for a given injection system, these data may be used to model the effect of sequential injection events for the system. A processer can then be used to run the model and to adjust sequential fuel injection events to optimize engine performance and fuel usage.

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.

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.

Disclosed is a method and a device for predicting the failure time of the pressure limiting valve of a high-pressure fuel pump of a motor vehicle. The method includes measuring a characteristic parameter of the pressure limiting valve each time the motor vehicle has been switched off, determining and storing a variable determined by using the measured characteristic parameter, determining the time profile of the variable determined from the characteristic parameter, predicting the future profile of the variable determined from the characteristic parameter, and comparing the predicted future profile of the variable determined from the characteristic parameter with a predetermined wear limiting value. The comparison is to predict the time at which the predicted future profile of the variable determined from the characteristic parameter reaches the predetermined wear limiting value.

A structure of a combustion chamber for an engine includes a crown surface of a piston, a combustion chamber ceiling surface, an injector and an ignition plug provided on the combustion chamber ceiling surface, and an intake opening and an exhaust opening opened in the combustion chamber ceiling surface. A side where the intake opening is opened is defined as an intake port side, and a side where the exhaust opening is opened is defined as an exhaust port side. An ignition portion of the ignition plug is disposed on the intake port side. The ignition plug is ignited at a timing after the piston passes a compression top dead center. The injector is disposed on the center portion, and is configured to inject fuel toward the exhaust port side. A cavity is provided on the crown surface. A reverse squish flow generation portion is provided in the combustion chamber.

A control device for controlling an engine provided with a fuel pump including a pressurizing chamber, a plunger inserted into the pressurizing chamber and which changes a volume of the pressurizing chamber, and an on-off valve configured to open and close a suction port, is provided. When a pressurizing cycle consists of a period of pressurizing stroke in which the volume of the pressurizing chamber is reduced to allow fuel to be pressurized and a period of suction stroke in which the volume of the pressurizing chamber is increased to allow fuel to be drawn into the pressurizing chamber, a closing cycle of the on-off valve is controlled so that a ratio of the closing cycle to the pressurizing cycle becomes smaller in a second combustion mode where a partial compression-ignition combustion is performed than in a first combustion mode where SI combustion is performed.

Various embodiments of the present disclosure are directed to methods of operating a spark-ignition internal combustion engine. In one embodiment, a method is disclosed including fuel is injected centrally into a combustion chamber via at least one fuel injection device per cylinder in at least one operating range of the internal combustion engine and is ignited centrally in the combustion chamber via at least one ignition device. The fuel is injected into the combustion chamber at an injection pressure of over 500 bar in the second half of the compression stroke before the top dead center of combustion and the internal combustion engine is operated at an air-fuel ratio 1.

In at least one operating range of the internal combustion engine, the fuel is injected into the combustion chamber between 180 and 0 before the top dead center.

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 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 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.