A method of controlling a fuel injection device that can control a small amount of injection is provided. A fuel injection device for use in an internal combustion engine, includes: a valve body that can open and close a fuel passage, a needle that transfers a force with the valve body, and executes valve opening/closing operation, and an electromagnet that includes a coil and a magnetic core provided as a driver for driving the needle, and a cylindrical nozzle holder disposed on an outer periphery of the magnetic core and the needle, in which a current is supplied to the coil to exert a magnetic attractive force between the magnetic core and the needle to open the valve body.

The invention relates to a control device applied to a cylinder injection type of an internal combustion engine (10). The control device control a disperse parameter for changing a degree of a spread of the fuel spray injected from the injector (20) such that the maximum degree of the spread of the fuel spray under a state where an amount of the fuel adhering to the spark generation part (31a) of the spark plug (30) at the ignition timing corresponds to a first amount, is smaller than the maximum degree of the spread of the fuel spray under a state where the amount of the fuel adhering to the spark generation part at the ignition timing corresponds to a second amount smaller than said first amount.

A fuel injection device is used in an internal combustion engine having a combustion chamber partitioned by a cylinder head, a cylinder, and a piston crown surface so that at least one of the amount of NOx, Pmax, and a thermal efficiency is maintained at a predetermined value. The fuel injection device includes a fuel injection change unit. The fuel injection change unit virtually divides the combustion chamber into N number of combustion zones where N is a natural number of 2 or more, and can change a fuel injection method according to the respective combustion zones. The fuel injection change unit divides the combustion chamber into the N number of combustion zones, thereby being capable of eliminating a difference of heat in the respective combustion zones, and precisely controlling an in-cylinder pressure P in the combustion chamber. As a result, the amount of NOx and the thermal efficiency can be optimized. Therefore, both of a reduction in the amount of NOx and the high thermal efficiency can be achieved.

A fuel injection device is used in an internal combustion engine having a combustion chamber partitioned by a cylinder head, a cylinder, and a piston crown surface so that at least one of the amount of NOx, Pmax, and a thermal efficiency is maintained at a predetermined value. The fuel injection device includes a fuel injection change unit. The fuel injection change unit virtually divides the combustion chamber into N number of combustion zones where N is a natural number of 2 or more, and can change a fuel injection method according to the respective combustion zones. The fuel injection change unit divides the combustion chamber into the N number of combustion zones, thereby being capable of eliminating a difference of heat in the respective combustion zones, and precisely controlling an in-cylinder pressure P in the combustion chamber. As a result, the amount of NOx and the thermal efficiency can be optimized. Therefore, both of a reduction in the amount of NOx and the high thermal efficiency can be achieved.

The invention relates to a method and a device for actuating an injection valve, which has a piezo actuator and a nozzle needle, of a fuel injection system of an internal combustion engine, in which method a control unit, in a manner dependent on a setpoint stroke height of the piezo actuator in successive injection cycles, outputs a control signal for changing the actual stroke height of the piezo actuator, characterized in that the control unit changes the setpoint stroke height of the piezo actuator, for compensation of the temperature dependency of the capacitance of the piezo actuator, in a manner dependent on the temperature of said piezo actuator.

A target injector valve opening period is calculated based on a target fuel injection amount, and an injector (2) is controlled by a current supply control unit (51) in accordance with an injector drive period acquired based on the target injector valve opening period. An actual valve closing delay period is calculated based on a drive waveform of the injector (2) at this time, and a difference between an actual valve closing delay period and a valve closing delay period calculated from a target injector valve opening period is learned. Then, the injector drive period is corrected by feedback control using a result of this learning.

A fuel injection control unit includes an injection amount detector and a correction unit. When implementing partial lift injection where a valve closing operation is started after the valve body starts a valve opening operation and before a valve body reaches a maximum valve open position, the injection amount detector detects a physical quantity (valve closing timing) having a correlation with an injection amount. When implementing the partial lift injection, the correction unit corrects an energization time of a fuel injection valve on the basis of a detection value (learning value) that was previously detected by the injection amount detector. An energization time in a small amount region longer than a predetermined time in the partial lift injection is allowed to be corrected on the basis of a value (small amount time detection value) detected in the small amount region by the injection amount detector. On the other hand, an energization time in an extremely small amount region shorter than the predetermined time is prohibited from being corrected on the basis of the above small amount time detection value. As a result, a precision in the injection amount in the partial lift injection is improved.

A fuel injection control unit includes an injection amount detector and a correction unit. When implementing partial lift injection where a valve closing operation is started after the valve body starts a valve opening operation and before a valve body reaches a maximum valve open position, the injection amount detector detects a physical quantity (valve closing timing) having a correlation with an injection amount. When implementing the partial lift injection, the correction unit corrects an energization time of a fuel injection valve on the basis of a detection value (learning value) that was previously detected by the injection amount detector. An energization time in a small amount region longer than a predetermined time in the partial lift injection is allowed to be corrected on the basis of a value (small amount time detection value) detected in the small amount region by the injection amount detector. On the other hand, an energization time in an extremely small amount region shorter than the predetermined time is prohibited from being corrected on the basis of the above small amount time detection value. As a result, a precision in the injection amount in the partial lift injection is improved.

An engine (1) includes an engine body, an injector (33), and an engine controller (100). The engine body includes a piston (15) inside a cylinder (11), and a combustion chamber (17) defined by the cylinder (11) and the piston (15). The injector (33) injects fuel containing at least gasoline into the combustion chamber (17) via a nozzle port (41). The engine controller (100) allows the injector (33) to inject the fuel in at least a second half of a compression stroke, and controls an injection condition of the injector (33). The injector (33) has a parameter for adjusting spread of fuel spray. The engine controller (100) adjusts the parameter to increase the spread of fuel spray with an increase in pressure in the combustion chamber (17).

An engine (1) includes an engine body, an injector (33), and an engine controller (100). The engine body includes a piston (15) inside a cylinder (11), and a combustion chamber (17) defined by the cylinder (11) and the piston (15). The injector (33) injects fuel containing at least gasoline into the combustion chamber (17) via a nozzle port (41). The engine controller (100) allows the injector (33) to inject the fuel in at least a second half of a compression stroke, and controls an injection condition of the injector (33). The injector (33) has a parameter for adjusting spread of fuel spray. The engine controller (100) adjusts the parameter to increase the spread of fuel spray with an increase in pressure in the combustion chamber (17).