Abstract: A diesel engine comprises: a cylinder head covering one end of a cylinder; a piston having a crown surface opposed to the cylinder head, and performing a reciprocating movement within the cylinder; and a fuel injector attached to the cylinder head. The cylinder head is formed with an intake port so as to generate a swirl flow within the cylinder. The crown surface of the piston is formed with a cavity which is recessed toward an opposite side of the cylinder head and which has a circular shape in planar view, and a notch which is recessed radially outward from a peripheral edge of the cavity. The fuel injector is formed with an injection hole oriented toward an inside of the cavity.

Abstract: In a diesel engine, a crown surface of a piston is formed with a cavity which is recessed toward an opposite side of a cylinder head, and which has a circular shape in planar view, and a wall surface forming the cavity includes a lip which is formed on a peripheral edge of the cavity, and which is protruded radially inward, and the lip is formed with a plurality of notches which are recessed radially outward from the peripheral edge of the cavity, and a fuel injector is arranged at a center of the cylinder head, and formed with a plurality of injection holes oriented toward an inside of the cavity so as to radially spray fuel within the cavity, and each of the plurality of the notches is arranged between oriented directions of two adjacent injection holes.

Abstract: A control system that controls fuel injection of a diesel engine includes a split injection control module that causes a fuel injection valve to execute pre-injection for injecting fuel at a predetermined first timing, and post-injection for injecting fuel at a second timing later than the pre-injection, a setting module that sets a fuel injection amount or a fuel injection timing in the pre-injection or the post-injection so that a difference between a first peak and a second peak, which are peaks of an increase rate of combustion pressure accompanying the pre- and post-injection, falls within a predetermined range, and a calculation module that calculates the first and second peaks in an increase rate of the combustion pressure by excluding motoring pressure, which is an in-cylinder pressure at the time of non-combustion of the combustion chamber.

Abstract: The diesel engine is provided with a cylinder, a cylinder head, a fuel injection valve, and a piston. The piston has a cavity, and a notch formed in a circumferential edge of the cavity. The notch includes a first recessed portion which is recessed radially outward from an inner circumferential wall surface of the cavity, and a second recessed portion which is recessed from a crown surface of the piston toward a bottom side of the cavity and continuously extends radially outward from an end, on the crown surface side, of the first recessed portion. A vertical wall, on a downstream side of a swirl flow, of the second recessed portion is formed to extend, in an arched manner, radially inward and toward the downstream side of the swirl flow from a position corresponding to a radially outer side end of the second recessed portion in a plan view.

Abstract: A diesel engine comprises: a cylinder head covering one end of a cylinder; a piston having a crown surface opposed to the cylinder head and reciprocatingly movable in the cylinder; and a fuel injection valve attached to the cylinder head, wherein the crown surface of the piston is formed with a cavity which is concaved toward a side opposite to the cylinder head, and has a round shape in top plan view, and the fuel injection valve is formed with a nozzle hole directed toward the inside of the cavity, and wherein a wall surface defining the cavity has a wall segment formed in a periphery of the cavity at a position deviated from a directional direction of the nozzle hole and protruding toward a radially inward side of the piston in approximately parallel to a plane including a central axis of the piston.

Abstract: The diesel engine comprises: a cylinder head covering one end of a cylinder; a piston having a crown surface opposed to the cylinder head and performing a reciprocating movement within the cylinder; and a fuel injector attached to the cylinder head. The crown surface of the piston is formed with a cavity which is concaved toward a side opposite to the cylinder head and has a round shape in top plan view, and a groove concaved from a periphery of the cavity toward a radially outward side of the piston. The groove extends from the lower end on the side opposite to the cylinder head, toward the upper end on the side of the cylinder head, while inclining in a circumferential direction of the piston. The fuel injector is formed with a nozzle hole directed toward the groove.

Abstract: A diesel engine includes a cylinder, a cylinder head, a fuel injection valve, and a piston. The piston has a cavity recessed so as to be capable of receiving fuel injected from the fuel injection valve when the piston is positioned at a top dead center, and a notch formed by recessing a part of a circumferential edge of an opening of the cavity radially outward. The notch inclines radially inward at an angle of 0° to 50° relative to a center axis of the cylinder from a piston crown surface toward an inner circumferential wall surface.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; a low-pressure EGR passage connecting a part of the exhaust passage downstream of the turbine to a part of the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area of the low-pressure EGR passage; an exhaust shutter valve disposed downstream of the connected part of the exhaust passage to the low-pressure EGR passage, and for changing a cross-sectional area of the exhaust passage; a valve control device for controlling openings of the low-pressure EGR valve and the exhaust shutter valve; and a gear range detector for detecting a gear range of a transmission of a vehicle in which the engine is installed.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; a low-pressure EGR passage connecting a part of the exhaust passage downstream of the turbine to a part of the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area of the low-pressure EGR passage; an exhaust shutter valve disposed downstream of the connected part of the exhaust passage to the low-pressure EGR passage, and for changing a cross-sectional area of the exhaust passage; a valve control device for controlling openings of the low-pressure EGR valve and the exhaust shutter valve; and a gear range detector for detecting a gear range of a transmission of a vehicle in which the engine is installed.

Abstract: A wall shape of a cavity consists of an inward protruding portion located at the periphery of an opening, a center portion projecting toward a fuel injector, and a peripheral portion connecting the inward protruding portion and the center portion. The fuel injector and the cavity are configured so that fuel injected from fuel injector directs to the proximity of the border between the inward protruding portion and the peripheral portion. The peripheral portion consists of a first portion located farthermost from the fuel injector, a second portion located between the inward protruding portion and the first portion, and a third portion located between the first portion and the center portion. The radii of arcs of the peripheral portion decrease from the second portion to the first portion and increase from the first portion to the third portion.

Abstract: A fuel injection nozzle for a diesel engine. The fuel injection nozzle may include a plurality of injection hole groups, each having two injection holes respectively. A distance between the two injection holes, an angle between longitudinal axes of the two injection holes and an angle between horizontal axes of said two injection holes of each injection hole group are each set such that fuel sprays injected from said two injection holes will form a single fuel spray cloud after the fuel sprays collide with a side wall of a combustion chamber formed in a top surface of a piston of the engine, and such that the distance between collision points of the fuel sprays will be in a predetermined range in which a penetration force of said fuel spray cloud along a longitudinal direction of said combustion chamber received after collision with said wall of said combustion chamber is at or near a predetermined maximum value.

Abstract: An exemplary method of controlling an internal combustion engine system is described herein. The internal combustion engine system includes an internal combustion engine, a valve driving mechanism which reciprocally drives an intake valve and an exhaust valve for a combustion chamber of the internal combustion engine, a turbocharger including a turbine and a compressor, and a first EGR passage which communicates an exhaust passage downstream of the emission control device and an intake passage upstream of the compressor. The exemplary method includes shutting off supplying fuel to the combustion chamber under a predetermined condition, and decreasing a lift of the intake or exhaust valve for the combustion chamber during the shutting off supplying fuel to the combustion chamber compared to in a case of supplying fuel to said combustion chamber.

Abstract: A wall shape of a cavity consists of an inward protruding portion located at the periphery of an opening, a center portion projecting toward a fuel injector, and a peripheral portion connecting the inward protruding portion and the center portion. The fuel injector and the cavity are configured so that fuel injected from fuel injector directs to the proximity of the border between the inward protruding portion and the peripheral portion. The peripheral portion consists of a first portion located farthermost from the fuel injector, a second portion located between the inward protruding portion and the first portion, and a third portion located between the first portion and the center portion. The radii of arcs of the peripheral portion decrease from the second portion to the first portion and increase from the first portion to the third portion.

Abstract: A fuel injection nozzle for a diesel engine. The fuel injection nozzle may include a plurality of injection hole groups, each having two injection holes respectively. A distance between the two injection holes, an angle between longitudinal axes of the two injection holes and an angle between horizontal axes of said two injection holes of each injection hole group are each set such that fuel sprays injected from said two injection holes will form a single fuel spray cloud after the fuel sprays collide with a side wall of a combustion chamber formed in a top surface of a piston of the engine, and such that the distance between collision points of the fuel sprays will be in a predetermined range in which a penetration force of said fuel spray cloud along a longitudinal direction of said combustion chamber received after collision with said wall of said combustion chamber is at or near a predetermined maximum value.

Abstract: An engine exhaust gas purifier includes: an injection controller allowing a fuel injection valve to inject fuel near the top dead center on each compression stroke; an EGR amount controller for controlling the amount of exhaust gas recirculated into a combustion chamber; an excess air ratio controller for controlling the excess air ratio so that the local equivalence ratio in a late combustion stage is lower than the equivalence ratio at which soot is produced; and an intake air temperature controller for controlling the temperature of intake air after being mixed with exhaust gas. The intake air temperature controller controls the temperature of intake air within a temperature range lower than an upper temperature limit below which a predetermined ignition delay time can be secured and higher than a lower temperature limit above which the production of HC and CO can be avoided.

Abstract: An engine exhaust gas purifier includes: an injection controller allowing a fuel injection valve to inject fuel near the top dead center on each compression stroke; an EGR amount controller for controlling the amount of exhaust gas recirculated into a combustion chamber; an excess air ratio controller for controlling the excess air ratio so that the local equivalence ratio in a late combustion stage is lower than the equivalence ratio at which soot is produced; and an intake air temperature controller for controlling the temperature of intake air after being mixed with exhaust gas. The intake air temperature controller controls the temperature of intake air within a temperature range lower than an upper temperature limit below which a predetermined ignition delay time can be secured and higher than a lower temperature limit above which the production of HC and CO can be avoided.

Abstract: To suppress deposition of fuel injected at an early timing on a wall surface for preventing the degradation in fuel efficiency and increase in the amount of harmful components in an exhaust gas, in a direct-injection diesel engine which controls the injector to cause a combustion configuration dominated by the compressive ignition of the premixture while the engine is in the premixed combustion region defined on a low load side. When fuel is injected at an early timing to form the premixture, at least one of the pulse width to be inputted into the injector and the fuel pressure is or are adjusted according to the change in the injection timing, and corrected according to the intake air temperature or the intake pressure. If an allowable pulse width is insufficient to inject fuel in the amount corresponding to a target torque, fuel is injected in a divided manner.

Abstract: To optimize an ignition timing of premixture for improving fuel efficiency regardless of significant change in an EGR ratio or a fluctuation in temperature of recirculated exhaust gas and temperature in a combustion chamber, there is provided a control apparatus for a diesel engine which controls an injector extending into the combustion chamber to execute a main-injection for injecting fuel and increasing the EGR ratio, so as to attain the premixed compressive ignition combustion while the engine is in the premixed combustion region on the low load side. Just before or after a cool flame reaction occurs in the mixture formed by the main-injection, an auxiliary-injection is executed so that the latent heat of vaporization of the fuel decreases the temperature of the mixture to delay the ignition to a timing near TDC. The auxiliary-injection amount is adjusted according to the estimated value of EGR ratio or the change in the crank angular velocity to optimize the ignition timing of the mixture.