Abstract: A control apparatus for a diesel engine includes a neighboring temperature estimating section which estimates a temperature of a neighborhood of a glow plug that heats an interior of a cylinder upon startup, and a supercharging pressure control section which controls a supercharging pressure in such a way that a rotation fluctuation of the engine does not increase, on the basis of the estimated temperature of the neighborhood of the glow plug.

Abstract: A direct injection diesel engine is provided with a fuel injection nozzle which is capable of performing a multistage injection. In a middle-or-high load region, in order to reduce soot, an after-injection is performed immediately after a main injection. An injection timing of the after-injection is set from a map in accordance with a driving condition. During a transient time, the injection timing of the after-injection is corrected on a basis of a difference ?P between an actual rail pressure rPrail and a target rail pressure tPrail. In a case where the injection timing after the correcting is more retardation angle side than a threshold value, the after-injection is inhibited.

Abstract: A control device for diesel engine controls a diesel engine with a turbo charger that coaxially joins an intake compressor and an exhaust turbine, and drives the intake compressor with energy of exhaust gas which flows into the exhaust turbine to pressurize intake air, and a fresh air/secondary air supply device that supplies fresh air or secondary air to an exhaust passage upstream of the exhaust turbine. The control device for diesel engine includes a gas flow stagnation region determination means that determines whether engine operation conditions or a state of the turbo charger are/is in a gas flow stagnation region, and a fresh air/secondary air supply means that supplies fresh air or secondary air to the exhaust passage upstream of the exhaust turbine by the fresh air/secondary air supply device when the engine operation conditions or the state of the turbo charger are/is in a gas flow stagnation region.

Abstract: A direct injection diesel engine includes a piston having a reentrant cavity and a multi-hole fuel injection nozzle disposed on a center line of the cavity. The cavity is formed by a lip portion defining a smallest diameter at a position below a piston crown surface and a raised portion formed at a center of the bottom and shaped like a frustum of a cone. A conical surface of the raised portion is formed to have an angle pointing to a spray point of the fuel injection nozzle at a piston top dead center position. The height position of a top surface is substantially equal to the height position of the lip portion. This structure is to promote the oxidation of soot by utilizing the air in the central part of the cavity.

Abstract: A control apparatus for a diesel engine includes a neighboring temperature estimating section which estimates a temperature of a neighborhood of a glow plug that heats an interior of a cylinder upon startup, and a supercharging pressure control section which controls a supercharging pressure in such a way that a rotation fluctuation of the engine does not increase, on the basis of the estimated temperature of the neighborhood of the glow plug.

Abstract: A control apparatus for a diesel engine includes a neighboring temperature estimating section which estimates a temperature of a neighborhood of a glow plug that heats an interior of a cylinder upon startup, and a supercharging pressure control section which controls a supercharging pressure in such a way that a rotation fluctuation of the engine does not increase, on the basis of the estimated temperature of the neighborhood of the glow plug.

Abstract: A fuel injection nozzle disposed in a center of a reentrant cavity combustion chamber has first and second nozzle hole groups whose inclination angles with respect to a cylinder center axis line are different. A nozzle hole diameter of the second nozzle hole group is larger than that of the first one. First and second nozzle holes are alternately arranged in a circumferential direction. A glow plug projects, in a height direction of the cylinder, up to a height of a spray center axis line (F2) of the second nozzle hole directed at a lower side. Therefore the glow plug can contact fuel masses formed by sprays from both the first and second nozzle holes. The glow plug is positioned between spray center axis lines (F1, F2) in the circumferential direction, and positioned at a swirl downstream side of spray center axis line (F2).

Abstract: A direct injection diesel engine is provided with a fuel injection nozzle which is capable of performing a multistage injection. In a middle-or-high load region, in order to decrease soot, an after-injection is performed immediately after a main injection. In a case of fuel with a low Cetane number, the after-injection can cause a worsening of soot. Hence, an ignition delay interval (period of time) of the main injection is determined. In a case where the ignition time delay interval (period of time) is equal to or above a threshold value, the after-injection is inhibited.

Abstract: A piston of a direct injection type diesel engine has a re-entrant type cavity, and a fuel injection nozzle with multiple nozzle holes is arranged on the center line thereof. The cavity has a lip portion, which is the portion thereof having the smallest diameter, positioned below a piston crown surface and a pocket portion formed above the lip portion. The pocket portion is positioned at a height to which a pilot injection injected prior to the top dead center under engine idling is directed, and the position of a wall surface is so set that a leading part of the injection spray does not collide strongly therewith. The fuel from the pilot injection temporarily stays in the pocket portion and moves into the cavity by means of a subsequent squish flow. Accordingly, an increase in unburned hydrocarbons is suppressed.

Abstract: A direct injection diesel engine includes a piston having a reentrant cavity and a multi-hole fuel injection nozzle disposed on a center line of the cavity. The cavity is formed by a lip portion defining a smallest diameter at a position below a piston crown surface and a raised portion formed at a center of the bottom and shaped like a frustum of a cone. A conical surface of the raised portion is formed to have an angle pointing to a spray point of the fuel injection nozzle at a piston top dead center position. The height position of a top surface is substantially equal to the height position of the lip portion. This structure is to promote the oxidation of soot by utilizing the air in the central part of the cavity.

Abstract: A direct injection diesel engine is provided with a fuel injection nozzle which is capable of performing a multistage injection. In a middle-or-high load region, in order to decrease soot, an after-injection is performed immediately after a main injection. In a case of fuel with a low Cetane number, the after-injection can cause a worsening of soot. Hence, an ignition delay interval (period of time) of the main injection is determined. In a case where the ignition time delay interval (period of time) is equal to or above a threshold value, the after-injection is inhibited.

Abstract: A direct injection diesel engine is provided with a fuel injection nozzle which is capable of performing a multistage injection. In a middle-or-high load region, in order to reduce soot, an after-injection is performed immediately after a main injection. An injection timing of the after-injection is set from a map in accordance with a driving condition. During a transient time, the injection timing of the after-injection is corrected on a basis of a difference ?P between an actual rail pressure rPrail and a target rail pressure tPrail. In a case where the injection timing after the correcting is more retardation angle side than a threshold value, the after-injection is inhibited.

Abstract: A control device for diesel engine controls a diesel engine with a turbo charger that coaxially joins an intake compressor and an exhaust turbine, and drives the intake compressor with energy of exhaust gas which flows into the exhaust turbine to pressurize intake air, and a fresh air/secondary air supply device that supplies fresh air or secondary air to an exhaust passage upstream of the exhaust turbine. The control device for diesel engine includes a gas flow stagnation region determination means that determines whether engine operation conditions or a state of the turbo charger are/is in a gas flow stagnation region, and a fresh air/secondary air supply means that supplies fresh air or secondary air to the exhaust passage upstream of the exhaust turbine by the fresh air/secondary air supply device when the engine operation conditions or the state of the turbo charger are/is in a gas flow stagnation region.

Abstract: Fuel injection nozzle (6) disposed in a center of reentrant cavity combustion chamber (5) has first and second nozzle hole groups whose inclination angles with respect to cylinder center axis line are different, one is large inclination angle and the other is small inclination angle. Nozzle hole diameter of second nozzle hole group is larger than that of the first one. First and second nozzle holes are alternately arranged in a circumferential direction. Glow plug (11) projects, in a height direction of cylinder (4), up to a height of spray center axis line (F2) of the second nozzle hole directed at a lower side, therefore glow plug (11) can contact fuel masses formed by sprays from both first and second nozzle holes. Glow plug (11) is positioned between spray center axis lines (F1, F2) in the circumferential direction, and positioned at swirl downstream side of spray center axis line (F2).

Abstract: A control apparatus for a diesel engine includes a neighboring temperature estimating section which estimates a temperature of a neighborhood of a glow plug that heats an interior of a cylinder upon startup, and a supercharging pressure control section which controls a supercharging pressure in such a way that a rotation fluctuation of the engine does not increase, on the basis of the estimated temperature of the neighborhood of the glow plug.