Abstract: In a common rail internal combustion engine having a pressure increase mechanism, when the pressure increase mechanism is activated, fuel is injected according to a target injection quantity determined by adding an increase in injection quantity calculated depending on a load on a supply pump to a demanded injection quantity.

Abstract: A combustion control system of a diesel engine, which controls a fuel-injection timing by switching from one to another of a normal combustion mode, a premix combustion mode, and a transition mode of between these modes, and switches from the normal combustion mode to the transition mode if an intake oxygen density is equal to or lower than a predetermined value in the normal combustion mode.

Abstract: There is provided an apparatus that estimates the NOx adsorption amount, comprising a NOx trap catalyst that is disposed in an exhaust passage of an engine, for adsorbing NOx in exhaust gases during lean operation and releasing and reducing the adsorbed NOx during rich operation, an operation unit that computes an amount of emission from the catalyst during rich operation by using a map or a polynomial equation that reflects emissions from the catalyst based on the exhaust gas temperature and the exhaust gas flow rate of the exhaust passage and the excess-air factor upstream of the catalyst, and an estimating unit that estimates an amount of adsorption in the NOx trap catalyst from the computed emission amount.

Abstract: Immediately before fuel pressure is increased by a pressure-increase mechanism, a pressure-increase control valve of each cylinder is opened in timing that does not overlap the timing of opening of an injection control valve, and the period of time for which the pressure-increase control valves is opened is gradually increased. As a result, it is possible to prevent the quantity of fuel consumed by the pressure-increase mechanism from rapidly increasing when the increase of fuel pressure is started.

Abstract: A booster unit is provided in an injector of a fuel injection system. The booster unit comprises a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A controller has an indication-value setting step of setting an indication value of a target pressure in a common rail in correspondence to an engine operation state, a determination step of determining whether or not the indication value of the pressure in the common rail is in a direction of reduction to be lower in comparison to a previously set indication value, and a step of prolonging an open time of a discharge valve of the booster unit when the determination step has determined that the indication value is in the direction of reduction.

Abstract: Immediately before fuel pressure is increased by a pressure-increase mechanism, a pressure-increase control valve of each cylinder is opened in timing that does not overlap the timing of opening of an injection control valve, and the period of time for which the pressure-increase control valves is opened is gradually increased. As a result, it is possible to prevent the quantity of fuel consumed by the pressure-increase mechanism from rapidly increasing when the increase of fuel pressure is started.

Abstract: A booster unit is provided in an injector of a fuel injection system. The booster unit comprises a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A controller has an indication-value setting step of setting an indication value of a target pressure in a common rail in correspondence to an engine operation state, a determination step of determining whether or not the indication value of the pressure in the common rail is in a direction of reduction to be lower in comparison to a previously set indication value, and a step of prolonging an open time of a discharge valve of the booster unit when the determination step has determined that the indication value is in the direction of reduction.

Abstract: An exhaust emission control device of an internal combustion engine includes a fuel supply unit provided in a fuel supply passage, for supplying a reducing agent directly to a NOx trap catalytic converter; an addition pressure detection unit for detecting the supply pressure of the reducing agent supplied by the fuel supply unit; and a controller for calculating the amount of NOx adsorbed by the catalytic converter. When the supply pressure of the reducing agent is almost zero, the controller prohibits calculation of NOx adsorption amount depending on the supply of the reducing agent, creates a rich state in a cylinder, carries out calculation of NOx adsorption amount depending on the created rich state, and causes release and reduction of the adsorbed NOx.

Abstract: A booster unit is provided in an injector of a fuel injection system. The booster unit includes a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A needle valve drive unit includes a pressure-receiving piston and an open/close valve. A return passage is connected to a discharge side of the open/close valve. A fuel discharge passage in communication with the discharge valve is combined with the return passage in a confluence portion. A check valve is provided between the confluence portion and the open/close valve. A check valve permits the fuel discharged to the return passage from a pressurization chamber to be directed to the confluence portion, and prevents the fuel discharged to the fuel discharge passage from the backpressure chamber from being directed the open/close valve.

Abstract: There is provided an apparatus that estimates the NOx adsorption amount, comprising a NOx trap catalyst that is disposed in an exhaust passage of an engine, for adsorbing NOx in exhaust gases during lean operation and releasing and reducing the adsorbed NOx during rich operation, an operation unit that computes an amount of emission from the catalyst during rich operation by using a map or a polynomial equation that reflects emissions from the catalyst based on the exhaust gas temperature and the exhaust gas flow rate of the exhaust passage and the excess-air factor upstream of the catalyst, and an estimating unit that estimates an amount of adsorption in the NOx trap catalyst from the computed emission amount.

Abstract: A booster unit is provided in an injector of a fuel injection system. The booster unit includes a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A controller includes an indication-value setting step which sets an indication value of a target pressure in a common rail in correspondence to an engine operation state, a determination step which determines whether or not the indication value of the pressure in the common rail is in a direction of reduction to be lower in comparison to a previously set indication value, and a booster piston pseudo-operation step which opens the discharge valve at timing other than injection operation of the injector when the determination step has determined that the indication value is in the direction of reduction.

Abstract: A booster unit is provided in an injector of a fuel injection system. The booster unit includes a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A controller includes an indication-value setting step which sets an indication value of a target pressure in a common rail in correspondence to an engine operation state, a determination step which determines whether or not the indication value of the pressure in the common rail is in a direction of reduction to be lower in comparison to a previously set indication value, and a booster piston pseudo-operation step which opens the discharge valve at timing other than injection operation of the injector when the determination step has determined that the indication value is in the direction of reduction.

Abstract: A booster unit is provided in an injector of a fuel injection system. The booster unit includes a booster piston accommodated in a pressure chamber, and a discharge valve capable of discharging fuel in a backpressure chamber. A needle valve drive unit includes a pressure-receiving piston and an open/close valve. A return passage is connected to a discharge side of the open/close valve. A fuel discharge passage in communication with the discharge valve is combined with the return passage in a confluence portion. A check valve is provided between the confluence portion and the open/close valve. A check valve permits the fuel discharged to the return passage from a pressurization chamber to be directed to the confluence portion, and prevents the fuel discharged to the fuel discharge passage from the backpressure chamber from being directed the open/close valve.

Abstract: A pressure-elevating type fuel injecting system selectively injects via injectors fuel stored in a common rail or fuel whose pressure is elevated by a pressure elevating mechanism into a combustion chamber, and comprises a crank angle sensor producing crank pulse signals in accordance with operating states of an engine, a pulse interval calculating unit calculating pulse intervals between respective crank pulse signals, and a determination unit determining the malfunction of the pressure elevating mechanism when a variation of the pulse interval is above a determination threshold.

Abstract: The present invention is a method for estimating a NOx occlusion amount of a NOx occlusion catalyst interposed in an exhaust passage in an engine, which is constituted such that a NOx occlusion amount is estimated by using a polynomial reflected with NOx occlusion characteristics of a NOx occlusion catalyst and each coefficient of the polynomial is sequentially corrected on the basis of NOx purification rates actually measured.

Abstract: An accumulator type fuel injection system adapted to prevent engine trouble by making a judgement that fuel injection rate switching change-over valves provided correspondingly to fuel injection nozzles in cylinders, a valve for controlling the pressure in a low-pressure accumulator or means for detecting fuel pressures in accumulators gets out of order, and carrying out when any of these parts break down a control operation of a limp-home mode in which a region of an operation of an engine is limited. To provide such an accumulator type fuel injection system, a control means 8 is formed so that, when a judgement that first control valves 5, a second control valve 34 or pressure sensors 3a, 4a for detecting the fuel pressures in the respective accumulators get out of order is given, the control means 8 sets a discharge pressure of a fuel pump 1 not higher than a permissible pressure in a second accumulator 4, and injects a fuel from fuel injection nozzles 9.

Abstract: A pressure-elevating type fuel injecting system pressurizes high pressure fuel from a pressure accumulating chamber using a pressure-elevating mechanism and injects the pressure-elevated fuel into combustion chambers by injectors. The pressure-elevating type fuel injecting system comprises a target fuel injection quantity setting unit which sets a target fuel injection quantity, a time difference setting unit which sets a time difference between a timing for opening an injector electromagnetic valve and a timing for operating an pressure-elevating mechanism electromagnetic valve, an initial fuel injection quantity calculating unit calculating an initial fuel injection quantity on the basis of a time-dependent variation of fuel pressure and the time difference, and a final injection period setting unit which calculates an operation period of the injector electromagnetic valve, on the basis of a final fuel injection quantity and the time-dependent variation of the pressure of the pressure-elevated fuel.

Abstract: A pressure-elevating type fuel injecting system selectively injects via injectors fuel stored in a common rail or fuel whose pressure is elevated by a pressure elevating mechanism into a combustion chamber, and comprises a crank angle sensor producing crank pulse signals in accordance with operating states of an engine, a pulse interval calculating unit calculating pulse intervals between respective crank pulse signals, and a determination unit determining the malfunction of the pressure elevating mechanism when a variation of the pulse interval is above a determination threshold.

Abstract: By setting a switching timing of switching means that connects either one of a high pressure fuel source and a low pressure fuel source to an injector earlier than a point of time when an injector finishes a high pressure fuel injection, leak fuel or return fuel is reduced and an engine load is reduced and therefore mileage is improved.

Abstract: A common-rail injection system includes a first accumulator of high pressure and a second accumulator of low pressure. The common-rail injection system includes a post injection control device for injecting additional low-pressure fuel from the second accumulator through a fuel injection nozzle after main fuel is injected. The post injection control device injects the additional fuel the injection terminates at a first timing when the fuel pressure in either fuel passage or second accumulator lowers to a predetermined value lower than that of the high-pressure fuel or at a second timing when an exhaust stroke of the engine is completed, whichever earlier.