Mitsubishi Fuso Truck & Bus Corporation

Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Mitsubishi Jukogyo Kabushiki Kaisha

Shinji Nakayama

Keiki Tanabe

Susumu Kohketsu

Susumu Kouketsu

Akira Suzuki

Hiroshi Oikawa

Hiroshi Nakagawa

Yasuaki Kumagai

Yoichiro Kono

Daisuke Sunohara

Koji Mori

Kiyoshi Miyajima

Masayoshi Nakashima

Takazou Hakozaki

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.

Apparatus and method for estimating NOx trap catalyst adsorption amount

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.

Common rail fuel injection system

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.

Fuel injection system

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.

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.

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.

Pressure-elevating type fuel injecting system

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.

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.

Fuel injection apparatus of engine

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.

Accumulator type fuel injection apparatus

In a common rail system comprised of a first accumulator storing high-pressure fuel and a second accumulator storing low-pressure fuel, additional fuel is injected when a fuel pressure in a fuel passage or in the second accumulator (low inlet pressure of an injector) is reduced to a low pressure approximate to the pressure of the low-pressure fuel stored in the second accumulator after a switching valve is operated for disconnection from the fuel passage (switching valve drive signal OFF) at a point in time when a main injection control device finishes the injection of fuel (injector drive signal OFF) or after the main injection control device finishes the injection of fuel. This keeps the fuel pressure as low as possible during post injection to prevent the fuel from adhering to the wall surfaces of cylinder liners.

Accumulator fuel injection system

A water injection amount control system for a fuel and water injection engine, comprises running state detecting unit for detecting the running state of the engine; an EGR system for recirculating part of exhaust gas of the engine to a combustion chamber of the engine; EGR system operating state detecting unit for detecting or estimating the operating state of the EGR system; water injection amount regulating unit for regulating an amount of water to be injected to the combustion chamber of the engine; and control unit for controlling the operation of the water injection amount regulating unit: wherein the system is arranged to have water injection amount setting unit for deciding a water injection amount based on information from the running state detecting unit and on the operating state of the EGR system detected by the EGR system operating state detecting unit, so that the control unit controls the operation of the water injection amount regulating unit based on the water injection amount decided by the water injection amount setting unit.

Water injection amount control system for fuel and water injection engine

An exhaust gas purifier for a diesel engine is positioned in the middle of an inlet system for supplying air to a combustion chamber. The exhaust gas purifier includes an HC (hydrocarbon) supply source, and a zeolite catalyst converter, which is activated by the hydrocarbon as a reduction agent to crack NOx (oxides of nitrogen) in the exhaust gas, for thereby purifying the exhaust gas.

Growing community of inventors

Tokyo, Japan

Shinji Nakayama