Nissan Motor Company Limited

Takashi Shirakawa

Manabu Miura

Yasuhisa Kitahara

Hiroyuki Itoyama

Yasutaka Ishibashi

Hikari Todoroki

Kousuke Yasuhara

Makoto Sakai

Shuji Kimura

Hiromichi Miwa

Hitoshi Onodera

Kensuke Osamura

Hiroyuki Aizawa

A diesel particulate filter () which traps particulate matter and a NOx trap catalyst () which traps nitrogen oxides are installed in series in an exhaust passage () of a diesel engine (). A controller () calculates a particulate matter deposition amount in the diesel particulate filter () (S). The controller (), when the particulate matter deposition amount exceeds a first predetermined amount (PM), prevents sharp increase of the particulate matter deposition amount by prohibiting rich spike where the oxygen concentration of the exhaust gas is controlled to a value corresponding to a rich air-fuel ratio in order to regenerate the NOx trap catalyst () (S, S, S), and prevents the particulate matter deposition amount of the diesel particulate filter () from reaching a limit.

Exhaust gas purification control of diesel engine

In an engine having apparatus for a post-exhaust process, surging is prevented when the air excess coefficient is changed to a lean condition from a rich condition in order to carry out the post-exhaust process. The present engine control apparatus comprises a turbo-supercharger driven by exhaust energy of an engine in a vehicle, an EGR path interconnecting an exhaust path and an inlet path of the engine, at least one of a NOtrap catalyzer and a diesel particulate filter (DPF) mounted in the exhaust path for purifying exhaust discharged from the engine, an EGR valve for adjusting the flow rate of air passing through the EGR path, an air excess coefficient control unit for controlling the air excess coefficient, depending on driving conditions, and wherein the EGR valve is operable to close when the air coefficient control unit controls the air excess coefficient so as to be in a lean condition.

Engine control apparatus

In exhaust gas purifying apparatus and method for an internal combustion engine, an abnormality determination of an NOx (Nitrogen Oxides) removing catalyst is executed on the basis of output values of both of a first exhaust gas atmosphere detecting section and a second exhaust gas atmosphere detecting section (for example, oxygen concentration sensors interposed in an exhaust passage of the engine between inlet and outlet portions of the NOx removing catalyst) from a time at which an output value of the first exhaust gas atmosphere detecting section is varied to a first predetermined value to a time at which the output value of the second exhaust gas atmosphere detecting section is reached to a second predetermined value when an exhaust gas atmosphere varying section (control unit) increases the ratio of a reducing agent in the exhaust gas.

Exhaust gas purifying apparatus and method for internal combustion engine

In order to prevent the generation of surge noise or other abnormal phenomena during deceleration of a vehicle, the present engine control apparatus comprises a turbo-supercharger driven by exhaust energy of the engine, at least one of an NOtrap catalyzer and a DPF mounted in the exhaust path of the engine for purifying the exhaust, an EGR path interconnecting the exhaust path and the inlet path of the engine, an EGR valve for adjusting the cross-section of the duct of the EGR path, means for detecting deceleration, and a fuel cutoff control means that, if predetermined conditions are satisfied, effects fuel cutoff control to reduces the rate of fuel injection, wherein the EGR valve is closed during the period of vehicle deceleration.

In exhaust gas purifying apparatus and method for an internal combustion engine, a degree of a performance deterioration of an NOx trap catalyst is determined on the basis of a detected air-fuel ratio variation time difference, at the performance deterioration determination of the NOx trap catalyst, the degree of the performance deterioration with at least one of correcting factors of a quantity of NOx trapped by means of the NOx trap catalyst, a reducing agent supply quantity by which a reducing agent is supplied to the NOx trap catalyst, and catalyst temperature which is a temperature of the NOx trap catalyst, and at least one of the correcting factors is reflected on the determination of the degree of the performance deterioration of the NOx trap catalyst.

An exhaust gas cleaning system is provided that comprises a particulate filter and an NOx trapping catalytic converter disposed upstream of the particulate filter. The exhaust gas cleaning system is configured to determine a combustion amount of the particulate matter accumulated in the particulate filter that are combusted by the NOx in the exhaust gas, and adjust the combustion amount of the particulate matter based on an NOx adsorption condition of the NOx trapping catalytic converter. Then, the exhaust gas cleaning system is configured to estimate a particulate matter accumulation amount in the particulate filter by subtracting the adjusted combustion amount of the particulate matter from a discharge amount of the particulate matter. Thus, the amount of particulate matter accumulated in the particulate filter is estimated more accurately by taking into consideration the combustion of particulate matter by NOx in the exhaust gas.

Exhaust gas cleaning system

A diagnosis system of an exhaust aftertreatment apparatus for an internal combustion engine is arranged to execute a first deterioration diagnosis of the exhaust aftertreatment apparatus on the basis of a change of a catalyst downstream side air/fuel ratio relative to a change of a catalyst upstream side air/fuel ratio during a rich spike control and to execute a second deterioration diagnosis from an inversion cycle of a feedback quantity during the feedback control of the catalyst downstream side air/fuel ratio during a stoichiometric control when the first deterioration diagnosis made a deterioration determination.

Diagnosis system of exhaust aftertreatment apparatus for internal combustion engine

A fuel injection control device is configured to suppress the effect of pressure pulsation occurring inside the accumulator section of an engine due to a first fuel injection and thereby accurately control the fuel injection quantity in an engine configured to execute a plurality of fuel injections per cycle. When the fuel injection quantity for a second injection executed after a first injection is set, the fuel injection interval is detected and the fuel injection quantity is revised based on the fuel injection interval. The amount of time from the end of the first injection (e.g., a pilot injection) to the start of the second injection (e.g., a main injection) is used as the fuel injection interval.

Engine fuel injection control device

An engine control device is configured to prevent surging in an engine equipped with both a variable-nozzle turbocharger and an EGR device while curbing costs by utilizing existing equipment and avoiding undesirable secondary effects. When the engine is in a prescribed engine operating state in which the fuel injection quantity should be reduced, the EGR quantity delivered by the EGR device is reduced to a value lower than the normal value and the opening degree of the turbine nozzle of the turbocharger is increased. The prescribed engine operating state is defined to exist when the vehicle is decelerating and when the fuel injection quantity is decreased after regeneration of the NOx trapping catalytic converter.

Engine control device

An exhaust gas purifying system for an internal combustion engine is arranged to determine a recovery execution timing for recovery processing of recovering an exhaust gas purifying device such as a particulate filter and a NOx trap catalyst from a specific content stacked state, to determine a target air/fuel ratio for executing the recovery processing, to determine a first engine controlled variable relating to an air/fuel ratio on the basis of the target air/fuel ratio, and to determine a second engine controlled variable relating to a combustion period at a value different from a value employed during normal processing when the recovery processing is executed.

Exhaust gas purifying system for internal combustion engine

A turbocharged engine control system is provided that comprises an exhaust gas after-treatment system and a variable-capacity turbocharger. The turbocharged engine control system is configured to estimate a clogging ratio of the exhaust gas after-treatment system based on an equivalent surface area of the exhaust gas after-treatment system. A correction value is determined based on a turbine outlet pressure and the correction value is added to the clogging ratio. A target nozzle opening value is corrected such that the nozzle opening value increases as the exhaust gas after-treatment system becomes more clogged. Consequently, as the exhaust gas after-treatment system becomes clogged, the increase in pressure on the inlet side of the exhaust turbine (which acts as back pressure with respect to the engine) is suppressed and the increase in the internal EGR ratio caused by residual gas is also suppressed.

Turbocharged engine control system

An exhaust purifying device is arranged in an exhaust gas passage extending from an internal combustion engine. The exhaust purifying device includes a NOx trapping catalyst that traps NOx in the exhaust gas when an exhaust air/fuel ratio is leaner than stoichiometric and releases the trapped NOx therefrom when the exhaust air/fuel ratio is richer than stoichiometric, and a particulate filter that collects a particulate matter in the exhaust gas. A condition detecting device is arranged to detect a condition of the particulate filter. An exhaust air/fuel ratio control device is arranged to control the exhaust gas from the engine in such a manner that the exhaust gas has a target exhaust air/fuel ratio. When the exhaust air/fuel ratio is changed from a stoichiometric or richer side to a leaner side, the exhaust air/fuel ratio control device varies the exhaust air/fuel ratio under the leaner air/fuel exhaust condition in accordance with the condition of the particulate filter.

Exhaust emission control system of internal combustion engine

An engine fuel injection control system including a particulate filter is configured to compare an accelerator request fuel injection quantity based on an accelerator depression amount to an air fuel ratio request fuel injection quantity determined based on a target air fuel ratio based on the engine operating condition. The engine fuel injection control system is configured to select the smaller of the accelerator request fuel injection quantity and the air fuel ratio request fuel injection quantity as a target fuel injection quantity. When the engine is operating in a low rotational speed region with full load, the target air fuel ratio is adjusted to a value substantially equal to the air fuel ratio that provides a maximum torque. Thus, the fuel is injected to achieve an air fuel ratio close to the stoichiometric air fuel ratio the torque performance and acceleration performance can be improved.

Engine fuel injection control system

A diesel engine () provided with a NOx catalyst (A) and a diesel particulate filter (B) performs lean burn operation during normal running, rich burn operation during regeneration of the NOx catalyst (A), operation under the stoichiometric air-fuel ratio during desulphating of the NOx catalyst (A), and operation under a slightly lean air-fuel ratio to regenerate the filter after desulphating of the NOx catalyst (A). When the lean burn operation is applied, a controller () first controls the fuel injection amount, and controls an air supply amount based on the fuel injection amount. When rich burn operation is applied, the controller () first controls the air supply amount and controls the fuel injection amount based on the air supply amount. Due to this control, the response of the excess air factor control is enhanced while preventing torque fluctuation accompanying the variation of the target excess air factor.

Excess air factor control of diesel engine

A diesel particulate filterthat traps particulate matters in an exhaust gas and a NOx trap catalystthat traps NOx in the exhaust gas are disposed in an exhaust passage () in an internal combustion engine (). When a regeneration timing of the diesel particulate filter () and one of a regeneration timing of SOx and a regeneration timing of NOx are overlapped, the diesel particulate filter regeneration is carried out first and thereafter, the SOx regeneration or the NOx regeneration is carried out.

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Yokohama, Japan

Takashi Shirakawa