Abstract: To determine whether an exhaust gas purification catalyst (42) of an engine (1) has deteriorated, first deterioration of the catalyst (42) is determined on the basis of an excess air ratio difference, which is a value expressing a difference in the oxygen concentration on the upstream side and downstream side of the catalyst (42). When the catalyst (42) is determined to have deteriorated on the basis of the excess air ratio difference, the air-fuel ratio of the engine (1) is feedback-controlled to a stoichiometric air-fuel ratio, and deterioration of the catalyst (42) is determined again on the basis of a value expressing a difference in the air-fuel ratio variation on the upstream side and downstream side of the catalyst (42) at that time.

Abstract: A method of controlling an internal combustion engine for warm-up of catalyst of an exhaust gas treatment device is disclosed. The method comprises generating a warm-up demand for heating the catalyst subject to constraint on stable combustion. Based on the warm-up demand, a reduction in excess air ratio is determined. A desired value in excess air ratio is modified by the reduction to provide a modified desired value in excess air ratio. Based on the reduction, a desired value in EGR rate is modified to provide a modified desired value in EGR rate. Based on the modified desired value in EGR rate, an EGR command signal is determined.

Abstract: An engine fuel injection control system is configured to alleviate the torque fluctuation that occurs due to deviation in a pilot injection timing when the excess air ratio is changed suddenly from lean to rich. When the excess air ratio changes by a large amount, the pilot injection interval is changed in accordance with the actual excess air ratio by executing an interpolation calculation based on the target excess air ratio and the actual excess air ratio. During the transient period when the actual excess air ratio is converging toward the target excess air ratio, the pilot injection interval is changed in accordance with the change in the actual excess air ratio. As a result, it is possible to alleviate torque fluctuation by suppressing the tendency of the pilot injection interval to change rapidly in a step-like manner between target values before and after the excess air ratio changes.

Abstract: When an air excess rate is controlled to be reduced based upon an early activation demand of an exhaust gas purification apparatus or a regeneration demand of NOx trap catalyst at a state immediately after an engine has started from at a cold condition, a fuel injection state (injection timing of a main injection, a pilot injection quantity, an injection pressure and so on) from a fuel injection valve is variably controlled so that a crank angle position where a heat generation rate is maximized is kept constant, thereby stabilizing a combustion and preventing combustion fluctuations.

Abstract: A combustion control apparatus for an internal combustion engine having an exhaust gas purifier in an exhaust passage, includes a controller that controls supply of fuel and air to the engine. The controller is configured to produce preliminary combustion at or near compression top dead center and main combustion after an end of the preliminary combustion under a predetermined condition based on a condition of the exhaust gas purifier. The controller is further configured to determine a target intake air quantity by adding an increase correction to the target intake air quantity based on a torque correction value and determine a target fuel injection quantity by calculating the target fuel injection quantity from an actual air quantity and a target air/fuel ratio. A combustion control method is also provided.

Abstract: An engine exhaust gas cleaning apparatus is provided to suppress EGR ratio fluctuations when the excess air ratio is adjusted and thereby stabilize the engine operating performance.

Abstract: An engine exhaust gas cleaning apparatus is provided to minimize torque shock as during regeneration of an exhaust gas cleaning device. The engine exhaust gas cleaning apparatus comprises a fuel delivery device that delivers fuel to an engine at a lean excess air ratio during normal operation of the engine; a NOx trapping catalytic converter that adsorbs NOx from the exhaust gas during the lean operation; a regeneration control section that adjusts the excess air ratio to a rich target value to regenerate the NOx trapping catalytic converter; a feedback control section that feedback-controls the fuel delivery quantity to hold the excess air ratio at the target value during regeneration; a feedback control restricting section that restricts the feedback control during regeneration until the difference between the target value and the actual excess air ratio is less than a prescribed value.

Abstract: An exhaust gas cleaning apparatus for an engine has a NOx trapping catalytic converter and a control unit for controlling an intake air throttle valve and a fuel injection timing in accordance with an operating condition of the engine. The opening degree of the intake air throttle valve is reduced to accomplish rich spike control. The fuel injection timing is adjusted according to the boost pressure that develops downstream of the intake air throttle valve during rich spike control. Since the combustion tends to degrade when the boost pressure changes during rich spike control, the fuel injection timing is advanced more as the boost pressure becomes larger. This advancement of the injection timing compensates for the combustion degradation and prevents the occurrence of torque fluctuations when the opening degree of the throttle valve is adjusted during the shift to rich spike control to improve the engine operating performance.

Abstract: An engine fuel injection control system is configured to alleviate the torque fluctuation that occurs due to deviation in a pilot injection timing when the excess air ratio is changed suddenly from lean to rich. When the excess air ratio changes by a large amount, the pilot injection interval is changed in accordance with the actual excess air ratio by executing an interpolation calculation based on the target excess air ratio and the actual excess air ratio. During the transient period when the actual excess air ratio is converging toward the target excess air ratio, the pilot injection interval is changed in accordance with the change in the actual excess air ratio. As a result, it is possible to alleviate torque fluctuation by suppressing the tendency of the pilot injection interval to change rapidly in a step-like manner between target values before and after the excess air ratio changes.

Abstract: When rich spike control is executed in a diesel engine equipped with a NOx trapping catalytic converter, there are times when the amount of NOx desorbed is too little or too much. The rich spike control start timing is determined based on the NOx accumulation amount calculated during lean combustion operation and the rich spike control end timing is determined based on the NOx accumulation amount and the NOx desorption rate. Since the actual amount of NOx remaining in the NOx trapping catalytic converter can be estimated based on the NOx desorption rate during rich spike control, the rich spike control can be ended when the amount of remaining NOx reaches a prescribed target value.

Abstract: An engine fuel injection control apparatus is configured to alleviate the torque fluctuation that occurs due to deviation of the fuel injection timing from the optimum value when the excess air ratio is changed suddenly from lean to rich, such as when a NOx trapping catalytic converter is subjected to desorption and deoxidation treatment. When the excess air ratio changes by a large amount, the fuel injection timing is adjusted so as to change in accordance with the actual excess air ratio by executing an interpolation calculation based on the target excess air ratio and the actual excess air ratio. During the transient period when the actual excess air ratio is converging toward the target excess air ratio, the fuel injection timing is changed in accordance with the change in the actual excess air ratio and can therefore be set appropriately in relation to the actual excess air ratio.

Abstract: In a combustion control system of an engine employing an exhaust purifying device, a control unit determines, based on an operating condition of the exhaust purifying device, whether a request for an exhaust temperature rise is present. The control unit executes, by way of fuel injection control in presence of the request of the exhaust temperature rise, a split retard combustion mode in which a main combustion needed to produce a main engine torque and at least one preliminary combustion occurring prior to the main combustion are both achieved, and the preliminary combustion occurs near top dead center on a compression stroke, and the main combustion initiates after completion of the preliminary combustion. The control unit executes a fail-safe process that an injection timing of main fuel injection is phase-advanced, when a predicted temperature value of the exhaust purifying device exceeds a predetermined threshold value.

Abstract: An exhaust gas purifying system for an engine, including a HC trap catalyst disposed in an exhaust passage and operative to trap HC contained in the exhaust gas, and a control unit being programmed to: upon activating the HC trap catalyst after the engine is started, control a target excess air ratio to a preset value smaller than a normal value to which the target excess air ratio is controlled when the HC trap catalyst is activated, to thereby rise an exhaust gas temperature; and increase the target excess air ratio as the temperature of the HC trap catalyst rises, to thereby increase a heat quantity generated upon oxidation of the HC trapped by the HC trap catalyst.

Abstract: 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.

Abstract: In exhaust gas purifying apparatus and method for an internal combustion engine, a degree of a performance deterioration of am 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.

Abstract: In a cold condition before a warming-up completion in a diesel engine, when an engine power is less than a predetermined value, an air excess rate is controlled to a second air excess rate being smaller than a target air excess rate set after the warming-up completion, thereby promoting a warming-up of an exhaust gas purification catalyst due to rise of an exhaust gas temperature, and when the engine power is more than the predetermined value, the air excess rate is controlled to a first air excess rate being larger than the target air excess rate, thereby decreasing HC emission quantity from a combustion chamber. Accordingly, a total emission quantity of HC at the clod condition is decreased.

Abstract: 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.

Abstract: An intake air control system for an internal combustion engine is provided which comprises an intake throttle valve that controls an intake air quantity of air flowing into the engine, an EGR valve that controls a quantity of exhaust gas recirculated back to a portion of an intake system of the engine downstream of the intake throttle valve, and a control unit that controls the intake throttle valve and the EGR valve in accordance with an operating condition of the engine. The control unit includes a target opening area calculating section that calculates a target opening area of the intake throttle valve based on a target EGR ratio corresponding to the operating condition of the engine, and a control section that controls an opening degree of the intake throttle valve based on the target opening area. An intake air control method is also provided.

Abstract: 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.

Abstract: A semiconductor device includes a first pad, a second pad, a first buffer and a second buffer. The first pad is connected to another semiconductor device in a multi-chip package, and the second pad makes a probing connection in a wafer test. The first buffer drives the another semiconductor device connected to the first pad. The second buffer, being driven by the first buffer, drives a load capacitance of a tester connected to the second pad with the driving power greater than the driving power of the first buffer, and has its active/inactive state controlled by a control signal. The semiconductor device can provide the driving power necessary for the wafer test, and drive the another semiconductor device with preventing generation of drive noise and suppressing current consumption in the normal operation of the multi-chip package.