Abstract: An object is to supply fresh air and EGR gas into a cylinder in good balance according to the required load in a naturally aspirated gasoline engine. When the operation state of the engine falls in a low load range, a control apparatus adjusts the degree of opening of the second throttle while keeping the first throttle fully open and controls EGR gas quantity by adjusting the degree of opening of the EGR valve. When the operation state falls in a middle load range, the apparatus controls EGR gas quantity by adjusting the degree of opening of the first throttle while keeping the EGR valve fully open. When the operation state falls in a high load range, the apparatus adjusts the degree of opening of the first throttle while keeping the second throttle fully open and controls EGR gas quantity by adjusting the degree of opening of the EGR valve.

Abstract: A deterioration diagnosis apparatus for an exhaust gas purification apparatus according to the invention performs an induction process when an internal combustion engine is operating at a lean air-fuel ratio, measures the air-fuel ratio of the exhaust gas flowing into the SCR catalyst and the air-fuel ratio of the exhaust gas flowing out of the SCR catalyst by the air-fuel ratio sensor during the period through which the induction process is performed, and diagnoses deterioration of the SCR catalyst based on the difference between the air-fuel ratios thus measured. The diagnosis apparatus adjusts the quantity of reducing agent supplied to a hydrogen production catalyst during the period through which the induction process is performed, taking account of the degree of deterioration of the hydrogen production catalyst.

Abstract: A cooling system includes: a first coolant passage; a second coolant passage; a pump; a radiator; a third coolant passage; a connection switching mechanism that switches between a forward flow connection state and a reverse flow connection state; a fourth coolant passage; a fifth coolant passage; and a shutoff valve configured to open/shut off the fifth coolant passage. The radiator is disposed at a location at which coolant flowing from a second end of the first coolant passage into a fourth end of the second coolant passage is not cooled in the reverse flow connection state, and coolant flowing out from the second end of the first coolant passage and the fourth end of the second coolant passage is cooled in the forward flow connection state.

Abstract: A control device for an internal combustion engine is provided. The control device includes an electronic control unit. The electronic control unit is configured to set a target air-fuel ratio to a rich air-fuel ratio from a time at which fuel cut control for terminating fuel supply to a combustion chamber during operation of the internal combustion engine is terminated to a time at which an output air-fuel ratio of a downstream-side air-fuel ratio sensor becomes a rich determination air-fuel ratio or lower, temporarily set the target air-fuel ratio to the rich air-fuel ratio after the output air-fuel ratio of the downstream-side air-fuel ratio sensor becomes the rich determination air-fuel ratio or lower, and thereafter set the target air-fuel ratio to a lean air-fuel ratio.

Abstract: A control device for an internal combustion engine, equipped with: an exhaust purification catalyst provided in the exhaust passage of the internal combustion engine and capable of absorbing oxygen; a downstream air-fuel ratio sensor provided downstream from the exhaust purification catalyst in the direction of the exhaust flow; and an engine control device that controls the internal combustion engine in response to the output from the downstream air-fuel ratio sensor. The downstream air-fuel ratio sensor is configured such that the applied voltage for which the output current is zero changes in response to the exhaust air-fuel ratio, and such that when the exhaust air-fuel ratio equals the theoretical air-fuel ratio and the applied voltage in the downstream air-fuel ratio sensor is increased, the output current increases in conjunction therewith.

Abstract: An exhaust purification system of an internal combustion engine comprising at least two exhaust treatment catalysts arranged in an engine exhaust passage, a hydrogen feed source, and a plurality of hydrogen feed passages for feeding hydrogen from the hydrogen feed source to the exhaust treatment catalysts. When warming up the exhaust treatment catalysts, hydrogen is fed from the hydrogen feed source through the corresponding hydrogen feed passage to the exhaust treatment catalyst with the larger rise of the exhaust removal rate when hydrogen is fed among the exhaust treatment catalysts.

Abstract: The exhaust purification system comprises an exhaust purification catalyst, downstream side air-fuel ratio sensor, and control device. The control device performs average air-fuel ratio control which alternately sets a target average air-fuel ratio between a rich air-fuel ratio and a lean air-fuel ratio and inter-cylinder air-fuel ratio control which controls the target air-fuel ratios of the cylinders so that the target air-fuel ratio becomes the rich air-fuel ratio at least at one cylinder among the plurality of cylinders even if the target average air-fuel ratio is set to the lean air-fuel ratio.

Abstract: When the temperature of an NSR catalyst belongs to a specified NSR temperature range and the temperature of an SCR catalyst belongs to a specified SCR temperature range, urea water is added, and specified air-fuel ratio processing relating to an air-fuel ratio of exhaust gas flowing into the NSR catalyst is executed. The specified air-fuel ratio processing includes i) a first air-fuel ratio processing to cause the air-fuel ratio of the exhaust gas flowing into the NSR catalyst to be a first lean air-fuel ratio that causes emission of occluded NOx from the NSR catalyst and ii) a second air-fuel ratio processing to cause the air-fuel ratio of the exhaust gas to be a second lean air-fuel ratio leaner than the first lean air-fuel ratio. In the specified air-fuel ratio processing, the first air-fuel ratio processing and the second air-fuel ratio processing are alternately repeated.

Abstract: A lean control, in which a target air fuel ratio is made to vary to a lean air fuel ratio and a rich air fuel ratio across a lean air fuel ratio, and a rich control, in which the target air fuel ratio is made to vary to a lean air fuel ratio and a rich air fuel ratio across a rich air fuel ratio, are alternately carried out, wherein when carrying out the lean control, a period per one time in which the target air fuel ratio becomes the lean air fuel ratio is made longer than a period per one time in which the target air fuel ratio becomes the rich air fuel ratio, and a deviation of the lean air fuel ratio from the lean air fuel ratio is made smaller than a deviation of the rich air fuel ratio from the lean air fuel ratio.

Abstract: A control device includes an electronic control unit. During deceleration of the engine, when a temperature of a three-way catalyst is equal to or higher than a predetermined temperature and execution conditions of fuel cut processing are established, the electronic control unit executes first control for closing an exhaust shutoff valve, while fuel injection and ignition are continued. When the exhaust shutoff valve reaches the closed state in the first control, the electronic control unit executes second control for bringing the engine into an intake control state in which the intake throttle is closed and an EGR valve is in a predetermined open state. In the second control, the electronic control unit executes the fuel cut processing by stopping the ignition before the engine is brought into the intake control state and stopping the fuel injection after the engine is brought into the intake control state.

Abstract: A control device for an internal combustion engine is provided with a target air-fuel ratio setting part including a first setting control part performing normal control alternately switching a target air-fuel ratio between a predetermined first lean air-fuel ratio and a predetermined first rich air-fuel ratio and a second setting control part performing control for restoration of the storage amount stopping normal control and increasing the oxygen storage amount of a second catalyst when an output air-fuel ratio of a third air-fuel ratio sensor becomes a predetermined rich judgment air-fuel ratio or less.

Abstract: An exhaust purification system comprises an exhaust purification catalyst, a downstream side air-fuel ratio sensor and a control device. The control device makes the air-fuel ratio of the exhaust gas change to an air-fuel ratio at a rich side from the prior air-fuel ratio as air-fuel ratio rich increasing control when the air-fuel ratio of the exhaust gas is made a rich air-fuel ratio and the output air-fuel ratio of the downstream side air-fuel ratio sensor is maintained at a lean judged air-fuel ratio or more, and judges that the downstream side air-fuel ratio sensor suffers from an abnormality, when, due to the air-fuel ratio rich increasing control, the air-fuel ratio of the exhaust gas is made to change to the rich side air-fuel ratio and the output air-fuel ratio of the downstream side air-fuel ratio sensor changes to the lean side.

Abstract: An exhaust gas control system includes an upstream purification device disposed in an exhaust passage of the internal combustion engine, a downstream purification device disposed in a portion of the exhaust passage downstream from the upstream purification device, a fuel addition valve disposed in a portion of the exhaust passage upstream from the upstream purification device, and a urea addition valve disposed in a portion of the exhaust passage between the upstream purification device and the downstream purification device, and a cooling device. The cooling device is configured such that refrigerant cools the fuel addition valve first and then cools the urea addition valve subsequent to the fuel addition valve.

Abstract: A first fuel addition valve disposed in a portion of a first exhaust passage upstream from a first upstream purification device, a first urea addition valve disposed in a portion of the first exhaust passage between the first upstream purification device and a first downstream purification device, and a first valve cooling passage configured such that i) refrigerant passes the first urea addition valve and the first fuel addition valve in order, and ii) the refrigerant cools the first fuel addition valve after the refrigerant cools the first urea addition valve.

Abstract: An electronic control unit (ECU) of an internal combustion engine, which includes an air-fuel ratio sensor arranged at a downstream side of an exhaust purification catalyst, is configured to judge if a state of the air-fuel ratio sensor is normal or abnormal based on the first characteristic of change of air-fuel ratio and, if a judgment cannot be made based on the first characteristic, the ECU is configured to judge if the state of the air-fuel ratio sensor is normal or abnormal based on a second characteristic of change of air-fuel ratio. As a result, it is possible to suppress the effects of the change of state of the exhaust purification catalyst while accurately diagnosing the abnormality of deterioration of response of a downstream side air-fuel ratio sensor.

Abstract: This disclosure is intended to suppress a noble metal supported by a three-way catalyst from being deteriorated by oxidation with the execution of fuel cut processing in a suitable manner. A control apparatus for a naturally aspirated gasoline engine is provided with a three-way catalyst, a first throttle valve, a second throttle valve arranged in the intake passage at the downstream side of the first throttle valve, an EGR valve, and a controller. When the controller carries out fuel cut processing and the temperature of the three-way catalyst is equal to or higher than a predetermined temperature, the controller introduces the EGR gas into a cylinder of the gasoline engine as intake air by fully closing the first throttle valve and by opening the EGR valve, and further controls an amount of the EGR gas by adjusting the degree of opening of the second throttle valve.

Abstract: An exhaust purification system comprising an exhaust purification catalyst, a downstream side air-fuel ratio sensor, and a control device performing air-fuel ratio control for controlling an air-fuel ratio of exhaust gas and abnormality diagnosis control for diagnosing the downstream side air-fuel ratio sensor. In the air-fuel ratio control, the control device alternately and repeatedly switches the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst between a rich air-fuel ratio and a lean air-fuel ratio. In the abnormality diagnosis control, the control device judges that the downstream side air-fuel ratio sensor has become abnormal when the air-fuel ratio of the exhaust gas is made the rich air-fuel ratio by the air-fuel control and the output air-fuel ratio of the downstream side air-fuel ratio sensor changes from an air-fuel ratio richer than a predetermined lean judged air-fuel ratio to an lean air-fuel ratio.

Abstract: An object is to supply fresh air and EGR gas into a cylinder in good balance according to the required load in a naturally aspirated gasoline engine. When the operation state of the engine falls in a low load range, a control apparatus adjusts the degree of opening of the second throttle while keeping the first throttle fully open and controls EGR gas quantity by adjusting the degree of opening of the EGR valve. When the operation state falls in a middle load range, the apparatus controls EGR gas quantity by adjusting the degree of opening of the first throttle while keeping the EGR valve fully open. When the operation state falls in a high load range, the apparatus adjusts the degree of opening of the first throttle while keeping the second throttle fully open and controls EGR gas quantity by adjusting the degree of opening of the EGR valve.

Abstract: An internal combustion engine includes an exhaust valve, a plurality of cams Ca, Cb, and Cc used to drive the exhaust valve, a cam-switching variable valve mechanism that selects a use cam used to drive the exhaust valve out of the plurality of cams Ca, Cb, and Cc, and an electronic control unit that determines whether switching abnormality of the use cam in the variable valve mechanism is present on the basis of a locus M in a predetermined period K which is a period in which the exhaust valve is opened. The locus M is a locus of an in-cylinder pressure changing rate dPc/d? and is specifically a locus indicating a variation of the in-cylinder pressure changing rate dPc/d? depending on a crank angle ?.

Abstract: High temperature (HT) and low temperature (LT) cooling water, the LT cooling water being at a lower temperature than the HT cooling water, circulate in HT and LT cooling water flows in respective channels. A controller controls to set the temperature of the LT cooling water lower in a case where an operating point of an engine lies in a particular region in an operational region of the engine, the particular region including a region in which the load is high and the engine speed is low, than in a case where the operating point lies in an operational region other than the particular region. Furthermore, the controller narrows the particular region in a direction toward higher loads in a case where the temperature of the HT cooling water is lower than a predetermined temperature.