Abstract: The exhaust purification device of an internal combustion engine comprises a catalyst 20 arranged in an exhaust passage and able to store oxygen; and an air-fuel ratio control device configured to control an air-fuel ratio of inflowing exhaust gas flowing into the catalyst. The air-fuel ratio control device is configured to perform a distribution forming control controlling the air-fuel ratio of the inflowing exhaust gas so that in the catalyst, a first region with an oxygen storage amount of equal to or greater than a predetermined value and a second region with an oxygen storage amount of less than the predetermined value are alternately formed along an axial direction of the catalyst. The total number of the first region and the second region formed by the distribution forming control is equal to or greater than three.

Abstract: The exhaust purification device of an internal combustion engine comprises a catalyst 20 arranged in an exhaust passage and able to store oxygen; and an air-fuel ratio control device configured to control an air-fuel ratio of inflowing exhaust gas flowing into the catalyst. The air-fuel ratio control device is configured to perform a distribution forming control controlling the air-fuel ratio of the inflowing exhaust gas so that in the catalyst, a first region with an oxygen storage amount of equal to or greater than a predetermined value and a second region with an oxygen storage amount of less than the predetermined value are alternately formed along an axial direction of the catalyst. The total number of the first region and the second region formed by the distribution forming control is equal to or greater than three.

Abstract: An object is to prevent a wrong diagnosis from being made in diagnosis of an NOx sensor provided downstream of an SCR catalyst. A diagnosis apparatus is applied to an NOx sensor provided in an exhaust system including an SCR catalyst, a reducing agent supply device, an NOx sensor, an exhaust gas purification device provided upstream of the SCR catalyst, and a controller configured to raise the temperature of the exhaust gas purification device and control supply of reducing agent so as to adjust the ammonia adsorption amount to a specific amount. The controller is further configured to perform diagnosis of the NOx sensor on the basis of the concentration of ammonia slipping out of the SCR catalyst and disallow diagnosis of the NOx sensor since the ammonia adsorption amount is adjusted to the specific amount until a specific time elapses.

Abstract: In a control system for an internal combustion engine in which an exhaust gas purification catalyst having a lower catalyst layer and an upper catalyst layer disposed at the upper side of the lower catalyst layer is arranged in an exhaust passage of the internal combustion engine, when an operation at a rich air fuel ratio is switched to an operation at a target lean air fuel ratio, switching is made through a first operation in which the air fuel ratio of exhaust gas is temporarily made into a lean air fuel ratio, and a second operation which is carried out after the first operation and in which the air fuel ratio of the exhaust gas is made to change alternately between the rich air fuel ratio and the lean air fuel ratio a plurality of times, whereby the HC poisoning of the catalyst can be recovered at an early stage.

Abstract: An object is to prevent a wrong diagnosis from being made in diagnosis of an NOx sensor provided downstream of an SCR catalyst. A diagnosis apparatus is applied to an NOx sensor provided in an exhaust system including an SCR catalyst, a reducing agent supply device, an NOx sensor, an exhaust gas purification device provided upstream of the SCR catalyst, and a controller configured to raise the temperature of the exhaust gas purification device and control supply of reducing agent so as to adjust the ammonia adsorption amount to a specific amount. The controller is further configured to perform diagnosis of the NOx sensor on the basis of the concentration of ammonia slipping out of the SCR catalyst and disallow diagnosis of the NOx sensor since the ammonia adsorption amount is adjusted to the specific amount until a specific time elapses.

Abstract: An object is to estimate the responsiveness of an exhaust gas sensor with as high accuracy as possible and to determine abnormality in the responsiveness of the exhaust gas sensor accurately. A diagnosis apparatus for the exhaust gas sensor comprises a controller configured to perform oxygen concentration control to change the oxygen concentration in the exhaust gas, calculate a responsiveness index correlating with the responsiveness of the exhaust gas sensor by diving the largest value of an absolute change rate defined as the absolute value of the change rate of the output signal of the exhaust gas sensor during a reference period by the difference between the value of the output signal at the time when the absolute change rate becomes largest and the converged value of the output signal with the reference period, and estimate the responsiveness of said exhaust gas sensor on the basis of said responsiveness index.

Abstract: In a control system that includes a pressure accumulating portion that supplies CNG to a fuel injection valve and a regulator that adjusts a pressure in the pressure accumulating portion to a set pressure and of which a valve element opens when CNG is supplied to the pressure accumulating portion and closes when supply of CNG to the pressure accumulating portion is shut off, a control parameter relating to a combustion state in an internal combustion engine is controlled on the basis of a length of a period during which an opening degree of the valve element reduces from a first predetermined opening degree to a second predetermined opening degree when the pressure in the pressure accumulating portion is adjusted to the set pressure by the regulator.

Abstract: In a control system for an internal combustion engine in which an exhaust gas purification catalyst having a lower catalyst layer and an upper catalyst layer disposed at the upper side of the lower catalyst layer is arranged in an exhaust passage of the internal combustion engine, when an operation at a rich air fuel ratio is switched to an operation at a target lean air fuel ratio, switching is made through a first operation in which the air fuel ratio of exhaust gas is temporarily made into a lean air fuel ratio, and a second operation which is carried out after the first operation and in which the air fuel ratio of the exhaust gas is made to change alternately between the rich air fuel ratio and the lean air fuel ratio a plurality of times, whereby the HC poisoning of the catalyst can be recovered at an early stage.

Abstract: An object of the invention is to provide a technology pertaining to a control system for an internal combustion engine using CNG to allow an internal combustion engine to operate appropriately even when properties of CNG change. To achieve the object, in the control system for an internal combustion engine using compressed natural gas according to the invention, when air-fuel ratio feedback control that corrects the fuel injection quantity in such a way as to make the air-fuel ratio of the air-fuel mixture burned in the internal combustion engine substantially equal to a target air-fuel ratio, a control parameter relating to a condition of combustion of the air-fuel mixture is corrected based on the magnitude of the correction value in the air-fuel ratio feedback control.

Abstract: The present invention resides in a control apparatus for an internal combustion engine in which selective use is made of a case where a first fuel, being easy to be ignited, is caused to combust by itself, and a case where a second fuel, being hard to be ignited, is also caused to combust by igniting the first fuel, and which is provided with an acquisition unit configured to acquire a combustion state of the second fuel in the case where the second fuel is also caused to combust by igniting the first fuel, and a decision unit configured to decide amounts of supply of the first fuel and the second fuel to be supplied to the internal combustion engine on and after next time, based on the combustion state of the second fuel determined by the acquisition unit.

Abstract: The present invention is intended to suppress generation of a misfire and an increase in the amount of emission of HC, in a multi-fuel internal combustion engine of compression ignition type using, as fuels, a liquid fuel which can be ignited by compression and a gas fuel which is lower in ignitability than the liquid fuel. In the invention, in the same operating state, in cases where the liquid fuel and the gas fuel are caused to combust with the liquid fuel being used as an ignition source, the equivalent ratio of a mixture in a cylinder is made to increase, in comparison with the case where only the liquid fuel is caused to combust, and the rate of the increase of the equivalent ratio with respect to the case where only the liquid fuel is caused to combust is made smaller, when an engine load is low in comparison with the time when the engine load is high, and when an engine rotational speed is low in comparison with the time when the engine rotational speed is high.

Abstract: An object of the present invention is to restrain the emission amount of unburned fuel components while restraining the consumption of fuel with relatively high ignitability in a multi-fuel internal combustion engine. The present invention resides in such a fuel supply control system for a multi-fuel internal combustion engine that a first fuel with relatively high ignitability and a second fuel with relatively low ignitability are used as fuels and the first fuel is used as an ignition source to mixedly combust the first fuel and the second fuel, wherein a supply amount Qd of the first fuel is adjusted on the basis of a difference ?RH between a first heat generation rate RHd which is a heat generation rate given when assuming that only the first fuel is combusted and an actual heat generation rate RHa which is a heat generation rate given when the fuels are actually combusted (S105 to 107, S109).

Abstract: The present invention has been made in view of the above-mentioned problems, and is intended to carry out ignition to a mixture in a more stable manner in a multi-fuel internal combustion engine. In the control apparatus for a multi-fuel internal combustion engine which is able to be operated by mixed combustion of a plurality of kinds of fuels, a mixing ratio of the plurality of kinds of fuels is controlled by a mixing ratio control unit, and ignition timing of a spark plug is controlled by an ignition timing control unit, in such manner that a required discharge voltage is made equal to or less than a voltage which is lower by a fixed value than a voltage to be applied to said spark plug (S104, S108).

Abstract: The present invention is intended to suppress an excessive increase in the amount of emission of HC in a multi-fuel internal combustion engine of compression ignition type which is able to perform mixed combustion of a liquid fuel, which can be ignited by compression, and a gas fuel which has methane as a primary component. In the present invention, a required mixing ratio of the liquid fuel and the gas fuel as well as a required amount of HC emission is calculated based on an operating state of the multi-fuel internal combustion engine (S103, S104). Then, based on the required mixing ratio and the required amount of HC emission, a required compression ratio is calculated which is a compression ratio at which an amount of HC emission from the multi-fuel internal combustion engine becomes the required amount of HC emission (S105), and the compression ratio of the multi-fuel internal combustion engine is controlled to the required compression ratio (S107).

Abstract: An object of the present invention is to reduce the difference between the torque generated by an internal combustion engine and a required torque in a control system for a multifuel internal combustion engine that can use CNG and liquid fuel. To achieve the object, the control system for an internal combustion engine according to the present invention causes the internal combustion engine to operate in a first operation mode in which only CNG is used, when the required torque of the internal combustion engine is equal to or lower than a threshold and to operate in a second operation mode in which at least liquid fuel among CNG and liquid fuel is used, when the required torque of the internal combustion engine is higher than the threshold and changes the magnitude of the threshold in conjunction with the concentration of inert gases contained in CNG.

Abstract: The present invention is intended to suppress, in an exhaust gas purification system for an internal combustion engine capable of mixing and combusting liquid fuel and compressed natural gas, an excessive rise in temperature of an exhaust gas purification device at the time when the exhaust gas purification device is caused to regenerate. In the exhaust gas purification system for an internal combustion engine according to the present invention, when the liquid fuel and the compressed natural gas are caused to mix and combust in the internal combustion engine at the time of regenerating the exhaust gas purification device, an amount of HC to be supplied to the exhaust gas purification device from an HC supply device is decreased in comparison with the time when only the liquid fuel is caused to combust in the internal combustion engine.

Abstract: In a control system that includes a pressure accumulating portion that supplies CNG to a fuel injection valve and a regulator that adjusts a pressure in the pressure accumulating portion to a set pressure and of which a valve element opens when CNG is supplied to the pressure accumulating portion and closes when supply of CNG to the pressure accumulating portion is shut off, a control parameter relating to a combustion state in an internal combustion engine is controlled on the basis of a length of a period during which an opening degree of the valve element reduces from a first predetermined opening degree to a second predetermined opening degree when the pressure in the pressure accumulating portion is adjusted to the set pressure by the regulator.

Abstract: An object of the present invention is to provide a technology with which when a gaseous fuel is supplied into a fuel tank of a vehicle with an internal combustion engine that uses gaseous fuel, properties of the supplied gaseous fuel can be determined promptly. To achieve the object, the fuel property determination system for a vehicle equipped with an internal combustion engine using gaseous fuel according to the present invention is adapted to calculate, when gaseous fuel is supplied to the fuel tank, the gas constant of the supplied gaseous fuel using a cross sectional area of a passage for delivering gaseous fuel to the fuel tank from a filler port and a change in the pressure in the fuel tank as parameters and to calculate the concentration of inert gases contained in the gaseous fuel using the gas constant as a parameter.

Abstract: An object of the invention is to provide a technology pertaining to a control system for an internal combustion engine using CNG to allow an internal combustion engine to operate appropriately even when properties of CNG change. To achieve the object, in the control system for an internal combustion engine using compressed natural gas according to the invention, when air-fuel ratio feedback control that corrects the fuel injection quantity in such a way as to make the air-fuel ratio of the air-fuel mixture burned in the internal combustion engine substantially equal to a target air-fuel ratio, a control parameter relating to a condition of combustion of the air-fuel mixture is corrected based on the magnitude of the correction value in the air-fuel ratio feedback control.

Abstract: The present invention is intended to suppress generation of a misfire and an increase in the amount of emission of HC, in a multi-fuel internal combustion engine of compression ignition type using, as fuels, a liquid fuel which can be ignited by compression and a gas fuel which is lower in ignitability than the liquid fuel. In the invention, in the same operating state, in cases where the liquid fuel and the gas fuel are caused to combust with the liquid fuel being used as an ignition source, the equivalent ratio of a mixture in a cylinder is made to increase, in comparison with the case where only the liquid fuel is caused to combust, and the rate of the increase of the equivalent ratio with respect to the case where only the liquid fuel is caused to combust is made smaller, when an engine load is low in comparison with the time when the engine load is high, and when an engine rotational speed is low in comparison with the time when the engine rotational speed is high.