Abstract: A particulate matter sensor and a particulate matter sensing system using such a sensor are provided which are capable of being produced at decreased cost and accurately measuring the temperature of a heater. The particulate matter sensor includes a deposition portion on which particulate matter contained in exhaust gas is accumulated, a pair of electrodes which are disposed on the deposition portion and separate from each other, a heater which heats the deposition portion, and a pair of heater leads which form a path through which electrical current is delivered to the heater. A sensing line is connected to at least one of the heater leads to measure a resistance of the heater lead.

Abstract: An exhaust gas filter purifies exhaust gas containing particulate matter emitted from an engine. The filter has cell walls and cells surrounded by the cell walls. Through pores formed in the cell walls, adjacent cells are communicated. The cells have open cells opening along an axial direction of the filter, and plugged cells. An upstream end part of the plugged cell is plugged by a plug member. On a cross section perpendicular to the axial direction, a flow-passage sectional area of the plugged cells is larger than a flow-passage sectional area of the open cells. A total length of the filter is not less than a first standard value and is not more than a critical length Lm determined by respective predetermined equations.

Abstract: A catalytic conversion characteristic of a catalyst, which indicates a relationship between an air-to-fuel ratio and a catalytic conversion efficiency of the catalyst, includes a second air-to-fuel ratio point, which is a point of starting an outflow of NOx from the catalyst and is located on a rich side of a first air-to-fuel ratio point that forms an equilibrium point for a rich component and oxygen. A constant current circuit, which induces a flow of an electric current from an exhaust side electrode to an atmosphere side electrode through a solid electrolyte layer in a sensor element, is connected to the sensor element. A microcomputer controls a current value of the electric current, which is induced by the constant current circuit, based on a difference between the first air-to-fuel ratio point and the second air-to-fuel ratio point at the catalyst.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer calculates an element resistance, determines whether the air-fuel ratio is at least rich, lean, or stoichiometric, on the basis of a comparison between an electromotive force output of the electrogenic cell and a prescribed threshold. Further, the microcomputer controls the constant current supplied by the constant current circuit on the basis of the element resistance.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, in which a NOx absorbing catalyst and a NOx concentration sensor for detecting a NOx concentration in exhaust gases of the engine, are provided in an exhaust passage of the engine. A rich spike for temporarily enriching the air-fuel ratio is performed, and an execution timing of the rich spike is determined based on a detected output from the NOx concentration sensor. Performing the rich spike is determined to be unnecessary during a reducing state period from the time the rich spike ends to the time a preset time period has elapsed, and is also determined to be unnecessary when a change tendency of the detected output is determined to be an output decreasing state where the detected output is decreasing.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer calculates a resistance value (element resistance) of the sensor element, and performs a restriction on the constant current supplied by the constant current circuit on the basis of the element resistance.

Abstract: A particulate matter sensor and a particulate matter sensing system using such a sensor are provided which are capable of being produced at decreased cost and accurately measuring the temperature of a heater. The particulate matter sensor includes a deposition portion on which particulate matter contained in exhaust gas is accumulated, a pair of electrodes which are disposed on the deposition portion and separate from each other, a heater which heats the deposition portion, and a pair of heater leads which form a path through which electrical current is delivered to the heater. A sensing line is connected to at least one of the heater leads to measure a resistance of the heater lead.

Abstract: An exhaust purification device purifies an exhaust gas exhausted from an internal combustion engine. The exhaust purification device has a three-way catalytic agent that is located in an exhaust passage of the internal combustion engine and a particulate filter that is located downstream of the three-way catalytic agent in the exhaust passage and that collects an exhaust particulate. The particulate filter is provided with cells that includes sealed-inlet cells of which upstream ends are sealed and through cells through which an upstream side and a downstream side of the particulate filter communicate with each other. The particulate filter is arranged at a location where a temperature of the exhaust gas reaching an upstream end of the particulate filter is higher than or equal to a combustion temperature of the exhaust particulate, when the three-way catalytic agent is in an active state and when the internal combustion engine is operated.

Abstract: A catalytic conversion characteristic of a catalyst, which indicates a relationship between an air-to-fuel ratio and a catalytic conversion efficiency of the catalyst, includes a second air-to-fuel ratio point, which is a point of starting an outflow of NOx from the catalyst and is located on a rich side of a first air-to-fuel ratio point that forms an equilibrium point for a rich component and oxygen. A constant current circuit, which induces a flow of an electric current from an exhaust side electrode to an atmosphere side electrode through a solid electrolyte layer in a sensor element, is connected to the sensor element. A microcomputer controls a current value of the electric current, which is induced by the constant current circuit, based on a difference between the first air-to-fuel ratio point and the second air-to-fuel ratio point at the catalyst.

Abstract: An exhaust purification device purifies an exhaust gas exhausted from an internal combustion engine. The exhaust purification device has a three-way catalytic agent that is located in an exhaust passage of the internal combustion engine and a particulate filter that is located downstream of the three-way catalytic agent in the exhaust passage and that collects an exhaust particulate. The particulate filter is provided with cells that includes sealed-inlet cells of which upstream ends are sealed and through cells through which an upstream side and a downstream side of the particulate filter communicate with each other. The particulate filter is arranged at a location where a temperature of the exhaust gas reaching an upstream end of the particulate filter is higher than or equal to a combustion temperature of the exhaust particulate, when the three-way catalytic agent is in an active state and when the internal combustion engine is operated.

Abstract: An exhaust gas filter purifies exhaust gas containing particulate matter emitted from an engine. The filter has cell walls and cells surrounded by the cell walls. Through pores formed in the cell walls, adjacent cells are communicated. The cells have open cells opening along an axial direction of the filter, and plugged cells. An upstream end part of the plugged cell is plugged by a plug member. On a cross section perpendicular to the axial direction, a flow-passage sectional area of the plugged cells is larger than a flow-passage sectional area of the open cells. A total length of the filter is not less than a first standard value and is not more than a critical length Lm determined by respective predetermined equations.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes. The solid electrolyte layer is held between the electrodes. The electrodes include an atmosphere side electrode, which becomes a positive side at a time of outputting an electromotive force from the sensor element, and an exhaust side electrode, which becomes a negative side at the time of outputting the electromotive force from the sensor element. A resistor is provided in an electric path that connects between the atmosphere side electrode and a ground. When the sensor element generates the electromotive force, the resistor conducts an electric current, which is generated while using the electromotive force as an electric power source, to induce a change in an output characteristic of the O2 sensor.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes. The solid electrolyte layer is held between the electrodes, which includes an atmosphere side electrode and an exhaust side electrode. A constant current circuit is installed in an electric path, which connects between the atmosphere side electrode and a ground, to induce a flow of a predetermined constant electric current between the electrodes through the solid electrolyte layer. When the sensor element generates an electromotive force, the constant current circuit conducts an electric current, which is generated while using the electromotive force of the sensor element as an electric power source, to induce the flow of the predetermined constant electric current between the electrodes in an electromotive force range, which is equal to or larger than an electromotive force of the sensor element generated at a stoichiometric air-to-fuel ratio.

Abstract: A catalytic conversion characteristic of a catalyst, which indicates a relationship between an air-to-fuel ratio and a catalytic conversion efficiency of the catalyst, includes a second air-to-fuel ratio point, which is a point of starting an outflow of NOx from the catalyst and is located on a rich side of a first air-to-fuel ratio point that forms an equilibrium point for a rich component and oxygen. A constant current circuit, which induces a flow of an electric current from an exhaust side electrode to an atmosphere side electrode through a solid electrolyte layer in a sensor element, is connected to the sensor element. A microcomputer controls a current value of the electric current, which is induced by the constant current circuit, based on a difference between the first air-to-fuel ratio point and the second air-to-fuel ratio point at the catalyst.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, in which a NOx absorbing catalyst and a NOx concentration sensor for detecting a NOx concentration in exhaust gases of the engine, are provided in an exhaust passage of the engine. A rich spike for temporarily enriching the air-fuel ratio is performed, and an execution timing of the rich spike is determined based on a detected output from the NOx concentration sensor. Performing the rich spike is determined to be unnecessary during a reducing state period from the time the rich spike ends to the time a preset time period has elapsed, and is also determined to be unnecessary when a change tendency of the detected output is determined to be an output decreasing state where the detected output is decreasing.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes. The solid electrolyte layer is held between the electrodes, which includes an atmosphere side electrode and an exhaust side electrode. A constant current circuit is installed in an electric path, which connects between the atmosphere side electrode and a ground, to induce a flow of a predetermined constant electric current between the electrodes through the solid electrolyte layer. A voltage circuit is installed in an electric path, which connects between the exhaust side electrode and a ground, to increase an electric potential of the exhaust side electrode by a predetermined amount relative to an electric potential at an output side of the constant current circuit, from which the electric current flows out of the constant current circuit.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer calculates a resistance value (element resistance) of the sensor element, and performs a restriction on the constant current supplied by the constant current circuit on the basis of the element resistance.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer calculates an element resistance, determines whether the air-fuel ratio is at least rich, lean, or stoichiometric, on the basis of a comparison between an electromotive force output of the electrogenic cell and a prescribed threshold. Further, the microcomputer controls the constant current supplied by the constant current circuit on the basis of the element resistance.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes. The solid electrolyte layer is held between the electrodes, which includes an atmosphere side electrode and an exhaust side electrode. A constant current circuit is installed in an electric path, which connects between the atmosphere side electrode and a ground, to induce a flow of a predetermined constant electric current between the electrodes through the solid electrolyte layer. When the sensor element generates an electromotive force, the constant current circuit conducts an electric current, which is generated while using the electromotive force of the sensor element as an electric power source, to induce the flow of the predetermined constant electric current between the electrodes in an electromotive force range, which is equal to or larger than an electromotive force of the sensor element generated at a stoichiometric air-to-fuel ratio.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes. The solid electrolyte layer is held between the electrodes, which includes an atmosphere side electrode and an exhaust side electrode. A constant current circuit is installed in an electric path, which connects between the atmosphere side electrode and a ground, to induce a flow of a predetermined constant electric current between the electrodes through the solid electrolyte layer. A voltage circuit is installed in an electric path, which connects between the exhaust side electrode and a ground, to increase an electric potential of the exhaust side electrode by a predetermined amount relative to an electric potential at an output side of the constant current circuit, from which the electric current flows out of the constant current circuit.