A deterioration determination apparatus is usable with an ammonia sensor that includes an ammonia element portion that includes, a solid electrolyte, an ammonia electrode, and a reference electrode. The deterioration determining apparatus compares a first evaluation value and a second evaluation value, and determines whether deterioration has occurred in the ammonia element portion of the ammonia sensor at an evaluation time or subsequent to the evaluation time. The first evaluation value is based on a first sensor current obtained when a DC voltage is applied between the ammonia electrode and the reference electrode of the ammonia element portion at an initial time that is during an initial use period of the ammonia sensor. The second evaluation value is based on a second sensor current obtained when the DC voltage is applied between the ammonia electrode and the reference electrode subsequent to the initial period of use of the ammonia sensor.

Provided are an exhaust purification device and an exhaust purification method which can achieve improved fuel efficiency. The exhaust purification device (100) is equipped with: a DOC (5) for occluding hydrocarbons in an exhaust gas; a DPF (6) that is provided downstream from the DOC (5) and is for trapping particulate matter in the exhaust gas; and an ECU (10) for determining, in accordance with the amount of occluded hydrocarbons in the DOC (5), a start time for a regeneration process for removing particulate matter accumulated in the DPF (6).

An exhaust gas system includes an exhaust gas pipe through which exhaust gas flows in a flow direction and which has a pipe wall. A flange is arranged in the pipe wall and has a passage opening provided with an internal thread. A gas sensor, in particular a particle sensor, is provided for sensing the concentration of soot particles contained in the exhaust gas and has a threaded housing portion that is provided with an external thread and is screwed into the passage opening. An annular gap is produced between a radial outer face of the threaded housing portion and a passage-opening inner circumferential portion which protrudes into the interior of the exhaust gas pipe. The flange has a flow guiding element which extends over a downstream part of the circumference of the threaded housing portion and which is provided for limiting or largely preventing a flow around the gas sensor in the annular gap.

Methods and systems are provided for an ultrasonic wave generator within a vehicle emissions control system. In one example, a frequency of ultrasonic waves may be applied to a fuel vapor canister, the frequency adjusted in response to an estimate of hydrocarbon distribution within a vapor canister received from temperature and hydrocarbon sensor outputs.

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.

A straddle-type vehicle comprises an engine which generates driving power and emits an exhaust gas; an exhaust device including: a catalyst which cleans the exhaust gas, an inner tube in which the catalyst is disposed and through which the exhaust gas flows, the inner tube extending to a location downstream of the catalyst; and an outer tube which covers an outer peripheral surface of the inner tube in an axial direction of the inner tube, and has a muffling space through which the exhaust gas discharged from the inner tube is flowed to reduce an exhaust noise radiated from the engine; at least one exhaust pipe through which the exhaust gas is led to the catalyst; and a downstream oxygen sensor which detects an oxygen concentration of the exhaust gas after flowing through the catalyst, at a location downstream of the catalyst in the inner tube.

A system includes an internal combustion engine having a number of cylinders, with at least one of the cylinder(s) being a primary EGR cylinder that is dedicated to provided EGR flow during at least some operating conditions. A controller is structured to control combustion conditions in the cylinders in response to one or more operating conditions associated with the engine.

A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.

A torque request module determines a torque request for an engine based on a driver input. A cylinder control module determines a target fraction of a total number of cylinders of the engine to be activated based on the torque request. An air fuel imbalance (AFIM) module selectively commands that the cylinder control module set the target fraction based on a predetermined fraction of the total number of cylinders of the engine to be activated. The cylinder control module further: sets the target fraction based on the predetermined fraction in response to the command; and activates and deactivates opening of intake and exhaust valves of the cylinders of the engine based on the target fraction. The AFIM module further, while the target firing fraction is set based on the predetermined fraction, selectively diagnoses the presence of an AFIM fault based on samples of a signal from an oxygen sensor.

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.