An exhaust gas purification apparatus includes: a reduction catalyst converter that reduces and purifies nitrogen oxides in exhaust gas; a tank that stores a liquid reducing agent or precursor thereof; and an injection nozzle that injects the liquid reducing agent or precursor thereof stored in the tank on an exhaust gas upstream side of the reduction catalyst converter. Some of the exhaust gas flowing through an exhaust pipe is diverted to the tank by a bypass pipe, to cause an exchange of heat between the diverted exhaust gas and the liquid reducing agent or precursor thereof stored in the tank, thereby thawing the liquid reducing agent or precursor thereof frozen in the tank.

An abnormality diagnosis system of an internal combustion engine which is provided with an exhaust purification catalyst 20 which can store oxygen is provided with a downstream side air-fuel ratio sensor 41 downstream of the catalyst and a catalyst abnormality diagnosis system which uses an output air-fuel ratio of the downstream side air-fuel ratio sensor when performing active air-fuel ratio control as the basis for diagnosing an exhaust purification catalyst for abnormality. The catalyst abnormality diagnosis system uses the amount of oxygen which is stored in or released from the exhaust purification catalyst in an air-fuel ratio reversal time period in active air-fuel ratio control as the basis to calculate the maximum storable oxygen amount of the exhaust purification catalyst and uses this as the basis to diagnose the exhaust purification catalyst for abnormality.

A cooling system for a vehicle may include a cooling water temperature sensor, a cooling circulation fluid passage including first, second and third fluid passages, wherein the cooling water exhausted from the engine may be branched into the first fluid passage provided with a heater core, the second fluid passage provided with a radiator, and the third fluid passage provided with an exhaust heat recovery apparatus, a fluid flow adjusting valve provided on a point at which the cooling water passing through the cooling water temperature sensor may be branched into the first fluid passage to the third fluid passage to adjust a flow of the cooling water, and a controlling part controlling the first fluid passage to the third fluid passage to be selectively opened or closed by operating the fluid flow adjusting valve depending on the temperature of the cooling water, in a heating mode and a non-heating mode.

An oxygen sensor diagnosis control system of a hybrid electric vehicle is provided. The system of a hybrid electric vehicle eliminates an uncertainty of the number of diagnoses of an oxygen sensor and restrains diagnoses of the oxygen sensor in a hybrid electric vehicle. The system of a hybrid electric vehicle includes a hybrid controller operates a vehicle, and determines conversion of an oxygen sensor diagnosis mode based on a result obtained by calculating an oxygen sensor diagnosis index. Additionally, the controller determines whether a condition for diagnosing an oxygen sensor is satisfied when the oxygen sensor diagnosis index decreases to initiate a diagnosis inducing mode or a compulsory diagnosis mode.

An exhaust gas purification system of engine configured to classify a PM accumulation state of DPF into multiple evaluation stages based on a plurality of evaluation indices, and to repeatedly perform determination of the current evaluation stage by the current stage determination part and determination of whether to move up the current evaluation stage to the evaluation stage of the next rank by the evaluation stage determination part, wherein upon a defect of a sensor among different types of sensors being detected by the defect detection part, the current evaluation stage is newly redetermined by the current stage redetermination part as substituted for the current evaluation stage determined by the current stage determination part.

An exhaust gas aftertreatment system includes: a first sensor configured to measure a parameter in the exhaust gas aftertreatment system; a second sensor configured to measure the parameter in the exhaust gas aftertreatment system, the second sensor disposed proximate the first sensor; and at least one controller configured to simultaneously receive sensor values from the first sensor and receive sensor values from the second sensor.

An internal combustion engine comprises an exhaust purification catalyst arranged in an exhaust passage of the internal combustion engine and being able to store oxygen in inflowing exhaust gas and an air-fuel ratio sensor arranged at a downstream side of the exhaust purification catalyst in a direction of exhaust flow and detecting an air-fuel ratio of exhaust gas flowing out from the exhaust purification catalyst and stops or decreases a feed of fuel to a combustion chamber as fuel cut control. The abnormality diagnosis system calculates a characteristic of change of an air-fuel ratio based on an output air-fuel ratio output from the air-fuel ratio sensor at the time when the output air-fuel ratio first passes a part of an air-fuel ratio region of a stoichiometric air-fuel ratio or more after an end of the fuel cut control, and diagnoses abnormality of the air-fuel ratio sensor based on the characteristic of change of the air-fuel ratio. As a result, the diagnosis system can diagnose the abnormality of deterioration of response of the downstream side air-fuel ratio sensor when necessary without fail when performing fuel cut control.

In a control apparatus for an internal combustion engine in which processing of regenerating the NOx storage capacity of an NSR catalyst is carried out in accompany with processing of diagnosing an abnormality in an exhaust gas purification device including the NSR catalyst, the present invention is intended to suppress the fluctuation of torque at the time of regenerating the NOx storage capacity of the NSR catalyst, and to terminate abnormality diagnostic processing quickly. According to the invention, by setting an engine air fuel ratio, which has been set to a lean air fuel ratio before the processing of regenerating the NOx storage capacity of the NSR catalyst is started, to a weak lean air fuel ratio which is lower than a basic lean air fuel ratio and higher than a stoichiometric air fuel ratio, it becomes possible to suppress the fluctuation of torque at the time of regeneration processing being started, and to terminate abnormality diagnostic processing at an early period of time.

Nitrogen oxide multiplexing systems are provided. Various embodiments provide for systems comprising an aftertreatment component configured to treat exhaust exiting an engine, a sensor, a conduit, and a switching device. The sensor is configured to detect nitrogen oxide in the exhaust from both upstream of and downstream of an aftertreatment component. The conduit has a first end positioned upstream of the aftertreatment component and a second end communicable with the sensor positioned downstream of the aftertreatment component. The conduit receives a sample of the exhaust flowing from upstream of the aftertreatment component through the first end and delivers the sample of the exhaust to the sensor through the second end. The switching device is connected to the conduit and configurable to selectively prevent the flow of exhaust upstream of the aftertreatment component from reaching the sensor.

A method for cleaning an SCR system, wherein reducing agent is supplied to an exhaust flow upstream of an SCR catalyst (260), NO.sub.X contents of the exhaust flow are determined upstream and downstream of the SCR catalyst (260) and reducing agent crystals are removed by a high-temperature procedure. The steps are determining (s430) a ratio (K1) between NO.sub.X contents downstream and upstream of the SCR catalyst (260), raising the temperature (s440) of the exhaust flow to vaporize reducing agent crystals with a view to cleaning, determining (s450) a ratio (Kn) between respective NO.sub.X contents determined downstream and upstream of the SCR catalyst (260) at a temperature (T2) of the SCR catalyst (260) at which reducing agent crystals vaporize, comparing (s460) the ratios (K1, Kn) and using this comparison as a basis for deciding whether reducing agent crystals have been removed to an intended extent. Also a computer program product containing program code (P) for a computer (200; 210) for implementing the method according to the invention. The invention relates also to a device and a motor vehicle equipped with the device.