A NOx sensor control device is connected to a NOx sensor mounted in an internal combustion engine. The NOx sensor has a detection cell configured to detect a NOx concentration and having a solid electrolyte body and a pair of electrodes provided on a surface of the solid electrolyte body and a heater heating the detection cell. The NOx sensor control device has a heater control unit. The heater control unit is configured to, at a time when an operation of the internal combustion engine stops, perform a recovery control of the NOx sensor which is an electric current control of the heater for removing SOx adsorbed to the NOx sensor.

An ECU 30 calculates a target temperature of a bed temperature of a DOC 22a under PM regeneration control at each control period by the elements M1 to M9. Among these elements, the estimating section M7 estimates a passing SO.sub.3 amount at each control period by using an inflow SOx amount and a representative temperature. The estimating section M8 estimates a SO.sub.2 reduction rate, which is a ratio of reduction from SO.sub.3 to SO.sub.2 in the DOC 22a. Then, the calculating unit M9 calculates an amount of SO.sub.3 that is allowed to desorb from the DOC 22a as an allowable desorption SO.sub.3 amount at each control period, by using a constrained SO.sub.3 amount which corresponds to a constraint concerning sulfate white smoke, the passing SO.sub.3 amount, and the SO.sub.2 reduction rate.

Disclosed is an exhaust gas aftertreatment system (1) for a diesel engine, the exhaust gas aftertreatment system comprising: a treatment agent tank (2) for storing an exhaust gas treatment agent; a metering injection module (4), with the injection of the metering injection module (4) being controlled with a determined duty ratio signal according to a desired injection amount; a supply module (3) connected between the treatment agent tank (2) and the metering injection module (4) for supplying the exhaust gas treatment agent to the metering injection module (4); an exhaust gas treatment agent pipe (6) connected between the metering injection module (4) and the supply module (3); a pressure sensor for measuring the system pressure in the exhaust gas treatment agent pipe (6); and a controller (7); wherein the controller (7) is configured to receive a system pressure signal from the pressure sensor during injection of the metering injection module (4), and detect an injection abnormality of the metering injection module (4) based on at least a first amount, which represents an actual injection amount and is determined by the system pressure signal, and a second amount, which represents a theoretical injection amount and is determined by a corresponding duty ratio signal. A corresponding injection abnormality detection method is further disclosed. The injection abnormality detection method is simple and reliable.

A controller alternately repeats a desorption process of desorbing sulfur compound deposited on an NSR catalyst by supplying fuel from a direct injection valve to exhaust gas, and a pausing process of pausing fuel supply from the injection valve to the exhaust gas. The controller executes a cooling fuel addition for adding engine fuel from the addition valve of the exhaust passage to cool the addition valve during execution of the pausing process, and prohibit the cooling fuel addition during execution of the desorption process. The controller calculates a target temperature of the addition valve at the time of start of the desorption process such that the temperature of the addition valve during execution of the desorption process does not exceed an allowable upper limit temperature and calculates the addition amount at the time of cooling fuel addition.

A control apparatus and a control method for an internal combustion engine of the present invention integrates an operating time in a state in which temperature TCAT of an exhaust gas purification catalyst is lower than a first temperature, to obtain first integrated time IT1, senses oxygen storage capacity OSC of the exhaust gas purification catalyst, and has a regeneration treatment of sulfur poisoning carried out when first integrated time IT1 exceeds first time THT1 and oxygen storage capacity OSC falls below first capacity OSC1, and furthermore, integrates an operating time in a state in which temperature TCAT of the exhaust gas purification catalyst is higher than second temperature TCAT2, to obtain second integrated time IT2, and has a regeneration treatment of oxidation poisoning carried out when second integrated time IT2 exceeds second time THT2.

A control apparatus for an internal combustion engine is provided. The control apparatus includes a temperature sensor and an electronic control unit. The temperature sensor is configured to detect the temperature of an exhaust gas control apparatus. The electronic control unit is configured to: estimate a sulfuric compound accumulation amount on the exhaust gas control apparatus; and when a specific condition in which the sulfuric compound accumulation amount is equal to or larger than a predetermined accumulation amount and the temperature of the exhaust gas control apparatus is equal to or higher than a predetermined temperature or more is satisfied, control an intake air amount adjuster such that an intake air amount when the specific condition is satisfied is increased as compared to the intake air amount when the specific condition is not satisfied in the same operation state.

An ECU 30 calculates a target temperature of a bed temperature of a DOC 22a under PM regeneration control at each control period by the elements M1 to M9. Among these elements, the estimating section M7 estimates a passing SO.sub.3 amount at each control period by using an inflow SOx amount and a representative temperature. The estimating section M8 estimates a SO.sub.2 reduction rate, which is a ratio of reduction from SO.sub.3 to SO.sub.2 in the DOC 22a. Then, the calculating unit M9 calculates an amount of SO.sub.3 that is allowed to desorb from the DOC 22a as an allowable desorption SO.sub.3 amount at each control period, by using a constrained SO.sub.3 amount which corresponds to a constraint concerning sulfate white smoke, the passing SO.sub.3 amount, and the SO.sub.2 reduction rate.

An integrated system for onboard scrubbing of a marine exhaust gas on a ship, comprising: a) a Venturi quencher having: i) two liquid inlets that feed quench water to the Venturi quencher; and ii) a hot exhaust gas entry that feeds the hot marine exhaust gas from an engine on the ship; and b) the rotating packed bed device, having: iii) a stationary gas distributor, placed along an outer circumference of the RPB device, that disengages a quenched marine exhaust gas from a cooled two-phase mixture, and uniformly distributes the quenched marine exhaust gas along the outer circumference of the RPB device; and iv) a stationary liquid distributor, centrally positioned, and with multiple liquid rings that are fitted with spray nozzles that spray a seawater along an inner circumference of the RPB device. Also, processes for using the integrated system, and a ship comprising the integrated system.

An aftertreatment system comprises a SCR system including a catalyst formulated to decompose constituents of an exhaust gas passing therethrough. A filter is positioned upstream of the SCR system. The filter comprises a sulfur suppressing compound formulated to reduce an amount of SOx gases included in the exhaust gas flowing through the aftertreatment system. In particular embodiments, the filter comprises a filter housing and a filter element positioned within the filter housing. The filter element comprises the sulfur suppressing compound.

Gas treatment systems and processes for reducing tail gas emissions such as SO.sub.2, SO.sub.3, H.sub.2SO.sub.4, NOx, HC, CO, and other pollutants are provided. The processes include transferring tail gas from at least one source of tail gas to at least one destination sulphuric acid plant via a tail gas transfer system, wherein the tail gas replaces or supplements one or more of the combustion gas, air feed, dilution gas, and quench gas used by the destination sulphuric acid plant. The systems include at least one destination sulphuric acid plant and a tail gas transfer system for transferring tail gas from at least one source of tail gas to the at least one destination sulphuric acid plant. The systems and processes described herein may be used to eliminate start-up emissions and/or convert sulphur-containing species present in tail gas emissions into commercial H.sub.2SO.sub.4.