A catalyst activation method and a catalyst activation device are provided which can activate a NOx catalyst efficiently in an ensured fashion. A plurality of accessories are connected to an internal combustion engine, and a control mechanism is provided on each of the accessories for controlling a load to be exerted on the internal combustion engine by driving the corresponding accessory. Then, a temperature of a NOx catalyst is acquired, and when the acquired temperature of the NOx catalyst is lower than a catalyst activation temperature, in order to drive additionally a certain number of accessories in the plurality of accessories which correspond to the temperature difference, the controlling mechanism(s) which corresponds to the accessory(ies) to be driven additionally is controlled to drive the corresponding accessory(ies) so as to increase a load to be exerted on the internal combustion engine.

It is an object to make it possible to burn and remove particulate matter without generating runaway even if the particulate matter is excessively accumulated at the time of regeneration of an exhaust gas purification device. A common rail engine and the exhaust gas purification device placed in an exhaust gas path of the engine are provided. A plurality of regeneration controls for burning and removing the particulate matter accumulated in the exhaust gas purification device can be executed. The plurality of regeneration controls include at least non-operation regeneration control for raising exhaust gas temperature by combining post injection (E) and predetermined high speed rotation speed, and recovery regeneration control which can be executed when the non-operation regeneration control fails. In the non-operation regeneration control and the recovery regeneration control, the engine is driven exclusively for burning and removing the particulate matter. The recovery regeneration control is carried out at exhaust gas temperature lower than that of the non-operation regeneration control while taking time longer than that of the non-operation regeneration control.

A transport refrigeration system (10) includes a refrigerant vapor compression transport unit (12) including a compressor (14). A drive unit is utilized to provide power to the compressor. The drive unit includes a diesel powered engine (32) and a diesel particulate filter in operable communication with the diesel powered engine to filter combustion particulates from an exhaust gas output from the diesel powered engine. An air control valve is in operable communication with the diesel powered engine to control a flow of air into an air inlet of the diesel powered engine, thereby controlling an exhaust gas temperature of the diesel engine to aid in regeneration of the diesel particulate filter.

An object is to enable an exhaust gas purification system to bring about satisfactory oxidation of fuel in an oxidation catalyst in a temperature raising process of a filter, thereby allowing fuel supply to be performed at as low a temperature as possible. In the exhaust gas purification system, when the temperature of the exhaust gas flowing into the oxidation catalyst exceeds a specific threshold temperature that is determined based on the cetane number of fuel, a controller performs the temperature raising process. If the quantity of heat generated in the oxidation catalyst per unit time is smaller than a specific value while the temperature raising process is being performed, the temperature raising process in progress is suspended. The temperature raising process is resumed later on when the temperature of the exhaust gas flowing into the oxidation catalyst exceeds an updated threshold temperature higher than the specific threshold temperature.

A system is provided and includes a fuel module that, based on a crankshaft angle of an engine, generates a value indicative of an amount of fuel burned in a cylinder or a change in the amount of fuel burned. A heat release module, based on the value, determines an amount of heat released during a combustion event of the cylinder. A pressure module, based on the amount of heat released, estimates a pressure in the cylinder. A temperature module, based on the pressure, estimates a temperature in the cylinder. A concentration module, based on the pressure or the temperature, estimates nitrogen oxide concentration levels in the cylinder. An output module, based on the nitrogen oxide concentration levels, estimates an amount of nitrogen oxides. A control module, based on the amount of nitrogen oxides out of the cylinder, controls operation of the engine or an exhaust system.

A method is disclosed for operating an aftertreatment system having a diesel particulate filter of an internal combustion engine of an automotive system. A regeneration event of the diesel particulate filter is started. The presence of an object ahead of the automotive system is detected. A value of a deceleration that the automotive system should perform in order to avoid a collision with the object is determined. A temperature of the diesel particulate filter is reduced if the value of the deceleration is greater than a first predetermined threshold value.

A method is disclosed for regulating an exhaust after-treatment (AT) system for a diesel engine. The method includes detecting the engine's cold start when the engine's exhaust gas flow directed into the AT system is at a temperature below a threshold value. The method also includes determining flow-rates of the engine's exhaust gas and its fuel supply. The method additionally includes determining a magnitude of exhaust gas energy using the determined exhaust gas flow-rates and the fuel supply over an elapsed time following the cold start. The method also includes integrating a detected temperature of the exhaust gas over the elapsed time and comparing the determined magnitude of exhaust gas energy with the integrated temperature. Furthermore, the method includes regulating operation of the AT system using the determined exhaust gas temperature when the determined magnitude of exhaust gas energy is within a predetermined value of the integrated exhaust gas temperature.

A method for regenerating an exhaust gas filter for vehicles includes controlling an engine to operate in a high RPM range by a controller and regenerating the exhaust gas filter, controlling the engine to operate in the high RPM range by a temperature sensor unit provided on an exhaust pipe, controlling the engine to operate in a middle RPM range above a measured exhaust gas temperature threshold, and controlling the engine to operate in the middle RPM range by the temperature sensor unit, and controlling the engine to operate in an idle state if the temperature of the exhaust gas measured by the temperature sensor unit in secondary measurement is a middle RPM escape temperature predetermined by the controller or lower.

Methods and systems are provided for treatment of an exhaust stream that comprises nitrogen oxides NO.sub.x. The method comprises supplying a first additive to the exhaust stream as a first reduction of a first amount of nitrogen oxides NO.sub.x.sub._.sub.1 reaching a first device, arranged to impact the first amount of nitrogen oxides NO.sub.x.sub._.sub.1. The method also comprises supplying a second additive to the exhaust stream, which is used as a second reduction of a second amount of nitrogen oxides NO.sub.x.sub._.sub.2 reaching a second device, arranged to reduce the second amount of nitrogen oxides NO.sub.x.sub._.sub.2. At least one of the first supply and the second supply is controlled, based on a total ability for the first device to provide the first reduction, and for the second device to provide the second reduction, so that a required total reduction on the nitrogen oxides NO.sub.x in the exhaust stream is provided.

An exhaust treatment system comprising: a first oxidation catalyst to oxidize nitrogen- and/or hydrocarbon compounds in an exhaust stream; a first dosage device downstream of said first oxidation catalyst to supply a first additive into said exhaust stream; a first reduction catalyst device, arranged downstream of said first dosage device, including a slip-catalyst primarily for reduction of nitrogen oxides (NOx), and secondarily for oxidation of additive; a second oxidation catalyst arranged downstream of said first reduction catalyst; a particulate filter arranged downstream of said oxidation catalyst; a second dosage device, arranged downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device, arranged downstream of said second dosage device for reduction of nitrogen oxides in said exhaust stream, with the use of at least one of said first and said second additive.