A method for operating a petrol engine, in which air is introduced into an exhaust tract through which exhaust gas from the petrol engine can flow, bypassing the petrol engine, includes introducing the air into the exhaust tract at a point arranged downstream of a first three-way catalytic converter arranged in the exhaust tract and upstream of a second three-way catalytic converter arranged in the exhaust tract downstream of the first three-way catalytic converter, while the petrol engine is operated with a sub-stoichiometric combustion air ratio, where a desulphurization of the second three-way catalytic converter is effected.

A diesel engine high pressure SCR ventilation and voltage stabilisation system, comprising an SCR reactor (10), an air intake pipeline (20) and an exhaust pipeline (30) respectively connected to an air inlet and an exhaust outlet of the SCR reactor, a pressure difference sensing apparatus (40), and a control apparatus, a first control valve (21) being arranged on the air intake pipeline (20) and a second control valve (31) being arranged on the exhaust pipeline (30), and the control apparatus being connected to the pressure difference sensing apparatus (40), the first control valve (21), and the second control valve (31). The control apparatus controls the first and second control valves such that the pressure difference between the SCR reactor and the exhaust side of the diesel engine remains in a predetermined pressure difference range. The present system implements rapid ventilation and ensures precise control and stabilisation of pressure difference.

A method for exhaust gas aftertreatment in a gasoline engine and an exhaust gas aftertreatment system are provided. In the method, two catalytic converters arranged in the exhaust gas tract of the gasoline engine are operated in different states. A first three-way catalytic converter is operated in a slightly low-oxygen range, and a second three-way catalytic converter is operated in a slightly oxygen-rich range. Secondary air is furthermore blown into the exhaust gas tract between the two three-way catalytic converters. It is thereby possible to reduce the output of emissions of the gasoline engine to a great extent. An exhaust gas aftertreatment system is likewise explained.

Methods and systems are provided for an engine of a vehicle. In one example, a method includes activating a heater in response to an engine start request when a catalyst temperature is less than a threshold temperature.

A method for exhaust gas aftertreatment in a gasoline engine and an exhaust gas aftertreatment system are provided. In the method, two catalytic converters arranged in the exhaust gas tract of the gasoline engine are operated in different states. A first three-way catalytic converter is operated in a slightly low-oxygen range, and a second three-way catalytic converter is operated in a slightly oxygen-rich range. Secondary air is furthermore blown into the exhaust gas tract between the two three-way catalytic converters. It is thereby possible to reduce the output of emissions of the gasoline engine to a great extent. An exhaust gas aftertreatment system is likewise explained.

Methods and systems are provided for improving catalyst temperature control while reducing oxygen saturation. Secondary air is injected at a location downstream of the catalyst during selected conditions. A mixing valve position is coordinated with the air injection to improve local turbulence and thereby enhance air and fuel mixing in the exhaust passage, in at least one arrangement.

An exhaust purification system for the reduction of emissions from an exhaust stream, including an oxygen detection system; a catalyst; and an air injection system positioned between the oxygen detection system and the catalyst to inject air into the exhaust stream at designated exhaust conditions, to protect the catalyst from oxygen-deprived conditions.

An internal combustion engine includes an engine body, an HC adsorption and removal catalyst in an exhaust, including an HC adsorption layer and a catalyst layer, and having a desorption temperature of the HC from the HC adsorption layer lower than an HC removal temperature of a temperature where a rate of removal of HC at the catalyst layer is a predetermined rate or more when an air-fuel ratio of the exhaust is near the stoichiometric air-fuel ratio, and an air feed device for feeding air to the HC adsorption and removal catalyst. A control device for an internal combustion engine includes an air feed control for controlling feed air to the HC adsorption and removal catalyst when a condition stands. The condition includes the temperature of the HC adsorption and removal catalyst being the desorption temperature or more and less than the HC removal temperature.

An exhaust gas system is provided for a transport refrigeration unit (TRU) engine. The exhaust gas system includes an exhaust system. The exhaust system includes a catalyst operable in a temperature range to catalyze exhaust gas produced in the TRU engine and flown through the exhaust system. The exhaust gas system further includes temperature sensors respectively disposed to sense exhaust gas temperatures upstream of and downstream from the catalyst, at least one of first, second and third valves which are proportionally controllable to moderate amounts of air provided to the TRU engine, fuel provided to the TRU engine and air provided to the catalyst, respectively, and a controller. The controller is configured to compare sensed exhaust gas temperatures with the temperature range and issue a proportional signal to the at least one of the first, second and third valves in accordance with results of the comparison.

A vehicle comprising: an internal combustion engine configured to generate an engine torque using high-gasoline content fuel; at least one fuel injector configured to deliver the high-gasoline content fuel to a cylinder of the engine; at least one heating element configured to heat the high-gasoline content fuel prior to it being delivered to the cylinder by the fuel injector; a fuel pump connected to the heating element to supply high-gasoline to the heating element, the fuel pump being configured to pressurise the high-gasoline content fuel; and an engine controller configured to control the engine torque generated by the engine and control the fuel pressure generated by the fuel pump, the engine controller using a heated-fuel behaviour model of the engine, when the fuel is being heated by the heating element(s), to: (i) control an amount of fuel delivered by the fuel injector, the heated-fuel behaviour model causing a reduced fuel injection amount for a given engine torque relative to unheated high-gasoline content fuel; and (ii) cause a higher fuel pressure to be generated by the fuel pump relative to unheated high-gasoline content fuel.