An EHC line leakage diagnosis method can operate a heater of an oxygen detector when satisfying one or more conditions of an engine off time, a coolant temperature, and an outside air temperature by a diagnosis controller upon the key-on of the non-operation of an engine, and then, determine the normality or abnormality of a temperature drop using a change in a temperature value of a signal value and the temperature value detected by the oxygen detector after an air pump is driven, and then confirm the leakage of an exhaust line and a line on the rear end portion of an EHC valve of an air line using the number of times of the occurrence of the abnormality of the temperature drop, and can perform the failure diagnosis without generating the exhaust gas by not operating an engine.

An exhaust gas aftertreatment system for an internal combustion engine, which comprises an exhaust system which can be connected to the outlet of an internal combustion engine. A catalytic converter close to the engine and a second catalytic converter arranged downstream of the catalytic converter in an underbody of a motor vehicle are provided in the flow direction of an exhaust gas from the internal combustion engine flowing through an exhaust gas duct of the exhaust system. An inlet point for secondary air, an exhaust gas burner, and a fuel injector for introducing fuel into the exhaust gas duct are arranged downstream of the catalytic converter close to the engine and upstream of the second catalytic converter. According to the invention, the exhaust gas burner is activated immediately after the internal combustion engine is started in order to heat the second catalytic converter to its light-off temperature. Once the second catalytic converter has reached its light-off temperature, secondary air and fuel are additionally introduced into the exhaust gas duct and are exothermically reacted on the second catalytic converter in order to support the heating of the second catalytic converter.

An exhaust gas aftertreatment system for an internal combustion engine, which comprises an exhaust system which can be connected to the outlet of an internal combustion engine. A catalytic converter close to the engine and a second catalytic converter arranged downstream of the catalytic converter in an underbody of a motor vehicle are provided in the flow direction of an exhaust gas from the internal combustion engine flowing through an exhaust gas duct of the exhaust system. An inlet point for secondary air, an exhaust gas burner, and a fuel injector for introducing fuel into the exhaust gas duct are arranged downstream of the catalytic converter close to the engine and upstream of the second catalytic converter. According to the invention, the exhaust gas burner is activated immediately after the internal combustion engine is started in order to heat the second catalytic converter to its light-off temperature. Once the second catalytic converter has reached its light-off temperature, secondary air and fuel are additionally introduced into the exhaust gas duct and are exothermically reacted on the second catalytic converter in order to support the heating of the second catalytic converter.

The present utility model application refers to a new constructive arrangement introduced in acoustic filter of hermetic compressor, and more particularly, a new constructive arrangement that optimizes the suction flow of the acoustic filter, which is normally arranged within the hermetic housing of the hermetic compressor. The suction acoustic filter (1) is composed by at least one outlet pipe (2), outlet pipe (2) comprising at least two independent suction outlets (21). Each independent suction outlet (21) extending along outlet pipe (2).

An exhaust gas aftertreatment system for an internal combustion engine, which comprises an exhaust system which can be connected to the outlet of an internal combustion engine. A catalytic converter close to the engine and a second catalytic converter arranged downstream of the catalytic converter in an underbody of a motor vehicle are provided in the flow direction of an exhaust gas from the internal combustion engine flowing through an exhaust gas duct of the exhaust system. An inlet point for secondary air, an exhaust gas burner, and a fuel injector for introducing fuel into the exhaust gas duct are arranged downstream of the catalytic converter close to the engine and upstream of the second catalytic converter. According to the invention, the exhaust gas burner is activated immediately after the internal combustion engine is started in order to heat the second catalytic converter to its light-off temperature. Once the second catalytic converter has reached its light-off temperature, secondary air and fuel are additionally introduced into the exhaust gas duct and are exothermically reacted on the second catalytic converter in order to support the heating of the second catalytic converter.

An exhaust gas aftertreatment system for an internal combustion engine, which comprises an exhaust system which can be connected to the outlet of an internal combustion engine. A catalytic converter close to the engine and a second catalytic converter arranged downstream of the catalytic converter in an underbody of a motor vehicle are provided in the flow direction of an exhaust gas from the internal combustion engine flowing through an exhaust gas duct of the exhaust system. An inlet point for secondary air, an exhaust gas burner, and a fuel injector for introducing fuel into the exhaust gas duct are arranged downstream of the catalytic converter close to the engine and upstream of the second catalytic converter. According to the invention, the exhaust gas burner is activated immediately after the internal combustion engine is started in order to heat the second catalytic converter to its light-off temperature. Once the second catalytic converter has reached its light-off temperature, secondary air and fuel are additionally introduced into the exhaust gas duct and are exothermically reacted on the second catalytic converter in order to support the heating of the second catalytic converter.

The invention relates to an exhaust gas aftertreatment system for a spark ignition internal combustion engine based on the Otto principle. The internal combustion engine is connected on the outlet side to an exhaust gas system, wherein an electrically heatable three-way catalytic converter, a four-way catalytic converter downstream from the electrically heatable three-way catalytic converter, and a further three-way catalytic converter downstream from the four-way catalytic converter are situated in the exhaust gas system in the flow direction of an exhaust gas through the exhaust gas system. Before the internal combustion engine is started, the electrically heatable three-way catalytic converter and preferably also the four-way catalytic converter are heated to allow efficient exhaust gas aftertreatment of the untreated emissions of the internal combustion engine upon starting the internal combustion engine. The exhaust gas aftertreatment system is also configured to allow efficient conversion of the pollutants also during a regeneration of the four-way catalytic converter, and thus, to ensure particularly low emissions in all operating states of the motor vehicle.

An EHC line leakage diagnosis method can operate a heater of an oxygen detector when satisfying one or more conditions of an engine off time, a coolant temperature, and an outside air temperature by a diagnosis controller upon the key-on of the non-operation of an engine, and then, determine the normality or abnormality of a temperature drop using a change in a temperature value of a signal value and the temperature value detected by the oxygen detector after an air pump is driven, and then confirm the leakage of an exhaust line and a line on the rear end portion of an EHC valve of an air line using the number of times of the occurrence of the abnormality of the temperature drop, and can perform the failure diagnosis without generating the exhaust gas by not operating an engine.

An EHC line leakage diagnosis method can operate a heater of an oxygen detector when satisfying one or more conditions of an engine off time, a coolant temperature, and an outside air temperature by a diagnosis controller upon the key-on of the non-operation of an engine, and then, determine the normality or abnormality of a temperature drop using a change in a temperature value of a signal value and the temperature value detected by the oxygen detector after an air pump is driven, and then confirm the leakage of an exhaust line and a line on the rear end portion of an EHC valve of an air line using the number of times of the occurrence of the abnormality of the temperature drop, and can perform the failure diagnosis without generating the exhaust gas by not operating an engine.

Aspects of the present disclosure include a casing comprising an air inlet and an air outlet, a fan configured to move air from the air inlet to the air outlet, and a tunable sound attenuating module having an opening at a first end of the tunable sound attenuating module, a cavity, and a back wall at a second end of the tunable sound attenuating module, wherein: the tunable sound attenuating module is oriented such that the back wall is closer to the fan than the opening, and a length of tunable sound attenuating module is substantially one fourth of the acoustic wavelength of a sound generated by the fan.