Method for the diagnosis of an air supply circuit supplying air to a burner of an exhaust gas after-treatment system for an exhaust system of an internal combustion engine

A method for the diagnosis of an air supply circuit (23) supplying air to a burner (21) of an exhaust gas after-treatment system (14) for an exhaust system (2) of an internal combustion engine (1) having an exhaust duct (10);

• the system (14) comprises at least one catalytic converter (15, 17) arranged along the exhaust duct (10) and the burner (21) is suited to introduce exhaust gases into the exhaust duct (10) to speed up the heating of said at least one catalytic converter (15, 17);
• wherein inside the burner (21) there is defined a combustion chamber (22), which receives fuel from an injector (27) and fresh air through an air supply circuit (23), which is provided with a pumping device (24) housed along a first duct (25) adjusted by a shut-off valve (26);
• the method comprises the steps of:
• housing a first pressure sensor (33) along the first duct (25) interposed between the pumping device (24) and the burner (21);
• housing a second pressure sensor (34) along a second duct (35), which connects the burner (21) to the exhaust duct (10);
• acquiring pressure signals (P33, P34) detected by said first and second pressure sensors (33, 34);
• calculating a third deviation between a frequency content of the signal acquired by the first sensor (33) and an expected development;
• wherein the expected development is determined based on a development of a control command of the pumping device (24);
• and
• recognizing a fault and/or malfunction (F), based on which an alarm signal is sent in case said third deviation is greater than a third safety value.

A method for the diagnosis of an air supply circuit (23) supplying air to a burner (21) of an exhaust gas after-treatment system (14) for an exhaust system (2) of an internal combustion engine (1) having an exhaust duct (10);

• the system (14) comprises at least one catalytic converter (15, 17) arranged along the exhaust duct (10) and the burner (21) is suited to introduce exhaust gases into the exhaust duct (10) to speed up the heating of said at least one catalytic converter (15, 17);
• wherein inside the burner (21) there is defined a combustion chamber (22), which receives fuel from an injector (27) and fresh air through an air supply circuit (23), which is provided with a pumping device (24) housed along a first duct (25) adjusted by a shut-off valve (26);
• the method comprises the steps of:
• housing a first pressure sensor (33) along the first duct (25) interposed between the pumping device (24) and the burner (21);
• housing a second pressure sensor (34) along a second duct (35), which connects the burner (21) to the exhaust duct (10);
• acquiring the pressure signals (P33, P34) detected by said first and second pressure sensors (33, 34);
• calculating a fourth deviation between a frequency content of the signal acquired by the second sensor (34) and an expected development;
• wherein the expected development is determined based on a development of a control command of the pumping device (24);
• and
• recognizing a fault (F), based on which an alarm signal is sent in case said fourth deviation is greater than a fourth safety value.

A method for the diagnosis of an air supply circuit (23) supplying air to a burner (21) of an exhaust gas after-treatment system (14) for an exhaust system (2) of an internal combustion engine (1) having an exhaust duct (10);

• the system (14) comprises at least one catalytic converter (15, 17) arranged along the exhaust duct (10) and the burner (21) is suited to introduce exhaust gases into the exhaust duct (10) to speed up the heating of said at least one catalytic converter (15, 17);
• wherein inside the burner (21) there is defined a combustion chamber (22), which receives fuel from an injector (27) and fresh air through an air supply circuit (23), which is provided with a pumping device (24) housed along a first duct (25) adjusted by a shut-off valve (26);
• the method comprises the steps of:
• housing a first pressure sensor (33) along the first duct (25) interposed between the pumping device (24) and the burner (21);
• housing a second pressure sensor (34) along a second duct (35), which connects the burner (21) to the exhaust duct (10);
• acquiring pressure signals (P33, P34) detected by said first and second pressure sensors (33, 34);
• determining a target value (PTARGET) of the pressure downstream of the pumping device (24);
• calculating a first deviation (ΔP1) through the difference between said target value (PTARGET) and the value (P33) of the pressure of the air flow supplied to the burner (21), which is detected by the first sensor (33);
• and
• recognizing a fault and/or malfunction (F), based on which an alarm signal is sent in case said first deviation (ΔP1) is greater than the first safety value (TV1).