Heating device for an exhaust system of an internal combustion engine

A heating device (6) for an exhaust system (1) of an internal combustion engine (2);

• the heating device (6) comprises:
• a main tubular body (12), which contains a combustion chamber (7) delimited by a first base wall (14) and by a second base wall (15), which are opposite one another;
• a fuel injector (9) configured to inject fuel;
• one single inlet opening (19), which can be connected to a fan (8) to receive an air flow, which is directed to the combustion chamber (7) and gets mixed with fuel;
• a spark plug (10), which is mounted through a side wall (16) of the main tubular body (12) to trigger the combustion of a mixture of air and fuel;
• and
• a mixing chamber (18), which is arranged beside the combustion chamber (7), is separated from the combustion chamber (7) by the first base wall (14), receives air from the inlet opening (19) and receives fuel from the fuel injector (9);
• wherein the mixing chamber (18) receives air directly from the inlet opening (19), which leads into the mixing chamber (18);
• wherein a secondary tubular body (23) is provided, which is arranged inside the main tubular body (12) and inside the combustion chamber (7), is directly connected to the first base wall (14) and has a side wall (24), which is arranged at a given distance from the side wall (16) of the main tubular body (12) so as to divide an initial part of the combustion chamber (7) into a central zone (25), which is located inside the secondary tubular body (23), and an annular peripheral zone (26), which is located around the secondary tubular body (23);
• wherein the first base wall (14) has at least one central passage opening (27) configured to lead fuel and part of the air flow into the secondary tubular body (23) in the central zone (25) of the combustion chamber (7) and has at least one peripheral passage opening (28) configured to lead a remaining part of the air flow to the outside of the secondary tubular body (23) in the annular peripheral zone (26) of the combustion chamber (7);
• wherein is it provided a first converging nozzle (29), which engages the central passage opening (27) of the first base wall (14), establishes a communication between the mixing chamber (18) and the central zone (25) of the combustion chamber (7) and is arranged partly inside the mixing chamber (18) and partly inside the central zone (25) of the combustion chamber (7);
• and
• wherein a second converging nozzle (32) is provided which is coaxial to the first converging nozzle (29) and is arranged inside the first converging nozzle (29);
• wherein a tubular containing element (37) is provided which goes through a third base wall (22) facing and opposite the first base wall (14) and houses, on the inside, an end part of the fuel injector (9).

A heating device (6) for an exhaust system (1) of an internal combustion engine (2);

• the heating device (6) comprises:
• a main tubular body (12), which contains a combustion chamber (7) delimited by a first base wall (14) and by a second base wall (15), which are opposite one another;
• a fuel injector (9) configured to inject fuel;
• one single inlet opening (19), which can be connected to a fan (8) to receive an air flow, which is directed to the combustion chamber (7) and gets mixed with fuel;
• a spark plug (10), which is mounted through a side wall (16) of the main tubular body (12) to trigger the combustion of a mixture of air and fuel;
• and
• a mixing chamber (18), which is arranged beside the combustion chamber (7), is separated from the combustion chamber (7) by the first base wall (14), receives air from the inlet opening (19) and receives fuel from the fuel injector (9);
• wherein the mixing chamber (18) receives air directly from the inlet opening (19), which leads into the mixing chamber (18);
• wherein a secondary tubular body (23) is arranged inside the main tubular body (12) and inside the combustion chamber (7), is directly connected to the first base wall (14) and has a side wall (24), which is arranged at a given distance from the side wall (16) of the main tubular body (12) so as to divide an initial part of the combustion chamber (7) into a central zone (25), which is located inside the secondary tubular body (23), and an annular peripheral zone (26), which is located around the secondary tubular body (23);
• wherein the first base wall (14) has at least one central passage opening (27) configured to lead fuel and part of the air flow into the secondary tubular body (23) in the central zone (25) of the combustion chamber (7) and has at least one peripheral passage opening (28) configured to lead a remaining part of the air flow to the outside of the secondary tubular body (23) in the annular peripheral zone (26) of the combustion chamber (7);
• wherein a third base wall (22) is provided which faces and is opposite the first base wall (14), is fixed to an end of the main tubular body (12) and axially delimits the mixing chamber (18) on the opposite side relative to the first base wall (14).

A heating device (6) for an exhaust system (1) of an internal combustion engine (2);

• the heating device (6) comprises:
• a main tubular body (12), which contains a combustion chamber (7) delimited by a first base wall (14) and by a second base wall (15), which are opposite one another;
• a fuel injector (9) configured to inject fuel;
• one single inlet opening (19), which can be connected to a fan (8) to receive an air flow, which is directed to the combustion chamber (7) and gets mixed with fuel;
• a spark plug (10), which is mounted through a side wall (16) of the main tubular body (12) to trigger the combustion of a mixture of air and fuel;
• and
• a mixing chamber (18), which is arranged beside the combustion chamber (7), is separated from the combustion chamber (7) by the first base wall (14), receives air from the inlet opening (19) and receives fuel from the fuel injector (9);
• wherein the mixing chamber (18) receives air directly from the inlet opening (19), which leads into the mixing chamber (18);
• wherein a secondary tubular body (23) is arranged inside the main tubular body (12) and inside the combustion chamber (7), is directly connected to the first base wall (14) and has a side wall (24), which is arranged at a given distance from the side wall (16) of the main tubular body (12) so as to divide an initial part of the combustion chamber (7) into a central zone (25), which is located inside the secondary tubular body (23), and an annular peripheral zone (26), which is located around the secondary tubular body (23);
• wherein the first base wall (14) has at least one central passage opening (27) configured to lead fuel and part of the air flow into the secondary tubular body (23) in the central zone (25) of the combustion chamber (7) and has at least one peripheral passage opening (28) configured to lead a remaining part of the air flow to the outside of the secondary tubular body (23) in the annular peripheral zone (26) of the combustion chamber (7);
• wherein the secondary tubular body (23) has an axial length (L2), which ranges from 40% to 60% of an axial length (L1) of the combustion chamber (7);
• and
• wherein the secondary tubular body (23) has a maximum diameter (D2), which ranges from 75% to 90% of a maximum diameter (D1) of the combustion chamber (7).

A heating device (6) for an exhaust system (1) of an internal combustion engine (2);

• the heating device (6) comprises:
• a main tubular body (12), which contains a combustion chamber (7) delimited by a first base wall (14) and by a second base wall (15), which are opposite one another;
• a fuel injector (9) configured to inject fuel;
• one single inlet opening (19), which can be connected to a fan (8) to receive an air flow, which is directed to the combustion chamber (7) and gets mixed with fuel;
• a spark plug (10), which is mounted through a side wall (16) of the main tubular body (12) to trigger the combustion of a mixture of air and fuel;
• and
• a mixing chamber (18), which is arranged beside the combustion chamber (7), is separated from the combustion chamber (7) by the first base wall (14), receives air from the inlet opening (19) and receives fuel from the fuel injector (9);
• wherein the mixing chamber (18) receives air directly from the inlet opening (19), which leads into the mixing chamber (18);
• wherein a secondary tubular body (23) is arranged inside the main tubular body (12) and inside the combustion chamber (7), is directly connected to the first base wall (14) and has a side wall (24), which is arranged at a given distance from the side wall (16) of the main tubular body (12) so as to divide an initial part of the combustion chamber (7) into a central zone (25), which is located inside the secondary tubular body (23), and an annular peripheral zone (26), which is located around the secondary tubular body (23);
• wherein the first base wall (14) has at least one central passage opening (27) configured to lead fuel and part of the air flow into the secondary tubular body (23) in the central zone (25) of the combustion chamber (7) and has at least one peripheral passage opening (28) configured to lead a remaining part of the air flow to the outside of the secondary tubular body (23) in the annular peripheral zone (26) of the combustion chamber (7);
• wherein the peripheral passage opening (28) of the first base wall (14) is sized so that the air flow rate flowing through the peripheral passage opening (28) is greater than the air flow rate flowing through the central passage opening (27).