Exhaust system for an internal combustion engine

An exhaust system (6) for an internal combustion engine (4) and comprising:

• at least one first exhaust duct (7) which originates from the internal combustion engine (4) and has an end part (9) which ends with a first outlet opening (10) through which the exhaust gases are released into the atmosphere;
• wherein the end part (9) of the first exhaust duct (7) has at least one movable wall (16) which can be moved to different positions to vary the width of the outlet opening (10);
• a motor-driven actuator device (17), which is configured to actively move the movable wall (16) and can be electronically controlled;
• a control unit (17), which is configured to vary, by controlling the actuator device (17), the position of the movable wall (16) depending on a rotation speed of the internal combustion engine (4) and on an engine load of the internal combustion engine (4);
• a second exhaust duct (11) which originates from the first exhaust duct (7) at a junction (12) and has a second outlet opening (13) through which the exhaust gases are released into the atmosphere;
• a silencing device (14) which is arranged along the second exhaust duct (11);
• and
• a regulation valve (15), which is arranged along the first exhaust duct (7) downstream of the junction (12) from which the second exhaust duct (11) originates and is adapted to regulate the flow of exhaust gases towards the end part (9) of the first exhaust duct (7).

An exhaust system (6) for an internal combustion engine (4) and comprising:

• at least one first exhaust duct (7) which originates from the internal combustion engine (4) and has an end part (9) which ends with a first outlet opening (10) through which the exhaust gases are released into the atmosphere;
• wherein the end part (9) of the first exhaust duct (7) has at least one movable wall (16) which can be moved to different positions to vary the width of the outlet opening (10);
• a motor-driven actuator device (17), which is configured to actively move the movable wall (16) and can be electronically controlled;
• a control unit (17), which is configured to vary, by controlling the actuator device (17), the position of the movable wall (16) depending on a rotation speed of the internal combustion engine (4) and on an engine load of the internal combustion engine (4);
• and
• a regulation valve (15), which intercepts the first exhaust duct (7) and is movable between a fully open position and a fully closed position;
• wherein in the fully closed position the regulation valve (15) has a free section for the passage of the exhaust gas having a non-zero area so that the exhaust gases can pass through the regulation valve (15) even when the valve (15) is in the fully closed position.