TWO-STROKE INTERNAL COMBUSTION ENGINE

Abstract

A two-stroke internal combustion engine comprising a crankcase (2) which has a combustion chamber (3) having one or more intake ports (4) for a mixture of fuel and oxidizer and one or more exhaust ports (5) for the burnt products; an exhaust system (6) for the burnt products, in fluid communication with the exhaust port (5) of the combustion chamber (3), comprising at least one catalyst (7); the exhaust system (6) comprising a first conduit (8), along which the catalyst (7) is disposed, and a second conduit (9) having respectively an inlet (8a; 9a) and an outlet (8b; 9b), without a catalyst (7); the second conduit (9) opens into the first conduit (8) at least upstream of the catalyst (7) which is located therein;an interceptor device (10) for the burnt products exiting the exhaust port (5) of the combustion chamber (3) is configured to convey the burnt products into the first conduit (8) or into the second conduit (9). [FIG. 1];

Claims

Demands

1. A two-stroke internal combustion engine comprising a crankcase (2) having a combustion chamber (3) having one or more intake ports (4) for a mixture of fuel and oxidizer and one or more exhaust ports (5) for the burnt products; an exhaust system (6) for the burnt products, in fluid communication with the exhaust port (5) of the combustion chamber (3), comprising at least one catalyst (7); characterized in that: the exhaust system (6) comprises a first conduit (8), along which one or more catalysts (7) are disposed, and a second conduit (9), without catalysts (7), having respectively an inlet (8a; 9a) and an outlet (8b; 9b); the second conduit (9) opens into the first conduit (8) upstream of at least one catalyst (7) located therein;an intercepting device (10) for the burnt products is configured to open or close the first conduit (8) and / or the second conduit (9) so as to convey the burnt products into the first conduit (8) or into the second conduit (9).

2. Internal combustion engine according to the preceding claim, characterized in that the intercepting member (10) comprises valve means (12) and means (13) for displacing the valve means (12).

3. Internal combustion engine according to the preceding claim, characterized in that it comprises a control unit (11) configured to control means (18) for actuating means (13) for moving the intercepting member (10) according to an operating state of the internal combustion engine (1).

4. Internal combustion engine according to any one of the preceding claims, characterized in that the intercepting member (10) is configured to move from a closed condition to an open position of the second conduit (9), and vice versa.

5. Internal combustion engine according to the preceding claim, characterized in that the control unit (11) is configured for command the actuation of the intercepting device (10) to open the second conduit (9) and, after a period of time, to command the closure of the second conduit (9).

6. Internal combustion engine according to any one of the preceding claims from 1 to 3, characterized in that the intercepting member (10) is configured to go from a closed condition of the inlet mouth (8a) of the first conduit (8) to a closed condition of the inlet mouth (9a) of the second conduit (9), and vice versa.

7. Internal combustion engine according to the preceding claim, characterized in that the control unit (11) is configured to control the actuation of the interceptor member (10) to close the inlet mouth (8a) of the first conduit (8) and, after a period of time, to control the movement of the interceptor member (10) to close the inlet mouth (9a) of the second conduit (9).

8. Motor according to the preceding claim, characterized in that the valve means (12) comprise a panel (14) connected to a rotating body (15) about its own axis of rotation (15a); the rotating body (15) moves the panel (14) from a first closing position of the inlet mouth (8a) of the first conduit (8) to a second closing position of the inlet mouth (9a) of the second conduit (9), and vice versa.

9. Internal combustion engine according to the preceding claim, characterized in that the first conduit (8) and the second conduit (9) respectively have a wall (16) in contact with the panel (14).

10. Internal combustion engine according to any one of the preceding claims, characterized in that the first conduit (8) and the second conduit (9) have a respective development direction (D); these directions are convergent or parallel to each other.

11. Internal combustion engine according to any one of the preceding claims, characterized in that it comprises a sleeve (17) which connects the exhaust port (5) of the combustion chamber (3) to the first conduit (8) and to the second conduit (9).

12. Internal combustion engine according to any one of the preceding claims from 1 to 10, characterized in that the first 10 conduit (8) and the second conduit (9) come directly from the housing (2) and the intercepting device (10) is integrated into it.

13. Internal combustion engine according to any one of the preceding claims, characterized in that the actuation means (18) comprise an in-shaft starter or, alternatively, are of the remote type with cables.

14. Motorcycle comprising an internal combustion engine according to any one of claims 1 to 13.

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