Two-stroke internal combustion engines and motorcycles including such two-stroke internal combustion engines

Abstract

This invention provides a two-stroke internal combustion engine and a motorcycle including the two-stroke internal combustion engine, wherein the two-stroke internal combustion engine includes: a crankcase having a combustion chamber having one or more intake ports for receiving a mixture of fuel and oxidant and one or more exhaust ports for discharging combustion products; an exhaust system for discharging combustion products in fluid communication with the exhaust ports of the combustion chamber, the exhaust system including at least one catalytic converter. The exhaust system includes a first pipe along which the catalytic converter is disposed and a second pipe without the catalytic converter, the first pipe and the second pipe being respectively provided with an inlet and an outlet; the second pipe entering the first pipe upstream of the catalytic converter located at least in the first pipe; and a shut-off unit for combustion products exiting the exhaust ports of the combustion chamber being configured to guide the combustion products into the first pipe or the second pipe.

Description

Technical Field

[0001] This utility model relates to a two-stroke internal combustion engine and a motorcycle including the two-stroke internal combustion engine. Background Technology

[0002] To date, due to strict pollution control regulations, two-stroke internal combustion engines have been used less frequently in road sports.

[0003] Approval of two-stroke internal combustion engines requires increasingly stringent and difficult-to-meet emission limits.

[0004] It is worth noting that although a catalytic converter is used at the engine exhaust port, the key to emissions is the engine cold start, because the air / fuel mixture is particularly fuel-rich in the first few minutes of operation to facilitate the start-up itself, and the catalytic converter is inefficient before reaching its optimal operating temperature.

[0005] Another adverse situation regarding emissions was discovered under low-temperature conditions.

[0006] The presence of an air-rich / fuel mixture and the low operating temperature of the catalytic converter result in the emission of large amounts of unburned hydrocarbons (called "HC", which contains hydrogen (H) and carbon (C) atoms) into the atmosphere.

[0007] In this context, it is necessary to develop solutions that improve upon existing technologies to meet emission requirements and regulations. Utility Model Content

[0008] This objective is achieved entirely through the two-stroke internal combustion engine disclosed in this article:

[0009] According to one aspect of the present invention, a two-stroke internal combustion engine is provided, comprising: a crankcase having a combustion chamber having one or more intake ports for receiving a mixture of fuel and oxidant and one or more exhaust ports for discharging combustion products; an exhaust system for discharging the combustion products in fluid communication with the exhaust ports of the combustion chamber, the exhaust system including at least one catalytic converter. The exhaust system includes a first conduit and a second conduit, one or more catalytic converters being disposed along the first conduit, the second conduit having no catalytic converter, the first conduit and the second conduit being respectively provided with an inlet and an outlet; the second conduit opening into the first conduit upstream of at least one catalytic converter located in the first conduit; and a shut-off unit for the combustion products being configured to open or close the first conduit and / or the second conduit to guide the combustion products into the first conduit or the second conduit.

[0010] Optionally, the above-mentioned two-stroke internal combustion engine has one or more of the following features:

[0011] The shut-off unit includes a valve device and a drive device for driving the valve device;

[0012] The internal combustion engine includes a control unit configured to control an actuator for actuating the drive unit to move the shut-off unit according to the operating state of the internal combustion engine;

[0013] The shut-off unit is configured to switch from the closed state of the second pipe to the open state of the second pipe, or vice versa;

[0014] The control unit is configured to command the shut-off unit to open the second pipe, and after a certain period of time, command the second pipe to close.

[0015] The shut-off unit is configured to switch from a closed state at the inlet of the first pipe to a closed state at the inlet of the second pipe, or vice versa;

[0016] The control unit is configured to command the shut-off unit to close the inlet of the first pipe, and after a certain period of time, command the shut-off unit to close the inlet of the second pipe;

[0017] The valve device includes a plate connected to a rotating member that rotates about its own axis of rotation; the rotating member moves the plate from a first position where it closes the inlet of the first pipe to a second position where it closes the inlet of the second pipe, or vice versa;

[0018] The first pipe and the second pipe each include opposing walls for abutting against the disc-shaped plate;

[0019] The first pipe and the second pipe each have a corresponding extending direction, which are either converging or parallel to each other;

[0020] The internal combustion engine includes a pipe fitting that connects the exhaust port of the combustion chamber to the first pipe and the second pipe;

[0021] The first and second pipes branch off directly from the crankcase, and the shut-off is integrated therein;

[0022] The actuation device includes a coaxial motor, or alternatively, a wired remote type.

[0023] According to another aspect of the present invention, a motorcycle is provided, which includes the above-described two-stroke internal combustion engine. Attached Figure Description

[0024] The advantages of this invention will become clear through an indicative and therefore non-limiting description of embodiments of a two-stroke internal combustion engine disclosed only by way of non-limiting examples, wherein:

[0025] Figure 1 This is a schematic perspective view of a two-stroke internal combustion engine according to the present invention, in which some components have been removed to better highlight the other components;

[0026] Figure 2 It is a schematic 3D view showing the details of the image;

[0027] Figure 3 yes Figure 2 A schematic cross-section;

[0028] Figure 4 yes Figure 2 A schematic perspective view of the implementation variations of the details in the diagram;

[0029] Figure 5 yes Figure 4 A schematic cross-section;

[0030] Figures 6 to 8 Schematic illustration Figures 1 to 4 Variations and Figure 1 Two other variations of the engine exhaust system design. Detailed Implementation

[0031] The attached figure, labeled 1, indicates a two-stroke internal combustion engine.

[0032] The internal combustion engine 1 in this manual is a single-cylinder engine.

[0033] The internal combustion engine 1 includes a crankcase 2 with a combustion chamber 3.

[0034] The combustion chamber 3 has one or more intake ports 4 for receiving a mixture of fuel and oxidant, and one or more exhaust ports 5 for discharging combustion products.

[0035] An exhaust system 6 for discharging combustion products, which is in fluid communication with the exhaust port 5 of the combustion chamber 3, includes at least one catalytic converter 7.

[0036] In the disclosed embodiments, there are multiple catalytic converters 7 arranged sequentially to each other.

[0037] This embodiment has three catalytic converters 7.

[0038] The exhaust system 6 includes a first pipe 8 and a second pipe 9. One or more catalytic converters 7 are arranged along the first pipe 8, and the second pipe 9 does not have catalytic converters 7. The first pipe 8 and the second pipe 9 are respectively provided with inlets (8a; 9a) and outlets (8b; 9b).

[0039] The outlet 8b of the first pipe 8 is the exhaust port of the exhaust system 6.

[0040] The outlet 9b of the second pipe 9 enters the first pipe 8 upstream of at least the catalytic converter 7 arranged in the first pipe 8.

[0041] The shut-off unit 10 for the combustion products exiting the exhaust port 5 of the combustion chamber 3 is configured to guide the combustion products into the first pipe 8 or the second pipe 9.

[0042] exist Figure 6 In the embodiment, the shut-off unit 10 is arranged upstream of the first pipe 8 and the second pipe 9.

[0043] In such an implementation, the shut-off unit 10 is configured to switch from a closed state of the inlet 8a of the first pipe 8 to a closed state of the inlet 9a of the second pipe 9, or vice versa.

[0044] In other words, the shut-off unit 10 for the combustion products leaving the exhaust port 5 is configured to selectively shut off the inlet 8a of the first pipe 8 or the inlet 9a of the second pipe 9 in order to guide the combustion products into the first pipe 8 or the second pipe 9.

[0045] Advantageously, this allows combustion products to be directed to either the first conduit 8 or the second conduit 9 depending on the operating state of the internal combustion engine 1.

[0046] During normal operation of the internal combustion engine 1, the combustion products are directed into the first conduit 8 to pass through the catalytic converter 7 or a series of catalytic converters 7 present therein; the shut-off unit 10 shuts off the inlet 9a of the second conduit 9.

[0047] When the internal combustion engine 1 is started, the shut-off unit 10 shuts off the inlet 8a of the first pipe 8 in order to direct the combustion products toward the catalytic converter 7.

[0048] Such a catalytic converter 7 is arranged close to the crankcase 2 of the internal combustion engine 1, and heats up faster than other catalytic converters, and processes combustion products more efficiently for the catalytic process.

[0049] The control unit 11 is configured to shut down the actuator 18 of the unit 10 according to the operating state of the internal combustion engine 1.

[0050] The control unit 11 is configured to command the actuation device 18 of the shut-off unit 10 to close the inlet 8a of the first pipe 8, and after a certain period of time, command the shut-off unit 10 to move from the inlet 8a of the first pipe 8 to the inlet 9a of the second pipe 9 in order to close it.

[0051] This time length is a function of the time required for the catalytic converter 7 to reach its operating conditions.

[0052] The duration of this time can depend on the characteristics of the internal combustion engine 1 and the catalytic converter 7.

[0053] The shut-off unit 10 includes a valve device 12 and a drive device 13 for moving the valve device 12.

[0054] The valve device 12 can be of any type, such as rotary, throttling, or any other type.

[0055] According to one embodiment, the valve device 12 includes a plate 14 connected to the rotating member 15 about a rotation axis 15a of the rotating member 15, such as... Figure 3 and Figure 5 As shown.

[0056] Such a plate 14 is preferably disc-shaped, that is, other different shapes are not excluded.

[0057] The rotating member 15 moves the plate 14 from a first closed position that closes the inlet 8a of the first pipe 8 to a second closed position that closes the inlet 9a of the second pipe 9, or vice versa.

[0058] The transition from the first position to the second position and from the second position to the first position occurs by means of the plate 14 oscillating about the axis of rotation 15a of the rotating member 15 according to the first rotation direction and the second rotation direction opposite to the first direction.

[0059] It is worth noting that, during use, plate 14 is positioned at the closed position of the inlet 9a of the second pipe 9.

[0060] When the internal combustion engine 1 is running, the rotating component 15 moves the plate 14 from the second position to the first position to close the inlet 8a of the first pipe 8.

[0061] Therefore, the combustion products are directly transported to the catalytic converter 7.

[0062] This operating condition occurs, for example, during engine startup or under low ambient temperature conditions.

[0063] The drive unit 13 is, for example, in the form of a pneumatic and / or electromechanical device.

[0064] The control unit 11 commands the actuator 18 to actuate the drive unit 13.

[0065] This actuation device 18 includes an aligned starter.

[0066] Alternatively, the actuator 18 is cable-operated.

[0067] To ensure the sealing of plate 14, the first pipe 8 and the second pipe 9 each have abutment walls 16 for abutting against plate 14.

[0068] Advantageously, the abutment between the plate and the opposing wall 16 is frontal, rather than radial.

[0069] According to one embodiment variation, the abutment 16 is an annular wall.

[0070] According to one embodiment, pipe fitting 17 connects the exhaust port 5 of combustion chamber 3 to the first pipe 8 and the second pipe 9.

[0071] Therefore, this first implementation is in the form of a three-way valve.

[0072] According to a variation, the first pipe 8 and the second pipe 9 branch off directly from the crankcase 2 and the shut-off unit 10 is integrated therein.

[0073] The first pipe 8 and the second pipe 9 have corresponding extension directions D.

[0074] Such directions D converge ( Figure 2 and Figure 3 or parallel to each other ( Figure 4 and Figure 5 ).

[0075] Direction D changes its angular position relative to each other within a range of 0° to 45° (including the endpoints).

[0076] According to a variant, namely Figure 7 The shut-off unit 10 is arranged in a section of the second pipe 9.

[0077] In this variation, the shut-off unit 10 is configured to transition from the closed state of that segment of the second pipe 9 to the open state of that segment, or vice versa.

[0078] During normal operation of the internal combustion engine 1, the combustion products are guided into the first conduit 8 to pass through the catalytic converter 7 or a series of catalytic converters 7 present therein; the shut-off unit 10 shuts off a section of the second conduit 9 where the shut-off unit 10 is installed.

[0079] When the internal combustion engine is running, the shut-off unit 10 is turned on, allowing the combustion products to be guided toward the catalytic converter 7 into the second pipe 9.

[0080] Similarly, in this embodiment, the shut-off unit 10 includes a valve device 12 and a drive device 13 for moving the valve device 12.

[0081] The control unit 11 is configured to actuate the actuation device 18 of the shut-off unit 10 according to the operating state command of the internal combustion engine 1.

[0082] When the internal combustion engine is running (e.g., when the engine is starting, under low temperature conditions), the control unit 11 is configured to command the second pipe 9 to open by actuating the drive device 13 for moving the valve device 12.

[0083] After a period of time, the control unit 11 is configured to command the second pipe 9 to close by actuating the drive device 13 for moving the valve device 12.

[0084] according to Figure 8 In a variant of the first pipe 8, the shut-off unit 10 is arranged in a section of the first pipe 8.

[0085] In this variant, the shut-off unit 10 is configured to transition from an open state of that segment of the first pipe 8 to a closed state, or vice versa.

[0086] During normal operation of the internal combustion engine 1, the combustion products are guided into the first conduit 8 to pass through the catalytic converter 7 or a series of catalytic converters 7 present therein; the shut-off unit 10 keeps the first conduit 8 open at a section where the shut-off unit 10 is installed.

[0087] When the internal combustion engine is running, the shut-off unit 10 enters the shut-off state, causing the combustion products to be guided toward the catalytic converter 7 into the second pipe 9.

[0088] Similarly, in this embodiment, the shut-off unit 10 includes a valve device 12 and a drive device 13 for moving the valve device 12.

[0089] The control unit 11 is configured to actuate the actuation device 18 of the shut-off unit 10 according to the operating state command of the internal combustion engine 1.

[0090] When the internal combustion engine is running (e.g., when the engine is starting, under low temperature conditions), the control unit 11 is configured to command the first pipe 8 to close by actuating the drive device 13 for moving the valve device 12.

[0091] After a period of time, the control unit 11 is configured to command the first pipe 8 to open by actuating the drive device 13 for moving the valve device 12.

[0092] Another objective of this invention is to provide a motorcycle that includes a two-stroke internal combustion engine 1.

Claims

1. A two-stroke internal combustion engine, comprising: A crankcase (2) having a combustion chamber (3) having one or more intake ports (4) for receiving a mixture of fuel and oxidant and one or more exhaust ports (5) for discharging combustion products. An exhaust system (6) for discharging the combustion products, which is in fluid communication with the exhaust port (5) of the combustion chamber (3), includes at least one catalytic converter (7). Its features are, The exhaust system (6) includes a first pipe (8) and a second pipe (9), one or more catalytic converters (7) are arranged along the first pipe (8), and the second pipe (9) does not have catalytic converters (7). The first pipe (8) and the second pipe (9) are respectively provided with an inlet and an outlet. The second pipe (9) is introduced into the first pipe (8) upstream of at least one catalytic converter (7) located in the first pipe (8); The shut-off unit (10) for the combustion products is configured to open or close the first pipe (8) and / or the second pipe (9) to guide the combustion products into the first pipe (8) or the second pipe (9).

2. The two-stroke internal combustion engine according to claim 1, characterized in that, The shut-off unit (10) includes a valve device (12) and a drive device (13) for driving the valve device (12).

3. The two-stroke internal combustion engine according to claim 2, characterized in that, The two-stroke internal combustion engine includes a control unit (11) configured to control an actuation device (18) for actuating the drive unit (13) to move the shut-off unit (10) according to the operating state of the two-stroke internal combustion engine (1).

4. The two-stroke internal combustion engine according to any one of claims 1 to 3, characterized in that, The closing unit (10) is configured to switch from the closed state of the second pipe (9) to the open state of the second pipe, or vice versa.

5. The two-stroke internal combustion engine according to claim 3, characterized in that, The control unit (11) is configured to command the shut-off unit (10) to open the second pipe (9) and, after a certain period of time, command the second pipe (9) to close.

6. The two-stroke internal combustion engine according to any one of claims 1 to 3, characterized in that, The shut-off unit (10) is configured to switch from a closed state at the inlet (8a) of the first pipe to a closed state at the inlet (9a) of the second pipe, or vice versa.

7. The two-stroke internal combustion engine according to claim 3, characterized in that, The control unit (11) is configured to command the shut-off unit (10) to close the inlet (8a) of the first pipe, and after a certain period of time, command the shut-off unit (10) to close the inlet (9a) of the second pipe.

8. The two-stroke internal combustion engine according to claim 2, characterized in that, The valve device (12) includes a plate (14) connected to a rotating member (15) which rotates about its own axis of rotation (15a); the rotating member (15) moves the plate (14) from a first position where it closes the inlet (8a) of the first pipe to a second position where it closes the inlet (9a) of the second pipe, or vice versa.

9. The two-stroke internal combustion engine according to claim 8, characterized in that, The first conduit (8) and the second conduit (9) each include abutting walls (16) for abutting against the disc-shaped plate (14).

10. The two-stroke internal combustion engine according to any one of claims 1 to 3, characterized in that, The first pipe (8) and the second pipe (9) each have a corresponding extension direction (D); the extension directions are converging or parallel to each other.

11. The two-stroke internal combustion engine according to any one of claims 1 to 3, characterized in that, The two-stroke internal combustion engine includes a pipe joint (17) that connects the exhaust port (5) of the combustion chamber (3) to the first pipe (8) and the second pipe (9).

12. The two-stroke internal combustion engine according to any one of claims 1 to 3, characterized in that, The first pipe (8) and the second pipe (9) branch off directly from the crankcase (2) and the shut-off unit (10) is integrated therein.

13. The two-stroke internal combustion engine according to claim 3, characterized in that, The actuation device (18) includes a coaxial motor.

14. A motorcycle, characterized in that, It includes a two-stroke internal combustion engine according to any one of claims 1 to 13.

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