Improved intake system for internal combustion engine, internal combustion engine and motor vehicle

Abstract

The intake system of an internal combustion engine (8) comprises an air transport duct extending from an air inlet opening to an air discharge opening and defining a transport volume, and "n" intake trumpets spaced apart from one another and facing the air discharge openings, "n" being greater than or equal to 2. Preferably, the transport duct comprises at least one internal partition dividing the duct internally along its extension from the air inlet opening to the air discharge opening into "n" ducts fluidly separated from one another, each of the "n" ducts facing a corresponding intake trumpet at the air discharge opening. [Selected Figure] Figure 1

Description

[Technical field]

[0001] The present invention relates to an improved air intake system for an internal combustion engine, an internal combustion engine equipped with such an air intake system, and a motor vehicle equipped with such an air intake system. [Background technology]

[0002] As is well known, multi-cylinder internal combustion engines have problems with cylinder filling efficiency, which significantly reduces volumetric efficiency.

[0003] In essence, the intake system typically has a box (called an airbox) that collects the intake air and routes it to the individual intake ducts of the cylinders (trumpets). The intake flow dynamics are very complex because the cylinders do not operate as in phase as possible to control the torque output and therefore the engine operation. That is, the combustion cycles of the individual cylinders (whether Diesel or Otto) are out of phase.

[0004] Thus, during the intake phase of one cylinder the combustion phase of another cylinder may occur, and so on.

[0005] The intake cycles of the various cylinders can interfere with each other, reducing the overall volumetric efficiency of the engine just inside the filter box.

[0006] Furthermore, the operating range, i.e. the speed range, of an internal combustion engine can vary considerably, giving rise to intake air mass resonance phenomena which can improve or worsen the overall volumetric efficiency at certain speeds.

[0007] These phenomena are even more difficult to deal with in the case of engines which have a very wide speed range, such as those used in motorcycles.

[0008] To improve the intake flow dynamics, several solutions have been considered that essentially modify the length of the intake duct depending on the engine speed, thus trying to take advantage of the resonance phenomenon to help fill the cylinders.

[0009] These solutions fail to optimize engine operation because they do not take into account the specific operating characteristics of each cylinder, which are primarily (but not exclusively) due to the engine architecture itself, i.e., the placement of the cylinders relative to the airbox. Summary of the Invention

[0010] Thus, a need is felt to overcome the deficiencies and limitations noted with respect to the known art.

[0011] Such requirements are met by the internal combustion engine intake system according to claim 1, 18 and by the internal combustion engine according to claim 19 This is satisfied by the motor vehicle described in . [Brief description of the drawings]

[0012] Further features and advantages of the present invention will become more apparent from the following description of preferred, non-limiting examples of embodiments of the invention.

[0013] [Figure 1] FIG. 1 shows an expanded schematic diagram of an internal combustion system according to an embodiment of the present invention.

[0014] Elements or parts of elements common to the embodiments described below are designated by the same reference numerals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Referring to the aforementioned drawings, an assembled schematic diagram of an intake system for an internal combustion engine 8 according to the present invention is shown generally at 4.

[0016] For purposes of the present invention, the term "internal combustion engine" should be considered broadly and includes any engine type or architecture, including not only the Otto cycle and Diesel cycle endothermic engines of the above categories, but also rotary engines (Wankel).

[0017] Furthermore, the engine type has no bearing on the type of vehicle in which it may be installed.

[0018] As mentioned above, the invention is of particular benefit to motorcycles, which are characterized by significant constraints regarding size, weight and aesthetics, but it is equally applicable to automobiles, industrial vehicles and motor vehicles in general.

[0019] The term "motorcycle" means a motorized bicycle with at least two wheels (i.e., front and rear wheels). This definition therefore also includes motorcycles with three wheels, for example with two paired steering wheels on the front carriage and one driving wheel on the rear axle, and motorcycles also include a single steering wheel on the front carriage and two driving wheels on the rear axle. Finally, four-wheeled vehicles (quadricycles) are also included in the definition of a motorcycle, with quadricycles having two wheels on the front carriage and two wheels at the rear.

[0020] The intake system 4 for an internal combustion engine 8 comprises an air transport duct 12 which defines a transport volume, extending from an air intake opening 16 to an air discharge opening 20 .

[0021] Typically, upstream of the air inlet opening 16, the air intake system 4 comprises at least one air filter 24. The air filter 24 may also be arranged in the air transport duct 12 or even downstream of the air exhaust opening 20. In either case, the air filter 24 may also be omitted.

[0022] The intake system 4 further comprises "n" intake trumpets 28. The intake trumpets 28 are spaced apart from each other and face the air discharge opening 20. "n" is 2 or greater.

[0023] The intake trumpets 28 preferably have a frusto-conical shape tapering in a known manner from the air discharge opening 20 towards the associated cylinder of the internal combustion engine 8, i.e. the trumpets have a smaller diameter opening facing the respective cylinder. Preferably, each intake trumpet 28 is associated with a corresponding cylinder of the internal combustion engine 8 to supply the same. As is evident, the number "n" of intake trumpets 28 and the number of cylinders of the internal combustion engine 8 are equal to or greater than two. This means that the intake system 4 of the present invention can be applied to any internal combustion engine 8 of the multi-cylinder type.

[0024] Preferably, the air transport duct 12 includes at least one partition 32 extending continuously along the air transport duct 12 and dividing the interior of the air transport duct 12 into "n" mutually fluidly isolated channels 36.

[0025] That is, the internal partition 32 preferably extends along the entire area between the air inlet opening 16 and the air outlet opening 20. In this way, the "n" channels 36 do not communicate with each other in the air transport duct 12 and do not influence each other. The air and / or pressure wave exchange between the "n" channels may take place upstream of the air inlet opening 16 and / or downstream of the air outlet opening 20, where each of the "n" channels 36 eventually faces a corresponding intake trumpet 28.

[0026] Specifically, as described in more detail below, air / wave pressure exchange between the "n" ducts downstream of the air exhaust openings 20 homogenizes the intake flow at the individual cylinders and optimizes the overall volumetric efficiency of the internal combustion engine 8.

[0027] According to one embodiment, the “n” channels 36 are defined by at least one interior partition 32 and by the inside, i.e., inner wall, of the air transport duct 12 .

[0028] As will be apparent, at least one internal partition 32 preferably divides the transport volume into “n” volumes of channels 36 .

[0029] The internal combustion engine 8 preferably comprises a number "n" of cylinders, equal to the number "n" of channels. Each cylinder is provided with a respective intake trumpet 28 and is fluidly supplied by a respective channel 36.

[0030] According to one embodiment, the intake system 4 comprises an air box 30 arranged to include at least a part of the intake trumpet 28, at least a part of the air transport duct 12 and its bulkhead 32, such that the air inlet opening 16 is located outside the same air box 30. Essentially, the air box 30 has a box shape merging with an air exhaust opening 20, i.e. an air outlet 20. Such an outlet 20 faces a large diameter mouth 40 of the trumpet 28.

[0031] According to one embodiment, the air transport duct 12 and the at least one internal partition 32 are formed such that a gap 44 is defined between the air discharge opening 20 of the channel 36 and the corresponding intake edge 40 of the intake trumpet 28 .

[0032] An air inlet lip 40 defines an intake area or mouth on the inside of each intake trumpet 28 for the airflow coming from the corresponding channel 36 facing each intake trumpet 28 .

[0033] The intake trumpet 28 preferably has a generally tapered shape, for example a frusto-conical shape, varying from the side of the air discharge opening 20 towards the corresponding intake duct of the internal combustion engine 8 .

[0034] The overall taper shape need not have a circular cross section with respect to a cross-sectional plane perpendicular to the main axis of extension of the intake trumpet 28. It may also have a different kind of cross section, including, for example, an elliptical type shape.

[0035] Additionally, it is also possible to provide the intake trumpet 28 with a shape that has a substantially constant cross-section, ie, with substantially no tapered portions.

[0036] According to the envisaged embodiment, the gap 44 has a width comprised between 30% and 70% of the diameter 48 of the air inlet edge 40 of the corresponding inlet trumpet 28. The diameter 48 must be understood in relation to a cross-sectional plane perpendicular to the main extension axis of the inlet trumpet 28. In particular, the gap 44 is measured in height relative to the inlet mouth of the trumpet or relative to the inlet edge of the trumpet. The gap 44 can also be determined radially, i.e. as the difference in diameter between the mouth of the respective transport duct and the mouth of the corresponding trumpet.

[0037] According to a contemplated embodiment, the intake trumpet 28 is coupled with a moving means, not shown, configured to vary the gap 44 in an appropriate manner.

[0038] The variation of the clearance 44 is preferably achieved in response to changes in the operating parameters of the internal combustion engine 8. Typically, the variation of the clearance 44 varies with the speed of the internal combustion engine 8 in order to optimize the volumetric filling of individual cylinders of the same engine by utilizing the phenomenon of resonance of the intake airflow.

[0039] For example, the moving means is configured to move the air intake edge 40 into contact with the air discharge opening 20, substantially eliminating the gap 44. And by eliminating, we mean the achievement of a few millimeters or a few tenths of a millimeter, thereby substantially excluding external dispersion in the passage of the air flow. When the gap 44 is eliminated, the air intake flows of the adjacent channels 36 are prevented from influencing each other even after they have flowed out of the air discharge opening 20. The gap 44 may be substantially eliminated, for example, by moving the air intake edge 40 of the intake trumpet 28 into contact with a portion of each corresponding channel 36 at the air discharge opening 20. The contact between the components is preferably weakened by the presence of at least one intervening gasket, which allows the air flow to be sealed in addition to reducing vibration and noise.

[0040] The moving means may also be configured to move the intake edge 40 at least partially into the channel 36 so as to eliminate the gap 44 .

[0041] According to a contemplated embodiment, the movement of the intake trumpets 28 is independent to vary the "n" gaps independently.

[0042] That is, it is possible to vary the distance between each intake trumpet 28 and the corresponding channel 36 independently and separately. In this way, it is possible to optimize the volumetric filling of each cylinder depending on the specific and fortuitous operating conditions of the same cylinder, for example related to the architecture and the position of the ducts in the intake system 4, and taking into account parameters of a geometric nature. For example, in an engine with a "V" configuration, it is possible to increase or decrease the gap 44 of the cylinder located on the side facing forward and, conversely, to decrease or increase the gap 44 of the corresponding cylinder located on the opposite side.

[0043] According to a contemplated embodiment, at least one internal partition 32 divides the transport volume into "n" volumes of channels 36, which are substantially identical to one another.

[0044] For example, it is possible for the air passage area of ​​channels 36 having a small extension length to be large and the air passage area of ​​channels having a large extension length to be small. The extension length is the average length traveled within each channel 36 to pass from the air intake opening 16 to the air exhaust opening 20.

[0045] According to a contemplated embodiment, the at least one internal partition 32 is provided with at least one moving member (not shown) coupled to a motor means (not shown) capable of changing the volume of at least one of the "n" channels 36.

[0046] The arrangement of the channels 36 can vary widely and is typically, but not exclusively, based on the architecture of the internal combustion engine 8, i.e., the arrangement of the associated cylinders.

[0047] For example, at least two of the channels 36 may be provided arranged side by side in a transverse direction T perpendicular to the direction X of air flow through the air inlet opening 16, ie the inlet direction.

[0048] It is also possible to provide at least two of the channels 36 arranged side by side and in a longitudinal direction L perpendicular to the direction of air flow through the air inlet opening, ie the incoming direction.

[0049] For example (FIG. 1), the air transport duct 12 may be provided with four channels 36 arranged along the transverse direction T and the longitudinal direction L in a square matrix arrangement.

[0050] The channels 36 may be provided to carry only intake air or a mixture of air and fuel suitably injected by the fuel injectors 52 .

[0051] According to one embodiment, each of the “n” channels may at least partially house a fuel injector 52 .

[0052] In the present invention, the particular type of fuel injector 52, which may be electronic, piezoelectric, or the like, is not relevant.

[0053] A fuel injection point P of the fuel injector 52 is preferably located within each channel 36 at a distance D from the air discharge opening 20 that is greater than or equal to 20% of the cross-sectional diameter K of the channel 36 at the air discharge opening 20 .

[0054] According to a contemplated embodiment, each fuel injector 52 extends through at least one channel 36 .

[0055] For example, if the channels 36 are at least partially overlapping, for example, along the longitudinal direction L, then each fuel injector may pass through at least two channels 36, also overlapping along the same longitudinal direction L.

[0056] The fuel injectors 52 may be positioned and better oriented in a variety of ways within each channel 36, with the fuel injectors 52 being oriented substantially perpendicular to the air exhaust openings 20 of each channel 36 in some contemplated embodiments.

[0057] As can be seen from the above, the present invention overcomes the shortcomings of the prior art.

[0058] Specifically, by subdividing the duct into "n" channels over the entire length of the same duct (i.e., from the air intake opening to the air exhaust opening), each channel can be calibrated according to the particular intake trumpet (and associated cylinder) that supplies it, without allowing the individual intake flows to affect each other, unless air leaks out of the exhaust opening.

[0059] The presence of the gap therefore makes it possible to obtain pressure exchange at the intake edges of adjacent trumpets, "homogenising" the intake flow in the various cylinders and optimising the overall volumetric efficiency.

[0060] Due to the division between the individual ducts, the premixing of air and fuel inside each of the ducts, in the entire area between the air intake opening and the air discharge opening, is not influenced by the adjacent ducts.

[0061] The homogenization and recovery of the intake air into the trumpet is influenced and optimized by the resonances of the various ducts only after it has passed through the air exhaust openings.

[0062] Also, if necessary, gaps may be blocked to avoid interference between at least one duct and an adjacent duct under certain operating conditions.

[0063] The placement of the injectors in fluidly separated ducts allows for better separation of the spray and very precise control of the mixture and titer of gas delivered by each trumpet to each cylinder.

[0064] Those skilled in the art may make numerous modifications and variations to the above-described intake system and engine to meet foreseen and particular requirements, all of which are within the scope of the present invention as defined by the following claims.

Claims

1. an air transport duct (12) extending from an air intake opening (16) to an air exhaust opening (20) and defining a transport volume; 1. An intake system (4) for an internal combustion engine (8), comprising: "n" intake trumpets (28) spaced apart from one another and facing said air discharge opening (20), "n" being 2 or greater, said air transport duct (12) comprises at least one internal partition (32) dividing said air transport duct (12) internally along its extent into "n" channels (36) fluidly separated from one another, said "n" channels (36) facing corresponding intake trumpets (28) at said air discharge openings (20); the air transport duct (12) and the at least one internal partition (32) are arranged such that a gap (44) is provided between the air discharge opening (20) of the channel (36) and the air intake edge (40) of the corresponding intake trumpet (28); The at least one internal partition (32) extends along the entire distance between the air intake opening (16) and the air exhaust opening (20). An intake system (4) for an internal combustion engine (8).

2. 2. An intake system (4) for an internal combustion engine (8) as claimed in claim 1, wherein said "n" channels (36) are bounded by said at least one internal partition (32) and by the inside of said air transport duct (12).

3. The intake system (4) for an internal combustion engine (8) according to claim 1 or claim 2, wherein the at least one internal partition (32) divides the transport volume into "n" volumes of the channel (36), in particular the "n" volumes of the channel (36) being substantially equal to one another.

4. 4. An intake system (4) for an internal combustion engine (8) as claimed in any one of claims 1 to 3, wherein the gap (44) has a width comprised between 30% and 70% of a diameter (48) of the air intake edge (40) of the corresponding intake trumpet (28).

5. 5. An intake system (4) for an internal combustion engine (8) as claimed in any one of claims 1 to 4, wherein the intake trumpet (28) is connected to a moving means configured to vary the gap (44).

6. 6. An intake system (4) for an internal combustion engine (8) as set forth in claim 5, wherein movement of the intake trumpets (28) is independent to individually vary the "n" gaps (44).

7. 7. The air intake system (4) for an internal combustion engine (8) according to claim 6, wherein the moving means is configured to move the air intake edge (40) into contact with the air discharge opening (20) and eliminate the gap (44).

8. 8. An intake system (4) for an internal combustion engine (8) as claimed in claim 6 or claim 7, wherein the moving means is configured to move the air inlet edge (40) at least partially into the channel (36) and eliminate the gap (44).

9. The intake system (4) for an internal combustion engine (8) according to any one of claims 1 to 8, wherein the at least one internal partition (32) comprises at least one movable member connected to a motor means configured to vary the volume of at least one of the "n" channels (36).

10. 10. An intake system (4) for an internal combustion engine (8) as claimed in any one of claims 1 to 9, wherein at least two of the channels (36) are aligned in a transverse direction (T) perpendicular to the direction of air flow at the air intake opening (16).

11. 11. The air intake system (4) for an internal combustion engine (8) according to claim 10, wherein at least two of the channels (36) are aligned in a longitudinal direction (L) perpendicular to the transverse direction (T) and to the direction of air flow at the air intake opening (16).

12. 12. An intake system (4) for an internal combustion engine (8) according to claim 11, comprising four channels (36) arranged according to a square matrix pattern along said transverse direction (T) and said longitudinal direction (L).

13. 13. An intake system (4) for an internal combustion engine (8) as claimed in any one of claims 1 to 12, wherein a fuel injector (52) is housed, at least in part, inside each of the "n" channels (36).

14. 14. An intake system (4) for an internal combustion engine (8) as claimed in claim 13, wherein each fuel injector (52) passes through at least one channel (36).

15. 15. An intake system (4) for an internal combustion engine (8) according to claim 13 or claim 14, wherein the fuel injectors (52) are oriented substantially perpendicular to the air discharge openings (20) of each channel (36).

16. 16. An air intake system (4) for an internal combustion engine (8) according to any one of claims 1 to 15, wherein the air intake system (4) comprises at least one air filter (24) arranged upstream of the air intake opening (16).

17. 17. The intake system (4) for an internal combustion engine (8) according to any one of claims 1 to 16, comprising an airbox (30) arranged to include at least a portion of the intake trumpet (28), at least a portion of the air transport duct (12) and its partition (32) such that the air intake opening (16) is located outside the airbox (30).

18. 18. An internal combustion engine (8) comprising an intake system (4) according to any one of claims 1 to 17, said internal combustion engine (8) comprising a number "n" of cylinders equal to the number "n" of channels (36), each cylinder having a respective intake trumpet (28) and supplied by a respective channel (36).

19. A motor vehicle comprising an intake system (4) according to any one of claims 1 to 17 and / or an internal combustion engine (8) according to claim 18.

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