FR2879673A1 - Internal combustion engine for motor vehicle, has closing system including flaps that are arranged and actuated to take finite number of preset stable positions, and are fabricated according to unique set of dimensions - Google Patents

Abstract

The engine has a cylinder head closing cylinders, where each cylinder is connected to a distributor by a swirl duct and a filling duct (4). A closing system for closing the duct (4) has two flaps (2, 3) adapted to take different positions in the duct (4) for varying air passage section. The flaps are arranged and actuated to take a finite number of preset stable positions. The flaps are fabricated according to unique set of dimensions. An independent claim is also included for a motor vehicle including an internal combustion engine.

Description

TECHNICAL FIELD TO WHICH THE INVENTION REFERS

  The present invention generally relates to internal combustion engines.

  It relates more particularly to an internal combustion engine comprising a distributor and a cylinder head closing cylinders. Each cylinder is connected to the distributor by at least two air intake ducts, namely a swirl duct and a filling duct. The engine also includes a shutter system of at least one of the air intake ducts. This shutter system has two flaps adapted to take different positions in the air intake duct to vary its air passage section.

  It also relates to a motor vehicle comprising such an internal combustion engine.

BACKGROUND

  The swirl generated by the swirl duct is a helical swirling motion of the intake gases in the cylinder of an engine, a swirling motion whose axis of rotation is parallel to the axis of the cylinder. This vortex homogenizes the intake gases, consisting of the mixture of air and fuel, in the cylinder. The magnitude to measure this vortex phenomenon is the number of swirls defined as the ratio between the speed of rotation of the intake gases and the engine speed.

  In addition, the permeability characterizes the ease with which the ducts pass the air.

  It is important to note that the number of swirls and the permeability vary inversely from one another. Indeed, for a given engine speed, an increase in the number of swirls implies a decrease in the permeability and vice versa.

  On internal combustion engines, the swirl is necessary at the time of the injection phase to ensure a correct mixture between fuel and oxidizer. It is therefore necessary to adapt the number of swirls to the power demand, or load, required by the user.

  For low loads, or power demands, the need for swirl is important to homogenize the mixture of air and fuel, while the need for permeability is low. On the other hand, at high loads the level of permeability is important. The mixture of air and fuel is easier and the level of swirl can be lowered.

  Nowadays, in order to ensure homogenization of the mixture between air and fuel, and sufficient permeability, it is known to implant a flap in one of the air intake ducts making it possible to increase the swirl by degrading the permeability, or, conversely, degrade the swirl by increasing the permeability.

  The shutter is operated by a motor between two extreme open and closed positions. The shutter can then travel continuously an infinite number of positions between the two extreme positions, including the latter.

  The swirl level then varies continuously between the extreme values of the positions of the flap corresponding to the open (free-flow) or closed (obstructed duct) positions.

  In theory, this technical solution makes it possible to reach all the values of number of swirls included between the extreme values. However, in practice, the positioning accuracy of the shutter is not very good and the swirl level is very dependent on the position taken by the shutter. This makes the sealing system difficult to develop and replicate in production. Finally, it is rarely necessary to have more than three different levels of swirl.

  OBJECT OF THE INVENTION In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes an internal combustion engine with an air intake duct closure system making it possible to obtain stable levels of swirl in finite number.

  For this purpose, it is proposed, according to the invention, an internal combustion engine as defined in the introduction, wherein it is provided that the flaps are arranged and actuated so as to take a finite number of predetermined stable positions.

  Thus, thanks to the invention, the flaps are positioned in a discrete manner in the duct in question and it is easy to adjust the level of swirl in the cylinders as a function of the closure of this intake duct. . In addition, the flap positioning configurations are reproducible, which allows to obtain determined and repeatable swirl levels as well.

  Advantageously, the flaps are adapted to take two predetermined stable positions. One of the stable positions of each flap is an open position parallel to the flow direction of the fluid, and the other of the stable positions is a closed position perpendicular to the flow direction of the fluid.

  According to a first embodiment of the internal combustion engine according to the invention, the two flaps are pivotally mounted on the same axis of rotation, the surfaces of the two flaps being superimposed and solid. According to this embodiment, the two flaps are of equal or different surfaces. In addition, when the two flaps are positioned in the direction of fluid flow, the larger surface flap is between the wall of the intake duct and the flap of smaller area.

  Thus, there are advantageously three different positioning configurations of different parts, so three levels of swirl well determined.

  According to a second embodiment of this internal combustion engine according to the invention, the two flaps are pivotally mounted on the same axis of rotation, the surfaces of the two flaps being superimposed. According to this embodiment the two flaps are of equal or different surfaces and one has a solid wall and the other has a recessed wall. In this case, in the closed position of the two flaps, the solid surface flap is superimposed on the flap whose surface has a recess for closing it. In the open position of the two flaps, the solid surface flap is between the wall of the duct and the shutter whose surface has a recess.

  Thus, we have three levels of swirl well determined. In addition, the recess being centered and of regular geometry, the flow of air circulation is more homogeneous.

  Finally, the manufacturing cost is reduced since it is sufficient to manufacture shutters in a single set of dimensions, then to evict some.

  According to a third embodiment of this internal combustion engine according to the invention, the two flaps are pivotally mounted on the same axis of rotation, the surfaces of the two flaps not being superimposed but juxtaposed or arranged side by side. In this case, the surfaces of the two flaps are solid or recessed. Depending on the number of swirl levels desired one can use flaps of equal or different surfaces.

  According to a fourth embodiment of this internal combustion engine according to the invention, the two flaps are pivotally mounted on different axes of rotation. According to this embodiment the axes of rotation of the flaps are parallel and contained in a plane extending along the cross section of the air intake duct. As before, it is possible to use flaps of equal or different surfaces and the two flaps are of solid surface.

  Thus, according to the third mode or the fourth embodiment, if the two flaps have equal surfaces, there are four flap positioning configurations, two identical, so three levels of swirl. On the other hand, if the two shutters have different surfaces, there are four different flap positioning configurations, thus four predetermined swirl levels.

  According to an alternative embodiment of the above-mentioned fourth embodiment, it is possible for the two flaps to have the same set of dimensions, but of the two flaps, one has a solid surface and the other has a recessed surface.

  Thus, as for the second embodiment of the invention, there are three levels of swirl well determined with a more homogeneous flow of air flow in the filling duct and a reduced flap manufacturing cost.

  In addition, according to the invention it is provided that: - the closure system can be located in the upstream portion of the air intake duct.

  - The shutter system is actuated by electrical or pneumatic means to two positions.

  The invention also relates to a motor vehicle which comprises an internal combustion engine as defined above.

  DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

  The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved.

  In the accompanying drawings: FIG. 1 is a view from above of the distributor of an internal combustion engine according to the invention, equipped with four pairs of air intake ducts, one of the two ducts of each pair comprising a system shutter shutters; FIG. 2 is a more detailed partial view of FIG. 1, showing a single cylinder connected to the distributor by its air intake ducts, the swirl duct and the filling duct; - Figure 3 is a side view of Figure 2 showing the shutter shutter system in the upstream portion of the filling duct; FIG. 4 is a perspective view of the filling duct of FIG. 3 cut longitudinally and equipped with a first embodiment of the shutter shutter system; FIG. 4A is a side view of FIG. 4; Figure 5 is a perspective view of the filling duct of Figure 3 cut longitudinally and equipped with a second embodiment of the shutter shutter system; FIG. 6 is a perspective view of the filling duct of FIG. 3 cut longitudinally and equipped with a third embodiment of the shutter shutter system; Figure 6A is a side view of Figure 6; Figure 7 is a perspective view of the filling duct of Figure 3 cut longitudinally and equipped with a fourth embodiment of the shutter shutter system; Figure 7A is a side view of Figure 7; Figure 8 is a perspective view of the filling duct of Figure 3 cut longitudinally and equipped with a fifth embodiment of the shutter shutter system; FIG. 8A is a side view of FIG. 8.

  Preliminarily, it will be noted that from one figure to another, the identical or similar elements of the different embodiments of the invention will, as far as possible, be referenced by the same reference signs and will not be described at each time. times.

  In the remainder of the text, the term solid or hollow surface of flaps means the solid or recessed wall of these flaps, and by equal or different surfaces of these flaps their projection in the cross section of the corresponding air intake duct.

  FIGS. 1 and 2 show schematically a part of an internal combustion engine 9 comprising a distributor 7 and a cylinder head 8 closing here four cylinders 6.

  Each cylinder 6 is connected to the distributor 7 by two air intake ducts 4,4A, namely a swirl duct 4A and a filling duct 4.

  The swirl duct 4A generates the swirl, that is to say the vortex of air at the intake in the cylinder 6. The filling duct 4 allows the good air filling of the cylinder 6.

  The swirl duct 4A generating the swirl makes it possible to homogenize the mixture of the air and the fuel by causing the gaseous mass to rotate in the cylinder 6 around the vertical axis of the latter. By reducing the passage section of the filling duct 4, the air flow becomes greater on the swirl duct 4A and the level of swirl increases. The different levels of swirl are then exploited during combustion depending on the operating point to limit pollutant emissions.

  In addition the internal combustion engine 9 shown comprises a shutter system 5 disposed in one of the air intake ducts 4, 4A.

  Here, as shown in Figure 2, there is provided a shutter system 5 upstream of each of the filling ducts 4, but of course we can provide that the shutter system 5 is placed in each swirl conduit 4A.

  Figure 3 shows that the closure system 5 placed in each filling duct 4 comprises two flaps 2.3 adapted to take different positions in the filling duct 4 to vary its air passage section.

  Advantageously, according to the invention, the flaps 2, 3 are arranged and actuated so as to take a finite number of predetermined stable positions.

  Preferably the shutters 2,3 are adapted to take two predetermined stable positions. One of said stable positions of each flap 2,3 is an open position 10,12 parallel to the flow direction of the fluid, and the other of said stable positions is a closed position 11,13 perpendicular to the flow direction of the fluid .

  In general, the shutter system 5 operates regardless of the flow direction A or B of the fluid (see FIGS. 4A, 6A, 7A, 8A).

  FIGS. 4 and 4A show a first embodiment of the invention according to which the two flaps 2, 3 are pivotally mounted around the same axis of rotation 1.

  To do this, the two flaps 2,3 are physically mounted on coaxial shafts which pivot independently of each other about the axis of rotation 1. The pivoting shafts are actuated by a two-position electric or pneumatic actuator .

  According to this embodiment, the surfaces of the two flaps 2, 3 are solid and superimposed. The surface S2 of the shutter 3 is greater than the surface S1 of the shutter 2. When the two shutters 2, 3 are open, positioned parallel to the direction of flow of the fluid, the shutter 3 of larger surface S 2 is between the wall filling duct 4 and flap 2 of smaller area S1.

  The shut-off system 5 shown in FIGS. 4 and 4A operates in the following manner: In order for the filling duct 4 to be free flowing, the electric or pneumatic actuator rotates the shafts of the shutters 2,3 to position those in their open position 10,12 stable, parallel to the flow of the fluid.

  To reduce the flow of the fluid in the filling duct 4, a portion of the surface of the cross-section of said filling duct 4 is obstructed. The actuator rotates the shaft on which the flap 2 is positioned to position it according to its closed position 11, its other stable position, perpendicular to the flow of the fluid in the filling duct 4.

  Thus the shutter 2 in the closed position 11 closes the surface S1 of the straight section of the duct 4.

  To further reduce the flow of the fluid in the filling duct 4, a greater part of the surface of the cross-section of said filling duct 4 is closed. In the same way as for the closing of the shutter 2, the actuator position the flap 3 according to its closed position 13 stable.

  Thus, the flap 3 of larger area S2 closes superimposed on flap 2 of lesser surface S1 already closed, to seal all or part of the remaining surface of the cross section of said duct 4.

  Note that the flap 2 of lesser area S1 can not be in the open position when the flap 3 of larger area S2 is closed. It is first necessary to operate the shutter 3 in the open position 12, then the shutter 2.

  The filling duct 4 may be: -Free flowing, with the flap 2 in the open position 10 and the flap 3 in the open position 12.

  -In first closed position, with the shutter 2 in the closed position 11 and the shutter 3 in the open position 12.

  -In second closed position, with the shutter 2 in the closed position 11 and the shutter 3 in the closed position 13.

  Thus, according to this first embodiment, three flap positioning configurations 2,3 corresponding to three levels of swirl.

  FIG. 5 shows an alternative embodiment of the invention according to which the surfaces S1 and S2 of the two flaps 2, 3 are not superimposed but juxtaposed or aligned on the same axis of rotation 1. pivots independently of each other as for the embodiment previously described.

  In addition, each flap 2,3 can be positioned in closed or open position regardless of the position of the other flap.

  In the closed position, each shutter 2.3 closes part of the straight section of the filling duct 4. Thus, with two shutters 2,3 of different surfaces S1 and S2, four shutter levels of said corresponding filling duct 4 are available. four-level swirl.

  Figures 7 and 7A show another alternative embodiment of the first embodiment shown in Figures 4 and 4A. According to this variant the flaps 2,3 are superimposed on the same axis of rotation, but the surface S2 of the flap 3 is full while the surface S1 of the other flap 2 has a recess 2A surface SO. Here the recess 2A is circular but it could be of a very different form.

  In the closed position 11,13 of the two shutters 2,3, the solid shutter 3 is superimposed on the hollow flap 2 to close the recess 2A surface SO.

  In the open position 10,12 of the two shutters 2,3, the solid shutter 3 is between the wall of the filling duct 4 and the recessed flap 2.

  There are thus three filling levels of the filling duct as in the first embodiment, and therefore three levels of swirl.

  In addition, compared to the first embodiment, the manufacturing cost of the shutters 2,3 is decreased and the air flow in the filling duct 4 is more homogeneous.

  FIGS. 6 and 6A show a fourth embodiment of the invention according to which the two flaps 2, 3 are pivotally mounted on different axes of rotation 1A, 1B. These axes of rotation 1A, 1B are parallel and are contained in a plane extending along the cross-section of the filling duct 4.

  The surfaces S1 and S2 of the flaps 2,3 are solid and identical. The two shutters 2,3 are mounted on independent parallel shafts, actuated in rotation by an electric or pneumatic actuator to position said shutters 2,3 in the closed position 11,13 (perpendicular to the flow of the fluid in the filling duct 4 ) or open 10, 12 (parallel to the flow of fluid in the filling duct 4).

  The shutter system 5 shown in FIGS. 6 and 6A operates in the following manner: In the open position 10, 12, each flap 2.3 extends against the inside wall of the air intake duct 4 so as to leave free substantially the entire passage section of said duct 4.

  To close this cross-section, the shutter 2 is positioned in the closed position 11 so as to close off the surface S1 of the straight section of the duct, then the flap 3 is positioned in the closed position 13 to close off all or part of the remaining surface of the straight section of said duct. There are three levels of swirl here too.

  Figures 8 and 8A show an alternative embodiment of the invention shown in Figures 6 and 6A according to which the surface of the flap 3 is full while the surface of the other flap 2 has a recess 2A surface S0.

  Again the recess 2A is circular but it could be of a different shape. However, it is advantageous to have a recess 2A of regular contour to have a homogeneous air flow in the filling duct 4.

  Here we also have three levels of shutter so three levels of swirl corresponding to closed positions combined 11,13 and open 10.12 shutters 2,3.

  Advantageously, thanks to the invention described above, one obtains stable and predetermined shutter levels of each of the filling ducts 4 which allows to obtain stable and predetermined swirl levels.

  The present invention is not limited to the embodiments described and shown, but the skilled person will be able to make any variant within his mind.

Claims (23)

  An internal combustion engine (9) comprising a distributor (7), a cylinder head (8) enclosing cylinders (6), each cylinder (6) being connected to said distributor (7) by at least two intake ducts. air (4,4A), namely a swirl duct (4A) and a filling duct (4), and a closure system (5) of at least one of said air ducts comprising two flaps ( 2,3) adapted to take different positions in said air intake duct (4,4A) to vary its air passage section, characterized in that the flaps (2,3) are arranged and actuated by to take a finite number of predetermined stable positions.   2. Internal combustion engine (9) according to claim 1, characterized in that said flaps (2,3) are adapted to take two predetermined stable positions (10,11,12,13).   3. Internal combustion engine (9) according to claim 2, characterized in that one of said stable positions of each flap (2,3) is an open position (10,12) parallel to the flow direction of the fluid, and the other of said stable positions is a closed position (11, 13) perpendicular to the flow direction of the fluid.   4. Internal combustion engine (9) according to one of claims 1 to 3, characterized in that the two flaps (2,3) are pivotally mounted on the same axis of rotation 1.   5. Internal combustion engine (9) according to claim 4, characterized in that the two flaps (2,3) are of different surfaces.   6. Internal combustion engine (9) according to claim 4, characterized in that the two flaps (2,3) are of equal areas.   7. Internal combustion engine (9) according to one of claims 4 to 6, characterized in that the surfaces of the two flaps (2,3) are solid.   8. Internal combustion engine (9) according to one of claims 4 to 6, characterized in that the surface of one of the shutters (3) is full while the other (2) has a recess (2A).   9. Internal combustion engine (9) according to one of claims 4 to 8, characterized in that the surfaces of the two flaps (2,3) are superimposed.   10. Internal combustion engine (9) according to claims 7 and 9, characterized in that when the two flaps (2,3) are positioned parallel to the direction of flow of the fluid, the flap (3) of larger area is between the wall of the air intake duct (4, 4A) and the shutter (2) of smaller area.   11. Internal combustion engine (9) according to claims 8 and 9, characterized in that in the closed position (11,13) of the two flaps (2,3), the flap (3) of solid surface is superimposed on the shutter (2) whose surface has a recess (2A) for closing it.   12. Internal combustion engine (9) according to one of claims 8 and 9 or 11, characterized in that in the open position (10, 12) of the two flaps (2,3), the flap (3) surface solid is between the wall of the duct and the flap (2) whose surface comprises a recess.   13. Internal combustion engine (9) according to one of claims 4 to 8, characterized in that the surfaces of the two flaps (2,3) are juxtaposed.   14. Internal combustion engine (9) according to one of claims 1 to 3, characterized in that the two flaps (2,3) are pivotally mounted on different axes of rotation (1A, 1B).   15. Internal combustion engine (9) according to claim 14, characterized in that the axes (IA, 1B) of rotation of the flaps (2, 3) are parallel and contained in a plane extending along the straight section of the duct. air intake (4,4A).   16. Internal combustion engine (9) according to one of claims 14 or 15, characterized in that the surfaces of the two flaps (2,3) are solid.   17. Internal combustion engine (9) according to one of claims 14 or 15, characterized in that the surface of one of the flaps (2,3) is full while the other has a recess.   18. Internal combustion engine (9) according to one of claims 16 or 17, characterized in that the two flaps (2,3) have different surfaces.   19. Internal combustion engine (9) according to one of claims 16 or 17, characterized in that the two flaps (2,3) have equal surfaces.   20. Internal combustion engine (9) according to one of claims 17 to 19, characterized in that in the closed position (11,13) for the two flaps (2,3), the flap (3) of solid surface is superimposed on the flap (2) whose surface has a recess (2A) to seal it.   21. Internal combustion engine (9) according to any one of claims 1 to 20, characterized in that said closure system (5) is located in the upstream portion of said intake duct (4,4A).   22. Internal combustion engine (9) according to any one of claims 1 to 21, characterized in that the shutter system (5) is actuated by a two-position electric or pneumatic actuator.   23. Motor vehicle which includes an internal combustion engine (9)   according to any one of claims 1 to 22.