FR2743111A1 - Motor vehicle I.C. engine inlet - Google Patents

Abstract

The intake consists of first and second inlet ducts (5, 6) inside the cylinder head (3) for each combustion chamber (4), connected to an inlet manifold tube (9). A controlled shutter (10) between the ducts and the tube to open or close the second inlet duct selectively according to the engine's operating mode. The shutter comprises a rotor (12) in a seat (11) with a cylindrical recess, set in a housing (10) between the cylinder head and inlet manifold (7) which has two passages leading to the two ducts. The shutter is in the form of a plug with a transverse aperture in one side, rotated by a rack and pinion (13, 14) actuated pneumatically in response to variations in the engine load.

Description

INTAKE DEVICE FOR A MOTOR
INTERNAL COMBUSTION
The present invention relates to an intake device for an internal combustion engine intended in particular to equip a motor vehicle. The device targeted by the invention more specifically controls an intake device of an internal combustion engine of the type comprising two intake circuits per cylinder and shutter means capable of selectively opening or closing one of the two circuits. according to the engine operating conditions.

 It is well known, in particular from document FR-A-92-06.863, to improve the efficiency of an engine by promoting a high level of turbulence in the combustion chambers under predetermined operating conditions of the engine such as low loads, without however degrading too much the filling of the combustion chambers during high load operations.

 For this purpose, numerous arrangements have been proposed according to which each cylinder is supplied with air or a fuel mixture (depending on whether the injection of fuel is carried out directly or not into the combustion chamber) by two intake ducts. separate, each of these conduits opening respectively into the combustion chamber through an orifice which is conventionally closed by a valve with a stem valve.

 The first duct is then shaped to cause a vortex movement of the intake gases, while the second substantially straight duct cooperates with a butterfly-type shutter which makes it possible to control the flow of gases in this duct and in particular of the interrupt more or less completely depending on the engine operating conditions so that the flow of gases emerging through this conduit into the combustion chamber does not interfere with the swirling movement of the gases coming from the first conduit.

 The use of a butterfly-type rotary shutter formed by a disc secured to a drive shaft controlled in rotation to seal the second duct has the drawback, however, of generating significant pressure drops in this second duct. as well as in the first duct when the drive axis of the flaps extends parallel to the line of the cylinders crossing the latter, these pressure drops having the effect of limiting the filling of the engine and affecting engine performance.

 In order to remedy this drawback, the subject of the invention is a device for controlling the supply of a combustion engine of the type comprising at least two intake ducts per cylinder, adapted to selectively open or close one ducts without generating pressure losses and which is simple in construction and therefore robust and inexpensive.

 The intake device for an internal combustion engine according to the invention is of the type comprising for each combustion chamber at least a first and a second intake ducts formed inside a cylinder head, at least one manifold an intake manifold extending said intake ducts outside the cylinder head and piloted shutter means interposed between the intake ducts and the tubing for selectively opening or closing said second intake duct in response to operating conditions of the motor.

 According to the invention, the intake device for an internal combustion engine is characterized in that the shutter means comprise a closing element sliding along a seat, this closing element being pivotally mounted and having at least one face d filling in the form of a solid surface of revolution.

 According to another characteristic of the intake device for internal combustion engine object of the invention, the first intake duct is shaped to cause a swirling movement of the intake gases and in that the second intake duct is shaped to favor the filling of the combustion chamber.

 According to another characteristic of the intake device for an internal combustion engine which is the subject of the invention, the seat of the closing element is constituted by the internal walls of a corresponding cylindrical housing formed in a body, this body being interposed between the cylinder head and the intake manifold and comprising a first and a second passage intended respectively to be connected by their outlet orifices with the inlet orifices of the first and second intake ducts and by their inlet orifices with the manifold of the manifold of admission.

 According to another characteristic of the intake device for internal combustion engine object of the invention, the housing of the closure element opens through the second passage in a direction substantially perpendicular to the axis of the second passage.

 According to another characteristic of the intake device for an internal combustion engine which is the subject of the invention, the closure element consists of a plug of dimensions corresponding substantially to those of its housing, this plug having a transverse opening opening laterally.

 According to another characteristic of the intake device for an internal combustion engine object of the invention, the inlet openings of the first and second passages formed through the body open into a common passage, this common passage being connected by its orifice d entry to the outlet of the corresponding tubing of the intake manifold and in that the plug housing is positioned in line with the connection zone between the second passage and the common passage.

 According to another characteristic of the intake device for an internal combustion engine which is the subject of the invention, the closing element is rotated by controlled maneuvering and immobilizing means comprising a pinion, a rack and a controlled pneumatic actuator from the engine load.

The aims, aspects and advantages of the present invention will be better understood from the description presented below of an embodiment of the intake device for an internal combustion engine according to the invention, given by way of example. not limiting, with reference to the accompanying drawings, in which
Figure 1 is a partial schematic view, in section along a plane extending transversely relative to the longitudinal axis of the engine, showing an intake device according to the invention in a first operating position
Figure 2 is a partial schematic view, in section along the line II-II of Figure 1, showing the intake device in the first operating position
Figure 3 is a view similar to Figure 2 showing the intake device in a second operating position
Figure 4 is a detail view, in perspective, of the plug used on the intake device according to the invention.

 Only the elements necessary and sufficient for understanding the invention have been shown in the drawings. Furthermore, to facilitate reading of these drawings, the same references are used to designate the same parts from one figure to another.

 In accordance with FIG. 1, the intake device shown is more particularly intended for supplying an internal combustion engine of the multicylinder type (with spark ignition or with compression ignition).

 Only the part of the intake device serving a combustion chamber referenced 4 has been shown, the device repeating itself substantially identically opposite the other combustion chambers of the engine.

 The internal combustion engine which in the example illustrated is a four-cylinder in line, conventionally comprises a cylinder block, not shown, comprising four aligned cylindrical bores. This cylinder block is surmounted by a cylinder head 3.

 The cylinder head 3 has on its lower face combustion chambers 4 each intended to cover a corresponding cylindrical bore. The cylinder head 3 also has intake and exhaust ducts respectively serving to bring the intake gases (fuel mixture or fresh air depending on whether the engine is indirect injection or direct injection) and to evacuate the burnt gases.

 Each of the combustion chambers 4 of the cylinder head 3 is supplied in a manner known per se by a first and a second separate intake ducts which extend substantially parallel to one another. The first intake duct 5 is, in the illustrated example, shaped to cause a vortex movement of the intake gases (for example of the "swirl" type: the axis of rotation of the gases then being parallel to the axis of the cylinder) when entering the combustion chamber 4. The second intake duct 6 is in turn, in the example shown, shaped to have the least pressure drop possible and promote filling.

 Each of the intake conduits 5 and 6 formed through the cylinder head 3 extends from an inlet gas inlet port formed in a side face 30 of the cylinder head 3, to an outlet port opening into the combustion chamber 4, this outlet orifice forming the seat of a stem valve whose opening is controlled by an appropriate cam carried by a camshaft not shown.

 These first and second intake ducts 5 and 6 are extended outside the cylinder head by a single corresponding tubular duct 9 of an intake manifold 7 whose distribution chamber or plenum 8 extends substantially above of the cylinder head 3.

 A controlled shutter device 10 is interposed between the intake conduits 5 and 6 formed in the cylinder head 3 and the corresponding tubing 9 of the intake manifold 7. The purpose of this controlled shutter device 10 is to open or close, depending on the engine operating conditions, the supply of fresh air or a fuel mixture to the combustion chamber 4 through the second straight intake duct 6.

 The shutter device 10 comprises according to the invention a body 18 which extends parallel to the cylinder head 3. This body 18 has two substantially planar faces 20 and 21, a first face 20 intended to rest in a sealed manner on the lateral face 30 of the cylinder head 3 where the inlet openings of the intake conduits 5 and 6 open out and a second face 21 intended to receive in leaktight manner the pipes 9 of the intake manifold 7. Immobilization of the body 10 on the cylinder head 3 and tubing 9 on the body 10 is preferably operated by means of suitable flanges.

 The body 18 has first and second interior passages respectively 15 and 16 opening on the first face 20 by outlet orifices intended to be positioned respectively opposite the inlet orifices of the intake conduits 5 and 6 opening on the lateral face 30 of the cylinder head 3.

 These interior passages open at their upstream ends, in the direction of flow of the intake gases, into a common connection passage 19, extending in their extension and which opens on the face 21 of the body 10 through an orifice d inlet intended to be positioned opposite the outlet orifice of the pipe 9 of the intake manifold 7.

 In line with the connection zone between the second passage 16 and the common passage 19, the body 18 has a blind cylindrical housing 11 extending perpendicular to these passages and substantially transversely relative to the longitudinal axis of the engine. The interior walls of this housing 11 form the seat of a rotary closure element or plug 12. Non-illustrated sealing means ensure the sealed mounting of the plug 12 in its housing 11.

 The plug 12 is rotated by maneuvering means 17 so as to selectively close or open the inlet of the second passage 16 by sliding along its seat in a direction substantially perpendicular to the axis of the second passage 16.

 The housing 11 and the plug 12 cooperate only with the second passage 16 and therefore do not interfere with the first passage 15 which itself remains always free, so that the intake gases from the nozzle 9 can always freely feed the first turbulent intake duct 5, after having passed through the common passage 19 and the second passage 15 formed in the body 18.

 As seen more precisely in Figure 4, the plug is constituted by a cylindrical part 12 of dimensions corresponding substantially to those of the housing 11 and which has a transverse opening 22, opening laterally.

 The opening 22 is shaped so that when the plug 12 is in the open position, cf. Figure 2, it continuously extends the corresponding interior surfaces of passages 19 and 16 so as not to generate any pressure drop against the flow of intake gases.

 The positioning of the plug 12 substantially at the junction between the common passage 19 and the second passage 16, eliminates any dead space when the plug 12 is in the closed position, cf. FIG. 3. In addition, the convex shape of the shut-off face of the plug 12 facilitates the flow of the intake gases from the common passage 19 to the first passage 15.

 The plug 12 is rotated by maneuvering means 17 which include a drive pinion 14 fixed to the axial end of the plug 12 opening out of the housing 11, on which acts a rack 13 actuated by a driven drive system not shown, such as a manometric capsule controlled by the engine load, the lung of which is attached to one end of the rack, for example attracted against a return spring by a source of vacuum. This vacuum can be that prevailing in the intake manifold 7 downstream of the throttle valve in the case of a spark ignition engine or by the vacuum generated by a vacuum pump and adjusted by an electromagnetic valve controlled according to the position of the accelerator pedal in the case of a compression-ignition engine.

 Such an operating system can individually drive each bushel 12 or simultaneously drive all of the four bushels necessary for controlling the admission of the four combustion chambers.

 The operating means described are not limiting and can be replaced by any equivalent means (screw-nut systems, rods, etc.). Similarly, the actuator can be produced in an equivalent form in hydraulic or electrical form and can be controlled by an electronic control system according to the operating conditions of the engine (this electronic control system can for example be the electronic engine control system which controls for example the quantity of fuel to be injected, the instant of ignition of the spark plugs, etc.).

 Under the action of the operating means 17 the plug 12 pivots in its housing 11 between two separate extreme positions. The first position is represented in accordance with FIG. 3. In this position, the plug 12 comes to mask, via its convex obturation face, the inlet orifice of the second passage 16, thereby preventing gases from d admission from the manifold 9 and the common passage 19 to flow through the second passage 16 and therefore through the second straight intake duct 6 supplying the combustion chamber 4.

 In this first position of the plug 12, the combustion chamber 4 of the engine is then supplied with intake gas through its only first turbulent duct 5, so that the admitted intake gases are then subjected to an overall movement ordered generator of strong turbulence.

 The second position is shown in accordance with FIGS. 1 and 2. In this position, the plug 12 is pivoted by a predetermined angular value so as to match the opening 22 with the passages 19 and 16 and thus free the orifice. entrance to passage 16 and allow the free movement of admission gas through this passage. In this second position of the plug 12, the combustion chamber 4 of the engine is then supplied by its two intake ducts 5 and 6.

 The operation of the power supply control device of an internal combustion engine is, as described above, as follows.

 During the operating phases at low loads, the operating means 17 controlled by the high vacuum prevailing in the intake manifold maintain the plug 12 in its first position, preventing the circulation of the intake gases through the second conduit 6. The combustion chamber 4 is then supplied by its only first conduit 5 so as to generate turbulence in the intake gases perfectly suited to such engine operating ranges.

 During the full load operating phases, for example above a predetermined vacuum threshold value, the operating means 17 then pivot the plug 12 into its second position so as to release the circulation of the intake gases through the second conduit 6. The combustion chamber 4 is then supplied simultaneously by its two intake conduits 5 and 6 in a manner perfectly suited to such operating conditions.

 When the load decreases and returns below the vacuum threshold value retained, the operating means recall the plug 12 in its first position so as to again close the second passage 16 and prohibit the circulation of the intake gases through the second conduit 6.

 The dimensioning as well as the choice of the different materials used to produce the various elements of the intake device according to the invention and in particular the system for maneuvering in rotation of the plug 12, are operated for each type of engine by prior tests.

 In an alternative embodiment not shown, it is possible to provide transverse nozzles through the plug 12 to allow a predetermined intake gas flow rate through the second passage 16 and therefore through the second conduit 6 when the plug 12 is moved in its first position.

 Of course, the invention is in no way limited to the embodiment described and illustrated, which has been given only by way of example.

 On the contrary, the invention includes all the technical equivalents of the means described and their combinations if these are carried out according to the spirit.

 Thus, the intake conduits 5 and 6 formed in the cylinder head 3 can be of any shape whatsoever.

 Thus, the stroke of the plug 12 can be limited so as to close off in its first position only partially the entry orifice of the passage 16. Similarly, the rotation of the plug 12 between the two aforementioned limit positions can take place progressively according to the engine operating conditions from a map associating openings of passage 16 and engine operating conditions, map previously stored in the memory of the engine control computer.

 Thus, the intake device can also relate to a so-called variable acoustic intake making it possible to optimize the filling of the engine regardless of the engine rotation speed, using two separate intake paths per combustion chamber: a first path ( for example of great length and of small section) being used for the operations at low revs and a second path (for example short and of large section) being used for the operations at high revs.

 Thus, the body 18 inside which the passages 15, 16, 19 and the closing element 12 are formed, can also serve as a support for a fuel injector, in the case of an indirect injection engine. Likewise, the body 18 can be directly integrated into the intake manifold 7 or even into the cylinder head 3.

 Thus, it is possible to provide a similar shutter device in the case where the body 18 has two separate passages extending between the two faces 21 and 20 and no longer two twinned conduits 15. and 16 gathered in. Y as shown in the drawings, the plug 12 can then be arranged at any point of the second passage.

Such an arrangement is more particularly suitable when the intake manifold comprises first and second pipes intended to extend respectively the first and second corresponding intake ducts 5 and 6 formed in the cylinder head.

Claims (5)

[1] Intake device for internal combustion engine, of the type comprising for each combustion chamber (4) at least a first (5) and a second (6) intake ducts arranged inside a cylinder head (3), at least one tube (9) of an intake manifold (7) extending said intake ducts outside the cylinder head (3) and piloted shutter means (10) interposed between said ducts d intake (5,6) and said tubing (9) for selectively opening or closing said second intake duct (6) in response to the operating conditions of the engine, characterized in that said shutter means comprise a closing element (12 ) sliding along a seat (11), said closure element (12) being pivotally mounted and having at least one sealing face in the form of a surface of solid of revolution.  (2] Intake device for internal combustion engine according to claim 1, characterized in that said first intake duct (5) is shaped to cause a vortex movement of the intake gases and in that said second duct intake (6) is shaped to favor the filling of the combustion chamber (4). [3] Intake device for internal combustion engine according to any one of claims 1 to 2, characterized in that said seat of said closure element (12) is constituted by the inner walls of a corresponding cylindrical housing (11 ) formed in a body (10), said body (10) being interposed between the cylinder head (3) and the intake manifold (7) and comprising a first (15) and a second passage (16) intended respectively to be connected by their outlet orifices with the inlet orifices of said first and second intake ducts (5,6) and by their inlet orifices with said tubing (9) of said intake manifold (7). [4] Intake device for internal combustion engine according to claim 3, characterized in that said housing (11) opens through the second passage (16) in a direction substantially perpendicular to the axis of said second passage (16) . [5] Intake device for internal combustion engine according to any one of claims 2 to 4, characterized in that said closing element is constituted by a plug (12) of dimensions corresponding substantially to those of said housing (11) , said plug (12) having a transverse opening (22) opening laterally.  t6] Intake device for internal combustion engine according to any one of claims 3 to 5, characterized in that said inlet ports of the first (15) and second passages (16) formed through said body (10) open into a common passage (19), said common passage (19) being connected by its inlet orifice to the outlet orifice of said tubing (9) of said intake manifold (7) and in that said housing ( 11) is positioned at the right of the connection zone between said second passage (16) and said common passage (19). [7] Device for controlling the supply of an internal combustion engine according to claim 1 to 6, characterized in that said closure element (12) is rotated by maneuvering and controlled immobilization means comprising a pinion (14), a rack (13) and a pneumatic actuator controlled from the engine load.