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(11) | EP 2 354 497 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Air delivery device for internal combustion engines |
| (57) Air delivery device for internal combustion engines, comprising: - an air induction passage (2) for directing the passage of air towards at least one combustion chamber of said internal combustion engine, - a throttle valve assembly (5) having a throttle valve (11) operable between a first position wherein said throttle valve substantially closes said induction passage to the passage of air, and a second position wherein said throttle valve opens said air induction passage to the passage of air. The throttle valve (11) rotates about a rotation axis (18) lying outside the air induction passage (2). |
BACKGROUND OF THE INVENTION
[0002] Air delivery devices are used to regulate and/or control air flow through a system, for example into an internal combustion engine for motor vehicles.
[0003] In modem engines having electronic fuel injection systems, the onboard controller must be able to determine how much air flow is entering the engine in order to be able to compute the necessary mass of fuel to inject into the air flow or directly into the combustion chamber for combustion. Of course, such computation also depends on other factors such as desired richness or leanness to meet fuel emission standards, fuel consumption efficiencies, cold starts, and so on.
[0004] Butterfly-type air throttles are generally used to regulate air flow. A rotation sensor is connected to the butterfly throttle to determine its position and hence derive an air flow estimation through the air delivery device.
[0005] However, butterfly valve throttles are wholly contained within the air passage, which introduce turbulence and other inefficiencies, especially at high air flow rates.
[0006] Sliding guillotine-type throttle valves were developed to address this problem. Such throttle valves present a sliding guillotine that slides in and out of the air passage. At high flow rates, therefore, there is almost no structural disturbance to the laminar flow of air through the air delivery device. Nonetheless, this type of air delivery device suffer from the disadvantage that the linear sensors required to compute the air flow are expensive, difficult to source, and prone to malfunction for general public use.
SUMMARY OF THE INVENTION
[0008] According to an embodiment, the air delivery device for internal combustion engines, comprises:
- an air induction passage for directing the passage of air towards at least one combustion chamber of said internal combustion engine,
- a throttle valve assembly having a throttle valve.
[0009] As the rotation axis is outside the induction passage, the open position has a much reduced rate of turbulences. The air delivery device is more efficient over a greater range of operating conditions. As the throttle valve does not slide, the guiding of the valve movement and the sensing of the valve position are much simpler. Therefore such an air delivery device is more efficient or cheaper to manufacture than traditional devices. It is also more robust, which is particularly interesting for trial motorbikes.
[0010] Preferably, said throttle valve assembly comprises a throttle body presenting a cavity extending transversally from the air induction passage and adapted for receiving said throttle valve and for allowing movement of the throttle valve between its said first and second positions. The throttle valve is a substantially flat plate extending along a plane perpendicular to the rotation axis. This reduces the size of the cavity in which the throttle valve moves.
[0011] According to a particular embodiment, the rotation axis is parallel to the direction of air flow within said air induction passage. This shortens the stroke of the throttle valve across the induction passage. Alternatively, the rotation axis may be tilted relatively to that direction by an angle under 40°. This provides flexibility to improve the overall size of the air delivery device. Any angle between 0 to 40° may be suitable like an angle under 15°, in particular under 5°.
[0012] According to another embodiment, the throttle valve is radially mounted to a shaft entering into the cavity. Such shaft may be connected to a throttle-valve actuator, and preferably to a position sensor.
[0013] According to another embodiment, the air delivery device further comprises a fuel injection system for injecting fuel into the air induction passage. Such a device provides the same service as a traditional carburettor. Therefore an improvement of an engine fitted with a traditional carburettor is simplified.
[0014] In an other aspect, the invention also covers internal combustion engines or motorbikes, four-wheel motorbikes, quads, seadoo or kartings, comprising such an air delivery device.
[0015] In some embodiments, one might also use one or more of the features defined in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Other characteristics and advantages will readily appear from the following description of various embodiments, provided as non-limiting examples, and of the accompanying drawings.
[0017] On the drawings:
- Figures 1 and 2 are two different perspective views of an air delivery device according to an embodiment to the present invention,
- Figure 3 is an exploded view of the air delivery device of figures 1 and 2,
- Figures 4 and 5 are side elevation and plan views respectively of the air delivery device of figure 1,
- Figures 6 and 7 are cross-sectional views across VI-VI and VII-VII respectively as indicated on figure 5,
- Figures 8 to 10 are partial perspective views of the air delivery device of figure 1 illustrating in greater detail the throttle valve assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The air delivery device 1 comprises an air induction module 3 having a bore 2 extending along an air flow parallel to direction X, between an inlet portion 3A and an outlet portion 3B. The bore 2 defines an air induction passage 2. The bore 2 may for example be straight or may be venturi-shaped. The inlet portion 3A may be connected to a source of air, which may for example be ambient air or compressed air with or without an intermediate air filter. The outlet portion 3B is for example connected to a combustion chamber of an internal combustion engine.
[0020] The air induction passage 2 is sized according to design parameters such as air flow rates, but will generally present a diameter in the range of 14-60 mm, for example 39 mm.
[0021] The external peripheral surface of the inlet portion 3A and the outlet portion 3B may present a circumferential groove 7 adapted to facilitate the connection and seal of the air induction module 1 with a connector, for example a rubber hose. The groove 7 may for example be a circumferential cut or bead.
[0022] The air delivery device 1 further comprises a throttle valve assembly 5 arranged in the air induction passage 2 intermediate the inlet and outlet air portions 3A, 3B.
[0023] As more clearly seen in figures 3 to 7, the throttle valve assembly 5 comprises a throttle valve body 9 enclosing a throttle valve 11.
[0024] The throttle valve body 9 comprises an inlet side body 9A and an outlet side body 9B connected to the inlet and outlet air portions 3A, 3B of the air induction module 3 respectively. The throttle valve body 9 is for example injection molded out of aluminium metal or an aluminium alloy.
[0025] The inlet and outlet side bodies 9A, 9B each present an opening 6 in correspondence to the bore 2 defining the air induction passage. The throttle body 9 may be integrally molded with the air induction module 3 at the opening 6, as illustrated, or may be machined from the same block, or may be mechanically attached to each other with appropriate fixing means.
[0026] The inlet side portion and the outlet side portion 9A, 9B of the throttle body 9 are mechanically fixed together by appropriate means of fixation 13A, for example nuts and bolts 13A traversing corresponding bores 13, and may further be fitter with sealing gaskets at their mating surfaces.
[0027] The throttle body 9 further presents an internal substantially flat cavity 15 extending substantially along a plane normal to the air passage direction X. For example, the cavity 15 may be substantially quarter-circle shaped. The cavity 15 entirely encloses the opening 5 of the air induction passage 2.
[0028] The throttle body 9 further comprises, within the cavity 15 on one and/or the other of the side bodies 9A, 9B, a circular recess or blind hole 17 defining a central axis 18. The axis 18 is substantially parallel to the air passage direction X.
[0029] Furthermore, a through-hole 19 is provided traversing the entire throttle body 9 concentrically with the axis 18. The through-hole 19 is diametrically smaller than the circular recess 17.
[0030] As represented more clearly on figures 3, and 7 to 10, the throttle valve 11 is enclosed by the throttle body 9, and more specifically, the throttle valve 11 is arranged within the space defined by the cavity 11 between the inlet side body 5A and an outlet side body 5B.
[0031] The throttle valve 11 is typically made of steel and presents a substantially flat ovate form, extending from a broader valve portion 11 A sized to cover the opening 6, and a smaller mounting portion 11B. The mounting portion 11B further comprises a protrusion sized to rotationally fit within the circular recess 17 of the throttle body 9. The throttle valve 11 is made from a thin plate, for example 1 to 12 mm, such as 2.7 mm. The thickness of the throttle valve will be preferably substantially equal, accounting for tolerances, to the depth of the cavity 15.
[0032] The throttle valve assembly 5 further comprises a throttle shaft 21 having a cylindrical body rotationally fixed to the throttle valve 11 via a raised portion 21 A at the shaft 21 mid-section. The raised portion 21 A is fitted to a corresponding key-opening 11 C centred at the rotational centre of the mounting portion 11 B of the valve 11. The valve 11 may for example be fixed to the shaft 21 by interference fit, welding, or adhesive means.
[0033] The raised portion 21A may also for example present two parallel flat sides to prevent rotational slip between the valve 11 and the shaft 21.
[0034] Furthermore, each extremity of the throttle shaft 21 presents end portions 21B, 21C adapted for non-rotational mounting of modules, for example a throttle actuator, a position sensor, or yet other sensing or actuation means.
[0035] Referring to figures 7 to 10, according to the present exemplary embodiment, a throttle actuator 23 is fixed to the end portion 21 B of the shaft 1.
[0036] The throttle actuator 23 may present a cam portion 23A mounted on the shaft 21. The cam portion 23A presents a circumferential groove 23B adapted for retaining for example a throttle cable connected to an accelerator handle or pedal actuated by a user.
[0037] Furthermore, a throttle position sensor 31 is fixed to the other end portion 21C of the shaft 21. In the presently described embodiment, the throttle position sensor 31 measures the position of the throttle 11 via the rotational position of the shaft 21. The signals generated by the position sensor 31 may be analogue or digital. The sensor 31 may for example present an electronic connector 31 A for connecting to a controller, for example an Engine Control Unit (ECU), also known as Full Authority Digital Engine Control (FADEC). Such rotational position sensors 31 are well known to the skilled person, and are commonly available on the market, for example under the brand CTS.
[0038] The shaft 21 is mounted in the through-hole 19 of the throttle valve assembly 5, such that the shaft is concentric with axis 18. In this position,
- the shaft 21 extends longitudinally along the X direction within the through-hole 19,
- the throttle valve 11 is arranged such that the mounting portion 11 B fits within the circular recess 17, thereby permitting for rotational movement of the valve 11 inside the cavity 15 about the shaft 21,
- the throttle 21 is rotationally locked to the shaft 21 via the mounting portion 11B and the raised portion 21A,
- the throttle valve is enclosed in rotation by the cavity 15,
- the valve portion 11 A of the throttle valve 11 is rotatable between a first position ("closed position") (see figure 8) wherein the throttle valve 11 substantially closes the opening 6 and the air induction passage 2 to the passage of air there through, and a second position ("open position") (see figure 9) wherein the throttle valve 11 clears the opening 6 and the air induction passage 2 is free to the passage of air there through, and
- the throttle actuator 23 and the sensor 31 are positioned external to the throttle body 9.
[0039] Referring to figures 3 to 5 and 7, a torsional spring 25 may be fitted around the shaft 21 between the throttle actuator 23 and the throttle body 9 in order to bias the throttle actuator 23 in a position whereby the valve 11 is in the closed position, or a substantially closed position permitting engine idling conditions.
[0040] According to an exemplary variant of the present embodiment, the air delivery device may further comprise a fuel injector system 35 adapted for injected combustion fuel into the air induction passage 2. The fuel injector system 35 comprises an electronic controller module and a corresponding electrical connector 37, and is adapted to control the volume of combustion fluid injected in function of the volume of air flow through the air induction passage 2. The fuel injector system 35 may for example be arranged through an opening 39 provided downstream of the throttle valve 11.
[0041] Fuel injector system per se are well known in the art, and the skilled person will easily be able to adapt an air delivery device 1 as described herein with an appropriate fuel injector system 35, for example the Delphi injector reference M35-Mini-25384016-Sh3, or Magneti Marelli injector reference IWP048.
[0043] The air delivery device 1 as described is positioned between one or more air intake valves of a naturally-aspirated or forced-induction internal combustion engine and a source of air.
[0044] Air thus flows through the air delivery device 1 along air induction passage 2 from the inlet portion 3A to and the outlet portion 3B, passing via the throttle valve assembly 5.
[0045] The user, wishing to control the power developed by the internal combustion engine by controlling the amount of air (oxygen) that enters the engine per stroke of the engine, actuates for example the foot pedal of a motor vehicle or the handle of a motorcycle.
[0046] The activation of the foot pedal or the handle induces rotation of the cam 23A of the throttle actuator 23, which results in a rotation of the throttle valve 11.
[0047] The position of the throttle valve 11 with respect to the opening 6 of the air induction passage 2 determines the smallest cross-sectional area of the air induction passage 2, which is in turn correlated to a specific mass or volume of air which the engine is able to aspirate, thus determine the ultimate power able to be generated by the engine.
[0048] The throttle position sensor 31 concurrently senses the position of the shaft 21 to determine the position of the throttle valve 11. From the position of the throttle valve it is possible to determine the mass of air flow through the air delivery device 1. This rotational position information may be communicated to the ECU to determine the fuel injection required by the fuel injector system 35 in function of the speed of the engine, the leanness of the operation cycle desired, and yet other factors.
[0050] In particular, the air delivery device 1 according to the present invention may comprise an electronically controlled throttle actuator 23 actionned by electronic impulse, rather than physical connection to a pedal or handle. This is commonly referred to as fly-by-wire.
1. Air delivery device for internal combustion engines, comprising an air induction passage
(2) for directing the passage of air towards at least one combustion chamber of said
internal combustion engine and a throttle valve assembly (5) having a throttle valve
(11), said throttle valve (11) being operable between a first position wherein said
throttle valve substantially closes said induction passage to the passage of air,
and a second position wherein said throttle valve opens said air induction passage
to the passage of air, characterized in that the throttle valve (11) rotates about a rotation axis (18) lying outside the air
induction passage (2).
2. Air delivery device according to claim 1, wherein said rotation axis is parallel to
the direction of air flow within said air induction passage.
3. Air delivery device according to claim 1, wherein said rotation axis is tilted relatively
to the direction of air flow within said air induction passage by an angle under 40°.
4. Air delivery device according to any one of the preceding claims, wherein said throttle
valve (11) is a substantially flat plate extending along a plane perpendicular to
the rotation axis (18).
5. Air delivery device according to any one of the preceding claims, wherein said throttle
valve assembly comprises a throttle body (9) presenting a cavity (15) extending transversally
from the air induction passage (2) and adapted for receiving said throttle valve (11)
and for allowing movement of the throttle valve between its said first and second
positions, said throttle valve being radially mounted to a shaft (21) entering into
the cavity (15).
6. Air delivery device according to claim 5, wherein the throttle valve is connected
to a throttle-valve actuator (23) via the shaft (21).
7. Air delivery device according to claim 6, wherein the actuator (23) comprises a throttle
cable retention means and a cam portion (23A) presenting a circumferential groove
(23B) for receiving the throttle cable.
8. Air delivery device according to any one of the preceding claims, further comprising
a sensor (31) adapted for measuring the rotational position of the throttle valve
(11).
9. Air delivery device according to both claims 5 and 8, wherein the sensor is mounted
to the shaft (21).
10. Air delivery device according to any one of the preceding claims, further comprising
a fuel injection system (35) for injecting fuel into the air induction passage.
11. Air delivery device according to claim 10, wherein the fuel injection system is mounted
to the throttle valve assembly.
12. An internal combustion engine comprising an air delivery device according to any one
of the preceding claims.
13. A motorbike comprising an air delivery device according to any one of the preceding
claims 1 to 11.