WO2019000022A1

WO2019000022A1 - Engine intake

Info

Publication number: WO2019000022A1
Application number: PCT/AU2018/050619
Authority: WO
Inventors: Anthony PARLE
Original assignee: Parle Technologies Pty Ltd
Priority date: 2017-06-27
Filing date: 2018-06-22
Publication date: 2019-01-03

Abstract

An air intake (1) for an internal combustion (2) comprising: at least one runner (3) wherein the runner (3) includes an inlet (5) fluidly connected to an outlet (7), wherein the runner (3) provides a passage (9) for air (11) (or fuel air mixture) to a respective intake port (13) of a combustion chamber (14); and a regulator (17) to vary an effective cross-section (19) of a portion (20) of the runner (3), such that during intake a velocity of air to the intake port (13) is substantially consistent throughout an operating revolution range and the regulator (17) varies the effective cross-section (19) to adjust an air flow rate to the combustion chamber (14).

Description

"Engine intake"

Technical Field

[0001] The present disclosure relates to an air intake for an internal combustion engine. The air intake may be used for internal combustion engines such as those used in motor vehicles.

Background

[0002] Internal combustion engines, such as those used in motor vehicles such as cars, truck, motorcycles and the like, require two main inputs for combustions - fuel and oxygen. Fuel(s) may include petrol (gasoline), diesel, liquidfied petroleum gas (LPG), ethanol, although this is not an exhaustive list. Oxygen is typically obtained from air in the surrounding atmosphere. Induction of air into an internal combustion chamber may include natural aspiration (where intake of air is at approximately atmospheric pressure) and forced induction (where intake of air is compressed with devices like turbocharges or superchargers).

[0003] The shape and structure of an air intake can affect the properties of air into the engine and affect the efficiency and performance of an engine. Variable-length intake manifolds (variable-length intake runners) may be used to provide different paths for air to flow into the engine. This may be used to vary the turbulence and/or vary the velocity of air into the combustion chamber. The length of the intake may be varied based on the harmonic resonance of the intake, the engine, and in combination with the operating revolutions per minute (RPM) (or range of RPM). That is, different RPM (or range of RPMs) may dictate different lengths so that harmonic resonance provides a pressure wave (or pulse) that is tuned to provide optimum pressure into the cylinder.

[0004] Any discussion of documents, acts, materials, devices, articles or the like which have been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

[0005] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Summary

[0006] An air intake for an internal combustion engine comprising:

- at least one runner wherein the runner includes an inlet fluidly connected to an outlet, wherein the runner provides a passage for air, or fuel air mixture, to a respective intake port of a combustion chamber);

- a regulator to vary an effective cross-section of a portion of the runner, such that during intake a velocity of air to the intake port is substantially consistent throughout an operating revolution range and the regulator varies the effective cross-section to adjust an air flow rate to the combustion chamber.

[0007] The operating revolution range is a range for the revolutions per minute (RPM) of the internal combustion engine during operation. In some examples, this may include a range between idle and the maximum safe RPM of the engine. For example, between 1000 RPM and 7000 RPM. In other examples, this may be a subset, of a safe engine operating range of the engine (for example, between 2000 RPM and 4000, where the engine may also operate safely outside this range). It is to be appreciated that the velocity of air to the intake port may not be constant at all times. For example, during operation of the internal combustions engine the intake port may have respective valves that cyclically open and close. When the valves are fully closed, this will stop the flow of air. However, the flow of air can be cyclically consistent whereby air flow to the intake port, such as when the valve is open, is at a consistent velocity at that stage of the cycle and substantially consistent despite different engine RPM within the operating revolution range.

[0008] In some examples, this may include providing consistent velocity of air with respect to a crank angle. For example, it may be desirable to have the velocity of air at a particular specified velocity when the cylinder is at bottom dead centre between the intake and compression stroke, which in turn, may result is a corresponding pressure of the air irrespective of the engine RPM. In some examples, this may include providing a consistent velocity so that at the time an intake valve closes, the velocity of air is consistent irrespective of RPM. In yet another example, the velocity of air is specified such that a peak pressure at the intake port corresponds to the time the intake valve closes. This may advantageously result in a greater amount of air (and volumetric efficiency) to the engine.

[0009] The air intake may further comprise: a regulator actuator to operate the regulator; and a regulator controller to control operation of the regulator actuator, wherein the regulator controller is operable based on one or more control parameters.

[0010] The one or more control parameters comprise: an engine speed; a fuel throttle setting; air temperature; or induction air pressure.

[0011] In some examples, the one or more control parameters may also comprise valve timing, wherein the regulator controller controls operation of the regulator actuator such that peak pressure at the intake port corresponds to closing of an intake valve.

[0012] In some examples of the air intake, the portion of the runner includes an aperture and the regulator includes a plug, wherein the plug is displaceable through the aperture to vary the effective cross-section of the portion. In some examples, the aperture includes a substantially circular cross-section.

[0013] In some examples, at least part of the aperture includes an inner wall portion with a frustoconical surface. In some examples, the plug includes an outer surface portion that has a frustoconical surface.

[0014] The intake may be provided for an internal combustion engine having a plurality of cylinders with respective combustion chambers wherein the air intake comprises a plurality of runners each associated with a respective combustion chamber.

[0015] The intake may further comprises a plenum housing, wherein the inlet of the at least one runner is fluidly connected to a chamber of the plenum housing, and wherein the plenum supplies the air or an fuel air mixture.

[0016] In some examples, the runners have respective regulators and where one or more regulators are synchronised to one another. In further examples, the one or more regulators are synchronised with each other via a regulator cam shaft. In some examples, a common regulator actuator operates the regulator cam shaft.

[0017] The air intake for an internal combustion engine described above may be for a reciprocating piston engine.

[0018] The air intake for an internal combustion engine described above may be for a wankel rotary engine.

[0019] There is also disclosed an internal combustion engine having the air intake as described above.

[0020] A method of introducing air from an air intake to an internal combustion engine at a desired velocity, the method comprising:

- determining the desired velocity of air for the internal combustion engine;

- determining, based on at least one control parameter, a desired air flow rate for the engine;

- calculating a desired effective cross-section for a runner of the air intake, based on the desired velocity of air and the desired air flow rate; and

- sending, to a regulator actuator, a control signal to actuate a regulator to vary an effective cross-section of the runner to the calculated desired effective cross-section.

[0021] In some examples, the control parameter may comprise one or more of: an engine speed; valve timing; a fuel throttle setting; air temperature; and induction air pressure.

[0022] In some examples, the method further comprises calculating a desired effective cross-section for a runner such that the timing of peak pressure at an intake port corresponds to closing of an intake valve. Brief Description of Drawings

[0023] Examples of the present disclosure will now be described with reference to the following drawings:

[0024] Fig. 1 illustrates a cross-sectional schematic of an internal combustion engine having an air intake;

[0025] Figs. 2(a) to 2(c) is a sequence showing the air intake at different stages of adjustment;

[0026] Fig. 3 illustrates a perspective view of another example of an air intake having three runners in series;

[0027] Fig. 4 is a cross-sectional schematic of three runners in series, including a plenum housing;

[0028] Fig. 5 is a flow diagram of a computer-implemented method of introducing air from an air intake to an internal combustion engine at a desired velocity;

[0029] Fig. 6 illustrates a perspective view of yet another example of an air intake having three runners in series with fuel injectors;

[0030] Fig. 7 illustrates a side view of a runner of Fig. 6;

[0031] Fig. 8 illustrates a partial cross-sectional perspective view of a runner with a centrally mounted injector;

[0032] Figs. 9(a) to 9(d) illustrate a four-stroke cycle; and [0033] Fig. 10 is a schematic example of a processing device. Description of Embodiments

Overview

[0034] An example of an internal combustion engine 2 having an air intake 1 to supply air to a combustion chamber 14 will now be described with reference to Fig. 1. The internal combustion engine 2 includes an engine block 116 that defines cylinder walls 117 of a cylinder 15 where a cylinder head 122 is provided a one end of the cylinder 15. A

reciprocating piston 115 is provided inside the cylinder 15 so that the piston 115, cylinder head 122 and the engine cylinder 17 define a combustion chamber 14. A crankshaft 118 is driven by the reciprocating piston 115 via a connecting rod 120 to convert linear reciprocating motion to rotational motion. The crankshaft 118 provides an output that may be transmitted along a power train. The internal combustion engine 2 includes an air intake 1 and an exhaust 133. One or more valves 124, such as poppet valves, may open and close to allow air 11 or a fuel air mixture to be introduced into the combustion chamber 14 via the air intake 1. The exhaust 133 may also include one or more valves 126 that open and close to allow

combustion gasses 128 to be exhausted from the combustion chamber 14.

[0035] The air intake 1 includes at least one runner 3, wherein the runner 3 includes and inlet 5 fluidly connected to an outlet 7. The runner 3 provides a passage 9 for air 11, or fuel air mixture, to a respective intake port 13 of the combustion chamber 14.

[0036] The air intake 1 further includes a regulator 17 to vary an effective cross-section 19 of a portion 20 of the runner 3. During intake, a velocity of air to the intake port 13 may be substantially consistent throughout an operating revolution range. That is, the velocity of air 11 may be substantially constant at respective crank angle, for a wide range of different RPMs (revolutions per minute). The regulator 17 varies the effective cross-section 19 to adjust an air flow rate to the combustion chamber 14.

[0037] This adjustment of air flow rate allows increased or decreased amounts of air 11 to the combustion chamber 14 as required for respective RPMs. For example, at higher RPMs where more air is required the effective cross-section 19 can be increased to increase the overall amount of air 11 to the combustion chamber 14. Conversely, at lower RPMs the effective cross-section 19 can be decreased to decrease the overall amount of air 11 to the combustion chamber 14 whilst keeping a consistent velocity of air 11.

[0038] Having a substantially consistent and constant velocity of air may be advantageous as it may allow consistency and optimisation of an engine for a designed engine

configuration. Having air flowing a consistent velocity may also provide more charge into the combustion chamber 14.

Description of an example of the air intake 1

[0039] An example of the air intake 1 will now be described in further detail with reference to Figs. 1 and 2. The runner 3 has an inlet 5 fluidly connected to the outlet 7 to provide a passage 9 of air to the intake port. The runner 3 includes a portion 20 that has an effective cross-section 19 that can be varied as discussed in further detail below.

[0040] In some examples, the portion includes an aperture 23. In some examples, the aperture 23 has a substantially circular cross-section. In further examples, the aperture 23 has an inner wall portion 41 that has a frustoconical surface. That is, the inner wall portion 41 may have a surface with a partial conical surface. The frustoconical surface of the inner wall portion 41 may surround a central axis 43, so that the circular cross-section is larger when proximal to the inlet 5, and the circular cross-section is smaller when proximal to the outlet 7.

[0041] The air intake 1 also includes a regulator 17 to vary the cross-section of the runner 3. In some examples, the regulator 17 includes a plug 25 that is displaceable through the aperture 23 to vary the effective cross-section 19 of the portion 20. The plug 25 may include an outer surface portion 44 that, at least in part, has a frutoconical surface or a fully conical surface.

[0042] In some examples the outer surface portion 44 of the plug 25 may be complimentary with the surface of the inner wall portion 41 of the aperture 23 of the runner 3. In some examples, these frustoconical surfaces may be parallel to one another to provide an annular gap 46 that is tapering, but with a consistent distance between the inner wall portion 41 and the outer surface portion 44. [0043] The angles of the outer surface portion 44 of the plug 25 and the surface of the inner wall portion 41 of the aperture 23 of the runner may be selected, by designed, to provide the consistent and controllable velocity. This may include specifying a desirable velocity of air during intake for an operating revolution range (or a desirable subset of that range). From this specification, the respective angles may then be calculated and tested by simulation to provide the desired angles. Thus in some examples, the surfaces may be at different angles (i.e. not parallel as illustrated in Fig. 7).

[0044] By adjusting the relationship of the angles, the properties (including the respective cross-sectional areas of the annular gap) may be adjusted to achieve the desired volumetric efficiency at various RPMs in the operating revolution range.

[0045] It is to be appreciated that in other examples, the outer surface portion 44 of the plug 25 and the surface of the inner wall portion 41 of the aperture may have a surfaces that are modified conical surfaces that are concave or convex.

Regulator actuator 22 and regulator controller 21

[0046] The air intake 1 may also include a regulator actuator 22 to displace the plug 25 along the central axis 43. In some examples, the regulator actuator 22 may include a linear stepper motor to move the plug 25 to the desired displacement along the central axis 43. In other examples, the regulator actuator 22 may include a system of cams to displace the plug 25 (as illustrated in Fig. 4). This may include one or more cams 26 to move the plug 25 along the central axis 43. In some examples, the cam may be operable via a regulator cam shaft 30 which, in turn, operable by an actuator 31 (such as a rotational stepper motor). In further examples, the plug 25 may be biased by one or more springs in at least one direction along the central axis 43.

[0047] The regulator actuator 22 may in turn be controlled by a regulator controller 21. The regulator controller 21 may operate the regulator 17 to achieve a desired effective cross- section of the portion 20 based on one or more control parameters.

[0048] The regulator controller 21 may utilise one or more sensor systems to determine control parameters based on one or more of: - an engine speed;

- valve timing;

- a fuel throttle setting;

- air temperature;

- induction air pressure.

[0049] The engine speed (e.g. RPM) may be indicative of how much oxygen (and hence air flow) that is required for the engine at that engine speed. The valve timing affects when the air is introduced into the cylinder based on the crank angle (and in turn the position of the piston). In some examples, this may be fixed by design but in some alternative engine designs the valve timing (as well as valve lift) may be variable. The fuel throttle setting may also be a control parameter relevant to the air flow required and this, in turn, may be based on the stoichiometric ratio for fuel and oxygen. Further relevant parameters may include the air temperatures and induction air pressure as this can affect the density of air (and hence the amount of oxygen for a given volume of air). These control parameters may be determined by sensor such as tachometers, thermometers, air pressure sensors, displacement sensors (e.g. in relation to the position of the plug 25 and/or engine fuel throttle), etc.

[0050] The regulator controller 21 may include a processing device to receive information, including data from the sensors, to determine a desired setting (such as effective cross-section 19) for the air intake 1 and to provide corresponding control signals to the regulator actuator 22. An example of a processing device 21 is discussed in further detail below with reference to Fig. 10.

Operation of the air intake to alter the effective cross-section 19

[0051] The operation of the air intake 1 to alter the effective cross-section 19 is best illustrated in the sequence shown in Figs. 2(a) to 2(c).

[0052] In Fig. 2(a), a tip 45 of the plug 25 is at the cross-section 19 of the portion 20. Thus the effective cross-section 19' at the portion in this configuration is slightly less that the approximate area of a circular cross-section at the portion 20. It is to be appreciated that the effective cross-section 19' may be less than the theoretical circular cross-section due to the aerodynamic drag or other disturbances by the tip 45 of the plug 25.

[0053] In Fig. 2(b), the plug 25 is advanced along the central axis 43 towards the outlet 7. Thus the effective cross-section 19" is reduced due to the tip 45 of the plug 25 occupying at least part of cross-sectional area.

[0054] In Fig. 2(c), the plug 25 is further advanced along the central axis 43 towards the outlet 7. The effective cross-section 19" ' is even further reduced due to plug 25 occupying even more of the cross-sectional area.

[0055] The effective cross-section 19 at plane 40 may be described as:

Effective cross-section = cross-section area of portion (20) - cross-section area of tip (45)

[0056] This area may be calculated as areas of respective circular cross-sections (i.e. r²).

[0057] One advantage of altering the effective cross-section is to assist in maintaining a consistent velocity of air 11 to the intake port 13 whilst allowing adjustment of air flow rate due from the demands of the engine 2 (such as requiring more air flow for higher RPM). It is to be appreciated that the air flow rate (in terms of volume of air at a constant pressure or temperature) may be described as follows:

Air flow rate (cm³ per second) = effective cross-section (cm²) X velocity (cm per second)

[0058] Thus the air flow rate can be adjusted by varying the effective cross-section 19 (whilst keeping velocity substantially constant and consistent). This may be used to assist in maintaining a consistent velocity of air 11. In some examples, the engine 2 may be designed and optimised at a particular velocity of air or a range of velocities. This may assist in more consistent, or complete, mixing of the fuel air mixture and/or combustion of the fuel air mixture. The velocity may also assist in charging of additional air (or fuel air mixture) than other configurations (such as conventional naturally aspirated engines that rely on ambient atmospheric pressure for the flow of air into the cylinder). Method 300 of introducing air to the engine at a desired velocity

[0059] As noted above, it is desirable to vary the effective cross-section to adjust airflow in order have a consistent and desired velocity of air. The regulator controller 21 may assist this process by performing the method 300 as illustrated in Fig. 5. In some examples, this includes determining 310 the desired velocity of air for the internal combustion engine. The desired velocity may be stored in a memory associated with the regulator controller 21. In some examples, an engine may have multiple desired velocities for different profiles, such as a desired velocity for cold starts, a desired velocity for maximum fuel efficiency, a desired velocity for maximum torque and/or power, etc.

[0060] The method 300 also includes determining 320, based on at least one control parameter, a desired air flow rate for the engine 2. The control parameters may include one or more of an engine speed, valve timing, fuel throttle setting, air temperature, and/or induction air pressure. These control parameters may be used to determine how much air (and hence air flow rate) the engine requires.

[0061] In some examples, the controlling the velocity of air, in turn, controls the timing of peak pressure at the cylinder (and intake port) so that the timing of peak pressure coincides with the intake valve closing. This may be advantageous in contributing to a high volumetric efficiency of the engine.

[0062] The method 300 also includes calculating a desired effective-cross section for a runner of the air intake based on the desired velocity and the desired air flow rate. In some examples, this may be calculated based on the formulas described above.

[0063] The method also includes sending 340 to a regulator actuator 22 a control signal to actuate the regulator so that the effective cross-section 19 of the runner is varied to the calculated desired effective cross-section.

Advantages

[0064] The air intake may allow the internal combustion engine to achieve higher volumetric efficiency (i.e. the efficiency of the intake charge of air compared to the swept volume of a cylinder of the engine). The substantially consistent velocity of air to the intake port (which may be considered as controlling air velocity to be consistent with a desired/design velocity) may allow optimisation of the air flow for the particular engine.

[0065] The velocity of air (and the mass) may have momentum and energy to assist the flow to the intake port and cylinder. The momentum of the air flow may be described as a function of the mass and the velocity. The air flow may also have kinetic energy. Both the momentum and kinetic energy of air to the intake port may be affected by the mass of air (which is related to quantity of air that flows in the air intake) as well as the velocity.

[0066] In some examples the momentum and kinetic energy may be increased by increasing the mass of air travelling in the runner. Thus in some examples, having a longer runner (to increase the mass of air travelling in the same direction through the runner) can increase the overall momentum of air to the intake port.

[0067] As an illustrative example, consider a four stroke reciprocating internal combustion engine with valves operable to allow air into the intake port. High momentum (and/or a corresponding high velocity and kinetic energy) of air as the intake valve closes (such as when the piston is around bottom dead centre during an intake stroke) may allow the engine to achieve a volumetric efficiency (VE) greater than 100%. This may include achieving a VE of greater than 100% without forced induction (although it is to be appreciated that the air intake may be configured for forced induction systems).

[0068] Furthermore, controlling the velocity of air, to a desired velocity, may allow timing so that the corresponding timing of maximum inertia through the intake port is optimised, such as near or round closing of the valve during the intake stroke. In some examples, this may include controlling the velocity of air to control the timing of peak pressure of the air to the intake port to be at, or near, the time the intake valve 124 closes. By timing, this may be time relative to a crank angle so that the timing of the peak pressure of air to the intake port will correspond to the time the intake valve 124 closes irrespective of the RPM (i.e. the engine speed). Variation

Example of an air intake with a plurality of runners 3

[0069] Figs. 3 and 4 illustrate another example of an air intake 201. In this example, the air intake 201 includes a plurality of runners 3', 3", 3" ' in series. In some examples, the plurality of runners 3 may be configured for respective combustions chambers 14, such as cylinders 15 of an inline engine. Alternatively, the plurality of runners 3 may be configured for a respective bank of cylinders of a V configured engine.

[0070] Fig. 3 illustrates a cross-section of the middle runner 3" and respective plug 25'. In this example, the plug 25', 25", 25" ' has a frustoconical outer surface having two different profiles. A first outer surface portion 44a has a frustoconical outer surface that is

substantially parallel with the inner wall portion 41 of respective runners 3', 3", 3"' . The plug 25', 25", 25" ' also has a second outer surface portion 44b that has a conical outer surface that ends at tip 45, where the conical outer surface is at a different angle (that tapers to the central axis 43 greater than the surface of the inner wall portion 41. This may assist in flow of air to the intake port 13.

[0071] Referring to Fig. 4, the air intake 201 may also include a plenum housing 27 to provide a chamber 29. Air 28 is fed into the chamber 29 where the air, in turn, is then fed through the inlets 5 and through the runners 3. The air 28 fed into the chamber 20 may be filtered by an air filter upstream. It is to be appreciated that in some examples air 28 may include a fuel air mixture.

[0072] It is also to be appreciated that a turbocharger, supercharger or other forced induction devices may be provided upstream of the chamber 29. An intercooler may also be provided upstream to reduce the temperature of the air 28.

[0073] In some examples, each of the plugs 25', 25", 25" ' may have respective regulator actuators 22. However in other examples (as illustrated in Fig. 4) the plugs 25', 25", 25"' may be synchronised to one another. Accordingly, the plugs 25', 25", 25" ' may be mechanically actuated, or linked, to one another. For example, a regulator cam shaft 30, with a plurality of cams 26, may be provided so that movement of the regulator cam shaft 30 causes synchronised movement of the plugs 25', 25", 25" '. A common regulator actuator 31, such as a stepper motor, may be used to operate the regulator cam shaft 30.

Another example of an air intake 301 with a plurality of runners

[0074] Figs. 6 and 7 illustrate yet another variation of an air intake 301. The air intake 301 includes a plurality of runners 3', 3", 3" ' and respective plugs 25', 25", 25" '. The plugs 25', 25", 25" ' are connected to one another by a common link 51 to synchronise movement with one another. The common link 51 may be connected to pushrods 53, which in turn may be connected to an actuator 31.

[0075] The plurality of runners 3', 3", 3"' may be connected to a common base 55 for mounting to a cylinder head.

[0076] In Fig. 6, the middle runner 3" is partially cross-sectioned which is shown in more detail in Fig. 7. The inlet 5 may include a curve to assist flow of air from the chamber 29 into the aperture 23. In this example, the top of the plug 25 has a lip 57. This lip 57 may be complementary to the inlet 5. In some examples, this allows the plug 25' to close off the inlet 5. This may be useful to stop or reduce air flow in some conditions. In some examples, this may include reducing or closing off air at idle. In other examples, this may include reducing or closing off air to shut down a particular cylinder.

[0077] The outer surface portion 44 of the plug 25 has a sharper taper than the shallower inner wall portion 41 of the runner 3. That is, they are at different angles relative to the central axis 43.

[0078] In some examples, as schematically illustrated in Fig. 7, the annular cross-sectional area 42', 42", 42" ', 42" " of the annular gap 46, perpendicular to the centre axis 43, may be substantially the constant for a given relative displacement of the plug 25 and the runner 3. In some examples, this may be advantageous to provide an annular passage 46 that, although tapering, has a consistent cross section 42 to reduce the Venturi effect. A runner with a centrally mounted fuel injector

[0079] A runner 401 with a centrally mounted fuel injector 61 inside the plug 425. A common fuel line 63 supplies pressurised fuel to a fuel pipe 65 for each of the injectors 61. In this example, the fuel pipe 65 may be a rigid pipe that also serves as a support in which the plug 425 can move (along central axis 43). The plug 425 may be selectively displaced to maintain substantially consistent velocity and to adjust flow rate as discussed above.

[0080] The fuel pipe 65 leads to an inlet 67 of the injector 61. The injector 61 includes a solenoid operated valve 69 to selectively discharge pressurised fuel through a spray tip 71. The solenoid operated valve 69 may receive control signals via an electrical connector 73.

[0081] It is to be appreciated that in other examples, the fuel may be introduced to by direct injection into the cylinder (not shown), a fuel injector at outlet 7 of the runner, by a carburettor to the air (upstream), or other methods.

Description of an internal combustion engine

[0082] Fig. 1 illustrates a schematic example of an internal combustion engine 2. In particular, an engine with a four-stroke cycle for each piston 15. The four-stroke cycle, in general, includes: a power stroke, exhaust stroke, intake stroke and compression stroke. This is illustrated in the sequence of Figs. 9a to 9d. The air intake 1 has not been illustrated in Figs. 9a to 9d for simplicity but it is to be appreciated that the air intake 1 is to be included with the engine 1.

[0083] During the four-stroke cycle, the valves 124, 126 are operated to selectively allow air 11 (or fuel air mixture) into the combustion chamber 14 (the intake stroke in Fig. 9c) and to allow combustions gasses 128 to be exhausted 133 (the exhaust stroke in Fig. 9b). The air intake 1 described above is directed towards supplying air 11 to the combustion chamber 14 during the intake stroke shown in Fig. 9c.

[0084] In some examples, the valves may be operated by a series of cams on a camshaft that is operatively timed with the piston's 115 reciprocating cycle. In some examples, the valve timing and valve lift may be variable depending on engine conditions, loads, etc. to achieve desired efficiency, power, and/or emission requirements. In other examples, the valves may be operated by rocker arms. It is to be appreciated that other intake and exhaust types could be used, such as side ports.

[0085] During the intake stroke, as shown in Fig. 9c, the intake valve 124 is generally open. In some examples, the intake valve 124 may start to open before the cylinder reaches top dead centre between the exhaust stroke and intake stroke. In further examples, the intake valve 124 may fully close after the cylinder passes bottom dead centre (BDC) between the intake stroke and the compression stroke. It is to be appreciated that there may be some variances, for example, the intake valve 124 may begin closing before BDC but does not fully close until after BDC. In other examples the intake valve 124 may begin to close at or around BDC and fully close well after BDC.

[0086] In some examples, the air intake 1 introduces air and the fuel is directly injected into the combustion chamber 14. In other examples, the fuel is mixed with air upstream of valve 124. At, or around, top dead centre of the piston 115 between the compression stroke (as shown in Fig. 9d) and the power stroke (as shown in Fig. 9a) the fuel air mixture in the combustion chamber 14 is ignited. It is to be appreciated that ignition may be affected by various means, such as by a spark plug (which is common for gasoline/petrol engines) or by compression ignition (which is common for diesel engines). However, it is to be appreciated that other forms of variations of ignition, or aids to ignition, may be used including glow plugs.

[0087] Fig. 1 illustrates a single piston 115 of the engine 2. However, it is to be appreciated that the engine 2 may have more than one cylinder 15 and piston 115 combination. For example, the engine 2 may have two cylinders, four cylinders, five cylinders, six cylinders, eight cylinders, ten cylinders, twelve cylinders, etc. It is to be appreciated that the air intake 1 may be used in different configurations of engines 2, such as inline cylinders, "V"

configuration cylinders, flat configuration (boxer configuration), "W" configuration engine, radial engines, etc.

[0088] It is to be appreciated that the air intake 1 described herein may be adapted for use in two-stroke engines. In other examples, the air intake 1 may be used to supply air, or fuel air mixture, to a combustion chamber of a rotary engine (also called "wankel engine" after the inventor Felix Wankel). Processing device

[0089] Fig. 10 illustrates a schematic example of a processing device. The processing device may be in the form of a computer. The processing device may be used as part of the controller (21) that receives sensor signals from sensors and sends control signals to the regulator actuators (22). The processing device includes a processor (1310), a memory (1320) and an interface device (1340) that communicates with each other via a bus (1330). The memory (1320) stores instructions and data for implementing the method (300) described above, and the processor (1310) performs the instructions from the memory (1320) to implement the method (300). The interface device (1340) facilitates communication other peripherals, such as the sensor(s) and actuator(s) (22). In some examples, the interface device (1340) allows communication with a user interface and/or with other processing devices networked with the processing device. It should be noted that although the processing device may be independent, functions performed by the processing device may be distributed between multiple network elements.

[0090] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. An air intake (1) for an internal combustion (2) comprising:

- at least one runner (3) wherein the runner (3) includes an inlet (5) fluidly connected to an outlet (7), wherein the runner (3) provides a passage (9) for air (11), or fuel air mixture, to a respective intake port (13) of a combustion chamber (14); and

- a regulator (17) to vary an effective cross-section (19) of a portion (20) of the runner (3), such that during intake a velocity of air to the intake port (13) is substantially consistent throughout an operating revolution range and the regulator (17) varies the effective cross-section (19) to adjust an air flow rate to the combustion chamber (14).

2. An air intake (1) according to any one of the preceding claims further comprising:

- a regulator actuator (22) to operate the regulator (17); and

- a regulator controller (21) to control operation of the regulator actuator (22), wherein the regulator controller (21) is operable based on one or more control parameters.

3. An air intake (1) according to claim 2 wherein the one or more control parameters comprise an engine speed.

4. An air intake (1) according to either claim 2 or 3 wherein the one or more control parameters comprise valve timing, and wherein the regulator controller controls operation of the regulator actuator such that peak pressure at the intake port (13) corresponds to closing of an intake valve (124).

5. An air intake (1) according to any one of claims 2 to 4 wherein the one or more control parameters comprise a fuel throttle setting.

6. An air intake (1) according to any one of claims 2 to 5 wherein the one or more control parameters comprise an air temperature.

7. An air intake (1) according to any one of claims 2 to 6 wherein the one or more control parameters comprise an induction air pressure.

8. An air intake (1) according to any one of the preceding claims wherein the portion (20) of the runner (3) includes an aperture (23) and the regulator (17) includes a plug (25), wherein the plug (25) is displaceable through the aperture (23) to vary the effective cross- section (19) of the portion (20).

9. An air intake (1) according to claim 8 wherein aperture (23) includes a substantially circular cross-section.

10. An intake (1) according to either claim 8 or 9 wherein at least part of the aperture (23) includes an inner wall portion with a frustoconical surface.

11. An intake (1) according to any one of claims 8 to 10 wherein the plug (25) includes an outer surface portion that has a frustoconical surface.

12. An intake (1) according to any one of the preceding claims for an internal combustion engine having a plurality of cylinders (15) with respective combustion chambers (14) wherein the air intake (1) comprises a plurality of runners (3) each associated with a respective combustion chamber (14).

13. An air intake (1) according to claim 12 wherein the intake further comprises a plenum housing (27), wherein the inlet (5) of the at least one runner (5) is fluidly connected to a chamber (29) of the plenum housing (27), and wherein the plenum (27) supplies the air or an fuel air mixture.

14. An air intake (1) according to claim 12 or 13 wherein the runners (3) have respective regulators (17) and where one or more regulators (17) are synchronised to one another.

15. An air intake (1) according to claim 14, wherein the one or more regulators (17) are synchronised with each other via a regulator cam shaft (30).

16. An air intake (1) according to claim 15 wherein a common regulator actuator (31) operates the regulator cam shaft (30).

17. An air intake for an internal combustion engine according to any one of the preceding claims wherein the engine is a reciprocating piston engine.

18. An air intake for an internal combustion engine according to any one of claims 1 to 16 wherein the engine is a wankel rotary engine.

19. An internal combustion engine including the air intake according to any one of claims 1 to 18.

20. A method (300) of introducing air from an air intake (1) to an internal combustion engine (2) at a desired velocity, the method comprising:

- determining (310) the desired velocity of air for the internal combustion engine;

- determining (320), based on at least one control parameter, a desired air flow rate for the engine (2);

- calculating (330) a desired effective cross-section for a runner of the air intake (1), based on the desired velocity of air and the desired air flow rate; and

- sending (340), to a regulator actuator (22), a control signal to actuate a regulator (17) to vary an effective cross-section (19) of the runner (3) to the calculated desired effective cross-section.

21. A method (300) according to claim 20 wherein the control parameter comprises one or more of:

- an engine speed;

- valve timing;

- a fuel throttle setting;

- air temperature; and - induction air pressure.

22. A method according to claim 21 further comprising calculating a desired effective cross-section for a runner (3) such that the timing of peak pressure at an intake port (13) corresponds to closing of an intake valve (124).