WO2015057952A1

WO2015057952A1 - Multi-stage swirl induction apparatus and method

Info

Publication number: WO2015057952A1
Application number: PCT/US2014/060881
Authority: WO
Inventors: Matt Rasmussen
Original assignee: Erik Buell Racing, Llc
Priority date: 2013-10-16
Filing date: 2014-10-16
Publication date: 2015-04-23

Abstract

Provided is an internal combustion engine adapted for swirl induction having a manifold adapted to output a first fluid, a combustion cylinder adapted to receive the first fluid, first and second intake valves, and a bypass air port. The first intake valve is adapted to selectably permit fluid communication of the first fluid from the manifold, through the first intake valve, and into the combustion cylinder along a first flow stream and has a first valve opening profile. The second intake valve is adapted to selectably permit fluid communication of the first fluid from the manifold, through the second intake valve, and into the combustion cylinder along a second flow stream and has a second valve opening profile different from the first valve opening profile. The bypass air port may be proximate to the first intake valve and offset in the first flow stream.

Description

MULTI-STAGE SWIRL INDUCTION APPARATUS AND METHOD

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 61/891,704, filed October 16, 2013 the disclosure of which is incorporated here by reference.

BACKGROUND AND SUMMARY

[0002] The present subject matter relates to internal combustion engines. More specifically the present subject matter relates to a method and apparatus for intake and combustion of fuel in an internal combustion engine.

[0003] In internal combustion engines, a focus has been improvement of combustion efficiency of fuel in air mixtures to reduce fuel consumption and reduce pollution emissions. The internal combustion used in internal combustion engines is complex and difficult to do correctly, with changing chamber shape and changing compression ratio. Combustion of a fuel-air mixture is more efficient and complete if the fuel-air mixture is well mixed, and turbulent flow, such as produced by swirling or tumbling action, is known to promote mixture of an fuel-air mixture. Application of low swirl combustion, swirling the fuel-air mixture prior to combustion, in internal combustion engines for motor vehicles has been known but previously available systems have not been effective.

[0004] One approach at swirl flow in internal combustion utilized a shroud around the intake valve, to purposely introduce turbulence by swirling the incoming fuel-air mixture, with a modified wedge shaped combustion chamber adapted to direct the incoming fuel-air mixture toward a centrally mounted spark plug. This approach was limited and undesirable in that it was adapted for application only in a two valve cylinder head with a single intake valve offset from the cylinder centerline. Other attempts to provide swirl and better combustion have also had problems. Modified piston tops and other such designs to mechanically force swirl to occur do not provide high output per engine cc, as the combustion chamber shape is compromised, causing poor airflow at peak output and/or hot spots due to odd geometry that cause pre-ignition, as well as adding piston mass that limits engine speed and thus the power capability.

[0005] Four and three valve engines have in the past provided the high performing combustion chamber with large valve area for high combustion chamber fill, light weight valves for high rpm valve stability, and an efficient combustion chamber shape for power. However, as conventional four and three valve engines have symmetrical intake valves; they do not produce a swirl motion by an internal combustion engine, such as a two valve engine, in which the intake valve is offset from the piston centerline.

[0006] Another approach has proposed tumble motion instead of swirl motion in the cylinder heads for efficient combustion. However, tumbling does not produce the same results as a swirl motion. High performance engines generally require combustion chambers that are flat and wide, suppressing a tumble motion as the piston moves up during the compression cycle. The other approach to provide a swirl motion in a four valve cylinder head have involved distorted combustion chambers, which cause known problems.

[0007] In high RPM/high performance engines with four valve cylinder heads, combustion has often suffered from aggressive tuning, high overlap valve lift profiles, and flat wide combustion chambers from over-square bore to stroke ratios, all of which are desirable for efficient power output. Poor combustion is often directly measureable by long combustion mixture burn duration and reduced combustion stability. Combustion stability may also cause poor drivability from inconsistent torque pulses delivered, and create less than efficient tail pipe emissions. Long burn duration causes poor thermal efficiency, conversion of a fuel- air mixture into useful torque, and thus also results in high engine related temperatures. Accordingly, a very desirable engine design configuration, one that produces the highest peak power output efficiency per cc is plagued by poor fuel economy, poor drivability, poor lower rpm power and overheating when not operating at peak output. Therefore, there remains a need for an apparatus and method to provide an internal combustion engine with desirable turbulent combustion flow, while avoiding problems encountered in previous approaches.

[0008] Presently disclosed is a system that includes a manifold adapted to deliver a first fluid, a combustion cylinder adapted to receive the first fluid from the manifold along a first flow stream through a first intake valve having a first opening profile, and a second flow stream through a second intake valve having a second opening profile, in which the second opening profile differs from the first opening profile.

[0009] Also disclosed is a method that includes introducing a first fluid into a combustion cylinder from a manifold along a first flow stream through a first intake valve responsive to a first opening profile, and introducing a second fluid into the combustion cylinder from the manifold along a second flow stream through a second intake valve responsive to a second opening profile, in which the second opening profile is different from the first opening profile to create a swirled flow within the combustion cylinder. [0010] In some embodiments, the first opening profile defines lift for the first intake valve, and the second opening profile defines lift for the second intake valve. In some embodiments, the first intake valve is positioned so that flow of the first fluid along the first flow stream is a positive function of the lift of the first intake valve; and the second intake valve is positioned so that flow of the first fluid along the second flow stream is a positive function of the lift of the first intake valve. In some embodiments, at least one of the lift of the first intake valve and the lift of the second intake valve is selectably variable. In some embodiments, at least one of the lift of the first intake valve and the lift of the second intake valve is controllable. In some embodiments, at least one of the lift of the first intake valve and the lift of the second intake valve is controlled by an actuator. In some embodiments, the actuator is mechanical, electronic, or hydraulic. In some embodiments, the first opening profile defines the first valve lift as a function of a crank angle; the second opening profile defines the second valve lift as a function of the crank angle; and at least part of the first opening profile is offset from the second opening profile by an offset crank angle. In some embodiments, the first opening profile defines the first valve lift as a function of a crank angle; the second opening profile defines the second valve lift as a function of the crank angle; and at least part of the first opening profile is offset from the second opening profile by an offset valve lift.

[0011] In some embodiments, the system further includes a bypass air port offset in the first flow stream and proximate to the first intake valve. In some embodiments, the system further includes a bypass air valve configured to control a bypass airflow through the bypass air port.

[0012] In some embodiments, the method further includes introducing a bypass airflow in the first flow stream through the first intake valve. In some embodiments, the method further includes controlling the bypass airflow with a bypass air valve in a bypass air port. In some embodiments, the method further includes opening the first valve at a first crank angle; and opening the second valve at a second crank angle, where the first crank angle is different from the second crank angle. In some embodiments, the method further includes opening the first valve by a first lift amount at a first crank angle; and opening the second valve by a second lift amount at the first crank angle, where the first lift amount is different from the second lift amount.

[0013] Also disclosed is a system that includes a manifold adapted to deliver a first fluid, a combustion cylinder adapted to receive the first fluid from the manifold along a first flow stream through a first intake valve having a first opening profile, and a second flow stream through a second intake valve having a second opening profile, and a bypass air port offset in the first flow stream, and proximate to the first intake valve. In some embodiments, the second opening profile differs from the first opening profile; the first opening profile defines lift for the first intake valve, and the second opening profile defines lift for the second intake valve; the first intake valve is positioned so that flow of the first fluid along the first flow stream is a positive function of the lift of the first intake valve, and the second intake valve is positioned so that flow of the first fluid along the second flow stream is a positive function of the lift of the first intake valve; and the first opening profile defines the first valve lift as a function of a crank angle, the second opening profile defines the second valve lift as a function of the crank angle, and

at least part of the first opening profile is offset from the second opening profile by an offset crank angle or an offset valve lift. In some embodiments, the lift of the first intake valve and the lift of the second intake valve are each controllable by a mechanical, electronic, or hydraulic actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Reference is made to the accompanying drawings in which particular embodiments and further benefits of the subject matter are illustrated as described in more detail in the description below, in which:

[0015] FIG. 1A is a top cylinder head view showing a first embodiment of a swirl induction apparatus.

[0016] FIG. IB is a cross-section of showing the first embodiment of a swirl induction apparatus.

[0017] FIG. 1C is a cut away view showing the first embodiment of a swirl induction apparatus.

[0018] FIG. ID is another cut away view showing the first embodiment of a swirl induction apparatus.

[0019] FIG. 2 is a graph showing the valve lift as a function of crank angle for each of the two valves in the first embodiment of a swirl induction apparatus.

[0020] FIG. 3 is a schematic illustration of a combustion cylinder with two flow streams.

[0021] FIG. 4 is a side view of a motorcycle in accordance with the present disclosure. DETAILED DESCRIPTION

[0022] Disclosed is an apparatus and method for an internal combustion engine with swirl induction in one or more combustion chambers. The presently disclosed subject matter includes a two stage approach of staggered intake cams and an offset bypass air port to induce a swirling mixture motion that creates improved air and fuel mixture as well as high turbulence through the point of ignition and establishment of a flame front. This apparatus and method improves combustion stability and reduces burn duration, and may also improve one or more of drivability of the vehicle, tail-pipe emissions, and performance, and reduce engine temperatures.

[0023] As used herein unless otherwise noted, tumble motion is combustion intake flow around an axis substantially perpendicular to the direction of piston reciprocation. As used herein, swirl motion is combustion intake flow around an axis substantially parallel to the direction of piston reciprocation. It should be understood that a combustion flow can both tumble and swirl simultaneously.

[0024] A multi-stage swirl induction method and apparatus are provided. Lower level stages are adapted for low throttle openings and high manifold vacuum where the induced fresh air mass is low. Lower level stages are accomplished by a bypass air port 150 that is offset in the first flow stream 172 and very close to the intake valves 140. This offset in the first flow stream 172 causes an imbalance in flow through the two intake valves 140, creating a pressure differential behind the intake valves 140 inside the combustion cylinder 130, which causes a swirl motion as the flowing fluid flows from higher pressure to lower pressure regions. Higher stages become more effective as the throttle or other governor opens, creating more air mass flow through the intake valves 140, and the manifold 120 vacuum decreases. A high manifold vacuum causes more and more air flow through the bypass port 150.

[0025] In some embodiments, higher stages may be accomplished with fixed offset intake valve opening profiles 243, 245. When the intake stroke is occurring and the air mass flowing into the combustion cylinder 130 is sufficient, a difference in the lift of the intake valves 140 causes a flow difference across the two valves 140, which induces a swirl motion. Any or all of the design of the intake runner for the engine's cylinder head, the shape of the piston, the level of valve lift offset, and the tune/adjustment for the amount of air flowing through the bypass port may be engineered or optimized for a given engine configuration.

[0026] Referring now to FIGS. 1-3, an embodiment of an apparatus for promotion of swirl motion induction 100 is illustrated. The embodiment of the apparatus for promotion of swirl induction 100 shown in FIGS. 1A-1D is engaged with an associated internal combustion engine 90. The combined system 110 of the apparatus for promotion of swirl induction 100 and the engine 90 includes a manifold 120, a combustion cylinder 130, and a set of intake valves 140. The combined system 110 may further include a bypass air port 150. The combined system 110 may further include various conventional engine components 160.

[0027] In various embodiments, the manifold 120 is an intake manifold adapted to output a fluid 163. The fluid 163 may be air or a fuel-air mixture. The fluid 163 may be delivered to the manifold 120 or may be mixed within the manifold 120 from a plurality of components such as, without limitation, fuel and air. The manifold 120 is in fluid communication with, and be adapted to output the fluid 163 to a combustion cylinder 130, or both combustion cylinder 130 and an intake port 162.

[0028] The combustion cylinder 130 is adapted to receive the first fluid 163. The combustion cylinder 130 is in fluid communication with and adapted to intake fluid 163 from manifold 120, or both manifold 120 and intake port 162. In embodiments, the combustion cylinder 130 is a cylinder for a reciprocating internal combustion engine 90, which may be, for example, a Diesel engine or a Otto Cycle engine.

[0029] In embodiments, the apparatus for promotion of swirl induction 100 includes a plural number of intake valves 140. In the embodiment shown in FIGS. 1A-1D, the apparatus for promotion of swirl induction 100 has two intake valves 140: a first intake valve 142, and a second intake valve 144. Fluid communication between the combustion cylinder and the manifold 120 is selectably permitted by the intake valves 140.

[0030] The first intake valve 142, or any other intake valve 140, may be opened and closed to control the flow into the combustion cylinder. In various embodiments, the opening and closing of first intake valve 142, or any other intake valve 140, is controlled mechanically, electronically, or hydraulically. In the embodiment shown in FIGS. 1A-1D, the first intake valve 142 is opened by an amount described as valve lift. Valve lift may be measured in units of length. The first intake valve 142 is adapted to selectably permit fluid communication of the first fluid 163 from the manifold 120, through the first intake valve 142, and into the combustion cylinder 130 along a first flow stream 172. Flow of the first fluid 163 from the manifold 120, through the first intake valve 142, and into the combustion cylinder 130 along a first flow stream 172 is permitted when the first intake valve 142 is open and is not permitted when the first intake valve 142 is closed. [0031] In a similar manner, the second intake valve 144, or any other intake valve 140, may be opened and closed. In various embodiments, the opening and closing of second intake valve 144, or any other intake valve 140, is controlled mechanically, electronically, or hydraulically. Referring to FIGS. 1A-1D, the second intake valve 144 is opened by an amount described as valve lift. Valve lift may be measured in units of length. The second intake valve 144 is adapted to selectably permit fluid communication of the first fluid 163 from the manifold 120, through the second intake valve 144, and into the combustion cylinder 130 along a second flow stream 174. Flow of the first fluid 163 from the manifold 120, through the second intake valve 144, and into the combustion cylinder 130 along a second flow stream 174 is permitted when the second intake valve 144 is open and is not permitted when the second intake valve 144 is closed.

[0032] The opening and closing of each of the intake valves 142, 144, is referred to as the valve opening profile 243, 245 for that particular valve. In some embodiments, the first intake valve 142 is opened and closed as a function of crank angle. The first valve opening profile 243 for the first intake valve 142, need not be the same as the second valve opening profile 245 for the second intake valve 144. In some embodiments, the first valve opening profile 243 for the first intake valve 142, is offset from the second valve opening profile 245 by an angular phase shift. Referring to FIG. 2, the first valve opening profile 243 is different from the second valve opening profile 245. In some embodiments, both the first intake valve 142 and the second intake valve 144 may be opened and closed as a function of crank angle. In FIG. 2, the first valve opening profile 243 is offset along the crank angle axis from the second valve opening profile 245 by approximately 10 degrees and has a higher peak valve lift. The first valve opening profile 243 shows the first intake valve 142 starts to open at a crank angle of approximately -95 degrees, reaches a peak valve lift of approximately 12.5 mm of lift at a crank angle of approximately 105 degrees, and closes at a crank angle of approximately 310 degrees. The second valve opening profile 245 shows the second intake valve 144 starts to open at a crank angle of approximately -85 degrees, reaches a peak valve lift of approximately 11.5 mm of lift at a crank angle of approximately 110 degrees, and closes at a crank angle of approximately 310 degrees. In some embodiments, the first valve opening profile 243 and the second valve opening profile 245 converge at approximately 180 degrees, such that the first intake valve 142 and the second intake valve 144 close in a generally uniform manner. [0033] The intake valves provide flow that is a positive function of their lift. The more lift an intake valve has, the more flow may pass through the intake valve. As noted above, the opening and closing of second intake valve 144, or any other intake valve 140, may be controlled mechanically, electronically, hydraulic ally, or by other means selected with good engineering judgment. In some embodiments, the lift of one or more valves is selectably variable, such as by selecting from among a predetermined set of lift profiles provided by an actuator, such as replaceable lift cams (not shown), a crank or an electronic actuator. In some embodiments, the lift of one or more valves is controllable. In an embodiment, the lift is controlled by an actuator such as, without limitation, the above noted mechanical, electronic, or hydraulic means. In some embodiments, each valve is independently controlled by a separate actuator to achieved the desired profiles. In other embodiments, the lift of only one valve, such as the second intake valve, is controllable such that the amount of swirl may be varied base upon operating conditions of the engine.

[0034] In some embodiments, a bypass air port 150 is provided that is fluidly engaged with the first intake valve 142 and offset in the first flow stream. The bypass port 150 is adapted to create a flow offset between the first intake valve 142 and the second intake valve 144. In the embodiment shown in FIGS. 1A-1D, the combustion cylinder 130 includes the bypass port 150 formed into the head 164 as part of a fluid passage connected to intake valve 142. The bypass air port 150 is adapted to work alone or in conjunction with the valve lift control for the first intake valve 142 to introduce a flow differential inside the combustion cylinder 130 as air or another fluid, such as a fuel-air mixture enters the combustion cylinder 130. The design of the head 164 of combustion cylinder 130 in conjunction with the flow difference works to create a pressure differential behind the first intake valve 142 that induces a swirl motion clockwise inside the combustion cylinder 130. In some embodiments, the bypass air port 150 is a passive inlet. In other embodiments, the bypass airflow 152 is modulated by an engine control unit. In one embodiment, the bypass airflow 152 through the bypass port 150 is modulated by a bypass control valve (not shown). In various embodiments, the bypass control valve is electronically controlled by a solenoid or by a stepper motor. In some embodiments, control of the bypass control valve permits opening the bypass control valve by selectable amounts to control the bypass airflow 152 velocity. In embodiments in which the bypass air port 150 has the bypass airflow 152 modulated by an engine control unit, the effect of the bypass air port 150 can be tuned specifically for the engine's operating conditions so as to control the air flowing in the bypass port 150 and thereby to affect the amount of swirl generated in the combustion cylinder 130, in a multi-stage manner, tuned/adjusted as appropriate for the particular engine operating mode.

[0035] In embodiments, the system includes engine components 161 such as an intake port 162 for a fluid 163 and an engine cylinder head 164. The fluid 163 may be a fuel-air mixture.

[0036] Referring now to FIG. 3, a schematic illustration of a combustion cylinder with swirl induction is illustrated. As shown in FIG. 3, a combustion cylinder 400 may comprise a piston 410 adapted to reciprocate with respect to the cylinder 400 along the mutual axis 412 of the cylinder 400 and piston 410. A head 440 engaged with the cylinder provides for flow of one or more streams 443, 447 of fluid therethrough and into the cylinder 400 through one or more intake valves 442, 446. As the lift of an intake valves 442, 446 increases, so too increases the flow rate of a streams 443, 447 of fluid therethrough. The intake valves 442, 446 may be opened by different amounts at the same time so that the flow rate of a streams 443, 447 may differ. As shown in FIG. 3, the flow of the stream 443 through intake valve 442 is greater than flow of the stream 447 through intake valve 446. This difference in flow induces a swirl 460 in cylinder 400.

[0037] FIG. 4 illustrates an embodiment of a motorcycle in accordance with the present disclosure.

[0038] It will be appreciated by those of ordinary skill in the art, that various modifications can be made, and that many changes can be made to the disclosed embodiments without departing from the principles of the present subject matter. These and other modifications in the nature of the disclosed embodiments will be apparent to those skilled in the art from the disclosure herein, and it is understood that the foregoing descriptive matter is to be interpreted as illustrative of the present subject matter and not as a limitation.

Claims

What is claimed is:

1. A system comprising:

a manifold adapted to deliver a first fluid;

a combustion cylinder adapted to receive the first fluid from the manifold along

a first flow stream through a first intake valve having a first opening profile, and

a second flow stream through a second intake valve having a second opening profile;

wherein the second opening profile differs from the first opening profile.

2. The system of claim 1, wherein

the first opening profile defines lift for the first intake valve; and

the second opening profile defines lift for the second intake valve.

3. The system of claim 2, wherein

the first intake valve is positioned so that flow of the first fluid along the first flow stream is a positive function of the lift of the first intake valve; and the second intake valve is positioned so that flow of the first fluid along the second flow stream is a positive function of the lift of the first intake valve.

4. The system of claim 3, wherein at least one of the lift of the first intake valve and the lift of the second intake valve is selectably variable.

5. The system of claim 3, wherein at least one of the lift of the first intake valve and the lift of the second intake valve is controllable.

6. The system of claim 5, wherein at least one of the lift of the first intake valve and the lift of the second intake valve is controlled by an actuator.

7. The system of claim 6, wherein the actuator is mechanical, electronic, or hydraulic.

8. The system of claim 3, wherein

the first opening profile defines the first valve lift as a function of a crank angle; the second opening profile defines the second valve lift as a function of the crank angle; and

at least part of the first opening profile is offset from the second opening profile by an offset crank angle.

9. The system of claim 3, wherein

at least part of the first opening profile is offset from the second opening profile by an offset valve lift.

10. The system of claim 1, further comprising:

a bypass air port offset in the first flow stream and proximate to the first intake valve.

11. The system of claim 10, further comprising:

a bypass air valve configured to control a bypass airflow through the bypass air port.

12. A method comprising:

introducing a first fluid into a combustion cylinder from a manifold along a first flow stream through a first intake valve responsive to a first opening profile, and

introducing a second fluid into the combustion cylinder from the manifold along a second flow stream through a second intake valve responsive to a second opening profile, wherein the second opening profile is differs from the first opening profile to create a swirled flow within the combustion cylinder.

13. The method of claim 12, wherein

the first opening profile defines lift for the first intake valve; and

the second opening profile defines lift for the second intake valve.

14. The method of claim 13, wherein

the first intake valve is positioned so that flow of the first fluid along the first flow stream is a positive function of the lift of the first intake valve; and

the second intake valve is positioned so that flow of the first fluid along the second flow stream is a positive function of the lift of the first intake valve.

15. The method of claim 14, wherein at least one of the lift of the first intake valve and the lift of the second intake valve is selectably variable.

16. The method of claim 14, wherein at least one of the lift of the first intake valve and the lift of the second intake valve is controllable.

17. The method of claim 16, wherein at least one of the lift of the first intake valve and the lift of the second intake valve is controlled by an actuator.

18. The method of claim 17, wherein the actuator is mechanical, electronic, or hydraulic.

19. The method of claim 14, wherein

20. The method of claim 14, wherein

21. The method of claim 12, further comprising:

introducing a bypass airflow in the first flow stream through the first intake valve.

The method of claim 21, further comprising:

controlling the bypass airflow with a bypass air valve in a bypass air port.

The method of claim 14, further comprising:

opening the first valve at a first crank angle; and

opening the second valve at a second crank angle, where the first crank angle is different from the second crank angle.

The method of claim 14, further comprising

opening the first valve by a first lift amount at a first crank angle; and

opening the second valve by a second lift amount at the first crank angle, where the first lift amount is different from the second lift amount.

A system comprising:

a manifold adapted to deliver a first fluid;

a second flow stream through a second intake valve having a second opening profile; and

a bypass air port offset in the first flow stream, and proximate to the first intake valve; wherein the second opening profile differs from the first opening profile;

wherein

the first opening profile defines lift for the first intake valve, and

the second opening profile defines lift for the second intake valve;

wherein

the first intake valve is positioned so that flow of the first fluid along the first flow stream is a positive function of the lift of the first intake valve, and the second intake valve is positioned so that flow of the first fluid along the second flow stream is a positive function of the lift of the first intake valve; and

wherein the first opening profile defines the first valve lift as a function of a crank angle;

the second opening profile defines the second valve lift as a function of the crank angle; and

at least part of the first opening profile is offset from the second opening profile by an offset crank angle or an offset valve lift.

26. The system of claim 25, wherein the lift of the first intake valve and the lift of the second intake valve are each controllable by a mechanical, electronic, or hydraulic actuator.