Patent Grant
9410525
The present disclosure relates to valve controlled combustion systems.
This section provides background information related to the present disclosure, which is not necessarily prior art.
Internal combustion engines (“ICEs”) typically include a combustion chamber, an intake and exhaust port, a compression device, a fuel delivery system, and an ignition device. ICEs place the ignition device into constant contact with the combustible mixture of air and fuel and control the ignition of that mixture by intermittent activation of the ignition device. For example, intermittent operation of a spark plug, activated by a high voltage pulse to produce a plasma flame kernel. However, in order to achieve higher fuel efficiency, the compression ratios of ICEs are growing higher, and the air-fuel mixtures are becoming leaner. This requires ignition devices such as spark plugs to use higher voltages for consistent combustion.
Furthermore, the ignition devices are exposed to the high ranges of pressures, temperatures, and chemical mixtures that exist in the combustion chamber during the entire engine cycle. This exposure can lead to degradation of the ignition device, including buildup of soot, which can result in inconsistent combustion and loss of fuel economy and power. Additionally, ignition devices in ICEs utilizing compressed natural gas (“CNG”) as the fuel tend to build up soot more quickly than ICEs operating on traditional fuels, such as gasoline, for example. This additional buildup can require more frequent maintenance, often making CNG ICEs impractical or too costly for certain applications.
The geometry and operation of sparkplugs also makes controlling the propagation of the flame front difficult. This can lead to premature flameout resulting in inconsistent combustion, and loss of fuel economy and power.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
The present teachings provide for an internal combustion engine combustion system, including an ignition element and an ignition actuation member. The ignition element is configured to ignite an air-fuel mixture compressed within a combustion chamber of an internal combustion engine. The ignition actuation member is movable between a first position in which the ignition actuation member prevents ignition of the air-fuel mixture when present in the combustion chamber, and a second position in which the ignition actuation member permits ignition of the air-fuel mixture by exposing the ignition element to the air-fuel mixture when the air-fuel mixture is present in the combustion chamber.
The present teachings also provide for an internal combustion engine combustion system, including an ignition surface, an ignition actuation member, an isolation cavity, an isolation member, and an actuating device. The ignition surface is configured to be heated to a temperature sufficient to create an ignition element to ignite an air-fuel mixture compressed within a combustion chamber of the internal combustion engine. The ignition actuation member is movable between a first position in which the ignition actuation member prevents ignition of the air-fuel mixture when present in the combustion chamber, and a second position in which the actuation member permits ignition of the air-fuel mixture by exposing the ignition element to the air-fuel mixture when the air-fuel mixture is present in the combustion chamber. The isolation member seals the ignition surface within the isolation cavity in the first position. The actuating device is configured to move the ignition actuation member between the first and second positions.
The present teachings further provide for a method of operating an internal combustion engine. The method includes moving an ignition actuation member from a first position, in which the ignition actuation member prevents ignition of an air-fuel mixture present in a combustion chamber of an internal combustion engine by preventing exposure of an ignition element to the air-fuel mixture therein, to a second position in which the ignition actuation member permits ignition of the air-fuel mixture by permitting exposure of the ignition element to the air-fuel mixture, and returning the ignition actuation member to the first position after ignition of at least a portion of the air-fuel mixture.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
The present teachings are directed to a combustion system and method for use in an internal combustion engine (“ICE”). The ICE can be of any type, such as a piston-cylinder engine or a Wankel engine, for example. The ICE may be located within a vehicle, such as an automobile, truck, machinery, aircraft, watercraft, or any other vehicle to provide power for locomotion, for example. However, it is also contemplated that the ICE could be used in other applications with or without a vehicle such as an electrical generator or to operate machinery, for example.
The compression device 14 can include a piston 24 coupled to a piston rod 26 disposed within a cylinder 28, such as that illustrated in
The combustion chamber 16 is configured to contain an air-fuel mixture under compression by the compression device 14. The combustion chamber 16 is further configured to contain the combustion of the air-fuel mixture when the air-fuel mixture is ignited by the ignition element 22a.
The ignition device 22 can be a typical spark plug and the ignition element 22a can be a spark generated to ignite the air-fuel mixture. The ignition device 22 can also be a geometric shape, such as a ring, toroid, plate, cylinder, sphere, or any other geometry, and the ignition element 22a can be the surface of ignition device 22 and be configured to be heated to a temperature sufficient to ignite the air-fuel mixture within the combustion chamber. The ignition element 22a can be heated, for example, by electrical resistance, infrared, laser, or induction heating. The ignition device 22 can alternatively be configured to emit the ignition element 22a as radiation, such as infrared, or laser radiation for example, the radiation configured to ignite the air-fuel mixture within the combustion chamber. When the ignition device 22 is operated by an electrically powered means, the combustion system can be connected to a power source 66, such as a battery, an alternator, or a power grid, for example. The shape of the ignition element 22a can be configured to control the propagation of a flame front during combustion to ensure more complete combustion within the combustion chamber 16.
During the typical operation of a piston-cylinder type ICE 12, the compression device 14 compresses the air-fuel mixture within the combustion chamber 16 during a compression stroke of the piston 24. During the compression stroke, the volume of the combustion chamber 16 is decreased, causing the pressure of the air-fuel mixture to increase. At or near a combustion pressure, the ignition element 22a ignites the air-fuel mixture. The ignition of the air-fuel mixture can start with a plasma flame kernel originating at the ignition element 22a. The combustion of the air-fuel can propagate from the ignition element 22a through the air-fuel mixture in the combustion chamber 16 by the flame front. The combustion of the air-fuel mixture forces the piston 24 to begin a power stroke, in which the volume of the combustion chamber 16 increases, and the piston 24 performs work, such as linear motion from the piston 24, rotation of a crankshaft (not shown), or rotation of a rotor of an electrical generator (not shown), for example.
The intake port 18 can include an intake valve 30. The intake valve 30 can be configured to move between an open position and a closed position to selectively allow air to pass through the intake port 18 and enter the combustion chamber 16 when the intake valve 30 is in the open position. The air-fuel mixture for combustion can be created by mixing fuel with air before the air enters the combustion chamber 16. Alternatively, fuel can be injected separately into the combustion chamber 16 and allowed to mix with the air in the combustion chamber 16 to create the air-fuel mixture therein. The fuel can enter the combustion chamber separately through a fuel injector (not shown). The fuel can be any type of fuel used in ICEs, such as gasoline, diesel, bio-diesel, natural gas, ethanol, or any other type of fuel, or blend of fuels.
When the intake valve 30 is in the closed position, the intake valve 30 prevents the air-fuel mixture from passing through the intake port 18. During the typical operation of a piston-cylinder type ICE 12, the intake valve 30 will generally be in the open position during an intake stroke of the piston 24. The intake valve 30 would generally be in the closed position during compression, power, and exhaust strokes of the piston 24. However, it is known that variations on the timing of opening or closing the intake valve 30 may be used.
The exhaust port 20 can include an exhaust valve 32. The exhaust valve 32 can be configured to move between an open position and a closed position to selectively allow combustion gases, along with any uncombusted air and fuel, to pass through the exhaust port 20 and exit the combustion chamber 16 when the exhaust valve 32 is in the open position. During the typical operation of a piston-cylinder type ICE 12, the exhaust valve 32 will generally be in the open position during an exhaust stroke of the piston 24. The exhaust valve 32 would generally be in the closed position during intake, compression, and power strokes of the piston 24. However, it is known that variations in the timing of opening or closing the exhaust valve 32 may be used.
An ignition actuation member 34 can selectively isolate the ignition element 22a from communication with the combustion chamber 16 in a first position, and selectively allow communication between the ignition element 22a and the combustion chamber 16 in a second position. The ignition actuation member 34 can be actuated between the first and second positions by an actuation device 68. The actuation device 68 can be any electrical, mechanical, or electro-mechanical means, such as a solenoid, or cam and follower, for example. The ignition actuation member 34 can be moved from the first position to the second position when the air-fuel mixture is compressed at or near a combustion pressure. The actuation of the ignition actuation member 34 from the first position to the second position exposes the ignition element 22a to the air-fuel mixture and ignites the air-fuel mixture, causing combustion within the combustion chamber 16. The actuation of the ignition actuation member 34 can be controlled to expose the ignition element 22a at a desired time before, during or after full compression of the air-fuel mixture, in the case of a piston-cylinder engine, top-dead center. The ignition actuation member 34 can be returned to the first position after the air-fuel mixture begins combustion. When in the first position, the ignition element 22a is protected from the combustion products. The ignition actuation member 34 can be returned to the first position before the combusted air-fuel mixture is expelled from the combustion chamber 16 during the exhaust stroke. The ignition actuation member 34 can further be returned to the first position before the combustion event, or power stroke is complete.
With reference to
The housing portion 54 can house an actuating device 60. The actuating device 60 can selectively move the ignition actuation member 34 between the first and second positions. The actuation device 60 can be any type of mechanical, electrical, or electro-mechanical device capable of selectively moving the ignition actuation member 34, such as a solenoid, for example. While in the first position, the ignition element 22a is within the isolation cavity 36. The ignition element 22a is coupled to the ignition actuation member 34, and when the ignition actuation member 34 is in the second position, the ignition element 22a is moved into the combustion chamber 16 by the ignition actuation member 34. The ignition element 22a may be fixed to the ignition actuation member 34 by any fastening means such as bolts, screws, adhesives, press or interference fit, or pins, for example.
The connecting portion 56 can couple the main body 52 to the ICE 12, and can include a series of threads 62 configured to mesh with a series of mating threads 64 located on the ICE 12, for example. The series of threads 62 and series of mating threads 64 can allow the main body 52 to be removably coupled to the ICE 12.
The protective tip 58 can isolate the ignition element 22a from the combustion chamber 16 when the ignition actuation member 34 is in the first position. The protective tip 58 protects the ignition element from exposure to conditions within the combustion chamber 16 while preventing the ignition element 22 from igniting the air-fuel mixture prematurely.
The ignition device 22 is attached to the ignition actuation member 34. When the ignition actuation member 34 is in the first position, the ignition device 22 is away from the combustion chamber 16, minimizing exposure of the ignition element 22a to the air-fuel mixture within the combustion chamber 16. When the ignition actuation member 34 is in the second position, the ignition device 22 is closer to the combustion chamber 16, increasing exposure of the ignition element 22a to the air-fuel mixture within the combustion chamber 16. When in the first position, the ignition element 22a penetrating the isolation member 70 is insufficient to ignite the air-fuel mixture within the combustion chamber 16. When in the second position, the ignition element 22a penetrating the isolation member 70 is sufficient to ignite the air-fuel mixture within the combustion chamber 16.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
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