Patent Application
20200116112
The present invention relates to techniques for reducing air velocity fluctuations at mass air flow sensors in a multi-throttle internal combustion engine.
Mass air flow (MAF) sensors are used in internal combustion engines to determine the mass of air passing through the throttle and into the air intake manifold for distribution to the cylinders of the engine. Using this air mass data, the engine controller is able to determine the appropriate amount of fuel to deliver to each cylinder for the desired engine power performance and emissions control.
In a multi-throttle engine having two banks of engine cylinders, such as a V-8 engine having two banks for four cylinders each, separate throttles are used for each bank with separate MAF sensors being used to detect the amount of air flowing through each throttle. To reduce air velocity and pressure variations at the MAF sensor, a honeycomb or other screen is often inserted in the airflow path at the MAF sensor to smooth out or straighten the air velocity and pressure fluctuations. However, these flow screens create a restriction that may undesirably reduce airflow to the intake manifold.
According to one aspect of the invention, there is provided an airflow modifier device for reducing air velocity fluctuations in a multi-throttle internal combustion engine. The airflow modifier device includes:
According to various embodiments, the airflow modifier device may further include any one of the following features or any technically-feasible combination of some or all of these features:
According to another aspect of the invention, there is provided a multi-throttle intake air system for an internal combustion engine. The intake air system includes:
According to various embodiments, the intake air system of the preceding paragraph may further include any one of the following features or any technically-feasible combination of some or all of these features:
According to another aspect of the invention, there is provided a multi-throttle internal combustion engine that includes:
According to various embodiments, the multi-throttle internal combustion engine of the preceding paragraph may further include any one of the following features or any technically-feasible combination of some or all of these features:
One or more embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein:
Described below and shown in the accompanying drawings is an embodiment of an airflow modifier device, a multi-throttle air intake system that incorporates the air modifier device, and an internal combustion engine that includes the multi-throttle air intake system. In general, the airflow modifier device provides a cross-over communication channel or passageway that permits at least partial mixing of the separate intake airstreams being supplied to separate cylinder banks of the engine. This cross-over communication between the airflows permits movement of air between the two intake airstreams in response to differential pressures in the airstreams, thereby enabling those pressure differences to be reduced and thereby reducing the associated velocity fluctuations.
There are a number of advantages to achieving these reduced velocity and pressure fluctuations during engine cycles, including improving the usability of the data received from the intake airflow sensors in the engine without the use of flow screens and, in at least some embodiments, permitting the use of simpler airflow sensors, simpler airflow sensor signal filtering, elimination of flow screens, and more options for sensor placement in the intake air system.
Referring to
The engine 10 includes a multi-throttle intake air system 16 that includes first and second air intake channels 18, 19 that receive respective first and second airflows 20, 21. Each channel 18, 19 includes, respectively, an intake air duct 30, 31, an airflow sensor 32, 33, a throttle 40, 41, and an air intake manifold 50, 51. The intake air system 16 further includes an airflow modifier device 60 which forms a portion of both air intake channels 18, 19 and that is located between the throttles 40, 41 and their respective intake manifolds 50, 51. In general, the airflows 20, 21 enter their associated intake air duct 30, 31, flow past the respective sensors 32, 33, into their associated throttles 40, 41, through the airflow modifier device 60, and into their associated air intake manifolds 50, 51 where they are passed to different ones of the cylinders 14 at different points in the engine cycle. For this, each of the cylinders 14 of the first cylinder bank 12 are connected to receive air from one of the manifold output ports of the first air intake manifold 50, and each of the cylinders 14 of the second cylinder bank 13 are connected to receive air from one of the manifold output ports of the second air intake manifold 51.
The airflow sensors may be mass air flow (MAF) sensors that measure the amount of air moving through the passageways of the respective first and second intake air ducts 30, 31. In other embodiments, other types of mass, velocity, or other suitable airflow sensors may be used.
The volumetric flow through each throttle 40, 41 is controlled by respective throttle control members 42, 43 in accordance with various inputs including, in particular, the driver torque demand as determined by accelerator pedal position. The construction and operation of the throttles 40, 41 and their control members 42, 43 may be conventional and will be known to those skilled in the art.
In the description that follows, the details of only the components of first air intake channel 18 are identified and described, and the construction and operation of the second air intake channel 19 may be identical or at least similar to that of air intake channel 18. In
For the first air intake channel 18, each of the illustrated airflow components 30, 40, 50, 60 has an input port, output port, and passageway connecting the input and output ports in fluidic communication so that the airstreams can flow through them to deliver air to the engine cylinders 14. In particular, intake air duct 30 includes a duct input port 34, a duct output port 36, and a duct passageway 38 connecting the input port 34 and output port 36 so that air flowing into the input port 34 exits the output port 36. Throttle 40 likewise has a throttle input port 44, a throttle output port 46, and a throttle passageway 48. The throttle input port 44 receives the airflow exiting from the output port 36 of its associated intake air duct 30 and that air moving through the passageway 48 then exits the throttle output port 46. Downstream of the throttle 40 is the air intake manifold 50 which has an input port 54 and a plurality of output ports 56 all connected by a common plenum 58. The manifold input port 54 of the air intake manifold 50 receives air exiting the throttle output port 46 of the throttle 40. In the illustrated embodiment, this is done via the airflow modifier device 60 which is located upstream of the intake manifolds 50, 51; specifically, it is located between the throttles 40, 41 and intake manifolds 50, 51 such that air entering the intake manifolds is conveyed to the manifold input ports via at least one of the passageways within the airflow modifier device 60.
Airflow modifier device 60 also has input and output ports for the first and second air intake channels 18, 19, but these are combined into a single body 62 that can be molded, cast, machined, or otherwise formed. The body 62 may be formed as an integral component, such as from two or more pieces joined together, or as a unitary component made from a single, molecularly continuous piece of material. Airflow modifier device 60 has first and second air input ports 64, 65, first and second air output ports 66, 67, and first and second passageways 68, 69 respectively connecting the first air input port 64 with the first air output port 66 and the second air input port 65 with the second air output port 67. The airflow modifier device 60 further includes a central passageway 70 interconnecting the first and second passageways 68, 69 so that air entering the first and second air input ports 64, 65 can move between the first and second passageways 68, 69. Further details of the construction and operation of airflow modifier device 60 are described farther below.
In general, the airflow modifier device 60 is located between the intake air ducts 30, 31 and the intake manifolds 50, 51 such that air exiting the duct output ports is conveyed to the manifold input ports via at least one of the passageways 68-70 of the airflow modifier device. For example, this can be by air flowing through the device 60 via passageway 68 only, such that the same air entering input port 64 exits through output port 66. Alternatively, because the first and second channel passageways 68, 69 are interconnected by the cross-passageway 70, then some of the air exiting the output port 66 could come from input port 64 and some could come from input port 65 by flowing through a portion of passageway 69, then through passageway 70, to the passageway 68 where it joins the air that entered through input port 64, all of which then exits through output port 66. Or, air entering a single input port (64 or 65) may split with different portions exiting through both output ports 66, 67. These different flows may occur due to pressure differences between the passageways 68, 69 during different points in the engine cycle. Other such routing of the air through the device 60 may occur depending upon cylinder/intake plenum pressures and relative throttle positions at different points in the engine cycle. As a result, during at least some portions of the cycles of the engine 10, some of the air entering each of the manifold input ports of the first and second air intake manifolds 50, 51 comes from the airflows passing through the passageways of both the first and second throttles 40, 41.
As a result of this passageway 70, air moving through that passageway between the first and second channels 18, 19 can reduce air flow velocity fluctuations at the flow sensors 32, 33 located in the airflows upstream of the airflow modifier device 60. And, as will be appreciated by those skilled in the art, this may be done without including any flow screens in the airflow sensors 32, 33 or otherwise in the air intake channels 18, 19.
Although the airflow modifier device 60 is depicted in
Referring now to
The body 62 defines the passageways 68-70, with the first air input port 64 and first air output port 66 each comprising tubular extensions of the body 62 that are aligned with each other so as to form the first passageway 68 centered along a first flowpath line 72 extending through the airflow modifier device 60 through center points 76 of the first air input port 64 and first air output port 66, and wherein the second air input port 65 and second air output port 67 each comprise tubular extensions of the body 62 that are aligned with each other so as to form the second passageway 69 centered along a second flowpath line 73 extending through the airflow modifier device 60 through center points 77 of the second air input port 65 and second air output port 67. These flowpath lines 72, 73 may be, but need not be, linear and/or parallel, as shown in the illustrated embodiment. For example, they could be curved such as where the input ports 64, 65 enter at an angle relative to the output ports 66, 67.
The body 62 of the airflow modifier device 60 further includes a lateral plenum 78 that connects the tubular extensions defining the first passageway 68 with the tubular extensions defining the second passageway 69, the lateral plenum 78 being open into the first and second passageways 68, 69 and defining the central passageway 70 that interconnects the first and second passageways. The central passageway 70 extends along a linear third flowpath line 74 that, in the illustrated embodiment, is perpendicular to the first and second flowpath lines 72, 73.
As indicated in the figures, the passageways 68, 69 each have a cross-sectional area A that is equal to each other. For the circular input and output ports 64-67 having a common radius r, the area A is equal to π2 and this can be sized to be equal to the cross-section passageway areas of the ports of one or more of the other airflow system components 30, 40, 50, or as otherwise desired or appropriate for the particular engine application.
The central passageway 70 has a cross-section area B that, for the generally rectangular cross-section shown, is equal the width w times the height h of the plenum 78. That area B may take on different sizes depending on the application, but at sizes much less than 50% of the area A the amount of velocity fluctuation smoothing is reduced and, at sizes greater than 150% there is no apparent increase in velocity fluctuation smoothing. Thus, in at least some embodiments the cross-sectional area B is at least 50% and not more than 150% of the cross-sectional area A, and in some more specific embodiments, is not more than 100% of the cross-sectional area A.
It is to be understood that the foregoing is a description of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. For example, although the airflow modifier device may be particularly advantageous when used with a MAF sensor, it may also be used in conjunction with other types of air flow sensors such as a manifold absolute pressure (MAP) sensor, or in systems that use both MAF and MAP sensors. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.
As used in this specification and claims, the terms “e.g.,” “for example,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. In addition, the term “and/or” is to be construed as an inclusive OR. Therefore, for example, the phrase “A, B, and/or C” is to be interpreted as covering all of the following: “A”; “B”; “C”; “A and B”; “A and C”; “B and C”; and “A, B, and C.”
