Patent Application
20130061823
The present disclosure relates to engine cylinder bore geometry.
This section provides background information related to the present disclosure which is not necessarily prior art.
Internal combustion engines may combust a mixture of air and fuel in cylinders and thereby produce drive torque. Combustion of the air-fuel mixture produces exhaust gases. Engines may include intake ports to direct air flow to the combustion chambers. Typically, the cylinders have a common spacing along the engine block based on the size of the largest cylinder bore even in arrangements including varying cylinder bore sizes along the length of the engine block.
An engine assembly may include an engine block defining a first cylinder bore, a second cylinder bore directly adjacent to the first cylinder bore and a third cylinder bore directly adjacent to the second cylinder bore. The engine block may define a first distance from a diametrical center of the first cylinder bore to a diametrical center of the second cylinder bore and may define a second distance from the diametrical center of the second cylinder bore to a diametrical center of the third cylinder bore. The first distance may be different than the second distance.
In another arrangement, an engine assembly may include an engine block defining a first cylinder bore and a second cylinder bore directly adjacent to the first cylinder bore. The first cylinder bore may define a first circumference and a first diameter and the second cylinder bore may define a second circumference and a second diameter different than the first diameter. A first radial distance may be defined between a radially outermost point on the first circumference relative to the second cylinder bore and a radially outermost point on the second circumference relative to the first cylinder bore. The first radial distance may be less than 205 percent of the greater of the first and second diameters.
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 and are not intended to limit the scope of the present disclosure in any way.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Examples of the present disclosure will now be described more fully with reference to the accompanying drawings. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
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.
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.
An engine assembly 10 is illustrated in
The air intake assembly 14 may include a first intake air flow path 36 in communication with the first and fourth cylinder bores 24, 30 and the second and third cylinder bores 26, 28. The first intake air flow path 36 may include a first throttle valve 40 and a boost mechanism 41, such as a supercharger. An intake manifold 42 may provide communication between the first intake air flow path 36 and the first and fourth cylinder bores 24, 30. A second intake air flow path 38 may include a second throttle valve 44 and may provide communication between the first intake air flow path 36 and the second and third cylinder bores 26, 28.
The intake ports 32 from the first and fourth cylinder bores 24, may be in communication with the first intake air flow path 36 and the intake ports 32 from the second and third cylinder bores 26, 28 may be in communication with the second intake air flow path 38. The exhaust ports 34 from the first and fourth cylinder bores 24, 30 may be in communication with the exhaust system 16 and the exhaust ports 34 from the second and third cylinder bores 26, 28 may be in communication with the EGR system 18. The EGR system 18 may be in communication with the first intake air flow path 36 and provide communication between the exhaust ports 34 from the second and third cylinder bores 26, 28 and the intake ports 32 from the first and fourth cylinder bores 24, 30. The EGR system 18 may provide communication between the exhaust ports 34 from the second and third cylinder bores 26, 28 and the intake ports 32 from the first and fourth cylinder bores 24, 30 via the intake manifold 42. The EGR system 18 may include an exhaust gas flow path 46 providing communication between the exhaust ports 34 from the second and third cylinder bores 26, 28 and the first intake air flow path 36 and may include an EGR cooler 48.
As seen in
The engine block 20 may define a first distance (D1) from a diametrical center of the first cylinder bore 24 to a diametrical center of the second cylinder bore 26. The engine block 20 may define a second distance (D2) from a diametrical center of the second cylinder bore 26 to a diametrical center of the third cylinder bore 28. The engine block 20 may define a third distance (D3) from a diametrical center of the third cylinder bore 28 to a diametrical center of the fourth cylinder bore 30. The first and third distances (D1, D3) may be different from the second distance (D2). In the present non-limiting example, the first and third distances (D1, D3) may be greater than the second distance (D2).
Therefore, the bore spacing along the engine block 20 may provide an overall reduced length of the engine block 20 relative to an arrangement having an equal spacing between cylinder bores based on the largest cylinder bore size. The reduced length of the engine block 20 may alternatively be characterized based on the radial distances between adjacent cylinder bores.
In the example shown in
The first radial distance (Rd1) may be less than two hundred and five percent of the first diameter (φ1) (i.e., the greater of the first and second diameters (φ1, φ2)). Similarly, the second radial distance (Rd2) may be less than two hundred and five percent of the fourth diameter (φ4) (i.e., the greater of the third and fourth diameters (φ3, φ4)). In the present non-limiting example, the first radial distance (Rd1) is less than twice the first diameter (φ1) and the second radial distance (Rd2) is less than twice the fourth diameter (φ4).
It is understood that the present disclosure may be applied to arrangements where the location of the working cylinders and EGR cylinders are reversed (i.e., first and fourth cylinder bores 24, 30 located between the second and third cylinder bores 26, 28). Further, while described in combination with a four cylinder inline engine configuration, it is understood that the present teachings apply to any number of piston-cylinder arrangements and a variety of reciprocating engine configurations including, but not limited to, V-engines, inline engines, and horizontally opposed engines, as well as both overhead cam and cam-in-block configurations.
In the example shown in
The first radial distance (Rd11) may be less than two hundred and five percent of the first diameter (φ11) (i.e., the greater of the first and second diameters (φ11, φ22)). Similarly, the second radial distance (Rd22) may be less than two hundred and five percent of the third diameter (φ33) (i.e., the greater of the second and third diameters (φ22, φ33)). In the present non-limiting example, the first radial distance (Rd11) is less than twice the first diameter (φ11) and the second radial distance (Rd22) is less than twice the third diameter (φ33). A third radial distance (Rd33) is defined from point (P11) to point (P44) and may be less than three hundred and ten percent of the first diameter (φ11).
In the example shown in
The first radial distance (Rd111) may be less than two hundred and five percent of the first diameter (φ111) (i.e., the greater of the first and second diameters (φ111, φ222)). Similarly, the second radial distance (Rd222) may be less than two hundred and five percent of the third diameter (φ3) (i.e., the greater of the third and fourth diameters (φ333, φ444)). In the present non-limiting example, the first radial distance (Rd111) is less than twice the first diameter (φ111) and the second radial distance (Rd222) is less than twice the third diameter (φ444).
