The present disclosure relates to engine camshaft arrangements.
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 and air flow to the combustion chambers and exhaust ports to direct exhaust gases from the combustion chambers. Camshafts are used to displace intake and exhaust valves between open and closed positions to selectively open and close the intake and exhaust ports.
An engine assembly may include an engine block, a first cylinder head, a second cylinder head, first, second and third valves, first, second and third valve lift mechanisms, a first camshaft and a second camshaft. The engine block may include a first bank defining a first cylinder bore and a second bank defining a second cylinder bore disposed at an angle relative to the first cylinder bore. The first cylinder head may be coupled to the first bank of the engine block and may define a first port in communication with the first cylinder bore and a second port in communication with the first cylinder bore. The second cylinder head may be coupled to the second bank of the engine block and may define a third port in communication with the second cylinder bore. The first valve may be located in the first port, the second valve may be located in the second port, and the third valve may be located in the third port. The first valve lift mechanism may be engaged with the first valve, the second valve lift mechanism may be engaged with the second valve, and the third valve lift mechanism may be engaged with the third valve. The first camshaft may be engaged with the first valve lift mechanism and the third valve lift mechanism. The second camshaft may be engaged with the second valve lift mechanism.
In another arrangement, an engine assembly may include an engine block, a first cylinder head, a second cylinder head, a first camshaft, a second camshaft, and a third camshaft. The engine block may include a first bank defining a first cylinder bore and a second bank disposed at an angle relative to the first bank and defining a second cylinder bore. The first cylinder head may be coupled to the first bank of the engine block and the second cylinder head may be coupled to the second bank of the engine block. The first camshaft may be rotationally supported by the engine block between the first and second cylinder bores. The second camshaft may be rotationally supported on the first cylinder head and the third camshaft may be rotationally supported on the second cylinder head.
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 engine assembly 10 will be described with respect to one of first cylinder bores 28 and one of second cylinder bores 32 for simplicity with understanding that the description applies equally to the remainder of the first and second cylinder bores 28, 32. As seen in
The valvetrain assembly 18 may include first, second and third camshafts 50, 52, 54, first, second, third and fourth valves 56, 58, 60, 62, and first, second, third and fourth valve lift mechanisms 64, 66, 68, 70. The first valve 56 may be located in the first port 34 and may define a first intake valve for the first cylinder bore 28 and the second valve 58 may be located in the second port 36 and may define a first exhaust valve for the first cylinder bore 28. The third valve 60 may be located in the third port 38 and may define a first intake valve for the second cylinder bore 32 and the fourth valve 62 may be located in the fourth port 40 and may define a first exhaust valve for the second cylinder bore 32.
The first valve lift mechanism 64 may be engaged with the first valve 56, the second valve lift mechanism 66 may be engaged with the second valve 58, the third valve lift mechanism 68 may be engaged with the third valve 60 and the fourth valve lift mechanism 70 may be engaged with the fourth valve 62. The first camshaft 50 may be engaged with the first valve lift mechanism 64 and the third valve lift mechanism 68. The second camshaft 52 may be engaged with the second valve lift mechanism 66 and the third camshaft 54 may be engaged with the fourth valve lift mechanism 70.
In the exemplary four valve arrangement illustrated in
An additional valve lift mechanism 80 (similar to the first valve lift mechanism 64) may be engaged with the second intake valve 72 and the first camshaft 50 and an additional valve lift mechanism 82 (similar to the second valve lift mechanism 66) may be engaged with the second exhaust valve 74 and the second camshaft 52. Similarly, an additional valve lift mechanism 84 (similar to the third valve lift mechanism 68) may be engaged with the second intake valve 76 and the first camshaft 50 and an additional valve lift mechanism 86 (similar to the fourth valve lift mechanism 70) may be engaged with the second exhaust valve 78 and the third camshaft 54.
In the present non-limiting example, the first camshaft 50 is rotationally supported by the engine block 20 between the first and second cylinder bores 28, 32. More specifically, the first and second banks 26, 30 may form a V-configuration as indicated above with the first camshaft 50 located within a central region of the V-configuration. The first port 34 and the third port 38 may each be located on an inboard side of the first and second cylinder heads 22, 24 and may extend toward the central region of the V-configuration formed by the engine block 20. The second intakes ports 42, 46 may additionally be located on the inboard side of the first and second cylinder heads 22, 24 and may extend toward the central region of the V-configuration formed by the engine block 20.
The second camshaft 52 may be rotationally supported on the first cylinder head 22 and the third camshaft 54 may be rotationally supported on the second cylinder head 24. As seen in
As seen in
The first camshaft 50 may be located below the second and third camshafts 52, 54. More specifically, the first camshaft 50 may be located below the first and second cylinder heads 22, 24 and below the first and third valves 56, 60. The second camshaft 52 may be located above the first cylinder head 22 and the second valve 58. The third camshaft 54 may be located above the second cylinder head 24 and the fourth valve 62.
As seen in
The housing member 104 may form a lock pin housing defining an opening 124 containing the locking mechanism 110 therein. While described in combination with a deactivating lift mechanism, it is understood that the present disclosure applies equally to a variety of other switchable valve lift mechanisms as well as fixed lift mechanisms (i.e., non-switchable valve lift mechanisms). The locking mechanism 110 may include first and second locking pins and a biasing member (not shown). The biasing member may force the locking pins radially outward from one another.
The first and second locking pins may be displaceable between locked and unlocked positions by selectively providing pressurized oil to the second oil passage 122. In the locked position, the first and second locking pins fix the pushrod 96 for displacement with the lifter body 102. In the unlocked position, the first and second locking pins allow relative displacement between the pushrod 96 and the lifter body 102.
The lost motion mechanism 112 may include a retaining member 126 and a biasing member 128. The retaining member 126 may be axially fixed to the housing member 104 and the biasing member 128 may engage the retaining member 126 and the lifter body 102, biasing the cam follower 114 into engagement with the a cam lobe 130 of the first camshaft 50. The cam lobe 130 may displace the lifter body 102 toward the retaining member 126 against the force of the biasing member 128 as a peak 132 of the cam lobe 130 engages the cam follower 114. The lifter body 102 may be returned to an initial position by the biasing member 128 as a base region 134 of the cam lobe 130 engages the cam follower 114.
When the first and second locking pins are in the locked position, the cam lobe 130 of the first camshaft 50 may displace the housing member 104, and therefore the pushrod 96, with the housing member 104 to open the first valve 56 based on an engagement between the peak 132 of the cam lobe 130 and the cam follower 114. When the first and second locking pins are in the unlocked position, the lifter body 102 may be displaced relative to the housing member 104 when the cam follower 114 is engaged with the peak 132 of the cam lobe 130, preventing opening of the first valve 56.
In a first non-limiting example, seen in
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Number | Date | Country | |
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20120186544 A1 | Jul 2012 | US |