Patent Application
20130319381
The present disclosure relates to engine air intake systems.
This section provides background information related to the present disclosure which is not necessarily prior art.
Internal combustion engines may include exhaust gas recirculation systems to provide exhaust gas to the combustion chambers for a subsequent combustion event. In order to provide exhaust gas flow to the combustion chambers a pressure differential is needed between the exhaust flow path of the engine and the location in the intake system where the exhaust gas is reintroduced.
An engine assembly may include an engine block defining a first cylinder bore, a cylinder head coupled to the engine block and defining a first intake port and a first exhaust port in communication with the first cylinder bore, a first intake valve located in the first intake port, a first exhaust valve located in the first exhaust port, a first intake runner and a first exhaust gas recirculation passage. The first intake runner may define an intake air supply passage in communication with the first intake port and may include a first restricted flow region forming a venturi. The first exhaust gas recirculation passage may be in communication with the first restricted flow region and may provide exhaust gas from the engine assembly to the first intake runner at the first restricted flow region.
In one arrangement, the first intake runner may be defined in the cylinder head. In an alternate arrangement, an intake manifold coupled to the cylinder head may define the first intake runner.
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. As used herein, the term “module” refers to an application specific integrated circuit (ASIC), an electronic circuit, and/or a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs.
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.
With reference to
The engine block 12 may define cylinder bores 28. While illustrated as an inline four cylinder arrangement, it is understood that the present disclosure is not limited to such arrangements and applies equally 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. The cylinder head 14 may be coupled to the engine block 12 and may define intake and exhaust ports 30, 32, intake and exhaust runners 34, 36 and EGR ports 38. The intakes valves 16 may be located in the intake ports 30 and the exhaust valves 18 may be located in the exhaust ports 32. The intake and exhaust manifolds 20, 22 may each be coupled to the cylinder head 14 with the intake manifold 20 in communication with the intake ports 30 and the exhaust manifold 22 in communication with the exhaust ports 32. In arrangements including a throttle valve 26, the throttle valve 26 may control air flow (A) to the intake manifold 20.
The intake runners 34 may each define a restricted flow region 40 forming a venturi. The intake runners 34 may be formed with the cylinder head 14 during casting of the cylinder head 14 and the restricted flow region 40 forming the venturi may be integrally formed with the cylinder head 14 during casting. In arrangements including two intake ports 30 per cylinder bore 28 (seen in
The restricted flow region 40 forming the venturi may be located in the inlet region 42. The EGR port 38 may additionally be located in the inlet region 42, and more specifically in the restricted flow region 40 forming the venturi. The EGR port 38 may extend through a circumferential wall 50 defining the venturi to provide communication between the intake runner 34 and exhaust gas from the engine.
The EGR assembly 24 may include EGR passages 52 extending from the exhaust gas flow path (E) exiting the exhaust manifold 22 to each of the EGR ports 38 and an EGR valve 54 in communication with the exhaust gas flow path (E) and the EGR passages 52 and controlling communication between the exhaust gas from the exhaust gas flow path (E) and the EGR passages 52. In the present non-limiting example including a four cylinder arrangement, a first EGR passage 52 may extend to a first intake runner 34 in communication with first and second intake ports 30 for the first cylinder bore 28, a second EGR passage 52 may extend to a second intake runner 34 in communication with first and second intake ports 30 for the second cylinder bore 28, a third EGR passage 52 may extend to a third intake runner 34 in communication with first and second intake ports 30 for the third cylinder bore 28, and a fourth EGR passage 52 may extend to a fourth intake runner 34 in communication with first and second intake ports 30 for the fourth cylinder bore 28.
In an alternate arrangement, seen in
Similar to the arrangement shown in
The throttle valve 26, 126 may generally control a pressure drop within the intake manifold 20, 120. During wide open throttle arrangements, and in engines without a throttle valve, the intake manifold 20, 120 may experience little or no pressure drop relative to atmospheric pressure. However, the venturi defined by the restricted flow regions 40, 140 may still provide for exhaust gas flow to the intake ports 30, 130 via the EGR assembly 24, 124. In the arrangements discussed above, the EGR valve 54, 154 could be located before or after a three-way catalyst in the exhaust flow path (E), used in combination with an EGR cooler (not shown) and/or used in combination with a turbocharger (not shown).
