INTERGRATED TUNED INDUCTION SYSTEM

Abstract: A plenum (106) is surrounded by runners (108, 110, 112, 114) that spiral around the plenum sidewall to the entrances to the engine cylinders. The circumferential extent of each runner exceeds 360 degrees about a longitudinal axis (122) of the plenum. Portions of the runners share common wall portions with portions of the plenum.

Description: BACKGROUND AND SUMMARY OF THE INVENTION This invention relates generally to the air induction systems of internal combustion engines and more specifically it relates to an integrated tuned air induction system. It is a known fact that performance of an internal combustion engine can be improved by tuning the air induction system. Such tuning involves the use of runners, or tubes, of particular lengths. In an automobile however, the packaging of tuned tubes, or runners, is a challenge to engineers and designers. The state of the art is represented by patents including US-A-4,254,746; 4,446,823; 4,497,287; 4,516,538; 4,523,560; 4,643,138; 4,664,075; 4,669,428; 4,719,879; 4,760,703; 4,776,313; and 4,829,944. They show various types of induction air circuits. US-A-4 446 823 shows an induction air circuit according to the preamble of claim 1. Its runners and plenum are formed by separate castings assembled together. The present invention relates to a tuned air induction system in which various component parts are packaged into an integrated system. The present invention is well suited to enable a tuned air induction system to be implemented in an automobile with the objective of simplifying manufacturing and assembly procedures. The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, having portions exploded and broken away, illustrating an integrated tuned air induction system according to the present invention. FIG. 2 is a transverse cross-sectional view on an enlarged scale illustrating the components in assembly and taken generally in the direction of arrows 2-2 in FIG. 1. FIG. 3 is a fragmentary cross-sectional view on an enlarged scale taken in the direction of arrows 3-3 in FIG. 1. FIG. 4 is a top plan view of a further embodiment of a portion of an engine air induction system. FIG. 5 is a right end view of Fig. 4. FIG. 6 is a fragmentary view looking in the direction of arrows 6-6 in Fig. 5. FIG. 7 is a fragmentary view, on an enlarged scale, looking in the direction of arrow 7 in Fig. 5. FIG. 8 is a cross-sectional view taken in the direction of arrows 8-8 in Fig. 7. FIG. 9 is a cross-sectional view taken in the direction of arrows 9-9 in Fig. 4. FIG. 10 is a cross-sectional view taken in the direction of arrows 10-10 in Fig. 4. FIG. 11 is a cross-sectional view taken in the direction of arrows 11-11 in Fig. 4. FIG. 12 is a cross-sectional view taken in the direction of arrows 12-12 in Fig. 4. FIG. 13 is a cross-sectional view taken in the direction of arrows 13-13 in Fig. 5. FIG. 14 is a cross-sectional view taken in the direction of arrows 14-14 in Fig. 5. DESCRIPTION OF THE PREFERRED EMBODIMENT The drawings show by way of example a four cylinder internal combustion engine 10 with which is associated an integrated tuned air induction system 12. The engine has a cylinder head 14 containing an intake port 16 via which a combustible air-fuel mixture enters each engine cylinder. Air passes through system 12 and through air passages in a fuel rail block 18 that is fastened to cylinder head 14. The fuel rail block contains four electromagnetic fuel injectors 20, each of which is poised to spray fuel in suitably timed relation to the engine operation into each intake port 16 for mixture with air that has passed through system 12. System 12 comprises an air intake 22 through which air enters an air filter compartment in the direction indicated by the arrow 24. The air filter compartment comprises a cover 26 that fits over an annular air filter element 28 to capture the air filter element between an annular end wall 30 of cover 26 and an imperforate end wall 32 of a main body part 34. The airflow passes radially outwardly through the air filter element 28 and enters the entrance end 36 of a tube 38 that forms a passage running parallel to engine 12 and passing the four cylinders that are served by the integrated tuned air induction system 12. Wall 32 is shown broken away in FIG. 1, and it is to be understood that this wall covers the end of body 34 except for the entrance end 36 of tube 38. Alternately, the air filter element could be a panel type element fitting diagonally within the compartment with the upper edge sealing against wall 32, the lower edge sealing against wall 30, and the side edges sealing against the sides of the cover. The exit end of tube 38 cannot be directly seen in FIG. 1, but it is at the far end of main body 34. Tube 38 has a substantially constant cross-sectional area throughout its length and forms part of the tuning system. An extension piece 40 has an entrance end 42 that is fitted to the exit end of tube 38. Extension piece 40 provides a means to create approximately a 180° turn in the airflow after the flow has passed through tube 38. The outlet or exit end 44 of extension piece 40 has a circular shape and faces in a direction that is parallel to the direction in which the entrance end 42 faces. Extension piece 40 serves to maintain the cross-sectional area of tube 38 substantially constant so that the extension piece 40 also forms a part of the tuning system even though the shape of the cross-section changes. A circular cylindrical air body 46 has an entrance end 48 that fits to the exit end 44 of extension piece 40, and it also has an outlet or exit end 50 that fits to the entrance end of a plenum zone 52. That entrance end of plenum zone 52 is at the far end of main body 34. The plenum zone 52 lies parallel to tube 38 and passes the four engine cylinders that are served by induction air system 12. Wall 32 closes the near end of the plenum zone. The air body 46 contains a butterfly 54 that is positioned by means of a lever 56 to control the airflow through air induction system 12. The exit end 44 of piece 40 has a circular shape that provides a slip fit with the entrance end of air body 46, and the entrance of plenum zone 52 also has a shape that provides a slip fit with the exit end of air body 46. The slip fit joint between air body 46 and extension piece 40 is shown in Fig. 3 and comprises a circular seal 55 that seals a radially facing surface of the air body with an opposite facing surface of the extension piece. Main body 34 comprises four pairs of spiral runners that serve to communicate plenum zone 52 with corresponding cylinders of engine 10. Each pair of runners comprises a longer and narrower runner 58 and a shorter and wider runner 60. The shorter and wider runner is arranged in a nested fashion within the longer and narrower one so that they share a common wall. Each runner 58, 60 has a corresponding entrance 62, 64 that is in communication with plenum zone 52. The exit end 66, 68 of each runner 58, 60 in main body 34 is disposed at a corresponding entrance, 70, 72 respectively, in fuel rail block 18, and the fuel rail block has passages, 74 and 76 respectively, that constitute the terminations of the runners. The runners 58 and 60 are also part of the tuning system. A wave deflector 78 is disposed in fuel rail block 18 at the termination of each runner 60. The wave deflectors are operated by an actuator (not shown) for opening and closing runners 60. In this way selective tuning of the air induction system may be accomplished. A further feature of the main body 34 is that it includes a wall 80 that aids in the mounting and support of the main body from the engine. This wall 80 in general extends downwardly from the outer face of fuel rail block 18, forms the outer wall of tube 38 and extends outwardly around the bottom of the main body to provide a cradle-like support for the runners. Wall 80 has apertures for the exit ends of the runners 58, 60. The main body 34, which comprises tube 36, plenum zone 52, runners 58, 60, and wall 80, may be fabricated as a one-piece plastic part by a suitable manufacturing technique, and by way of example, lost core molding may be one such suitable technique. It will also be observed that the runners comprise outer walls 82 and side walls 84. Between the side walls 84 of adjacent pairs of runners the plenum zone 52 comprises an outer wall 86. Figs. 4-14 present a portion of another embodiment that is designated by the general reference 100. Specifically, these Figs. disclose a single part 102 in which a plenum entrance section 104, a plenum 106, four spiral runners 108, 110, 112, 114, and a fuel rail 116 are integrated. Like the corresponding part of the first embodiment of Fig. 1, part 102 is fabricated from suitable plastic material by a suitable technique such as lost core molding. Not shown in Figs. 4-14 are those portion of the system that are upstream of entrance section 104, namely the air body and air filter compartment, nor is the engine to which fuel rail 116 attaches shown. Also not shown are the fuel injectors and the fuel pressure regulator which are assembled to the fuel rail in the functioning system. Entrance section 104 has a generally circular cross-sectional shape and begins at a flange 118 that provides for attachment to the non-illustrated upstream components. From flange 118 the entrance section continues along a curved path and opens into one lengthwise end of plenum 106. Plenum 106 may be considered to have a generally cylindrical walled shape extending from entrance section 104 to the other lengthwise plenum end which is fully closed. As viewed in transverse cross section through the plenum, the plenum sidewall is generally uniform in shape and size throughout its full length, except for the approximately one-quarter of its length that lies immediately contiguous entrance section 104. That particular portion contains a slight indentation 120 (Fig. 4) that has been designed into this particular embodiment for the purpose of providing clearance to closely adjacent engine compartment structure (not shown) which would otherwise interfere with part 100 in the absence of indentation 120. The four runners extend spirally about the plenum to establish communication between plenum and the entrance to a corresponding engine cylinder when the part 102 is functionally installed on an engine. For convenience of description, let it be assumed that the reference numeral 122 (Fig. 10) denotes a particular longitudinal plenum axis that is located generally centrally of the plenum. As viewed transversely of axis 122, each runner has a beginning 124 that is in communication with the plenum at about the 11 o'clock position as viewed in the direction of Fig. 10. Each runner is arranged generally transversely of the plenum, with the length of each runner extending in a spiral manner around the plenum. Each runner 108, 110, 112, 114 spirals in excess of 360 degrees about axis 122 to terminate in an ending 126 that is placed in communication with the entrance of a corresponding engine cylinder when part 102 is assembled to an engine. In the particular configuration that is illustrated by Figs. 1-14, the spacing distance between the runner endings 126, which is established by the particular engine design, exceeds the spacing distance between the runner beginnings 124, which in this instance may be considered nil since the runner beginnings are immediately contiguous with immediately adjacent runners sharing common wall portions. Therefore, while each runner has essentially zero lead at it spirals from its 11 o'clock beginning to approximately 9 or 10 o'clock, each runner has a different lead from the 9 or 10 o'clock position to its ending 126. This lead progressively increases in succession from runner to runner, being quite small for runner 108, but largest for runner 114. Hence, a segment of runner 108 immediately contiguous its ending 126 almost fully overlaps a segment that is immediately contiguous its beginning 124; a segment of each remaining runner immediately contiguous its ending partially overlaps a segment that is immediately contiguous its beginning; and the percentage of overlap of each runner becomes progressively less in succession from runner 108 to runner 114. As can be seen in Fig. 10, a portion of runner 108 and a portion of plenum 106 share a common wall; the same holds true for each of the other runners. The construction does however have a void 128 where there is no wall sharing. Fuel rail 116 integrally merges with the end segments of the runners and comprises four injector sockets 130, each associated with a corresponding runner. Each socket is adapted to receive a corresponding electromagnetic fuel injector (not shown). The fuel rail further comprises a fuel pressure regulator socket 132 adapted to receive a fuel pressure regulator (not shown). Running along the length of the fuel rail from separate ports at the left-hand end as viewed in Fig. 4 are a fuel supply passage 134 and a fuel return passage 136. The fuel supply passage is in communication with sockets 130 and serves to convey liquid fuel to the injectors when the injectors are functionally installed in the sockets. The supply passage is communicated with the inlet to a fuel pressure regulator when the regulator is functionally associated with its socket 132. Excess fuel is returned from the pressure regulator to the fuel tank (not shown) via return passage 136.

Claims: An induction air circuit for a multi-cylinder internal combustion engine comprising a plenum zone (52; 106) that is supplied with air from an air intake (22; 104), and for each cylinder, a corresponding spiral runner means (58, 60; 108, 110, 112, 114) which leads from said plenum zone and through which air is supplied from said plenum zone to the corresponding cylinder, said runner means laterally bounding said plenum zone at respective locations along the axial length of said plenum zone, at least one of said runner means having an air entrance (62, 64; 124) at said plenum zone and spiraling from said air entrance in excess of 360 degrees about a longitudinal axis of said plenum zone to an air exit (66, 68; 126) through which air passes to the corresponding cylinder, a first segment of said at least one runner means and a second segment of said at least one runner means which is disposed at least 360 degrees about said axis from said first segment sharing a common wall portion, characterized in that said plenum zone and runner means are embodied in a single plastic part. An induction air circuit for a multi-cylinder internal combustion engine as set forth in claim 1 characterized further in that said at least one runner means comprises two runners (58, 60) arranged as a nested set in which they share another common wall portion extending along substantially their entire lengths. An induction air circuit for a multi-cylinder internal combustion engine as set forth in claim 1 characterized further in that said at least one runner means (108, 110, 112, 114) shares a further common wall with an immediately adjacent one of said runner means. An induction air circuit for a multi-cylinder internal combustion engine as set forth in claim 3 characterized further in that the sharing of said further common wall by said at least one runner means and said immediately adjacent one of said runner means takes place along respective segments beginning at said plenum zone, but stopping short of the cylinders. An induction air circuit for a multi-cylinder internal combustion engine as set forth in claim 1 characterized further in that the air entrance of said at least one runner means is disposed approximately at the 11 o'clock position as viewed axially of said plenum zone. An induction air circuit for a multi-cylinder internal combustion engine as set forth in claim 5 characterized further in that a fuel rail (116) is embodied in said single plastic part and merges with said each of said runner means at the corresponding air exit thereof.

Inventors: SHILLINGTON, RONALD GEORG
Applicants: SIEMENS AKTIENGESELLSCHAFT
Application year: 1990
Main classification: F02M35
IPC codes: F02M55, F02M35, F02B27