Abstract:
All the components constituting an air-intake module for an internal combustion engine, including an air cleaner for cleaning air and manifold pipes for distributing air into each cylinder of the engine, are integrated in a single unit. A mounting flange connected to engine side ends of the manifold pipes is fixed to the engine for mounting the air-intake module as a whole. The air cleaner and other components of the module are located under the mounting flange and the manifold pipes, so that the mounting of the module is not obstructed by components constituting the module. An air cleaner element for filtering the intake air is slidably inserted into the air cleaner at a position where the element can be easily serviced from the outside of the module without dismounting any components of the module.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims benefit of priority of Japanese Patent Application No. Hei-9-298721 filed on Oct. 30, 1997, the content of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air-intake module for an internal combustion engine, in which an air cleaner, a throttle body, a surge tank, intake manifold pipes and other components are integrated into a single module that can be mounted on the engine as a single unit. 
     2. Description of Related Art 
     An air-intake device for an internal combustion engine includes an air cleaner, a throttle body, a surge tank, an intake manifold and other components. A throttle valve installed in the throttle body is operated by an acceleration pedal, so that an amount of intake air is controlled. The intake air is mixed with fuel and supplied to the engine. An air-intake module into which all components are integrated is disclosed, for example, in JP-A-6-81735 and EP-0523027-A2. It is possible to reduce the number of parts and to simplify an assembling process by integrating components in a single module. 
     In the conventional integrated modules, one end of a manifold is mounted on and fixed to the engine, and an air cleaner is disposed above the manifold. Therefore, a working space for mounting the module on the engine is covered by the air cleaner, and, accordingly, it is hard to mount the module on the engine. For example, in the air-intake module disclosed in JP-A-6-81735, an upper portion of a manifold is covered by an air cleaner case. The air cleaner case has to be disassembled from the module when the module is mounted on an engine. Otherwise, there is no working space for mounting. In the air-intake module disclosed in EP-0523027-A2, a whole rear portion of a mounting flange disposed at one end of a manifold is covered by an filter housing. Therefore, an air cleaner element disposed in the housing and its upper cover have to be removed from the module to mount the module on an engine. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above-mentioned problem, and an object of the present invention is to provide an air-intake module for an internal combustion engine, which can be easily mounted on an engine without removing components or parts from the module. Another object of the present invention is to provide an air-intake module in which an air cleaner element can be easily installed in and removed from the module for maintenance service. 
     An air cleaner containing an air cleaner element therein and manifold pipes for supplying air to the engine are connected through connecting members, thereby forming a single module. The connecting members include a connecting duct, a surge tank and a throttle body. One end of each manifold pipe is connected to the surge tank, and the other end of each manifold pipe is connected to a mounting flange. The mounting flange and the manifold pipes are positioned above the air cleaner so that the manifold pipes embrace the air cleaner thereunder. The mounting flange is fixed to the engine by bolts and screws, thereby mounting the module on the engine as a whole. A working space for tightening screws are provided in the module, and the working line extends perpendicularly to the surface of the mounting flange above the air cleaner so that the air cleaner or other components of the module do not interfere with the working line. Therefore, the module can be easily mounted on the engine without disassembling any components from the module. Preferably, the throttle body is connected to a substantial center of the surge tank, and the manifold pipes are formed in an equal length, so that air distribution to each engine cylinder becomes uniform. 
     The air cleaner element may be slidably and vertically inserted into the air cleaner at a position where the air cleaner is not covered by the manifold pipes. Alternatively, the air cleaner element may be slidably and horizontally inserted into the air cleaner at an upper portion of the air cleaner. In both cases, the air cleaner element can be easily serviced without being obstructed by other components of the module. It is also possible to form the air cleaner element in a cylindrical shape which extends horizontally to the inner space of the air cleaner or extends outward form the air cleaner. Preferably, the cylindrical surface of the air cleaner element is serpentined so that it expands or contracts in its axial direction. 
     Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiments described below with reference to the following drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing an air-intake module as a first embodiment of the present invention; 
     FIG. 2 is a front view showing the air-intake module shown in FIG. 1; 
     FIG. 3 is a top view showing the air-intake module shown in FIG. 1; 
     FIG. 4 is a right side view showing the air-intake module shown in FIG. 1; 
     FIG. 5 is a cross-sectional view showing the air-intake module shown in FIG. 1, taken along a line V--V of FIG. 3; 
     FIG. 6 is a cross-sectional view showing the air-intake module shown in FIG. 1, taken along a line VI--VI of FIG. 3; 
     FIG. 7 is a front view showing an air-intake module as a second embodiment of the present invention; 
     FIG. 8 is a top view showing the air-intake module shown in FIG. 7; 
     FIG. 9 is a right side view showing the air-intake module shown in FIG. 7; 
     FIG. 10 is a cross-sectional view showing the air-intake module shown in FIG. 7, taken along a line X--X of FIG. 8; 
     FIG. 11 is a cross-sectional view showing the air-intake module shown in FIG. 7, taken along a line XI--XI of FIG. 8; 
     FIG. 12 is a cross-sectional view showing a modified form of the first and second embodiments, and shows a similar cross-section as in FIG. 5; and 
     FIG. 13 is a cross-sectional view showing another modified form of the first and second embodiments, and shows a similar cross-section as in FIG. 5. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first embodiment of the present invention will be described, referring to FIGS. 1-6. The most important feature of the present invention resides in that an air cleaner is placed under a mounting flange of an air-intake module to secure a working space for mounting the module on an engine. 
     FIG. 1 shows the air-intake module as the first embodiment of the present invention, FIG. 2 a front view, FIG. 3 a top view, FIG. 4 a right side view, and FIGS. 5, 6 cross-sectional views, all showing the first embodiment. Following description will be made referring to all of those drawings. The air-intake module includes an air cleaner 10 which cleans air taken into the module from an air-intake port 12, an intake manifold 20 having four manifold pipes 24 and a mounting flange 22 fixed to one end of the manifold pipes 24, a surge tank 30 connected to the other end of the manifold pipes 24, a throttle body 40 connected to a substantial center of the surge tank 30, and a duct 50 which connects the throttle body 40 and the air cleaner 10. All of those components are integrated into a single module which is mounted on an engine as a whole. 
     The air cleaner 10 (as best seen in FIG. 5) is composed of an air cleaner case 18, an air cleaner element 14 disposed in the air cleaner case 18, and a cap 16 disposed on an upper end portion of the air cleaner case 18. The air cleaner element 14 divides an inside space of the air cleaner case 18 into two spaces, a dusty-side space 80 and a clean-side space 82. The air cleaner element 14 is made of non-woven cloth, filtering paper or the like. A cross-sectional area of the air cleaner case 18 is substantially rectangular and is divided into two spaces by the air cleaner element 14 disposed substantially vertically at a position near one end of the air cleaner case 18. Air introduced into the dusty-side space 80 through the air-intake port 12 is filtered and cleaned by the air cleaner element 14, and then introduced into the clean-side space 82. The air cleaner element 14 can be installed or removed for maintenance services by slidably moving it in a direction perpendicular to the air flow direction. When the air cleaner element 14 is installed in the air cleaner case 18, it is air-tightly held in position by a seal member (not shown) formed around its periphery. The cap 16 closes an opening for installing and removing the air cleaner element 14 and also serves as a grip for taking out and inserting the air cleaner element 14. 
     A space 84 is formed at a part of a bottom portion of the air cleaner case 18. The space 84 is connected to the connecting duct 50. The air in the clean-side space 82 is introduced into the space 84 and then enters into the connecting duct 50. The connecting duct 50 connects the space 84 and the throttle body 40, and introduces the cleaned air into the throttle body 40. A throttle valve (not shown) which is operated to control an amount of air to be introduced into the engine by an acceleration pedal is disposed in the throttle body 40. The surge tank 30 is box-shaped (as best seen in FIG. 1), and air is introduced therein from the throttle body 40. Pressure pulsation of the air introduced into the surge tank 40 is alleviated therein. The manifold 20 having the manifold pipes 24 (the number of the manifold pipes corresponds to the number of cylinders of the engine) is connected to the surge tank 30 at a top surface thereof. Air in the surge tank 30 is sucked into the manifold pipes 24 and then into the engine cylinders through manifold holes 26 formed at each end of the manifold pipes 24. Because the throttle body 40 is connected to the center portion of the surge tank 30, harmful noises caused by sucking air are suppressed, and air is distributed equally to each manifold pipes 24. 
     The mounting flange 22 for mounting the integrated module on the engine is formed at the engine side end of the intake-manifold 20. Each manifold pipe 24 is connected to the mounting flange 22. Plural mounting holes 28 are formed on the mounting flange 22. Bolts (not shown) are inserted into the mounting holes 28, and a whole module is fixed to the engine by screwing nuts (not shown) onto the bolts. Each manifold pipe 24 extends from the surge tank 30 toward the engine so that it covers the upper side of the air cleaner 10. The manifold ports 26 of the manifold pipes 24 are located above the air cleaner 10. The bolts for mounting the module on the engine extend perpendicularly to the surface of the mounting flange 22 through the mounting holes 28. In other words, the longitudinal direction of the mounting bolts (a working line for mounting the module on the engine) is perpendicular to the surface of the mounting flange 22 and extends above the air cleaner 10, so that the air cleaner 10 does not interfere with a working space for mounting the module on the engine. 
     Now, the function of the first embodiment will be described. Air introduced into the dusty-side space 80 through the air-intake port 12 is cleaned by the filter element 14 and then enters into the clean-side space 82. The cleaned air flows into the surge tank 30 through the space 84, the connecting duct 50 and the throttle body 40. The air in the surge tank 30 is distributed to four manifold pipes 24 and is sucked into the engine cylinders through the manifold ports 26. The amount of air supplied to the engine cylinders is controlled by the throttle valve installed in the throttle body 40. A fuel injector (not shown) is installed for each engine cylinder, and fuel injected from the fuel injector is mixed with air supplied from the air-intake module. 
     As described above, since the working line for mounting the module on the engine extends above the air cleaner 10 so that the air cleaner 10 does not interfere with working line, the air-intake module can be easily mounted on the engine as a whole without disassembling any components from the module. In addition, the manifold pipes 24 can be arranged freely because no other parts interfere with the space for the manifold pipes 24. Accordingly, it is possible to design the length of each manifold pipe 24 to be equal. It is also possible to connect the throttle body 40 to the surge tank 30 at a substantial center of the surge tank 30. Because of the structure of the first embodiment above described, harmful noises of air-intake are alleviated, and intake-air is equally distributed to each engine cylinder. 
     The air cleaner element 14 is placed in a side portion of the air cleaner case 18 which is not covered by the manifold pipes 24, though most part of the air cleaner case 18 is covered by the manifold pipes 24 (as better seen in FIGS. 1 and 5). The air cleaner element 14 can be inserted into and removed from the air cleaner case 18 in the vertical direction without being obstructed by other components. Therefore, the maintenance service for the air cleaner element 14 is easily performed. 
     A second embodiment of the present invention will be described, referring to FIGS. 7-11. FIG. 7 is a front view of the air-intake module as the second embodiment, FIG. 8 a top view, FIG. 9 a right side view, FIG. 10 a cross-sectional view (taken along a line X--X of FIG. 8), and FIG. 11 a cross-sectional view (taken along a line XI--XI of FIG. 8). In the second embodiment, the air cleaner element 114 is placed at an upper portion of the air cleaner case 118. Other structures of the second embodiment are similar to those of the first embodiment. The air-intake module includes an air cleaner 110 which cleans air sucked from an air-intake port 112 formed at an end of a duct 100, a manifold 20 having manifold pipes 24 and a mounting flange 22 formed at an engine side end of the manifold 20, a surge tank 30 connected to the other end of the manifold 20, a throttle body 40 connected to a center portion of the surge tank 30, and a connecting duct 50 which connects the throttle body 40 and the air cleaner 110. 
     As better seen in FIG. 10, the air cleaner 110 is composed of an air cleaner case 118, an air cleaner element 114 disposed in an upper portion of the air cleaner case 118, and a cap 116 disposed at a right side end of the air cleaner case 118. A space in the air cleaner case 118 is divided into two spaces by an air cleaner element 114, a dusty-side space 180 into which outside air is introduced and a clean-side space 182 into which air cleaned by the air filter element 114 is introduced. The air cleaner element 114 is inserted into and removed from the air cleaner case 118 by slidably moving it in a horizontal direction. When the air cleaner element 114 is installed in the air cleaner case 118, it is air-tightly held in the air cleaner case 118 by a seal formed around a periphery of the air cleaner element 114. Since other structures are similar to those of the first embodiment, detailed description thereof is not repeated here. 
     The mounting flange 22 is located above the air cleaner 110 and other components, and the working line for mounting the air-intake module on the engine extends above the air cleaner 110. Accordingly, the air-intake module can be easily mounted on the engine in the same manner as in the first embodiment. The air cleaner element 114 is placed at the upper portion of the air cleaner case 118 and is slidably removable in the horizontal direction. Therefore, the maintenance service of the air cleaner element 114 can be easily performed without being obstructed by other components though the manifold pipes 24 cover a whole space above the cleaner 110. 
     The present invention may be modified in various forms, for example, the air cleaner element may be installed in the air cleaner case as shown in FIG. 12 or FIG. 13. FIGS. 12 and 13 show cross-sections which are similar to those shown in FIGS. 5 and 10. An air cleaner 210 shown in FIG. 12 has an air cleaner element 214 which includes an air-intake port 212 integrally formed with the air cleaner element 214. The air cleaner element 214 is formed in a cylindrical shape which stretches or contracts in its axial direction. The air cleaner element 214 including the air-intake port 212 is installed horizontally in the air cleaner case from a right side wall of the air cleaner case. The air cleaner element 214 is easily installed by contracting its axial length which is in turn expanded by air pressure when the module is in use. 
     FIG. 13 shows another modification, in which a cylindrical duct 320 is horizontally fixed to an air-intake port 312, and an air cleaner element 314 is inserted in the cylindrical duct 320. The air cleaner element 314 has a similar shape as the air cleaner element 214, and its axial length is flexible so that it is contracted when installed and expanded when used. It is not essential, however, to form the air cleaner elements 214 and 314 to be flexible in the axial length. They may be made in a solid form having a fixed axial length. 
     Though the number of the manifold pipes is four in the embodiments above described, it is not limited to four, but it is varied according to the number of cylinders of the engine on which the air-intake module is mounted. It is not essential to make the length of each manifold pipe equal, but it may be modified to best fit the engine. 
     The present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form and detail may be made therein without departing from the scope of the invention as defined in the appended claims.