Abstract:
The present invention relates to an arrangement for internal combustion engines of the piston engine type having at least one row of cylinders, comprising at least one fuel injector for each cylinder and at least one intake manifold for admission of air to the cylinders. The inlets of the fuel injectors are connected to a fuel channel arranged in the intake manifold.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This is a continuation patent application of International Application Number PCT/SE00/00031 filed Jan. 12, 2000 that designates the United States. The full disclosure of said application, in its entirety, is hereby expressly incorporated by reference into the present application. 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    1. Technical Field  
           [0003]    The present invention relates to an arrangement for internal combustion engines of the piston engine type having at least one row of cylinders. The arrangement has at least one fuel injector for each cylinder and at least one intake manifold for admission of air to the cylinders.  
           [0004]    2. Background Art  
           [0005]    Nearly all vehicles are equipped with an internal combustion engine or diesel engine. Today&#39;s internal combustion engines, which run on gasoline, are provided with fuel injectors in contrast to carburetors for older engines. This is due to the increasingly stringent requirements regarding exhaust gas. An engine that has become more common recently is one having injectors that injects the fuel directly into the cylinder, known as direct injection. This type of engine permits lean running. However, direct injection engines have a construction-related problem in finding room on the engine&#39;s cylinder head for the injectors and their admission lines, together with intake manifolds and other lines arranged around the cylinder head. The intake manifolds themselves take up a substantial amount of room, requiring perhaps several ports per cylinder, exhaust gas recirculation (“EGR”) inlets, valves, and pipes with selectable airways. In this context, use is often made of a fuel pipe system having a feed pipe to the side of the engine and narrow lines from the feed pipe to the injectors. These are relatively costly constructions since the demands on compactness and strength in this environment are high. Direct injection is also found on diesel engines, which have similar problems.  
         SUMMARY OF INVENTION  
         [0006]    The present invention provides a solution to the above problems. In the invention, the inlets of the fuel injectors are connected to a fuel channel arranged in the intake manifold. The fuel channel is advantageously integrated in the intake manifold construction, with the inlets of the injectors preferably connected to openings adapted for them in the intake manifold.  
           [0007]    A particularly advantageous embodiment has the intake manifold divided into two parts. The first part accommodates the fuel channel and the attachments to the fuel injectors, and the second part constitutes the rest of the intake system with, inter alia, the pipes. At the end facing away from the engine, the intake manifold may be designed with an attachment to an air-cleaning system or the like. One advantage of dividing an intake manifold in two is that the first part can be made of a material well suited for the special material treatment that is needed, while the other part can be made of a material with lower requirements, i.e., a less expensive material. The first part may be coupled to the fuel injectors with their associated demands, such as leak tightness and, therefore, surface fineness in the openings where the injectors are attached. The handling of the work pieces during material treatment is also made easier by the fact that the part which is treated is smaller than a complete intake manifold, e.g., if the material is to be treated in a furnace. It is also expedient to accommodate in the first part valves for swirl effect, since assembly is simpler. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]    The invention will be described and explained below with reference to the figures shown in the attached drawings, in which:  
         [0009]    [0009]FIG. 1 illustrates a perspective view of a cylinder head of an engine according to the invention, with attached fuel injectors;  
         [0010]    [0010]FIG. 2 illustrates a perspective view of a first intake manifold part from the side intended to be connected to the intake side of the cylinder head and the fuel injectors;  
         [0011]    [0011]FIG. 3 shows the same cylinder head as in FIG. 1, with an attached first portion of an intake manifold according to FIG. 2;  
         [0012]    [0012]FIG. 4 shows a cross-section view through a fuel injector and its connection to a fuel channel in the intake manifold; and  
         [0013]    [0013]FIG. 5 again shows the same cylinder head as in FIGS. 1 and 3, but with a complete intake manifold according to the invention fitted on it. 
     
    
     DETAILED DESCRIPTION  
       [0014]    [0014]FIG. 1 is a perspective view of a conventional cylinder head  1  intended for a customary double overhead camshaft. The valve cap, camshafts, valve mechanisms and their associated bearings and bearing covers have been omitted since they do not pertain to the invention.  
         [0015]    The cylinder head  1  is intended for an engine with five cylinders. However, the invention should not be interpreted as being limited to five cylinders. Each cylinder has two inlet ports for air (concealed in the figure), which are connected to an adapter part  3  that belongs to the intake manifold construction and extend along the side  2  of the cylinder head. The adapter part  3  has inlet channels  4 ,  5 ,  6 ,  7  and  8  that are connected in pairs to the inlet ports of the engine. A fuel injector  9  is mounted between the channels in each pair of inlet channels, (here, a total of five fuel injectors). The fuel injectors  9 , which may be any known type available on the market, have an electrical connection  10  for a control signal and a circular-cylindrical fuel inlet  11 . Depending on the desired injection angle in the cylinder, the fuel injectors  9  and their inlets  11  have a direction that is angled in relation to the cylinder head&#39;s connection plane to the engine and the main axis of the engine cylinders. On the cylinder head  1  shown in the figure, the connection plane faces downwards and is indicated by an arrow labeled  12 .  
         [0016]    Along the engine, the adapter part  3  is designed with first and second connection planes  13  and  14 . The first plane  13  is connected to a corresponding plane on the side  2  of the cylinder head  1  so that the cylinder inlet ports opening out in the side of the cylinder head connect to and continue in the inlet channels  4 - 8 . The second connection plane  14  is arranged at an angle to the first connection plane  13  such that the connection plane  14  lies at right angles to the direction of the fuel inlet  11 .  
         [0017]    [0017]FIG. 2 illustrates a first, inner part  15   a  of an intake manifold  15  whose side  16  shown in the figure has one or more inlet openings  17  and one or more fuel holes  18  corresponding to the inlet channels  4 - 8  of the second connection plane  14  and the fuel inlets  11  of the injectors  9 . The fuel holes  18  are in direct communication with a fuel channel  19  (shown diagrammatically) that is integrated in the part  15   a  and that in turn receives fuel from a feed line (not shown) via a fuel inlet  20 .  
         [0018]    [0018]FIG. 3 shows the first part  15   a  of the intake manifold  15  mounted on the adapter  3 . The inlet openings  17  are arranged in such a way that they have a direct continuation in the inlet channels  4 - 8 . On that side of the intake manifold part  15   a  directed towards and connected to the adapter part  3 , the fuel inlets  11  of the fuel injectors  9  are connected to corresponding fuel holes  18  in the part  15   a.  By virtue of the fact that the connection plane  14  is at right angles to the direction of the fuel inlets  11  on the injectors  9 , there is no uneven loading of the injectors  9  from the intake manifold  15   a.  Normally, the injectors  9  are secured to the cylinder head  1  by bolts or in a similar manner. However, it is also possible for them to be held secure solely by having the intake manifold  15   a  lie on the outside via support surfaces (not shown) that are arranged on the bottom of the fuel holes  18  and that bear against the fuel inlets  11  of the injectors. A pressure sensor  28  and safety valve  29  for the fuel are also connected to the part  15   a.    
         [0019]    [0019]FIG. 4 shows a cross-section of a fuel injector  9  and its attachment to the intake manifold part  15   a.  An extension part  21  with a portion  22  inserted into a fuel hole  18  is connected coaxially to the fuel inlets  11  of the injectors. Arranged between the extension part  21  and the outside of the inlet  11  of the fuel injector, and between the portion  22  of the extension part and the inside of the fuel hole  18  of the intake manifold part  15   a,  are sealing rings  23  and  24 , respectively. This construction affords a tolerance-absorbing effect between the inlets  11  of the fuel injectors and the fuel holes  18  in the intake manifold  15   a.  The figure also shows an inlet port  17 , indicated by broken lines. A swirl valve  25  is shown diagrammatically in the port  17 . The swirl valve  25  can be controlled in a known manner via a diagrammatically represented control rod  26  in a rod hole  27  (see, FIG. 5). Swirl valves are arranged in one of the two inlet ports  17  belonging to each cylinder. A bolthole  28  for attachment of the adapter part  3  is also shown.  
         [0020]    The intake manifold  15  is completed in FIG. 5 by an outer part  15   b  that comprises pipes  30 , one pair for each cylinder, and a connection  31  to the air supply system, valve housing and similar components normally belonging to a car engine.  
         [0021]    The part  15   a  of the intake manifold  15  connected to the fuel injectors  9  must, in the fuel holes  18  connected to the inlets  11  of the fuel injectors  9 , have a surface fineness that ensures that no leakage occurs. It is also important that the walls in the intake manifold  15  withstand the fuel pressure while at the same time are as thin as possible in order to take up the least possible space and have the lowest possible weight. A suitable material for the pipe is aluminum, which can be chilled-cast. Thixocasting can also be used, and hot isostatic pressing (“HiPping”) to have the pores pressed together. In these treatments it is a great advantage that the work pieces are not unnecessarily large and unwieldy. In addition, a less expensive material can be chosen for the part  15   b,  which does not need to meet stringent specifications.  
         [0022]    Other embodiments of the present invention include, for example, integrating the intake manifold into a single piece comprising the adapter  3 , the inner part  15   a  and the outer part  15   b  in a design with the fuel holes  18  arranged directly on the inlets  11  of the fuel injectors. It is also possible to integrate only the adapter part  3  and the inner part  15   a,  and it is likewise possible for the adapter part to be integrated in the cylinder head, i.e., the cylinder head is designed with a connection plane  2  at right angles to the direction of the inlets of the fuel injectors.  
         [0023]    While there has been disclosed effective and efficient embodiments of the invention using specific terms, it should be well understood that the invention is not limited to such embodiments as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.