Abstract:
The present invention relates to an optical engine comprising a cylinder head of an industrial engine and a transparent cylinder. According to the invention, the transparent cylinder is tightly applied to the cylinder head by pneumatic means, a jack for example, allowing easy dismantling and cleaning of the cylinder. Furthermore, the industrial cylinder head is mounted on a support secured to the frame of the &lt;&lt;engine bottom &gt;&gt; by jacks or equivalent means, at least one of these means being pneumatic for opening the engine.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a single-cylinder engine suited for optical measurements on the parameters of the combustion that takes place in the chamber provided by a cylinder head, a transparent cylinder and a piston.  
           [0002]    This type of engine is of great interest for visualizing what takes place in a combustion chamber of an engine, considering the fuel supply means, the exhaust means, the type of fuel, the engine load, or other parameters affecting the running conditions of the combustion engine. The ignition mode of the fuel can in particular be observed on a real-time basis.  
         BACKGROUND OF THE INVENTION  
         [0003]    Test engines equipped with cylinders having portholes made of a transparent material for visual observation are already known, but they notably present the drawback of being fragile, with mounting, seal difficulties, problems of adaptability to different types of cylinder head, difficulties in cleaning the observation means that are quickly covered with carbon deposits due to combustion.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides advantageous solutions in relation to the prior art and thus relates to an optical test engine comprising a cylinder made of a transparent material, a piston cooperating with the cylinder, a cylinder head on top of the cylinder so as to form a sealed combustion chamber. The cylinder is applied to the plane of the cylinder head by an annular jack whose travel allows access to the inside of said chamber and the cylinder head is secured to a frame by means of a support mounted on four columns consisting of guides that slide longitudinally.  
           [0005]    The annular jack can be pneumatic.  
           [0006]    The columns can comprise a rod guided by balls, or equivalent means.  
           [0007]    The travel of the columns and the travel of the annular jack can be determined to allow dismantling of the cylinder and of the piston.  
           [0008]    The cylinder head can be a cylinder head of an industrial engine, fastened to the support. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0009]    Other features and advantages of the present invention will be clear from reading the description hereafter of a non limitative example, with reference to the accompanying drawings wherein:  
         [0010]    [0010]FIG. 1 diagrammatically shows, in cross-sectional view, the optical engine according to the invention, in running position,  
         [0011]    [0011]FIG. 2 shows, also in cross-sectional view, the same engine in &lt;&lt;open &gt;&gt; position allowing access to the cylinder and/or to the piston,  
         [0012]    [0012]FIGS. 3 and 3A illustrate a system intended for quick locking of the cylinder head.  
     
    
     DETAILED DESCRIPTION  
       [0013]    In FIG. 1, reference number  1  refers to an assembly referred to as &lt;&lt;engine bottom &gt;&gt; and reference number  2  refers to an assembly consisting of the cylinder head and the combustion chamber.  
         [0014]    The &lt;&lt;engine bottom&gt;&gt; assembly is conventional and comprises a crankcase  3  wherein a crankshaft  4  is connected to a connecting rod  5  and to a crosshead  6  subjected to a reciprocating motion. A device intended to drive and/or to brake the rotation of the crankshaft is not shown here since it is of conventional design and known to the man skilled in the art. Crosshead  6  is extended by a crosspiece  7  at the end of which a piston  8  is fastened. The crosspiece is manufactured in such a way that a mirror  9  can be arranged in line with piston  8  so that an observation means  10 , a camera for example, visualizes and/or records, through a transparent wall of piston  8 , the phenomena that take place within the combustion chamber.  
         [0015]    Assembly  2  consists of a cylinder head diagrammatically represented by element  11 . What is referred to as a cylinder head here is all the means that define a combustion chamber, supply and exhaust ports, corresponding supply and exhaust means: valves, injection means, etc. This assembly also comprises the valve mechanization means, camshafts or equivalent means. The means for driving the camshaft are not shown here, but they are known to the man skilled in the art.  
         [0016]    The cylinder head is fastened to a support  12 , for example a sufficiently stiff metal plate. Support  12  is connected to &lt;&lt;engine bottom&gt;&gt;  1 , and more precisely to upper frame  13 , by columns  14 , preferably four, determined to be stiff enough laterally while allowing vertical longitudinal sliding for lifting the cylinder head in relation to the transparent cylinder. These four columns can comprise ball guides that limit the side play while allowing a longitudinal travel that can range, for example, between 5 and 20 cm.  
         [0017]    In order to move cylinder head  11  on its support  12  by means of guides  14 , at least one pneumatic jack  15  is fastened to frame  13 , the rod being fastened to support  12 . Of course, said columns  14  are immobilized by locking means when the engine is running (engine closed). Quick locking and unlocking means are preferably used so as to allow fast opening of the engine by means of pneumatic jack  15 . Long-thread screws and nuts cooperating with split crosspieces can for example be used, which can thus be removed without requiring complete removal of the nut. Other quick fastening means can also be used without departing from the scope of the present invention. Hydraulic jacks maintained locked under pressure can be used.  
         [0018]    Frame  13  comprises a special layout receiving a pneumatic jack  16 . An annular part  17  forms a piston that moves towards the cylinder head by applying a pressure, preferably pneumatic, in chamber  18 . The upper part of annular piston  17  is machined to receive the base of a cylinder  20  made of a transparent material quartz for example.  
         [0019]    [0019]FIG. 2 shows the same section as in FIG. 1, but the engine is &lt;&lt;open &gt;&gt;, thus allowing access to piston  8 , to transparent cylinder  20  and to the lower plane of cylinder head  11 . There are two displacements that complement one another and add up: the recoil of annular piston  17  that supports transparent cylinder  20 , the lift of the cylinder head through displacement of its support  12  after unlocking jacks  14 , the actuation of pneumatic jack  15  and the coming out of rod  21 .  
         [0020]    [0020]FIG. 3 shows an example of quick fastening of the cylinder head and of support  12  to frame  13  of the &lt;&lt;engine bottom &gt;&gt;. Column  14  consists of a rod  22  fastened to support plate  12  and a cylinder fastened to frame  13 . An assembly of bearing means  24 , ball bearing for example, allows longitudinal displacement with a minimum side play. Rod  22  runs through frame  13  and is ended by a thread  25  for locking by means of a nut  26 . A crosspiece  27  of length l allows, after its has been removed, support  12  to be moved away from frame  13  by a distance at most equal to l. FIG. 3A is a cross-sectional view of crosspiece  27  and rod  22 . The U shape of the crosspiece allows, as soon as nut  25  is unlocked, removal by lateral displacement and the cylinder head can be freely moved away from the frame, and the engine can thus be opened.  
         [0021]    It is thus clear that the present optical engine can be (partly) opened immediately simply by actuating pneumatic jack  17 . It is thus possible to have access to the inside of the cylinder in order to clean it and to continue optical observations through the transparent cylinder.  
         [0022]    Another important advantage, due to the structure of the present engine, is the fact that a cylinder head of an industrial engine can be used practically directly. In fact, the adjustment possibility provided by the column mounting of the plate supporting the cylinder head does not require design and manufacture of a mounting specific to each type of cylinder head (or even manufacture of a special test cylinder head). In the case of a multi-cylinder engine, the present optical engine is mounted on the location of one of the combustion chambers, the various cooling, intake and exhaust pipes that communicate with the other three cylinder heads being sealed so that the industrial cylinder head is independent and usable on a single-cylinder basis by cooperating with the transparent single cylinder.  
         [0023]    Other advantages of the present invention can be mentioned:  
         [0024]    easy replacement of the cylinder,  
         [0025]    good control of the bearing area of the cylinder on the joint plane of the cylinder head for sealing by means of the pneumatic annular jack,  
         [0026]    adaptability to different types of cylinder head,  
         [0027]    easy replacement of the lower and upper piston,  
         [0028]    great rigidity of the assembly provided by the columns with ball guides,  
         [0029]    adaptability of this engine to differents types of bore and travel,  
         [0030]    it is not necessary to dismantle the flexible hoses of the cylinder head cooling and lubrication systems to &lt;&lt;open &gt;&gt; the engine according to the invention.