Abstract:
The injection speed of the injection valves in an internal combustion engine is increased by using a single injection valve configured to carry out multiple fuel injections and combustions per rotation cycle. The single-valve propulsion thermal reactor has a casing with upper and lower walls consecutively defining a sleeve for taking in a pressurized air flow, a combustion chamber, and a gas discharge nozzle. The thermal reactor has a single injection valve to inject fresh gas into the combustion chamber, and at least one valve to exhaust burnt gases, which extends about transverse axes. The valves are cylindrical and have multiple surfaces which have a circular cross-section and are separated by facets that define, by a rotation of the valves, the intake and discharge ports for the gases. Preferably, a thermal ignition tank is built into the combustion chamber.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a single-valve propulsion method with multiple injection and multiple combustions per rotation cycle, particularly in the jet engines used in the aeronautical field, and more particularly still, reactors operating on the Humphrey thermodynamic cycle using constant-volume combustion of a mixture of compressed air and of fuel. The invention also relates to an engine referred to as a thermoreactor operating on this method. In the present text, the qualifier “multiple” means “at least equal to three”. 
         [0002]    The invention may also apply to any type of internal combustion engine operating on a thermodynamic cycle of the pulsed type, for example motor vehicle engines, whether these operate at constant volume or at constant pressure in the combustion chamber. 
         [0003]    The key benefit of the Humphrey cycle is that it makes more efficient use of the energy that the fuels can supply by performing combustion at constant volume followed by complete expansion of the burnt gases thus producing high levels of kinetic energy. Depending on the type of application, the reactor will produce power by driving a turbine, or alternatively will produce thrust directly. Reactors performing combustion at constant volume, also referred to as “thermoreactors”, therefore offer decisive advantages over turbomachines operating on a constant-pressure combustion, notably in terms of compactness, allowing them to be housed in the wings of an aircraft—in terms of mass, thrust and thermodynamic efficiency (with fuel consumption savings in excess of 10%). 
       PRIOR ART 
       [0004]    Combustion in thermoreactors is of the pulsed type whereas combustion in present-day constant-pressure turbomachines is continuous. Turbomachines with multiple thermoreactors are described in greater detail for example in patent document FR 2 945 316. In general, each thermoreactor comprises at least a compressor, at least a nozzle, and a combustion chamber connected to the compressor and to the nozzle by two sets of valves, injection and ejection valves respectively. 
         [0005]    Each combustion cycle is conventionally made up of three phases: a phase of admitting or injecting a preformed mixture of compressed air and of fuel, a phase of actual combustion of this mixture of gas by controlled emission, and a phase of expansion with ejection of the burnt gases. The thermoreactors operate in parallel and each thermoreactor is phase-shifted so that during one and the same combustion cycle, the thermoreactors cover all of the phases of this cycle. 
         [0006]    The rotation of the valves is driven by suitable electric motors in a synchronized manner so that when a premixture of fresh gas is introduced into the combustion chamber by a throat formed between two injection valves (admission phase), the two ejection valves close the gas outlet. Similarly, after the combustion of the mixture, the injection valves close the admission to the combustion chamber and the ejection valves form a throat for letting the gases out during the expansion of the burnt gases (ejection phase). 
         [0007]    The valves have suitable cylindrical shapes of elongate or oblong external cross section and are positioned so that, as they rotate in a coordinated manner, they are able to form connecting throats which are successively opened and closed twice in each rotary cycle. In other words, each cyclic rotation of one set of valves covers two combustion cycles. 
       SUMMARY OF THE INVENTION 
       [0008]    This type of thermoreactor is also a particular benefit if it could be miniaturized. Specifically, reducing the dimensions and therefore the volume of such thermoreactors leads to a reduction in their mass and bulk. As a result, applications to the field of space travel are conceivable, as are applications to other domains (scale models, experiments on new fuels, etc.). 
         [0009]    However, a miniaturization ratio of the order of 5 to 10—making it possible for example to come down from a combustion chamber volume of one liter to 100 or 200 cm 3 —leads to a corresponding decrease in the propulsion power supplied by the thermoreactor, all other things being equal. If the power is to be maintained, then the rate of injection of the valves needs to be significantly increased, leading to great problems with valve stability and sealing between these valves and the casing of the combustion chamber whereas the rate at which the post-combustion gases are ejected—which is dependent only on the pressure and temperature conditions—remains substantially constant. The invention seeks to alleviate these problems by providing the ability to use a single injection valve of special shape allowing several injections of fuel and combustions to be performed per rotation cycle of these valves. 
         [0010]    More specifically, one subject of the present invention is a single-valve propulsion method with multiple injections and multiple combustions per rotation cycle, comprising, per combustion cycle, a phase of admitting premixed fresh gases as input into a combustion chamber, a phase of actually combusting these gases in the body of the combustion chamber, and a phase of discharging the burnt gases as output from this combustion chamber. In this method, at least three constant-volume combustion cycles are performed per complete rotation cycle of multiple shapings able to form access apertures for admitting the mixture of fresh gases into the combustion chamber for a determined duration. These injection shapings follow on from one another uniformly in each constant-volume combustion cycle by rotation about a single transverse axis. Each of these shapings injects substantially the same quantity of premixture of fresh gases into the combustion chamber, this quantity being determined by the geometry and rotational speed of the shapings so as to establish an optimal pressure in the combustion chamber. Such an optimum pressure maximizes turbomachine performance. 
         [0011]    According to some preferred embodiments: 
         [0012]    at the end of each combustion cycle, a storage, preferably incorporated into the combustion chamber is effected by bleeding off high-pressure and high-temperature burnt gases and then, after new fresh gases from the next combustion cycle have been admitted, the high-pressure hot gases bled off from the previous combustion cycle mix with the low-pressure fresh gases by reinjection into the combustion chamber brought about by a pressure difference and triggering the ignition of the fresh gases; 
         [0013]    the bleeding-off of burnt gases is carried out via the shapings during intervals of time in which these shapings face toward the inside of the combustion chamber; 
         [0014]    the bleeding-off and reinjection of the bled-off gases are performed by two similar operations according to movement of the bled-off gases circulating in opposite directions; 
         [0015]    the storage is common to at least two simultaneous bleed-off operations followed by two simultaneous reinjection operations in the combustion chamber; 
         [0016]    an injection of fuel is incorporated into a stream of compressed air upstream of the combustion chamber to form the premixture of fresh gases introduced into the combustion chamber during the admission phase of each combustion cycle, the fuel being injected into the stream of air via rotating ports which open periodically and in a ducted manner into said stream in a manner synchronized with the duration of the admission phase; 
         [0017]    during the phase of discharging the burnt gases of each combustion cycle which follows the actual combustion phase, one of the multiple ejection shapings form an access aperture for discharging the burnt gases from the combustion chamber, the ejection shapings following on uniformly from one another by rotation about at least one single transverse axis to form the discharge access apertures during the same duration as the duration for which the admission access apertures are formed by the injection shapings; 
         [0018]    a cooling of the burnt gases is carried out by an exchange of heat as close as possible to the ejection shapings; 
         [0019]    the rotation cycles of the fuel injection ports in the stream of air, of the injection shapings for injecting the premixture of fresh gases into the combustion chamber and of the discharge shapings for discharging the burnt gases are synchronized so that no fuel is injected into the stream of air nor is any access aperture providing admission to the combustion chamber formed during the combustion phase, and in which the phases of admitting and ejecting gases into and from the combustion chamber have a period of overlap during which the fresh gases entering the combustion chamber via the admission access apertures discharge the remaining burnt gases from the previous combustion cycle via the discharge access apertures. 
         [0020]    The invention also relates to a thermoreactor able to implement the above method. Such a thermoreactor comprises a casing of parallelepipedal overall shape with an upper wall and a lower wall successively forming, from upstream to downstream, an inlet sleeve for a stream of compressed air, a combustion chamber and a gas discharge nozzle. This thermoreactor also comprises a single injection valve for injecting fresh gases into the combustion chamber and at least one ejection valve for ejecting the burnt gases extending about transverse axes for respectively separating the sleeve from the combustion chamber and separating the combustion chamber from the nozzle. The valves are cylindrical and have multiple faces of circular cross section uniformly distributed and separated by cut facets forming, by rotation of the valves, access apertures for admitting and discharging the gases of heights that can vary periodically between open to the maximum and fully closed when the valves are driven in synchronized rotation by drive means about the transverse axes. 
         [0021]    According to some preferred embodiments: 
         [0022]    an inbuilt thermal ignition tank extends transversely in the combustion chamber near the injection valve and is provided with ducts with transverse openings arranged in such a way as to allow gases to circulate from the tank to the combustion chamber and from the combustion chamber to the tank via the cut facets during earlier time intervals and completing the combustion of the fresh gases; 
         [0023]    the valves have at least three and at most four cut facets and circular faces; 
         [0024]    each cut facet forms a recess of concave overall shape having a groove bottom of a shape chosen between a flat face, a face with a single concave curvature, a face with a double curvature and a face with two concave curvatures connected by a convex curvature; 
         [0025]    when the injection and ejection valves have three cut facets uniformly distributed between three circular faces, the axes of rotation of these valves are located in the combustion chamber and in the discharge nozzle; 
         [0026]    the facets of the injection valve extend over a width substantially equal to that of the chords of the circular faces and the facets of the ejection valve extend over a width substantially greater than that of the chords of the circular faces; 
         [0027]    a fuel injector is incorporated into the inlet sleeve for the stream of compressed air so as to form a premixture of fresh gases to be introduced into the combustion chamber during the admission phase of each combustion cycle, the injector comprising a transverse cylindrical injection body punctured by at least two transverse ports and a transverse outer partially enclosing the cylindrical injection body and forming at least two ducts opening via transverse slits into the sleeve; in such conditions, when the cylindrical injection body is given a rotational movement synchronized with the rotation of the injection valve for the duration of the admission phases, the fuel is periodically injected into the stream of air in order to form an air/fuel premixture of fresh gases in the sleeve when the rotating ports are in communication with the ducts and the access apertures providing admission to the combustion chamber are formed; 
         [0028]    the fuel injector is located close to the injection valve so that the air/fuel premixture of fresh gases is formed as close as possible to the access apertures providing admission to the combustion chamber while at the same time remaining compatible with the time taken for the premixture to vaporize completely; 
         [0029]    at least one cooling pipe for the burnt gases, in which pipe a heat-transfer fluid circulates, is located as close as possible to the ejection valve; 
         [0030]    the cooling pipe or pipes is or are chosen from an upstream shield located in the combustion chamber, a pipe internal to the ejection valve and centered on the axis of rotation thereof and/or a downstream shield located in the gas discharge nozzle; 
         [0031]    a control unit synchronizes the speeds at which the fuel injector and the admission and ejection valves are driven so that the injection of fuel into the sleeve is synchronized with the formation of the access apertures for admitting the fresh gases via the injection valve into the combustion chamber, said valves rotating at the same speed so that the admission and discharge access apertures close at the same time in order to achieve constant-volume combustion. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0032]    Other features and advantages of the present invention will become apparent from reading detailed nonlimiting embodiments thereof, with reference to the attached figures which, respectively, depict: 
           [0033]      FIG. 1 : a view in longitudinal section of one example of the thermoreactor according to the invention comprising an injection valve with three bucket-shaped recesses and an ejection valve with three straight cut facets; 
           [0034]      FIG. 2 : a partial longitudinal section view of the example of the thermoreactor of  FIG. 1 , with an ejection valve which has three recesses; 
           [0035]      FIGS. 3   a  and  3   b : perspective views of the injection valve in connection with the inbuilt ignition tank, of the injection valve and of the ejection valve taken out of their context; 
           [0036]      FIG. 4 : a perspective view of the embodiment of the thermoreactor according to  FIG. 1  equipped with injection and ejection valves that have asymmetric recesses; 
           [0037]      FIG. 5 : a view in section of one example of an injection or ejection valve with four recesses; and 
           [0038]      FIGS. 6   a  to  6   d : cross-sectional schematics of the embodiment of the thermoreactor according to  FIG. 1  according to the various phases which follow on from one another during a combustion cycle: admission of fresh gases ( FIG. 6   a ), ignition of these gases ( FIG. 6   b ), end of combustion ( FIG. 6   c ), then discharge of burnt gases ( FIG. 6   d ). 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    In this text, the qualifiers “upstream” and “downstream” relate on the whole to the direction in which the gases travel between arriving and being discharged. The qualifiers “upper” and “lower” refer to the location of an element with respect to the median plane of the thermoreactor in its standard configuration of use, and “internal” refers to the location of an element oriented on the side of this median plane. The term “transverse” denotes, in the median plane, the direction normal to the longitudinal axis of the thermoreactor. 
         [0040]    With reference to the view in longitudinal section of  FIG. 1 , an example of a thermoreactor  1  according to the invention comprises a casing  20  of rectangular overall shape in cross section and parallelepipedal in extension in space, with an upper wall  20   s  and a lower wall  20   i.  As an alternative, the casing may have an elliptical contour in order to spread mechanical loads more evenly. Such a casing  20  has a median plane of symmetry Pm. This casing  20  forms, from upstream to downstream according to the direction in which the gases progress: an inlet sleeve  2  for a stream of compressed air Fa upstream from a compressor (not depicted), a combustion chamber for the fresh gases  4  and a discharge nozzle  6  for the burnt gases. 
         [0041]    The air intake sleeve  2 , the combustion chamber  4  and the discharge nozzle  6  are delimited by radial projections  10 A to  10 D situated facing one another in pairs substantially at right angles to the median plane Pm. In this way, the protrusions  10 A and  10 C on the one hand, and  10 B and  10 D on the other, are formed transversely and, respectively, on the internal faces  21   s  and  21   i  of the upper  20   s  and lower  20   i  walls of the casing  20  respectively. An injection valve  3  for injecting fresh gases into the combustion chamber  4  and an ejection valve  5  for ejecting burnt gases to the nozzle  6  extend transversely in order respectively to separate the sleeve  2  from the combustion chamber  4  and the combustion chamber  4  from the nozzle  6 . The valves  3  and  5  are cylindrical, with a base that is circular overall, and extend transversely about axes of rotation X′X and Y′Y. These axes of rotation are located in the median plane Pm and, more particularly, respectively in the combustion chamber  4  and in the discharge nozzle  6 . The opposing radial protrusions  10 A- 10 B and  10 C- 10 D thus periodically come into contact with the valves  3  and  5  in each combustion cycle, respectively subtending angles  3 A and  5 A substantially equal to 120°. 
         [0042]    Three circular faces are uniformly distributed on the circumference of the valves  3  and  5 , these mainly being the circular faces  31 ,  33  and  35  in the case of the injection valve  3 , and the circular faces  51 ,  53  and  55  in the case of the ejection valve  5 . These circular faces are separated, on a main part of their transverse extent, by cut-facet shapings forming recesses  32 ,  34  and  36  in the case of the injection valve  3 , and planar faces  52 ,  54  and  56  in the case of the ejection valve  5 . The presence of recesses in the injection valve  3  means that the extent to which the combustion chamber  4  is filled with premixture gases can be increased significantly by comparison with planar cut facets. 
         [0043]    More particularly, the recesses  32 ,  34  and  36  of the injection valve  3  extend over a width substantially equal to that of the chords of the circular faces  31 ,  33  and  35  to encourage uniform admission of fresh gases to the combustion chamber  4 . Further, the faces  52 ,  54  and  56  of the ejection valve  5  extend over a width substantially greater than that of the chords of the circular faces  51 ,  53  and  55  to encourage the discharging of gases to the nozzle  6 . 
         [0044]    In the example illustrated, the recesses  32 ,  34  and  36  of the injection valve  3  have a groove bottom  3 F that is convex overall, with having two convex curvatures connected by a central concave curvature. This configuration encourages reliable routing of a given quantity of premixture into the combustion chamber  4 . As explained hereinbelow (with reference to  FIGS. 6   a  to  6   d ), these cut facets  32 ,  34 ,  36 ,  52 ,  54 ,  56  will thus form an inlet access aperture and an outlet access aperture respectively for admitting fresh gases and letting out burnt gases, by synchronous rotation of the X′X and Y′Y transverse axes of the valves  3  and  5 . 
         [0045]    The thermoreactor  1  is also equipped with a fuel injector  7 , with an ignition tank  8  and with cooling pipes  9  to  11 . 
         [0046]    The fuel injector  7  is incorporated into the inlet sleeve  2  for the arrival of the stream of compressed air Fa, to form a premixture of fresh gases. This injector  7  comprises a transverse cylindrical injection body  70  punctured by two transverse ports  7   a  and  7   b.  A transverse outer  71  partially encloses the cylindrical body  70 . This outer  71  is made up of a convex wall  71   a  and of a concave wall  71   b,  these walls facing upstream so that the concave wall  7  lb externally conforms to the shape of the circular envelope  3 E (in dotted line) of the injection valve  3 . The walls  71   a  and  71   b  between them form two ducts  71   c  and  71   d  which start on the injection body  70  and extend substantially radially on each side of the injection body  70  with respect to the median plane Pm. 
         [0047]    At their start, the ducts  71   c  and  71   d  have a width substantially equal to the width of the ports  7   a  and  7   b  of the body  70  and open via transverse injection slits  72   c  and  72   d  in the sleeve  2 . Advantageously, these fuel-injection slits are located near the injection valve  3  so that the air/fuel premixture forms as close as possible to the intake into the combustion chamber  4 . The distance between the injector and the aperture providing access to the combustion chamber is determined so that the premixture will be able to vaporize completely. 
         [0048]    As for the inbuilt thermal ignition tank  8 , that also extends transversely near the injection valve  3  but in the combustion chamber  4 . This tank  8  has two walls  8   a  and  8   b  having shapes that are convex-concave overall and face downstream. These walls  8   a  and  8   b  form ducts  8   c  and  8   d  which, at their end, have transverse openings  8   e  and  8   f  onto the chamber  4 . These openings are located as close as possible to the injection valve  3  so as to encourage double circulation of the gases between the tank  8  and the combustion chamber  4  via the recesses  32 ,  34  and  36 . These circulations occur during the intervals of time in which the recesses  32 ,  34  and  36  substantially face the transverse openings  8   e  and  8   f  of the tank  8  (see hereinafter with reference to  FIGS. 5   b  and  5   c  which illustrate ignition and end of combustion of the gases of one combustion cycle). 
         [0049]    Cooling pipes are provided where the hot gases originating from the combustion are discharged. Circulating through these cooling pipes, which are located as close as possible to the ejection valve  5 , is a heat-transfer fluid which performs heat exchanges. One of these cooling pipes takes the form of an upstream shield  9 , located in the combustion chamber  4 . This shield  9  has a structure made up of two transverse walls  9   a  and  9   b  joined at their ends, with a respectively convex/concave curvature facing upstream. This being so, the concave wall  9   b  extends as close as possible to the circular envelope  5 E (in dotted line) of the ejection valve  5 . 
         [0050]    Another shield  10 , this one downstream of the ejection valve  5 , is incorporated into the discharge nozzle  6 . It too takes the form of two walls  10   a  and  10   b  with curvatures facing downstream, these respectively being concave and convex. The concave wall  10   a  extends as close as possible to the circular envelope  5 E of the ejection valve  5 . 
         [0051]    Advantageously, the pipe  11  internal to the ejection valve  5  and centered on the axis of rotation Y′Y thereof also acts as a cooling pipe for the post-combustion gases through the circulation of a suitable heat-transfer fluid along this pipe  11 . 
         [0052]    A control unit  100  synchronizes the rotational speeds of the fuel injector  7  and of the injection  3  and ejection  5  valves so that the injection of fuel is brought about by the injection valve  3 . The valves  3  and  5  are controlled by the unit  100  to have the same rotational speed so as to close off accesses to the combustion chamber  4  for a determined duration so that constant-volume combustion can take place for this duration. 
         [0053]    An alternative form of ejection valve for the example thermoreactor  1  is illustrated by the view in part section of  FIG. 2 . In this view, an ejection valve  5 ′ with recesses  52 ′,  54 ′ and  56 ′ replaces the ejection valve of  FIG. 1  with cut facets formed of planar faces  52 ,  54  and  56 . The ejection valve  5 ′ adopts the profile shape of the convex overall recesses  32 ,  34  and  36  of the injection valve  3  of  FIG. 1 . The recesses  52 ′,  54 ′ and  56 ′ extend over a width substantially greater than that of the chords of the circular faces  51 ,  53  and  55 , in the example illustrated being twice as wide. The presence of recesses makes it possible significantly to increase the extent to which the burnt gases are ejected from the combustion chamber  4  into the nozzle  6 . 
         [0054]    The perspective views of  FIGS. 3   a  and  3   b  illustrate the transverse extensions of the injection  3  and ejection  5  valves parallel to the axes X′X and Y′Y in the median plane Pm—between the walls  20   s  and  20   i  of the casing  20 —and that of the inbuilt ignition tank  8 . It is particularly evident that the concave wall  8   a  of the tank  8  follows the external circular face  31  of the injection valve  3  and, therefore, over time, of all the circular faces  31 ,  33  and  35  of the valve  3  or, to put it another way, the circular envelope  3 E of said valve  3 . In addition, the recesses  32 ,  34  and  36  can be seen in perspective as forming buckets with a slightly domed bottom. 
         [0055]      FIG. 3   b  more specifically shows, at the end of the valves  3  and  5 , drive pullers  30  and  50  which accept a belt  12  able to ensure that the two valves  3  and  5  are synchronized. The injection valve  3  is rotationally driven by a geartrain connected with the shaft of an electric motor (not depicted). The assembly comprising pulleys—belt—geartrain constitutes drive means  200  controlled by the unit  100 . 
         [0056]    Reference is made to  FIG. 4  which illustrates a perspective view of the example of thermoreactor according to  FIGS. 1 and 2  with, as an alternative, injection  3 ′ and ejection  5 ″ valves which respectively have recesses  32 ′,  34 ′,  36 ′ and  52 ″,  54 ″ and  56 ″ of asymmetric shape. 
         [0057]    The thermoreactor  1 ′ of  FIG. 4  is the one depicted in  FIGS. 1 and 2  with the same casing  20  of walls  20   s  and  20   i,  the same injector  7  and the same cooling pipes  9  to  11 . The parts of sleeve  2  for the flow of air Fa, combustion chamber  4  for the fresh gases G 1  and nozzle  6  for discharging the burnt gases G 2  are also substantially identical. The thermoreactor differs therefrom via the thermal ignition tank  8 ′ which has two compartments  80   a  and  80   b  separated symmetrically by a partition  81  parallel to the median plane Pm. Such partitioning allows more uniform distribution of the hot gases G 2  that are to be stored. 
         [0058]    It also differs therefrom through the configuration of the recesses  32 ′,  34 ′,  36 ′ and  52 ″,  54 ″ and  56 ″ of the injection  3 ′ and ejection  5 ″ valves, which are in the form of buckets the curvature of which is concave overall. More specifically, the recesses  32 ′,  34 ′ and  36 ′ of the injection valve  3 ′ are just concave, and the recesses  52 ″,  54 ″ and  56 ″ of the ejection valve  5 ″ have an alternating convex/concave curvature. In other embodiments, the recesses of the injection valve have a double curvature and those of the ejection valve have just a concave curvature. 
         [0059]    In contrast with what has been depicted in  FIGS. 1 and 2 , the buckets no longer have a plane of symmetry: the groove bottoms  3 F′ and  5 F′ are offset toward the circular faces  33 ,  35 ,  31 ,  53 ,  55  and  51  which follow the respective recesses  32 ′,  34 ′,  36 ′,  52 ″,  54 ″ and  56 ″ in the direction of rotation of the valves  3 ′ and  5 ″ (in the direction of the arrows R 1  and R 2 ). This being so, the recuperation of fresh gases G 1  by the injection valve  3 ′ and of burnt gases G 2  by the ejection valve is optimized by the dynamics of the rotation of the valves. 
         [0060]    According to another embodiment, the view in cross section of  FIG. 5  illustrates an alternative valve  15  which may be an injection or ejection valve, with four circular faces  15   a ,  15   c,    15   e  and  15   g  distributed between four cut facets  15   b,    15   d,    15   f  and  15   h.  The cut facets take the form of convex recesses. Containers C 1  and C 2  located upstream and downstream of the valve  15  conform to the shape of the circular envelope  15 E (in dotted line) of the valve  15 . These containers with concave/convex curvature respectively represent a fuel injector and an inbuilt ignition tank, in the event that the valve  15  is an injection valve. These containers C 1  and C 2  represent cooling pipes when the valve  15  is used as an ejection valve. 
         [0061]    In order to describe a complete combustion cycle, the cross-sectional diagrams of  FIGS. 6   a  to  6   d  illustrate, in the example of thermoreactor  1  according to  FIG. 1 , the successive phases of injecting fuel with the admission of premixed fresh gases ( FIG. 6   a ), of igniting these gases to generate the start of combustion thereof ( FIG. 6   b ), the end of combustion with the storage of hot gases ( FIG. 6   c ), and the discharging of the burnt gases ( FIG. 6   d ). The diagrams are photographs fixing the instants during the various phases mentioned, which phases follow on periodically from one another with the synchronous rotation (arrows R 1  and R 2 ) of the injection and ejection valves  3  and  5  and of the cylindrical injection body  70  of the injector  7 . 
         [0062]    With reference to  FIG. 6   a , the ports  7   a  and  7   b  of the injection body  70  in synchronous rotation with the injection valve  3 , come into communication with the ducts  71   c  and  71   d  of the injector  7 . The fuel from the center of the injection body  70  then passes through the ports  7   a  and  7   b  to flow into the ducts  71   c  and  71   d.  An air-fuel premixture of fresh gases G 1  is formed by the injection of fuel (arrows F 1 ) into the compressed air inlet sleeve  2  (arrows Fa). To do that, the fuel leaves the ducts  71   c  and  71   d  via the slits  72   c  and  72   d  ( FIG. 1 ) to mix with the air in fine droplets. In this phase, the valves  3  and  5  are in the position for accessing the combustion chamber  4 , so as to allow the premixture G 1  to be admitted and the burnt gases G 2  to be exhausted. 
         [0063]    The premixture G 1  enters the combustion chamber  4  via access apertures A 1  formed between the ends of the radial dividing walls  10 A and  10 B and the recesses  32  and  36  of the injection valve  3 . The fresh gases G 1  drive out the remaining burnt gases G 2  from the previous combustion cycle. The remaining burnt gases G 2  are thus discharged from the combustion chamber  4  from apertures A 2  for accessing the nozzle  6 , which remain formed between the ends of the radial dividing walls  10 C and  10 D and the cut facets  52  and  56  of the ejection valve  5 . The radial heights of the access apertures A 1  and A 2  vary during the admission of the fresh gases G 1  and the discharging of the burnt gases G 2  between wide open and fully closed during the admission ( FIG. 6   a ) and discharge ( FIGS. 6   a  and  6   d ) phases. 
         [0064]    The rotating of the valves  3  and  5  will then isolate the combustion chamber  4  from the air sleeve  2  and the nozzle  6  ( FIG. 6   b ). For that, two circular faces of these valves  31 ,  35  and  51 ,  55 , respectively, are then in contact with the ends of the radial protrusions  10 A,  10 B in the case of the injection valve  3 , and  10 C,  10 D in the case of the ejection valve  5 . At the same time, the body  70  of the injector  7  driven in synchronous rotation closes off the ducts  71   c  and  71   d : the injection of fuel is cut off. The access apertures A 1  and A 2  are closed. 
         [0065]    Some of the burnt gases G 2  which are hot and at a raised pressure, stored in the ignition tank  8  during the previous combustion cycle, then leave the tank  8  via the ducts  8   c  and  8   d  in order to ignite the fresh gases G 1 : upon contact with these hot gases G 2 , the fresh gases G 1  ignite and combustion in the body of the combustion chamber  4  begins. 
         [0066]    During the combustion phase proper, the valves  3  and  5 —still rotating synchronously—continue to isolate the combustion chamber  4  so that combustion takes place at constant volume (the access apertures A 1  and A 2  remain closed). At the end of combustion ( FIG. 6   c ), some of the burnt gases G 2  fill the ignition tank  8  because of the reduced pressure prevailing in that tank by comparison with the pressure of the rest of the combustion chamber  4 . 
         [0067]    With reference to  FIG. 6   d , the faces  51  and  55  of the ejection valve  5  are some distance from the end of the respective walls  10 C and  10 D and the apertures A 2  providing access from the combustion chamber  4  to the nozzle  6  are open. The ejection valve  5  thus allows the burnt gases G 2  to be discharged toward the nozzle  6 . The injection valve  3  just begins to open the access apertures A 1  between the sleeve  2  and the combustion chamber  4 . New fresh gases G 1 , after an air/fuel premixture has been formed, will then be injected when the injection body  70  and the injection valve  3  have continued to turn according to the process explained hereinabove with reference to  FIG. 6   a . 
         [0068]    The combustion cycle in  FIGS. 6   a  to  6   d  repeats three times per complete rotation cycle of each cut facet  32 ,  34  and  36  of the injection valve  3  or  52 ,  54  and  56  of the ejection valve  5 , or alternatively per rotation cycle of the fuel injection body  70 . Throughout the duration that the access apertures A 1  are formed in each combustion cycle, the same quantity of premixture of fresh gases G 1  is introduced into the combustion chamber  4 , this quantity being predetermined according to the geometry and rotational speed of the valves so that the combustion chamber is filled under pressure conditions suited to ensuring full combustion of the gases. 
         [0069]    The invention is not restricted to the embodiments described and illustrated. It is, for example, possible to conceive of incorporating the thermal igniter into the combustion chambers of any type of heat engine. In addition, the fuel injector may also be designed to feed any type of heat engine. Furthermore, the design whereby the various compartments of the casing are separated is not limited to radial protrusions: this separation may be achieved by protrusions formed on the valves or by the valves themselves. Furthermore, the cut facets of the valves may be variable in width and the recesses formed may have any type of profile fit for the function. 
         [0070]    It is also possible to install the thermal ignition tank outside of the combustion chamber, for example by providing a tank—chamber connecting pipe. Moreover, it is possible to fit more than one ejection valve, for example two ejection valves with parallel axes in one and the same plane perpendicular to the median plane, operating in contrarotation.