Compressed-air engine comprising an integrated active chamber and with active distribution and comprising a balanced exhaust valve for cylinder deactivation

Abstract

The invention relates to an engine comprising an active chamber (CA), the engine comprising: a cylinder (1) supplied with compressed air; a piston (2); a cylinder head (6) that comprises an exhaust pipe (8); an exhaust opening (7); and an exhaust valve (9), wherein the volume of the cylinder (1) is divided into an integrated active chamber (CA) and an expansion chamber (CD), and the torque and the speed of the engine are controlled by the opening and the closing of the exhaust valve (9), characterised in that, in its opening direction, the exhaust valve (9) moves in the opposite direction to that of the flow of the pressurised gas stream and, in its closed position, it is held closed on a seat (20) by a return spring (13), and in that the axial forces exerted on the exhaust valve (9) which result from the pressure prevailing in the exhaust pipe (8) and in the cylinder (1) are permanently balanced.

Description

[0001] DESCRIPTION

[0002] TITLE: Compressed air engine with active chamber enclosed and active valve timing with balanced exhaust valve allowing cylinder deactivation

[0003] Technical field of the invention

[0004] The invention relates to an engine operating in particular with compressed air, or any other gas, and using a chamber called an “active chamber”.

[0005] The invention relates to the exhaust distribution of such an engine and more particularly for an engine comprising an included active chamber, and in particular for a multi-mode self-expanding engine with an included active chamber.

[0006] Technical background

[0007] Distribution refers to all the means used to supply such an engine with compressed gas.

[0008] The inventors and / or the applicant have filed numerous patents relating to motors and their installations, using gases and more particularly compressed air for completely clean operation in urban and suburban sites.

[0009] In particular, they filed an international patent application WO- A1-03 / 036088, the content of which can be referred to, concerning a motor-compressor - motor-alternator group with additional compressed air injection capable of operating in so-called single-energy mode and in so-called multi-energy mode.

[0010] In these types of engine operating with compressed air and comprising a compressed air storage tank, it is necessary to expand the compressed air stored at very high pressure in the tank - but whose pressure decreases as the tank empties - to a stable intermediate pressure called the final operating pressure, in a buffer capacity - called the working capacity - before its use in the engine cylinder(s).

[0011] To solve the problems of the regulator, the inventors and / or the applicant have also filed a patent application WO-A1 -03 / 089764, to the content of which reference may be made, concerning a dynamic regulator with variable flow and a distribution for engines supplied with compressed air injection, comprising a high-pressure compressed air reservoir and a working capacity.

[0012] In the operation of these "load expansion" engines, the filling of the expansion chamber always represents an expansion without work which is detrimental to the overall efficiency of the machine.

[0013] To solve the problem indicated above, the inventors and / or the applicant then filed a patent application WO-A1 -2005 / 049968 describing a compressed air engine powered preferentially by compressed air, or by any other compressed gas, contained in a high-pressure storage tank, previously expanded to a nominal working pressure in a buffer capacity called the working capacity.

[0014] In this type of engine according to the teachings of document W0-A1 -2005 / 049968:

[0015] - the expansion chamber consists of a variable volume equipped with means for producing work, it is twinned and in contact by a permanent passage with the space above the main engine piston which is equipped with a device for stopping the piston at its top dead center;

[0016] - during the stopping of the stroke of the engine piston at its top dead center, the air or gas under pressure is admitted into the expansion chamber when it is at its smallest volume and, under the thrust, will increase its volume by producing work;

[0017] - the expansion chamber being maintained substantially at its maximum volume, the compressed air contained therein then expands in the engine cylinder, thus pushing the engine piston back in its downward stroke, in turn providing work; - during the rise of the engine piston during the exhaust stroke, the variable volume of the expansion chamber is returned to its smallest volume to start a complete work cycle again.

[0018] The expansion chamber of the engine according to this invention actively participates in the work. The engine is therefore called an "active chamber" engine.

[0019] Document W0-A1 -2005 / 049968 teaches in particular a four-phase thermodynamic cycle during its operation in single-energy mode with compressed air characterized by:

[0020] - isothermal relaxation without work;

[0021] - a transfer - slight relaxation with so-called quasi-isothermal work;

[0022] - polytropic relaxation with work;

[0023] - an ambient pressure exhaust.

[0024] Document W0-A1 -2008 / 028881, which presents a variant of the teachings of document W0-A1 -2005 / 049968, teaches the same thermodynamic cycle, but using a known and conventional motion transformation device of the connecting rod-crank type, the expansion chamber of the engine according to the invention actively participating in the work. Engines according to the teachings of documents W0-A1 -2005 / 049968 and W0-A1 -2008 / 028881 are called "active chamber engines".

[0025] Subsequently, the inventors and / or the applicant filed a patent application for an air or compressed gas engine with an included active chamber which implements the same thermodynamic cycle as the engines according to the teachings of WO-A1-2005 / 049968 and WO-A1-2008 / 028881, as well as a conventional connecting rod-crank device.

[0026] According to the teachings of document W0-A1 -2012 / 045693, the inventors have proposed an engine with an included active chamber, comprising at least one piston mounted sliding in a cylinder and driving a crankshaft by means of a traditional connecting rod-crank device and operating according to a four-phase thermodynamic cycle comprising:

[0027] - isothermal relaxation without work;

[0028] - a transfer - slight relaxation with so-called quasi-isothermal work;

[0029] - polytropic relaxation with work;

[0030] - an ambient pressure exhaust.

[0031] Preferably supplied by compressed air, or any other compressed gas, contained in a high-pressure storage tank, through a buffer capacity called working capacity which is supplied by compressed air, or any other compressed gas, contained in a high-pressure storage tank, which is expanded to an average pressure called working pressure in a working capacity preferably through a dynamic expansion device, in which:

[0032] - the active chamber is included / incorporated into the engine cylinder;

[0033] - the engine cylinder comprises at least one piston mounted to slide in at least one cylinder, the volume swept by the piston of which is divided into two separate parts, a first part constituting the active chamber CA and a second part constituting the expansion chamber CD;

[0034] - the cylinder is closed at its upper part by a cylinder head comprising at least one duct and one intake orifice, and at least one duct and one exhaust orifice and which is arranged in such a way that, when the piston is at its top dead center, the residual volume between the piston and the cylinder head is, by construction, if not non-existent, reduced to only the minimum clearances allowing operation without contact between the piston and the cylinder head;

[0035] - compressed air or pressurized gas is admitted into the cylinder above the piston when the volume of the active chamber CA is at its smallest volume and which, under the continuous thrust of the compressed air at constant working pressure, will increase its volume by producing work representing the quasi-isothermal transfer phase;

[0036] - the admission of compressed air, or pressurized gas, into the cylinder is closed as soon as the maximum volume of the active chamber CA is reached, and the quantity of compressed air, or pressurized gas, included in said active chamber then expands by pushing the piston back on the second part of its stroke which determines the expansion chamber CD by producing work thus ensuring the expansion phase;

[0037] - the piston having reached its bottom dead center, the exhaust port is then opened to ensure the exhaust phase during the rise of the piston over its entire stroke.

[0038] The volume of the included active chamber CA and the volume of the expansion chamber CD are dimensioned in such a way that at the nominal operating pressure of the engine, the pressure at the end of expansion at bottom dead center is close to ambient pressure, in particular atmospheric. The volume of the active chamber is determined by the closure of the intake. Advantageously, and in particular in single-energy operation with compressed air, the engine with included active chamber described above comprises several successive cylinders of increasing displacements.

[0039] Preferably, the engine is powered, as taught in documents W0-A1-2005 / 049968 and W0-A1-2008 / 028881, by compressed air, or by any other compressed gas, contained in a high-pressure storage tank, previously expanded, to a nominal working pressure, in a buffer capacity - called working capacity.

[0040] However, even if it is possible in the case of a multi-stage engine to supply the first of the cylinders at high pressures, it remains necessary to expand the very high pressure compressed air contained in the high pressure storage tank to a nominal working pressure and this expansion operation either results in a loss of efficiency through the use of a conventional pressure reducer or, with the use of the teachings of WO-A1-03 / 089764, does not cost energy, but this expansion does not allow any expansion work to be carried out between the high pressure contained in the tank and the nominal working pressure in the constant volume working capacity.

[0041] The inventors and / or the applicant then filed a new patent application WO-A1-2012 / 045694 to the content of which reference may be made which claims a compressed air engine with an active chamber included in which:

[0042] - the high-pressure compressed air storage tank, or any other pressurized gas, directly supplies the engine cylinder intake;

[0043] - the filling of the active chamber included CA is carried out at a constant intake pressure at each engine revolution, this intake pressure decreasing as the pressure in the storage tank decreases as this tank is gradually emptied;

[0044] - the volume of the active chamber included CA is variable and is gradually increased as the pressure in the storage tank decreases, which determines said inlet pressure;

[0045] - the means for opening and closing the admission of compressed air into the included active chamber CA not only allow the orifice and the admission duct to be opened substantially at the top dead center of the piston stroke, but they also allow the duration and / or the angular sector of the admission to be modified, as well as the passage section of the opening;

[0046] - the volume of the included active chamber CA is sized for the maximum storage pressure, then it is gradually increased so that, depending on the intake pressure, the volume ratio between the included active chamber CA and the expansion chamber CD, the pressure at the end of expansion before the exhaust opens is close to atmospheric pressure.

[0047] The motor according to WO-A1-2012 / 045694 also acts as an expander, the invention thus making it possible to propose a so-called "self-expanding" motor which, for supplying the active AC chamber, does not require any independent expander of any type.

[0048] The multi-mode self-expanding engine with active chamber included according to the teachings of document WO-A1-2012 / 045694 notably implements, during its operation in compressed air single energy mode, a three-phase thermodynamic cycle comprising:

[0049] - an isobaric and isothermal transfer phase

[0050] - a polytropic relaxation phase with work

[0051] - an exhaust phase at ambient pressure.

[0052] In the operation of this engine, the volume, variable depending on the pressure of the high-pressure storage tank, of the included active chamber determines the quantity of compressed air injected. The higher the intake pressure, the smaller the volume of the active chamber must be. In order to obtain correct operation in all phases of use of the engine, it is therefore necessary to supply it with great precision according to the various parameters, in particular speed or rotational speed, supply pressure, load determined by the position of the accelerator, temperature.

[0053] For this purpose, it is necessary to be able to vary:

[0054] - the time of opening of the intake depending on the engine speed before or after top dead center to take into account the inertia of the gases, but also the ratio between the pressure establishment times,

[0055] - the moment of closing of the intake, depending on the engine speed, but also on the intake pressure,

[0056] - the lifting of the intake valve depending on the desired load. The difficulty lies in the realization of the means for opening and closing the intake of compressed air into the included active chamber which not only allow the opening and the intake duct to be opened substantially at the top dead center of the piston stroke, but which also allow the duration and / or the angular sector of the intake to be modified, as well as the passage section of the opening.

[0057] The distribution of engines of all types is generally ensured by valves whose operation is well known.

[0058] Thus, a valve closes the intake and / or exhaust duct and it comprises a valve head held by one or more springs bearing on a circular valve seat formed around an orifice connecting the intake and / or exhaust duct with the combustion and / or expansion chamber contained in the cylinder.

[0059] The valve head opens the circuit by entering the chamber to be supplied, driven by mechanical cam and pusher systems acting on the valve stem or rod which extends the valve head.

[0060] In other areas of motorization and for other technical reasons, particularly concerning the reduction of pollution and with the aim of controlling the intake and exhaust of conventional combustion engines, a large number of engine manufacturers are working on systems for controlling the phasing and duration of the opening of intake and exhaust valves during operation and have filed numerous patents concerning these applications. Complex mechanical systems controlled by stepper electric motors have also been developed and marketed, notably by BMW (Registered Trademark) with the device called "Vamos".

[0061] The inventors and / or the applicant have also filed patent application WO-A1-03 / 089764, the contents of which may be referred to concerning a distribution by progressively controlled valve. Much work has been undertaken concerning electromechanical devices, in particular those controlled by electromagnets that are easily controlled to take into account the various operating parameters, but the electrical powers that must be implemented to enable the accelerations and the speed of movement of the valves require, given the weight and inertia of the latter, considerable powers.

[0062] To solve the problems mentioned above while providing increased power, the inventors and / or the applicant filed patent application W0-A2-2015 / 177076 relating to a compressed air engine with an included active chamber and active intake distribution.

[0063] The active intake distribution device according to this document applied to compressed air engines uses the compressed air contained in the high pressure storage tank and / or in the intake circuit to move the intake valve in order to open and then close the intake duct to supply the active chamber of the engine, the compressed air used for these actions then being reused in the engine to produce additional work.

[0064] An active chamber engine operating according to a three-phase thermodynamic cycle was thus proposed, comprising:

[0065] - an isobaric and isothermal transfer phase;

[0066] - a polytropic relaxation phase with work;

[0067] - an exhaust phase at ambient pressure; this engine comprising:

[0068] - at least one cylinder supplied by a pressurized gas, preferably by compressed air, contained in a high-pressure storage tank,

[0069] - at least one piston which is slidably mounted in this cylinder,

[0070] - a crankshaft driven by the piston by means of a traditional connecting rod-crank device,

[0071] - a cylinder head which closes at its upper part the volume of the cylinder, which is swept by the piston, and which comprises at least one intake duct in which flows a flow of pressurized gas for filling the cylinder, an intake orifice for the pressurized gas above the piston, and at least one exhaust orifice and one exhaust duct, the cylinder head being arranged in such a way that, when the piston is at its top dead center, the residual volume between the piston and the cylinder head is, by construction, reduced to only the minimum clearances allowing operation without contact between the piston and the cylinder head,

[0072] - at least one intake valve which cooperates in a sealed manner with a valve seat formed in the cylinder head and which delimits the intake orifice, engine in which:

[0073] -- the volume of the cylinder swept by the piston is divided into two distinct parts, a first part constituting an active chamber which is included in the cylinder and a second part constituting an expansion chamber,

[0074] -- under the continuous thrust of the pressurized gas admitted into the cylinder, at constant working pressure, the volume of the active chamber increases, producing work representing the isobaric and isothermal transfer phase, -- the admission of the pressurized gas into the cylinder is closed as soon as the maximum volume of the active chamber is reached, the quantity of pressurized gas included in said active chamber then expanding, pushing the piston back on the second part of its stroke which determines the expansion chamber, producing work thus ensuring the polytropic expansion phase,

[0075] -- the piston having reached its bottom dead center, the exhaust port is then opened to ensure the exhaust phase during the rise of the piston over its entire stroke to its top dead center,

[0076] -- the torque and the engine speed are controlled by the opening and closing of the intake valve by allowing the intake valve to be opened, substantially at the top dead center of the piston stroke, and by allowing, by closing the valve, to modify the duration and / or the angular sector of the intake, as well as the passage section of the intake opening in order, depending on the pressure of the compressed gas contained in the storage tank and the pressure at the end of the expansion phase, to determine the quantity of pressurized gas admitted as well as the volume of the active chamber, in which:

[0077] - a) the inlet valve is mounted to move axially between a low closed position in which it is in sealed contact with its valve seat, and a high open position,

[0078] - b) in the direction of its opening, the inlet valve moves axially, in the direction opposite to that of the flow of the pressurized gas filling the cylinder,

[0079] - (c) in its closed position, the inlet valve is held autoclavably closed on its valve seat by the pressure prevailing in the inlet duct and applied to the inlet valve,

[0080] - d) the engine includes means for controlling the opening of the intake valve, substantially at the top dead center of the piston stroke, to cause the intake valve to detach from its seat to allow the intake pressure to be established in the active chamber, the valve then traveling its complete opening stroke under the action of the differential pressure forces exerted by the pressurized gas on the corresponding parts of the intake valve,

[0081] - e) the engine comprises a pneumatic cylinder for closing the inlet valve which comprises a cylinder cylinder and a closing piston which is linked in axial displacement with the inlet valve, and which is slidably mounted in the cylinder cylinder inside which it delimits in a sealed manner a control chamber of the cylinder, called closing chamber,

[0082] - f) the engine comprises at least one intake valve opening control channel which connects said closing chamber to a source of pressurized gas which is either the upper part of the active chamber of the cylinder, or the intake duct, or the pressurized gas reservoir,

[0083] - g) the engine comprises an active distribution channel which connects said closing chamber to the upper part of the active chamber and a valve for shutting off the circulation of gas in the active distribution channel, called the active distribution valve, the opening of which is controlled to put the closing chamber in communication with the upper part of the active chamber, close the intake valve and produce work which is added to the work of the charge of pressurized gas previously admitted, via the intake duct, into the active chamber.

[0084] You can refer to the contents of this document for details of other engine characteristics.

[0085] The invention aims to propose a new design of such an active chamber compressed air engine aimed in particular at increasing its performance and efficiency, in particular by using a distribution system for controlling the opening and closing of the exhaust valve using a source of compressed gas - in particular compressed air - whose pressure value (called low pressure) is lower than that of the pressure available in the high-pressure storage tank.

[0086] The "pneumatic" energy required to open and close the exhaust valve is, for example, supplied in the form of gas from the high-pressure storage tank or the intake circuit, which is expanded to low pressure. After being used to control the opening of the exhaust valve, this energy can then be reused to produce additional work.

[0087] The volumes of the closing and / or opening chambers are of reduced value, for example, but not limited to less than 10% of the engine displacement. The same applies to the conduits connecting the intake and the active chamber, the intake and the closing chamber, the closing chamber and the expansion chamber are calculated to allow sufficient flow to establish pressures in the various active driving chambers, closing distributor, expansion distributor.

[0088] Summary of the invention

[0089] The invention proposes an active chamber engine operating according to a three-phase thermodynamic cycle comprising:

[0090] - an isobaric and isothermal transfer phase;

[0091] - a polytropic relaxation phase with work;

[0092] - an exhaust phase at ambient pressure; this engine comprising;

[0093] - at least one cylinder supplied by a pressurized gas, preferably by compressed air, contained in a high-pressure storage tank,

[0094] - at least one piston which is slidably mounted in this cylinder,

[0095] - a crankshaft driven by the piston by means of a traditional connecting rod-crank device

[0096] - a cylinder head which closes at its upper part the volume of the cylinder which is swept by the piston, and which comprises at least one intake duct in which flows a flow of gas under pressure for filling the cylinder, an intake orifice for the gas under pressure above the piston, and at least one exhaust orifice and an exhaust duct which is connected to the atmosphere in which flows a flow of gas under pressure for emptying the cylinder, the cylinder head being arranged in such a way that, when the piston is at its top dead center, the residual volume between the piston and the cylinder head is, by construction, reduced to only the minimum clearances allowing operation without contact between the piston and the cylinder head,

[0097] - at least one intake valve which cooperates in a sealed manner with an intake valve seat formed in the cylinder head and which delimits the intake orifice,

[0098] - at least one exhaust valve which cooperates in a sealed manner with an exhaust valve seat formed in the cylinder head and which delimits the exhaust orifice, engine in which:

[0099] -- the volume of the cylinder swept by the piston is divided into two distinct parts, a first part constituting an active chamber which is included in the cylinder and a second part constituting an expansion chamber, -- under the continuous thrust of the pressurized gas admitted into the cylinder, at constant working pressure, the volume of the active chamber increases, producing work corresponding to the isobaric and isothermal transfer phase of the thermodynamic operating cycle,

[0100] -- the admission of pressurized gas into the cylinder is closed as soon as the maximum volume of the active chamber is reached, the quantity of pressurized gas contained in said active chamber then expanding by pushing the piston back on the second part of its stroke which determines the expansion chamber by producing work corresponding to the polytropic expansion phase of the thermodynamic operating cycle,

[0101] -- the piston having reached its bottom dead center, the exhaust port is then opened to carry out the exhaust phase of the thermodynamic operating cycle during the rise of the piston over its entire stroke to its top dead center,

[0102] -- the torque and the engine speed are controlled by the opening and closing of the intake valve by allowing the intake valve to be opened, substantially at the top dead center of the piston stroke, and by allowing, by closing the valve, to modify the duration and / or the angular sector of the intake, as well as the passage section of the intake opening in order, as a function of the pressure of the compressed gas contained in the storage tank and the pressure at the end of the expansion phase, to determine the quantity of pressurized gas admitted as well as the volume of the active chamber, characterized in that:

[0103] - a) the exhaust valve is mounted so as to be able to move axially between a low closed position in which it is in sealed contact with its exhaust valve seat, and a high open position,

[0104] - b) in the direction of its opening, the exhaust valve moves axially, in the direction corresponding to that of the flow of the pressurized gas stream out of the cylinder,

[0105] -c) in its closed position, the intake valve is held closed on its exhaust valve seat by a spring,

[0106] - d) the axial forces exerted on the exhaust valve which result from the pressure prevailing in the exhaust duct and in the cylinder are permanently balanced,

[0107] - e) the engine includes a pneumatic cylinder for controlling the opening of the exhaust valve, substantially at the bottom dead center of the piston stroke, to cause the exhaust valve to detach from its seat to carry out the exhaust phase of the thermodynamic operating cycle during the rise of the piston over its entire stroke to its top dead center, the valve then traveling its complete opening stroke against the force exerted by the return spring,

[0108] - f) the pneumatic cylinder comprises a cylinder and a piston which is connected to the exhaust valve and which delimits a pilot chamber which is connected to a low pressure gas source,

[0109] - g) the engine has a channel which connects the source of low-pressure gas to the pilot chamber, and a valve a controlled valve for admitting the low-pressure gas into the pilot chamber,

[0110] - i) the engine comprises a control channel for closing the exhaust valve which connects the pilot chamber to the open air or to an energy recovery system, and a controlled valve for emptying the pilot chamber, and in that, to deactivate said at least one cylinder during one rotation of the crankshaft, from one passage of the piston to top dead center until the next passage of the piston to top dead center:

[0111] - the inlet valve is kept closed to block the admission of pressurized gas into the cylinder during said rotation;

[0112] - and, simultaneously during said rotation, the exhaust valve is kept open in a state known as cylinder deactivation.

[0113] According to other characteristics of the invention:

[0114] - during the first half of said at least one revolution, air at atmospheric pressure is drawn through the exhaust duct which, during the second half of said at least one revolution, is then drained out of the cylinder through the exhaust duct;

[0115] - said at least one cylinder is deactivated during several successive rotations of the crankshaft;

[0116] - the engine comprises at least two cylinders, each piston of which drives the same crankshaft by means of a traditional connecting rod-crank device, and each cylinder of which is produced according to the invention and in which, during said at least one revolution of one of said at least two cylinders during which it is deactivated, another of said at least two cylinders is an active cylinder operating according to said three-phase thermodynamic cycle;

[0117] - the engine comprises at least three cylinders, each piston of which drives the same crankshaft by means of a traditional connecting rod-crank device, and each cylinder of which is made according to the invention, and, during said at least one revolution of one of said at least three cylinders during which it is deactivated, the at least two other cylinders are active cylinders operating according to said three-phase thermodynamic cycle;

[0118] - the engine an energy recovery system, a channel which connects the energy recovery system to the upper part of the cylinder located above the piston, and a valve an active drain valve of the energy recovery system in the upper part of the cylinder;

[0119] - the inlet, drain and active drain valves C) are controlled according to the following cycle:

[0120] - i) opening of the intake valve to put the pilot chamber in communication with the low pressure gas source and cause the exhaust valve to open around the bottom dead center of the piston to put the exhaust duct in communication with the volume of the cylinder swept by the piston,

[0121] - ii) closing the inlet valve and opening the drain valve when the piston reaches the top dead center of its stroke to cause a drop in pressure in the pilot chamber and to cause the exhaust valve to close

[0122] - iii) closing the valve and, when the pressure in the cylinder is less than or equal to the pressure in the energy recovery system, opening the active drain valve to introduce into the cylinder a charge which is added to the charge previously admitted into the active chamber,

[0123] - iv) closing of the active drain valve when the piston rises;

[0124] - the pneumatic cylinder controlling the opening of the exhaust valve is integrated into the cylinder head and its piston is integral with the exhaust valve rod;

[0125] - the pneumatic cylinder controlling the opening of the exhaust valve is arranged outside the cylinder head, and the output member of the cylinder is connected, directly or indirectly, to the rod of the exhaust valve by a movement transmission member;

[0126] - the pneumatic cylinder controlling the opening of the exhaust valve is a pneumatic muscle, and said movement transmission member is a rocker which is pivotally mounted around an axis which is orthogonal to the sliding axis of the exhaust valve, one of the ends of which is connected, directly or indirectly, to the rod of the exhaust valve, and the other opposite end is connected to the output member of the pneumatic control cylinder;

[0127] - the position of the rocker pivot axis is adjustable between its two opposite ends;

[0128] - the exhaust valve stem is axially crossed by a pressure balancing channel which opens into a compensation chamber and into the upper part of the cylinder;

[0129] - the low-pressure gas source is a regulator whose inlet is connected to the high-pressure storage tank or the inlet duct, and whose outlet is connected to the pilot chamber;

[0130] - the regulator is a variable outlet pressure regulator controlled to vary the value of the lift of the exhaust valve from its seat.

[0131] Brief description of the figures

[0132] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0133] [Fig.lA] - Figure 1A schematically represents a first embodiment of an engine according to the invention, with an active chamber included in the cylinder, which is illustrated in axial section at its bottom dead center, and its compressed air supply device;

[0134] [Fig.1 B] - Figure 1B is a view similar to that of Figure 1A in which the engine is illustrated, at its top dead center, the exhaust valve having been opened from bottom dead center;

[0135] [Fig.2] - Figure 2 is a view similar to that of Figure 1A which illustrates a second embodiment of an engine according to the invention;

[0136] [Fig.3] - the figure is a view similar to that of figure 1A which illustrates a third embodiment of an engine according to the invention;

[0137] [Fig.4] - Figure 4 is a view similar to that of Figure 3 which illustrates an alternative embodiment of the third embodiment;

[0138] [Fig.5] - Figure 4 is a view similar to that of Figure 3 which illustrates another variant embodiment of the third embodiment;

[0139] [Fig.6] - Figure 6 is an axial sectional view of an exemplary embodiment of a modular cartridge incorporating a valve capable of being integrated into an engine of the type illustrated schematically in Figures 3 and 4;

[0140] [Fig.7] - Figure 7 schematically represents the deactivation of a cylinder according to the invention;

[0141] [Fig.8] - Figure 8 schematically represents the deactivation according to the invention of one of the cylinders of a three-cylinder engine according to the invention.

[0142] Detailed description of the invention

[0143] The engine comprises one or more cylinders, of which only one 1 is shown which is supplied by a pressurized gas, preferably by compressed air, contained in a high-pressure storage tank 12. The engine comprises a piston 2 which is slidably mounted along its axis in the cylinder 1, and a crankshaft 5 which is driven by the piston 2 by means of a conventional device with connecting rod 3 and crank 4.

[0144] The engine has a cylinder head 6 which closes at its upper part the internal volume of cylinder 1 which is swept by piston 2.

[0145] The internal volume of cylinder 1 which is swept by piston 2 is divided along an imaginary line DD' (corresponding to a division plane orthogonal to the axis of cylinder 1) into two parts or chambers comprising:

[0146] - a first upper part constituting the active chamber CA, which is thus included in the cylinder 1;

[0147] - and a second lower part constituting the expansion chamber CD. The cylinder head 6 comprises at least one exhaust duct 8 which is connected to the atmosphere and in which the flow of exhaust gas from the cylinder 1 flows. The exhaust duct 8 terminates at its lower end in an exhaust orifice 7 arranged above the piston 2.

[0148] The cylinder head 6 and the piston 2 are arranged in such a way that, when the piston 2 is at its top dead center, the residual volume between the piston 2 and the cylinder head 6 is, by construction, reduced to only the minimum clearances allowing operation without contact between the piston 2 and the cylinder head 6, that is to say without contact between the upper face 30 of the piston 2 and the portion opposite the lower face 32 of the cylinder head 6 which closes the cylinder 1 at its upper part.

[0149] To open or close the exhaust orifice 7, the cylinder head 6 comprises an exhaust valve 9, which is in particular capable of cooperating in a sealed manner with an exhaust valve seat 20 formed in the cylinder head 6 and which delimits the exhaust orifice 7.

[0150] The cylinder head 6 also comprises at least one intake valve, at least one intake port and at least one exhaust duct (not shown) and whose design and operation are similar to the exhaust system described here in detail.

[0151] In such an engine in which the volume of cylinder 1 swept by piston 2 is divided into a chamber called active chamber CA which is included in cylinder 1, and a second part constituting an expansion chamber CD:

[0152] - a) under the continuous thrust of the pressurized gas admitted into cylinder 1, at constant working pressure, the volume of the active chamber CA increases, producing work corresponding to the first quasi-isothermal transfer phase of the thermodynamic operating cycle;

[0153] - b) the admission of pressurized gas into the cylinder 1 is closed as soon as a chosen maximum volume of the active chamber CA is reached, the quantity of pressurized gas included in the active chamber CA then expanding by pushing the piston 2 back on the second part of its downward stroke which determines the volume of the expansion chamber CD by producing work corresponding to the second expansion phase of the thermodynamic operating cycle;

[0154] - c) when the piston 2 has reached its bottom dead center (BDC), the exhaust port is opened by controlling the exhaust valve 9 to - during the rise of the piston 2 over its entire stroke to its top dead center (TDC) - carry out the third exhaust phase of the thermodynamic operating cycle.

[0155] The torque supplied by the engine is controlled by controlling the opening and closing of the intake valve by opening it at the top dead center TDC of the stroke of the piston 2 and closing it to modify the duration and / or the angular sector of the intake, as well as the passage section of the intake opening, in particular as a function of the value of the pressure of the gas contained in the storage tank 12. This determines the quantity of pressurized gas which is admitted into the cylinder, as well as the volume of the active chamber CA.

[0156] The intake duct (not shown) is directly connected to the high-pressure gas reservoir 12 which thus directly supplies the active chamber CA, the latter thus being at the same pressure as that of the gas contained in the reservoir 12, for example of the order of 100 bars and it is higher than that prevailing in the active chamber CA and the expansion chamber CD, for example equal to 1.5 bars at the moment of the cycle corresponding to the bottom dead center PMB of the piston, at the end of expansion, just before the opening of the exhaust valve.

[0157] The exhaust valve 9 is slidably guided in a valve guide 206 and is mounted to move axially - along its main axis - between:

[0158] - a low closing or blocking position (considering the general vertical orientation of the figures and without reference to Earth's gravity) which is shown in Figure 1A and in which the lower part or head 25 of the valve is in sealed contact with the exhaust valve seat 20; and

[0159] - a high opening position shown in figure 1B.

[0160] In the direction of its opening, the exhaust valve 9 moves axially - upwards, in the direction corresponding to that of the flow of the flow F of exhaust gas from the cylinder. Thus, the exhaust valve opens in the direction of the flow of exhaust air from the engine cylinder. The engine comprises a pneumatic cylinder, or gas cylinder, V for controlling the opening of the exhaust valve 9 which, by way of non-limiting example and according to the design illustrated in FIGS. 1A to 1 C, is arranged in the cylinder head 6.

[0161] The jack V comprises a jack cylinder and a closing piston P which is linked in axial displacement with the upper rod 26 of the exhaust valve 9, and which is slidably mounted in the cylinder of the jack V inside which it delimits in a sealed manner a lower chamber 100, called the opening chamber of the exhaust valve 9, or pilot chamber.

[0162] Above the piston P, the jack cylinder has an upper chamber 99 in which is housed an elastic return spring 13 of the exhaust valve 9 which is for example a helical spring which is mounted compressed in the upper chamber 99 and which exerts an elastic force oriented downwards on the upper face 27 of the piston P. Above the upper chamber 99 housing the return spring 13, the jack cylinder is extended by an upper section 98 of smaller diameter in which the upper part of the rod 26 of the exhaust valve 9 - which extends above the piston P - is received in axial sliding.

[0163] The upper free end face 22 of the rod 26 of the exhaust valve 9 delimits in the section 98 an upper chamber 101 called the compensation chamber.

[0164] The compensation chamber 101, also called the pressure balancing chamber, is permanently connected to the upper part of the cylinder 1 located above the piston 2 by a central channel 102 opening at its two opposite ends which extends axially through the exhaust valve 9 over its entire height.

[0165] A channel X1 connects the exhaust duct 8 to the lower compensation chamber 100 of the cylinder V.

[0166] The engine comprises a controlled valve A called the intake valve which is arranged in the channel X1, and the opening of which can be controlled to put the reservoir 12 in communication with the compensation chamber 100.

[0167] A pressure reducer 10 is interposed in the channel X1, here preferably upstream of the valve A, to reduce the pressure at the outlet of the pressure reducer 10 to a so-called low pressure value of the order of a few bars - for example equal to 8 bars - to supply the compensation chamber 100. The pressure reducer 10 may have a constant outlet pressure or, alternatively, an adjustable outlet pressure. When the outlet pressure of the pressure reducer is adjustable, controlling its value makes it possible to vary the value of the valve lift.

[0168] The lower compensation chamber 100 is here connected to the upper part of the cylinder 1 located above the piston 2 by two consecutive channels X2 and X3 with the interposition of an energy recovery system 11.

[0169] The engine comprises a controlled valve B called a drain valve B for shutting off arranged in the channel X2, the opening of which can be controlled to put the compensation chamber 100 in communication with the potential energy recovery system 11.

[0170] The engine has a controlled valve C, called an active drain valve, which connects the upper part of the cylinder 1 to the potential energy recovery system 11 and whose opening can be controlled to connect the potential energy recovery system 11 to the cylinder 1.

[0171] The exhaust valve 9 is permanently returned to its closed position. For example, the exhaust valve 9 is elastically returned and is held closed on its valve seat 20 by a return spring 13.

[0172] By virtue of its design according to the invention, the exhaust valve 9 is balanced against the pressure forces prevailing in the cylinder 1 which are applied to the lower face 21 of the head 25 of the valve.

[0173] This is achieved by the presence of the upper compensation chamber 101 which is connected to the upper part of the cylinder 1 by the channel 102.

[0174] We thus note that the value of the pressure prevailing in the compensation chamber 101 is always equal to the value of the pressure in the cylinder 1.

[0175] The surface area of ​​the upper free end face 22 of the stem 26 of the exhaust valve 9 which is equivalent to the surface area of ​​the lower face 21 of the head 25 of the exhaust valve 9 which is subjected to the same pressure value, thus making it possible to cancel out the effects on the valve resulting from the pressure.

[0176] The engine comprises a so-called low-pressure distribution system which is connected to the exhaust duct 8 by the pressure reducer 10, the outlet pressure value of which is lower than the pressure of the high-pressure gas contained in the tank 12.

[0177] The maximum value of the pressure prevailing in the distribution system, downstream of the pressure reducer 10, is constant throughout the progressive emptying of the reservoir 12. This maximum value of the pressure prevailing in the distribution system corresponds at least to obtaining a complete lift stroke of the intake valve, but it can vary below this maximum value in order to reduce the stroke of the intake valve.

[0178] When the piston 2 approaches the bottom dead center PMB of its stroke, the so-called intake valve A opens the channel X1 to pressurize the pilot chamber 100 by connecting it to the outlet of the regulator 10.

[0179] The pilot pressure is then applied to the lower surface 23 of the piston P secured to the rod or tail of the exhaust valve 9. The force thus applied to the exhaust valve 9 is greater than the downward return force exerted by the spring 13 on the upper face 27 of the piston P, and it causes the valve 9 to detach or lift from the seat 20.

[0180] The exhaust valve 9 then travels its entire opening stroke and puts the exhaust duct 8 in communication with the atmosphere.

[0181] Only the force exerted on the one hand by the spring 13 and, on the other hand, the pressure force exerted on the face 23 act on the exhaust valve 9. When the piston 2 reaches the top dead center TDC of its axial stroke, the intake valve A is closed and the drain valve B is opened to cause the gas to expand to a pressure value lower than the pilot pressure prevailing in the pilot chamber 100.

[0182] The drop in the value of the gas pressure applied to the lower face 23 of the piston P and the value of the return force exerted permanently by the return spring 13 then cause the exhaust valve 9 to descend until its head 25 is in sealed contact with the valve seat 20.

[0183] The command to open the drain valve B puts the pilot chamber 100 in communication with the potential energy recovery system 11.

[0184] With the exhaust valve 9 closed, the gas present in the cylinder 1 is compressed as the piston 2 rises and its value increases.

[0185] When the pressure value in cylinder 1 is less than or equal to the pressure value in the potential energy recovery system 11, the closing of the drain valve B is commanded, and the opening of the active drain valve C is commanded in turn to - via channel X3 - put the potential energy recovery system 11 in communication with cylinder 1. The design of the potential energy recovery system 11 can take several forms, depending on the type of energy that is to be recovered, and for example:

[0186] - the form of a potential energy recovery system whose purpose is to reinject into the cylinder 1 the pressurized gas used in the active distribution system in order to produce additional mechanical work by means of the piston 2 - according to the embodiment illustrated in the figures; or

[0187] - alternatively the form of a potential and kinetic energy recovery system through a turbine system (not shown); or

[0188] - alternatively the form of a thermal energy recovery system (not shown).

[0189] A combination of one or more of these energy recovery systems can be considered.

[0190] In the first case illustrated in the figures, the volume of gas recovered and accumulated in a capacity 11 is injected into the cylinder 1 by expanding in the expansion chamber CD of the engine, producing work which is added to the expansion work of the charge admitted into the active chamber CA. Thus, within the meaning of the invention, the valve C is an active distribution valve.

[0191] We can therefore understand the operation of the so-called active distribution according to the invention in which, advantageously, the energy necessary for controlling the opening and closing of the exhaust valve 9 is reused in whole or in part, in different possible forms.

[0192] The inlet valve and inlet duct are not shown in Figures 1A to 6, but the assembly is of the same design and operates on the same principle as that which governs the exhaust.

[0193] The exhaust valve control system may be connected to the same pressure reducer 10 or potential energy recovery system 11 as those belonging to the exhaust valve control system 9. The exhaust valve opening cycle is close to an opening at the bottom dead center of the piston stroke 2 and close to a closing at the top dead center of the piston stroke 2.

[0194] Description of the second embodiment

[0195] The following description is made by comparison with the first embodiment previously described with reference to Figures 1A and 1B.

[0196] In the design according to this second embodiment illustrated in Figure 2, the two valves A and B illustrated in Figures 1A and 1B are replaced by a slide valve E commonly called a distributor.

[0197] The distributor E is of the two-position, three-way type. In its state or position illustrated in the figure, the pilot chamber 100 is connected to the channel X2 upstream of the potential energy recovery system 11.

[0198] A change in position of the distributor slide causes the outlet of the regulator 10 to be put into communication with the control chamber 100 and the interruption of communication between the control chamber 100 and the channel X2.

[0199] The design of the exhaust valve which has just been described and its control and piloting means apply in an identical manner to the intake valve (Cf. FR3097254B3).

[0200] Description of the third embodiment

[0201] The following description is made by comparison with the first embodiment previously described with reference to Figures 1A and 1B.

[0202] In the design according to this third embodiment illustrated in Figure 3, the possibility of offsetting the pilot chamber relative to the valve 9 is highlighted by means of a rocker 14 mechanically connecting the exhaust valve 9 to a pneumatic cylinder V comprising the pilot chamber 100.

[0203] The cylinder V is offset or laterally displaced and it can in particular be arranged outside the cylinder head 6 in the form of an independent discrete component.

[0204] This design makes it easier to size the V cylinder and the pilot chamber.

[0205] It also facilitates manufacturing and maintenance, and it makes it possible to limit the disadvantages due to leaks which may be present at the level of the piston P of the cylinder V illustrated according to the first embodiment.

[0206] As a non-limiting example, a V cylinder for controlling the opening of the valve may be of the so-called "pneumatic muscle" type, the force / stroke behavior of which is quasi-linear and the stroke of which is directly adjustable by adjusting the value of its supply pressure. Such a cylinder may be used with a low supply pressure equal to or less than, for example, 8 bars.

[0207] This type of pneumatic muscle (Fluidic Muscle DMSP) is for example marketed under the registered trademark “FESTO”.

[0208] The rocker 14 is pivotally mounted around an axis 15 which is orthogonal to the sliding axis of the exhaust valve 9. One of its ends is connected directly or indirectly to the rod 26 of the valve, and its other opposite end is connected to the output member 17 of the offset cylinder V. According to a first variant and as illustrated in Figure 4, the two valves A and B of Figure 3 can be replaced by a slide valve or distributor E.

[0209] According to another variant and as illustrated in Figure 5, and by comparison with the embodiment previously described with reference to Figure 3, the possibility of adjusting the position of the pivot axis 15 of the rocker 14 and thus of varying the stroke of the valve 9 as a function of the different operating phases of the engine has been shown.

[0210] Description of a cartridge incorporating a valve

[0211] Figure 6 shows a cartridge 200 comprising a housing in two parts, lower 202 and upper 204, which house an external valve guide 206 which slidably guides the stem 26 of a valve 9, the lower head 25 of which is illustrated opposite a valve seat 20 integrated into the lower part 202 of the housing of the cartridge 200.

[0212] The inlet orifice 7 is formed in the lower part 202 of the cartridge housing and is here cylindrical with a circular section.

[0213] The upper section of the rod 25 is shaped into a hollow piston P in which an internal valve guide 207 is received in a sealed manner.

[0214] Within the meaning of the invention, the compensation chamber 101 is thus arranged at the interface between the upper face 22 of the rod 25 - into which the balancing channel 102 opens - and the lower face portion opposite 209 of the internal guide 207.

[0215] The external guide 206 and the lower part 202 of the housing are crossed by vent passages 210.

[0216] In Figure 6, the valve 9 is illustrated in its maximum high position corresponding to the command for its complete opening.

[0217] This position is determined by a mechanical stop surface 212 carried by the upper part 204 of the housing against which the upper face 27 bears axially upwards.

[0218] The hollow piston P secured to the rod 25 is capable of being driven in axial sliding in both directions - between its high position illustrated in figure 6 and its low position in which the head 25 is in axial downward support against the seat 20 (See figure 7) - by a rocker 14 which is pivotally mounted around a fixed axis 15 carried by the upper part 204 of the cartridge housing 200.

[0219] The free end 214 of the rocker 14 is capable of being connected in an articulated manner to the output rod of an actuator or control cylinder which is for example a pneumatic muscle as illustrated in FIG. 7.

[0220] Description of the operation according to the invention in deactivation mode of one or more cylinders In accordance with the invention, the design of the valve control, and in particular of the exhaust valve, makes it possible to deactivate - or "neutralize" the cylinder during a complete rotation of the crankshaft (i.e., 360 degrees of rotation angle) from a first passage of the piston to its top dead center TDC to a second following passage of the piston to its top dead center TDC.

[0221] This deactivation is achieved by keeping the intake valve closed for the entirety of this "deactivated" revolution and keeping the exhaust valve open also for the entirety of this same "deactivated" revolution.

[0222] Thus, the intake valve is kept closed to block the admission of pressurized gas into the cylinder (1) during this rotational revolution and, simultaneously during this same rotational revolution, the exhaust valve is kept open in a state known as cylinder deactivation.

[0223] This deactivation principle is shown diagrammatically in Figure 7 where, with the intake valve A1 closed, the pressurized air from the reservoir 12 is not admitted into the cylinder.

[0224] During the descent of the piston from its top dead center TDC to its bottom dead center PMD (corresponding to the first half of the considered rotation of the crankshaft from 0 to 180 degrees of angle), the exhaust valve E1 being kept open, the air at atmospheric ambient pressure is sucked through the exhaust duct.

[0225] When the piston rises from its bottom dead center (BDC) to its top dead center (TDC) (corresponding to the second half of the considered rotation of the crankshaft from 180 to 360°), the air at ambient pressure present in the cylinder is forced to the exhaust through the exhaust duct. Thus, the operation of this cylinder is then "neutral" or

[0226] “transparent”, the pressure acting on the piston being the ambient pressure during the entire rotation of the crankshaft during the revolution considered.

[0227] As shown schematically in Figure 8, the principle of implementing the deactivation of a cylinder according to the invention can be implemented in the context of an engine with at least two cylinders whose pistons drive the same crankshaft.

[0228] This operation allows only certain cylinders to be used (as desired) and others to be made "neutral" or "transparent". This allows the overall engine load to be adjusted while still having full load operation (i.e. at best efficiency) on one or more non-deactivated cylinders. For example, on a three-cylinder engine, single-cylinder operation corresponds to one-third of the maximum load, with only one "active" cylinder operating at full load.

[0229] Figure 8 illustrates an example of an engine according to the invention with three identical in-line cylinders.

[0230] Each inlet valve, respectively A1, A2 and A3, is connected to the same pressurized air tank 12.

[0231] As shown in Figure 8, the first cylinder (Right) is an active cylinder, while the second and third cylinders are each in a "deactivated" operating state according to the principle described above with reference to Figure 7.

[0232] In the same way it is possible to deactivate the first cylinder and the third cylinder, or even the first cylinder and the second cylinder.

[0233] Deactivation of a cylinder can be done by a number of consecutive crankshaft revolutions, for example for 1000 revolutions, then changing the "deactivated" cylinder.

[0234] This type of deactivation "cycle" advantageously allows for regular wear of all the engine cylinders.

[0235] It is also possible to deactivate only one of the three cylinders while keeping the other two "active", that is to say in a mode allowing operation at two-thirds of the engine load.

[0236] In such a case, the deactivation of each of the three cylinders can of course be varied cyclically.

[0237] To obtain "intermediate" engine loads (i.e. here different from 1 / 3, 2 / 3 or 3 / 3) it is the active mode management of the active chambers of each cylinder - or of all three active cylinders - which allows the output torque value to be controlled.

Claims

DEMANDS 1. Active chamber engine operating according to a three-phase thermodynamic cycle comprising: - an isobaric and isothermal transfer phase; - a polytropic relaxation phase with work; - an ambient pressure exhaust phase; this engine comprising: - at least one cylinder (1) supplied by a pressurized gas, preferably by compressed air, contained in a high-pressure storage tank (12), - at least one piston (2) which is mounted to slide within this cylinder (1), - a crankshaft (5) driven by the piston by means of a traditional connecting rod-crank mechanism (3,4), - a cylinder head (6) which closes at its upper part the volume of the cylinder (1) which is swept by the piston (2), and which includes at least one intake port into which flows a flow of pressurized gas for filling the cylinder, an intake orifice (7) for the pressurized gas above the piston, and at least one exhaust orifice and an exhaust duct (8) which is connected to the atmosphere into which flows a flow of pressurized gas for emptying the cylinder (1), the cylinder head being arranged such that, when the piston (2) is at its top dead center, the residual volume between the piston (2) and the cylinder head (6) is, by construction, reduced to only the minimum clearances allowing operation without contact between the piston (2) and the cylinder head (6), - at least one intake valve which cooperates in a sealed manner with an intake valve seat formed in the cylinder head (6) and which delimits the intake port, - at least one exhaust valve (9) which cooperates in a sealed manner with an exhaust valve seat (20) formed in the cylinder head (6) and which delimits the exhaust port (7), engine in which: -- the volume of the cylinder (1) swept by the piston (2) is divided into two distinct parts, the first part constituting an active chamber (CA) which is included in the cylinder (1) and the second part constituting an expansion chamber (CD), -- under the continuous pressure of the gas admitted into cylinder (1), at constant working pressure, the volume of the active chamber (CA) increases, producing work corresponding to the isobaric and isothermal transfer phase of the thermodynamic operating cycle, -- the admission of the gas into cylinder (1) is closed as soon as The maximum volume of the active chamber (CA) is reached, the quantity of pressurized gas contained in said active chamber (CA) then expands by pushing the piston (2) on the second part of its stroke which determines the expansion chamber (CD) by producing work corresponding to the polytropic expansion phase of the thermodynamic operating cycle, -- once the piston (2) has reached its bottom dead center, the exhaust port is then opened to carry out the exhaust phase (7) of the thermodynamic operating cycle during the upward movement of the piston over its entire stroke up to its top dead center, -- the engine torque and speed are controlled by the opening and closing of the intake valve by allowing the intake valve to open substantially at top dead center of the piston stroke, and by allowing, by closing the valve, modification of the duration and / or angular sector of the intake, as well as the passage area of ​​the intake opening in order, as a function of the pressure of the compressed gas contained in the storage tank (12) and the pressure at the end of the expansion phase, to determine the quantity of pressurized gas admitted as well as the volume of the active chamber (CA), characterized in that: - a) the exhaust valve (9) is mounted to move axially between a lower closed position in which it is in a tight seal against its exhaust valve seat (20), and a higher open position, - b) in the direction of its opening, the exhaust valve (9) moves axially, in the direction corresponding to that of the flow of pressurized gas out of the cylinder (1), -c) in its closed position, the intake valve is held closed on its exhaust valve seat (20) by a spring (13), - d) the axial forces acting on the exhaust valve (9) resulting from the pressure in the exhaust duct (8) and in the cylinder (1) are permanently balanced, - e) the engine includes a pneumatic cylinder (V) for controlling the opening of the exhaust valve (9), substantially at the bottom dead center of the piston stroke (2), to cause the exhaust valve (9) to detach from its seat (20) to carry out the exhaust phase (7) of the thermodynamic operating cycle during the upward movement of the piston over its entire stroke up to its top dead center, the valve then traveling its complete opening stroke against the force exerted by the return spring (13), Tl - f) the pneumatic cylinder (V) comprises a cylinder and a piston (P) which is connected to the exhaust valve (3) and which delimits a pilot chamber (100) which is connected to a low-pressure gas source (10), - g) the engine includes a channel (X1) which connects the low-pressure gas source (10) to the pilot chamber (100), and a valve (A) controlled for admitting low-pressure gas into the pilot chamber (100), - i) the engine includes an exhaust valve closing control channel (X2) which connects the pilot chamber (100) to the open air or to an energy recovery system (11), and a controlled pilot chamber drain valve (B), and in that, to deactivate said at least one cylinder during one crankshaft rotation, from one piston passage through top dead center (TDC) until the next piston passage through top dead center (TDC): - the intake valve is kept closed to block the intake of pressurized gas into the cylinder (1) during said rotation; - and, simultaneously during said rotation, the exhaust valve is kept open in a state known as cylinder deactivation.

2. Engine according to claim 1, characterized in that, during the first half of said at least one revolution, air at atmospheric pressure is drawn in through the exhaust duct (8) which, during the second half of said at least one revolution, is then drained out of the cylinder (1) through the exhaust duct (8).

3. Engine according to one of claims 1 or 2, characterized in that said at least one cylinder is deactivated during several successive rotations of the crankshaft.

4. Engine characterized in that it comprises at least two cylinders (1) of which each piston (5) drives the same crankshaft by means of a traditional connecting rod-crank device (3,4), and of which each cylinder is made according to one of claims 1 to 3, and characterized in that during said at least one revolution of one of said at least two cylinders during which it is deactivated, another of said at least two cylinders is an active cylinder operating according to said three-phase thermodynamic cycle.

5. Engine according to claim 4, characterized in that it comprises at least three cylinders (1), each piston (5) of which drives the same crankshaft by means of a conventional connecting rod-crank device (3, 4), and each cylinder of which is made according to any one of claims 1 to 3, and characterized in that during said at least one revolution of one of said at least three cylinders during which it is deactivated, the at least two other cylinders are active cylinders operating according to the said three-phase thermodynamic cycle.

6. Engine according to claim 1, characterized in that the low pressure gas source is a pressure regulator (10) whose inlet is connected to the high pressure storage tank (12) or to the intake duct, and whose outlet is connected to the pilot chamber (100).

7. Engine according to claim 2, characterized in that the regulator (10) is a regulator with variable outlet pressure controlled to vary the value of the lift of the exhaust valve (9) from its seat (20).

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