AIR MOTOR WITH INTEGRATED ACTIVE CHAMBER AND ACTIVE DISTRIBUTION WITH BALANCED VALVE

Description

Technical field of the invention

[0001] The invention relates to an engine operating in particular with compressed air, or any other gas, and using a chamber called an "active chamber".

[0002] The invention relates to the intake distribution of such an engine and more particularly for an engine comprising an included active chamber, and especially for a multimodal self-expanding engine with an included active chamber. Technical background

[0003] The distribution system refers to all the means used to supply such an engine with compressed gas.

[0004] The inventors and / or the applicant have filed numerous patents relating to engines and their installations, using gases and more particularly compressed air for completely clean operation in urban and suburban areas.

[0005] In particular, they have filed an international patent application WO-A1-03 / 036088, the contents of which can be referenced, concerning a motor-compressor - motor-alternator group with additional compressed air injection that can operate in so-called single-energy mode, and in so-called multi-energy mode.

[0006] In these types of engines operating with compressed air and having a compressed air storage tank, it is necessary to reduce 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).

[0007] To solve the regulator problems, the inventors and / or the applicant have also filed a patent application WO-A1-03 / 089764, the contents of which may be referenced, concerning a dynamic variable flow regulator and distribution for engines supplied with compressed air injection, comprising a high-pressure compressed air reservoir and a working capacity.

[0008] In the operation of these "load expansion" engines, the filling of the expansion chamber always represents a work-free expansion which is detrimental to the overall efficiency of the machine.

[0009] 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 preferably supplied by compressed air, or by any other compressed gas, contained in a high-pressure storage tank, previously depressurized to a nominal working pressure in a buffer capacity called the working capacity.

[0010] In this type of engine, according to the teachings of document WO-A1-2005 / 049968: The expansion chamber consists of a variable volume equipped with means to produce work; it is twinned and in contact by a permanent passage with the space above the main power piston, which is equipped with a device to stop the piston at its top dead center; during the stopping of the power piston's stroke at its top dead center, air or gas under pressure is admitted into the expansion chamber when it is at its smallest volume and, under pressure, will increase its volume by producing work; the expansion chamber being maintained substantially at its maximum volume, the compressed air contained therein then expands in the power cylinder, thus pushing the power piston in its downward stroke, in turn providing work; during the upward movement of the power piston during the exhaust stroke, the variable volume of the expansion chamber is returned to its smallest volume to restart a complete work cycle.

[0011] The expansion chamber of the engine according to this invention actively participates in the work. The engine is thus called an "active chamber" engine.

[0012] Document WO-A1-2005 / 049968 describes, in particular, a four-phase thermodynamic cycle during its operation in single-energy compressed air mode, characterized by: an isothermal expansion without work; a transfer - slight expansion with work called quasi-isothermal; a polytropic expansion with work; an escape at ambient pressure.

[0013] Document WO-A1-2008 / 028881, which presents a variant of the teachings of document WO-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.

[0014] According to the teachings of documents WO-A1-2005 / 049968 and WO-A1-2008 / 028881, the engines are called "active chamber engines".

[0015] Subsequently, the inventors and / or the applicant filed a patent application for an air or compressed gas engine with an included active chamber that 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.

[0016] According to the teachings of document WO-A1-2012 / 045693, the inventors proposed an engine with an enclosed active chamber, comprising at least one piston mounted to slide within 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: an isothermal expansion without work: a transfer - slight expansion with work called quasi-isothermal; a polytropic expansion with work: an escape at ambient pressure.

[0017] Preferably supplied by compressed air, or any other compressed gas, contained in a high-pressure storage tank, through a buffer tank called the working tank 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 the working pressure in a working tank preferably through a dynamic pressure-reducing device, in which: the active chamber is included / incorporated in the engine cylinder; the engine cylinder comprises at least one piston mounted to slide in at least one cylinder whose volume swept by the piston is divided into two distinct parts, the first part constituting the active chamber CA and the second part constituting the expansion chamber CD; the cylinder is closed at its upper part by a cylinder head comprising at least one intake duct and port, and at least one exhaust duct and port, 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;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 and which, under the continuous pressure of the compressed air at constant working pressure, will increase its volume by producing work representing the quasi-isothermal transfer phase; 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, contained in said active chamber then expands by pushing the piston on the second part of the stroke which defines the expansion chamber CD, producing work thus ensuring the expansion phase; the piston having reached its bottom dead center, the exhaust port is then opened to ensure the exhaust phase during the upward movement of the piston over its entire stroke.

[0018] The volume of the active chamber (CA) and the volume of the expansion chamber (CD) are sized so that, at the engine's nominal operating pressure, the pressure at the end of the expansion stroke at bottom dead center is close to ambient pressure, particularly atmospheric pressure. The volume of the active chamber is determined by the intake valve closure.

[0019] Advantageously, and especially in single-energy operation with compressed air, the engine with included active chamber described above comprises several successive cylinders of increasing displacements.

[0020] Preferably, the engine is supplied, in accordance with the teachings of documents WO-A1-2005 / 049968 and WO-A1-2008 / 028881, by compressed air, or by any other compressed gas, contained in a high-pressure storage tank, previously depressurized, to a nominal working pressure, in a buffer capacity - called working capacity.

[0021] 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 down to a nominal working pressure and this expansion operation either results in a loss of efficiency by the use of a conventional regulator 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.

[0022] The inventors and / or the applicant then filed a new patent application WO-A1-2012 / 045694, the contents of which may be referenced, which claims a compressed air engine with an enclosed active chamber in which: the high-pressure compressed air storage tank, or any other pressurized gas, directly supplies the intake of the engine cylinder; the filling of the included active chamber CA is carried out at a constant intake pressure at each engine revolution, this intake pressure being degressive as the pressure in the storage tank decreases as this tank is progressively emptied: the volume of the included active chamber CA is variable and is progressively increased as the pressure in the storage tank which determines said intake pressure decreases;The means for opening and closing the compressed air intake into the included active chamber CA not only allow the intake orifice and duct to be opened substantially at top dead center of the piston stroke, but also allow the duration and / or angular sector of the intake to be modified, as well as the passage cross-section of the opening; the volume of the included active chamber CA is sized for the maximum storage pressure, then it is progressively 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 the expansion before the exhaust opening is close to atmospheric pressure.

[0023] The motor according to WO-A1-2012 / 045694 also functions as a regulator, the invention thus making it possible to propose a so-called "self-regulating" motor which, for supplying the active chamber CA, does not require any independent regulator of any type.

[0024] The multimodal self-expanding motor with an included active chamber, as described in document WO-At-2012 / 045694, notably implements, during its operation in single-energy compressed air mode, a three-phase thermodynamic cycle comprising: an isobaric and isothermal transfer phase, a polytropic expansion phase with work, an escape phase at ambient pressure.

[0025] In the operation of this engine, the volume of the active chamber, which varies according to the pressure of the high-pressure storage tank, determines the amount of compressed air injected. The higher the intake pressure, the smaller the volume of the active chamber must be.

[0026] In order to obtain correct operation in all phases of engine use, it is therefore necessary to supply it with great precision according to various parameters including speed or rotational speed, supply pressure, load determined by the position of the accelerator, and temperature.

[0027] To achieve this, it is necessary to be able to vary: the timing of the intake opening 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, the timing of the intake closing, depending on the engine speed, but also the intake pressure, the lift of the intake valve depending on the desired load.

[0028] The difficulty lies in the realization of the means of opening and closing the intake of compressed air into the included active chamber which not only allow the orifice 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 cross-section of the opening.

[0029] The distribution of engines of all types is generally ensured by valves whose operation is well known.

[0030] Thus, a valve closes the intake and / or exhaust duct and it has a valve head held by one or more springs resting 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.

[0031] The valve head opens the circuit by entering the chamber to be supplied, driven by mechanical systems of cam and pushrods acting on the stem or rod of the valve which extends from the valve head.

[0032] In other areas of engine technology, and for other technical reasons, particularly regarding pollution reduction and the control of intake and exhaust in conventional combustion engines, many engine manufacturers are working on systems to control the timing and duration of valve openings during operation and have filed numerous patents for these applications. Complex mechanical systems driven by electric stepper motors have also been developed and marketed, notably by BMW (Registered Trademark) with the "Vamos" system.

[0033] 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.

[0034] Much work has been undertaken on electromechanical devices, in particular those controlled by easily controllable electromagnets to take into account the various operating parameters, but the electrical powers required to enable the accelerations and the speed of movement of the valves require considerable power, given the weight and inertia of the latter.

[0035] To solve the problems mentioned above while providing an increase in power, the inventors and / or the applicant filed patent application WO-A2-2015 / 117076 concerning a compressed air engine with an included active chamber and active intake distribution.

[0036] 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 which supplies the active chamber of the engine, the compressed air which has been used for these actions is then reused in the engine to produce additional work.

[0037] Thus, an active chamber engine operating according to a three-phase thermodynamic cycle has been proposed, comprising: an isobaric and isothermal transfer phase; a polytropic expansion phase with work; an escape phase at ambient pressure; this engine includes: at least one cylinder supplied with pressurized gas, preferably compressed air, contained in a high-pressure storage tank, at least one piston which is mounted to slide within this cylinder, a crankshaft driven by the piston by means of a traditional connecting rod-crank device, a cylinder head which closes at its upper part the volume of the cylinder, which is swept by the piston, and which has at least one intake port through which flows a stream of pressurized gas to fill the cylinder, a pressurized gas intake port above the piston, and at least one exhaust port and an exhaust port, 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 design, reduced to only the minimum clearances allowing operation without contact between the piston and the cylinder head,at least one intake valve that seals tightly with a valve seat formed in the cylinder head and that defines the intake port, engine in which: -- The volume of the cylinder swept by the piston is divided into two distinct parts: the first part constitutes an active chamber, which is included within the cylinder, and the second part constitutes an expansion chamber. -- Under the continuous pressure of the gas admitted into the cylinder, at constant working pressure, the volume of the active chamber increases, producing work that represents the isobaric and isothermal transfer phase. -- The admission of the gas under pressure into the cylinder is closed as soon as the maximum volume of the active chamber is reached. The quantity of gas under pressure contained in said active chamber then expands, pushing the piston through the second part of its stroke, which defines the expansion chamber, producing work that ensures the polytropic expansion phase. -- The piston having reached its bottom dead center,The exhaust port is then opened to ensure the exhaust phase during the piston's upward movement throughout its entire stroke up to top dead center. Engine torque and speed are controlled by the opening and closing of the intake valve. This allows the intake valve to be opened approximately at top dead center of the piston stroke, and by closing the valve, the duration and / or angular sector of the intake stroke, as well as the cross-sectional area of ​​the intake opening, to be modified in order to determine, based on the pressure of the compressed gas contained in the storage tank and the pressure at the end of the expansion phase, the quantity of pressurized gas admitted and the volume of the active chamber. in which: a) The intake valve is mounted to move axially between a closed lower position, in which it bears a tight seal on its valve seat, and an open upper position; b) in the direction of its opening, the intake valve moves axially in the opposite direction to the flow of pressurized gas filling the cylinder; c) in its closed position, the intake valve is held closed in an autoclave on its valve seat by the pressure in the intake duct acting on the intake valve; d) the engine includes means for controlling the opening of the intake valve, substantially at top dead center of the piston stroke, to cause the intake valve to lift off its seat and allow the intake pressure to build up in the active chamber.the valve then travels 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, e) the engine includes a pneumatic cylinder for closing the intake valve which comprises a cylinder and a closing piston which is axially linked with the intake valve, and which is slidably mounted in the cylinder within which it hermetically seals a control chamber for the cylinder, called the closing chamber, f) the engine includes at least one control channel for opening the intake valve 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,(g) The engine includes an active distribution channel which connects said closing chamber to the upper part of the active chamber and a valve for shutting off the gas circulation in the active distribution channel, called the active distribution valve, the opening of which is controlled to bring the closing chamber into communication with the upper part of the active chamber, close the intake valve and produce work which is added to the work of the pressurized gas charge previously admitted, via the intake duct, into the active chamber.

[0038] You can refer to the contents of this document to learn more about the other characteristics of the engine.

[0039] The invention aims to propose a new design of such an active chamber compressed air engine, in particular aimed at increasing its performance and efficiency, notably by using a distribution system for controlling the opening and closing of the intake 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.

[0040] The "pneumatic" energy required to open and close the intake valve is supplied, for example, in the form of gas from the high-pressure storage tank or from the intake circuit, which is depressurized to low pressure. After being used to control the valve opening, this energy can then be reused to produce additional work.

[0041] The volumes of the closing and / or opening chambers are of reduced value, for example, non-limiting, less than 10% of the engine displacement

[0042] The same applies to the conduits connecting the inlet and the active chamber, the inlet and the closing chamber, the closing chamber and the expansion chamber are calculated to allow sufficient flow to establish pressures in the different active chambers.

[0043] The invention applies identically to the control of an exhaust valve. Summary of the invention

[0044] The invention proposes an active chamber engine operating according to a three-phase thermodynamic cycle comprising: an isobaric and isothermal transfer phase; a polytropic expansion phase with work; an escape phase at ambient pressure; this engine includes: at least one cylinder supplied with pressurized gas, preferably compressed air, contained in a high-pressure storage tank, at least one piston which is mounted to slide within this cylinder, a crankshaft driven by the piston by means of a traditional connecting rod-crank device, a cylinder head which closes at its upper part the volume of the cylinder which is swept by the piston, and which includes at least one intake port through which flows a stream of pressurized gas to fill the cylinder, a pressurized gas intake port above the piston, and at least one exhaust port and an exhaust port, 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,at least one intake valve that seals tightly with a valve seat formed in the cylinder head and that defines the intake port, engine in which: -- The volume of the cylinder swept by the piston is divided into two distinct parts: the first part constitutes an active chamber, which is included within the cylinder, and the second part constitutes an expansion chamber. -- Under the continuous pressure of the 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. -- The admission of the gas under pressure into the cylinder is closed as soon as the maximum volume of the active chamber is reached. The quantity of gas under pressure contained in said active chamber then expands, pushing the piston through the second part of its stroke, which defines the expansion chamber, producing work corresponding to the polytropic expansion phase of the thermodynamic operating cycle. -- 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 piston's upward movement through its entire stroke to top dead center. Engine torque and speed are controlled by opening and closing the intake valve. This allows the intake valve to be opened approximately at top dead center of the piston stroke, and by closing the valve, the duration and / or angular sector of the intake stroke, as well as the cross-sectional area of ​​the intake opening, to be modified in order to determine, based on the pressure of the compressed gas contained in the storage tank and the pressure at the end of the expansion phase, the quantity of pressurized gas admitted and the volume of the active chamber. characterized in that: a) The intake valve is mounted to move axially between a closed lower position, in which it bears a tight seal against its valve seat, and an open upper position; b) in the direction of its opening, the intake valve moves axially in the opposite direction to the flow of pressurized gas filling the cylinder; c) in its closed position, the intake valve is held closed against its seat by a spring; d) the axial forces acting on the intake valve resulting from the pressure in the intake manifold and the cylinder are constantly balanced; e) the engine includes a pneumatic actuator to control the opening of the intake valve, substantially at top dead center of the piston stroke, to lift the intake valve from its seat and allow the intake pressure to build up in the active chamber.the valve then travels its full opening stroke against the force exerted by the return spring, f) the pneumatic cylinder comprises a cylinder and a piston which is connected to the inlet valve and which delimits a pilot chamber which is connected to a low-pressure gas source which is a pressure regulator whose inlet is connected to the high-pressure storage tank or the inlet duct, and whose outlet is connected to the pilot chamber, g) the motor comprises a channel which connects the low-pressure gas source to the pilot chamber, and a controlled valve for admitting low-pressure gas into the pilot chamber, i) the motor comprises a control channel for closing the inlet valve which connects the pilot chamber to the atmosphere or to an energy recovery system, and a controlled valve for draining the pilot chamber.

[0045] According to other engine characteristics: The pressure regulator is a variable outlet pressure regulator controlled to vary the lift of the intake valve from its seat; the engine includes an energy recovery system, a channel that connects the energy recovery system to the upper part of the cylinder located above the piston, and an active drain valve for the energy recovery system in the upper part of the cylinder; the intake, drain, and active drain valves are controlled according to the following cycle: i) opening of the intake valve to bring the pilot chamber into communication with the low-pressure gas source and causing the intake valve to open around top dead center of the piston to bring the intake duct into communication with the active chamber of the cylinder,ii) closure of the intake valve and opening of the drain valve when the piston reaches the required limit of the active chamber to cause a drop in pressure in the pilot chamber and to cause the intake valve to close; iii) closure of the valve and, when the pressure in the cylinder is less than or equal to the pressure in the energy recovery system, opening of the active drain valve to introduce into the cylinder a charge that is added to the charge previously admitted into the active chamber; iv) closure of the active drain valve during the upward stroke of the piston; the pneumatic cylinder controlling the opening of the intake valve is integrated into the cylinder head and its piston is integral with the intake valve stem; the pneumatic cylinder controlling the opening of the intake valve is arranged outside the cylinder head, and in that the output member of the cylinder is connected,directly or indirectly, to the intake valve stem by a motion transmission element; the pneumatic actuator for controlling the opening of the intake valve is a pneumatic muscle, and in that said motion transmission element is a rocker arm mounted to pivot about an axis orthogonal to the sliding axis of the intake valve, one end of which is connected, directly or indirectly, to the intake valve stem, and the other opposite end is connected to the output member of the pneumatic control actuator; the position of the pivot axis of the rocker arm is adjustable between its two opposite ends; the intake valve stem is traversed axially by a pressure balancing channel which opens into a compensation chamber and into the upper part of the cylinder. Brief description of the figures

[0046] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which: [ Fig. 1A ] - there 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; Fig. 1B ] - there figure 1B is a view analogous to that of the Figure 1A on which the engine is illustrated during intake, at its top dead center, the intake valve having been opened from top dead center; [ Fig. 1C ] - there figure 1C is a view analogous to those of Figures 1A And 1B on which the engine is shown during the expansion phase; [ Fig. 2 ] - there figure 2 is a view analogous to that of the Figure 1Awhich illustrates a second embodiment of an engine according to the invention; [ Fig.3 - the figure is a view analogous to that of the Figure 1A which illustrates a third embodiment of an engine according to the invention; [ Fig. 4 ] - there figure 4 is a view analogous to that of the figure 3 which illustrates a variant of the third embodiment; [ Fig. 5 ] - there figure 4 is a view analogous to that of the figure 3 which illustrates another variant of the third embodiment; [ Fig. 6 ] - there figure 6 is an axial cross-sectional view of an example of a modular cartridge incorporating a valve suitable for integration into an engine of the type schematically illustrated in figures 3 And 4 ; Fig. 7 ] - there figure 7is a cross-sectional view through a plane passing through the axes of an intake valve and an exhaust valve of an example of an engine of the type schematically illustrated in figures 3 And 4 in which each valve is integrated into a cartridge as illustrated in the figure 6 ; Fig. 8 ] - there figure 8 is a top perspective view of an example of an embodiment of a piston particularly suited to the design of an engine according to the invention. Detailed description of the invention

[0047] The engine has one or more cylinders, of which only one 1 is shown, which is supplied with a pressurized gas, preferably compressed air, contained in a high-pressure storage tank 12.

[0048] The engine includes a piston 2 which is mounted to slide 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 a connecting rod 3 and a crank 4.

[0049] 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.

[0050] 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: a first upper part constituting the active chamber CA, which is thus included in cylinder 1; and a second lower part constituting the expansion chamber CD.

[0051] The cylinder head 6 includes at least one intake duct 8 which is connected to the reservoir 12 and into which flows the pressurized gas for filling cylinder 1,

[0052] The intake duct 8 terminates at its lower end with an intake orifice 7 for pressurized gas arranged above the piston 2.

[0053] 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.

[0054] To open or close the intake port 7, the cylinder head 6 has an intake valve 9, which is particularly capable of cooperating in a tight manner with a valve seat 20 formed in the cylinder head 6 and which delimits the intake port 7.

[0055] Cylinder head 6 also includes at least one exhaust valve, at least one exhaust port and at least one exhaust duct (not shown), the design and operation of which are similar to the intake system described here in detail.

[0056] In such an engine, the volume of cylinder 1 swept by piston 2 is divided into a chamber called the active chamber CA, which is included in cylinder 1, and a second part constituting an expansion chamber CD: a) under the continuous pressure of the gas admitted into cylinder 1, at constant working pressure, the volume of the active chamber CA increases by producing work corresponding to the first quasi-isothermal transfer phase of the thermodynamic operating cycle; b) the admission of the gas under pressure into cylinder 1 is closed as soon as a chosen maximum volume of the active chamber CA is reached, the quantity of gas under pressure contained in the active chamber CA then expanding by pushing the piston 2 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;c) when piston 2 has reached its bottom dead center (BDC), the exhaust port is opened by actuation of the exhaust valve in order to - during the upward movement of piston 2 through its entire stroke to its top dead center (TDC) - carry out the third exhaust phase of the thermodynamic operating cycle. ;

[0057] The torque supplied by the engine is controlled by the control of the opening and closing of the intake valve 9 by opening it at 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.

[0058] The intake duct 8 is directly connected to the high-pressure gas reservoir 12, which thus directly supplies the active chamber CA. The latter is therefore at the same pressure as the gas contained in the reservoir 12, for example around 100 bar, and is higher than that prevailing in the active chamber CA and the expansion chamber CD, for example equal to 1.5 bar at the time of the cycle corresponding to the bottom dead center BDC of the piston, at the end of the expansion, just before the opening of the exhaust valve.

[0059] The intake valve 9 is guided by sliding motion in a valve guide 206 and is mounted to move axially - along its main axis - between: a low closing or sealing position (considering the general vertical orientation of the figures and without reference to Earth's gravity) which is represented at the Figure 1Aand in which the lower part or head 25 of the valve is in a tight bearing against the valve seat 20; and a high opening position shown in the figure 1B .

[0060] In the direction of its opening, the intake valve 9 moves axially upwards, in the opposite direction to the flow of pressurized gas F filling the cylinder. Thus, the intake valve opens in the opposite direction to the pressurized airflow filling the engine cylinder.

[0061] The engine includes a pneumatic cylinder, or gas spring, V for controlling the opening of the intake valve 9 which, by way of non-limiting example and according to the design illustrated in Figures 1A to 1C , is fitted in cylinder head 6.

[0062] The cylinder V comprises a cylinder and a closing piston P which is linked in axial movement with the upper rod 26 of the inlet valve 9, and which is mounted to slide in the cylinder of the cylinder V inside of which it seals a lower chamber 100, called the opening chamber of the inlet valve 9, or pilot chamber.

[0063] Above the piston P, the cylinder of the actuator has an upper chamber 99 in which is housed an elastic return spring 13 of the intake valve 9 which is for example a helical spring which is mounted compressed in the upper chamber 99 and which exerts an elastic force directed downwards on the upper face 27 of the piston P.

[0064] Above the upper chamber 99 housing the return spring 13, the cylinder of the jack extends by an upper section 98 of smaller diameter in which the upper part of the stem 26 of the intake valve 9 - which extends above the piston P - is received in axial sliding.

[0065] The upper free end face 22 of the stem 26 of the intake valve 9 delimits in the section 98 an upper chamber 101 called the compensation chamber.

[0066] 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 valve 9 over its entire height.

[0067] A channel X1 connects the inlet duct 8 to the lower compensation chamber 100 of the cylinder V.

[0068] The engine includes a controlled valve A, called the intake valve, which is arranged in the channel X1, and whose opening can be controlled to put the intake duct 8 and / or the reservoir 12 in communication with the compensation chamber 100.

[0069] A regulator 10 is interposed in the channel X1, here preferentially upstream of the valve A, to reduce the pressure at the outlet of the regulator 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.

[0070] The regulator 10 can be with constant outlet pressure or, alternatively, with adjustable outlet pressure.

[0071] When the outlet pressure of the regulator is adjustable, controlling its value allows the value of the valve lift to be varied.

[0072] 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 interposition of an energy recovery system 11.

[0073] The motor includes a controlled valve B called the drain valve B of closure 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.

[0074] The engine includes a controlled valve C, called the active drain valve, which connects the upper part of cylinder 1 to the potential energy recovery system 11 and whose opening can be controlled to put the potential energy recovery system 11 with cylinder 1.

[0075] The intake valve 9 is constantly returned to its closed position. As an example, the intake valve 9 is elastically returned and held closed on its valve seat 20 by a return spring 13.

[0076] By its design according to the invention, the intake 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.

[0077] This is achieved thanks to the presence of the upper compensation chamber 101 which is connected to the upper part of cylinder 1 by channel 102.

[0078] It is noted 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.

[0079] The surface area of ​​the upper free end face 22 of the stem 26 of the inlet valve 9 is equivalent to the surface area of ​​the lower face 21 of the head 25 of the inlet valve 9 which is subjected to the same pressure value, thus allowing the effects on the valve resulting from the pressure to be canceled.

[0080] The engine includes a low-pressure distribution system which is connected to the intake duct 8 by the pressure regulator 10 whose outlet pressure value is lower than the pressure of the high-pressure gas contained in the tank 12.

[0081] The maximum pressure value prevailing in the distribution system, downstream of the regulator 10, is constant throughout the progressive emptying of the tank 12.

[0082] This maximum value of the pressure prevailing in the distribution system corresponds at least to obtaining a full lift stroke of the valve 9, but it can vary below this maximum value in order to decrease the stroke of the intake valve 9.

[0083] When piston 2 approaches top dead center TDC of its stroke, the so-called intake valve A opens channel X1 to pressurize pilot chamber 100 by connecting it to the outlet of regulator 10.

[0084] The pilot pressure is then applied to the lower surface 23 of the piston P attached to the stem or tail of the valve 9.

[0085] The force thus applied to the intake 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.

[0086] Valve 9 then travels through its entire opening stroke and puts the intake duct 8 in communication with cylinder 1.

[0087] The threshold 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 valve 9.

[0088] When the piston 2 reaches the point in its axial stroke corresponding to the delimitation of the active chamber DD' (whose axial position is a function of the required torque), 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.

[0089] The decrease 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 continuously by the return spring 13 then cause the intake valve 9 to descend until its head 25 is in tight contact with the valve seat 20.

[0090] The command to open the drain valve B puts the pilot chamber 100 into communication with the potential energy recovery system 11.

[0091] With the intake valve 9 closed, the compressed gas in cylinder 1 expands as piston 2 moves down and its value decreases.

[0092] When the pressure value in cylinder 1 is less than or equal to the pressure value in the potential energy recovery system 11, the closure 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.

[0093] The design of the potential energy recovery system 11 can take several forms, depending on the type of energy one wants to recover, and for example: the form of a potential energy recovery system whose purpose is to reinject into cylinder 1 the pressurized gas used in the active distribution system in order to produce additional mechanical work by means of piston 2 - according to the embodiment illustrated in the figures; or alternatively the form of a potential and kinetic energy recovery system through a turbine system (not shown); or alternatively the form of a thermal energy recovery system (not shown).

[0094] Combining one or more of these energy recovery systems can be considered.

[0095] In the first case illustrated in the figures, the volume of gas recovered and stored in a reservoir 11 is injected into cylinder 1, expanding in the expansion chamber CD of the engine and producing work which is added to the work of expansion of the charge admitted into the active chamber CA. Thus, in the sense of the invention, valve C is an active distribution valve.

[0096] We can therefore understand the operation of the so-called active distribution according to the invention, in which, advantageously, the energy required to control the opening and closing of the intake valve 9 is reused in whole or in part, in various possible forms.

[0097] The exhaust valve and exhaust pipe are not shown in the diagram. figures 1A to 6 , but the whole system works according to the same principle that governs admission.

[0098] The exhaust valve control system can be connected to the same regulator 10 and the same potential energy recovery system 11 as those belonging to the intake valve control system 9. The exhaust valve opening cycle is close to an opening at the bottom dead center of the piston 2 stroke and close to a closing at the top dead center of the piston 2 stroke. Description of the second embodiment

[0099] The following description is made by comparison with the first embodiment previously described with reference to Figures 1A to 1C .

[0100] In the design according to this second embodiment illustrated in the figure 2 We replace the two valves A and B illustrated in Figures 1A to 1C by a spool valve E commonly called a distributor.

[0101] The distributor E is of the two-position, three-way type.

[0102] In its state or position illustrated in the figure, the pilot chamber 100 is connected to the X2 channel upstream of the potential energy recovery system 11.

[0103] A change in the position of the distributor spool causes the outlet of the regulator 10 to communicate with the pilot chamber 100 and interrupts the communication between the pilot chamber 100 and the channel X2. Description of the third embodiment

[0104] The following description is made by comparison with the first embodiment previously described with reference to Figures 1A to 1C .

[0105] In the design according to this third embodiment illustrated in the figure 3 , we highlight the possibility of offsetting the pilot chamber relative to the valve 9 by means of a rocker 14 mechanically linking the intake valve 9 to a pneumatic cylinder V comprising the pilot chamber 100.

[0106] Cylinder V is offset or laterally displaced and can notably be arranged outside the cylinder head 6 as an independent discrete component.

[0107] This design makes it easier to size the V-cylinder and the pilot chamber.

[0108] It also facilitates manufacturing and maintenance, and it helps to limit the inconveniences due to leaks that may be present at the piston P of the cylinder V illustrated according to the first embodiment.

[0109] As a non-limiting example, a V-shaped cylinder for controlling the opening of the valve can be of the so-called "pneumatic muscle" type, in particular the force / stroke behavior of which is almost linear and whose stroke is directly adjustable by adjusting the value of its supply pressure.

[0110] Such a cylinder can be used with a low supply pressure equal to or less than, for example, 8 bar.

[0111] This type of pneumatic muscle (Fluidic Muscle DMSP) is, for example, marketed under the registered trademark "FESTO".

[0112] The rocker 14 is mounted pivoting about an axis 15 which is orthogonal to the sliding axis of the intake valve 9. One of its ends is connected directly or indirectly to the stem 26 of the valve, and its other opposite end is connected to the output member 17 of the offset cylinder V.

[0113] According to a first variant and as illustrated in the figure 4 We can replace both valves A and B of the figure 3 by a valve or spool distributor E.

[0114] According to another variant, and as illustrated in the figure 5 , and by comparison with the embodiment previously described with reference to the figure 3We have represented the possibility of adjusting the position of the pivot axis 15 of the rocker arm 14 and thus varying the stroke of the valve 9 according to the different phases of engine operation. Description of a cartridge incorporating a valve

[0115] We represented at the figure 6 a cartridge 200 comprising a two-part lower 202 and upper 204 housing which accommodate an external valve guide 206 which guides the sliding stem 26 of a valve 9 whose lower head 25 is illustrated opposite a valve seat 20 integrated into the lower part 202 of the cartridge 200 housing.

[0116] The inlet orifice 7 is formed in the lower part 202 of the cartridge housing and is cylindrical with a circular cross-section.

[0117] 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.

[0118] According to 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 opposite lower face portion 209 of the internal guide 207.

[0119] The external guide 206 and the lower part 202 of the housing are crossed by venting passages 210.

[0120] To the figure 6 , valve 9 is illustrated in its maximum high position corresponding to the control of its full opening.

[0121] 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 is axially supported upwards.

[0122] The hollow piston P, integral with the rod 25, is capable of axial sliding in both directions - between its upper position illustrated in the figure 6and its low position in which the head 25 is axially supported downwards against the seat 20 (See figure 7 ) - by a rocker 14 which is mounted pivoting around a fixed axis 15 carried by the upper part 204 of the cartridge housing 200.

[0123] The free end 214 of the rocker 14 is suitable for being articulated to the output rod of an actuator or control cylinder, which is, for example, a pneumatic muscle as illustrated in the figure 7 . Description of figure 7 incorporating a title block "admission" » and an "escape" cartridge »

[0124] To the figure 7 which has a general symmetry with respect to a median vertical plane, on the left side an intake cartridge 200 and on the right side an exhaust cartridge 200' whose components are all designated by the same numerical references augmented by the index "prime". Description of the piston in Figure 8

[0125] According to the invention, the cylinder head 6 is designed and 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.

[0126] There figure 8 illustrates an example of piston design 2 particularly suited to achieving this result.

[0127] For this purpose, the upper face 30 of the piston is a flat face which extends in a plane orthogonal to the axis of sliding of the piston and - when the piston 2 is at its top dead center TDC corresponding to zero degree of angle of the crankshaft - this upper face is thus able to be adjacent, almost without axial play, to the lower face 32 opposite the cylinder head 6.

[0128] In order to "fill" each dead volume corresponding to each intake orifice 7 (or exhaust orifice 7') the upper face 30 has protruding pins or fingers 220 (220') each of which is dimensioned (in diameter and height) to be received in an intake orifice 7 (7').

[0129] The example illustrated in the figure 8 has two 220 fingers for two intake ports and two 220' fingers for two 7' exhaust ports.

Claims

1. Active chamber engine operating according to a three-phase thermodynamic cycle comprising: - an isobaric and isothermal transfer phase; - a polytropic expansion phase with work; - an exhaust phase at ambient pressure; this engine comprising: - at least one cylinder (1) supplied with pressurised gas, preferably compressed air, contained in a high-pressure storage tank (12), - at least one piston (2) which is mounted so as to slide in this cylinder (1), a crankshaft (5) driven by the piston by means of a conventional connecting rod-crank device (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 comprises at least one inlet duct (8) in which a flow of pressurised gas fills the cylinder, an inlet orifice (7) for the pressurised gas above the piston, and at least one exhaust port and one exhaust duct, the cylinder head being arranged such that, when the piston (2) is at its top dead centre, the residual volume between the piston (2) and the cylinder head (6) is, by design, reduced to the minimum clearance necessary to allow operation without contact between the piston (2) and the cylinder head (6), - at least one intake valve (9) which cooperates in a sealed manner with a valve seat (20) formed in the cylinder head (6) and which delimits the intake port (7), engine in which: -- the volume of the cylinder (1) swept by the piston (2) is divided into two distinct parts, a first part constituting an active chamber (CA) which is included in the cylinder (1) and a second part constituting an expansion chamber (CD), -- under the continuous thrust of the pressurised gas admitted into the 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 pressurised gas into the cylinder (1) is shut off as soon as the maximum volume of the active chamber (CA) is reached, the pre d amount of pressurised gas contained in said active chamber (CA) then expands, pushing the piston (2) back over the second part of its stroke, which determines the expansion chamber (CD), producing work corresponding to the polytropic expansion phase of the thermodynamic operating cycle, -- once the piston (2) has reached its bottom dead centre, the exhaust port is then opened to perform the exhaust phase (7) of the thermodynamic operating cycle during the piston's upward movement over its entire stroke until it reaches its top dead centre, -- the torque and speed of the engine are controlled by the opening and closing of the intake valve (9), allowing the intake valve (9) to be opened at approximately top dead centre of the piston stroke and, by closing the valve (9), modify the duration and / or angular sector of the intake, as well as the passage section of the intake opening in order to determine, depending on the pressure of the compressed gas contained in the storage tank (12) and the pressure at the end of the expansion phase, the quantity of pressurised gas admitted and the volume of the active chamber (CA), characterised in that: - a) the intake valve (9) is mounted so as to be movable axially between a lower closed position in which it rests tightly against its valve seat (20) and an upper open position, - b) in the direction of its opening, the inlet valve (9) moves axially in the opposite direction to that of the flow of pressurised gas filling the cylinder (1), - c) in its closed position, the inlet valve (9) is held closed on its seat (20) by a spring (13), - d) the axial forces exerted on the intake valve (9) resulting from the pressure prevailing in the intake duct (8) and in the cylinder (1) are permanently balanced, - e) the engine comprises a pneumatic cylinder (V) for controlling the opening of the intake valve (9), substantially at the top dead centre of the piston stroke (2), to cause the intake valve (9) to lift off its seat (20) to allow the intake pressure to be established in the active chamber (CA), the valve then travelling its full opening stroke against the force exerted by the return spring (13), - f) the pneumatic cylinder (V) comprises a cylinder barrel and a piston (P) which is connected to the intake valve (3) and which delimits a control chamber (100) which is connected to a source (10) of low-pressure gas which is a pressure regulator with variable outlet pressure controlled to vary the amount of lift of the inlet valve (9) from its seat (20), - g) the engine comprises a channel (X1) connecting the low-pressure gas source (10) to the pilot chamber (100), and a valve (A) controlling the admission of low-pressure gas into the pilot chamber (100), - i) the engine comprises a channel (X2) for controlling the closure of the intake valve (9), which connects the pilot chamber (100) to the open air or to an energy recovery system (11), and a controlled valve (B) for draining the pilot chamber.

2. Engine according to claim 1, characterised in that the pressure reducer (10) is a pressure reducer with variable outlet pressure controlled to vary the lift of the intake valve (9) from its seat (20).

3. Engine according to any of the preceding claims, characterised in that it comprises an energy recovery system (11), a channel (X3) connecting the energy recovery system (11) to the upper part of the cylinder (1) located above the piston (2), and an active drain valve (C) for the energy recovery system in the upper part of the cylinder (1).

4. Engine according to claim 3, characterised in that the intake (A), drain (B) and active drain (C) valves are controlled according to the following cycle: - i) opening of the intake valve (A) to connect the control chamber (100) to the low-pressure gas source (10) and cause the intake valve (9) to open around the top dead centre of the piston (B) to connect the intake duct (8) to the active chamber (CA) of the cylinder (1), ii) closing the inlet valve (A) and opening the exhaust valve (B) when the piston (2) reaches the limit (DD') as applied to the active chamber (CA) to cause a drop in pressure in the control chamber (100) and to cause the inlet valve (9) to close - iii) closing the valve (B) and, when the pressure in the cylinder (1) is less than or equal to the pressure in the energy recovery system (11), opening the active drain valve (C) to introduce into the cylinder (1) a load that is added to the load previously admitted into the active chamber (CA), - iv) closing the active drain valve (C) when the piston (2) rises.

5. Engine according to claim 1, characterised in that the pneumatic cylinder (V) for controlling the opening of the intake valve (9) is integrated into the cylinder head (6) and its piston (P) is integral with the stem (26) of the intake valve (9).

6. Engine according to claim 1, characterised in that the pneumatic cylinder (V) for controlling the opening of the intake valve (9) is arranged outside the cylinder head, and in that the output member (17) of the cylinder is connected, directly or indirectly, to the stem (26) of the intake valve (9) by a motion transmission member (14).

7. Engine according to claim 6, characterised in that the pneumatic cylinder (V) controlling the opening of the intake valve (9) is a pneumatic muscle, and in that the said motion transmission member is a rocker (14) which is mounted so as to pivot about an axis (15) which is orthogonal to the sliding axis of the intake valve (9), one end of which is connected, directly or indirectly, to the stem (26) of the intake valve (9), and the other opposite end is connected to the output member (17) of the pneumatic control cylinder.

8. Engine according to claim 7, characterised in that the position of the rocker pivot axis (15) is adjustable between its two opposite ends.

9. Engine according to any of the preceding claims, characterised in that the intake valve stem (26) is traversed axially by a pressure equalisation channel (102) which opens into a compensation chamber (101) and into the upper part of the cylinder (1).