Electronic injection device for a compressed-air engine, compressed-air engine provided with such a device and hybrid drive train comprising such an engine

Abstract

The invention relates to an electronic compressed-air injection device for a compressed-air piston engine. The device comprises a compressed-air intake valve (S) comprising: - a bar (20) sliding in a channel perpendicular to the air intake passage admitting air into the chamber of the piston, the bar comprising a first part (21) provided with an intake orifice (210, 211), - a return means (40) for returning the bar (20) and, - at least one actuator (50) controllable by a control unit for moving the bar (20) between an open position in which the intake passage (110, 111) is open, in which position said intake orifice (210, 211) is entirely aligned with said intake passage (110, 111), and a closed position in which said intake orifice (210, 211) is entirely offset with respect to said intake passage (110, 111).

Description

Electronic injection device for a compressed air engine, compressed air engine equipped with such a device and hybrid drive train comprising such an engine.

[0001] The present invention relates to a compressed air engine with low air consumption, and a compressed air injection cycle in this engine, designed according to the known principle of so-called "two-stroke" or "four-stroke" internal combustion engines of "diesel" or "gasoline" engines.

[0002] It also relates to an injection device for such an engine, a cylinder head incorporating this injection device and a hybrid powertrain comprising such an engine.

[0003] The invention finds a particularly important, although not exclusive, application in the field of motorization of land vehicles (such as cars or utility vehicles) or marine vehicles (such as boats), but also for motorization used in industry or for industrial activities such as, for example, generator sets.

[0004] A particularly interesting application of the motor according to the present invention, given solely by way of non-limiting example, is found in the integration of this motor in a drive chain comprising an electric generator engaged with the shaft of the motor, the generator being connected to an electric motor.

[0005] Indeed, there are many powertrain solutions based on thermal engines, electric motors or a combination of the two (called hybrid powertrain).

[0006] So-called "thermal" vehicles require the use of polluting fossil fuels, which has led authorities in many countries to favor other, less polluting types of powertrains. Their main advantage comes from their autonomy and the speed at which the fuel tank can be refilled.

[0007] So-called "electric" vehicles have a drive train composed of a power battery capable of supplying the electric motor(s) capable of driving a transmission connected to a moving part (the wheels of a car or the propeller of a boat, for example).

[0008] A power battery is distinguished from a vehicle's starter battery by its power, capacity, and ability to drive a vehicle's wheels or propeller.

[0009] The power batteries used in electric vehicles are most often lithium-ion batteries, because only this type of battery provides the power and autonomy suitable for this use.

[0010] The major disadvantage of the electric drive train lies precisely in the battery.

[0011] Indeed, its manufacture and end of life are ecologically problematic: reserves of lithium, cobalt and other constituents are theoretically insufficient to equip all the vehicles in the world, and recycling processes are currently unknown or non-operational.

[0012] In addition, lithium-ion batteries have a definite tendency to heat up during charging, or even during use, and many incidents have been recorded in which batteries have caught fire due to this overheating.

[0013] Hybrid powertrains have also been proposed, in which a thermal engine either assists the electric motor, recharges the power battery, or both.

[0014] These hybrid vehicles, however, have all the drawbacks of both technologies: pollution, risk of fire, complex or even impossible recycling, etc.

[0015] There is therefore a need to offer an engine and a drive train that reduce the pollution generated and operating risks.

[0016] A classic two-stroke air-powered piston engine is already known, and illustrated in.

[0017] The engine comprises a cylinder block A comprising at least one piston 1 connected to a drive shaft 2 by means of a connecting rod 3 rotatably attached to a counterweight 4. The piston 1 is mounted to move in translation (arrow F1) in a compression / extension chamber 5, the upper end of which is closed by a cylinder head B. In the lower part, the chamber 5 comprises an opening 6 for admitting outside air (arrow F2), as well as a channel 7 for conducting outside air (arrows F3 and F4) opening into the chamber 5 above the piston 1 when the latter is at bottom dead center. The chamber 5 also comprises an exhaust outlet 12 for discharging the expanded compressed air when the piston descends and is located close to its bottom dead center.

[0018] In the upper part, hermetically closing the chamber 5, the cylinder head B comprises at least one compressed air intake valve 8 from (arrow F5) a high-pressure compressed air reserve 9 via a pressure reducer 10 (aimed at reducing the air pressure of 300 bars or more coming from the reserve to a pressure of 30 to 50 bars at the outlet to the compressed air intake duct 11 located upstream of the intake valve 8). The compressed air intake valve 8 comprises a valve stem 8a, movable in translation (arrow F1) relative to the cylinder head B, and provided with a valve head 8b carrying a contact surface 8c with a valve seat 8d located in the cylinder head B.

[0019] The valve head 8b protrudes into the chamber 5 by a determined length, so that the piston 1 pushes the valve stem upwards. However, for the injected compressed air volume to be sufficient to generate the required engine work, this opening must last a sufficiently long time. Consequently, the valve head must protrude into the chamber by a significant length which, in turn, controls the opening of the valve well before the top dead center of the piston.

[0020] Furthermore, in this type of engine, a volume of outside air, taken at atmospheric pressure when the piston is in the low position (bottom dead center or BDC), is compressed by the piston in the piston chamber when the latter rises. The compressed air heats the walls of the chamber. It is then possible to inject compressed air from the compressed air reserve into this heated chamber via the intake valve. The compressed air then expands due to the pressure difference and the high temperature of the chamber, which forcibly pushes the piston downwards, generating mechanical work and allowing the expanded air to be expelled. Then the cycle resumes: intake of outside air, compression of the air in the chamber by the rising piston and heating of the chamber, injection of compressed air into the chamber, generation of mechanical work, expulsion of the air to the outside.

[0021] By heating chamber 5, this device therefore improves the efficiency of the compressed air by promoting greater and faster expansion, but it still has many defects, particularly when the piston rises.

[0022] Indeed, a first problem lies in the fact that depending on the adiabatic compression ratio of the air, the temperature of the cylinder, when the piston is in the upper position, can exceed several hundred degrees Celsius and the pressure several tens of bars. The external air thus compressed therefore opposes the rise of the piston in the last millimeters, so that the engine loses power.

[0023] Furthermore, compressed air must always be injected at a pressure higher than that of the compressed air in the piston chamber, to allow for expansion and engine work. The compression ratio of the air compressed by the piston, coming from outside, therefore defines the minimum pressure to be injected into the cylinder, which therefore does not allow for fine control, and therefore optimization, of air consumption.

[0024] Thus, a significant part of the piston's rise is opposed by the thrust of the valve and by the pressure of the ambient air compressed by the piston.

[0025] This is all the more true since a compressed air engine differs from a combustion engine in particular by a much larger volume of injected air than the volume of injected fuel, to generate comparable engine work. It is therefore necessary to play on the air passage section, but also on the duration of opening of the intake valve in order to ensure the injection of a sufficient volume of compressed air compatible with the desired use.

[0026] For comparison, with a comparable opening time, the diameter of diesel injectors is 0.1 millimeters, while the opening of the passage for compressed air is about 7 millimeters, i.e. seventy times larger.

[0027] For this reason, in the prior art, it is necessary to start the air injection before the piston has reached its top dead center.

[0028] We therefore understand that this compressed air added to the external air already compressed by the piston very strongly opposes the end of the piston's rise, which causes a loss of engine power.

[0029] A second problem is that the valve head is struck by the piston at a time when it is at a very high speed, since this happens well before the top dead center of the piston, which leads to rapid fatigue of the parts and therefore unsatisfactory reliability of the engine.

[0030] Document FR3115313 attempts to solve this second problem. In particular, it describes a modified compressed air injection valve, in which the valve is integral with the piston (no impact of the parts) and is provided with a groove of a determined length to allow the air to pass sequentially.

[0031] However, this groove must be of significant length to allow the injection of sufficient compressed air to generate the required engine work. Consequently, air begins to enter the chamber well before the piston has reached top dead center. This does not solve, or even amplifies, the first problem.

[0032] This is why it has already been proposed to add an ejection valve allowing the compressed air from the piston to escape just before injecting compressed air from the reserve into the chamber, in order to reduce the pressure in the chamber. It has also been proposed to circulate this ejected air in a volume surrounding the chamber to further heat the chamber, but this arrangement makes the engine design very complex, without bringing a notable improvement. In addition, the opening of the intake and ejection valves is controlled by two camshafts, as in thermal engines, which makes the design complex and increases friction and the weight of the assembly.

[0033] The objective of the present invention is therefore to propose an electronic solution making it possible to improve the reliability of the engine.

[0034] Another objective of the present invention is to propose a compressed air engine having lower consumption for equal generated motor power, so as to increase the autonomy and efficiency of the device equipped with said engine: vehicle or generator set.

[0035] In other words, one of the objectives of the invention is to increase the efficiency of the engine, that is to say to increase the driving power with the same quantity of injected air, or to reduce the quantity of injected air with the same driving power.

[0036] However, the inventor had the idea that an injection which would take place closer to top dead center would make it possible to reduce the negative work consumed by the piston rising.

[0037] The idea behind the invention is to propose a delayed injection of air compared to the known engine of the, making it possible to promote the rise of the piston in the last millimeters of travel up to the top dead center and to inject compressed air only when the piston is at its top dead center or as close as possible to the top dead center (before or after), while ensuring a sufficient volume of injected air to obtain a driving power compatible with the desired use. The efficiency of the engine will thus be improved.

[0038] The present invention provides an electronic type solution and allows very fine control of the air injection, thus optimizing air consumption as much as possible. The solution according to the invention, specifically adapted to the field of compressed air, also allows a significant limitation of the electrical consumption necessary for opening the valve, a problem which is specific to air injection compared to fuel injection, as will be explained later.

[0039] It allows the injection of an optimal volume of air, at an optimal position of the piston, but also a variation of the volume of air injected according to needs, in particular according to the heat of the engine, its operating speed, the conformation of the road (uphill or downhill), etc.

[0040] The principle of electronic injection is well known for a thermal engine. It consists of electronically controlling the injection according to a signal transmitted by one or more sensors and, possibly, a specific algorithm combining the information from the different sensors (temperature, position of the engine shaft, etc.) and producing a control signal adapted to the information captured.

[0041] In other words, the opening and closing of the valves are not controlled mechanically, but electrically by means of a computing unit and solenoid valves in response to one or more signals captured by sensors.

[0042] The principle of the solenoid valve, known in the field of fuel injection in thermal engines, consists of providing a valve having a rod carrying the valve head at one end, the other end being magnetic and surrounded by a coil of conductive electrical wire, preferably copper. When current flows through the coil, this moves the rod, which opens the valve, according to the principle of the electromagnet. Once the electricity is cut off, the rod returns to its initial position where the valve is closed, preferably by means of a return spring.

[0043] This principle can be adapted to compressed air. However, to allow the passage of a sufficient volume of compressed air, the valve head would have to be very large. However, the compressed air arrives above this valve head. Therefore, to lift the valve and open the passage to the compressed air, a very significant force is then required, which requires the use of very powerful electromagnets which are both expensive and consume large amounts of electricity.

[0044] Much of the mechanical work done by expanding the air on the piston will therefore be spent recharging the electric battery, so the overall efficiency would be very poor. No obvious solution has been proposed to date.

[0045] An additional objective of the present invention is therefore to propose an electronic injection mechanism consuming little electrical energy and being inexpensive.

[0046] Another objective is to provide a more homogeneous electronic injection system in the piston chamber.

[0047] Indeed, when compressed air is injected through a point valve, its distribution is not homogeneous and the expansion of the air can create zones of different stresses on the piston, increasing piston fatigue over time.

[0048] The idea behind the invention is to pivot the valve stem and the valve head at right angles to the opening direction in the cylinder head, so that, with the stem being perpendicular to the direction of the compressed air pressure, moving the stem and opening the compressed air passage requires almost no mechanical work and very little energy (electrical or pneumatic).

[0049] An engine covered by the invention is similar to that illustrated in, but is distinguished therefrom by the particular design of the valve and the cylinder head.

[0050] Thus, the invention relates to a compressed air injection device designed to equip a compressed air engine comprising at least one piston intended to move in a chamber and a cylinder head internally traversed by at least one intake passage substantially parallel to the direction of injection of the compressed air into the chamber of the piston and by at least one channel perpendicular and transverse to said passage, said device comprising at least one compressed air intake valve, each valve being adapted to operate with a piston of the engine when the device is in the position of use in the engine and comprising: - a bar arranged to slide in said channel, said bar comprising a first part provided with at least one intake orifice, and a second position control part, the valve further comprising: - a means for returning the bar and, - on either side of the second position control part,one or more actuators (electromagnets or pneumatic actuators) connected to a power source (electric or pneumatic) controllable by a control unit, the latter being connected to at least one piston position sensor, the control unit being programmed to control the power supply (electric or pneumatic) of the actuator(s) (electromagnets or pneumatic actuators) and to move, in operation, the bar into a position between an open position of said at least one intake passage in which said at least one intake orifice carried by the first part is entirely aligned with said at least one passage, and a closed position in which the intake orifice carried by the first part is entirely offset relative to said at least one passage.,

[0051] The invention also relates to a compressed air engine cylinder head provided with an injection device according to the invention, the cylinder head being internally traversed by at least one intake passage substantially parallel to the direction of injection of the compressed air into the piston chamber and by a channel perpendicular and transverse to said at least one passage.

[0052] In a variant of this device, the cylinder head is also internally traversed by a compressed air discharge / charge duct comprising at least one discharge / charge passage traversed perpendicularly and transversely by a channel arranged next to the channel receiving the intake valve, the device further comprising a discharge / charge valve arranged next to the intake valve, and comprising:- a bar arranged slidably in said at least one channel, said bar comprising a first part provided with at least one discharge / charge orifice, and a second position control part, the valve further comprising:- a means for returning the bar and,- on either side of the second position control part, at least one actuator connected to an energy source controllable by a control unit, the latter being connected to at least one piston position sensor,the control unit being programmed to control an energy supply to the actuator from the energy source and to move, in operation, the bar into a position between an open position of said at least one discharge / charge passage in which said at least one discharge / charge orifice carried by the first part is entirely aligned with said at least one discharge / charge passage, and a closed position of said at least one discharge / charge passage of the intake valve in which said at least one discharge / charge orifice carried by the first part is entirely offset from said at least one discharge / charge passage.,

[0053] The invention also relates to a compressed air engine cylinder head provided with an injection device according to the invention, furthermore internally traversed by at least one discharge / charge passage substantially parallel to the direction of injection of the compressed air into the piston chamber and by a channel perpendicular and transverse to said passage.

[0054] In a preferred embodiment, the injection device is intended for a compressed air engine whose cylinder head has several intake passages, distributed homogeneously relative to the width of the piston chamber.

[0055] In this case, the cylinder head is internally traversed by a plurality of intake passages of determined opening section and substantially parallel to the direction of injection of the compressed air into the piston chamber, the intake passages being spaced apart by a determined distance greater than or equal to the opening section of the intake passages and by at least one channel perpendicular and transverse to all the intake passages, the device comprising at least one compressed air intake valve, each valve being adapted to operate with a piston of the engine when the device is in the position of use in the engine and comprising a bar arranged in a sliding manner in said channel, said bar comprising a first part provided with as many intake orifices as the cylinder head comprises compressed air intake passages, the intake orifices being spaced apart by the same distance as the intake passages in the intake duct,and a second position control part, the valve further comprising a means for returning the bar and, on either side of the second control part, actuators connected to a power source controllable by a control unit, the latter being connected to at least one piston position sensor, the control unit being programmed to control the electrical supply of the actuators (electromagnets or pneumatic actuators) and move the bar into a position between an open position of the intake passages in which the intake orifices carried by the first part are entirely aligned with the intake passages, and a closed position in which the intake orifices carried by the first part are entirely offset from the intake passages.,

[0056] Thanks to the perpendicular arrangement of the or each bar relative to the direction of the compressed air intake passages, the mechanical work required to move the bar is negligible, or even zero.

[0057] The invention therefore allows electronically controlled injection of compressed air, with very low electrical consumption or very low consumption of auxiliary compressed air (i.e. not participating in the movement of the piston, but used to activate the pneumatic actuators).

[0058] Furthermore, in the embodiment where the cylinder head comprises several intake passages distributed homogeneously over the upper surface of the piston chamber, the control of the bar provided with several intake orifices allows the perfectly simultaneous opening of the intake orifices and therefore a homogeneous injection of compressed air into the piston chamber.

[0059] Furthermore, it is possible to control the opening of the intake passage(s) when the piston is at its top dead center, or even just after top dead center, so that the engine develops maximum power.

[0060] In a variant of this device, the cylinder head is also internally traversed by a compressed air discharge / charge duct comprising at least one discharge / charge passage traversed perpendicularly and transversely by the channel, and in which the first part of the bar further comprises at least one discharge / charge orifice intended to align, in operation, with said at least one discharge / charge passage of the discharge / charge duct, the intake orifices and the discharge / charge orifices being arranged on the first part of the bar such that in operation, when the bar is moved by the control unit into a position between: - the opening position of the intake passage, in which said at least one intake orifice carried by the first part of the bar is entirely aligned with said at least one intake orifice (110, 111),while said at least one discharge / charge orifice carried by the first part of the bar is entirely offset from said at least one discharge / charge passage;- the "closed" position of said at least one intake passage and said at least one discharge / charge passage, in which said at least one intake orifice carried by the first part of the bar is entirely offset from said at least one intake passage, and said at least one discharge / charge orifice carried by the first part of the bar is entirely offset from said at least one discharge / charge passage; and- a compressed air discharge / charge position in which said at least one intake passage is closed and said at least one discharge / charge passage is open, said at least one intake orifice carried by the first part of the bar being entirely offset from said at least one intake passage,and said at least one discharge / charge orifice carried by the first part of the bar being entirely aligned with respect to said at least one discharge / charge passage; the closed position being intermediate, in the movement of the bar, between the open position and the discharge / charge position.,

[0061] In another embodiment, the valve comprises another bar arranged slidably in said at least one channel, this other bar comprising a first part comprising as many intake ports as the cylinder head comprises compressed air intake passages, the intake ports being spaced the same distance apart as the intake passages, and a second position control part, the two bars being arranged head to tail, the valve further comprising a means for returning the other bar and, on either side of the second position control part, actuators (electromagnets or pneumatic actuators) connected to a source of energy (electric or pneumatic) controllable by said control unit,the control unit being programmed to control the power supply (electric or pneumatic) of the actuators (electromagnets or pneumatic actuators) and to move the other bar between an open position of the intake passages in which the intake orifices carried by the other bar are entirely aligned with the intake passages, and a closed position in which the intake orifices carried by the other bar are entirely offset from the intake passages.,

[0062] In a variant of this device, the cylinder head is also internally traversed by a compressed air discharge / charge duct comprising at least one discharge / charge passage traversed perpendicularly and transversely by the channel, and in which the first part of each bar further comprises as many discharge / charge orifices as the discharge / charge duct comprises discharge / charge passages, the intake orifices and the discharge / charge orifices being arranged on the first part of each bar, such that in operation, the control unit is programmed to control the energy supply of the actuators from the energy source and move each bar between two operating positions: - A simultaneous position (PSO) for opening the intake passage and closing the discharge / charge passage,wherein each intake orifice carried by the first part of each bar is fully aligned with said at least one corresponding intake passage, while each discharge / charge orifice carried by the first part of each bar is fully offset from said at least one corresponding discharge / charge passage; and- A simultaneous position (PSF) of closing said at least one intake passage and opening said at least one discharge / charge passage, wherein each intake orifice carried by the first part of each bar is fully offset from said at least one corresponding intake passage, and each discharge / charge orifice carried by the first part (21) of each bar is fully aligned with said at least one corresponding discharge / charge passage.,

[0063] In a preferred embodiment, the second position control part of the or each bar is magnetic, and the actuator(s) are electromagnets, the energy source being an electrical source.

[0064] In another advantageous embodiment, the actuator(s) are pneumatic actuators, and the power source is a pneumatic source of compressed air, preferably the high-pressure compressed air supply via an auxiliary circuit leading compressed air to the pneumatic actuators independently of the injection of compressed air into the piston chamber.

[0065] The invention also relates to a compressed air engine cylinder head provided with an injection device according to the invention, the cylinder head being internally traversed by a plurality of intake passages of determined opening section and substantially parallel to the direction of injection of the compressed air into the piston chamber, the intake passages being spaced apart by a determined distance greater than or equal to the opening section of the intake passages and by a channel perpendicular and transverse to all the intake passages.

[0066] The same configuration can be used for the exhaust on a four-stroke engine cylinder.

[0067] The invention also relates to a compressed air engine cylinder head provided with an injection device according to the invention, furthermore internally traversed by a plurality of discharge / charge passages of determined opening section, and substantially parallel to the direction of injection of the compressed air into the piston chamber, the discharge / charge passages being spaced apart by a determined distance (D1) greater than or equal to the opening section of the intake passages, and by at least one channel perpendicular and transverse to all the intake passages.

[0068] The invention also relates to a compressed air engine cylinder head provided with an injection device according to the invention, furthermore internally traversed by a plurality of discharge / charge passages with an opening section identical to the opening section of the intake passages, and substantially parallel to the direction of injection of the compressed air into the piston chamber, the intake passages and the discharge / charge passages being spaced apart by a determined distance (D1) greater than or equal to twice the opening section of the intake passages.

[0069] The invention also relates to a compressed air engine incorporating a cylinder head according to the invention.

[0070] The invention also relates to a hybrid powertrain intended to equip a vehicle comprising a high-pressure compressed air reservoir connected to a compressed air piston engine according to the invention engaged with an electric generator to generate electricity when it is driven by the compressed air piston engine, the electric generator being connected to at least one electric motor itself connected to a transmission engaged with a vehicle movement member.

[0071] Preferably, the generator and said at least one electric motor are connected via a relay electrical reserve with a capacity of between 0.2 and 2.2 Watt-hours per kilo of vehicle to be equipped (Wh / kg of vehicle).

[0072] Preferably, the drive chain further comprises an accelerator control movable between a stop position and a maximum acceleration position and connected to an electronic control circuit comprising a controller programmed to power the electric motor from the relay electrical reserve as a function of a signal captured by at least one sensor fitted to the vehicle.

[0073] The invention relates to a generator set comprising or intended to be associated with a high-pressure compressed air tank. The generator set comprises a compressed air piston engine according to the invention engaged with an electric generator to generate electricity when driven by the compressed air piston engine.

[0074] The invention finally relates to a method for managing air in a powertrain provided with a main compressed air reservoir and a compressed air engine comprising:– an engine block comprising N cylinders, N being an integer greater than or equal to 1, the or each cylinder having a chamber and a piston mounted movable in translation in said chamber between a high position called “top dead center” and a low position called “bottom dead center”, the chamber comprising an exhaust outlet; and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head comprising, for each chamber at least one compressed air intake valve, and a discharge / charge valve;the method being characterized in that it comprises the following successive steps, for each cylinder:1) Compression by the piston of the air present in the chamber;2) Discharge of the compressed air from the chamber to a buffer reserve through the discharge / charge valve;3) Admission of compressed air into the piston chamber from the main reservoir through the inlet valve;4) Charging of the air stored in the buffer reserve to the piston chamber through the discharge / charge valve;5) Exhaust of the expanded air from the piston chamber to the outside through the exhaust outlet.;

[0075] Thus, the invention relates to a compressed air engine comprising:– an engine block comprising at least one cylinder having a chamber and a piston, said piston being mounted movable in translation in said chamber, and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head being internally traversed by at least one intake passage substantially parallel to the direction of injection of the compressed air into the chamber of the piston and by a channel perpendicular and transverse to said at least one passage, and comprising an electronic device for injecting compressed air, said device comprising at least one compressed air intake valve, each valve being adapted to operate with a piston of the engine when the device is in the position of use in the engine and comprising:- a bar arranged in a sliding manner in said channel, said bar comprising a first part provided with at least one orifice,and a second position control part, the valve further comprising,- a means for returning the bar and,- on either side of the second position control part, at least one actuator connected to a power source controllable by a control unit, the latter being connected to at least one piston position sensor, the control unit being programmed to control an energy supply to the actuator from the power source and to move, in operation, the bar into a position between an open position of said at least one intake passage in which said at least one intake orifice carried by the first part is entirely aligned with said at least one passage, and a closed position in which said at least one intake orifice carried by the first part is entirely offset relative to said at least one passage.,

[0076] In a preferred embodiment, the compressed air engine comprises a cylinder head having a plurality of intake passages, distributed homogeneously with respect to the width of the piston chamber.

[0077] Thus, the invention also relates to a compressed air engine comprising:– an engine block comprising at least one cylinder having a chamber and a piston, said piston being mounted movable in translation in said chamber, and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head being traversed internally by a plurality of intake passages of determined opening section and substantially parallel to the direction of injection of the compressed air into the piston chamber, the intake passages being spaced apart by a determined distance greater than or equal to the opening section of the intake passages and by a channel perpendicular and transverse to all the intake passages, the cylinder head comprising an electronic device for injecting compressed air, said device comprising at least one compressed air intake valve,each valve being adapted to operate with a piston of the engine when the device is in the position of use in the engine and comprising a bar arranged in a sliding manner in said channel, said bar comprising a first part provided with as many intake ports as the cylinder head has compressed air intake passages, the intake ports being spaced the same distance apart as the intake passages, and a second position control part, the valve further comprising a means for returning the bar and, on either side of the second control part, actuators connected to a power source controllable by a control unit, the latter being connected to at least one piston position sensor,the control unit being programmed to control the electrical supply of the actuators (electromagnets or pneumatic actuators) and move the bar into a position between an open position of the intake passages in which the intake orifices carried by the first part are entirely aligned with the intake passages, and a closed position in which the intake orifices carried by the first part are entirely offset from the intake passages.,

[0078] In another embodiment of the engine, the valve comprises another bar arranged slidably in said channel, this other bar comprising a first part comprising as many intake ports as the cylinder head comprises compressed air intake passages, the intake ports being spaced the same distance apart as the intake passages, and a second position control part, the two bars being arranged head to tail, the valve further comprising a means for returning the other bar and, on either side of the second position control part, actuators (electromagnets or pneumatic actuators) connected to a source of energy (electric or pneumatic) controllable by said control unit,the control unit being programmed to control the power supply (electric or pneumatic) of the actuators (electromagnets or pneumatic actuators) and to move the other bar between an open position of the intake passages in which the intake orifices carried by the other bar are entirely aligned with the intake passages, and a closed position in which the intake orifices carried by the other bar are entirely offset from the intake passages.,

[0079] In particular and / or advantageous embodiments, one or other of these motors may comprise one and / or other of the following characteristics: The second position control part of the or each bar is magnetic, and the actuator(s) are electromagnets, the energy source being an electrical source.

[0080] Alternatively, the actuator(s) may be pneumatic actuators.

[0081] Thus, the invention also relates to a cylinder head intended to equip a compressed air engine according to the invention, provided with an injection device according to the invention, the cylinder head being internally traversed by at least one intake passage substantially parallel to the direction of injection of the compressed air into the piston chamber and by at least one channel perpendicular and transverse to said at least one passage.

[0082] The invention also relates to a cylinder head intended to equip a compressed air engine according to the invention, provided with an injection device according to the invention, the cylinder head being internally traversed by a plurality of intake passages of determined opening section and substantially parallel to the direction of injection of the compressed air into the piston chamber, the intake passages being spaced apart by a determined distance greater than or equal to the opening section of the intake passages and by at least one channel perpendicular and transverse to all the intake passages.

[0083] The invention also relates to a cylinder head intended to equip a compressed air engine according to the invention, provided with an injection device according to the invention and traversed, in addition, internally by at least one discharge / charge passage substantially parallel to the direction of injection of the compressed air into the piston chamber and by a channel perpendicular and transverse to said passage.

[0084] The invention also relates to a cylinder head intended to equip a compressed air engine according to the invention, provided with an injection device according to the invention and traversed, in addition, internally by a plurality of discharge / charge passages of determined opening section, and substantially parallel to the direction of injection of the compressed air into the piston chamber, the discharge / charge passages being spaced apart by a determined distance (D1) greater than or equal to the opening section of the intake passages, and by at least one channel perpendicular and transverse to all the intake passages.

[0085] The invention also relates to a compressed air engine cylinder head provided with an injection device according to the invention, provided with an injection device according to the invention and traversed, in addition, internally by a plurality of discharge / charge passages with an opening section identical to the opening section of the intake passages, and substantially parallel to the direction of injection of the compressed air into the piston chamber, the intake passages and the discharge / charge passages being spaced apart by a determined distance (D1) greater than or equal to twice the opening section of the intake passages.

[0086] The invention also relates to an electronic injection device intended to equip a compressed air engine and / or a cylinder head according to the invention, this device comprising the characteristics previously described.

[0087] The invention will be better understood and other aims, advantages and characteristics thereof will appear more clearly on reading the description which follows and which is made with reference to the appended drawings, in which:

[0088] is a sectional view of a conventional two-stroke air-powered engine which has been previously described;

[0089] represents, in figure 2a, a sectional view of a first embodiment of an injection device according to the invention, the device being in the closed position, and, correspondingly in figure 2b, a top view of the bar of the device in its closed position;

[0090] represents, in figure 3a, a sectional view of the first embodiment of an injection device according to the invention of figure 2a, in the open position, and, correspondingly in figure 3b, a top view of the bar of the device in its open position;

[0091] is a sectional view of a second embodiment of an injection device according to the invention, the device being in the closed position;

[0092] is a sectional view of the second embodiment of an injection device according to the invention, the device being in the open position;

[0093] is a sectional view of the second embodiment of an injection device according to the invention, the device being in the partially open position;

[0094] is a Clapeyron diagram of a conventional compressed air engine, shown in; and

[0095] is a Clapeyron diagram of a compressed air engine according to the invention, illustrated in.

[0096] represents, in figure 9a, a sectional view of a variant of the first embodiment of an injection device according to the invention, the device being in the open position, and, correspondingly in figure 9b, a top view of the bar of the device in its closed position;

[0097] represents, in figure 10a, a sectional view of the variant of the first embodiment of an injection device according to the invention illustrated in, the device being in the closed position, and, correspondingly in figure 10b, a top view of the bar of the device in its closed position;

[0098] represents, in figure 11a, a sectional view of a first mode of implementation of the air management method according to the invention, in the discharge / charge phase, the discharge / discharge passages being open and the intake passages being closed; correspondingly in figure 11b, a top view of the bar and correspondingly in figure 11c, a polar diagram illustrating the position of the cylinder in the PHD sector;

[0099] represents, in figure 12a, a sectional view of a first mode of implementation of the air management method according to the invention, in the closed position of the discharge / discharge passages and the intake passages; in correspondence in figure 12b, a top view of the bar and in correspondence in figure 12c, a polar diagram illustrating the position of the cylinder between the PHD sector and the PHI sector;

[0100] represents, in figure 13a, a sectional view of a first mode of implementation of the air management method according to the invention, in the open position of the intake passages and the closed position of the discharge / discharge passages; in correspondence in figure 13b, a top view of the bar and in correspondence in figure 13c, a polar diagram illustrating the position of the cylinder in the PHI sector;

[0101] represents, in figure 14a, a sectional view of a first mode of implementation of the air management method according to the invention, in the closed position of the discharge / discharge passages and the intake passages; in correspondence in figure 14b, a top view of the bar and in correspondence in figure 14c, a polar diagram illustrating the position of the cylinder between the PHI sector and the PHC sector;

[0102] represents, in figure 15a, a sectional view of a first mode of implementation of the air management method according to the invention, in the charging phase, the discharge / discharge passages being open and the intake passages being closed; correspondingly in figure 15b, a top view of the bar and correspondingly in figure 15c, a polar diagram illustrating the position of the cylinder in the PHC sector;

[0103] represents, in figure 16a, a sectional view of a first mode of implementation of the air management method according to the invention, in the closed position of the discharge / discharge passages and the intake passages; in correspondence in figure 16b, a top view of the bar and in correspondence in figure 16c, a polar diagram illustrating the position of the cylinder in the PHE sector;

[0104] represents a sectional view of a second mode of implementation of the air management method according to the invention;

[0105] represents a sectional view of a third embodiment of the air management method according to the invention, in the discharge phase, the discharge / discharge passages being open and the intake passages being closed;

[0106] represents a sectional view of a third embodiment of the air management method according to the invention, in the closed position of the discharge / discharge passages and the intake passages;

[0107] represents a sectional view of a third embodiment of the air management method according to the invention, in the position of opening the intake passages and closing the discharge / discharge passages;

[0108] represents a sectional view of a third embodiment of the air management method according to the invention, in the closed position of the discharge / discharge passages and the intake passages;

[0109] represents a sectional view of a third embodiment of the air management method according to the invention, in the charging phase, the discharge / discharge passages being open and the intake passages being closed; and

[0110] represents a sectional view of a third embodiment of the air management method according to the invention, in the closed position of the discharge / discharge passages and the intake passages.

[0111] Elements common to the different figures are designated by the same references.

[0112] The first embodiment illustrated in Figures 2 and 3 will now be described.

[0113] Figure 2a shows a compressed air engine with the injection device in the closed position, while the piston 1 is between top dead center and bottom dead center, and Figure 3a shows the same engine with the injection device in the open position, while the piston 1 is at top dead center (TDC). Reference A designates the engine's cylinder block, reference B its cylinder head, and reference 5 the compression / extension chamber in which the piston 1 is mounted in translation.

[0114] The cylinder head B is pierced to provide a compressed air intake duct 11 which communicates with a high-pressure compressed air reserve (not shown) and with a plurality of intake passages which open into the chamber 5 of the piston 1. Figures 2a and 3a illustrate five intake passages 110 to 114, but the invention can be implemented with at least one passage.

[0115] These intake passages 110 to 114 extend substantially parallel to the direction of injection of the compressed air into the chamber 5. In the example illustrated in the figures, this injection direction corresponds to the direction of movement of the piston.

[0116] Each of these intake passages has a determined opening section S1 and two adjacent intake passages are spaced apart by a determined distance D1 which is equal to or preferably greater than the opening section of the intake passages. In the example illustrated in the figures, the section S1 is the same for all the intake passages, but the invention is not limited to this embodiment.

[0117] The cylinder head B is also internally crossed by a channel 13 which extends transversely to all the intake passages 110 to 114 and which is therefore substantially perpendicular to the direction of movement of the piston (arrow F6).

[0118] The valve S comprises a straight, elongated member or bar 20 slidably mounted in the channel 13 and comprising a first portion 21 which passes through the channel 13 and a second portion 22 for controlling the position of the bar in the channel 13.

[0119] Figures 2 and 3 show that a sealing device 14, such as a gasket, is advantageously provided in the channel 13 around the first part 21, over at least part of its length to ensure sealing and prevent the passage of compressed air around the bar. In other words, the air can only pass through the inlet orifice(s) carried by the bar.

[0120] Thus, the first part 21 has the general shape of a blade which is pierced with five intake orifices 210 to 214. Generally, the number of intake orifices is equal to the number of intake passages 110 to 114 provided in the cylinder head B.

[0121] Furthermore, two adjacent intake ports are spaced by the same distance D1 which separates two adjacent intake passages of the cylinder head and each intake port has an opening section S1, identical to that of the intake passages made in the cylinder head B, but the invention is not limited to this embodiment. What matters, as described below, is that the movement of the bar relative to the intake passages provided in the cylinder head B allows a position of the bar between (i.e. including) an open position in which the intake ports 210, 211, 212, 213, 214 of the bar are fully aligned with the intake passages 110, 111, 112, 113, 114 of the cylinder head, and a closed position in which the intake ports 210, 211, 212, 213, 214 of the bar are fully offset from the intake passages 110, 111, 112, 113, 114 of the cylinder head.

[0122] The second part 22 comprises a part 220 connected on the one hand to the first part 21 and on the other hand to a rod 221. The section of the part 220 is greater than that of the first part 21 and that of the rod 221.

[0123] Around the rod 221, and against the part 220, is mounted a return spring 40.

[0124] This second part 22 is mounted in a chamber 31 formed inside a block 30, placed on one side of the cylinder head B or integrated into the cylinder head, laterally with respect to the intake passages 110, 111, 112, 113, 114.

[0125] This chamber 31 comprises a first chamber 310 whose section is substantially equal (i.e. immediately greater) than that of the part 220, so as to ensure its guidance when this second part slides in the first chamber 310. On the side of the cylinder head B, this first chamber 310 comprises a bottom 312. It also comprises a second chamber 311 whose section is greater than that of the spring 40 and less than that of the first chamber 310.

[0126] Thus, a shoulder 313 is formed between the two chambers to limit the movement of the second part 22 in the chamber 31.

[0127] On either side of the second part 22, at least one actuator 50 is arranged, fixed on or in the block 30.

[0128] In the embodiment illustrated and described below, the actuators are electromagnets 50. In this case, the second position control part 22 is magnetic. This or these electromagnets 50 are connected to an electrical source controllable by a control unit (not shown in the figures).

[0129] This control unit is also connected to at least one piston position sensor (not shown in the figures) and is programmed to control the electrical supply to the electromagnets and move the bar between a closed position shown in figures 2a and 2b and an open position shown in figures 3a and 3b.

[0130] The operation of the injection device will now be described more precisely for an example with electromagnets 50.

[0131] Thus, in Figures 2a and 2b, the start of the engine operating cycle is illustrated, while valve S is in the closed position and piston 1 rises in chamber 5 (arrow F6). The ambient air contained in chamber 5 is then compressed and rises in temperature.

[0132] In this closed position, the electromagnet is not activated by the electrical source and the part 220 is pushed against the wall 312 by the return spring 40.

[0133] As more precisely illustrated, in this position, the intake orifices 210 to 214 provided in the first part 21 of the bar 20 are not opposite the intake passages 110 to 114 provided in the cylinder head, that is to say that they are entirely offset from the intake passages 110 to 114 provided in the cylinder head. As a result, the bar 20 (and the seal 14) prevent any arrival of compressed air in the chamber 5.

[0134] Figure 3a illustrates piston 1 at its top dead center (TDC), a position detected by the control unit, using the piston position sensor.

[0135] The control unit then controls the electrical source so that it supplies the electromagnets 50. This causes the bar 20 to move, this translational movement leading the second part 22 of the bar to move away from the yoke B, until the part 220 comes into abutment on the shoulder 313.

[0136] As more precisely illustrated, in this open position, the intake ports 210 to 214 provided in the first part 21 of the bar 20 are entirely opposite the intake passages 110 to 114 (see figure 3b). As a result, the bar 20 allows the arrival of compressed air in the chamber 5.

[0137] The air in chamber 5 expands, pushing piston 1 downwards.

[0138] Once the required volume of compressed air has been injected, the control unit then controls the electrical source so that it stops supplying power to the electromagnet(s) 50. This causes the bar 20 to move, this translational movement causing the second part 22 of the bar to move closer to the cylinder head B, until the part 220 comes into abutment on the bottom 312 of the first chamber 310.

[0139] The valve S is then again in the closed position shown in Figure 2a and any air intake is prevented.

[0140] The closing command can be made by calculating the volume of compressed air injected and / or by detecting the position of the piston during its descent.

[0141] The downward translational movement of the piston continues until it reaches its bottom dead center.

[0142] Piston 1 can then rise for a new cycle.

[0143] The foregoing description shows that the first portion 21 of the bar acts as a shutter by cooperating with the intake passages 110 to 114 to close or open them and is therefore, from a functional point of view, similar to a valve head.

[0144] Furthermore, the second part 22 of the bar ensures its guidance and is, from a functional point of view, similar to a valve stem.

[0145] The injection device which has just been described comprises a plurality of intake passages for the compressed air in the cylinder head B and a plurality of intake orifices in the bar 20. The invention is however not limited to this embodiment and the cylinder head B could comprise only a single intake passage 10 for the compressed air opening into the piston chamber and a single intake orifice 10 in the first part of the bar.

[0146] This embodiment makes it possible to take advantage of the structure of the valve stem and head and their arrangement perpendicular to the direction of movement of the piston and to the direction of injection of the compressed air into the piston chamber (therefore the direction of the intake passages in the cylinder head), in order to distribute the volume of compressed air injected into the piston chamber by adjusting the position of the bar 20 relative to the channel 13.

[0147] A second embodiment is illustrated in. The valve S' comprises a bar 20, associated with a return spring 40, a block 30 in which the second part 22 of the bar slides, and electromagnets 50, as has been described in detail with regard to figures 2a to 3b. It also comprises these same parts arranged opposite each other on the other side of the cylinder head. The latter has the same structure as the cylinder head illustrated in figures 2a and 3a.

[0148] In other words, the valve S' comprises another bar 20a identical to the bar 20, associated with a return spring 40a, a block 30a in which the second part 22a of the bar slides, and electromagnets 50a. The intake orifices 210a, 211a, 212a, 213a, 214a made in this bar 20a therefore have an opening section S1 and are spaced by the same distance D1 which separates two adjacent intake passages of the cylinder head.

[0149] The two bars 20 and 20a are arranged head to tail, so that their first parts 21 and 21a pierced with inlet orifices are parallel and slide inside the channel 13 formed in the cylinder head. The size of this channel is modified accordingly. Alternatively, it is possible to provide another channel parallel to the channel 13 and receiving the bar 20a.

[0150] As previously, the electromagnet(s) 50 and 50a are connected to the electrical source controllable by the control unit (not shown in the figures).

[0151] This control unit is programmed to independently control the power supply to the electromagnets and independently move each bar to a position between (i.e. including) a closed position and an open position.

[0152] Thus, by combining two bars 20 and 20a oriented head to tail and parallel, and by controlling them independently, that is to say differentially, it is possible to move one a little more than the other and, consequently, to modulate the section of the openings resulting from the superposition of the intake orifices of each bar.

[0153] In other words, as illustrated in, when the electromagnets 60 and 60a are not activated by the electrical source, the parts 220 and 220a are pushed against the bottoms 312 and 312a of the first chambers 310, 310a by the return spring 40, 40a.

[0154] In this position, the two bars 20, 20a are arranged so that their intake orifices provided in the first part 21, 21a of each bar coincide without being opposite the intake passages 110 to 114 provided in the cylinder head. As a result, the bars 20 and 20a prevent any passage of compressed air into the chamber 5 and the valve S' is in the closed position. It is understood that it is sufficient for only one of the bars to be in the closed position to prevent any passage of air.

[0155] Lamontre shows that by simultaneously and identically controlling the movement of the two bars 20 and 20a, the inlet ports of each bar align completely and perfectly and offer a maximum opening section for the compressed air. The valve S' is therefore in the fully open position.

[0156] Alternatively, as illustrated in, by simultaneously controlling, but in different ways, the movement of the two bars 20 and 20a, the intake ports of each bar are offset (the axes of the intake ports of the first bar, in dashed-dots, are offset from the axes of the intake ports of the second bar, in dotted lines). Thus, the section of the opening, resulting from the offset superposition of the intake ports of the two bars, is smaller than the section of the intake ports. The volume of compressed air injected into the piston chamber can thus be modulated, for example as a function of the engine temperature, its operating speed, the required acceleration, the slope of the road requiring a temporary power surplus, etc.

[0157] As a corollary, the differential control of the two bars allows an opening / closing reaction of the intake passages twice as fast as with a single bar, since the two bars are actuated in the same direction, but in opposite directions, so that each intake passage is closed when each bar is moved by a distance equal to half the diameter of each orifice, whereas in a device with a single bar, each intake passage is closed when the bar is moved by a distance equal to the diameter of each orifice.

[0158] The air injection is therefore much more precise, so that the engine's consumption is reduced while providing maximum power thanks to a homogeneous injection of compressed air, and at the moment when the piston is in an optimized position, that is to say at its top dead center, slightly before or slightly after.

[0159] Furthermore, since the mechanical work required to move the or each bar is negligible or even zero, the electrical consumption of the injection device according to the invention is very low. Almost all of the driving power generated can therefore be devoted to the vehicle's drive or to the driving action, without it being necessary to divert a large part of it to generate electricity intended to power the electronic injectors.

[0160] It is also possible to replace, in the examples given, the electromagnets with pneumatic actuators. In this case, they are supplied with compressed air from the compressed air reserve via an auxiliary network comprising a pressure reducer and valves controllable by the control unit. The second position control part 22 is then connected to the pneumatic actuator which will control the movement of the bar 20-20a.

[0161] This variant is illustrated in Figures 9 and 10 which will now be described.

[0162] Figure 9a shows a compressed air engine with the injection device in the open position and therefore corresponds to Figure 3a, to the description of which reference may be made.

[0163] Similarly, Figure 10a represents this same engine with the injection device in the closed position and therefore corresponds to Figure 2a, the description of which can also be referred to.

[0164] In this variant, the electromagnets 50 present on the motors shown in Figures 2a and 3a are removed. On the other hand, a solenoid valve V is provided which is in fluid communication with the chamber 31 provided in the block 30, thanks to a conduit C1. This solenoid valve is also in fluid communication with a compressed air tank V, thanks to a conduit C2.

[0165] The spring 40 is calibrated to the pressure of the compressed air present in the reservoir R so as to ensure that the blade or first part 21 is held in the open position or in the closed position. Figures 9 and 10 illustrate the situation in which the spring 40 is calibrated to ensure that the blade is held in the open position.

[0166] Thus, to move the blade 21 from the open position illustrated in to the closed position illustrated in, the solenoid valve is actuated to pass the air from the reservoir R into the first chamber 310 and thus push the part 220 of the second part 22 towards the bottom 314 of the second chamber 311.

[0167] Similarly, to move the blade 21 from the closed position illustrated in to the open position illustrated in, the solenoid valve V is actuated to ensure the escape of the air present in the first chamber 310 to an air recovery circuit C3.

[0168] Of course, the operation will be reversed if the spring 40 is calibrated to ensure that the blade is held in the closed position.

[0169] Furthermore, pneumatic actuators can also be provided for the valve illustrated in Figures 4 to 6 and which has two bars.

[0170] The use of pneumatic actuators is also very energy-efficient thanks to the availability of medium-pressure air.

[0171] Generally speaking, the various embodiments of the invention make it possible to generate mechanical work similar to the known device of the, but with a much smaller quantity of air, and at a lower exhaust pressure, thus limiting engine fatigue.

[0172] Thus, figures 7 and 8 illustrate the Clapeyron diagrams of a conventional device and of a device according to the invention.

[0173] More precisely, the illustrates the Clapeyron diagram of a classic piston engine, shown in. In this figure as in the, the Volume variable, classically used in a Clapeyron diagram, is replaced by the Height of the chamber between the cylinder head and the piston, since the section of the piston chamber is constant.

[0174] This diagram reads as follows:

[0175] At point 1, the piston is in the bottom position (BDC), so the chamber height is at its maximum. Outside air is admitted into the chamber at atmospheric pressure.

[0176] As the piston moves up, the height of the chamber decreases and the pressure of the air inside the chamber increases to reach point 2.

[0177] At this height, the piston meets the valve head, lifts it, and opens the valve. The injection of compressed air immediately increases the pressure to reach point 3. The piston continues to rise to top dead center, against the air pressure, so that the system consumes work from point 3 to point 3*. Then the piston begins to descend again, until the valve closes (passing from point 3* to point 3), generating work that compensates for the work consumed by the piston to reach its top dead center (passing from point 3 to point 3*). This compensation of work consumed / work created is symbolized in the figure by a horizontal line between point 3 and point 3* which illustrates zero work.

[0178] From point 3, the compressed air continues to expand, pushing back the piston and generating work (area under the curve corresponding to the integral of the curve P=f(H)). The height of the chamber therefore increases again and the pressure inside the chamber drops until the air escapes, at point 4, through the exhaust outlet 12 of the chamber (see).

[0179] The pressure therefore immediately decreases to atmospheric pressure (point 5). The piston drops further to its bottom dead center (point 1 of the diagram), allowing the admission of outside air for a new cycle towards point 2.

[0180] Illustrates the Clapeyron diagram of an electronic injection engine according to the invention (in solid line), illustrated in. This diagram reads as follows:

[0181] At point 1a, the piston is in the bottom position (BDC), so the chamber height is at its maximum. Outside air is admitted into the chamber at atmospheric pressure.

[0182] As the piston moves up, the height of the chamber decreases and the pressure of the air inside the chamber increases to reach point 2.

[0183] At this height, the piston is at its top dead center and the valve is opened by the control unit which receives the piston position information from a sensor. The injection of compressed air immediately increases the pressure to reach point 3a.

[0184] Then the piston begins to descend again and the valve closes after an optimal volume of compressed air has been injected. From point 3a, the compressed air expands, pushing the piston back and generating work. The height of the chamber therefore increases again and the pressure inside the chamber drops until the air escapes, at point 4a, through the chamber's exhaust outlet (identical to outlet 12 of the).

[0185] The pressure therefore immediately decreases to atmospheric pressure (point 5a). The piston drops further to its bottom dead center (point 1 of the diagram), allowing the admission of outside air for a new cycle towards point 2.

[0186] The Clapeyron diagram of the classic engine is shown on the dotted line to illustrate the difference in work between the classic injection system and the injection system according to the invention.

[0187] In this figure, the white area W3 represents the work identical to both devices. The dotted area W2 represents the specific work of a device according to the invention of the, and the hatched area W1 represents the specific work of a conventional device of the.

[0188] In the case of an electronic injection system according to the invention, it is noted that the work generated W2 is comparable to the work generated by a conventional device.

[0189] If the resulting power is therefore similar, the air consumption of a device according to the invention is much lower than a conventional device. In addition, at a given piston height Hx, the expansion pressure Pxi is lower with a device according to the invention than the pressure Pxc with a conventional device, so that engine wear is less. The engine according to the invention is therefore more reliable.

[0190] Furthermore, thanks to delayed injection, it is possible to inject compressed air at a low pressure from 15 bars (compared to at least 30 in the standard engine of the), which limits the fatigue of the parts.

[0191] The whole process and device can be used for exhaust in a conventional cylinder.

[0192] A particularly interesting application of the engine according to the invention is to integrate it into a hybrid powertrain intended to equip a vehicle comprising a high-pressure compressed air tank connected to a compressed air piston engine according to the invention engaged with an electric generator to generate electricity when it is driven by the air piston engine.

[0193] The vehicle also includes at least one electric motor connected to a transmission engaged with a moving member of the vehicle.

[0194] The generator and said at least one electric motor are advantageously connected via a relay electrical reserve with a capacity of between 0.2 and 2.2 Watt-hours per kilo of vehicle to be equipped (Wh / kg of vehicle), i.e. much lower than a power battery conventionally used in electric vehicles.

[0195] The drive train further comprises an accelerator control movable between a stop position and a maximum acceleration position and connected to an electronic control circuit comprising a controller programmed to power the electric motor from the relay electrical reserve according to a signal captured by at least one sensor fitted to the vehicle.

[0196] Using a more efficient compressed air piston engine, i.e. one that consumes less air for equivalent power than a conventional compressed air engine, therefore presents an essential advantage for developing this type of hybrid powertrain.

[0197] It is therefore also possible to control the exhaust in the same way, with the same type of valve according to the invention, but positioned at the air exhaust outlet, for example in a 4-stroke cycle.

[0198] The injection devices (and exhaust devices when used at the exhaust outlet to control the exhaust) according to the invention have been described with a two-stroke engine.

[0199] It is of course possible to adapt them to a four-stroke engine, in particular by equipping the exhaust with valves identical to those described for injection, but whose operation is adapted to open the passage(s) in order to eject the air used during the previous phase.

[0200] Air management during the cycle can be advantageously improved thanks to the invention. In particular, by cleverly managing the air compressed by the piston during its ascent, the piston can rise with less energy and the intake of compressed air can be delayed as much as possible to the top dead center of the piston.

[0201] Thus, the invention also relates to a method for managing air in a powertrain provided with a main compressed air tank and a compressed air engine comprising:– an engine block comprising N cylinders, N being an integer greater than or equal to 1, the or each cylinder having a chamber and a piston mounted to move in translation in said chamber between a high position called “top dead center” and a low position called “bottom dead center”, the chamber comprising an exhaust outlet; and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head comprising, for each chamber, at least one compressed air intake valve, and a discharge / charge valve;the method being characterized in that it comprises the following successive steps, for each cylinder:1) Compression by the piston of the air present in the chamber;2) Discharging compressed air from the chamber to a buffer reserve through the discharge / charge valve;3) Admitting compressed air into the piston chamber from the main reservoir through the inlet valve;4) Charging the air stored in the buffer reserve to the piston chamber through the discharge / charge valve;5) Exhausting the expanded air from the piston chamber to the outside through the exhaust outlet;

[0202] In the present invention, the following terms or expressions are defined as follows:- Compressed air: air stored at high pressure in a main reservoir and serving as the main driving source.- Compressed air: residual air present in the chamber after exhaust and compressed by the piston rising.- Main reservoir: main storage volume for high pressure compressed air.- Buffer reserve: temporary storage volume for compressed air coming from the chamber- Intake / exhaust of compressed air:* Intake is the injection of compressed air into the piston chamber from the main reservoir through an intake valve.* Exhaust is the ejection of expanded air from the piston chamber to the outside of the engine through an exhaust outlet.- Compressed air discharge / charge:* Compressed air discharge is the evacuation, or expulsion, of compressed air from the piston chamber to a buffer reserve through a discharge / charge valve.* Air charge is the reintroduction of air from the buffer reserve to the piston chamber through the discharge / charge valve.

[0203] The invention also relates to an air management circuit for a compressed air engine connected to a main compressed air reservoir, the engine comprising:– an engine block comprising N cylinders, N being an integer greater than or equal to 1, the or each cylinder having a chamber and a piston mounted to move in translation in said chamber between a high position called "top dead center" and a low position called "bottom dead center", the chamber comprising an exhaust outlet; and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head comprising, for each chamber, at least one compressed air intake valve;the air management circuit being characterized in that it comprises:* a discharge / charge valve in the chamber of each cylinder* a buffer reserve in fluid communication with each discharge / charge valve* a means for controlling each discharge / charge valve.

[0204] The buffer reserve comprises either a common volume connected to the discharge / charge valve of each chamber, or a multitude of individual volumes each connected to a discharge / charge valve.

[0205] The invention also relates to a compressed air engine comprising:– an engine block comprising N cylinders, N being an integer greater than or equal to 1, the or each cylinder having a chamber and a piston mounted movable in translation in said chamber between a high position called "top dead center" and a low position called "bottom dead center", the chamber comprising an exhaust outlet; and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head comprising,* in the chamber of each cylinder:_ a compressed air intake valve,_ a discharge / charge valve for air compressed by the rise of the piston, in use;* and a buffer reserve in fluid communication with each discharge / charge valve.

[0206] A first embodiment of the method according to the invention is described in Figures 11 to 16 for an engine equipped with the injection device described and illustrated previously.

[0207] Each 16 comprises three sub-figures: a first numbered “a” which illustrates a schematic cylinder seen in section, a second numbered “b” which illustrates the bar seen from above, and a third numbered “c” which is a polar diagram illustrating the position of the cylinder in the engine cycle of the method according to the invention.

[0208] In a polar diagram, the engine cycle is indicated as a function of the position in degrees of the crankshaft which has a rotational movement ranging from 0° to 360° (i.e. a return to 0°).

[0209] The engine's Top Dead Center (TDC) is the highest position of the piston in the engine cylinder. In the examples shown, it is set at the 90° position of the crankshaft.

[0210] The bottom dead center (BDC) of the engine is the lowest position of the piston in the engine cylinder. It is therefore fixed, in the examples illustrated, at the 270° position of the crankshaft (i.e. 180° after / before TDC).

[0211] In the illustrated examples, the angles are given for informational purposes and are not limiting, and make it possible to simplify the understanding of the engine cycle obtained by the air management method according to the invention.

[0212] On each polar diagram illustrated: - the compressed air injection phase by the intake valve is represented by a PHI sector in a continuous line between 85° and 120°, thanks to the delayed injection described previously; - the exhaust phase of the expanded air by the exhaust outlet 12 is represented by a PHE sector in dashed lines between 210° and 330°.

[0213] According to the air management method of the invention described in more detail below, the engine cycle comprises two additional phases, illustrated on each polar diagram: - a “discharge” phase of the compressed air by the piston rising into a buffer reserve outside the chamber, represented by a dotted PHD sector, between 15° and 50°; and - a “charge” phase of the compressed air from the buffer reserve to the chamber, represented by a dashed PHC sector, between 130° and 165°.

[0214] Again, these values ​​are given as a guide. In particular, the start of the discharge phase can be chosen according to the desired pressure for the compressed air, this air then being temporarily recovered in a buffer reserve and then reintroduced to add pressure when the piston descends.

[0215] Similarly, the discharge phase can stop immediately before the start of the injection phase (in the example it would stop at 85°) in order to facilitate the rise of the piston as much as possible, or, as illustrated, the discharge phase can stop a few degrees before the injection phase (it would then stop a few degrees to a few tens of degrees before 85°, here 35° before since it stops at 50°) to create a slight compression which, if it slightly opposes the rise of the piston, generates a rise in temperature of the chamber, favorable to the expansion of the compressed air injected subsequently.

[0216] The person skilled in the art will adapt the settings of the system according to the invention according to the desired results, in particular in terms of compression ratio.

[0217] In detail, in the first embodiment of Figures 11 to 16, the cylinder head B comprises, as in the embodiment of Figures 2 and 3, a compressed air intake duct 11 connected to the main reservoir 9 for storing high-pressure compressed air (not shown in the figures for the sake of clarity). The air intake duct 11 comprises at least one intake passage (here two are shown) 110, 111, substantially parallel to the direction of injection of the compressed air into the chamber 5 of the piston 1.

[0218] The cylinder head B is also internally crossed by a channel 13 perpendicular and transverse to the intake passages 110, 111 of the intake duct 11.

[0219] As previously, the channel 13 is equipped with a compressed air intake valve comprising a bar 20 arranged in a sliding manner in the channel 13, the bar 20 comprising a first part 21 provided with as many intake orifices as the cylinder head comprises intake passages 110, 111 (here two), and a second part 22 for position control.

[0220] The intake valve further comprises a return means 40 and, on either side of the second position control part 22, at least one actuator 50 connected to a power source (electric or pneumatic) controllable by a control unit (not shown).

[0221] According to this aspect of the invention, the intake valve provides an additional function in managing the air compressed by the rising piston. It is therefore an air intake and discharge / charge valve.

[0222] To this end, the cylinder head B also comprises a discharge / charge duct 400 for compressed air comprising at least one discharge / charge passage (here two are illustrated) 401, 402, substantially parallel to the direction of injection of the compressed air into the chamber 5 of the piston 1. The channel 13 is therefore perpendicular and transverse to said at least one discharge / charge passage.

[0223] For this purpose also, the first part 21 of the bar comprises two types of orifices (see figure 11b): at least one intake orifice (here two) intended to align, in operation, with said at least one air intake passage 110, 111 of the compressed air intake duct 11, and at least one discharge / charge orifice (here two) 410, 411 intended to align, in operation, with said at least one discharge / charge passage 401, 402 of the discharge / charge duct 400 of compressed air.

[0224] The inlet ports 110, 111 and the discharge / charge ports 410, 411 are arranged on the first part 21 of the bar 20, such that the movement of the bar allows three positions of use of the bar: - An “open” position of the inlet passage 110, 111 in which said at least one inlet port 210, 211 carried by the first part 21 of the bar 20 is entirely aligned with said at least one corresponding inlet passage 110, 111, while said at least one discharge / charge port 410, 411 carried by the first part 21 of the bar 20 is entirely offset from said at least one corresponding discharge / charge passage 401, 402;- A "closed" position of said at least one intake passage 110, 111 and said at least one discharge / charge passage 401, 402, in which said at least one intake orifice 210, 211 carried by the first part 21 of the bar 20 is entirely offset relative to said at least one corresponding intake passage 110, 111, and said at least one discharge / charge orifice 410, 411 carried by the first part 21 of the bar 20 is entirely offset relative to said at least one corresponding discharge / charge passage 401, 402;- A compressed air discharge / charge position in which said at least one intake passage 110, 111 is closed and said at least one discharge / charge passage 401, 402 is open, said at least one intake port 210, 211 carried by the first part 21 of the bar 20 being entirely offset with respect to said at least one corresponding intake passage 110, 111, and said at least one discharge / charge port 410, 411, carried by the first part 21 of the bar 20, is entirely aligned with respect to said at least one corresponding discharge / charge passage 401, 402.;

[0225] In the PHI injection phase, the bar is in the open position, in the PHD discharge phase, the bar is in the discharge / charge position, and in the PHC charge phase, the bar is in the discharge / charge position.

[0226] Between these phases, as well as in the PHE exhaust phase, the bar is in the closed position for all passages.

[0227] The movement of the bar is between the open position and the discharge / load position, the closing position being intermediate, in the movement of the bar, between the two aforementioned positions.

[0228] For this purpose, each of the intake passages and the discharge / charge passages has an identical determined opening section S1, and two adjacent intake passages and two adjacent discharge / charge passages are spaced apart by a determined distance D1 which is equal to at least twice the opening section of the intake passages.

[0229] Furthermore, two adjacent intake ports and two adjacent discharge / charge ports are spaced apart by the same distance D1 which separates two adjacent intake and discharge / charge passages of the cylinder head and each intake port and each discharge / charge port has an opening section S1, identical to that of the intake passages and the discharge / charge passages made in the cylinder head B. What is important, as described below, is that the movement of the bar relative to the intake passages and the discharge / charge passages made in the cylinder head B allows a position of the bar between (i.e. including) the open position and the discharge / charge position, the closed position being intermediate, in the movement of the bar, between the two aforementioned positions.

[0230] The configuration illustrated in, is the discharge / charge position. In this configuration, the discharge / charge ports 410, 411 carried by the first portion 21 of the bar 20 are fully aligned with the discharge / charge passages 401, 402. Furthermore, the intake ports 210, 211 carried by the first portion 21 of the bar 20 are fully offset from the intake passages 110, 111.

[0231] This configuration allows the implementation of a discharge phase () or a charge phase ().

[0232] The illustrated position P11 corresponds to the unloading phase. As illustrated in Figure 11c, the position P11 is located in the PHD sector, at 30° crankshaft orientation.

[0233] When the piston 1 rises (arrow F6), the air present in the chamber, above the piston, is evacuated (arrow F7) through the discharge / charge passages 401, 402 in the discharge / charge conduit 400 towards the buffer reserve 500.

[0234] In the illustrated embodiment, this phase is carried out after compression since the discharge phase PHD (therefore opening of the discharge / charge passages) begins at 15° while the exhaust phase PHE ends at 330°.

[0235] In, the piston continues to rise (arrow F6). The bar has been moved so that the intake ports and the discharge / charge ports are completely offset from the passages, i.e. they all face the cylinder head wall and are thus all closed. The air in the chamber above the piston can no longer discharge to the buffer reserve 500. It is therefore compressed and heats up.

[0236] As shown in Figure 12c, position P12 is between the PHD sector and the PHI injection sector, at 60° crankshaft orientation.

[0237] The position P13 illustrated in, is the open position of the intake passages 110, 111 in which the intake orifices 210, 211 carried by the first part 21 of the bar 20 are entirely aligned with the intake passages 110, 111. Furthermore, the discharge / charge orifices 410, 411 carried by the first part 21 of the bar 20 are entirely offset from the discharge / charge passages 401, 402.

[0238] As illustrated in Figure 13c, position P13 is in the PHI sector, at 105° crankshaft orientation. In this position, the piston has passed its top dead center and the injection of compressed air into the chamber (arrow F8) and its expansion push the piston downwards (arrow F9), because it cannot escape through the discharge / charge passages 401, 402 which are closed.

[0239] The expansion of the compressed air is all the greater as the chamber has been heated by the compressed air between the end of the PHD discharge phase (here at 50°) and the start of the PHI injection phase (here at 85°).

[0240] Once enough compressed air has been admitted into the chamber, the injection phase ends. The pressure in the chamber is very high, but will decrease as the air expands and piston 1 descends.

[0241] This situation is illustrated in Figure 14c where position P14 is between the intake sector PHI and the charge sector PHC, at 125° crankshaft orientation.

[0242] In this position, the bar 20 is in the position of closing the intake passages 110, 111 and the discharge / charge passages 401, 402. The intake ports 210, 211 are entirely offset from the intake passages 110, 111, and the discharge / charge ports 410, 411 are entirely offset from the discharge / charge passages 401, 402.

[0243] Once the pressure in the chamber is lower than the pressure of the compressed air stored in the buffer reserve, the bar 20 is again moved to the discharge / charge position: the intake passages 110, 111 are closed and the discharge / charge passages 401, 402 are open.

[0244] As shown in Figure 15c, position P15 is in the PHC sector, at 150° crankshaft orientation, and corresponds to the load phase.

[0245] In this position shown in, compressed air is charged (arrow F10) into the chamber, increasing the pressure and therefore the force applied to push the piston down, thus adding extra power.

[0246] Once the compressed air is fully charged into the chamber, bar 20 is again driven to move it to the position of total closure of all passages, as shown in. The piston continues to descend. In the, position P16 is in the PHE sector, at 325° of crankshaft orientation. The piston has therefore passed its bottom dead center.

[0247] The exhaust outlet 12 has been opened by the descent of the piston, and the air present in the chamber escapes to the outside of the engine.

[0248] Driven by the crankshaft driven by the other cylinders of the engine, piston 1 rises and the cycle begins again.

[0249] This first embodiment has the advantage of only controlling a single bar. However, this control must be done between three positions: two extreme positions (open position and discharge / charge position) and an intermediate position (closed position).

[0250] It therefore requires very precise adjustment.

[0251] The second method of implementing the process is of simpler design. In this figure, the cylinder head B is seen from above and one of the chambers 5 that it covers is visible through transparency.

[0252] In this second embodiment, the cylinder head is provided, above the chamber of each cylinder, with two identical valves 601-602 arranged next to each other, each valve being similar to that described in Figures 2 and 3, one being controlled for the admission of compressed air into the chamber, the other being controlled for the discharge and charging of the air compressed by the piston.

[0253] More specifically, the cylinder head comprises: - an intake duct comprising at least one intake passage 110, 111, 112, 113, 114, substantially parallel to the direction of injection of the compressed air into the chamber 5, and a channel 13a perpendicular and transverse to said at least one intake passage - a first compressed air intake valve 601; - a discharge / charge duct comprising at least one discharge / charge passage 401, 402, 403, 404, 405 substantially parallel to the direction of injection of the compressed air into the chamber 5, and a channel 13b perpendicular and transverse to said at least one discharge / charge passage, and - a second valve 602 for discharging / charging the compressed air during the rise of the piston.

[0254] Each valve comprises, as previously described, a bar 20b, respectively 20c, slidably arranged in its corresponding channel 13a, respectively 13b. Each bar 20b, respectively 20c comprises a first part 21 provided with at least one orifice: the bar 20b comprises inlet orifices 210, 211, 212, 213, 214 and the bar 20c comprises discharge / charge orifices 410, 411, 412, 413, 414;

[0255] As described above, each bar also comprises a second position control part 22, a return means 40 of the bar 20 and at least one actuator 50.

[0256] For the implementation of the air management method according to the invention, the intake valve Sa is controlled in the open position during the intake phase PHI, and in the closed position for the rest of the cycle (therefore during the discharge phase PHD, the charge phase PHC, the exhaust phase PHE, and between the phases). At the same time, the discharge / charge valve is controlled in the open position during the discharge phase PHD, during the charge phase PHC, and in the closed position for the rest of the cycle (therefore during the intake phase PHI, the exhaust phase PHE, and between the phases).

[0257] A third embodiment of a device for managing the air compressed by the piston is illustrated in Figures 18 to 23. This embodiment allows very rapid and efficient management, by combining the advantages of the first and second embodiments of Figures 11 to 17.

[0258] This third embodiment is similar to the embodiment illustrated in Figures 4 to 6, the cylinder head comprising two valves 701-702 whose bars 20d-20e are arranged one above the other, and in opposition, that is to say head to tail, on either side of the axis of symmetry of the cylinder.

[0259] As for the embodiment of figures 11 to 16, the cylinder head B comprises, for each cylinder, a compressed air intake duct 11 connected to the main tank 9 for storing high-pressure compressed air (not shown in the figures for the sake of clarity), and a compressed air discharge / charge duct 400. These ducts 11 and 400 are of identical structure and function to what has been described for figures 11 to 16.

[0260] Unlike these figures, the cylinder head B is also internally crossed by two channels 13 arranged one above the other (or alternatively a double height channel to receive two superimposed bars), and perpendicular and transverse to the intake passages 110, 111 of the intake duct 11 and to the discharge / charge passages 401-402 of the discharge / charge duct 400.

[0261] Valves 701-702 each provide both compressed air intake and compressed air discharge / charge functions.

[0262] For this purpose, the bar 20d-20e of each valve has as many intake ports as the intake duct 11 has intake passages, and as many discharge / charge ports as the discharge / charge duct has discharge / charge passages.

[0263] The inlet ports 110, 111 and the discharge / charge ports 410a, 411a, 410b, 411b are arranged on the first part 21 of each bar 20d-20e, such that each bar 20d-20e can move between (i.e. including) only two operating positions:- A simultaneous position PSO of opening the inlet passages 110, 111 and closing the discharge / charge passages, in which each inlet port 210a, 211a, 210b, 211b carried by the first part 21 of each bar 20d-20e is fully aligned with a corresponding inlet passage 110, 111, while each discharge / charge port 410a, 411a, 410b, 411b carried by the first part 21 of each bar 20d-20e is entirely offset relative to the corresponding discharge / charge passage 401, 402;- A simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402, in which each intake orifice 210a, 211a, 210b, 211b carried by the first part 21 of each bar 20d-20e is entirely offset relative to the corresponding intake passage 110, 111, and each discharge / charge orifice 410a, 411a, 410b, 411b carried by the first part 21 of each bar 20d-20e is entirely aligned relative to the corresponding discharge / charge passage 401, 402.;

[0264] The bars 20d, 20e of the valves 701-702 being in opposition, the intake ports and the discharge / charge ports are arranged between them and in relation to the intake passages and the discharge / charge passages in such a way that it is possible to control the two bars so as to obtain, in operation, the three operating situations: the opening of the intake passages to inject the compressed air into the chamber, while the discharge / charge passages are closed, the opening of the discharge / charge passages to discharge the compressed air from the chamber or to charge the compressed air stored in the buffer reserve into the chamber, while the intake passages are closed, and finally, the closing of all the intake and discharge / charge passages.

[0265] Figures 18 to 23 correspond respectively to the phases of the engine cycle illustrated by Figures 11 to 16. The corresponding polar diagrams would be identical to those illustrated in Figures 11c to 16c.

[0266] Illustrates the discharge phase PHD of the air compressed by the piston out of the chamber and towards the buffer reserve 500 (this figure therefore corresponds to the phase illustrated in and at position P11 on the polar diagram of figure 11c).

[0267] For this purpose, the bar 20d and the bar 20e are both in the simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402. The discharge / charge passages are then open and the intake passages are closed. The compressed air can thus discharge out of the chamber (arrow F7) towards the buffer reserve.

[0268] Illustrates the next phase in which the chamber is closed after the discharge of the compressed air (this figure therefore corresponds to the phase illustrated in and at position P12 on the polar diagram of Figure 12c).

[0269] To this end, the bar 20e remains in the simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402, while the bar 20d is controlled to move (arrow F12) in the simultaneous position PSO of opening the intake passages 110, 111 and closing the discharge / charge passages 401, 402. The intake passages and the discharge / charge passages are then closed.

[0270] The air above the piston can no longer escape from the chamber. It is then compressed by the piston and heats up. Moving to this stage therefore only requires the control of a single bar.

[0271] Illustrates the next phase which is the PHI admission phase in which the compressed air is injected (arrow F13) into the chamber (this figure therefore corresponds to the phase illustrated in and at position P13 on the polar diagram of figure 13c).

[0272] For this purpose, the bar 20d remains in the simultaneous position PSO of opening the intake passages 110, 111 and closing the discharge / charge passages 401, 402, while the bar 20e is driven to move (arrow F14) in the simultaneous position PSO of opening the intake passages 110, 111 and closing the discharge / charge passages 401, 402. The discharge / charge passages are then closed and the intake passages are open so that the compressed air can be injected into the chamber.

[0273] Again, moving to this stage only requires ordering a single bar.

[0274] Illustrates the next phase in which the chamber is closed after the admission of compressed air into the chamber (this figure therefore corresponds to the phase illustrated in and at position P14 on the polar diagram of figure 14c).

[0275] To this end, the bar 20e remains in the simultaneous position PSO of opening the intake passages 110, 111 and closing the discharge / charge passages 401, 402, while the bar 20d is controlled to move (arrow F15) into the simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402. The intake passages and the discharge / charge passages are then closed.

[0276] Again, moving to this stage only requires ordering a single bar.

[0277] Illustrates the next phase which is the PHC charging phase of the stored compressed air from the buffer reserve to the chamber (arrow F16). This figure therefore corresponds to the phase illustrated in and at position P15 on the polar diagram of figure 15c.

[0278] To this end, the bar 20d remains in the simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402, while the bar 20e is controlled to move (arrow F17) in the simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402. The discharge / charge passages are then open and the intake passages are closed.

[0279] As before, moving to this stage therefore only requires ordering a single bar.

[0280] Finally, Laillustrates the next phase which is the PHE exhaust phase and in which the chamber is closed after the compressed air is charged into the chamber from the buffer reserve (this figure therefore corresponds to the phase illustrated at and at position P16 on the polar diagram of figure 16c).

[0281] To this end, one of the two bars 20d or 20e is moved. This does not matter much since to restart the cycle, it will be necessary to move this bar again to return to the position of the. On the, it is the bar 20d which remains in the simultaneous position PSF of closing the intake passages 110, 111 and opening the discharge / charge passages 401, 402, while the bar 20e is controlled to move (arrow F18) to the simultaneous position PSO of opening the intake passages 110, 111 and closing the discharge / charge passages 401, 402. The intake passages and the discharge / charge passages are then closed.

[0282] Again, moving to this stage only requires ordering a single bar.

[0283] For the implementation of this embodiment, each of the intake passages and the discharge / charge passages has a determined opening section S1 and, as in the embodiment of Figures 4 to 6, two adjacent intake passages and two adjacent discharge / charge passages are spaced apart by a determined distance D1 which is equal to at least once the opening section of the intake passages (whereas it is at least twice for the embodiment of Figures 11 to 16).

[0284] Furthermore, two adjacent intake ports and two adjacent discharge / charge ports are spaced apart by the same distance D1 which separates two adjacent intake and discharge / charge passages of the cylinder head and each intake port and each discharge / charge port has an opening section S1, identical to that of the intake passages and the discharge / charge passages made in the cylinder head B.

[0285] As before, what matters is that the movement of the bars relative to the intake passages and the discharge / charge passages of cylinder head B allows selective opening / closing of the intake passages and the discharge / charge passages.

[0286] It is understood that this embodiment is particularly advantageous, because the transition from one step to the other only requires the movement of one of the two blades, which makes it fast, low energy consumption, reliable, because the bars move little in translation and only between two easily determined positions.

[0287] Furthermore, the management, in the engine cycle, of the compressed air by the rise of the piston in the chamber, partially discharging it and recharging it after the admission of the compressed air, significantly improves the power of the engine.

[0288] The invention therefore also relates to an engine comprising a cylinder head equipped with a device according to one of the two embodiments of figures 2 and 3, and 4 to 6, and capable of implementing a delayed injection of compressed air into the piston chamber.

[0289] Preferably, the invention also relates to an engine comprising a cylinder head equipped with a device according to one of the three embodiments of figures 11 to 16, 17 and 18 to 23, and capable of managing compressed air according to the method according to the invention.

Claims

Electronic compressed air injection device intended to equip a cylinder head (B) of a compressed air engine which also comprises at least one piston (1) intended to move in a chamber (5), the cylinder head (B) being internally traversed by an intake duct (11) comprising at least one intake passage (110, 111, 112, 113, 114) substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston and by at least one channel (13) perpendicular and transverse to said at least one intake passage, said device comprising at least one compressed air intake valve (S), each valve being adapted to operate with a piston of the engine when the device is in the position of use in the engine, and comprising: - a bar (20) arranged in a sliding manner in said at least one channel (13), said bar (20) comprising a first part (21) provided with at least one intake orifice (210, 211, 212, 213, 214),and a second position control part (22), the valve further comprising: - a return means (40) for the bar (20) and - on either side of the second position control part (22), at least one actuator (50) connected to an energy source controllable by a control unit, the latter being connected to at least one piston position sensor, the control unit being programmed to control an energy supply to the actuator from the energy source and to move, in operation, the bar (20) into a position between an open position of said at least one intake passage (110, 111, 112, 113, 114) in which said at least one intake orifice (210, 211, 212, 213, 214) carried by the first part (21) is entirely aligned with said at least one intake passage (110, 111, 112, 113, 114), and a closing position of said at least one intake passage (110, 111, 112, 113,114) of the intake valve in which said at least one intake orifice (210, 211, 212, 213, 214) carried by the first part (21) is entirely offset from said at least one intake passage (110, 111, 112, 113, 114)., Electronic compressed air injection device intended to equip a cylinder head (B) of a compressed air engine which also comprises at least one piston (1), intended to move in a chamber (5), the cylinder head (B) being internally traversed by an intake duct (11) comprising a plurality of intake passages (110, 111, 112, 113, 114) of determined opening section, and substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston, the intake passages being spaced apart by a determined distance (D1) greater than or equal to an opening section of the intake passages, and by at least one channel (13) perpendicular and transverse to all the intake passages, said device comprising at least one compressed air intake valve (S, S'), each valve being adapted to operate with a piston of the engine when the device is in the position of use in the engine and comprising a bar (20,20a) slidably arranged in said at least one channel (13), said bar (20, 20a) comprising a first part (21a) comprising as many intake ports (210, 211, 212, 213, 214; 210a, 211a, 212a, 213a, 214a) as the cylinder head (B) comprises compressed air intake passages, the intake ports (210, 211, 212, 213, 214; 210a, 211a, 212a, 213a, 214a) being spaced apart by the same distance (D1) as the intake passages, and a second part (22, 22a) for position control, the valve (S, S') further comprising a return means (40,40a) of the bar (20,20a) and, on either side of the second position control part (22,22a), actuators (50,50a) connected to an energy source controllable by a control unit, the latter being connected to at least one piston position sensor, the control unit being programmed to control the energy supply of the actuators from the energy source, and to move, in operation,the bar (20, 20a) in a position between an open position of the intake passages (110, 111, 112, 113, 114) in which the intake orifices (210, 211, 212, 213, 214; 210a, 211a, 212a, 213a, 214a) carried by the first part (21, 21a) are entirely aligned with the intake passages (110, 111, 112, 113, 114), and a closed position in which the intake orifices (210, 211, 212, 213, 214; 210a, 211a, 212a, 213a, 214a) carried by the first part (21,21a) are entirely offset from the intake passages (110, 111, 112, 113, 114)., Device according to claim 2 wherein the valve (S') comprises another bar (20a) arranged slidably in said at least one channel (13), this other bar (20a) comprising a first part (21a) comprising as many intake orifices (210a, 211a, 212a, 213a, 214a) as the cylinder head (B) comprises compressed air intake passages, the intake orifices (210a, 211a, 212a, 213a, 214a) being spaced apart by the same distance (D1) as the intake passages, and a second part (22a) for position control, the two bars (20, 20a) being arranged head to tail, the valve (S') further comprising a return means (40a) of the other bar (20a) and, on either side on the other side of the second position control part (22a), actuators (50a) connected to an energy source controllable by the control unit, the latter being connected to at least one piston position sensor,the control unit being programmed to control the energy supply of the actuators from the energy source and to move the other bar (20a) into a position between an open position of the intake passages (110, 111, 112, 113, 114) in which the intake orifices (210a, 211a, 212a, 213a, 214a) carried by the other bar (20a) are entirely aligned with the intake passages (110, 111, 112, 113, 114), and a closed position in which the intake orifices (210a, 211a, 212a, 213a, 214a) carried by the other bar (20a) are entirely offset from the intake passages (110, 111, 112, 113, 114)., Device according to claim 1, wherein the cylinder head (B) is also internally traversed by a discharge / charge duct (400) for compressed air comprising at least one discharge / charge passage (401, 402, 403, 404, 405) traversed perpendicularly and transversely by a channel (13b) arranged next to the channel (13) receiving the intake valve (601), the device further comprising a discharge / charge valve (602) arranged next to the intake valve (601), and comprising: - a bar (20c) arranged slidably in said channel (13b), said bar (20c) comprising a first part (21) provided with at least one discharge / charge orifice (410, 411, 412, 413, 414), and a second part (22) for position control, the valve (602) further comprising: - a return means (40) for the bar (20c) and - on either side of the second position control part (22),at least one actuator (50) connected to an energy source controllable by a control unit, the latter being connected to at least one piston position sensor, the control unit being programmed to control an energy supply of the actuator from the energy source and to move, in operation, the bar (20c) into a position between an open position of said at least one discharge / charge passage (401, 402, 403, 404, 405) in which said at least one discharge / charge orifice (410, 411, 412, 413, 414) carried by the first part (21) is entirely aligned with said at least one discharge / charge passage (401, 402, 403, 404, 405), and a closed position of said at least one discharge / charge passage (401, 402, 403, 404, 405) of the intake valve in which said at least one discharge / charge port (410, 411, 412, 413,414) carried by the first part (21) is entirely offset relative to said at least one discharge / charge passage (401, 402, 403, 404, 405)., Device according to claim 2, in which the cylinder head (B) is also internally traversed by a discharge / charge duct (400) for compressed air comprising at least one discharge / charge passage (401, 402) traversed perpendicularly and transversely by the channel (13), and in which the first part (21) of the bar (20) further comprises at least one discharge / charge orifice (410, 411) intended to align, in operation, with said at least one discharge / charge passage (401, 402) of the discharge / charge duct (400), the inlet orifices (110, 111) and the discharge / charge orifices (410, 411) being arranged on the first part (21) of the bar (20) such that in operation, when the bar (20) is moved by the control unit into a position between:- the position opening of the intake passage (110, 111), wherein said at least one intake orifice (210,211) carried by the first portion (21) of the bar (20) is entirely aligned with said at least one intake orifice (110, 111), while said at least one discharge / charge orifice (410, 411) carried by the first portion (21) of the bar (20) is entirely offset from said at least one discharge / charge passage (401, 402);- the "closed" position of said at least one intake passage (110, 111) and said at least one discharge / charge passage (401, 402), in which said at least one intake orifice (210, 211) carried by the first portion (21) of the bar (20) is entirely offset from said at least one intake passage (110, 111), and said at least one discharge / charge orifice (410, 411) carried by the first portion (21) of the bar (20) is entirely offset from said at least one discharge / charge passage (401, 402); the bar (20) is entirely offset from said at least one discharge / charge passage (401, 402); and- a compressed air discharge / charge position in which said at least one intake passage (110,111) is closed and said at least one discharge / charge passage (401, 402) is open, said at least one inlet orifice (210, 211) carried by the first part (21) of the bar (20) being entirely offset with respect to said at least one inlet passage (110, 111), and said at least one discharge / charge orifice (410, 411) carried by the first part (21) of the bar (20) being entirely aligned with respect to said at least one discharge / charge passage (401, 402); the closed position being intermediate, in the movement of the bar, between the open position and the discharge / charge position., Device according to claim 3 in which the cylinder head (B) is also internally traversed by a discharge / charge duct (400) of compressed air comprising at least one discharge / charge passage (401, 402) traversed perpendicularly and transversely by the channel (13), and in which the first part (21) of each bar (20d, 20e) further comprises as many discharge / charge orifices (410, 411) as the discharge / charge duct (400) comprises discharge / charge passages (401, 402), the inlet orifices (110, 111) and the discharge / charge orifices (410, 411) being arranged on the first part (21) of each bar (20d, 20e) such that in operation, the control unit is programmed to control the energy supply of the actuators from the energy source and move each bar (20d, 20e) between two positions of use: - A simultaneous position (PSO) of opening of the intake passage (110,111) and closing the discharge / charge passage (401, 402), wherein each inlet port (210a, 211a, 210b, 211b) carried by the first part (21) of each bar (20d-20e) is entirely aligned with said at least one corresponding inlet passage (110, 111), while each discharge / charge port (410a, 411a, 410b, 411b) carried by the first part (21) of each bar (20d-20e) is entirely offset from said at least one corresponding discharge / charge passage (401, 402); and- A simultaneous position (PSF) of closing said at least one intake passage (110, 111) and opening said at least one discharge / charge passage (401, 402), in which each intake orifice (210a, 211a, 210b, 211b) carried by the first part (21) of each bar (20d-20e) is entirely offset relative to said at least one corresponding intake passage (110, 111), and each discharge / charge orifice (410a, 411a, 410b,411b) carried by the first part (21) of each bar (20d-20e) is fully aligned with respect to said at least one corresponding discharge / charge passage (401, 402)., Device according to any one of claims 1 to 6, wherein the second position control part (22, 22a) of the or each bar (20, 20a) is magnetic, and wherein the actuator(s) are electromagnets (50), the energy source being an electrical source. Device according to any one of claims 1 to 6, wherein the actuator(s) are pneumatic actuators, the energy source being a pneumatic source of compressed air. Compressed air engine cylinder head equipped with an injection device according to claim 1, internally traversed by at least one intake passage (110) substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston and by at least one channel (13) perpendicular and transverse to said passage. Cylinder head according to claim 9, furthermore internally traversed by at least one discharge / charge passage (401, 402) substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston and by a channel (13b) perpendicular and transverse to said passage. Compressed air engine cylinder head equipped with an injection device according to claim 2 or 3, internally traversed by a plurality of intake passages (110, 111, 112, 113, 114) of determined opening section, and substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston, the intake passages being spaced apart by a determined distance (D1) greater than or equal to the opening section of the intake passages, and by at least one channel (13) perpendicular and transverse to all the intake passages. Cylinder head according to the preceding claim when it depends on claim 2, further traversed internally by a plurality of discharge / charge passages (401, 402) of determined opening section, and substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston, the discharge / charge passages (401, 402) being spaced apart by a determined distance (D1) greater than or equal to the opening section of the intake passages, and by at least one channel (13) perpendicular and transverse to all the intake passages. Cylinder head according to the preceding claim when it depends on claim 3, further traversed internally by a plurality of discharge / charge passages (401, 402) of opening section identical to the opening section of the intake passages (110, 111, 112, 113, 114), and substantially parallel to the direction of injection of the compressed air into the chamber (5) of the piston, the intake passages (110, 111, 112, 113, 114) and the discharge / charge passages (401, 402) being spaced apart by a determined distance (D1) greater than or equal to twice the opening section of the intake passages. A compressed air engine comprising a cylinder head according to any one of claims 9 to 13. Hybrid powertrain intended to equip a vehicle comprising a high-pressure compressed air reservoir connected to a compressed air piston engine according to claim 14, engaged with an electric generator to generate electricity when it is driven by the compressed air piston engine, the electric generator being connected to at least one electric motor itself connected to a transmission engaged with a moving member of the vehicle. Powertrain according to claim 15, in which the generator and said at least one electric motor are connected via a relay electrical reserve with a capacity of between 0.2 and 2.2 Watt-hours per kilo of vehicle to be equipped (Wh / kg of vehicle). Powertrain according to claim 16, further comprising an accelerator control movable between a stop position and a maximum acceleration position and connected to an electronic control circuit comprising a controller programmed to power the electric motor from the relay electrical reserve as a function of a signal captured by at least one sensor fitted to the vehicle. A generator set comprising a high pressure compressed air reservoir connected to a compressed air piston engine according to claim 14, engaged with an electric generator for generating electricity when driven by the compressed air piston engine. Method for managing air in a powertrain equipped with a main compressed air reservoir and a compressed air engine comprising:– an engine block comprising N cylinders, N being an integer greater than or equal to 1, the or each cylinder having a chamber and a piston mounted to move in translation in said chamber between a high position called “top dead center” and a low position called “bottom dead center”, the chamber comprising an exhaust outlet; and– a cylinder head associated with the engine block and capable of closing the or each chamber, the cylinder head comprising, for each chamber, at least one compressed air intake valve and a discharge / charge valve;the method being characterized in that it comprises the following successive steps, for each cylinder:1) Compression by the piston of the air present in the chamber;2) Discharge of the compressed air from the chamber to a buffer reserve through the discharge / charge valve;3) Admission of compressed air into the piston chamber from the main reservoir through the inlet valve;4) Charging of the air stored in the buffer reserve to the piston chamber through the discharge / charge valve;5) Exhaust of the expanded air from the piston chamber to the outside through the exhaust outlet;

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