An active chamber engine operating according to a three-phase thermodynamic cycle including an isobaric and isothermal transfer phase, a phase of polytropic expansion with work, and an exhaust phase at ambient pressure, the engine comprising:
- at least one cylinder fed with a gas under pressure contained in a high-pressure storage tank;
- at least one piston that is mounted to slide in the at least one cylinder;
- a crankshaft driven by the piston via a connecting rod and crank device;
- a cylinder head that closes the volume of the cylinder at the top, which is swept by the piston, and which includes
- at least one intake duct in which a flow of gas under pressure flows to fill the cylinder,
- an intake orifice for the gas under pressure above the piston, and
- at least one exhaust orifice and one exhaust duct,
- the cylinder head being arranged so that, when the piston is at its top dead center point, the residual volume contained between the piston and the cylinder head is, by construction, reduced to only the minimum gaps enabling contactless operation between the piston and the cylinder head;
- at least one intake valve that cooperates in a sealed manner with a valve seat formed in the cylinder head and which defines the intake orifice;
- wherein the volume of the cylinder swept by the piston is divided into two distinct parts, a first part of the two distinct parts constituting an active chamber that is included in the cylinder and a second part of the two distinct parts constituting an expansion chamber,
- under the continuous thrust of the gas under pressure admitted into the cylinder, at constant working pressure, the volume of the active chamber increases and produces work representing the isobaric and isothermal transfer phase,
- the admission of the gas under pressure into the cylinder is blocked when the maximum volume of the active chamber is reached, the quantity of gas under pressure contained in said active chamber then expanding and pushing back the piston over the second part of its travel which defines the expansion chamber and produces work therefore ensuring the polytropic expansion phase,
- when the piston reaches its bottom dead center point, the exhaust orifice is then opened to ensure the exhaust phase during the upstroke of the piston over the entirety of its travel to its top dead center point,
- the torque and the speed of the engine are controlled by opening and closing the intake valve enabling opening of the intake valve substantially at the top dead center point of the travel of the piston and enabling, by closing the intake valve, modification of an intake duration and/or angular sector, and a passage section of the intake orifice in order, as a function of the pressure of the compressed gas contained in the storage tank and the pressure at the end of the expansion phase, to define the quantity of gas under admitted pressure admitted and the volume of the active chamber,
- the intake valve is mounted to be mobile in axial displacement between a low closed position in which the intake valve bears in a sealed manner on the valve seat and a high open position,
- in its opening direction, the intake valve moves axially in the direction opposite to that of the flow of the flow of gas under pressure for filling the cylinder,
- in its closed position, the intake valve is maintained closed in an autoclave manner on the valve seat by the pressure in the intake duct and applied to the intake valve,
- the engine further comprises
- a controller configured to control opening of the intake valve, substantially at the top dead center point of the travel of the piston, to cause the intake valve to lift off the valve seat to enable the establishing of the intake pressure in the active chamber, the valve then travelling its complete opening travel under the action of the differential pressure forces exerted by the gas under pressure on the corresponding parts of the intake valve;
- a pneumatic actuator configured to close the intake valve, the pneumatic actuator including an actuator cylinder and a closing piston that is connected to the intake valve to move axially with the intake valve and that is mounted to slide in the actuator cylinder inside which the closing piston defines in a sealed manner a control closure chamber of the actuator;
- at least one intake connection channel that connects the intake duct to a source of gas under pressure that is the upper part of the active chamber of the cylinder or the intake duct or the tank of gas under pressure;
- an active distribution channel that connects said closure chamber to the upper part of the active chamber and an active distribution valve configured to block the circulation of the gas in the active distribution channel, the opening of which is controlled to place the closure chamber in communication with the upper part of the active chamber, to close the intake valve and to produce work that is added to the work of the charge of gas under pressure previously admitted into the active chamber via the intake duct.