Patent Application
20110100321
It concerns an improved rotary power device.
The U.S. Pat. No. 4,086,879 is the closest prior art.
The first rotor 3 comprises a rotor shaft 32, rotatable about the axis 21 of the toroidal cavity 2, and pistons 31 fitted into the toroidal cavity 2.
The second rotor 4 comprises a rotor shaft 42, rotatable about the axis 21 of the toroidal cavity 2, and pistons 41 fitted into the toroidal cavity 2.
The power shaft 5 is oblique, i.e. at an angle, to the toroidal cavity axis 21 and substantially away from the center 22 of the toroidal cavity. The center 22 of the toroidal cavity is its geometrical “center of gravity”.
Two concentric Cardan joints interconnect the power shaft 5 with the rotor shafts 3 and 4. The two Cardan joints are located at one side, away from the toroidal cavity center, in order to be adequately strong for the resulting loads, without limitations from the toroidal cavity geometry.
The Cardan joint 6 comprises a yoke 61 pivotally mounted on the rotor shaft 3 and pivotally mounted on the power shaft 5.
The Cardan joint 7 comprises a yoke 71 pivotally mounted on the rotor shaft 4 and pivotally mounted on the power shaft 5.
The rotation of the power shaft 5 with constant angular velocity causes the rotation of the two rotors 3 and 4 with substantially variable angular velocities, as shown in
The intake cycle starts when a chamber has its minimum displacement and communicates, through the intake port, to the intake manifold. As the power shaft rotates, the displacement of the chamber gradually increases suctioning air or mixture. With the chamber near its maximum displacement, its contact with the intake port ends and the charge is trapped. As the power shaft rotates further, the volume is reduced and the charge into the chamber is compressed. The combustion starts with the chamber near its minimum displacement (some 180 power shaft degrees after the suction started). Further rotation of the power shaft increases the volume of the chamber making the expansion cycle or power stroke. With the volume of the chamber near its maximum, the chamber starts communicating with the exhaust manifold through the exhaust port. Further rotation of the power shaft reduces the volume of the chamber and expels the exhaust gas out of it. As the volume of the chamber gets near to its minimum, the chamber loses contact to the exhaust port and gets contact to the intake port to repeat the cycle.
In order to achieve wider variation of the angle between the two rotors, for instance from 60 to 120 degrees, it is necessary a wider angle between the toroidal cavity axis and the rotation axis of the power shaft, for instance 55 degrees.
This way the chambers become less “oversquare” and occupy a bigger percentage of the toroidal cavity volume.
Each combustion chamber is sealed by two rotating/oscillating pistons, the first secured on the first rotor, the second secured on the second rotor. The force on the first piston multiplied by the constant, and inevitably long, eccentricity of the first piston from the toroidal cavity axis is the torque that loads the first rotor shaft. A force of equal strength is applied on the second piston and creates an equal and opposite torque on the second rotor shaft. Besides the torque caused by the gas pressure, the rotor shaft carries also the inertia torque generated by the variable angular velocity of the rotor about the toroidal cavity axis.
The power shaft receives, from each of the two rotor shafts, a torque and passes their difference to the flywheel and then to the load.
The toroidal rotary engine has several advantages: simplicity, riddance of valves, four-cycle aspiration, compact and efficient combustion chamber, lightweight, compactness, smoothness etc.
Its Achilles' heel is the mechanism interconnecting the rotating/oscillating pistons to the power shaft.
The problem is that for equal piston diameters, the torque on the crankshaft of the conventional engine is way lower as compared to the torque on each rotor shaft of the toroidal rotary engine. This is because of the long, and constant, eccentricity of the piston of the toroidal rotary engine, making crucial the use of massive and robust “mechanism” between the power shaft and the rotor shafts. The two concentric Cardan joints that interconnect the power shaft with the two rotors are disposed out of the toroidal cavity, exclusively at one side of the toroidal cavity, so that the toroidal cavity poses no limits on their dimensions and strength, while the casing needs be strong only at the one side of the toroidal cavity. The yoke, or like-yoke, mechanism between a rotor and the oblique power shaft generates on the rotor a strong parasitic/idle moment, or thrusting pair of forces, on a plane containing the axis of the toroidal cavity. Without a strong rotor shaft of adequate length, it is quite difficult, if not impossible, to support such thrust moment. This is the case in arrangements like those proposed in U.S. Pat. No. 3,899,269, U.S. Pat. No. 2,253,445 and U.S. Pat. No. 4,949,688 comprising oblique power shaft passing through the center of the toroidal cavity. In these patents the interconnecting mechanism between the power shaft and the rotors is constrained into the limited space at the center of the toroid, hence being inevitably of limited strength. Also the fact that the inner edges of the toroidal cannot be directly bridged/secured to each other, make them incapable of receiving the strong bending moment generated by the interconnecting mechanism. It is like levering a lever between the teeth of two closed jaws. The limited strength of the interconnecting mechanism, the increased friction caused by the strong bending moments applied by the rotors on the toroidal cavity inner edges and the deformation of the toroidal cavity render such arrangements unsuccessful.
Besides the strength of the mechanism it is also the simplicity. In the present invention the number of the parts is kept at minimum: besides the power shaft and the two rotors met in the toroidal rotary engines of the art, all it takes is two “yokes”. In comparison, the arrangement proposed in U.S. Pat. No. 4,174,930 comprises, besides the parts of this invention, a differential-like gear box and other additional parts that increase the length, increase the friction and reduce the reliability. Similarly, the arrangement of U.S. Pat. No. 4,086,879 comprises two additional rotating shafts at the two sides of the toroidal cavity, and the engine casing needs to have strong structure at both sides of the toroidal cavity.
Unlike the conventional reciprocating engine, where the pistons are supported and guided by the cylinder wall, in the reciprocating piston engine of PCT/EP2007/050809 the pistons need not touch the walls, allowing the cross section of the cylinder bore being machined a little wider towards the ports, in order to reduce the sealing means friction and to improve the control over the lubricant by reducing the lubricant quantity that reaches the ports. Likewise in engines of this invention, since the pistons do not need to touch the toroidal cavity, the cavity can be machined with a wider cross section near the ports in order to optimize the pressing of the rings and to reduce the quantity of the lubricant that reaches the ports, especially at the overheated bridges of the exhaust ports and get burned or passes into the exhaust.
The drawings and the analysis make it clear that another principal problem of the motion converting mechanism of these engines is the heavier twisting moments, i.e. torques, the two rotor shafts and the crosses undergo. And whatever limits their dimensions make them unreliable.
In a second preferred embodiment, shown in
If the pivot axis is not perpendicular to the plane defined by the power shaft axis and the toroidal cavity axis, besides the variation of the compression ratio and of the displacement, the rotation of the toroidal cavity varies also the phase of the chamber relative to the ports and to the spark plug/injector.
The right angle between the two pivot axes of a yoke is not obligatory.
In a third preferred embodiment, shown in
The fluid, liquid or gaseous, is suctioned by two intake ports of the toroidal cavity, some 180 degrees away from each other, and is discharged under pressure through two discharge ports of the toroidal cavity, also some 180 degrees away from each other. The same pump may serve two separate circuits. For instance, if the pump is used as an artificial heart to pump the blood of a patient, blood from the body, poor in O2, is suctioned through the first intake port, this blood leaves the pump through the first discharge port to the lugs, blood from the lugs, rich in O2, is suctioned by the second intake port and leaves the pump, through the second discharge port, to the body under pressure.
In a fourth preferred embodiment, the pump of the third preferred embodiment is modified to a continuously variable capacity pump. The toroidal cavity of the pump is pivotally mounted on the casing of the pump at a pivot axis passing through the center of both Cardan joints. Changing the angle between the axis of the toroidal cavity and the axis of the power shaft, the capacity varies from zero to a maximum. If it is used as the oil pump for the lubrication of a reciprocating engine, the variable capacity controls the oil pressure at the desirable level, avoiding the energy loss in the waste/“relief valve” of the conventional oil pumps. The simplest control is a restoring spring between the casing and the toroidal cavity: at high volume the pressure tends to increase, the toroidal cavity presses heavier the restoring spring, the angle between the power shaft and the rotor shafts decreases and so the volume is reduced and the discharge pressure is kept within the desirable limits without a relief valve.
