Rotary expansible chamber devices – Intermittently accelerated and receding members rotate in... – Each a working member
Reexamination Certificate
1999-12-10
2002-04-16
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Intermittently accelerated and receding members rotate in...
Each a working member
C418S037000
Reexamination Certificate
active
06371743
ABSTRACT:
This invention relates to rotary internal combustion engines. This invention also relates to rotary positive displacement apparatus such as fluid pumps and engines that utilise a toroidal cylinder for the working chambers.
Such internal combustion engines, fluid driven motors, fluid pumps and external combustion engines are hereinafter collectively referred to as toroidal engines. However, for illustrative purposes this invention will be exemplified hereinafter by reference to its internal combustion engine application.
Many forms of rotary engines have been contemplated and manufactured. Mostly they have been proposed as a means of reducing the inherent disadvantages associated with conventional reciprocating piston engines, and/or with a view to providing a compact or lightweight engine which is economical to manufacture and fuel efficient. To date these have not been commercialised. The only internal combustion engines which are mass produced are the Wankel rotary engine and the conventional reciprocating piston engine.
Conventional reciprocating pumps and engines have been universally utilised due to their efficient and simple conversion of reciprocating motion of the pistons, to a rotary motion via a crankshaft. However, conventional reciprocating internal combustion engines have fuel consumption limitations imposed by friction due to the multiplicity of moving parts. These moving parts generally include the bearing journals where friction increases with the speed of rotation and the number of bearings, the piston rings that impose friction by the plurality of rings on each piston, and the valve train where numerous components operate as a combined system that contributes significant friction to the engine as a whole.
In addition, thermal efficiencies of reciprocating internal combustion engines are reduced by the design of the mechanical components, the materials used, the manner of operation and, the use of a common cylinder portion for all the cycle phases. Fuel efficient conventional reciprocating internal combustion engines do exist but are highly complex units. Such complexity increases manufacturing and assembly costs.
The Wankel engine has found application in motor vehicles because of its high performance potential. However, for various reasons it has not been utilised for general use as a replacement for conventional piston engines such as commuter vehicles or mass produced small industrial engines.
Other forms of rotary engines have also been proposed. These include toroidal engines having a toroidal cylinder formed in the cylinder housing about a driveshaft assembly, rotor means supported for rotation about the driveshaft and coupled to pistons in the toroidal shaped cylinder whereby the pistons move cyclically toward and away from one another forming expanding and contracting working chambers therebetween within the toroidal cylinder, and, inlet and outlet ports extending through the cylinder housing assembly for entry and exit of fluid to and from the working chambers.
Typical prior art of toroidal engines are outlined in “THE WANKEL ENGINE DESIGN DEVELOPMENT APPLICATIONS” by Jan P. Norbye published by the Chilton Book Company. French Patent No. 2498248 to Societe Nationale D'Etude et de Construction de Moteurs D'Aviation Snecma, and German patent No. 3521593 to Gebhard Hauser also illustrate prior art toroidal engines. Some of these engines utilise external mechanisms to effect the cyclic motion of the pistons, which move within the cylinder, while others utilise swash plates and cams and the like in the power train to achieve the desired mechanical coupling of the drive components.
For the purpose of mass production, it is considered that all this prior art has disadvantages either in inefficient configurations in terms of operation, or the ability to perform satisfactorily under normal working loads such as sustained optimum power delivery. Many of the prior proposals also require sophisticated manufacturing or assembly processes, are difficult to seal, are overly complex, or operate in an inefficient manner.
The present invention aims to provide toroidal engines which will alleviate at least one of the disadvantages outlined above.
With the foregoing in view, this invention in one aspect resides broadly in rotary positive displacement apparatus of the type having a toroidal cylinder formed in a cylinder housing assembly about a driveshaft with its axis concentric with the axis of the toroidal shaped cylinder and coupled to juxtaposed rotor assemblies having pistons in the toroidal shaped cylinder whereby rotation of the driveshaft rotates the rotors in a manner which causes the pistons to move cyclically toward and away from one another during their rotation, forming expanding and contracting working chambers therebetween within the toroidal cylinder and inlet and outlet port means extending through the cylinder housing assembly for entry and exit of fluid to and from the working chambers, and wherein the coupling means coupling the pistons in the toroidal shaped cylinder to the driveshaft includes:
drive means for coupling one rotor assembly to the driveshaft;
a crankpin offset from the driveshaft;
a planetary member driven for rotation about the crankpin at a predetermined rotational speed relative to the driveshaft whereby the planetary member is supported on the crankpin for epicyclic movement about the driveshaft, and
a direct drive connection between the other rotor assembly and the planetary member offset from their respective axes whereby the differential angular velocity of the direct drive connection about the driveshaft axis resultant from its epicyclic motion thereabout causes the pistons of the other rotor assembly to move cyclically toward and away from the pistons of the one rotor assembly as it rotates about the driveshaft.
The driveshaft may rotate in the same direction as the rotor assemblies but for most applications as an internal combustion engine it is preferred that the driveshaft is constrained to counter-rotate relative to the rotor assemblies whereby the speed of rotation of the rotor assemblies may be reduced relative to the speed of rotation of the driveshaft.
The drive means for rotating the planetary member about its orbiting axis may include a chain or toothed belt passing from a driven sprocket/pulley mounted on the planetary member concentric with the orbiting axis and about a drive sprocket/pulley mounted on the cylinder housing assembly. Alternatively the drive means may include a gear mounted on the planetary member and meshing internally or externally or indirectly through a gear train with a sun gear/annulus gear fixed to the cylinder housing assembly. Thus the planetary member may rotate with a planetary gear driven from a fixed sun gear co-axial with the driveshaft for rotating in the same direction as the rotor assemblies.
In the preferred form the planetary member rotates with a planetary gear driven from an annulus gear co-axial with the driveshaft whereby the driveshaft counter-rotates relative to the rotor assemblies.
The planetary member may be in the form of a lobed member constrained for epicyclic motion with respect to the driveshaft axis and cooperating directly with complementary lobes associated with the cylinder housing assembly. For example in an eight piston version the planetary member may be a six lobed member meshing externally with an eight lobed housing portion.
Preferably the driveshaft extends through the rotor assemblies and is mounted rotatably in bearings in the cylinder housing assembly at opposite sides of the rotor assemblies. The planetary member may be constrained for rotation about the driveshaft axis by being supported on a track formed in the support assembly and extending about the driveshaft, or on a crank type mounting rotatable about the driveshaft axis. Preferably however the driveshaft is in the form of a crankshaft forming the crankpin intermediate its mountings in the cylinder housing assembly and the planetary member is supported on the offset crankpin. Furthermo
Holland & Knight LLP
Vrablik John J.
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