ABSTRACT
?A Patented new power machine concept has been designed and analyzed for production, and proof of principle sub scale tests have been performed, with positive result. The machine design concept is applicable as a compressor, pump, motor, or engine. Simplicity of design based on spherical ball piston enable a low moving part count, high power to weight ratio, elimination of valve train and water cooling systems, and perfect dynamic balance.
The new design concept utilizes novel kinematic design to completely eliminate inertial loads that would contribute to sliding friction. Also, low leakage is maintained without piston rings by using a small clearance on the ball piston, resulting in choked flow past the ball. These features provide the potential for an engine with higher efficiency than conventional piston engines. The engine design - utilizes existing recent technology to advantage, such as silicon nitride ball pistons, so a large development effort is not required.
INTRODUCTION
????????? The ball piston engine is a new concept in high efficiency power machine. Although the basic geometry was invented by individuals, the concept has been subsequently studied and developed by scientists and professional engineers.
The machine concept is attributes to simplicity. Having only a small number of moving parts, the design implements a modified version of the tried and proven thermodynamic otto cycle when use as a engine. Although the small parts count an important advantages, other than the ball piston engine will give future engineers new- found freedom in tailoring the combustion processes.
TYPES OF ENGINE
CONSTRUCTION OF MULTI ENERGY DOMAIN ENGINE (MULTISTROKE ROTARY BALL PISTON ENGINE MODLE)
A multi energy domain engine stimulation model was developed for efficiency studies. The model was based on the equation of motion (1). Approximate models working gas thermodynamics, coulomb friction and ball piston leakage were include.
The multienergy (multi cylinder) domain engine consist of the number up to 8to12 in which the ball piston enclosed each cylinder
WORKING OF MULTIENERGY DOMAIN BALL PISTON ENGINE
The basis of the design is ball pistons rolling on an eccentric track. The balls exert tangential force on the cylinder walls which turn the rotor. Useful power is available at the rotor output shaft. The combustion chambers are within the spinning rotor. Chamberporting for intake, compression, power, and exhaust strokes is achieved by passage of the chamber tops across an internal stator with appropriate feeds as the rotor spins.??????
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Beginning at top dead center (TDC) at 0 degrees rotation, the stator intake passage is open to the ?cylinder and a fuel/air charge is pulled into the cylinder as the ball piston moves radially outward? for the first 90 degrees of rotation (intake stroke).???????????????????????????????
Then the intake passage is closed off, and the ball reverses radial direction for the next 90 of degrees of rotation, during which time the new charge is compressed (compression stroke). Just past 180 degrees rotation, the compressed charge is ignited as the cylinder port passes a small ignitor port. Combustion ensues, and the high combustion pressure pushes radially outward???? (on the ball piston for the next 90 degrees of rotation. The ball in turn pushes tangentially on the cylinder wall because of the "slope" of the eccentric ball track, which is now allowing the ball to move radially outward. The tangential force produces useful torque on the rotor (power stroke).?
Fig.3 Compressions and Suction Stroke
At 270 degrees of rotation, the spent combustion charge is allowed to escape through the exhaust passage as the cylinder port is uncovered. Exhaust is expelled as the ball moves radially inward for the next 90 degrees of rotation (exhaust stroke). Then the cycle repeats.
IMPORTANT DESIGN FUTURES
CONSTRUCTION OF WANKLE TWO STROKE ROTATY BALL PISTON ENGINE
The basic components of this engine are as
1 - rotary piston |
? 2 - rotary cylinder |
? 3 - housing |
? 4 - spherical combustion chamber |
? 6 - inlet |
? 7 - exhaust |
? 8 - air intake |
? 9 - rotary cooling fins |
10 - air outlet |
12 - dividing wall |
15 - piston ball bearing |
16 - working chamber |
Fig.4 Drawing taken from German Patent Specification 2519911 and GDR-Patent 113788
The principle components of this engine are two rotors: (1), an inner piston rotor turning within (2), an external cylinder rotor, with both set at oblique axial angles to one another. The piston rotor is a sphere, from which a section resembling the shape of an orange wedge has been removed and which rotates around two ball bearings, (15). The cylinder rotor is a hollow sphere of proportionate size enclosing the piston rotor. Both rotors turn in concert at the same speed. Only their rotational axes are at an angle to one another. For the spherical piston to be able to swivel inside the hollow sphere/cylinder, both rotational axes must intersect exactly in the center of the sphere. (This must be duly observed when constructing such an engine, as otherwise reactive forces would be generated between the piston and the cylinder.) If no errors have been made, the piston and cylinder turn freely within one another without contact and without exerting unnecessary forces on one another (apart from utilizable torque).? The cylinder rotor is seated at both ends in a stationary housing, (3) and possesses a shaft, (14). The cylinder rotor separates lengthwise into two halves, allowing it to be placed over the piston. Between these two halves, a dividing wall, (12) is also screwed in, turning the sphere into two hemispheres. The piston rotor has a corresponding cutout in the shape of an orange wedge, so that it can accommodate this wall. In between, two symmetrical working chambers, (16) are formed. (The whole unit resembles a joint for coupling two non-aligned shafts. The dividing wall connects the two rotors in a torque-proof fashion.)
?????????WORKING OF WANKLE ENGINE
????????? A spherical piston rotates in combination with a spherical housing, whereby the rotational axes alone incline towards each other slightly, not unlike a cardan joint. In the process, ?strokes? are created within the rotational system, which are employed to produce periodic volumetric change in working chambers. Two such symmetrical working chambers arise in diametrically opposing sides of the spherical piston, in sections cut out of the sphere like wedges removed from an orange, one on each side of a smooth dividing wall that extends into these areas and which is firmly anchored to the casing (external cylinder) that also rotates as part of the system.
In order to understand what goes on inside this device, we will have to take a look at the rotating system. Try to imagine yourself rotating along with the cylinder rotor. You will observe a swiveling or tumbling motion of the sphere-shaped piston in the sphere-shaped cylinder. The piston moves back and forth at periodic intervals right up to the dividing wall, while simultaneously swiveling lengthwise to it. It carries out a tumbling motion that can be differentiated into two pivotal motions occurring vertically on top of one another. One of these creates the desired stroke motion in the rotating system, the other enables asymmetrical timing. This engine has the kinematics of a single-rotational engine with the centers of gravity of both rotating parts are at rest. In the coordinate system at rest there are, in the case of this engine, no to and fro motions. The stroke motions exist only in the co-rotating, body-fixed coordinate system and generate no oscillating inertial forces. Consequently, this engine produces no vibrations resulting from oscillating inertial forces. (Consideration of the sealing components is for the time being left aside as this would go beyond the scope here of general descriptive purposes.)
Two rotors turn, one nested in the other. Contact between the two occurs via the sealing components. The sliding speeds arising through the motion of both parts tumbling in opposing directions in the co-rotating system are in fact low. Accordingly, high revolutions per minute are possible (more than 20,000 rpm). Centrifugal and other inertial forces are however present and may affect particularsealing components at very high speeds.
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? Fig.5 This was the first model??????????????
Operation and Timing OF WANKLE TWO STROKE ROTARY BALL PISTON ENGINE
The drawing refers to a normal two-stroke process, i.e., one working chamber functions as the charge pump, the other as the engine. Air reaches the charge pump after passing through a port, (6), and is then compressed into the side of the engine via ducts (not visible) - after the outlet, (7) has been closed by the piston and piston rings. Through the swiveling motion of the top edge of the piston this is achieved easily, with the engine developing asymmetrical timing as a result, similar to that of a standard four-stroke engine. This is a great advantage over a normal two-stroke engine. The gas is then fired in the sphere-shaped combustion chamber, (4). Near the bottom dead center, the outlet is again opened and then shut again, then the cycle,,,, takes place, and so on.
The ignition voltage is transferred here through non-contact, which is unproblematic. (On the contrary, it increases the effectiveness of the spark plug.) By virtue of the better timing diagram and the significantly higher volumetric efficiency ? the ?crankcase pump? here having almost no dead volume ? a single combustion stroke here produces more power than is the case with a standard two-stroke engine, for which reason the engine output per unit of displacement here is higher.? Moreover, the number of revolutions per minute can be increased even more, the bearings not being subject to the otherwise high inertial forces, which in turn raises the engine output per unit of displacement. It would thus be not only a prime mover for lawnmowers and standard motorcycles and cars, but also a high-performance engine for racing drivers.
For standard cars, the engaging/disengaging of individual cylinders would be more easily achievable, since they are anyway connected to each other via cogs, gear wheels or similar means.
Other operations corresponding more to those of a turbine would also be feasible.
The rotary piston apparatus could also serve as a compressor. It would be less suited for work as a pump, however, since it would have the same high pulsation rates as a typical two-cylinder piston pump.
Fig. 6 Different positions of the piston
(The wall etc are removed)
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LUBRICATIONS AND COOLING OF ENGINE
Lubrication ?
As is the case with a standard four-stroke engine, an oil bath is situated behind the piston, which in turn is fitted with oil scraper rings. Here, attention must merely be paid to ensuring that the oil gathers externally, because of the rotation. In fact, if outlet ports are placed in this area for the oil, an oil pump can be potentially dispensed with. Otherwise, oil that is pumped into the center also carries heat from the interior to the exterior, which in turn can be utilized for cooling purposes.
Cooling
Plain and simple forced air lends itself as a cooling system here. There are cooling fins attached to the outside of the cylinder rotor that simultaneously act as fan blades. Cooling air is sucked in at the rear and through channels, (8) inside and blown out through holes, (10) in the housing, (3). (An oil circulation system could also be brought in for cooling purposes.) A water-cooling system would not be so easy to bring about, but would also be feasible. The manner of cooling depends on whether the intention is to use the engine to power a lawnmower or a racing car.
ADVANTAGES OF ROTARY BALL PISTON ENGINE
DISADVANTAGES
APPLICATION OF ROTORY BALL PISTON ENGINE
The wankle advanced two stroke ball piston engine can be applied to land mover, standard motor cycle and car and also for racing car.
CONCLUSION
????????? From analysis the design assumptions show that the ball piston engine has potential for achieving higher efficiency than piston internal combustion engine. Having only small moving parts and achieving higher efficiency.
A new approach to kinematics design has devised to eliminate friction contribution from internal forces in the engine. On the other hand, conventional carburetion/induction and exhaust system are applicable to the new engine.
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