The Ball Piston Engine

THE BALL PISTON ENGINE

CONTENTSCONTENTS

01 ABSTRACT

02 INTRODUCTION

03 TYPES OF ENGINE

04 CONSTRUCTION OF MULTI ENERGY

DOMAIN ENGINE

05 WORKING

06 IMPORTANT DESIGN FUTURES

07 CONSTRUCTION OF WANKLE TWO

STROKE ROTATY BALL PISTON ENGINE

08 WORKING

09 OPERATION AND TIMING

10 LUBRICATIONS AND COOLING OF ENGINE

11 ADVANTAGES & DISADVANTAGES

12 APPLICATION

13 CONCLUSION

14 REFERENCES

G. P. WASHIM PAGE NO.1


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

A multienergy domain engine (model)

Wankle to stroke rotary ball piston 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


Fig. 1 End section view of engine design


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. Chamber porting 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.

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


Fig. 2 Site Exploited view of engine design


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

The porting required for four stroke operation is achieved with

numbers of additional part, and no valve train losses. The porting

mechanism is achieved with simple port clocking within the

rotor/internal stator bearing interface. Thus part count is low and

hardware is simple in geometry, with only the rotor and ball piston as

moving part.

Sliding friction site are minimized by the use of a rolling ball piston.

Sliding friction still exists at the ball/cylinder wall contact, but it

minimized by special material selection and possibly local lubrication.

The use of an eccentric ball track allows tailoring of the chamber

volume vs time to optimize the cycle from a thermodynamic and

chemical kinetics stand point. The only requirement is that the ball

return to the starting radius at TDC before intake. For example

expansion/exhaust stroke length can be made different than for

intake/compression for more exhaust energy recovery, or the

combustion can be held at constant volume for a certain period.

Multicylinder rotor can be implemented. Instead of 4 stroke, 8,12 or

more stroke can be transverse in a single revolution. This effectively

multiplies the power out put proportionally if the stroke is maintain

constant.

The use of many ball pistons, which undergo the four strokes in

clocked fashion, result in smooth power delivery and small net

oscillatory forces, the total ball inertial forces are automatically

balanced by symmetry if numbers of ball is even.



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 particular sealing components at very high speeds.

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)



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

The ball piston engine (multi energy domain engine) having small

number of moving parts, the design implement a modified version

of the tried and proven thermodynamic otto cycle when use as a

engine.

It will give the future engineers new found freedom in tailoring the

combustion process.

The stroke magnitude and rate can be different for different stroke

in cycle (i.e. intake, compression, power and exhaust) so that it

provides the possibility of converting more energy to the shaft

power by greater expansion during the power stroke.

It has ability (i.e. in multi energy domain engine) to complete any

even numbers of strokes per revolution in single rotation of rotor.

This effectively multiplies the power output proportionally if

stroke is maintain constant.

In this engine the frictional losses are low and independent of

operating speed in contrast to conventional piston engine.

DISADVANTAGES

Leakage through the ball piston/cylinder gap is a significant

factor for engine efficiency at low speed.

Flow is choked during combustion due to high pressure

differential and small clearance area.



The friction and wear at the ball piston/cylinder wall sliding

interface.

APPLICATION OF ROTORY BALL PISTON ENGINE

It can be applied compressor.

The multi cylinder ball piston engine can be applied to pump,

motor.

It can be applied to 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.



REFERENCES

www.google.com

www.howstuffwork.com

www.wikepedia.com

www.ballpiston.com


http://www.ballpiston.com/

http://www.howstuffwork.com/

http://www.google.com/

The Ball Piston Engine

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