Internal-combustion engines – Free piston – Single chamber; one piston
Reexamination Certificate
2000-02-09
2002-02-26
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Free piston
Single chamber; one piston
C123S0460SC
Reexamination Certificate
active
06349682
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
This invention is in the field of propulsive machines cooperating with internal combustion, free piston engines and compressors to produce motive power, lifting, or other uses. This invention also relates to a self-actuated fuel injector that may be utilized in such an engine.
Background of the Invention
Numerous inventions known in the prior art have been developed, and many proposed which are based on the Newtonian principle of reactive propulsion. Propellers and helicopter rotors, jet engines, and rockets are the principal examples of that genre.
Propellers and rotors, however, require complex internal combustion or gas turbine engines to supply rotating torque to airfoil shaped blades. Large amounts of unconstrained, low pressure air is propelled aftward of the propeller/rotor due to the lift and screw action of the airfoil shaped blades, creating thrust and invoking the concomitant slip, drag, and kinetic energy air stream losses. The total fuel efficiency of these systems is determined primarily by the engine and propeller inefficiencies. In the present invention, there are no propeller losses, and engine losses and engine weight are minimized by the elimination of piston rods, crankshafts, flywheels, transmissions, and, in the case of turbines, high soak temperature turbine blading, adjunct compressors, and internal flow losses.
Chemical thermal-jet engines utilize ram air and axial flow or centrifugal compressors to force air into an engine inlet and raise its pressure in a combustion chamber. In the combustion chamber, fuel is injected and burned creating high temperature, high velocity gases. Part of the gas velocity energy is used up driving turbine blades for the compressor, and the gas then exits a nozzle to produce thrust. Large thermal losses are incurred due to the extreme temperatures at which the jet engine must operate. Rocket engines carry fuel and oxidizer internally and generate their propulsive gasses from within.
Free piston internal combustion engine and compressor combinations are well known, and the prior art contains many examples of various concepts and configurations. None were found which incorporates a power stroke at each end of a single cylinder and uses an unadorned, simple piston whose only functions are to separate the combustion and compression chambers and provide inertial energy storage. Free piston engines and compressors disclosed in the literature are complex and heavy devices which go to great lengths to counteract cylinder reaction to the acceleration of the piston(s) by the use of elaborate spring-counterweight mechanisms or tandem pistons synchronized by rack and pinions, linkages, gears, or other mechanical means.
However, there are no feasible, chambered high pressure propulsion systems that utilize unheated atmospheric air, on a continuous basis, as the main propellant medium. The reason for this is undoubtedly the difficulty of conceiving an engine and compressor combination that is simple and lightweight enough to make it practical.
SUMMARY OF THE INVENTION
The present invention involves a major change in the concept of vertical lifting and locomotion in each of the primary modes of land, air, and marine propulsion. As a necessary prerequisite to invention of the atmospheric propulsion engine, the unicycle free piston engine was invented as described herein. The combination of atmospheric air propellant and unicycle free piston engine are part of the unique and defining elements of the present invention.
The single cycle free piston engine disclosed herein uses a simple lightweight piston which minimizes the reactive movement of the cylinder assembly (this movement being a function of the ratio of piston mass-to-cylinder assembly mass).
This present invention is an atmospheric propulsion engine, firing its free piston at each end of the cylinder, scavenging of exhaust products, and natural self cooling due to the large internal ingestion of atmospheric air.
As an indication of the efficacy of the atmospheric propulsion engine, a simple calculation is presented. A cylinder 1.5 inches in diameter, and 18 inches long contains a volume of 31.8 in
2
and has a weight of air equal to 0.0014 lbs. at standard atmospheric conditions. When this mass of air is expelled at 70° F. (520° R), at sonic velocity, in 0.010 seconds through a thrust-producing nozzle, a force of 4.83 lbs. is generated. If this same mass of air is expelled at the temperature and pressure corresponding to a 10 to 1 compression ratio (1300° R and 370 psi), the force generated would be 7.71 lbs.
The atmospheric propulsion engine will produce a thrust (force) somewhere between the above numbers, and a computer simulation of the above configuration indicates that an average thrust of 6.4 lbs. can be achieved. Using aircraft type construction, it is estimated that such a device would weigh about 2.1 lbs., yielding an engine thrust-to-weight ratio of 3-to-1. Based on this evaluation, the atmospheric propulsion engine would be suitable for flying and hovering applications, as well as numerous other uses discussed in the following descriptions.
Note: The above performance calculations are based on the following formulas:
Sonic
velocity
=
k
×
g
×
R
×
T
Where:
k=Ratio of specific heat for air=1.4
g=Gravity constant=386.4 in./sec
2
R=Gas Constant=640 in-lb/lb-° F.
T=Temperature ° R
The specific impulse of the above configuration is calculated to be in the 2000 to 4000 lb-sec/lb range using standard automotive gasoline or diesel fuel.
A comparison of existing art with the present invention of the atmospheric propulsion engine reveals the superior characteristics of the concept and method.
This invention directly converts the fuel's thermal energy primarily into mechanical Pressure/Volume (PV) forces, compressing atmospheric air and expelling it at sonic velocity to efficiently generate thrust. The only major moving part in the atmospheric propulsion engine system is the internally shared engine/compressor piston which presents another major advantage of this invention, especially in the case of helicopters, by the elimination of noisy and dangerous external rotating propellers and rotor blades.
In the present invention, most of the fuel's thermal energy is used up in the PV expansion process of the working fluid to drive the piston, thus, after the compressed air propellant is expanded in the thrust nozzles, a relatively cool, benign gas is expelled. No compressor is required as atmospheric pressure is adequate to refill the expulsion gas chamber. However, superchargers, or in applications involving moving vehicles, ram air, can be utilized to raise the compressor inlet pressure, thus enhancing compressor volumetric efficiency and increasing the engine's thrust-to-weight ratio.
Applications for an independent, free standing thrust engine are manifest.
Given a nominal engine thrust to weight ratio of 3 to 1, coupled with the benignity of the exhaust products, it becomes feasible to design and market a personal passenger vehicle which can fly to its destination without having to concern itself with roads, bridges, or other ground based obstacles. This thrust to weight ratio also may make the engine applicable to “backpack” individual flying machines. Steering, stability and control of such flying machines can be accomplished through thrust vector control mechanisms such as movable nozzles or jet vanes as shown in
FIGS. 10 and 11
, or may be implemented by other well known aerodynamic means available in the existing art.
Much effort has been expended in the quest for reducing weight and increasing the efficiency of automobiles to combat air pollution. An automobile designed using the lightweight atmospheric propulsion engine disclosed herein would preclude the necessity for flywheels, crankshafts, piston rods, cooling systems, transmissions, driveshafts, differentials, and drive axles. This would eliminate the weight, power loss
Alexius Karl R.
Alexius Renee S.
Alexius Richard C.
Alexius Karl R.
Alexius Renee S.
Benton Jason
McMahon Marguerite
LandOfFree
Free piston engine and self-actuated fuel injector therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Free piston engine and self-actuated fuel injector therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Free piston engine and self-actuated fuel injector therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2979787