1. Field of Invention
Internal Combustion engines have been in use for over one hundred years. In the case of common gas and diesel engines, it is known that between 20-25% of fuel power is lost due to the friction force between the piston and the cylinder; this is particularly more evident while the engine is under significant mechanical load. The share of loss due to friction between the piston rings and the cylinder is approximately 3% of fuel power. The reason for the high loss of power due to friction between the piston and the cylinder is the large force which acts on the piston rod. That force has a component perpendicular to cylinder inside wall. Although there are other frictional losses in internal combustion engines, but the said friction between the piston and cylinder is the major frictional loss. Reduction of said friction force will cause greater efficiencies than that of normal engines.
On the combustion side, for enhancing the engine performance and efficiency, the ability to change the compression ratio, although not a vitality, has received more attention in recent years.
As far as enhancement of combustion and engine efficiency is concerned, this disclosure will be addressing these two concepts.
The principal objective of this invention is to introduce a new method of drastically reducing the friction force between the piston and the cylinder. In that regard the invention will introduce support mechanisms for piston rods with one degree of freedom and will expand on the concept of piston rod support for the piston rods and crank cams which are introduced in “Behnam Reciprocating Mechanisms”, B. Nedaie, U.S. pending patent application Ser. No. 13/482,993. Furthermore this disclosure shows how the same principle could be applied for piston rods connecting to ordinary crankshafts. For a piston rod with only translational motion, a special connection between the piston and piston rod will be illustrated. In addition to that in order to enhance combustion, a method of changing the compression ratio will be presented.
The disclosure shall be presented by the aid of the following figures:
a shows a three dimensional model of the apparatus said in
a shows a three dimensional model of the apparatus said in
b shows the geometrical-conceptual illustration of an apparatus for a piston rod being supported by moving cylindrical rollers while the piston is at top dead center position.
c shows the apparatus said in
d shows the isometric view of an apparatus for supporting the piston rod with moving rollers in which the piston rod and the moving rollers are furnished with gear teeth.
e shows the apparatus said in
f shows section A-A from
g shows section A-A shown said in
h shows front elevation view of the apparatus said in
j shows section B-B shown from
i shows section B-B shown in
a shows an apparatus for special connection of piston and piston rod such that the piston can have minute movements with respect to the piston rod in any direction perpendicular to the piston central axis.
b shows the point of connection of piston and piston rod said in
c shows section C-C from
d shows the apparatus said in
Drastic reduction of friction force between the cylinder and the piston:
Considering an ordinary internal combustion engine, as said before the loss of power due to friction between the piston and the cylinder accounts for a large portion of power produced by the fuel. In engines with ordinary crankshafts, the said friction force is directly proportional to the coefficient of friction between the cylinder and the piston, and the normal component of the force (normal to cylinder wall) by which the piston and the piston rod exert against each other. This is because the same force will be exerted by the piston to the cylinder. The said friction force is variable throughout the duration of each stroke mainly because the pressure inside the cylinder chamber changes during a stroke; additionally the piston rod has two degrees of freedom: translation and rotation. Due to the said rotation the magnitude of the said friction force changes as the angle of piston rod with respect to piston central axis changes.
For a cam engine which has a piston rod with one degree of motion and in particular an engine with a crank cam suggested in “Behnam Reciprocating Mechanisms”, (U.S. pending patent Ser. No. 13/482,993 by B. Nedaie), the piston rod which is directly connected to the piston, has only one degree of freedom and that degree of freedom is translation along the cylinder's central axis. As a result if the piston rod is supported by roller bearings, the friction force between piston and cylinder will be almost eliminated. The two
The piston rod 1 (the piston and piston rod could be one solid piece) is supported by roller bearings 2 which are held by the stationary support 3; the assembly of the stationary support 3 and the roller bearings 2 (in this case 6 roller bearings) is shown by numeral 2A (numeral 2A is shown in a simple presentation to illustrate the concept). Said numeral 2A is fixed to the engine block (engine block not shown); also the crankshaft's central shaft is mounted as normally a crankshaft is held in the engine block. The piston rod 1 must have flat surfaces where it is in contact with the roller bearings 2. As a result of the geometry of this apparatus, the piston does not exert a significant force against the cylinder and the said force will be reduced drastically. The number of roller bearings on either side of piston rod 1 must be at least two. In the apparatus shown in
Referring to
For both apparatuses shown in
The same result might be achieved with other similar arrangements. For example for each roller bearing, two ball bearings holding a roller could be used. Another scenario is supporting the piston rod from two directions instead of one direction as shown in this disclosure. But in mechanisms shown in
Since the forces acting on the stationary ball or roller bearings supporting the piston rod mentioned so far will be tremendous, particularly when the engine is under great mechanical load at high RPM, therefore as a result the size of these bearings might be so large that it might not be practical to implement stationary roller or ball bearings in practice. Therefore it is important to consider the option of supporting the piston rod with moving cylindrical rollers.
In
In order to use moving cylindrical rollers 21 for the purpose of supporting the piston rod 20, it must be realized that first of all the central axes of rotation of these moving rollers 21 must have no motion with respect to each other. That is during the operation of the engine the distance between each two rollers must remain the same at all times. Secondly there must be no slippage at the area of contact between the surfaces of the moving cylindrical roller 21 and the piston rod 20 and the stationary support 19a. Such slippages can severe the operation of the engine and additionally may result in frictional losses.
In order to address the said two points in the previous paragraph, each of the moving cylindrical rollers and the piston rod could be furnished with gear teeth.
The components and their function are as follows:
Piston 25: Piston 25 is inside the cylinder of engine block 27 and is connected to piston rod 26; the piston 25 and the piston rod 26 could be two separate pieces or one solid piece. Piston 25 has one degree of motion and that is translation along the central axis of the corresponding cylinder in engine block 27.
Piston rod 26: Piston rod 26 has only one degree of motion and that is translation along the central axis of the corresponding cylinder; unlike ordinary piston rods, it does not have any rotational motion. It is connected to piston 25 from one end and from the opposite end is connected to either a cam shaft as already shown in
Engine block 27: Engine block 27 is shown only partially in a simple way to address the features discussed in this invention; the stationary support 32 is fastened to the engine block 27 by nuts 33.
Triple pin 28: Triple pin 28 has three pins and each pin goes inside the hole of geared roller 30 such that the corresponding geared roller 30 is free to rotate about the central axis of the said pin. Triple pin 28 has one degree of freedom and that motion is translation along the direction of the central axis of the cylinder.
Flat end 29: The purpose of Flat end 29 is to secure geared rollers 30 and stop the geared rollers 30 from any translation motion along the direction of its axis of rotation. Flat end 29 has one degree of freedom and that motion is translation along the direction of the central axis of the cylinder.
Geared roller 30: The geared roller 30 has a hole along its central axis and is freely rotatable about its central axis and each geared roller 30 is freely rotating about of the pins of triple pin 28. It has a gear section at the center and two cylindrical surfaces on either side of the said geared section. The large force exerted by the piston rod 26 to geared roller 30 is transferred via this cylindrical section (and not the geared portion) of the geared roller 30 to the stationary support 32.
Geared roller assembly 31: The geared roller assembly is comprised of three geared rollers 30, a triple pin 28 and a flat end 29. However the minimum number of geared rollers needed for each assembly 31 is two geared roller 30. Each pin of the triple pin 28 holds one geared roller 30 and the said geared roller 30 is free to rotate about the central axis of the corresponding pin of the said triple pin 28. The flat end 29 secures the geared rollers 30 in place. In
Stationary support 32: the stationary support 32 is fastened to the engine block 27 by nuts 33 and has no motion with respect to engine block 27. Although in these illustrations the stationary support 32 is not furnished with gear teeth, however it is possible to do so.
Nuts 33: These nuts 33 allow adjustable fastening of Stationary support 32 to the engine block 27.
For all the mechanisms discussed so far, it must be noted that the illustrated piston rod support will have no or very little effect on the friction between the piston rings (rings are not shown in any of the figures) and the cylinder. That portion of friction loss due to friction between the piston rings and the cylinder may remain the same.
It is obvious that the concept for supporting the piston rod for reduction of the friction force between the piston and the cylinder will result in smaller than normal cooling system for cooling the engine block. That is the size of radiator and cooling system will be reduced drastically to the extent that in some cases only air cooling may suffice. This is because the major reason for an engine block to heat up is the contribution of the said friction force between the piston and cylinder and not the heat transfer from the combustion. Likewise because of drastic reduction of the friction between the piston and the cylinder, the size of the starter mechanism and the power required to start the engine will reduce considerably.
Special Connection of Piston to Piston Rod:
Due to the nature of the operation of a piston rod with only one degree of freedom (that degree of freedom being translation along the direction of pistons central axis), there might be a need for a special connection between the piston and the piston rod. In that regard reference will be made to
Ideally there are three center lines which must be aligned. One is the central axis of the cylinder (the cylinder is not shown in these four figures); the second is the central axis of the piston 17 (numeral 17a) and the third is the centerline of the piston rod 16 (numeral 16a). In
This is because in the case of a piston rod with one degree of motion, if the connection of the piston to piston rod is a normal connection as it is in ordinary engines, manufacturing defects may cause large forces acting on the piston in the direction perpendicular to the piston axis and force the piston against the cylinder wall. In fact it was one of the main intentions of the invention to eliminate the force which the piston exerts to the cylinder. It is important that the piston must move in the cylinder as freely as possible in order to eliminate the associated frictional force.
In
Variable Compression Ratio:
This disclosure suggests that in order to change the compression ratio for a given internal combustion engine, an insert could be pushed into or pulled out of the cylinder head in order to control the compression ratio.
In
It is not the intention of this invention to address the methods of moving the compression ratio insert 9 into and out of the cylinder chamber; that might be achieved by mechanical, hydraulic or electrical servo motor mechanisms with appropriate controls. Nor is the intention of the invention to suggest any means or methods of control of the said action as to how often it must happen or for how long the insert 9 must stay at a certain position. It is primarily the methodology of changing the compression ratio which is under consideration.
In the figures shown in this disclosure, in each figure some parts might have not been shown and/or numbered; this is because only the concepts under consideration were to be addressed. As a result a detailed presentation of the internal combustion engine in these figures was avoided since it was not necessary.
The description given in this disclosure, it is obvious that the same may be varied in many other similar ways and methods. Such variations are not to be considered as departure from the core philosophy of the invented mechanisms. All such variations and modifications which are obvious to those skilled in the art are considered to be within the scope of this disclosure and embodied in the claims made.
| Number | Date | Country | |
|---|---|---|---|
| 61881429 | Sep 2013 | US |