阅读说明：本技术 一种高密封性的类椭圆转子发动机 (High-sealing quasi-elliptical rotor engine ) 是由 蒋崇文 皮思源 许晨豪 李志豪 高振勋 李椿萱 于 2020-04-22 设计创作，主要内容包括：本发明公开了一种高密封性的类椭圆转子发动机,包括上端盖、下端盖,转子,三个燃烧腔,三段隔离带,喷油点火装置、密封销列和偏心驱动轴。本发明的技术方案,对转子与缸体型线提出了新的设计方案,在此基础上引入密封销列对不同燃烧腔之间的过渡区进行密封。本发明的发动机能较好地防止结构磨损效应,有效增强燃烧腔之间的密封性,减轻缸体之间的燃气泄露；设计的型线与密封方式能增大发动机的设计误差裕度,降低发动机的加工难度,从而有效降低发动机的生产成本。(The invention discloses a high-sealing elliptical rotor-like engine which comprises an upper end cover, a lower end cover, a rotor, three combustion chambers, three sections of isolation belts, an oil injection ignition device, a sealing pin array and an eccentric driving shaft. According to the technical scheme, a new design scheme is provided for the molded line of the rotor and the cylinder body, and a sealing pin array is introduced to seal transition areas among different combustion chambers. The engine can better prevent the structural wear effect, effectively enhance the sealing performance between combustion chambers and reduce the gas leakage between cylinder bodies; the designed molded lines and the sealing mode can increase the design error margin of the engine and reduce the processing difficulty of the engine, thereby effectively reducing the production cost of the engine.)

1. A high-sealing elliptical rotor-like engine is characterized by comprising an upper end cover (1), a lower end cover (2), a rotor (3), three combustion chambers (4), three sections of isolation belts (6), an oil injection ignition device (5), a sealing pin array (7) and an eccentric driving shaft (8),

the upper end cover (1) is connected with the lower end cover (2) through a screw (9) to form a cylinder body of the engine;

the hollow cavity in the cylinder body is a working cavity for the work of an engine and is used for the rotation of the rotor (3) and the thermodynamic cycle of the three combustion cavities (4), and the working state in the working cavity is determined by the molded line of the cylinder body and the molded line of the rotor (3);

the overall profile of the cylinder body molded line is triangular, three protruding inward concave cavities are uniformly distributed around the cylinder body for one circle to form three combustion cavities (4), the cylinder body molded line is formed by wall curves of the three combustion cavities (4) and curves of the three sections of isolation belts (6), and the wall curves of the three combustion cavities (4) and the curves of the three sections of isolation belts (6) are distributed in a staggered mode around the cylinder body for one circle, so that the cylinder body molded line is in 120-degree rotational symmetry;

the overall profile of the rotor (3) is elliptical, and a central hollow hole of the rotor (3) is connected with a central hollow hole of the upper end cover (1) and a central hollow hole of the lower end cover (2) through the eccentric driving shaft (8); the oil injection ignition devices (5) are arranged at the tops of the three combustion chambers (4) and are used for oil injection and ignition;

when the engine works, the rotor (3) is restrained to do planetary gear motion through the eccentric driving shaft (8) and the cylinder body profile, the rotor (3) rotates to form compression-expansion periodic motion in the three combustion chambers (4), the compression-expansion motion is circulated twice when the rotor (3) rotates for one circle, separate thermodynamic cycles are formed in the three combustion chambers (4) and drive the rotor (3) to rotate together, and useful work is output outwards through the eccentric driving shaft (8);

the sealing device is characterized in that sealing pin rows (7) formed by at least four sealing pins are equidistantly arranged on the three sections of isolation belts (6), the sealing pins are installed in pin holes in the three sections of isolation belts (6), sliding grooves (10) are installed on the inner walls of the pin holes, the sealing pins can slide through the sliding grooves (10), the sliding range is limited through stop blocks at the ends of the sliding grooves (10), the bottoms of the sealing pins are connected with the bottoms of the pin holes through springs (11), arc-shaped sliding sealing pieces (12) are installed at the heads of the sealing pins, and in the rotating process of the rotor (3), the sealing pin rows (7) are constantly contacted with the side walls of the rotor (3) and stably seal and isolate areas on two sides of the sealing pin rows (7) through the sliding sealing pieces (12).

2. The elliptical rotor-like engine with high sealing performance as claimed in claim 1, characterized in that the curves of the three-section isolation belt (6) are all circular arc curves, and the parameter equation is as follows:

wherein m is the number of the isolation belt, the value range is 1-3, and three sections of isolation belt curves are respectively represented; t is a variation parameter, and the value range is [ -1.0,1.0 ]; k is a cylinder shape coefficient, and the value range is 10.0-12.0; e is the eccentricity of the eccentric column on the eccentric driving shaft, and the value range is 0.005 m-0.007 m; q is a three-section isolation belt shape parameter, represents the ratio of the curvature radius of the isolation belt to the eccentricity of an eccentric column on the eccentric driving shaft, and has a value range of 3.0-6.0;

the wall surface curves of the three sections of combustion chambers (4) are in smooth transition at the intersection with the curves of the three sections of isolation belts (6), and the parameter equation of the wall surface curves of the three sections of combustion chambers (4) is as follows:

wherein theta is a variation parameter and the value range isAndrespectively three sections of wall surface curves of the combustion cavity (4);

corresponding to the cylinder profile, the parameter equation of the rotor (3) curve is as follows:

wherein alpha is a variation parameter, the numeric area is [0,2 pi ], and beta is the rotation angle of the rotor (3);

when the rotor (3) rotates along the rule of the equation, the motion of the rotor is planetary gear motion, no matter the angle to which the rotor (3) rotates, the curve of the rotor (3) and the molded line of the cylinder body are in a tangent state, the tangent points constantly fall on the curves of the three sections of isolation belts (6), and adjacent combustion chambers (4) are isolated from each other through the tangent points falling on the isolation belts (6) in the middle of the adjacent combustion chambers.

3. A highly sealed elliptical rotor-like engine according to claim 1 or 2, characterized in that on the seal pin action line, the distance between the intersection of the block profile with the seal pin action line and the intersection of the rotor (3) profile with the seal pin action line is the effective distance between the seal pin and the rotor (3); if the distance between the rotor (3) and the seal pin is smaller than the effective distance, the seal pin is in contact with the side face of the rotor (3), and the seal pin is in a sealing state; if the distance between the rotor (3) and the seal pin is larger than the effective distance, the seal pin is not in contact with the side face of the rotor (3), and the seal pin is in an idle state.

Technical Field

The invention belongs to the technical field of engines, and particularly relates to an ellipse-like rotor engine capable of improving sealing performance.

Background

The rotor engine is an internal combustion engine with a novel structure appearing in 50 s of the 20 th century, and compared with a common reciprocating piston type internal combustion engine, the rotor engine has the advantages of small volume, high power-weight ratio, low vibration and noise and the like. The engine is a four-stroke engine, which is designed by taking a double-arc epicycloid as a cylinder profile and taking an inner envelope line thereof as a rotor profile, and drives a rotor to do planetary motion around a cylinder through gear engagement.

In order to ensure the sealing performance of the engine in the running process, three protruding sharp points on a triangular rotor of the traditional triangular rotor engine always perform high-speed rotation motion in a state of keeping close to the wall surface of a cylinder body. The seal pin on this part is subject to more severe wear as the service life increases. Furthermore, considering that a large pressure drop is easy to occur between adjacent cylinder blocks in the running process of the engine, the abrasion of the seal pin can cause that the adjacent cylinder blocks cannot be effectively isolated, and therefore the problem of gas leakage between the adjacent cylinder blocks of the engine is easy to cause. In addition, the rotor and cylinder profile of the wankel engine is complex in design, and the allowable machining error margin is small, so that the machining difficulty in actual production is greatly increased.

Another rotary engine solution, also called X engine, is proposed by the LiquidPiston company, whose overall structure is similar to the wankel engine, which is exchanged between the inside and the outside, and which is designed with a double-arc epicycloid as the rotor profile and its outer envelope as the cylinder profile, both still ensuring the planetary motion of the rotor through gear engagement. The rotor profile and the cylinder profile of the rotor engine are redesigned from the perspective of inside and outside exchange of the X engine, however, the scheme only exchanges the inside and outside sequence of the rotor profile and the cylinder profile, and the structure and the motion characteristics of the profile are not changed. Therefore, the scheme still has the problems of serious sealing abrasion, cylinder gas leakage, higher processing cost and the like.

In order to solve the above problems, it is necessary to design a rotary engine that prevents structural wear, reduces gas leakage, and reduces the manufacturing cost.

Disclosure of Invention

The invention provides a high-tightness ellipse-like rotary engine which is different from the existing rotary engine, the engine is provided with a new engine profile, and a new engine sealing mode is provided on the basis of profile change. Compared with the existing rotor engine, the rotor engine provided by the invention has better space sealing performance, can better prevent the structure of the engine from being worn, and effectively reduces the gas leakage phenomenon between adjacent combustion cylinders. In addition, the cylinder body molded line and the rotor molded line are simpler and easier to process, so that the processing cost of the engine is greatly reduced. The specific technical scheme of the invention is as follows:

a similar elliptical rotor engine with high sealing performance is characterized by comprising an upper end cover, a lower end cover, a rotor, three combustion chambers, three sections of isolation belts, an oil injection ignition device, a sealing pin array and an eccentric driving shaft, wherein,

the upper end cover and the lower end cover are connected through screws to form a cylinder body of the engine;

the hollow cavity in the cylinder body is a working cavity for the work of an engine and is used for the rotation of the rotor and the thermodynamic cycle of the three combustion cavities, and the working state in the working cavity is determined by the cylinder body molded line and the rotor molded line;

the overall profile of the cylinder body molded line is triangular, three protruding inner concave cavities are uniformly distributed around the cylinder body for one circle to form three combustion cavities, the cylinder body molded line is formed by three combustion cavity wall surface curves and three isolation belt curves, and the three combustion cavity wall surface curves and the three isolation belt curves are distributed in a staggered mode around the cylinder body for one circle, so that the cylinder body molded line is in 120-degree rotational symmetry;

the overall profile of the rotor is elliptical, and a central cavity of the rotor is connected with a central cavity of the upper end cover and a central cavity of the lower end cover through the eccentric driving shaft; the oil injection ignition devices are arranged at the tops of the three combustion chambers and are used for oil injection and ignition;

when the engine works, the rotor is restricted to do planetary gear motion through the eccentric driving shaft and the cylinder body molded line, the rotor rotates, compression-expansion periodic motion is formed in the three combustion chambers, the compression-expansion motion is circulated twice every revolution of the rotor, independent thermodynamic cycle is formed in the three combustion chambers, the rotors are driven to rotate together, and useful work is output outwards through the eccentric driving shaft;

the sealing device comprises three sections of isolation belts, sealing pins and a spring, wherein the three sections of isolation belts are equidistantly arranged to form sealing pin rows, the sealing pins are arranged in pin holes in the three sections of isolation belts, sliding grooves are formed in the inner walls of the pin holes, the sealing pins can slide through the sliding grooves, the sliding range is limited through a stop block at the end of the sliding grooves, the bottoms of the sealing pins are connected with the bottoms of the pin holes through the spring, arc-shaped sliding sealing pieces are arranged at the heads of the sealing pins, the sealing pin rows are constantly contacted with the side wall of the rotor in the rotating process of the rotor, and areas on two sides of the sealing pin rows are stably sealed and isolated through the sliding.

Furthermore, the curves of the three isolation belts are all circular arc curves, and the parameter equation is as follows:

wherein m is the number of the isolation belt, the value range is 1-3, and three sections of isolation belt curves are respectively represented; t is a variation parameter, and the value range is [ -1.0,1.0 ]; k is a cylinder shape coefficient, and the value range is 10.0-12.0; e is the eccentricity of the eccentric column on the eccentric driving shaft, and the value range is 0.005 m-0.007 m; q is a three-section isolation belt shape parameter, represents the ratio of the curvature radius of the isolation belt to the eccentricity of an eccentric column on the eccentric driving shaft, and has a value range of 3.0-6.0;

the wall surface curves of the three sections of combustion chambers are in smooth transition at the intersection parts with the curves of the three sections of isolation belts, and the parameter equation of the wall surface curves of the three sections of combustion chambers is as follows:

wherein theta is a variation parameter and the value range isAndrespectively three sections of combustion chamber wall surface curves;

corresponding to the cylinder profile, the parameter equation of the rotor curve is as follows:

wherein alpha is a variation parameter, the numeric area is [0,2 pi ], beta is a rotor rotation angle;

when the rotor rotates along the rule of the equation, the motion of the rotor is planetary gear motion, no matter the angle to which the rotor rotates, the rotor curve and the cylinder profile are in a tangent state, the tangent points constantly fall on the curves of the three sections of isolation belts, and adjacent combustion chambers are isolated from each other through the tangent points falling on the isolation belts in the middle of the adjacent combustion chambers.

Further, on the seal pin action line, the distance between the intersection point of the cylinder body profile and the seal pin action line and the intersection point of the rotor profile and the seal pin action line is the effective distance between the seal pin and the rotor; if the distance between the rotor and the seal pin is smaller than the effective distance, the seal pin is in contact with the side face of the rotor, and the seal pin is in a sealing state; if the distance between the rotor and the seal pin is larger than the effective distance, the seal pin is not in contact with the side face of the rotor, and the seal pin is in an idle state.

The invention has the beneficial effects that:

1. according to the rotor curve and the cylinder body profile, the adjacent cylinder bodies are isolated by adopting the smooth circular arc which is in stable transition with the combustion cavity profile, the motion mode of the rotor is ensured to be planetary gear motion, the rotor and the cylinder bodies are in a tangent state no matter which angle the rotor rotates, and the tangent point is inevitably on the isolation belt curve, so that the rotor of the engine can rotate more stably in consideration of the disappearance of the boundary sharp point on the cylinder body profile, the operation characteristic of the engine is improved, and the structural wear effect can be well prevented; the structural wear effects due to the high speed rotation of the rotor will also be substantially reduced.

2. The engine sealing mode of arranging the sealing pin rows on the smooth arcs at all the boundaries can effectively improve the sealing performance of the engine and prevent gas leakage between adjacent cylinder bodies; the increase of the number of the seal pins increases the coupling error margin between the cylinder body and the rotor, and the processing cost of the engine can be further reduced.

3. The rotor provided by the invention adopts the shape of the ellipse-like curve, so that the structural processing difficulty can be effectively reduced, and the production cost of an engine is reduced.

Drawings

In order to illustrate embodiments of the present invention or technical solutions in the prior art more clearly, the drawings which are needed in the embodiments will be briefly described below, so that the features and advantages of the present invention can be understood more clearly by referring to the drawings, which are schematic and should not be construed as limiting the present invention in any way, and for a person skilled in the art, other drawings can be obtained on the basis of these drawings without any inventive effort. Wherein:

FIG. 1 is a schematic view of the engine head cover configuration of the present invention;

FIG. 2 is a schematic view of the engine lower end cover and rotor structure of the present invention;

FIG. 3 is a schematic illustration of the engine isolation band and seal pin arrangement of the present invention;

FIG. 4 is a schematic illustration of the engine seal pin configuration of the present invention;

FIG. 5 is a graph of the distance between the seal pin and the rotor as a function of rotational angle for a single rotational cycle of the present invention;

fig. 6(a) -6 (h) are schematic views of the sealing principle of the sealing pin array at different stages of the engine of the invention.

The reference numbers illustrate:

1-upper end cover; 2-lower end cap; 3-a rotor; 4-a combustion chamber; 5-oil injection ignition device; 6-isolation belt; 7-sealing pin rows; 7.1-seal pin; 7.2-seal pin; 7.3-seal pin; 7.4-seal pin; 8-eccentric drive shaft; 9-a screw; 10-a chute; 11-a spring; 12-sliding seal piece.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

As shown in fig. 1-2, a high-sealing elliptical rotor-like engine comprises an upper end cover 1, a lower end cover 2, a rotor 3, three combustion chambers 4, three sections of isolation belts 6, an oil injection ignition device 5, a sealing pin row 7 and an eccentric driving shaft 8, wherein,

the upper end cover 1 and the lower end cover 2 are connected through a screw 9 to form a cylinder body of the engine;

the hollow cavity in the cylinder body is a working cavity for the work of an engine and is used for the rotation of the rotor 3 and the thermodynamic cycle of the three combustion cavities 4, and the working state in the working cavity is determined by the molded line of the cylinder body and the molded line of the rotor 3;

the overall profile of the cylinder body molded line is triangular, three protruding inward concave cavities are uniformly distributed around the cylinder body for one circle to form three combustion cavities 4, the cylinder body molded line is formed by three combustion cavity 4 wall surface curves and three sections of isolation belt 6 curves, and the three combustion cavity 4 wall surface curves and the three sections of isolation belt 6 curves are distributed around the cylinder body for one circle in a staggered manner, so that the cylinder body molded line is rotationally symmetrical at 120 degrees;

the overall outline of the rotor 3 is elliptical, and the central hollow of the rotor 3 is connected with the central hollow of the upper end cover 1 and the central hollow of the lower end cover 2 through an eccentric driving shaft 8; the top parts of the three combustion chambers 4 are respectively provided with an oil injection ignition device 5 for oil injection and ignition;

when the engine works, the rotor 3 is restricted to do planetary gear motion through the eccentric driving shaft 8 and the cylinder body molded line, the rotor 3 rotates, compression-expansion periodic motion is formed in the three combustion chambers 4, the compression-expansion motion is circulated twice when the rotor 3 rotates for one circle, the oil injection ignition device 5 performs oil injection and ignition on the interiors of the three combustion chambers 4 when the compression stage is finished, so that independent thermodynamic cycle is formed in the three combustion chambers 4 in the thermal cycle process, the rotor 3 is driven to rotate together, and useful work is output outwards through the eccentric driving shaft 8;

the sealing pin row 7 formed by at least four sealing pins is equidistantly arranged on the three sections of isolation belts 6, the sealing pins are arranged in pin holes in the three sections of isolation belts 6, sliding grooves 10 are arranged on the inner walls of the pin holes, the sealing pins can slide through the sliding grooves 10, the sliding range is limited through stop blocks at the ends of the sliding grooves 10, the bottoms of the sealing pins are connected with the bottoms of the pin holes through springs 11, the length of the springs 11 directly influences the action size and the action range of the sealing pins, and arc-shaped sliding sealing pieces 12 are arranged at the heads of the sealing pins.

The curves of the three isolation belts 6 are all circular arc curves, and the parameter equation is as follows:

wherein m is the number of the isolation belt, the value range is 1-3, and three sections of isolation belt curves are respectively represented; t is a variation parameter, and the value range is [ -1.0,1.0 ]; k is a cylinder shape coefficient, and the value range is 10.0-12.0; e is the eccentricity of the eccentric column on the eccentric driving shaft, and the value range is 0.005 m-0.007 m; q is a three-section isolation belt shape parameter, represents the ratio of the curvature radius of the isolation belt to the eccentricity of an eccentric column on the eccentric driving shaft, and has a value range of 3.0-6.0;

the wall curves of the three sections of combustion chambers 4 are in smooth transition at the intersection with the curves of the three sections of isolation belts 6, and the parameter equation of the wall curves of the three sections of combustion chambers 4 is as follows:

wherein theta is a variation parameter and the value range isAndthree sections of combustion chamber 4 wall curves are respectively formed;

corresponding to the cylinder profile, the parametric equation of the rotor 3 curve is:

wherein, alpha is a variation parameter, the numeric area is [0,2 pi ], beta is the rotation angle of the rotor 3;

when the rotor 3 rotates along the rule of the equation, the motion of the rotor is planetary gear motion, no matter the angle to which the rotor 3 rotates, the curve of the rotor 3 and the profile of the cylinder body are in a tangent state, the tangent points constantly fall on the curves of the three sections of isolation belts 6 respectively, and the adjacent combustion chambers 4 are isolated from each other through the tangent points falling on the isolation belts 6 in the middle of the adjacent combustion chambers.

In the above equations, when the parameters k, e, q take different values within a feasible range, different engine schemes can be obtained. Compared with the original X engine, the cylinder body profile and rotor profile curve is corrected, so that the dividing sharp point of the original curve dividing the adjacent combustion chamber wall surfaces is expanded into a section of circular arc isolation zone with a certain length, and the rotor curve is improved from the original double-arc epicycloid to an ellipse-like curve, so that the processing difficulty of the engine rotor can be greatly reduced, and the processing cost of the cylinder body profile and the rotor profile can be reduced.

In order to ensure that good sealing performance still exists between adjacent cylinders in the high-speed rotation process of the rotor 3, the engine is provided with sealing pin rows 7 formed by at least four sealing pins which are arranged on three sections of isolation belts 6 at equal intervals, the sealing pin rows 7 are kept in constant contact with the side walls of the rotor 3 in the rotation process of the rotor 3, and areas on two sides of the sealing pin rows 7 are stably sealed and isolated through sliding sealing pieces 12, so that the flow leakage between adjacent combustion chambers is reduced, and each combustion chamber is ensured to have good sealing performance. On the action line of the seal pin, the distance between the intersection point of the cylinder body profile and the action line of the seal pin and the intersection point of the rotor 3 profile and the action line of the seal pin is the effective distance between the seal pin and the rotor 3; if the distance between the rotor 3 and the seal pin is smaller than the effective distance, the seal pin is contacted with the side surface of the rotor 3 and is in a sealing state; if the distance between the rotor 3 and the seal pin is greater than the effective distance, the seal pin is not in contact with the side surface of the rotor 3, and the seal pin is in an idle state.

The invention provides a high-sealing elliptical rotor engine from the viewpoints of preventing structural wear, reducing gas leakage and reducing production cost, provides a new design scheme for a rotor and cylinder molded line, and introduces a sealing pin row to seal transition areas among different combustion cylinders on the basis.

In order to improve the operating characteristics of the engine and prevent the structure of the engine from being worn, the invention provides a novel rotor profile and a novel cylinder profile. Different from the idea that the X engine scheme utilizes the boundary sharp point to isolate the adjacent cylinder bodies, the scheme provided by the invention adopts a smooth circular arc which is in stable transition with the outline of the combustion cavity to isolate the adjacent cylinder bodies. The scheme after the improvement still can guarantee that the rotor motion mode is planetary gear motion, and no matter what angle the rotor rotates to, the rotor all keeps tangent state with the cylinder body, and tangent point must fall on the median curve. Considering the disappearance of the sharp point of the boundary on the cylinder body molded line, the rotation of the engine rotor is more stable, and the structural wear effect generated by the high-speed rotation of the rotor is greatly weakened.

In order to improve the sealing performance of the engine and prevent gas leakage between adjacent cylinder blocks, the invention provides a novel engine sealing mode on the basis of profile change. In order to ensure that a new engine has better sealing performance, the engine provided by the invention arranges the sealing pin array consisting of a plurality of sealing pins on the smooth circular arcs at all the boundaries, and the combined action of the plurality of sealing pins in the rotation process of the rotor is ensured, so that the action length of the pressure difference between adjacent combustion cylinders is prolonged, the pressure gradient in a leakage channel is reduced, and the gas leakage between the cylinder bodies is effectively reduced. In order to meet the above requirements, the sealing pin array arranged on the smooth circular arc should ensure that at least two sliding sealing pins in the sealing pin array are in a sealing state no matter when the rotor rotates to any position. Considering that when the sealing pin array only has two sliding sealing pins, the two sealing pins are sealed in a staggered way, and the effect is similar to that of a single sealing pin; when the sealing pin row only has three sliding sealing pins, the sealing pin in the middle of the sealing pin row is constantly sealed, and the sealing pins on two sides are sealed in a staggered mode, so that the sealing pin row is not different from a single sealing pin. In view of the above, the number of seal pins included in the seal pin row arranged on the smooth arc should be greater than or equal to 4 to satisfy the requirement of the present invention.

In order to reduce the difficulty of structural processing and reduce the production cost of an engine, the invention provides a new rotor curve. Compared with a quasi-triangular curve used by the Wankel engine rotor and a double-arc epicycloid used by the X engine rotor, the quasi-elliptic curve adopted by the invention has the advantages of simpler shape, smaller processing difficulty and lower processing cost, and is more suitable for large-scale industrial production. Due to the increase of the number of the seal pins, the coupling error margin between the cylinder body and the rotor is increased, and therefore the processing cost of the engine can be further reduced.

For the convenience of understanding the above technical aspects of the present invention, the following detailed description will be given of the above technical aspects of the present invention by way of specific examples.