WO1998039556A1

WO1998039556A1 - Sakharnov piston engine

Info

Publication number: WO1998039556A1
Application number: PCT/UA1997/000008
Authority: WO
Inventors: Vasily Sakharnov; Leonid Shvedov; Boris Galyan; Alexandr Goldman; Sergei Yakovets; Nikolai Koval
Original assignee: Vasily Sakharnov; Leonid Shvedov; Boris Galyan; Alexandr Goldman; Sergei Yakovets; Nikolai Koval
Priority date: 1997-03-07
Filing date: 1997-07-02
Publication date: 1998-09-11
Also published as: AU3639897A; CA2289223A1; RU2125162C1

Abstract

This engine can be used in different spheres of technic. The engine comprises a casing, a central main shaft and cylinders with the axes parallel to it. Two inclined disks are attached to the ends of the main shaft, on the circumferences of which the rocking cams are installed concentric on the bearings, these cams being connected with a possibility of rocking through journals of the rocking rings, which are connected by their journals arranged crosswise with a possibility of rocking to the engine casing. The rocking cams are connected by rods, having at their ends the ball and socket joints, to their group of the pistons, which in pairs with a possibility of the opposing motion are located in the cylinders. It is achieved simplicity of design, increasing of efficiency and wear steadfastness, decreasing of dimensions and weight.

Description

SAKHARNOV PISTON ENGINE

Technical Field

The present invention relates to manufacture of internal combustion engines and their application in various industries, such as motor industry, tractor and tank industries, ship building, aircraft and power engineering. Improvement to an internal combustion engine consists in ensuring the high- quality operation process and, therefore, energy saving, as well as development of such a design of the engine which would feature high reliability, long service life, low production and operation costs at minimum weight and dimensions. Background Art Many various designs of the internal combustion engines are known in the prior art. They include Otto-cycle petrol engines, Sabate-cycle diesel engines, two- and four- stroke engines with in-line, V-shaped, opposite and radial arrangements of cylinders, with "/ater or air cooling.

The majority of the currently used engines are based on the principle of conversion of translational motion of a piston into the rotary one using a main shaft made in the form of a crankshaft.

Special place among engines of different designs is taken by two-stroke engines with two opposed pistons in one cylinder and with the straight-through scavenging of the cylinders. Such engines are characterized by high performance: they have high efficiency, low fuel consumption, good balance between the first- and second-order inertial forces, high mean effective pressure, high capacity, perfect scavenging and exhaust and easy supercharging.

The main drawback of this type of the engines is a too complicated design with regard to conversion of the opposing-translational motion of two pistons in one cylinder into the rotary motion of an output element. In this case it is necessary to use either two crankshafts synchronized via a power gear train or two sets of connecting rods of different sizes which transmit the motion to one crankshaft.

Such engines, however, have been in the prior art for a long time. Known in the prior art also is the "Junkers" engine manufactured by the German company of the same name and described in book by Eng. VNNlasov "High-speed transport diesel engines", ONTI NKTP SSSR, 1936, Moscow, Leningrad, Chief Editorial Board for Motor and Tractor Industry Literature, p. 213...223.

Such an engine comprises in one cylinder two opposed pistons connected through the connecting rods to one crankshaft, the lower piston being connected to the crankshaft by a short central connecting rod and the upper piston - to the opposite crank of the crankshaft by two long side connecting rods via a balance beam.

The design of such an engine is too complicated, its multi-crank shaft being too expensive and dimensions and weight being too large.

Another example of the prior art engines is an engine manufactured by Company "Burmeister und Wein". This engine is based on the same principle as that of the "Junkers" model and is described in the above book by Eng. VNNlasov "High-speed transport diesel engines", p. 226, 227. The upper and lower pistons in this engine are also connected to one crankshaft through the connecting rods of different sizes, the upper piston having a smaller diameter and. in fact, serving as a slide valve for opening the scavenging ports. Similar engines were manufactured also by other companies and they are described in the literature. Known also is an aircraft engine "Junkers-JuMO" described in detail in the book by A.Dodge "High-speed diesel engines", OΝTI ΝKTP SSSR, 1938, Chief Editorial Board for Machine-Building and Motor ?.r.d Tractor Industry Literature, p. 269...272. In this engine each cylinder houses two pistons which are capable of making opposing-translational motion. But the translational motion of each of the pistons is converted into the rotary motion through a separate connecting rod and crankshaft. Therefore, the engine has two crankshafts connected to each other via a synchronizing power gear train. The engine of such a design is very difficult to manufacture. It comprises two expensive crankshafts, a complicated power synchronizing transmission and a large height and mass.

Therefore, in all the prior art engines the conversion of the translational motion of a piston into the rotary motion is provided using a crank mechanism. The closest to the present invention is a design of the engine with two opposed pistons in each cylinder and transmission of the opposing-translational motion of the pistons converted into the rotary one to the main shaft by two oblique cranks via rocking cams, as described in book by S.Ν.Kozhevnikov. Ya.I.Esinenko and Ya.Ν. Raskin "Mechanisms", Moscow, "Mashinostroyeniye", 1976, p. 128 and 130, Figs. 22-27. The engine consists of a crankshaft having two opposed inclined cranks with the rocking cams installed on them. The rocking cams are connected via ball and socket joints to the cranks, the opposite ends of which are also connected via ball joints to the two opposed pistons located in each of the cylinders, the axes of which are parallel to the axis of the shaft. The opposing-translational motion of the pistons is converted into the rotary motion of the crankshaft through the rocking cams. Injection and ignition of a fuel mixture occur at the upper dead centre, where the pistons in the cylinder and, hence, the corresponding portions of the rocking cams are drawn to each other as close as possible. Fuel gases at a high pressure affect the pistons trying to separate them. In turn, the pistons transmit the force via the connecting rods to the oblique cams also trying to separate them, while the latter make the main shaft rotate, affecting the oblique crank. The rocking cams are kept from rotation with two diametrically arranged pins which can move in the direction coaxial to the engine axis in two curvilinear slots made in the fixed casing of the engine. Thus, the cams can rock only slightly. During operation, the pins take up the reactive torque which is equal to the torque of the engine and, under this force, they move inside the curvilinear slots to a larger distance than a stroke of each of the pistons. This results in the high friction losses in the slots during movement and a decrease in the total efficiency of the engine. Additionally, the known engine has heavy weight, high cost, low accuracy of manufacture and α.«embly, low operational reliability and is hard to manufacture. In their book, Kozhevnokov et al. omit the data on implementation of such a design of the engine in metal. Disclosure of the Invention

The present invention was aimed at an improvement of the prior art internal combustion engines provided by changing a shape of the main shaft, adding new elements and new connections between the existing structural elements. The above improvement made it possible to modify the kinematics of conversion of the translational motion of the pistons into the rotary motion of the main shaft, to decrease the rocking angle of the connecting rods, to compensate for thermal expansions of the main shaft, to balance the masses and arrange them concentrically in the claimed design, to remove the first- and second-order vibrations and, thus, to decrease the friction losses, increase the total efficiency of the engine, raise the accuracy of manufacture and assembly and improve the operational reliability of the engine. The above improvement to the prior art design of the engine with two opposed pistons in each cylinder, axes of the cylinders parallel to the axis of the main shaft and the rocking cams, the pistons in the cylinders being connected via a hinge joint to the connecting rods, the opposite ends of which are connected via a hinge joint to the rocking cams located in a fixed casing of the engine, is that the main shaft is made straight with two opposed inclined disks rigidly mounted on it, the cylindrical surface of each inclined disk having a cam attached to it through ball bearings or hydraulic bearings, the cams having a possibility of spatial rocking and affecting the sloping down sides of the disks and each cam being connected to a ring by two journals located one opposite the other on the inside of the ring, the rings being connected to the engine casing by two other journals located one opposite the other on the outside of the rings, and installed so that they have a possibility of rocking around the axes of the outside journals, the axes of the journals located on the inside and outside of the rings being perpendicular to each other and lying on one plane with a centre of rotation of the disks and a centre of spatial rocking of the cams, while the journals located on the outside of the rings entering the spring-loaded bushings in the engine casing and having a possibility of moving parallel to the axis of the main shaft.

Therefore, claimed is a design of the engine which comprises, in comparison with the prior art, no crank mechanism, including two crankshafts, this making it much simpler, cheaper and more reliable. As the pressure of gases taken up by the pistons via the rocking cams and the inclined disks is transmitted to the main shaft, the engine body is completely relieved from working loads, this enabling it to be made light-weight and caπ ing the loads only due to the engine weight. In the claimed design, the connecting rods are rocking to the angle of 2-3 degrees during movement of the pistons, the friction losses under similar loads acting on the pistons being smaller than in engines with the crank mechanism, where this angle is 15-20 degrees. In engines with a crankshaft a crankpin bearing rotates to 360 degrees under a full load. In the claimed engine the crankpin bearing turns only to 45 degrees, this also aiding in reduction of the friction losses. The use of the rocking rings secured via a hinge joint by journals in the fixed engine with a possibility of their rocking, and of the rocking cams arranged crosswise and mounted on the fixed engine casing also with a possibility of rocking by other journals eliminate the probability of skewing of the connecting rods and, therefore, the probability of damage of the mechanism. In this case the friction losses are minimized, as the reactive torque affects the journals which have a small diameter, as compared to the slots in the prior art design, and turn under this effect to a small angle which is twice as large as the angle of inclination of the cams (the actual value of the latter in practice being 15...25 degrees).

To compensate for thermal expansions of the main shaft and to facilitate achieving the required accuracy of manufacture and assembly, the rocking ring has a possibility of moving along the axis of the main shaft owing to spring loading of the journals through which it is connected to the casing, this decreasing the required accuracy of manufacture, making it easier to assemble the engine and, thus, improving its operational reliability.

Balance of masses and their concentric arrangement make it possible to eliminate the first- and second-order vibrations in the claimed engine design. Therefore, it features a more smooth and reliable operation, and the probability of fatigue fracture of metal is reduced.

Brief discription of the drowings Figure 1 shows a transverse section of the claimed engine; Figure 2 - a transverse section A- A of the engine; Figure 3 - section B-B along the inclined rocking ring, rocking cam and inclined disk.

The engine is designed as follows. Cylindrical casing 1 has main shaft 2 is installed with a possibility of rocking in its central bore (Figs. 1 and 2) preferably on ball bearings. The shaft is prevented from axial displacement by front bearing 3 secured in casing 1 in the axial direction. Two opposed inclined disks 4 which have a possibility of rocking with main shaft 2 are rigidly mounted on the ends of the shaft. Spatially rocking cams 5 are installed preferably on ball or hydraulic bearings at the outside surface of each of inclined ύisks 4, which have a possibility of rotating in them. Spa.Uly rocking cams 5 are kept from rotation together with main shaft 2 and inclined disks 4 by the mechanism consisting of rings 6, which are connected to rocking cams 6 through two diametrically arranged journals 7 (Fig. 3), the rocking cams 5 being capable of rocking around the axis of the journals relative to rings 6 In turn, rings 6 are connected through two other journals 8 arranged crosswise relative to the former, with a possibility of rocking about their axes in fixed casing 1, slide racks 9 being put on the journals. The slide racks have a possibility of moving in the slots of casing 1 along a longitudinal axis of the engine and are loaded by springs 10 in a direction of the longitudinal axis of the engine to compensate for thermal expansions of main shaft 2 and improve accuracy of manufacture and assembly

Therefore, rings 6 and rocking cams 5 are kept from rotation together with main shaft 2 and inclined disks 4 and have a possibility of rocking only in the diametrically opposed directions, each about the axis of their journals.

Rocking cams 5 are connected through ball and socket joints 1 1 to connecting rods 12, the opposite ends of which are connected also through ball εnd socket joints 13 to pistons 14 installed with a possibility of opposing translational motion Two of such pistons are located in each cylinder 15, the cylinders being arranged radially in ports of casing 1 and their axes being parallel to the axis of the main shaft. The drawings show an engine comprising four cylinders, but actually the engine may comprise two or more cylinders. Cylinders 15 have exhaust ports "a" and scavenging ports "b" which are opened and lapped over by pistons 14. The scavenging ports "b" face the scrolls of casing 1 and are connected to each other via collector 16 having an air intake pipe. The exhaust ports "a" also face the scrolls of casing 1 and are connected with the exhaust pipes via the collector.

Injector 17 for injection of fuel during operation of the engine in the diesel mode or a spark-plug for the petrol engine is installed on a perpendicular plane coming through the vertical axis of the engine between the piston bottoms. Flywheel 18 from which the torque generated by the engine is relieved is rigidly mounted on the front end of the main shaft.

Working of the engine The principle of operation of the engine is as follows. During their movement to the centre of cylinder 15, pistons 14 lap over first the exhaust ports "a" and then the scavenging ports "b". A portion of air (in operation in the diesel mode) inside the cavity of cylinder 15 between the piston bottoms is compressed and heated by compression. Fuel is injected to the cavity through injector 17 at the point, called the upper dead centre, where : e pistons are drawn together to the maximum possible distance (maximum possible opposed inclination of rocking cams 6) and, therefore, at the maximum temperature. (Actually, injection of fuel occurs somewhat earlier: it is the so-called injection advance). Ignition of fuel takes place, pressure in the cavity between the pistons increases and pistons 14 transmit the force through connecting rods 12 to the corresponding rocking cams 5 trying to push them apart. Because the cams are kept from rotation and are attached by a hinge joint to rings 6 which, in turn, are connected also by a hinge joint to casing 1 of the engine, they start rocking around journals 7 and affect, through bearings, the sloping down side of inclined disks 4, making them rotate (as if they slide down from the inclined plane), and, as inclined disks 4 are rigidly connected to main shaft 2, it also rotates. At the end of its stroke one piston opens the exhaust port "a" and the combustion products are discharged to the atmosphere. A bit later the second piston opens the scavenging port "b", the incoming air forces out the remains of exhaust gases from the cylinder cavity and fills it with a new portion of air.

At the same time, pistons in the opposite cylinder, under the effect of the rocking inclined disks, the rocking cams and rods, start approaching each other to lap over the exhaust and, then, scavenging ports and compress their portion of the air A process similar to that described above takes place. Thus, the sequential operation of the cylinders provides the continuous rotation of the main shaft.

Therefore, the straight opposing-translational motion of the pistons is converted into the rotary motion of the main shaft.

Advantages of the envention The claimed design can comprise either two cylinders or a group of cylinders with the axes arranged radially parallel to the axis of the main shaft. The number of the strokes per revolution of the main shaft will be equal to that of the cylinders comprised in the engine.

The similar engine can be used also for operation in the petrol mode. The only difference is that in this case a working mixture of petrol and air should be fed to the cylinders instead of air and that a spark-plug should be installed instead of the injector.

The claimed engine has a number of advantages over the existing ones. It has a simple design and can be manufactured using conventional machine tools. It comprises no complicated and expensive crankshaft. The cylinder block has a simple cylindrical shape and bears no working loads, as all the loads due to the pistons are taken up only by the main shaft. It is compact and, hence, has much smaller dimensions and weight. It is characterized by low wear and high mechanical efficiency, i.e., the angle of pressure exerted by the connecting rods on the pistons ^•" by an order of magnitude smaller than that in the engines which comprise crankshafts, this decreasing wear of the cylinders and the pistons and the friction losses during movement of the pistons. At the same time, the connecting rods in the ball-and-socket joints are turned during operation around the rocking cams to the angle of about 40-45 degrees, i.e., the force of friction caused by the pistons acting on the ball-and-socket joints of the rods is effective only on a very small path, whereas the neck of crankshafts in the existing engines in the lower heads of the connecting rods turns to 360 degrees under the same loads, i.e., in the claimed engine the friction losses are smaller. The use of the straight main shaft makes it possible to install it on the rolling bearings, this additionally providing a decrease in the friction losses and an increase in the efficiency, and eliminate the first- and second-order vibrations. Pairs of pistons moving in the opposite directions and in parallel to the main shaft fully counterbalance each other.

Therefore, the engine operates smoothly and with a high efficiency. A prototype of such an engine is now manufactured by the authors at one of the factories in Kyi v.

Claims

CLAIMThe Sakharnov engine with two opposed pistons in each cylinder, the cylinder axes parallel to the axis of the main shaft and with the rocking cams, the cylinder pistons being connected via hinge joints to connecting rods the opposite end of which are connected via hinge joints to the rocking cams located in a fixed casing of the engine, characterized by the fact that the main shaft is made straight with two opposed inclined disks rigidly mounted on it, the outside surfaces of each inclined disk having a cam connected to it through ball bearings or hydraulic bearings with a possibility of spatial rocking and affecting the sloping down sides of the disks, each cam being connected to a ring through two journals located one opposite the other on the inside surface of the ring, the rings being connected to the engine casing through two other journals located one opposite the other on the outside surface of the ring with a possibility of rocking around axes of the outside journals, the journal axes on the outside and inside surfaces of the rings being perpendicular to each other and lying in one plane with the centre of rotation of the disks and the centre of spatial rocking of the cams, the journals located on the outside surface of the rings entering the spring-loaded sleeves of the engine casing and hav;r.« a possibility of moving parallel to the axis of the main shpft. AMENDED CLAIMS[received by the International Bureau on 10 March 1998 (10.03.98); original claim 1 replaced by amended claim 1 (1 page)]

1. Λxial-piston engine incorporating a stationary block

with located in parallel around a circumference cylinders

with two pistons mounted in mirror reflection in each

cylinder, power shaft mounted in the block centre on

bearings, and carrying on the block end faces two

oppositely-inclined discs with spatially-rocking washers

mounted on the discs on bearings, the washers being

connected to the pistons via rockers with ball bearings and

held to prevent their rotation relative to the block,

characterized by that the engine is fitted with two rocking

rings each of which has on the outer side two

opposite-lying pins hinged to the block through

spring-loaded slides entering the longitudinal slots of the

block with the capability of displacement in parallel to

the power shaft axis and self-positioning; likewise from

the inner side the rocking rings have two cylindrical pins

located normal to the outer pins and hinged to the

space-rocking washers, here the axes of all the four pins

are in the plane of the rocking ring, in parallel pairs,

the point of intersection of the pins axes coinciding with

the centre of spatial rocking of the washers and point of

intersection of the axes of inclined discs with the power

shaft axis.