EP3980632A1

EP3980632A1 - Synchronous two-stroke "servo piston" service unit with floating ring for endothermic engines

Info

Publication number: EP3980632A1
Application number: EP20744148.6A
Authority: EP
Inventors: Salvatore FIORETTI
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-06-04
Filing date: 2020-05-26
Publication date: 2022-04-13
Also published as: CA3138257A1; GB202115258D0; WO2020245854A1

Abstract

The SERVO-PISTON propulsor aims to improve the energy output efficiency generated within the engine, it operates individually as it does not require further devices, it distinguishes itself by its ability to develop a new kinematic process thanks to a new stroke called "scission", which basically divides the device into two sections: the central section, with a central disc connected to the rod, that drags the external one shaped like a "floating ring". It does not require additive oil in the fuel, it provides low consumption even if compared to the four-stroke engines as it is not subordinated to any type of valves, which absorb power, complicate the functioning, raise temperatures and oblige the employment of specific antiknock petrols. With such specifications one gets the benefit to employ a sole thermodynamic cycle for the complete turn of the camshaft, therefore this efficiency makes it a two-stroke system.

Description

Synchronous two-stroke "servo piston" service unit with floating ring for endothermic engines

TECHNOLOGY FIELD WHICH THE INVENTION REFERS TO

The mobility and the intended use of the unit presented is aimed at all those vehicles equipped with internal combustion engines in a condition of what can be moved in relation to the space-time movement. It is employed for transportation generally for leisure, for work and for sports competitions, in relation to people or things.

THE STATE OF THE ART AND THE PREEXISTING TECHNOLOGY

Two-stroke engine - The age of the two-stroke engine, as is well known, is slowly drawing to an end, abandoned by the majority of the motor industry despite the capacity that this system is still be able to express and despite it appearing to be still valid from the point of view of versatility, compactness and constructive simplicity, which dictated a low cost production and sale.

However a strong use still remains in environments in which

environmental norms are less restrictive, for instance for motocross competitions in the mountains, for boats in the nautical field and for snowmobiles on the snow but, as for road use, nowadays it has been abandoned even for motorcycles . Work tools deserve a separate

discussion; chainsaws, blowers, current generators and scale model making for leisure. TECHNICAL PROBLEM - The reasons for the decline of the two-stroke engine are precisely the severe anti-pollution norms in force in the cities and in the inhabited centers, the high consumption and the burden of adding oil to the fuel.

FOUR-STROKE ENGINE - The demand for increasingly efficient and clean engines and the economic and the sports competition have led the evolution of this engine type to high levels thanks to laborious technologies, such as the computerized electronics, the direct injection, the electromechanical valves and the turbo compressor which, although the latter brings benefits at a functional level, cannot be maintained to be also successful in containing polluting emissions. As a matter of fact turbo engines, by exploiting the exhaust gas pressure, decrease the gas' ability to be filtered. And it is logic to think that this matter has come to a climax and that further developments in that direction will gradually decline given the advance of battery-powered electric propulsors .

TECHNICAL PROBLEM - A symptomatic factor that slows down the evolution of the four-stroke engine is certainly determined by mushroom valves which, though still indispensable, at the same time set limits due to their inefficient function; they absorb part of the energy produced, waste an amount of petrol for their own cooling at high speeds and there is a further waste during the so-called crossover phase. EXPOSITION OF THE INVENTION It is advanced the solution of the above-mentioned problems with the presentation of the subject matter of the patent which consists of a service unit called "servo-piston" , in short S/P (Fig. 1) . The invention is proposed as innovator of an aged two-stroke machinery or as evolution of what the four-stroke engine represents today. On the motoring scene the product is

presented as a novelty since it introduces an atypical kinematic mechanism conceived as auxiliary function of technical aid, which operates with its own geometric logic in synergy with the principal piston. The peculiarity of this new technology is aimed at the purpose of the process optimization related to the production of mechanical energy in a more efficient way, allowing at the same time to eliminate completely the mushroom-shaped distribution system by replacing it with equivalent but simple lamellar valves, which are encased in the upstream pipe and placed upon the top dead center (hereafter called "TDC") of the S/P for the inlet and downstream for the outlet. In the cylinder chamber the valves are interposed in the space between the bottom dead center (hereafter called "BDC") of the S/P and of the principal piston (hereafter called P/P) . However that allows the employment of these materials, which are definitely more fragile than the mushroom valves, but they are also less stressed because the devices are not exposed in the combustion chamber and not involved in the detonation. THREE-STROKE SYSTEM - The system architecture has been designed on the basis of the S/P' s peculiarity, which is to carry out two simultaneous activities (plus an extra one) out of the four functional

thermodynamic strokes of the Otto cycle named "service strokes", which comprise the fresh mixture suction stroke simultaneously combined with the burnt gas exhaust stroke and an extra one called "scission", hereafter explained. The remaining strokes, those of compression and expansion called "active", are dependent on the power unit represented by the principal piston.

PROPULSION FUNCTION - The work carried out by the S/P in the cylinder chamber is comparable to that of a plunger turned upside down which moves in a rectilinear reciprocating motion with its direction parallel to the major axis of the cylinder (in this case, by way of example, in vertical direction) from the TDC to the BDC and vice versa, opposite and synchronized to the primary piston, and operates with a rapid motion. In fact it acts as a propulsor which is able to generate at the same time pression and depression in one motion from top to bottom, it is subordinated to the turn of an altered overhead camshaft and subjected to a derivative desmodromic mechanism.

DISTINGUISHING CHARACTERISTICS

PASSIVE FUNCTION - As for the moving central section of the S/P, (Fig. 1 point 4) the particular installation of this unusual device allows the pouring of the fluid mass (fresh charge) into the same cylinder, it opens when moving upwards during the service stroke, thus carrying out a singular function understood as "scission" . The automatism of this section is developed in a dynamic way from a mass that moves by inertia and that becomes compact when moving downwards and decomposes into two sections when moving upwards: the central part, which is well fixed to the rod, shaped like a circle and the external part shaped like a floating ring. (Fig. 1 point 7)

COMBUSTION CHAMBER - In other words it is the space that takes shape when the S/P is in the top dead center TDC (end of stroke) , at that moment it assumes the shape and the function of head, thus forming the upper section of the cylinder chamber. Right at the time the end of stroke is reached in the TDC, in the head the S/P temporarily forms the top of the combustion chamber, namely the space in which the air- fuel mixture is confined at the end of the P/P's compression stroke. TWO-STROKE - It is determined that with the above-mentioned

specifications one has the capacity to employ a sole thermodynamic cycle for one complete turn of the camshaft, therefore this

functionality is characterized by the two-stroke principle. THE BORE AND THE STROKE LENGTH - The geometry of the architecture is designed by calculating the margins of the kinematic process, which is expressed by the value of the "Superguadro" ratio (short-stroke) since the bore value is bigger than the stroke length. This choice is the ideal solution that brings: functional benefits, a decrease in the excursion of the S/P and consequently a reduction in the volume of the organs connected to it.

ANTI-SEIZURE - The S/P is not particularly exposed to the complication of the seizure as it operates attached to the rod, which moves it in a perfectly linear way, exempt from lateral forces, favoured moreover by its ability to rotate on its own axis. In addition to that, in order to prevent seizure and ensure the lubrification, one row of ball bearings is encased in a groove that encircles the S/P (Fig.l point 10) and they are immersed into a special grease for high temperatures (like molybdenum disulphide) which makes the motion smoother and reduces the friction with the cylinder pipe. The whole is closed, partitioned and hermetically protected between two compression rings (Fig.l point 8,9) of the synthesized type (carbide, tungsten and steel alloy) .

SIZE - The circumference is the same as the bore of the primary piston. Thicknesses and weights are situational, defined by the design values, the condition of use and the materials employed. QUICK AND ACCURATE - These adjectives sum up the reactive nature of the S/P unit and the steadiness of the perfectly linear stroke. These benefits are achieved thanks to the fact that the S/P is not attached to a connecting rod but to a linear rod and thanks to the consequent absence of lateral forces (given by the effect of flaring due to the upward and downward motion generally related to pistons) .

THE HOUSING - The section is defined as the seat of the S/P in the point of upper end of stroke TDC, it draws an analogy with the valve seat of the four-stroke engine from which it takes the technology and the materials employed for the making of this section.

THE SPARK PLUG - It is laterally located for the positive ignition of the combustion and appropriately housed in the upper part of the cylinder, in the combustion pseudo-chamber, therefore it is no longer in the head but it is laterally located, which is an obliged solution to allow the passage of the S/P.

THE MATERIALS AND THE SHAPE - Aluminum alloy forged, from an aesthetic point of view it is similar to a big mushroom valve where, at the center of the disc, is evident a circular intersection. The latter in fact is the passive valve with a tail which is represented by a sturdy linear rod (Fig. 1 point 1), whose extremity is predisposed for the contact of the equalizers (Fig.l 2,3) . The whole surface is enclosed by the two compression rings which contain the row of inox ball bearings . THE COOLING - In addition to the centralized system of the engine that also cools the cylinder, the S/P enjoys a further benefit due to a thermic exchange and achieved by the fresh charge both during the suction stroke and the scission stroke.

INTEGRATED SYSTEM - All the technologies described in this report take shape in the upper section of the four-stroke engine. The remaining components, which are normally employed for what they have been designed, remain unchanged and they are the pistons, the connecting rods, the camshaft, the change gear, the clutch, the transmissions, the electronic injection, the radiators, part of the distribution, all the electric system of lubrification and the cooling, etc...

The following study in depth is pointed out by simulating the

employment of the S/P in a vertical single-cylinder spark ignited petrol fuelled two-stroke engine.

In order to get optimum efficiency from this new technology for the construction of a modern engine, two old technologies have been selected along with a third traditional mechanical organ whose functions are connected with each other and carry out combined actions. It is specified that the S/P is an individual organ which is an end in itself; the connected technologies, hereafter explained, are not binding to its functioning and it can be connected to any device that puts it into motion, be it mechanical, electric or pneumatic in order to get the above-mentioned benefits. THE FIRST TECHNOLOGY - The choice of the S/P' s command system falls on the derivative of a little-known system of distribution named

"desmodromic". It is distinguished by an essential characteristic, the employment of a faster and more accurate recall mechanical method of the valves; the size of such a system is not sufficient so it is implemented with a structural oversizing, proportionally at an approximate scale of 1:5, notwithstanding the faithfulness to the criterion which it has been invented for. The whole architecture has been clearly designed for an accurate synchrony of the S/P

subordinated to the stroke rate of the P/P, which follows the stroke with a uniform and regular rhythm.

THE RATE - Appropriately calibrated, the S/P' s command system balances the travel with only two movements (push and pull) with a different rhythm and it is run by a single two-cam shaft setting. Being

conceived in this way, it is able to develop a greater load with the necessary energy amplifying the range of action of the equalizer and thus increasing the excursion.

PERTINENT - It is involved, in the same context, a third element as well, an aid-worker of the overhead activity, namely the common

"camshaft" which interfaces among the parts creating a connection: constrained in the new architecture, it gets altered as well and in fact, by getting elaborated, its size gets enlarged, specifically the one of the cams (eccentrics) which are definitely much larger, in order to allow a longer excursion on the two independent equalizers (arms), which in their turn operate alternately on the axis of the

S/P. THE SECOND TECHNOLOGY - In order to optimize the S/P' s potential at its best, a very versatile passive (it does not absorb energy) one-way distribution device has been adopted and re-used, better known as "lamellar pack", originally used in many two-stroke engines (and air compressors), mainly during the suction stroke (fresh mixture), but now it is also employed as outlet valve, located on the burnt gas outlet pipe at the base of the cylinder. It is made up of a series of lamellae (in carbon, steel, fibre, etc.) which regulate the fluid dynamics of gases that enter the two-stroke engine cylinder.

THE FUNCTIONING - As for the inflow stroke, the principle is similar to the employment in the traditional two-stroke engine but in

different modes and times, the function occurs during the stroke in which the S/P moves downwards, therefore in the cylinder chamber a depression is generated and the lamellar valve, which is located at the top in the cylinder pipe, opens up in the inward direction of the cylinder itself, thus favouring the inflow of the fresh charge, and closes up again once the depression ceases due to the filling of the cylinder chamber. In the next stroke, the exhaust one following the detonation and the gas expansion, a resonance, which produces a pressure increase in the cylinder, is generated; the lamellar valve, which is located on the outlet in the lower part of the cylinder pipe, by receiving pressure, opens up in the outward direction allowing the burnt gas evacuation and after that it immediately closes up, once the pressure ceases and the S/P moves back up. THE THREE FUNCTIONS CARRIED OUT BY THE SERVO-PISTON

THE EXHAUST - Starting from the TDC, the device intervenes with a little delay after the detonation by calculating the gas expansion time coefficient, the gases give the push to the P/P in the downward stroke, followed by the S/P, which on the contrary is moved by the pulse received from above ( camshaft-desmo combo) and by the dynamic suction backpressure (drag phenomenon determined in a gas mass) generated by the wave. During the stroke from top to bottom the S/P, driven by pressure, from the "B" side quickly pushes the exhaust burnt gases outwards to the lamellar valve (lamellar pack), which has meanwhile opened up following the pressure exerted on it, and to the outlet .

THE SUCTION - In the course of the cleaning (exhaust) stroke, which takes place on the "B" side of the S/P, at the same time on the "A" side the other phase of work occurs, namely the suction (the inflow of the fresh charge, the fuel) ; the S/P slowly pushes the burnt gases from the "B" side and simultaneously from the "A" side sucks up the reload. The latter moves down into the empty space, favoured by the depression generated, which in its turn has enabled the lamellar inlet valve (located at the top) to open inwards, thus favouring the inflow of the fresh charge (air/petrol mixture or other fuel) directly into the cylinder chamber and allowing the complete filling; at that point the lamellar inlet valve closes up following the lack of depression.

Once the servo-piston reaches the BDC, it has completed the two first phases of the first stroke. THE SCISSION - It is the division of the S/P into two parts, basically it is a new supplementary stroke. This function is possible thanks to the passive valve that allows the advent of the new function, which does not belong to the well-known thermodynamic cycle, and it is precisely described as "functional service stroke". The dynamic process is carried out in the following way: once the BDC is reached (namely the position where the P/P and the S/P are opposite one another) , after having discharged the gases to the outlet and

preloaded the cylinder chamber with the fuel from the "A" side, the S/P moves back up a little in advance of the P/P (drawn back up by the camshaft/desmo combo) and generates a turbulence which pours the mass of particles (fresh charge) into the chamber after passage through the opening of the passive valve. The maneuver occurs thanks to the braking given by the friction of the S/P' s external section

compression rings coming into contact with the cylinder chamber' s sheath (dragged by leash) .

Once the stroke is completed, at first the central section of the S/P (valve) houses in its end of stroke in the TDC and immediately afterwards the external section aligns again to the central one, thus reassembling the S/P, thanks to a spiral spring inserted between the two parts (Fig. 1 point 12) and to the compression thrust given by the following piston. FUNCTIONAL EVOLUTION OF THE PRIMARY PISTON

The role played by the power unit (primary piston) in the cylinder chamber in association with the fellow S/P is scaled down to only two active strokes and the piston rate is completely the same if compared to the four-stroke engine, but the background changes. The difference in the process is not made by the piston in itself with its

reciprocating motion but by its fellow S/P, which with its aid reduces the strokes from four to two increasing the active work of the piston during the charge compression stroke and the expanding pressure stroke and making itself responsible for the two service strokes, as already described. The shape assumed by the piston, which best fits for this employment, is the Cupa type (like the diesel), characterized by a short skirt with concave top, and it allows to best collect the combustible mixture at the center of the piston, which best absorbs the expanding gases thus limiting the recoil, namely the pressure heading in the opposite direction.

KINEMATIC SEQUENCE OF THE THERMODYNAMIC PROCESS

1^st Stroke Regular/ 1^st Action/l^st Phase/Expansion/Downwards

Once the optimum point of compression in the cylinder chamber is reached (Fig. 2), in the TDC the spark goes off and immediately the detonation of the fuel mixture occurs, followed by the burnt gas volumetric expansion stroke, and the piston moves downwards (Fig. 3 and 4) reaching the BDC (Fig. 5), thus already completing half turn of the camshaft. 1^st Stroke Del. /2^nd Action/2^nd Two-phase/Exhaust/Downwards/A Side

Afterwards, in the same first stroke, the S/P follows the action of the P/P (Fig. 3 and 4) downwards with a little delay (Del.) carrying out the exhaust stroke from top to bottom and pushing the burnt gases towards the lamellar outlet valve (Fig. 5) .

1^st Stroke Del. /2^nd Action/2^nd Two-phase/Suction/Downwards/B Side

At the same time the S/P, in the same above-written action always from top to bottom, from the "A" side carries out the fresh charge (fuel) preload retro suction stroke (being the fresh charge introduced by a high depression) filling all the space of the stroke from top to bottom in the same cylinder chamber (Fig. 3,4,5) .

2^nd Stroke Advance/3^rd Action/3^rd Phase/Scission/Upwards

This completely new stroke, named scission, consists of the advance restart of the S/P from the BDC right before the piston which, by decomposing into two sections and opening up its central valve, manages to move back up cleaving the fresh charge, poured from the "A" side to the "B" side, to move back into its seat at the end of stroke in the TDC and then to reassemble, thus forming at that point the top of the head.

2^nd Stroke Regular/4^th Action/4^th Phase/Compression/Upwards

Finally the primary piston follows the servo-piston upwards pushing the fluid mass, which is in stasis condition, by compressing it to the top close to the S/P which, at that moment, serves as head (moved by the camshaft that has meanwhile completed the turn) . THE SYNTHESIS - The sequence of events previously described starts with the piston moving down during the expansion stroke, the S/P follows it and from the "B" side pushes the discharged exhaust gases to the outlet and, at the same time, completes the filling of the cylinder chamber by sucking up the fresh charge from the "A" side, then it moves back up during the scission stroke followed by the piston, which in its turn by moving upwards pushes and compresses the fresh charge to the top close to the S/P. At the time when the S/P and the P/P reach the TDC, once the optimum point of compression is achieved, the spark goes off and ignites the fuel, which by imploding generates the expansion wave. Then it starts again for the following turn of the thermodynamic cycle according to what has already been said about the functioning of this new system.

ADVANTAGES AND PECULIARITIES OF AN ENGINE WITH THE SERVO-PISTON

COLD HEAD - It is favoured by the absence of the outlet overhead mushroom valve, which considerably overheats to the passage of the exhaust burnt gases. Moreover additional benefits are derived during the gas exhaust stroke, which takes place from the lower point of the cylinder. As a consequence the exhaust gases remain less time in the cylinder chamber and, once they have expanded after the detonation, they directly flow out in only one stroke as they are no longer driven back upwards to the outlet valve with consequent overheating of the head due to heat radiation. THERMAL EFFICIENCY - Thanks to the cold head one profits from a better thermal efficiency, if compared to the current combustion engines in which only about a third of the energy developed during the combustion of the air-fuel mixture is transformed into mechanical energy. The rest ends up being wasted, lost in the outlet or transferred to the cooling system.

COMPRESSION RATIO - This matter is once again linked to the cold head, in fact thanks to the latter' s property the phenomenon of the auto ignition does not occur, therefore the compression ratio value reaches higher levels .

CONSUMPTIONS/EMISSIONS/FUELS - The purpose is to waste less fuel, passing from the reduction in the moving elements within the engine and from the thermic efficiency ratio in relation to the motion energy produced, with consequent reduction in exhaust gases and in their respective harmful emissions in the environment. It is not bound to the employment of specific fuels in relation to the octane number. DISCHARGES/SIZE/WEIGHT - There is a considerable reduction in the overall volume and in its respective weights under the same output power. The exhaust manifolds are arranged below at the base of the cylinder so that they are shorter and less articulated, moreover they provide further advantages related to the discharge of possible harmful impure residues thanks to the gravity force.

Claims

1. The synchronous two-stroke "servo piston" service unit with transfer floating ring for endothermic engines

It includes :

(1) Full (not hollow) connection stem to the central plate body.

(2) Stem end for the downward beat point.

(3) Fulcrum on the stem for the upward connection contact.

(4) Central disc section.

(5) Perimeter edge of the central disc.

(6) Convex stairstep section for the matching of the central disc with the external ring.

(7) Flat external floating ring.

(8) Upper compression ring of the circular flat open carbide alloy metallic L-shaped type.

(9) Lower compression ring turned upside down (of the same type as above ) .

(10) One row of stainless steel ball bearings interposed between the compression rings.

(11) Concave stairstep section for the matching of the flat external ring with the central disc section.

(12) Stainless steel return spring for the closure of the external ring .

2 . As defined in the claim in point 1, the servo-piston is

characterized by the fact that it is an individual plunger-shaped device in aluminum alloy and for its functioning it does not require any other additional device. It operates in a rectilinear

reciprocating motion oriented along the major axis of the cylinder, it is opposite to the principal piston in the chamber of the same cylinder and turned upside down at the top in the head in the top dead center TDC. At the beginning it works from top to bottom, (Fig.2) and carries out two simultaneous strokes (at the same time) : the gas pressure-driven forced exhaust stroke from the lower part (B side) and the one related to a particular preloading function in the part of the same cylinder whose inlet is on the upper part (A side) . At a later stage, it develops a new third stroke described as "scission", which is characterized by an upward movement from the bottom dead center to the top dead center. Basically the servo-piston divides into two parts, after the opening of its external section named "floating ring", which cleaves the fresh preload in the part of the cylinder previously sucked up and pours it downwards from the upper part of the cylinder itself (Fig.6), thus turning the preload into fresh charge, and then reassembles in one element in the TDC at the end of stroke thanks to a spiral spring inserted between the two parts (Fig. 9), thus forming the top of the engine head. The pressure tightness with the cylinder wall, both during the suction stroke and the exhaust one, is ensured by two L-shaped compression rings at the center of which is interposed one row of rotating ball bearings for the anti-seizure system. The tightness for the matching of the fixed section with the servo-piston' s moving section is ensured by the concave and convex shape of the surfaces in contact.