EP0673470B1 - Perfectionnement aux moteurs a combustion interne - Google Patents

Perfectionnement aux moteurs a combustion interne Download PDF

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Publication number
EP0673470B1
EP0673470B1 EP94926266A EP94926266A EP0673470B1 EP 0673470 B1 EP0673470 B1 EP 0673470B1 EP 94926266 A EP94926266 A EP 94926266A EP 94926266 A EP94926266 A EP 94926266A EP 0673470 B1 EP0673470 B1 EP 0673470B1
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EP
European Patent Office
Prior art keywords
valve
working chamber
piston
engine
combustion
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Expired - Lifetime
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EP94926266A
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German (de)
English (en)
French (fr)
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EP0673470A1 (fr
Inventor
Jean Frédéric Melchior
Thierry Andre
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Melchior Technologie SNC
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Melchior Technologie SNC
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/28—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of coaxial valves; characterised by the provision of valves co-operating with both intake and exhaust ports
    • F01L1/285—Coaxial intake and exhaust valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/24—Safety means or accessories, not provided for in preceding sub- groups of this group
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B25/00—Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/14—Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke
    • F02B25/145—Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke with intake and exhaust valves exclusively in the cylinder head
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the present invention relates to a improvement to internal combustion engines, operating according to the two-stroke cycle, with injection of liquid fuel sprayed under high pressure, such as two-stroke diesel engines. More specifically the invention relates to an incorporated gas exchange system exclusively in the cylinder head and intended in particular for organize a stratification between the products of combustion of the previous cycle and fresh air introduced into the working chamber for the next cycle in order to reduce heat loss to the walls and ensure the conditions for a quality combustion process quite remarkable while maintaining excellent efficiency, called scanning efficiency, of the exchange system gas.
  • wet surface Another factor that decreases the yield of a engine, in particular a two-stroke engine, is linked to the area of the so-called “wet surface”, that is to say of the internal surface of the volume where the initiation of fuel injection and the start of combustion, and which generally includes the surfaces of the piston, cylinder head, valves and remaining cylinder part discovery at top dead center.
  • the wet surface poses, in effect, cooling and loss problems of energy.
  • the two valves open towards the inside of the associated cylinder and, during the scanning phase, penetrate, into positions simultaneously open, in the combustion chamber proper formed by a suitable recess in the piston head at top dead center of it.
  • This configuration is perfectly suited to the solution of the scanning problem specific to the four-cycle operation only time.
  • the radially outer valve is annular in shape hollow open.
  • the radially internal valve cooperates with a seat secured to the underside of the valve radially external and the latter cooperates with a seat fixed integral with the cylinder head.
  • Radially internal valve defines a conduit annular with and in the radially external valve.
  • the radially internal valve is preferably used to the exhaust while the radially outer valve serves on admission: however the functional layout reverse is also possible but without providing the same benefits of scanning the dead volume of the cylinder.
  • each valve is actuated separately by independently opened by its own rocker against the opposing force of its own return spring automatic to the closed position and when individual valve opening movement radially external.
  • FR-A-1,127,166 describes a form special hollow intake valve for engines of that type.
  • the air intake duct, upstream of the valve intake, is arranged with fins or a vane of deflection, so as to produce an air movement swirling intake intended to descend along the cylinder wall and then to go up centrally, the air swirling to improve the mixture of fresh air and fuel by providing fuel injectors opening into the periphery of the combustion chamber, at a steep angle to the direction radial.
  • the valves are sized, in their shape and in their lift stroke, so that the passage offered, on admission, to fresh gas is significantly higher than the passage offered, at the exhaust, combustion gases.
  • Another object of the invention is to increase the efficiency of gas exchange by chasing axisymmetrically part of the residual burnt gases of the cylinder by replacing them with a corresponding volume of air costs, while preventing or minimizing everything risk of direct passage of fresh air from the valve of admission to the exhaust valve, or indirect by the mixture of fresh air with the burnt gases leaving the cylinder, with minimal energy expenditure.
  • the energy expenditure is minimized by the search for best use of the purge air supplied to the cylinder, but also by obtaining a large permeability, i.e. by making sections maximum flow offered to gaseous fluids, do not thus requiring a relatively low pressure difference low between purge air pressure and exhaust back pressure to ensure air flow given sweep.
  • Another object of the invention is to ensure the protection of the side walls of the working chamber by the centrifugal circulation of fresh air along these walls.
  • Another objective of the invention is to minimize, in an engine in which a stratification is established elevated gas in the cylinder, the so-called surface area wet, i.e. the internal surface delimited by the piston head, possibly the upper part of the cylinder, and the entire internal surface of the sky from cylinder head in contact with hot gases under pressure this which not only prevents poor combustion at neighborhood of the walls but still considerably limits the heat losses and, therefore, results in significant increase in engine efficiency.
  • Another object of the invention is to reduce the forces applied to the valve control means exhaust while the pressure in the room work is high.
  • Another particularly important objective of the invention is to use the solution to these problems provided by the invention, to produce an engine in which the very phase of combustion is improved, in particular by eliminating the classic disadvantages of compression ignition engines linked to the difficulties of obtaining both complete combustion, substantially free of unburnt matter and smoke and an absence of pollutants such as nitrogen oxides (NO x ).
  • NO x nitrogen oxides
  • Finely pulverized fuel is introduced in the combustion chamber in the form of droplets.
  • each droplet vaporizes and the fuel vapor diffuses in this medium creating an area where spontaneous ignition conditions are affected, fuel ignition occurring there then spontaneously.
  • the time between the start of fuel injection and the start of combustion, at during each cycle is called the "ignition delay”.
  • This first phase of combustion is very serious: fuel vapor, pre-mixed with air hot (under pressure and temperature conditions required for auto-ignition), ignites en masse.
  • the reaction rate is very high and very quickly each partially vaporized droplet consumed the all of the oxygen in the air that is mixed with steam.
  • the mixture not being homogeneous, unmixed air does not have time to maintain the combustion, given its distance from the center (the droplet) of combustion. Very quickly, the reaction therefore stops or at least slows down due to the depletion of available oxygen.
  • This phase of mass combustion (uncontrolled combustion) is called the "combustion in pre-mix" (in English "pre-mix combustion”).
  • Diesel engine manufacturers have therefore striving to reduce the ignition delay (for example by delaying the time fuel is introduced) while seeking to cool the fresh air admitted into the cylinders, so as to increase the density and not exceed cycle temperatures as much as possible above which nitrogen oxides tend to stand produce in excessive quantity, which tends to increase the ignition delay.
  • the solutions they proposed have so far not been entirely satisfactory, particularly point of view of the yield and the emission of particles and exhaust fumes.
  • the invention aims to solve so original the problem of shortening the deadline of ignition, without exceeding the temperatures cycle above which the production of oxides of nitrogen becomes too important, not only by remedying to the drawbacks mentioned above, but still in allowing to burn more "rustic" fuels, having in particular a lower cetane number, and therefore cheaper to produce.
  • the subject of the invention is a combustion engine internal according to claim 1.
  • the said central hub is fixed relative to the cylinder head.
  • the minimum internal diameter of the aforesaid conical bearing oriented towards the outside of the tubular lower part of the valve exhaust cooperating with a seat fitted inside from the lower part of the intake valve is smaller than the outside diameter of the sliding of the above sealing means of the central hub around which slides the inner wall of the lower form tubular exhaust valve to make it slightly autoclave.
  • Various means of elastic return of the valve intake and / or exhaust valve can be planned. These means may in particular include springs mechanical type. These springs can be constituted by a plurality of springs mounted in barrel and exerting their restoring force on a crown integral with the part upper part of the valve.
  • means return springs such as springs, return means elastic of the inlet valve and / or the valve exhaust comprising a piston integral with the valve and sliding in a cylinder defining a cavity of variable volume communicating with means generating fluid pressure.
  • Said fluid pressure generating means can, for example, consist of a sliding piston in a cylinder forming a second volume cavity variable communicating with the aforesaid first cavity, the piston being actuated by a motor means such as a shaft cam rotating synchronously with the motor shaft.
  • the driving piston which delimits the engine work by sliding in the cylinder wall, and which is sealed by a seal offering no passage for the working fluid towards the part lower piston, can be arranged so that its upper part wife, with sufficient play to avoid the formation of radial air movements likely to destroy the axisymmetric rotation movement of the fluid engine, the part of the cylinder head located outside the maximum diameter of the inlet valve and the valve admission itself when the volume of the chamber of work is minimal, i.e.
  • the sealing means of the inner wall of the tubular upper part of the exhaust valve sliding around the above central hub may include a seal continuous offering no passage for compressed working fluid in the working chamber, the lower form tubular exhaust valve and part lower of the central hub thus delimiting a cavity annular in which will be trapped a quantity of air not participating in the combustion of the injected fuel in the working room and which will relax during the stroke to increase the volume of the working chamber.
  • the distributor means constituted in particular by the above-mentioned valves of such so that a significant part of the cycle's combustion gases previous is retained in the working chamber during the process of removing flue gases and partially replace them with fresh air, by opening exhaust and intake valves during the phase sweep in the two-stroke engine.
  • the communication between the intake cavity and the working chamber, when the inlet valve is in open position, on the one hand, and the shape of the walls of the working chamber, on the other hand, are arranged so that the flow of fresh air enters the combustion, while the volume of the working chamber becomes minimal due to the relative movement of the piston, so as to cause an intense rotational movement of the fluid inside the combustion chamber, preventing as much as possible, thanks to the centrifugation of the fresh air obtained by this rotational movement and at the density difference between fresh air and combustion, the fresh air to mix inside the combustion chamber with combustion gases retained in the latter, and forming in said combustion chamber a central area where the concentration of combustion gases and the temperatures are maximum and a peripheral zone where the concentration of fresh air is maximum and the temperature is minimal.
  • the injector can inject the fuel directly into the said central area, at least at the beginning of each period injection.
  • the mass of the combustion gases retained in the working chamber, from one cycle to the next, is at least 10%, preferably 15%, of the mass of the working fluid contained in this last chamber at the when communications between it and one and the other of the above intake and exhaust cavities have just been interrupted during each cycle, then that the engine is running at least approximately at its nominal speed.
  • the inlet air temperature and the proportion of gases retained in the working chamber, one cycle on the other taking into account the other parameters of operation of the engine, so that if mixed retained gases and fresh air before injecting the fuel, the temperature of the mixture thus obtained at time of injection may be less than when self-ignition of the fuel occurs so stable and without excessive unburnt production.
  • This improvement has the advantage of allowing both intensively cool the fresh supply air (for limit the thermal load on the walls and reduce maximum cycle temperatures at values below those that cause excessive oxide formation harmful nitrogen) and to have an effective volumetric ratio reduced (to limit the mechanical load of the parts), everything maintaining perfect self-ignition conditions, with reduced ignition delay.
  • the reference 1 designates a cylinder of a diesel engine two-stroke, of longitudinal axis 2, containing a piston 3 and whose upper end is surmounted and closed by a cylinder head generally designated by the number of reference 4, comprising a central fuel injector pressurized liquid 5 coaxial with the cylinder and surrounded coaxially by two concentric valves, respectively internal exhaust 6 and external intake 7, delimiting between them a generally annular exhaust duct 8 burnt gas which communicates with an exhaust pipe 9 connected to the exhaust system (not shown) of the engine.
  • the inlet valve 7 is in the form of revolution, hollow and open at each end, and whose the lower end 13 has a sole shape and externally has a conical annular bearing sealing 14 facing outwards and upwards, that is to say towards the breech, and cooperating with a fixed seat 15 integral with the cylinder head 4, and internally a conical annular surface 16, oriented inward and upward, and serving as a seat axially movable at an annular sealing surface conjugate 17 arranged at the lower terminal part or free end of the exhaust valve 6.
  • the valve 7 is guided in its axial sliding by the external lateral wall of its tubular tail 18, in a valve guide 19 integral with the cylinder head 4.
  • Radially external intake valve 7 delimits with the cylinder head 4, in its lower part located in the immediate vicinity of its scope cooperating with the conical seat secured to the cylinder head, clearance admission ring 10 communicating with a pipe 11 fresh air intake connected to the intake system (not shown) of the engine, for example a overeating.
  • the upper end of the tail 18 of the inlet valve 7 has a flange 23 making annular piston office sliding tightly in a coaxial cylinder 24 arranged in the cylinder head 4, delimiting with this one a room 25 on the upper side of this piston, and a chamber 26 under the underside of this piston.
  • the radially internal or exhaust valve 6 has substantially the form of axis revolution confused with that of the intake valve and preferably confused with the axis of the above-mentioned engine cylinder 1, of a sleeve tubular located inside the inlet valve 7 and sliding axially by its internal lateral surface on a valve guide 20 forming part of a central hub 21 integral with the cylinder head 4.
  • This central hub 21 contains, by elsewhere, the fuel injector 5, including the nozzle spray 22 opens into combustion chamber 40 in order to be able to inject fuel jets substantially radial and preferably inclined and distributed in a star around the nozzle.
  • the upper end of the tubular sleeve constituting the radially internal or exhaust valve 6 has a flange 12 acting as a piston annular sliding tightly in a cylinder coaxial 31 fitted in the cylinder head 4, delimiting with this one a room 32 under the underside of this piston, and a chamber 33 on its upper face.
  • the seal between the external side wall of the tubular valve stem 18 of the inlet valve 7 and the valve guide 19 secured to the cylinder head 4 on the one hand, between the inner side wall of the tubular sleeve of the exhaust valve and the valve guide 20 integral with the central hub 21 on the other hand, as well as the seal between the aforesaid flanges 12 and 23 acting as a piston and the cylindrical walls 24 and 31 arranged in the cylinder head 4, is provided by a set of one or more ring seals, rings or seals, preferably radially expandable.
  • the piston 23 of the intake valve 7 and the cylinder 24 constitutes a fluid cylinder under pressure to actuate said valve 7 in the direction of opening lift (downwards, i.e. towards piston 3).
  • the upper chamber 25 of this jack is intended to receive a hydraulic fluid under pressure, preferably incompressible, such as oil, which will also ensure the lubrication of the tracks sliding of the seals, to cause positively the descent of the piston 23, therefore of the valve 7, in the open position, while the lower chamber 26 underlying contains elastic return means 34 of the valve in the closed position.
  • These elastic return means may be made up of mechanical springs 29 comprising, preferably a plurality of springs mounted in parallel to the way of a barrel and angularly regularly distributed around the edge of the collar so as to ensure a uniform cushion over its entire perimeter. They may also or concurrently be constituted by a pressurized fluid, preferably compressible, supplying the above lower chamber 26.
  • the generation of hydraulic pressure in the upper chamber 24 of the aforesaid cylinder can advantageously be carried out by communicating the aforesaid room 24, through passages 30, with a pump cylinder (not shown), filled with incompressible hydraulic fluid and closed by a pump piston actuated by a camshaft rotating in synchronism with the main motor shaft.
  • this pump piston can be actuated by any other known means such as actuator with control hydraulic, electromagnetic, or other.
  • the entire collar 12 acting as piston of the exhaust valve 6 and of cylinder 31, constitutes a pressurized fluid cylinder to actuate said valve 6 in the lifting direction opening (upwards, i.e. in the opposite direction piston 3).
  • the lower chamber 32 of this cylinder is intended to receive a hydraulic fluid under pressure, preferably incompressible, such as oil, to positively cause the piston 12 to rise, so the valve 6 lifted, in the open position, while the underlying lower chamber 33 contains means for elastic return 34 of the valve in the closed position.
  • These elastic return means may be, in the same way way, mechanical, hydraulic or preferably, and concurrently, tires.
  • deflectors 37 intended to give the intake air, when the intake valve is lifted, a moment kinetics likely to generate a rotational movement, with an axis substantially coincident with axis 2 of the engine cylinder, ensuring a centrifugal helical path to the air streams fresh entering the working chamber.
  • deflector means may be constituted by the shape of said intake pipe. There will be more simply consist of blades inclined relative to the axis of said cylinder, or more simply by angularly drilled holes regularly distributed over the periphery of said annular clearance of admission and axes preferably perpendicular and not intersecting with respect to the axis of said cylinder. This last provision is particularly advantageous for facilitating transmission towards the breech of the vertical forces due to the pressure of gas in the working chamber.
  • This tubular sleeve arrangement of the exhaust valve 6 is particularly advantageous in the sense that, unlike a valve conventional mushroom shaped gas pressure prevailing in the working chamber, at the time of opening of said valve, does not oppose, or very little, this openness: the effort developed by the control unit the lift of the exhaust valve will be reduced in consequence, which will facilitate the realization.
  • the exhaust valve control device for achieve a very important engine brake: indeed if we has a timing device, variable during the engine operation, opening control valve, we can, by significantly anticipating the moment the exhaust valve opens start of the downward stroke of the piston (corresponding to the increase in the volume of the working chamber of the engine) drop the pressure in this chamber of work and will reduce the positive work of the engine accordingly and, consequently, increase the engine brake.
  • This advance opening of the exhaust valve, while the pressure in the working chamber is very important, will be painless due to the tubular shape of this valve.
  • the peripheral intake valve 7 is strongly cooled by the intake air during the phase sweep.
  • the coolant will be advantageously introduced by means of supply conduits and back 39 which will primarily irrigate the part lower of the central hub 21 in the vicinity of the nose of injector 5, then on the return circuit, the space annular 38.
  • the axi-symmetrical arrangement of this allows follow the air streams introduces trajectories helical away from them as long as possible from the central area close to the exhaust and reduce to maximum the mixture between the fresh air introduced and the combustion confined to the center of the working chamber.
  • the piston 3 has, in its upper face, a recess 40 of axis revolution confused with that of the piston and which constitutes for essentially the combustion chamber, while the volume of the working chamber is minimal, the piston being at near top dead center.
  • the nozzle 22 for injecting liquid fuel under injector 5 pressure is located substantially in the axis of the combustion chamber in such a way that the fuel is injected, preferably in the form of inclined and regularly distributed radial jets, in the central part of the combustion chamber.
  • the amount of flue gas at very high temperature and low in oxygen, concentrated in the area central combustion chamber can be obtained and easily adjusted.
  • the temperature of the central zone can be of the order of 1480 ° C. just before injection while the temperature of the fresh air rotating device is in the order of 430 ° C.
  • the upper side piston 3 located outside the combustion chamber 40 is preferably flat and comes to marry, with a play that we will determine in order to minimize the importance of radial air movements when the piston is in the vicinity from its top dead center, the underside of the sole 13 of the intake valve 7. In doing so, it comes, when the piston is near the top dead center, trap radially outside the conical seat 15 a small annular volume 46.
  • this small annular volume 46 constitutes a "dead end" in which is established, at each compression cycle of the piston, a supply of fresh air and turning away from the fuel combustion when the piston is in the vicinity from top dead center.
  • this air reserve will relax, protecting so thermally, by developing a layer cold limit, the upper crown of the piston 3 and the face bottom of the sole 13 of the intake valve 7.
  • FIG 2 we see another embodiment of the invention which is distinguishes from that shown in Figure 1 by the fact that the elastic return means of the intake valves and exhaust here are purely pneumatic, the chambers 26 for the intake valve and 33 for the exhaust valve communicating through passages 39a for the intake valve and 39th for the exhaust valve with a cavity (not shown), supplied with air under pressure.
  • this figure shows the means generating vertical forces making it possible to lift the intake and exhaust valves for the disconnect cyclically from their respective seats.
  • These means essentially consist of a camshaft 50 rotating in synchronism with the main motor shaft and comprising an intake cam 51a and a cam exhaust 51st.
  • These cams operate the pump pistons 52a and 52e sliding freely axially in the pump cylinders 53a and 53e, thus delimiting cavities of variable volume 54a and 54e which communicate by passages 55a and 55e with the upper cavities 25 of the jack of the inlet valve 7 and lower 32 of the cylinder of the exhaust valve 6.
  • All of these circuits hydraulic (54a, 55a, 25) and (54e, 55e, 32) are filled an incompressible fluid such as oil.
  • each pump piston 52 thanks to the action of the cam 51, will cause the lifting of the corresponding valve with a stroke equal to the stroke of the cam multiplied by the ratio of cross sections pump piston and valve cylinder.
  • the cam nose has exceeded the angular position allowing the pump piston to be released, the means of elastic return of the corresponding valve will recall both the valve on its seat and the pump piston at the contact with the cam.
  • FIG. 3 we see another embodiment of the invention which differs from that shown in Figure 1 first of all by a number of details. So the conduits of 39 coolers are arranged differently.
  • the annular admission clearance 10 is arranged in the external lower part of the intake valve 7 and not not in the cylinder head 4.
  • the piston 23a of the external valve 7 is arranged in an intermediate position and the spring 29 requests, upwards, an annular ring 41 carried by the valve 7 in the vicinity of its upper end.
  • the exhaust 6 and intake 7 valves have, in their cylindrical part, a double wall leaving inside a free space, which can be optionally traversed by a cooling fluid.
  • the air reserves annulars formed at the periphery of the cylinder to the outside of the conical seat of the intake valve (Annular reserve 46) on the one hand, and that constituted around the central hub 21 on the other hand, will feed in relaxing, when the piston begins its downward stroke, the boundary layers of fresh air set in motion during injection, thanks to the very high momentum transferred to the surrounding environment by the fuel jets injected under very high pressure.
  • These boundary layers thus drawn in will protect the walls of the chamber from combustion and "feed" fresh air around the periphery of fuel jets to supply the necessary oxygen to the combustion of fuel inside two contra-rotating vortices generated by injection under very high fuel pressure in the chamber, thus facilitating mixing with the fuel and this makes the speed and quality of combustion.
  • the engine piston is shown 3 in its lower position, near the bottom dead center, at when it starts to go up to reduce the volume internal free in cylinder 1.
  • the means of control (not shown) introduce liquid hydraulic under pressure in chamber 32, which instantly causes the exhaust valve to lift 6, the bearing 17a of which deviates from the seat 16 of the valve 7 remained closed, connecting inside the cylinder, through line 8 with the line exhaust 9, while the return spring 34 of the exhaust valve is compressed.
  • the lower curved part 42 of the exhaust valve came substantially tangent to the convex end lower of the hub 21 so that the space 43 is not noticeably more in communication with the combustion, so that the exhaust gas flow without disturbance. This flow continues gradually as the piston 3 goes up and removes part of the combustion gases.
  • valve 7 drops to the position shown in the figure.
  • the exhaust valve 6 remaining in its raised position, the section of the passage between the internal face, which carries the seat 16 of valve 7 and the bearing 42 opposite valve 6 is greatly enlarged, which facilitates the pursuit from the flue gas outlet at a time when the pressure in the cylinder has already dropped.
  • lowering the valve 7 causes the intake passage to open, so that the annular clearance 10 is put in communication with the interior of the cylinder by a passage 49 orienting gradually the air towards the lower side wall of the cylinder and down thanks to the concave curvature of the external surface of the intake valve 7 at the clearance 10, helped in this by the taper or the curvature, going outward and downward, from the part of cylinder head at the external seat 14 of the valve of admission.
  • This stratification remains appreciably present as the volume decreases during the raising of the piston 3, even after having closed the intake and exhaust valves. This stratification still persists in the position shown in the figure 6, near top dead center, in which the volume is now limited to that of combustion chamber 44, which includes the volume of the recess in the surface of the piston, the compressed fresh air rotating at the periphery of the combustion chamber while the poorer hot gases oxygen remain confined to the central volume of the combustion chamber, i.e. in the vicinity of the nozzle central 22 of the injector.
  • the injector starts, towards the end of compression, spraying the liquid fuel, as shown in Figure 5, so that at start of injection, the liquid fuel is at the hot gas contact in the central part of the volume where begins combustion, which takes place in the best conditions. Combustion then continues from the center to the periphery towards the air fresh, which achieves almost uniform combustion perfect, free of pollution and oxide formation nitrogen.
  • this combustion takes place under perfectly axisymmetric conditions in a combustion chamber volume whose surface is minimal since reduced to the visible face of the hub 21, to the lower part of the internal surface of the valve intake, and on the surface opposite the piston 3.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)
  • Glass Compositions (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Valve Device For Special Equipments (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
EP94926266A 1993-09-13 1994-09-02 Perfectionnement aux moteurs a combustion interne Expired - Lifetime EP0673470B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9310853 1993-09-13
FR9310853A FR2710106B1 (fr) 1993-09-13 1993-09-13 Perfectionnement aux moteurs a combustion interne
PCT/FR1994/001033 WO1995008052A1 (fr) 1993-09-13 1994-09-02 Perfectionnement aux moteurs a combustion interne

Publications (2)

Publication Number Publication Date
EP0673470A1 EP0673470A1 (fr) 1995-09-27
EP0673470B1 true EP0673470B1 (fr) 1999-04-07

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EP94926266A Expired - Lifetime EP0673470B1 (fr) 1993-09-13 1994-09-02 Perfectionnement aux moteurs a combustion interne

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US (1) US5555859A (fa)
EP (1) EP0673470B1 (fa)
JP (1) JP3644964B2 (fa)
KR (1) KR100347404B1 (fa)
CN (1) CN1059730C (fa)
AT (1) ATE178694T1 (fa)
AU (1) AU7617594A (fa)
BR (1) BR9405590A (fa)
CA (1) CA2142468A1 (fa)
DE (2) DE4496847T1 (fa)
FI (1) FI952333A0 (fa)
FR (1) FR2710106B1 (fa)
GB (1) GB2285484B (fa)
NL (1) NL9420008A (fa)
RU (1) RU95112530A (fa)
TW (1) TW268991B (fa)
WO (1) WO1995008052A1 (fa)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2741668B1 (fr) * 1995-11-29 1998-03-20 Tacquet Maurice Andre Perfectionnements aux moteurs alternatifs a combustion interne, ceux-ci comportant des culasses a soupapes concentriques
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WO1995008052A1 (fr) 1995-03-23
GB2285484A (en) 1995-07-12
DE69417719D1 (de) 1999-05-12
JP3644964B2 (ja) 2005-05-11
EP0673470A1 (fr) 1995-09-27
KR950703698A (ko) 1995-09-20
TW268991B (fa) 1996-01-21
CA2142468A1 (en) 1995-03-23
FI952333A7 (fi) 1995-05-12
ATE178694T1 (de) 1999-04-15
BR9405590A (pt) 1999-09-08
FR2710106B1 (fr) 1995-12-08
FI952333A0 (fi) 1995-05-12
RU95112530A (ru) 1997-02-10
GB2285484A8 (en) 1995-07-31
DE69417719T2 (de) 1999-12-16
GB9504459D0 (en) 1995-05-10
KR100347404B1 (ko) 2002-10-31
NL9420008A (nl) 1995-08-01
FR2710106A1 (fr) 1995-03-24
CN1059730C (zh) 2000-12-20
CN1113662A (zh) 1995-12-20
GB2285484B (en) 1997-06-04
US5555859A (en) 1996-09-17
DE4496847T1 (de) 1995-10-19
AU7617594A (en) 1995-04-03
JPH08503285A (ja) 1996-04-09

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