CH236284A

CH236284A - Internal combustion engine with compression ignition and variable compression.

Info

Publication number: CH236284A
Authority: CH
Inventors: Anonyme International Societe
Original assignee: Int Motors Company Societe Ano
Priority date: 1940-11-29
Filing date: 1941-10-07
Publication date: 1945-01-31

Description

Moteur ä combustion interne ä allumage par compression et ä compression variable. Dans la construction de moteurs ä com- bustion ä allumage par compression, deux tendances contraires se font actuellement jour. Internal combustion engine with compression ignition and variable compression. In the construction of compression-ignition combustion engines, two opposing trends are presently emerging.

La premiere de ces tendances, qui resulte de 1'obligation d'obtenir 1e demarrage des mo- teurs ä froid, par n'importe quelle tempera- ture atmospherique extérieure, porte ä ad- mettre des taug de compression élevés. The first of these tendencies, which results from the obligation to obtain the starting of the engines cold, by any outside atmospheric temperature, leads to admitting high compression taugs.

La seconde de ces tendances, qui provient du desir de diminuer la fatigue des Organes mécaniques du moteur et 1e degagement de chaleur dans les articulations, tend au con- traire ä adopter pour 1e régime normal du moteur, ä pleine Charge, 1e taug de com- pression 1e plus bas possible, compatible avec une consommation économique. The second of these tendencies, which comes from the desire to reduce the fatigue of the mechanical parts of the engine and the release of heat in the joints, tends on the contrary to adopt for the normal engine speed, at full load, the com- taug - 1st pressure as low as possible, compatible with economical consumption.

Un grand nombre de moteurs modernes sont par ailleurs suralimentés, c'est-ä-dire que les cylindres moteurs sont remplis, au debut de la compression, d'air venant de la soufflante ou du compresseur, ä une pression plus forte quo celle de 1'atmosphére. 0r, lors de la mise en marche du moteur, qui se fait toujours ä un nombre de tours de loin infe- rieur ä celui du regime normal, 1'action die suralimentation n'intervient en général pas, et 1e taug de compression au départ doit dans ce cas être ohoisi de façon ä assurer 1e départ ä froid sann tenir campte de la suralimenta- tion. Cela eonduit ä des pressions de colm- pression absolument excessives en regime normal. Dans ces moteurs egalement, an a donc, le cas échéant, avantage ä chereher de faire dininuer 1e taug de compression apres 1e démarrage. A large number of modern engines are also supercharged, that is to say that the engine cylinders are filled, at the start of compression, with air coming from the fan or the compressor, at a higher pressure than that of the atmosphere. However, when the engine is started, which is always done at a number of revolutions far lower than that of the normal regime, the supercharging action does not generally intervene, and the compression taug at the start must in this case be chosen in such a way as to ensure a cold start without taking into account overcharging. This leads to absolutely excessive compression pressures in normal operation. In these engines too, it is therefore advantageous, if necessary, to seek to cause the compression taug to decrease after starting.

0n a dejä cherché ä realiser des dispo- sitifs permettant de faire diminuer 1e taug de compression d'un moteur aprés 1e demarrage et an a propose la solution bien connue sui- vant laquelle 1e volume total de la chambre de combustion est divise en deux comparti- ments par un canal trés etroit, que Von bauche au depart ä 1'aid@e d'un pointeau. L'in- convenient de ce dispositif réside dann 1e fait que fair enferme dann 1e deuxiéme conpar- timent ne se trouve en communication avec 1a, chambre dass laquelle se fait l'injection du combustible que par 1e canal étroit mentionne plus haut et ne peut aider ä la combustion avec pleine efficaeite. 0r, c'est justement en regime et pleine charge que la totalite de Pair disponible doit intervenir. Attempts have already been made to provide devices for reducing the compression gauge of an engine after starting and the well-known solution has been proposed whereby the total volume of the combustion chamber is divided into two compartments. - ments by a very narrow channel, which you rough out at the start with the aid of a needle. The inconvenience of this device lies in the fact that the chamber enclosed in the second compartment is only in communication with the chamber in which the injection of fuel takes place through the narrow channel mentioned above and cannot help combustion with full efficiency. 0r, it is precisely in regime and full load that the totality of available Pair must intervene.

L'invention a pour objet un moteur ä. combustion interne ä allumage par com- presssion et ä compression variable ne présen- tant pas cet inconvenient. Ce moteur est caractérise par un organe pouvant coulirser dans 1e eylindre et formaut 1e fond de celui-ei, et par un arbre dost Faxe de rota- tion est fixe par rapport au cylindre et auquel sont transmises leg pressions de compression et de combustion agissant sur l'organe cou- lissant, cet arhre presentant un maneton excen- trique reue audit organe coulissant de façon qu'en faisant tourner cet arbre an deplace Forgane coulissant longitudinalement dann 1e cylindre, un mécanisme permettant de bloquer cet arbre dass deux positions pour chaeune desquelles 1e volume de 1a chambre de combutstion a une valeur differente. The subject of the invention is an ä motor. internal combustion with compression ignition and with variable compression not having this drawback. This engine is characterized by a member which can slide in the cylinder and forms the bottom of the latter, and by a shaft whose rotation axis is fixed with respect to the cylinder and to which the compression and combustion pressures acting on the cylinder are transmitted. the sliding member, this shaft having an eccentric crank pin received by said sliding member so that by rotating this shaft, it moves the sliding member longitudinally in the cylinder, a mechanism making it possible to block this shaft in two positions for each of which the volume of the combustion chamber has a different value.

Le moteur suivant 1'invention pourra.it aussi etre un moteur suralimenté. The engine according to the invention could also be a supercharged engine.

Le desein annexe represente, à titre d'exemple, deux formen d'exeeution de l'objet de 1'invention. The appended design represents, by way of example, two embodiments of the object of the invention.

La fig. 1 est une vue en coupe axiale de la, premiere forme d'exécution; La fig. 2 est une vue en coupe axiale suivant un plan perpendiculaire ä celui de la fig. 1; La fig. 3 est une vue en coupe axiale de la deuxiéme forme d'execution; La fig. 4 est une vue en coupe axiale sui- vant un plan perpendiculaire ä celui de 1a fig. 3. fig. 1 is an axial sectional view of the first embodiment; fig. 2 is an axial sectional view along a plane perpendicular to that of FIG. 1; fig. 3 is an axial sectional view of the second embodiment; fig. 4 is an axial sectional view along a plane perpendicular to that of FIG. 3.

Dass 1es deux formes d'exéeution repre- sentees, 1e fond du cylindre 5, dans 1equel coulisee 1e piston 6, est constitué par un organe coulissant 7. Dass un plan axial du, cylindre est moste un arbre 8, t maneton excentrique 9 et pivoté dass des coussinets 10 fixes à 1'extremite dudit cylindre 5. In the two embodiments shown, the bottom of the cylinder 5, in which the piston slide 6, is constituted by a sliding member 7. In an axial plane of the cylinder is most of a shaft 8, the eccentric pin 9 and pivoted in bearings 10 fixed at the end of said cylinder 5.

Dass 1a premiére forme d'execution, la liaison entre 1e maneton 9 et l'organe cou- lissant 7 est constituée par un coulisseau 11, articulé sur ce maneton 9 et pouvant cou - lisser dans ute glissiere 12 formee dans un prolongement exterieur de 1'organe 7. In the first form of execution, the connection between the first crankpin 9 and the sliding member 7 is constituted by a slider 11, articulated on this crankpin 9 and able to slide in a slide 12 formed in an external extension of 1 organ 7.

Sur une extension 13 de Faxe 8 est fixe un levier de commande 14 pourvu Tun verrou ä ressort 15 qui coopere avec des encoches 16, 16' menagées dans un secteur 17 pour bloquer ledit levier de eommande dass deux positions extremes situees ä 180 environ l'une de l'autre. Fixed on an extension 13 of faxe 8 is a control lever 14 provided with a spring-loaded latch 15 which cooperates with notches 16, 16' made in a sector 17 to lock said control lever in two extreme positions located approximately 180 one from the other.

Les deplacements angulaires du levier 14 produisent 1a, rotation correspondante de Farbre 8 dont 1e maneton. dass son mouve- ment excentrique, entraine 1e coulisseau 11 qui coulisse dans la plissiere 12, ce qui pro- duit un deplacement axial de l'organe eou- lissant 7 dass 1e cylindre. Cet orga.ne 7 est ainsi amene de son point 1e plus haut à son point 1e plus bas, ou inversement. suivant 1e Seens du deplacement angulaire du levier 14. The angular displacements of the lever 14 produce the corresponding rotation of the shaft 8, including the crankpin. Its eccentric movement drives the slider 11 which slides in the pleat 12, which produces an axial displacement of the sliding member 7 in the first cylinder. This organ 7 is thus brought from its first highest point to its first lowest point, or vice versa. following the 1st Seens of the angular displacement of the lever 14.

Dass les positions extremes de 1 organe 7, qui correspondent chacune ä un volume diffe rent de ka chambre de combustion, l'axe géo- metrique (a) de Farbre B. ainsi que laxe (h) du maneton excentrique 9, se trouvent pra- tiquement dass un plan axial de l'organe cou- lissant, de sorte que les efforts transmis à ce dernier par 1a compression et la combustion ne donnent pas lieu ä un moment de torsion qui tendrait ä faire tourner automatiquement l'arbre B. Le verrou 1a, qui bloque 1e méea- nisme dans les deux positions mentionnées empêche en outre tout deréglage qui pourrait se produire par suite des trépidations du mateur pendant 1a marche. In the extreme positions of the member 7, which each correspond to a different volume of the combustion chamber, the geometric axis (a) of the shaft B, as well as the axis (h) of the eccentric pin 9, are close to each other. - only in an axial plane of the sliding member, so that the forces transmitted to the latter by the compression and the combustion do not give rise to a torque which would tend to cause the shaft B to rotate automatically. lock 1a, which locks the mechanism in the two mentioned positions, moreover prevents any misadjustment which could occur as a result of the operator's tremors during operation.

Pour la misse en marche du moteur, an améne l e levier 14 dans sa position de blocage correspondant ä la position la plus hasse de lürga.ne coulissant dass 1e cylindre, pour obtenir la compression la plus forte. Attssitöt apres les premieres combustions et sann per mettre au moteur (1e prendre sott allure de régime, an degage 1e verrou 15 et an fait tourner 1e levier 14 pour 1e bloquer dann sa Position correspondant ä la position la plus elevee de 1'organe 7, qui est celle choisie pour le régime normal du moteur. To start the engine, one brings the lever 14 into its blocking position corresponding to the lowest position of the slider in the first cylinder, to obtain the strongest compression. Attssitöt after the first combustions and without allowing the engine to take a slow speed, an releases the first lock 15 and an rotates the first lever 14 to block it in its position corresponding to the highest position of the member 7, which is the one chosen for the normal engine speed.

La course effectuee par 1'organe 7 Jans ses deplacements dune Position ä 1'autre, est montrée en fig. 1 et correspond ä la distance c comprise entre les deux positions angu- laires extremes de Faxe du maneton 9. The travel performed by the member 7 in its displacements from one position to another is shown in FIG. 1 and corresponds to the distance c comprised between the two extreme angular positions of Faxe of the crankpin 9.

La liason telle qu'etablie dans les fg. 1 et 2 pour gelier le maneton 9 ä l'organe cou- lissant 7 pourrait aussi Ure constituée par une Biellette articulée, dune pari, audit ma- neton et, d'autre Part, audit organe. The link as established in fg. 1 and 2 to freeze the crankpin 9 to the sliding member 7 could also be constituted by an articulated connecting rod, on the other hand, to said crankpin and, on the other hand, to said member.

Dans la forme d'exécution du moteur montrée en fig. 3 et 4, 1'organe coulissant formant 1e fond du cylindre travaille comme piston distributeur, et est commande par des cames entraînées par 1'arbre moteur. In the embodiment of the motor shown in FIG. 3 and 4, the sliding member forming the bottom of the cylinder works as a distributor piston, and is controlled by cams driven by the motor shaft.

Dons ce moteur, les lumieres 18 d'echap- pement sollt commandées par 1'organe cou- lissant 7 agissant comme piston distributeur. Celui-ei est munie d'un tourillon 19 auquel esst articulee une kellette 20, articulee, d'autre pari, au moyen d'un tourillon 21 portant un galet 22 guidé par une came 23, ä l'une des extrémités de chacun de deux leviers coukés 24 pivotant sur 1e maneton excentrique 9 de Farbre 8 auquel sonnt trans- mises les Pressions de compression et de com- bustion du moteur. La Biellette 20 et les leviers paralleles 24 forment une genouillére. In this engine, the exhaust ports 18 are controlled by the sliding member 7 acting as a distributor piston. This one is provided with a trunnion 19 to which is articulated a kellette 20, articulated, on the other hand, by means of a trunnion 21 carrying a roller 22 guided by a cam 23, at one of the ends of each of two crank levers 24 pivoting on the eccentric crankpin 9 of the shaft 8 to which the compression and combustion pressures of the engine are transmitted. The connecting rod 20 and the parallel levers 24 form a toggle joint.

Lautre extremité de chaque levier 24 Porte un galet 25 et ces galets 25 cooperent avec deux camas 26 entraînées par 1e moteur et portees par 1e même arbre que la came 23. The other end of each lever 24 carries a roller 25 and these rollers 25 cooperate with two cams 26 driven by the first motor and carried by the same shaft as the cam 23.

Les cames 23 et 26 sollt desmodromiques, c'est-ä-dire qu'elles présentent des Profils conjugués, de façon ä communiquer aux leviers 24 1a meme loi de mouvement autour du maneton 9, de façon ä definir strictement à chaque instant ja Position du piston distri- buteur 7. The cams 23 and 26 are desmodromic, that is to say they have conjugate profiles, so as to communicate to the levers 24 the same law of movement around the crank pin 9, so as to define strictly at each instant the position of the distributor piston 7.

T'oute rotation de 1'arbre 8 provoque un deplacement du centre d'articulation des leviers 24 suivant 1e rayon d'excentricité R (fng. 4) du maneton 9. Ce deplacement pro- voque une course de 1'organe mobile 7, egale ä C (fig 3), qui fait vagier 1e volume de la chambre de combustion sans modifier sa forme genegale. Any rotation of the shaft 8 causes a displacement of the center of articulation of the levers 24 along the first radius of eccentricity R (fng. 4) of the crank pin 9. This displacement causes a stroke of the movable member 7, equal to C (fig 3), which makes the volume of the combustion chamber vary without modifying its genegal shape.

Le rayon d'excentricité (R) est calcule de façon que la chambre de combustion ait an volume convenable pour 1e depart du moteur. The radius of eccentricity (R) is calculated so that the combustion chamber has a suitable volume for the start of the engine.

L'arbre 8 est commandé par un levier 14 qu'un dispositif de verrouillage 15, 16, 16', 17 bloque dans les deux positions correspon- dant au démarrage et ä 1a marche de r6gime. Ces deux positions de blocage du levier 14. celle de depart et celle de regime normal, sollt etablies de façon que dans chacune d'elles Faxe du maneton 9, donc laxe de pivotement dbz leviers 24, se trouve ä la même distance de faxe de rotation 27 des cames 23 et 26, afin que la commande reste desmodromique. The shaft 8 is controlled by a lever 14 which a locking device 15, 16, 16', 17 locks in the two positions corresponding to starting and running. These two locking positions of the lever 14, that of departure and that of normal mode, sollt established so that in each of them the axis of the crankpin 9, therefore the axis of pivoting of the levers 24, is at the same distance from the axis of rotation 27 of the cams 23 and 26, so that the control remains desmodromic.

Le leger déréglage de la distribution qui résulte de 1'augmentation du recouvrement de 1'ouverturss d'échappement 18, par 1'organe mobile 7, n'a pratiquement aucune influence sur la marohe du, moteur ä viee Pendant le demarrage. La course de l'orgaue 7, comme piston distributeur, influencé par les cames, se fait tont aussi bien dann 1e cas de la forte compression quo dans 1e cais du régime normal. The slight timing misadjustment which results from the increase in the covering of the exhaust opening 18 by the movable member 7 has practically no influence on the operation of the engine for life during starting. The stroke of the organ 7, as a distributor piston, influenced by the cams, takes place both in the first case of high compression and in the first case of the normal regime.

Claims

CLAIM Internal combustion engine, with compression ignition and variable compression, characterized by a member able to slide in the cylinder and forming the bottom of the latter, and by a shaft whose axis of rotation is fixed with respect to the cylinder and to which sollt transmitted leg Compression and combustion pressures acting on the sliding member, this shaft having an eccentric pin connected to said sliding member so that by rotating this shaft it moves the sliding member longitudinally in the cylinder, a mechanism allowing this shaft to be locked in dleux positions for each of which the volume of the combustion chamber has a different value. SUB-CLAIMS 1. Combustion engine according to claim, characterized in that at one end of the eccentric crankpin shaft is fixed a control lever by means of which an angular displacement of approximately 180 can be made. to this shaft, a locking device being arranged to lock said laver in its two extreme positions.

2. Combustion engine according to claim and sub-claim 1, characterized in that the connection between the eccentric pin of the shaft and the sliding member is achieved by means of a slider articulated on this eccentric pin. and sliding in a slide formed in an outer extension of said sliding member.

3. Engine ä. combustion according to claim and sub-claim 1, in which the sliding member forming the bottom of the cylinder works as a distributor piston and is controlled by besmodromic cams, driven by the engine and actuating a elbow connected to the sliding member by a connecting rod so as to form a toggle joint, characterized in that the elbow lever pivots on the crankpin of the shaft with eccentric crankpin, the two locking positions of which are such that in these two positions the axis of ma.neton is at the same distance from the axis of rotation of said ca: my.