FR2869647A1 - Cylinder block for internal combustion engine, has two longitudinal sides situated on sides of cylindrical bore, where each longitudinal side includes two longitudinal reinforcement lines with each line constituted of double wall - Google Patents

Abstract

The block has two longitudinal sides situated on sides of a cylindrical bore (3), where each longitudinal side comprises of two longitudinal reinforcement lines (5, 15). Each line is constituted of a double wall with a split located on a partition forming the corresponding longitudinal side. The double walls have thickness in the order of 4 to 5 millimeters and are spaced at a distance between 15 to 30 millimeters. An independent claim is also included for an internal combustion engine comprising a cylinder block.

Description

Cylinder block and engine comprising such a cylinder block

  The invention relates to an internal combustion engine cylinder block and to an engine comprising such a cylinder block.

  The invention more particularly relates to a cylinder block comprising, an upper part comprising a plurality of cylindrical bores aligned in a longitudinal direction, a water envelope surrounding them, and a lower part, such as a skirt, delimiting a volume for a crankshaft mechanism.

  The combustion noises radiated by an internal combustion engine are functions of this combustion (which is the excitatory phenomenon) and the dynamic response (vibrations) of the Moto-Propulsion Group to this excitation.

  Engines are subject to increasingly stringent pollution standards that are very restrictive for the development of combustion. As a result, the potential for reducing combustion noise by developing the combustion itself is increasingly reduced.

  For this reason, it is known to propose engine architecture modifications to better control its acoustic radiation. The known solutions are, however, unsatisfactory in terms of noise reduction generated by the engine and / or involve complex architectural modifications often incompatible with large-scale production.

  An object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.

  To this end, the cylinder block according to the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that at least one of the two longitudinal faces of the cylinder block comprises at least at least one longitudinal reinforcing line comprising a double wall.

  Furthermore, the invention may comprise one or more of the following features: the double wall is formed by local splitting of the wall of the cylinder block forming the longitudinal face; the two walls of the double wall are spaced apart; a distance of between about 15 and 30 mm, the longitudinal reinforcing line or lines extend over at least two-thirds, and preferably at least three-quarters, of the length of the longitudinal face, at least one of longitudinal faces comprises a longitudinal reinforcing line situated substantially at the level of the transition between its upper and lower portions of the cylinder block, at least one of the longitudinal faces comprises a longitudinal reinforcing line located substantially at mid-height of the lower part of the block -cylinders, - at least one of the longitudinal faces comprises a longitudinal reinforcing line located substantially at mid-height of the upper part the cylinder block, at least one of the two longitudinal sides of the cylinder block comprises at least one vertical reinforcing line comprising a double wall oriented in a direction substantially perpendicular to the longitudinal reinforcement line or lines, the spaces between the walls; split between the vertical and longitudinal reinforcement lines being communicating, the reinforcing line or lines have a width of between 3 and 20% of the height of the longitudinal faces, the space between the split walls of the line or lines of reinforcement communicates at least locally with the internal volume of the cylinder block, so as to allow the transit of crankcase gas.

  The invention also relates to an internal combustion engine comprising a cylinder block according to any one of the preceding characteristics.

  Other particularities and advantages will appear on reading the description below, with reference to the figures in which: FIGS. 1 and 2 respectively represent perspective views illustrating the two longitudinal faces of a cylinder block according to FIG. 3 and 4 respectively show perspective views of the cylinder block of FIGS. 1 and 2 transversely cut along two distinct transverse planes; FIGS. 5 and 6 respectively represent two perspective views of an example; arrangement of foundry cores adapted to allow the molding of the cylinder block of FIG. 1; FIG. 7 is a perspective view of a detail of the arrangement of FIG. 6 illustrating a circulation circuit of the Figure 8 shows a view similar to that of Figure 7 illustrating an alternative embodiment of the crankcase circulation circuit.

  - Figure 9 shows a perspective view of a cylinder block according to another embodiment of the invention and a foundry core used in its manufacture.

  Figures 1 to 4 illustrate a cylinder block 1 of an internal combustion engine according to a first embodiment.

  Conventionally, the cylinder block 1 comprises an upper portion 2 having a plurality of vertical cylindrical bores 3 which are aligned in a longitudinal direction. The bores 3 delimit the engine cylinders intended to accommodate pistons. A water jacket 3 is formed in the upper part so as to surround the bores 3 (see Figures 3 and 4).

  The cylinder block 1 also includes a lower portion 4, such as a skirt, and defining a volume for a crankshaft mechanism (not shown).

  Preferably, the upper 2 and lower 4 parts are made of a metallic material and are molded integrally. The bloccylindres 1 has, for example, a parallelepipedic general shape.

  The cylinder block 1 is delimited vertically by an upper face (intended to accommodate a cylinder head not shown), and a lower face (intended to accommodate an oil pan for example). The bloccylindres 1 is delimited laterally by two longitudinal faces located on either side of the alignment of the cylindrical bores 3 and two transverse faces. The longitudinal faces are sometimes called respectively "intake face" and "exhaust face", with reference to the path of the fresh gases and burned relative to the cylinders.

  In the exemplary embodiment of the invention shown in FIGS. 1 to 4, each of the longitudinal faces of the cylinder block 1 comprises two longitudinal reinforcing lines 5, 15. Each line 5, 15 of longitudinal reinforcement consists of a double wall. That is to say, the double wall 5, 15 consists of a localized splitting of the wall of the cylinder block 1 forming the longitudinal face.

  For example, the two walls of the double wall 5, 15 have a thickness of the order of 4 to 5 mm and are spaced apart by a distance of between 15 and 30 mm approximately. The distance between two adjacent double walls may be between 4 and 80 mm for example. In addition, the reinforcing lines 5, 15 have a width of, for example, between about 3 and 20% of the height of the longitudinal faces (width of, for example, between 30 and 80 mm).

  The reinforcement lines 5, 15 are preferably parallel to the alignment direction of the cylindrical bores 3. More precisely, the reinforcement lines 5, 15 are preferably parallel to the upper and lower faces of the cylinder block 1.

  The reinforcement lines 5, 15 preferably extend continuously over substantially the entire length of the longitudinal faces of the cylinder block 1. However, these reinforcement lines 5, 15 can extend continuously over two-thirds, and preferably at least three quarters of the length of the longitudinal face. In this case, the longitudinal reinforcing lines 5, 15 are preferably centered on the median part of the longitudinal face. That is, the middle portion of the reinforcing line 5, coincides substantially with the middle portion of the longitudinal face of the cylinder block 1.

  On each longitudinal face, a first longitudinal reinforcing line 15 is located substantially at the level of the transition between its upper and lower portions 4 of the cylinder block 1. That is, the first reinforcing line 15 is located at the connection between the drums (cylinders 3) and the skirt of the engine. This first line 15 longitudinal reinforcement allows better connection between the upper 2 and lower 3 parts of the cylinder block 1 and improves the behavior thereof when subjected to torsion forces.

  The second reinforcing line 5 of each longitudinal face is situated substantially at mid-height of the lower portion 4 of the cylinder block. This second reinforcement line 5 imparts better transverse rigidity to the skirts, thus improving their bending behavior.

  The invention thus allows a structural strengthening of the cylinder block 1 and a reduction of noise radiated by the engine when it is subjected to torsional and / or bending forces. In particular, when the cylinder block 1 is subjected to vibratory excitations between 800 and 3000 Hz, the noise generated by the vibration of the block 1 are reduced by 2 to 3dB with respect to the known cylinder blocks. Noise attenuation is particularly important around frequencies between 2500 and 2700 Hz and between 1000 and 1800 Hz.

  As can be seen in FIG. 3, the longitudinal faces may also comprise several vertical reinforcement lines 6 arranged regularly along the longitudinal faces of the cylinder block 1. The vertical reinforcing lines 6 are oriented from bottom to top on the block cylinders substantially perpendicular to longitudinal lines 5, 15 of reinforcement.

  As before, the vertical reinforcement lines 6 consist of double walls. The spaces between the double walls of the vertical and longitudinal reinforcement lines 6, 15 are preferably communicating.

  The vertical reinforcing lines 6 participate in the stiffening of the cylinder block 1 by creating a mesh of lines 5, 15, 6 of reinforcement. However, the presence of the vertical lines 6 is optional. Indeed, the main advantage of the presence of the vertical lines 6 lies in the possibility of providing a single molding core 105 to form all the lines 5, 15, 6 for reinforcing a face of the cylinder block 1, such as described in more detail below.

  FIG. 5 represents, in fact, an example of an arrangement of several cores that can be implemented in a molding process of the bloccylindres 1 of FIGS. 1 and 2.

  For the sake of simplification, the various cores are designated in Figure 5 by the same reference numerals as the parts of the bloccylindres 1 to which they give birth after casting of the metal.

  The arrangement conventionally comprises one or more central cores 7 defining the cylinders 3 and the inside 7 of the cylinder block 1. In its upper part, two cores 4 arranged on either side of the cylinder cores 3 define the chambers of water for a coolant. Two substantially vertical cores 8 forming passages for the lowering of the engine lubricating oil are arranged respectively at the two ends of the arrangement. The cores 8 forming passages for the descent of the lubricating oil are placed at the places corresponding to the two transverse faces of the cylinder block 1.

  Finally, a core 105 forming the reinforcing lines 5, 15, 6 is attached to each of the longitudinal faces of the housing cores 7, substantially at the portion forming the skirt of the cylinder block. Each of these cores 105 comprises two longitudinal lines 5, 15 connected by five vertical struts 6 defining the vertical reinforcements.

  The cores 105 forming the reinforcing lines 5, 15, 6 preferably rest on the central core 7 of the cylinder block via connecting pins ("plug") which create a junction between the space inside. double walls and the inside of the cylinder block 1 (pins not visible in Figure 5). For example, the face of the core 5, 15, 6 of reinforcement reported on the central core 7 comprises pins pin-shaped connection.

  Figures 5 and 6 illustrate two similar views of the same arrangement in two opposite directions. One end of the arrangement further comprises a core 9 defining a settling and filling volume connected to the core 8 of adjacent oil descent.

  FIG. 7 illustrates in an enlarged manner the conventional arrangement of the oil-down core 8 and the settling core 9. The rise of the crankcase gases is generally carried out via the volume defined by the settling core 10 (arrow F, FIG. Figures 6 and 7). Crankcase gases are the gases from bypassing the pistons, the latter also known as "blow-by" gases.

  In such an arrangement, to reach the settling volume 9, the crankcase gases must circulate longitudinally inside the cylinder block 1 passing below and on either side of the bearing caps (not shown). This circulation brakes the crankcase gases which consequently tend to go up directly via the oil downspouts. But the rise of the gases in the descents 8 oil impairs the good flow of oil from the cylinder head down.

  In an advantageous embodiment of the invention, the space between the doubled walls of the reinforcement lines 5, 15, 6 communicates with the internal volume of the cylinder block 1 (i.e. the cores 105 of reinforcement communicate with the central casing core 7 at the connections).

  In this way, the intermediate space of the double walls 5, 15, 6 constitutes a preferred circulation route for the crankcase vapors. The space between the double walls can therefore be used to ensure the rise of these gases. Thus, as shown in Figure 8, it is possible to overcome the core 9 defining a settling volume and filling connected to the core 8 of adjacent oil descent.

  Indeed, the crankcase gases can thus flow to the cylinder block inward of the double walls. These gases then circulate inside the double walls 5, 15, 25 as symbolized by the arrows C, to an outlet (arrow F) which will be connected to a decanting device (not shown).

  This embodiment thus has many advantages. Indeed, in addition to the fact of getting rid of a core in the manufacturing process of the cylinder block 1, this solution improves the flow of crankcase gases in the engine due to the increase in the volume of exchange between the cylinders and the volume dedicated to the circulation of gases. The circulation of gases in the descents of oil is thus reduced.

  Of course, the invention is not limited to the embodiments described above. In particular, the number and arrangement of the reinforcement lines is not limited to the embodiment described above. Thus, for example, a cylinder block having a single reinforcing line on a single longitudinal face (or on each of its longitudinal faces) is also within the scope of the invention.

  Similarly, and as shown in Figure 9, it is possible to provide a third reinforcement line on one or both longitudinal sides of the engine 1. The cylinder block 1 shown in Figure 9 differs from that described above only in that it comprises a third longitudinal reinforcing line. For the sake of simplification, the elements identical to those described above are designated by the same reference numerals and will not be described a second time. The third longitudinal reinforcing line is situated substantially at mid-height of the upper portion 2 of the bloccylindres 1 (that is to say substantially halfway up the cylindrical bores 3).

  Figure 9 also illustrates a reinforcing core for providing the cylinder block 1 with three longitudinal reinforcing lines 5, 15, 25. The three longitudinal reinforcing lines 5, 15, 25 of the core are connected by vertical reinforcement lines 6 so as to form a mesh.

  The cylinder block 1 according to the configuration of Figure 9 has a stiffness further improved over the prior art. In particular, the architecture according to FIG. 9 allows vibration noise reductions of the order of 3 to 5 dB relative to the prior art.

  Finally, the molding process of the cylinder block 1 according to the invention is not limited to the example described above. Thus, for example, the cores 5, 15, 25, 6 attached to the central core 7 can be replaced by simple longitudinal protuberances formed directly on the central core 7 of the cylinder block. he

Claims (11)

CLAIMS,   A cylinder block (1) of an internal combustion engine comprising an upper part (2) having a plurality of cylindrical bores (3) aligned in a longitudinal direction and a water jacket (3) surrounding them, a part lower part (4) such as a skirt and delimiting a volume for a crankshaft mechanism, the cylinder block (1) having two longitudinal faces located on either side of the alignment of the cylindrical bores (3), characterized in that at least one of the two longitudinal faces of the cylinder block (1) comprises at least one longitudinal reinforcing line (5, 15, 25) comprising a double wall.   2. cylinder block (1) according to claim 1, characterized in that the double wall (5, 15, 25) is formed by a local resolution of the wall of the cylinder block (1) forming the longitudinal face.   3. Cylinder block (1) according to claim 1 or 2, characterized in that the two walls of the double wall are spaced apart by a distance of between about 15 and 30 mm.   4. cylinder block (1) according to any one of the preceding claims, characterized in that the or lines (5, 15, 25) longitudinal reinforcement extend over at least two thirds, and preferably at least three quarters, of the length of the longitudinal face.   5. Cylinder block (1) according to any one of the preceding claims, characterized in that at least one longitudinal face comprises a longitudinal reinforcing line (15) situated substantially at the level of the transition between its upper parts (2). ) and lower (4) of the cylinder block (1).   6. cylinder block (1) according to any one of the preceding claims, characterized in that at least one longitudinal face comprises a longitudinal reinforcing line (5) located substantially at mid-height of the lower part (4). of the cylinder block (1).   7. Cylinder block (1) according to any one of the preceding claims, characterized in that at least one longitudinal face comprises a longitudinal reinforcing line (25) situated substantially at mid-height of the upper part (2). of the cylinder block (1).   8. cylinder block (1) according to any one of the preceding claims, characterized in that at least one of the two longitudinal sides of the cylinder block (1) comprises at least one line (6) of vertical reinforcement comprising a double wall oriented in a direction substantially perpendicular to the longitudinal reinforcing line or lines (5, 15, 25), and in that the spaces between the split walls of the vertical and longitudinal reinforcement lines (5) (5, 15, 25) are communicating.   9. cylinder block (1) according to any one of the preceding claims, characterized in that the or lines (5, 15, 25) of reinforcement have a width of between 3 and 20% of the height of the longitudinal faces .   10. cylinder block (1) according to any one of the preceding claims, characterized in that the space between the split walls of the or lines (6) of reinforcement (5, 6, 15, 25) communicates at least locally with the internal volume of the cylinder block, so as to allow the transit of crankcase gas.   11. Internal combustion engine characterized in that it comprises a bloccylinder according to any one of the preceding claims.