EP0466542A1 - Cylinder block for an engine comprising a carter vapour evacuation and oil recycling circuit - Google Patents

Abstract

The invention relates to a casing or cylinder block for an internal combustion engine of any type, for example of the V-cylinder or in-line type. This upper casing (1) has internal conduits (7, 8) which connect the upper part (143) of the casing to lower compartments (5) separating crankshaft bearings (12), these conduits allowing the evacuation of gases from the crankcase and recycling of engine oil and opening into a flattened chamber (9), this chamber and the internal conduits forming a circuit (C) from the foundry. The invention is particularly applicable to the automotive industry. <IMAGE>

Description

The present invention relates to an upper casing or cylinder block for any internal combustion engine, for example of the V-cylinder or in-line type.

During the operation of an internal combustion engine, there is leakage of combustion gases at the piston segmentation, which results in the presence of unused gas in the crankcase. These gases from the crankcase must be evacuated in order to avoid any increase in pressure in the crankcase. Furthermore, it is also desirable to recycle the engine oil which is supplied to the cylinder head to the sump, in particular for the lubrication of the valves.

To do this, upper casings have been proposed in which internal conduits are made connecting the upper part of the casing facing the cylinder head to lower compartments which separate the crankshaft bearings, in order to allow the evacuation of gases from the casing and the engine oil recycling.

However, the internal conduits of the prior art are of complex shape, and have small gas and oil passage sections. In addition, these conduits are obtained by machining or with the aid of foundry pins or fragile molding cores, so that the casings thus produced are expensive and insufficiently rigid.

Also, the object of the present invention is to remedy these drawbacks by proposing an upper casing with internal ducts for discharging the gases from the casing and for recycling the engine oil which are of simple shape. and large passage sections, and which, moreover, can be produced at a lower cost, while increasing the rigidity of the casing, thanks to the use of a unique and resistant molding core.

To this end, the subject of the invention is an upper cylinder head casing for any internal combustion engine, such as of the V-cylinder or in-line type, and comprising internal conduits which connect the upper part of the casing to compartments separating the crankshaft bearings, these conduits allowing the evacuation of gases from the crankcase and the recycling of engine oil, this crankcase being characterized in that said internal evacuation and recycling conduits open into a flattened chamber, arranged near the lower compartments and crossed perpendicularly by the cylinders, said chamber and said internal conduits forming a circuit from the foundry.

The invention is further characterized in that the circuit includes gas passages from the casing which connect the aforementioned chamber to each of the lower compartments.

The upper casing is further characterized in that internal oil recycling conduits extend substantially parallel to the cylinders and respectively connect the circuit chamber to a mounting plane of a cylinder head and to an opposite lower face of the casing, these conduits being offset from each other.

It will also be specified here that, for an engine whose cylinders are arranged in two V-shaped lines, the circuit chamber has the shape of a dihedral, with a central or edge part which is connected to conduits internal extending between the two lines of cylinders and opening onto a face of the casing provided for mounting a gas treatment member of the casing.

The invention is further characterized in that cooling chambers are formed around the cylinders for the circulation of a cooling liquid, the circuit chamber being located between the cooling chambers and the aforementioned lower compartments.

However, other advantages and characteristics of the invention will appear more clearly on reading the detailed description which follows and which refers to the appended drawings, given solely by way of example, and in which.

Figure 1 is a perspective view of an upper casing according to the invention, for an internal combustion engine of the V-cylinder type.

Figure 2 is a sectional view of the upper housing of Figure 1 and along the line II-II.

FIG. 3 illustrates in perspective the shape of the chamber and of the internal conduits which constitute the evacuation and recycling circuit according to the invention.

Referring first of all to FIG. 2, it can be seen that an engine M notably comprises an upper casing or cylinder block 1, a lower casing 2 and two cylinder heads 3a and 3b which are fixed to the upper cylinder head casing 1 .

Following the example illustrated in FIGS. 1 and 2, the engine M is of the type with 6 cylinders in V, that is to say comprises, on either side of a longitudinal plane XX ′ two lines of three cylinders 41 and 42. It is also noted that lower compartments 5 which separate transverse walls 11 (only one of which is visible in FIG. 1 and on FIG. 2) in which crankshaft bearings 12 are formed are produced in the upper casing 1 so as to open into a face forming a lower joint plane 13 against which the lower casing 2 is mounted.

Each cylinder 41, 42 opens on the one hand into the upper part 143 of the casing 1 and on the other hand into one of the lower compartments 5. The three aligned cylinders which are designated by the reference numeral 41 are produced on one side of the longitudinal plane XX ′ and open onto a joint plane 141 of the upper part 143, on which plane the cylinder head 3a is mounted. The other three cylinders 42 are produced in the casing 1 on the other side of the plane X-X ′ and lead to another joint plane 142 of the upper part 143, on which plane the cylinder head 3b is mounted.

It should be noted here that a jacket can be inserted into each cylinder 41, 42, for example during the molding of the upper casing 1.

There have been identified at 151, 152, two coolant supply conduits, produced in the casing 1 and which extend substantially parallel to a longitudinal direction of the casing 1. The supply conduits 151 and 152 are respectively connected to cooling chambers 161 and 162 which are formed around each cylinder 41, 42, so as to allow circulation of coolant in the casing 1.

Holes 171, 172 for communication of the cooling chambers 161 and 162 with the cylinder heads 3a and 3b open respectively in the joint planes 141 and 142. The coolant is introduced into the casing 1 via an opening 153 which opens into a transverse face 6 of the casing 1 and which extends substantially parallel to the transverse walls described above.

FIG. 2 shows a longitudinal channel 173 for circulation of pressurized oil which extends in the longitudinal direction of the casing 2, along the lower compartments 5.

The upper casing 1 also comprises internal conduits for discharging gas from the casing and for recycling the oil which will now be described, with further reference to FIG. 3.

In accordance with the invention, the upper casing 1 comprises internal pipes 7 for recycling engine oil and internal pipes 8 for evacuating the gases from the casing which open into a chamber 9, so as to form a circuit C coming from foundry with the casing 1 and shown in perspective in FIG. 3.

The chamber 9 of the circuit C is in the form of a flattened dihedron and extends near a top wall 51 of the lower compartments 5 of the casing 1. The chamber 9 is therefore constituted by two flattened and contiguous parts identified at 91 and 92 Each flattened part 91 and 92 of the chamber 9 is crossed substantially at right angles by the cylinders 41 and 42, respectively. A central part 93 of the chamber 9 forms an edge which extends in the longitudinal direction of the casing 1, right through the chamber 9.

Two evacuation conduits 8 of oblong section extend, between the cylinders 41, 42, from the upper part of the edge 93 to a central face 144 of the casing 1 which is provided for mounting a treatment (not shown) of the crankcase gases.

It is therefore understood that the chamber 9 of the circuit C formed in the upper casing 1, is located between the cooling chambers 161 and 162 and the lower compartments 5.

The recycling conduits 7 extend laterally from each free end of the flattened parts 91, 92 of the chamber 9, and consist of upper sections 7a and lower sections 7b.

According to the example illustrated, each flattened part 91, 92 of the chamber 9 comprises five upper sections 7a and three lower sections 7b, of oblong section. The upper sections 7a of the recycling conduits 7 are formed in the casing 1 so as to extend substantially parallel to the cylinder lines 41 and 42. These upper sections 7a are connected five to five, at their upper part, by channels 71 and 72 which open respectively in the joint planes 141 and 142. In FIGS. 1 and 2 it can be seen that each of the channels 71 and 72 is produced near a lateral flange 241, 242 of the joint planes 141 and 142 of the housing 1, and extend in a direction substantially parallel to the longitudinal direction of the housing.

The lower sections 7b of the recycling conduits 7 extend, from top to bottom along the side walls 52 of the compartments 5 which are parallel to the plane XX ′, from one of the flattened parts 91, 92 of the chamber 9 to the joint plane 13 against which the lower casing 2 is mounted.

It is already understood that the descent of the engine oil from the cylinder heads 3a, 3b is improved by the oblong section of the sections 7a, 7b and that, in addition, any emulsion of the oil is avoided since it is recycled at the level crankshaft bearings 12.

It can be seen in the figures that the upper sections 7a and the lower sections 7b of the recycling conduits 7 are offset from one another. In other words, the lower sections 7b are substantially parallel to the plane X-X ′ and therefore do not extend exactly in alignment with the upper sections 7a which are parallel to the cylinders 41, 42.

On the other hand, as can be seen in FIG. 3, the lower sections 7b open into the chamber 9 at locations which are not located exactly opposite the ends of the upper sections 7a which open into each flattened part 91, 92 of the chamber 9. Such a shift between the sections 7a and 7b makes it possible to "break" the flow of oil flow towards the lower casing 2, but also makes it possible to improve the evacuation of the gases by allowing the gases trapped in the oil from the lower sump 2 to escape through the lower sections 7b.

Near a lower part of the edge 93 of the chamber 9 are formed passages 94 which pass through the wall 51 to open into each compartment 5, so as to allow optimal evacuation of the gases from the casing using the conduits 8, and for example to a device for treating these gases. It is possible, thanks to such passages 94, to connect the various crankshaft mounting compartments 5, in order to improve the operation of the engine.

Thanks to the arrangement of pipes, chambers and passages of circuit C described above, the evacuation of gases from the casing is improved significantly, so that the engine M equipped with a circuit C offers less resistance to the movement of the moving parts such as pistons, connecting rods, etc.

There was therefore obtained according to the invention an upper cylinder head casing of inexpensive production, in which it is easy to produce gas evacuation and oil recycling conduits by interposing a one-piece molding core and of similar shape to the circuit visible in Figure 3 in the casting mold of the housing. Such a monobloc core is arranged during the preparation of the mold between the cores making it possible to obtain the cooling chambers and the cores defining the mounting compartments of the crankshaft.

In addition, the upper casing according to the invention has the advantage of being more rigid thanks to the different separation walls of the chambers and the conduits, which also has the result of improving the sound absorption of the casing.

It goes without saying that the circuit C described above and provided for an engine M of the V-cylinder type, can also be adapted to an engine of the in-line cylinder type, and that the number of conduits as well as the section of those -these can be adapted to the desired engine operating characteristics.

Of course, the invention is in no way limited to the embodiment which has just been described and which has was given as an example.

On the contrary, the invention includes all the technical equivalents of the means described and their combinations if these are carried out according to the spirit.

Claims (5)

Upper casing or cylinder block for any internal combustion engine, for example of the V-cylinder or in-line type, and comprising internal conduits (7, 8) which connect the upper part (143) of the casing (1) to lower compartments (5) separating the crankshaft bearings (12), these conduits (7, 8) allowing the evacuation of gases from the crankcase and the recycling of engine oil, characterized in that said internal evacuation conduits (8) and recycling (7, 7a, 7b) open into a flattened chamber (9), disposed near the lower compartments (5) and crossed perpendicularly by the cylinders (41, 42), said chamber (9) and said internal conduits (7, 7a, 7b, 8) forming a circuit (C) from the foundry. Upper cylinder head casing according to claim 1 characterized in that the circuit (C) comprises passages (94) for gas from the casing (1) which connect the aforementioned chamber (9) to each of the lower compartments (5). Upper cylinder head housing according to claim 1 or 2, characterized in that internal oil recycling conduits (7, 7a) extend substantially parallel to the cylinders (41, 42) and connect the chamber (9) of the circuit (C) to a joint plane (141, 142) for mounting a cylinder head (3a, 3b), and to a lower face (13) opposite the casing (1), these conduits being offset from each other to others. Upper casing according to one of claims 1 to 3 characterized in that, for an engine (M) whose cylinders (41, 42) are arranged in two lines in V, the chamber (9) of the circuit has the form of a dihedral (91, 92) with a central part or edge (93) which is connected to internal conduits (8) extending between the two lines of cylinders ( 41, 42) and opening onto a face (144) of the casing (1) provided for mounting a member for treating the casing gases. Upper casing according to one of claims 1 to 4, characterized in that cooling chambers (161, 162) are formed around the cylinders (41, 42) for the circulation of a cooling liquid, the chamber (9) of the circuit being located between the cooling chambers (161, 162) and the aforementioned lower compartments (5).

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