GB2318615A

GB2318615A - Venting device for a crankcase of an internal combustion engine

Info

Publication number: GB2318615A
Application number: GB9722113A
Authority: GB
Inventors: Helmut Kronowiecki; Gernot Langer; Erhard Rau; Klaus Bruchner; Ralf Kaufmann
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1996-10-26
Filing date: 1997-10-20
Publication date: 1998-04-29
Anticipated expiration: 2017-10-20
Also published as: DE19644526C2; FR2755180B1; GB2318615B; GB9722113D0; ITRM970632A1; DE19644526A1; FR2755180A1; IT1295817B1

Abstract

A venting device for a crankcase 2 of a internal combustion engine has a venting conduit 9, through which the venting gases from the crankcase 2 are supplied to an oil separator 7 and to an intake system of the internal combustion engine. An oil return duct 10 to 16, which runs in a side wall of the crankcase and through which oil separated in the oil separator 7 is returned into a oil sump 5, forms, along its run, a syphon which has two ducts 15, 16, running essentially in the direction of a vertical axis 17 of the internal combustion engine, and a connecting duct 14. The crankcase 2 has an upper part 3 and a lower part 4, and at least the connecting duct 14, 14' is arranged in the crankcase lower part 4. The invention allows simple and cost-effective production with minimum outlay in terms of constructional space and number of parts.

Description

2318615 Venting device for a crankcase of an internal combustion engine

The invention relates to a venting device for a crankcase of an internal combustion engine.

MTZ Motortechnische Zeitschrift [MTZ Engine Journal] 53 (1992) 10, pages 430-442, discloses a venting device for a crankcase of an internal combustion engine, the said crankcase being closed off downwards by an oil sump. In a reciprocating-piston engine, so-called venting gases are generated, consisting of blow by gases which occur during the compression stroke and combustion stroke and which entrain oil mist when they flow through the crankcase. The venting device serves for discharging these venting gases out of the crankcase and thereby prevents the build-up, in the crankcase, of an increasing gas pressure which could lead to a failure of the internal combustion engine. Here, the venting device has a venting conduit which runs in a side wall of the crankcase and which supplies the venting gases to an oil separator flanged on the side wall of the crankcase, the oil particles of the venting gases precipitating in the oil separator and the deoiled ventin g gases subsequently being introduced into the intake system of the internal combustion engine. There extends from this oil separator an oil return duct which likewise runs in the side wall of the crankcase and through which the separated oil particles are supplied to a separate syphon which is arranged at the end of the oil return duct and projects with its two ducts and their connecting duct into the oil sump.

For the general technical background, reference is also made to EP 0,600, 341 AI and DE 42 39 108 AI.

The present invention seeks to design a venting device in such a way that simple and cost-effective production becomes possible, along with as low an outlay as possible in terms of constructional space and a minimum number of parts.

According to the present invention there is provided a venting device for a crankcase of an internal combustion engine, with a venting conduit, through which venting gases from the crankcase are supplied to an oil separator and to an intake system of the internal combustion engine, furthermore with an oil return duct which runs in a side wall of the crankcase and through which oil separated in the oil separator 2 is returned into an oil sump, the oil return duct forming, along its run, a syphon which has two ducts, running essentially in the direction of a vertical axis of the internal combustion engine when in the installed position, and a connecting duct, wherein, the crankcase has a crankcase upper part and a crankcase lower part, and at least the connecting duct is arranged in the crankcase lower part.

An essential advantage of the venting device according to the invention is that it is simple to produce. The venting conduit and the oil return duct can be produced by casting without subsequent machining in the crankcase. Since the oil return duct forms a syphon along its run, a separate component can be dispensed with, with the result that there is no need for additional installation space in the crankcase or even in the oil sump.

In an embodiment of the invention the syphon runs essentially over the entire height of the crankcase lower part which makes it possible to have a sufficient length of the syphon, in which the oil running off collects and an oil column forming a liquid barrier builds up, the said oil column preventing the venting gases from flowing through the oil return duct undesirably.

The flange of the oil sump advantageously forms a cover for the syphon orifice, so that a separate closure for the syphon orifice can be dispensed with. This region is sealed off via the seal which is required in any case between the oil sump and the crankcase.

The duct of the syphon advantageously has, on a side facing away from the venting conduit, a V-shaped recess for the overflow of the oil running off, with the result that the oil particles are not entrained again by the venting gases.

Two exemplary embodiments of the invention are explained in more detail below, along with further particulars, in five drawings in which:

Fig. 1 shows a first exemplary embodiment in a view of a part region of a side wall of a crankcase of an internal combustion engine, the said crankcase comprising a crankcase upper part and a crankcase lower part and being closed off downwards by an oil sump, with a venting device according to the invention which is illustrated in part section, Fig. 2 shows a section through the part region of the crankcase side wall along the line 3 II-II from Fig. 1, with an assembly carrier which is flanged onto the side wall of the crankcase and into which an oil separator is integrated, Fig. 3 shows a section through the part region of the crankcase side wall along the line III-III from Fig. 1, Fig. 4 shows a top view of the crankcase lower part from Fig. 1, and Fig. 5 shows a second exemplary embodiment in a cross-section through a part region of the crankcase with a venting device according to the invention and with the flanged-on assembly carrier.

Fig. 1 shows a detail of a side wall 1 of a crankcase 2 of an internal combustion engine in the installed position, with a venting device according to the invention illustrated in part section, in a first exemplary embodiment.

The crankcase 2 comprises a crankcase upper part 3 and a crankcase lower part 4 and is closed off downwards by an oil sump 5 likewise only partially illustrated. An assembly carrier 6 with integrated oil separator 7 is flanged onto the side wall 1 of the crankcase 2 (see Fig. 2), the said carrier bearing sealingly against flange regions 8 of the crankcase upper part 3 which are illustrated in the drawing.

The venting device is arranged in the crankcase upper part 3 and in the crankcase lower part 4 and has a venting conduit 9 which is connected via the oil separator 7 to an oil return duct designated as a whole by 10. The oil return duct 10 is divided into an oil collecting space 11 (see Fig. 2), a duct region 12, a connecting groove 13 and two ducts 15 and 16 connected via a connecting duct 14. The venting conduit 9, illustrated more clearly in Fig. 2, is arranged in the crankcase upper part 3 and has a transitional space 9a which adjoins the oil separator 7.

Fig. 2 illustrates the assembly carrier 6 flanged onto the side wall 1 of the crankcase 2 and having the integrated oil separator 7. The assembly carrier 6 serves for fastening a water pump, an air-conditioning compressor and a dynamo, the said fastening not being illustrated. The oil separator 7 has an oil separation space 23 with a rib 24, the said space overlapping the transitional space 9a of the venting conduit 9 and the oil collecting space 11 of the oil return duct 10.

As shown in Fig. 2, the oil separator 7 is connected to the remaining oil return duct 10 via the oil collecting space 11 arranged in the crankcase upper part 3.

4 The oil return duct 10 has, adjoining the oil collecting space 11, the duct region 12 which runs in the crankcase upper part 3 essentially in the direction of a vertical axis 17 of the internal combustion engine and which opens into a syphon via the connecting groove 13 extending in the direction of a longitudinal axis 18 of the internal combustion engine (see also Fig. 4).

The syphon illustrated in Fig. 1, which is arranged in the crankcase lower part 4, comprises the two ducts 15 and 16, running essentially in the direction of the vertical axis 17 of the internal combustion engine, and the connecting duct 14, with the result that the syphon runs essentially over the entire height h of the crankcase lower part 4.

The duct 15 adjoining the connecting groove 13 has, in an upper region 15a, a lateral extent which runs in the direction of a transverse axis 19 of the internal combustion engine (see Fig. 4) and which narrows in a region 15b towards the oil sump 5. According to Figs. 1 to 3, an orifice 20 of the syphon, the said orifice being formed by the ducts 15, 16 and the connecting duct 14 and facing the oil sump 5, is covered by a flange 21 of the oil sump 5. The orifice 20 is sealed off via the seal of the oil sump 5 relative to the crankcase 2.

As illustrated in Fig. 3, the duct 16 adjoining the connecting duct 14 has an upper region 16a which a narrowed region 16b adjoins. The duct 16 is open towards the crankcase upper part 3 and has, on a side facing away from the venting conduit 9, a V-shaped recess 22, by means of which it becomes possible for the oil running off to overflow easily.

The venting conduit 9 with transitional space 9a and the entire oil return duct with all part regions 11 to 16 are designed in such a way that they can be at least precast in a casting process by means of a slide. In the present exemplary embodiments, the venting device is already finish-cast in the crankcase 2.

The venting gases, which, in a reciprocating-piston engine, are generated during the compression stroke and combustion stroke and which consist of blow-by gases and oil mist, are supplied from the crankcase 2 through the venting conduit 9, via the transitional space 9a of the latter, to the oil separation space 23 of the oil separator 7. Oil particles entrained in the stream of venting gases impinge onto the rib 24 arranged in the oil separation space 23, are precipitated there and flow off into the oil collecting space 11. The deolled venting gases are supplied (marked by an arrow in Fig. 2) to an intake system, not illustrated here, of the internal combustion engine, the said intake system being arranged so as to adjoin the oil separator 7. The oil separated in the oil separation space 23 at the rib 24 is supplied via the oil collecting space 11 to the remaining oil return duct 10 with its further part regions 12 to 16. In order to avoid a bypass of the venting gases through the oil return duct 10, the latter forms, along its run, a syphon, in which the oil running off from the oil separator 7 accumulates and, as a result of the pressure difference between the crankcase 2 and the intake side of the oil separator 7, an oil column forming a liquid barrier builds up (see the oil levels illustrated in Figs. 1 and 2), the said oil colun-in preventing the venting gases from flowing through the oil return duct 10 undesirably. The oil flowing after overflows via the V- shaped recess 22 of the duct 16 on a side located opposite the venting conduit 9, so that no oil particles can be entrained again by the venting gases, and subsequently drops into the oil sump 5.

Fig. 5 shows a second exemplary embodiment of the venting device according to the invention of a crankcase 2. Like components from the first exemplary embodiment are designated by the same reference symbols. The syphon, formed along the run of the oil return duct 10' by the ducts 15', 16' and the connecting duct 14', runs essentially in the crankcase upper part 3. The ducts 15', 16' of the syphon are arranged in the crankcase upper part 3 and open into a transverse duct 25' which runs in the direction of the transverse axis 19 of the internal combustion engine and which, on one side, is closed by means of the flanged-on assembly carrier 6 and, on the other side facing the interior of the crankcase 2, forms an oil run-off. Only the connecting duct 14' runs in the crankcase lower part 4.

In the second exemplary embodiment, the path of the venting gases into the oil separation space 23 of the oil separator 7 corresponds to the above-described path from the first exemplary embodiment. Only the path of the oil particles, separated in the oil separator 7, through the oil return duct 10' into the oil sump 5 is different. The oil passes from the oil separation space 23 directly into the syphon, arranged mainly in the crankcase upper part 3, and from the said syphon into the transverse duct 1 6 25'. The oil overflows on a side of the transverse duct 25', the said side facing the interior of the crankcase 2, and drops into the oil sump 5.

7

Claims

1. A venting device for a crankcase of an internal combustion engine, with a venting conduit, through which venting gases from the crankcase are supplied to an oil separator and to an intake system of the internal combustion engine, furthermore with an oil return duct which runs in a side wall of the crankcase and through which oil separated in the oil separator is returned into an oil sump, the oil return duct forming, along its run, a syphon which has two ducts, running essentially in the direction of a vertical axis of the internal combustion engine when in the installed position, and a connecting duct, wherein, the crankcase has a crankcase upper part and a crankcase lower part, and at least the connecting duct is arranged in the crankcase lower part.

2. A venting device according to Claim 1, wherein the syphon runs substantially over the entire height of the crankcase lower part.

3. A venting device according to Claim 1 or 2, wherein an orifice of the syphon, the said orifice facing the oil sump, is covered by a flange of the oil sump.

4. A venting device according to any one of Claims 1 to 3, wherein the duct of the syphon has, on a side facing away from the venting conduit, a Vshaped recess for the overflow of the oil running off.

5. A venting device according to any one of Claims 1 to 4, wherein the ducts of the syphon are arranged in the crankcase upper part.

6. A venting device according to any one of Claims 1 to 5, wherein the oil return duct is at least precast in the crankcase.

7. A venting device according to Claim 1, wherein the oil separator is integrated into an assembly carrier fastened to the crankcase.

8. A crankcase of an internal combustion engine, with a venting device substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

8 8. A venting device for a crankcase of an internal combustion engine, substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

Amendments to the claims have been filed as f6Omm Claims 1 A crankcase of an internal combustion engine, with a venting device, having a venting conduit, through which venting gases from the crankcase are supplied to an oil separator and to an intake system of the internal combustion engine, furthermore with an oil return duct which runs in a side wall of the crankcase and through which oil separated in the oil separator is returned into an oil sump, the oil return duct forming, along its run, a syphon which has two ducts, running essentially in the direction of a vertical axis of the internal combustion engine when in the installed position, and a connecting duct, wherein, the crankcase has a crankcase upper part and a crankcase lower part, and at least the connecting duct is arranged in the crankcase lower part.

2. A crankcase of an internal combustion engine, with a venting device according to Claim 1, wherein the syphon runs substantially over the entire height of the crankcase lower part.

3. A crankcase of an internal combustion engine, with a venting device according to Claim 1 or 2, wherein an orifice of the syphon, the said orifice facing the oil sump, is covered by a flange of the oil sump.

4. A crankcase of an internal combustion engine, with a venting device according to any one of Claims 1 to 3, wherein the duct of the syphon has, on a side facing away from the venting conduit, a V-shaped recess for the overflow of the oil running off.

5. A crankcase of an internal combustion engine, with a venting device according to any one of Claims 1 to 4, wherein the ducts of the syphon are arranged in the crankcase upper part.

6. A crankcase of an internal combustion engine, with a venting device -to- according to any one of Claims 1 to 5, wherein the oil return duct is precast substantially in the crankcase.

7. A crankcase of an internal combustion engine, with a venting device according to Claim 1, wherein the oil separator is integrated into an assembly carrier fastened to the crankcase.