GB2441404A

GB2441404A - Baffle arrangement for separating liquid oil from blow-by gas in an i.c. engine

Info

Publication number: GB2441404A
Application number: GB0714054A
Authority: GB
Inventors: Richard Pateman; Stuart Wagstaff; Vivian Page
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2006-08-30
Filing date: 2007-07-19
Publication date: 2008-03-05
Anticipated expiration: 2027-07-19
Also published as: GB0714054D0; GB2441404B; GB0617071D0

Abstract

A baffle device 10 for separating liquid oil from blow-by gas 100 within an engine comprises a number of inclined baffle passages 30 having an inlet 20; a cleaned gas outlet 50; and a drain 40 for the separated liquid oil 110. The baffle device is provided at a horizontally central portion of the engine and comprises a funnel 44 and drain outlet 42 that are symmetrical about one or more vertical planes of the engine so that oil drainage is not affected by vehicle orientation. The inlet 20 has a larger diameter than the baffle passages 30 to reduce the velocity of blow-by gas entering the baffle device 10 so that some separated oil can flow back out via the inlet 20. The drain outlet has a restricted passage 48 so that oil only gradually leaks from it and thereby forms a barrier to the entry of blow-by gas. The gas outlet 50 may extend horizontally from the baffle device (fig.2) to save space vertically. The upper portion of the baffle device may be formed by the cylinder head cover.

Description

Baffle Arrangement

Technical Field

The present disclosure relates to apparatus for separating one phase from a multiphase fluid. In particular, but not exclusively, the disclosure relates to a baffle arrangement provided in the top cover of an internal combustion engine to limit the egress of liquid oil from the engine. * S * I..

Background * S*.

In use, an internal combustion engine has a specific orientation for *. 15 optimum functioning. The engine typically has at least two vertically arranged chambers: the lower crankcase; and the upper cylinder head cover. There may also be an intermediary timing case. Each of these * chambers must be openly connected to allow the free flow of bypass gases and air movement during engine running.

In the engine, blow-by gas can escape past the piston into the crankcase where it mixes with airborne oil droplets. It is possible to simply vent the blow-by gas to atmosphere. Alternatively, a closed breather system can be provided so that the blow-by gas is fed back into the engine induction system. This reduces the emission of unwanted gases.

It is desirable to include, in the breather system, means to retrieve oil contained in the blow-by gas and return this to the engine lubricating oil system for re-use. Otherwise the liquid oil, if allowed to enter the engine induction system (oil carry-over), can cause fouling of such components as turbocharger compressor vanes and engine poppet valves. Also, the liquid oil can form carbon deposits on the valves which can be detrimental to the performance of the intake air system. In addition, there will be a reduction in the volume of oil available for lubricating and cooling purposes.

It is known to provide a separator or baffle device in the cylinder head cover of the engine to impede oil carry-over. In conventional arrangements, the baffle, and a drain which is provided for the collected liquid oil, is provided at a horizontally peripheral portion of the engine.

This is because conventional arrangements are large and bulky, comprising of a number of separate components. Therefore, there is insufficient space, or assembly is more difficult, for mounting the device ** within a horizontally central portion of the engine. *.S.

A particular problem exists for the engines of off-road vehicles which are * often operated on terrain which is not level. If the drain is at a particular horizontally peripheral portion of the engine, and the vehicle is at an inclined angle such that this peripheral portion is at a greater vertical height than when the vehicle is level, then there will be inadequate drainage of the liquid oil. Put another way, inadequate drainage can occur whenever the drain is substantially offset from a horizontally peripheral portion of the engine. A similar problem occurs during acceleration or deceleration of the vehicle.

Also, many conventional arrangements, especially those for V-type engines, include passages, inlets and outlets which are oriented at an oblique angle (when the vehicle is level). These passages, inlets and outlets become more horizontal when the vehicle is at an inclined angle which can impair performance.

Furthermore, for a number of design reasons, prior art arrangements are typically asymmetrical about a vertical axis (when the vehicle is level).

This impairs the effectiveness of the arrangements when the vehicle is oriented at particular inclined angles to this vertical axis. For asymmetrical arrangements, the spatial relationship between the baffle and the drain will vary depending on the orientation of the vehicle.

Also, conventional arrangements often include baffle portions which are substantially horizontal (when the vehicle is level). These baffle portions represent sites where liquid oil can collect. The liquid oil can then be * * blown through the system by the gases to enter the induction system.

Conventional arrangements also often include baffle plate portions which are substantially vertical (when the vehicle is level). The thickness of these plate portions provide horizontal surfaces from which liquid oil may be suspended before being blown through the system by the gases to * enter the induction system.

Furthermore, the inlet aperture of conventional arrangements is often the same diameter to the baffle passages. In such case, the velocity of the gas entering the baffle passages can be great enough to inhibit collected liquid oil from draining back via the inlet aperture. The drain outlet can also be the same diameter to the baffle passages which can allow blow-by gas to bypass the baffle via the drain outlet and then enter the induction system.

Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided a baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; a gas outlet; and a drain passage for the separated liquid oil, wherein the baffle device is adapted such that, in use, the drain passage is provided at a substantially central portion of the engine.

According to a second aspect of the present disclosure, there is provided a baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; a gas outlet; and a drain passage for the separated liquid oil, wherein the baffle device is adapted to be, in use, substantially symmetrical about one or more vertical planes of the engine. *... *. **

: * According to a third aspect of the present disclosure, there is provided a baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; and means for reducing the velocity of blow-by gas entering the inlet.

According to a fourth aspect of the present disclosure, there is provided a baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; a gas outlet; and a drain passage for allowing the separated liquid oil to drain from the baffle device, the drain outlet including: means for preventing blow-by gas from entering the baffle device via the drain passage.

According to a fifth aspect of the present disclosure, there is provided an internal combustion engine including a baffle device in accordance with one of the first to the fourth aspects of the disclosure.

Brief Description of the Drawings

An embodiment of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: **5* * S Fig. I is a sectional end view of a first embodiment of the baffle device; * S * SI Fig. 2 is a sectional end view of a second embodiment of the baffle device; and *S5s * *

SI

: * * Fig. 3 is a sectional side view of the baffle device of Fig. 2.

Detailed Description

Fig. 1 shows a first embodiment of a separator or baffle device 10 for separating liquid oil from blow-by gas within an engine (not shown) of a vehicle. The baffle device 10 comprises a convoluted passageway defined by a number of baffle passages 30, and an inlet 20 allowing blow-by gas 100 to enter the convoluted passageway.

The changes in velocity and direction of the blow-by gas 100 which occur as the blow-by gas 100 flows through the convoluted passageway tends to separate out the liquid oil 110 contained in the blow-by gas 100. The baffle device 10 includes a drain member 40 having a substantially conical funnel member 44 and a drain outlet 42 for the separated liquid oil 110 which is located at the centre, and at the lowest point, of the funnel member 44. A gas outlet 50 for the cleaned gas 120 is also provided. In this embodiment, the gas outlet 50 extends upwards from an upper portion of the baffle device 10. The baffle device 10, and the drain member 40 in particular, is symmetrical about a vertical axis of the drain outlet 42 (when the vehicle is level). Therefore, the spatial relationship between the baffle passageway and the drain outlet 42 remains substantially the same for practical variations in the orientation of the vehicle.

The baffle device 10 is adapted such that, in use, the drain passage 42 is provided at a horizontally central portion of the engine. It is to be *.S.

understood that this central portion is in relation to a horizontal plane of the engine when the vehicle is level. * *S.

The inlet 20 is provided with means for reducing the velocity of blow-by *S..

gas 100 entering the inlet. This is in the form of an increased diameter of ** ** * * the inlet 20 relative to the diameter of the convoluted passageway. This may ensure that the velocity of blow-by gas 100 entering the inlet 20 is relatively low and so liquid oil collected in the passageway is free to drain back via the inlet 20.

On the other hand, the diameter of the aperture 46 of the drain outlet 42 is designed to be relatively small. In addition, the outlet 42 defines a restricted passage 48 so that liquid 011110 (under no pressure) will tend to be present in the restricted passage 48 and gradually leak from it. The oil provides a barrier to prevent blow-by gas 100 from bypassing the baffle 10 and entering the baffle device 10 via the drain outlet 42 and then enter the induction system.

Figs. 2 and 3 show a second embodiment of the disclosure. Like features are given like reference numerals. This embodiment is similar to the first with three exceptions. Firstly, the gas outlet 50 extends horizontally from an upper portion of the baffle device 10. Secondly, the baffle includes vertical baffle plate portions 32 which are tapered at their free end.

Thirdly, the cylinder head cover provides the upper portion of the baffle device 10.

In each embodiment, the passages, inlets and outlets of the disclosure are often oriented at an oblique angle (when the vehicle is level) and horizontal surfaces in particular are avoided. * SS. * *S..

:. Industrial Applicability * *S. :. 25

In use, blow-by gas 100 enters the baffle device 10 via the inlet 20. Due IS..

to changes in velocity and direction of the blow-by gas 100 within the ** *.

* . baffle passageway, liquid oil 42 is separated from the blow-by gas 100 and cleaned gas exits the baffle device 10 by rising upwards and flowing to the gas outlet 50. A portion of the liquid oil 110 will flow out of the baffle device 10 via the inlet 20. The remainder will flow down the funnel 44 into the drain passage 42 and gather in the restricted passage 48 before leaking from the baffle device 10 via the drain outlet 46.

The present disclosure provides a separator device 10 for removing liquid oil 110 from blow-by gas 100 which has improved drainage since it is locatable at a central region of the engine and so drainage is substantially independent of vehicle orientation. This inhibits damage to the air induction system.

The conical funnel member 44 and central drain passage 42 provide a drain member 40 that is symmetrical. This provides effective draining of the separated oil 110 regardless of the orientation of the vehicle.

The geometry of the baffle passages 30 limits the possibility of sites when liquid oil 110 can gather, in particular by avoiding the use of horizontal surfaces. The sizing of apertures provides suitable velocities of the blow-by gas 100 for efficient separation and drainage.

When the gas outlet 50 extends horizontally from an upper portion of the baffle device 10, this provides a substantial vertical space saving. The inclusion of tapered vertical baffle plate portions 32 eliminates a number of S * horizontal surfaces from which liquid oil may be suspended before being blown through the system by the gases to enter the induction system. *

The cylinder head cover can provide the upper portion of the baffle device and this can also provide a vertical space saving. Generally, the *S *.

: * * integration of parts can provide cost and space savings.

Various modifications and improvements can be made without departing from the scope of the present disclosure. For instance, the present invention does not only apply to engines with closed breather systems. It can be used in open systems in which the blow-by gas is vented to atmosphere. S. * S * *.S * S.. S * * *5. * * * *.. * ***.

S *I.. *S Si * S S

Claims

Claims 1. A baffle device for separating liquid oil from blow-by gas

within an engine, the baffle device comprising: at least one baffle passage having an inlet; a gas outlet; and a drain passage for the separated liquid oil, wherein the baffle device is adapted such that, in use, the drain passage is provided at a substantially central portion of the engine.

2. A baffle device as claimed in Claim 1, wherein the baffle passage is convoluted.

3. A baffle device as claimed in Claim 1 or 2, wherein the drain passage includes a drain member having a substantially conical funnel member, the funnel member including a drain outlet located at the centre, and at the lowest point, of the funnel member.

4. A baffle device as claimed in Claim 3, wherein the drain outlet defines a restricted passage so that liquid oil will tend to be present in the restricted passage and gradually leak from it, thus providing a barrier to prevent blow-by gas from entering the baffle device via the drain outlet. ***.

S *

5. A baffle device as claimed in any preceding claim, wherein the gas * outlet extends upwards from an upper portion of the baffle device. *.S.

6. A baffle device as claimed in any of Claims ito 4, wherein the gas ** I, : * *. outlet extends horizontally from an upper portion of the baffle device.

7. A baffle device as claimed in any preceding claim, wherein the baffle device is symmetrical about a vertical axis of the drain outlet.

8. A baffle device as claimed in any preceding claim, wherein the inlet is provided with means for reducing the velocity of blow-by gas entering the inlet.

9. A baffle device as claimed in Claim 8, wherein the inlet has a greater diameter than the passageway.

10. A baffle device as claimed in any preceding claim, including vertical baffle plate portions which are tapered at their free end.

11. A baffle device as claimed in any preceding claim, wherein one or both of the baffle passage and the inlet are oriented at an oblique angle.

12. A baffle device as claimed in any preceding claim, substantially free of horizontal surfaces.

13. A baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; * * SS a gas outlet; and :. a drain passage for the separated liquid oil, * ** wherein the baffle device is adapted to be, in use, substantially symmetrical about one or more vertical planes of the engine. * ***s ** **

: * ** 14. A baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; and means for reducing the velocity of blow-by gas entering the inlet.

15. A baffle device as claimed in Claim 14, wherein the inlet has a greater diameter than the passageway.

16. A baffle device for separating liquid oil from blow-by gas within an engine, the baffle device comprising: at least one baffle passage having an inlet; a gas outlet; and a drain passage for allowing the separated liquid oil to drain from the baffle device, the drain outlet including: means for preventing blow-by gas from entering the baffle device via the drain passage.

17. A baffle device as claimed in Claim 16, wherein the drain passage defines a restricted passage so that liquid oil will tend to be present in the restricted passage and gradually leak from it, thus providing a barrier to prevent blow-by gas from entering the baffle device via the drain outlet.

18. An internal combustion engine including a baffle device as claimed in any preceding claim.

S

19. An internal combustion engine as claimed in Claim 18, wherein the cylinder head cover provides the upper portion of the baffle device. * *S* :. 25 *I.. S * **S. S. ** * * . * S