GB2361266A

GB2361266A - Automatic system for topping-up the oil in the wet sump of an i.c. engine

Info

Publication number: GB2361266A
Application number: GB0009315A
Authority: GB
Inventors: Michael Neil Basnett
Original assignee: Bayerische Motoren Werke AG; MG Rover Group Ltd
Current assignee: Bayerische Motoren Werke AG; MG Rover Group Ltd
Priority date: 2000-04-14
Filing date: 2000-04-14
Publication date: 2001-10-17
Also published as: GB0009315D0

Abstract

An auxiliary reservoir 13 is arranged above the sump 12 and is connected to it by a feed pipe 14 which includes an electrically operated shut-off valve 21 connected to an engine ignition switch such that the shut-off valve is closed when the ignition is on. During normal running, the level in the sump falls if oil is consumed because the shut-off valve 21 is closed. When the ignition is turned off, the shut-off valve 21 opens to allow oil to flow from the auxiliary reservoir 13 into the sump 12 through the feed pipe 14 and air bubbles to rise through the feed pipe into the auxiliary reservoir 13. When the level in the sump reaches the lower end 15 of the feed pipe 14, air can no longer enter the pipe so that the flow of oil into the sump ceases. In a modification, the feed pipe (114, fig.2) terminates below the desired oil level and a return air vent pipe (131) terminates at that level. When the filler cap 25 is removed to replenish the auxiliary reservoir 13, a microswitch 26 closes shut-off valve 21 to prevent the sump being flooded. Alternatively, a spring-loaded valve member (235, fig.3) blocks the feed outlet pipe (217) when the filler cap (225) is removed.

Description

2361266 Enizine Oil Supply The invention relates to an oil supply

arrangement for an internal combustion engine. Such engines usually include an oil sump which, in a piston engine, is normally formed as a lower portion of a crank case. Usually such a sump acts as an oil reservoir and is termed a "weC sump but in some installations oil may be scavenged from the sump into a separate reservoir, such a sump being termed a "dry" sump. The quantity of oil retained in the reservoir is usually determined by testing its level with a dipstick. However, it may be difficult in certain engine installations to provide ready access for the dipstick and this in itself becomes a deterrent to regular checking of the oil level.

There have been proposals for providing automatic systems which top-up the oil in a wet sump from an auxiliary reservoir but.these have tended to be either over simplified and require regular manual attention or are relatively complicated and potentially expensive. The present invention has as an object the provision of an oil supply arrangement using an auxiliary reservoir which avoids these shortcomings.

According to the invention there is provided an oil supply arrangement for an internal combustion engine, the arrangement comprising an oil reservoir which in use contains oil up to a datum level and from which the oil is in use drawn by the engine for lubrication thereof, an auxiliary reservoir arranged above the datum oil level and which is usually closed to atmosphere, passage means connecting the oil reservoir and the auxiliary reservoir, the passage means including a pipe having an open lower end at the datum level such that when the level of oil in the oil reservoir is below said lower end oil can flow from the auxiliary reservoir into the sump and when the level of oil in the oil reservoir is above said lower end such flow is inhibited by a reduced pres sure in the auxiliary reservoir, the passage means includes valve means operatively connected to the engine to prevent the flow of oil from the auxiliary reservoir into the oil reservoir when the engine is running.

Conveniently, the valve means is electrically operated, for example by being connected to an ignition switch for the engine. Alternatively, the valve means may be operated by fluid pressure, e.g. by inlet manifold depression or by engine oil pressure.

The passage means may comprise a feed pipe having an upper opening in the auxiliary reservoir adjacent a lower end thereof. It may further comprise a vent pipe having a lower end constituting said lower end of the passage means and an upper end opening in the auxiliary reservoir or into the feed pipe adjacent the auxiliary reservoir.

Conveniently, the auxiliary reservoir has a filler orifice which is normally closed by closure means which is operatively connected to said valve means such that said valve means closes the passage means when the closure means is released to open the filler orifice. Where the valve means is electrically operated, the.closure means may include switch means arranged to operate the valve me s when the closure means exposes the orifice. Alternatively, the valve means includes an auxiliary valve which is operatively connected to the closure means to prevent the flow of oil from the auxiliary reservoir into the oil reservoir except when the closure means is in place to close the orifice. The auxiliary valve may comprise a spring loaded valve member which is unseated by the closure means when the closure means is in place to close the orifice. A pushrod may extends through the orifice and be linked to the valve member, the closure means comprising a cap which presses in the pushrod to move the valve member when the cap is in place over the orifice.

The invention will now be described by way of example and with reference to the accompanying drawings of which:

Fig.1 is a diagrammatic cross-section of an oil supply arrangement for an internal combustion engine according to the invention; Fig.2 is a view similar to Fig. 1 showing a modification; and Fig. 3 is a cross-section showing an alternative to an auxiliary reservoir shown in Fig. 1.

Referring to Fig. 1, an internal combustion engine 11 has a sump 12 which acts as an oil reservoir for lubricating oil - i.e. a wet sump. An auxiliary reservoir 13 is arranged above the sump 12 or, more particularly, above a datum oil level H.

The auxiliary reservoir 13 is connected to the sump 12 by passage means in the form of a feed pipe 14 which comprises an engine mounted pipe 18 having an open lower end 15 at the datum level H, a flexible pipe 16 and a stub pipe 17 on the auxiliary reservoir which opens into the auxiliary reservoir adjacent its lower end.

Valve means in the form of an electrically operated shut-off valve 21 is included in the feed pi e 14. This is shown for convemencp in the flexible pipe 16 IP but may be situated anywhere along the feed pipe 14. The shut-off valve 21 is connected to an ignition switch for the engine 11 as indicated diagrammatically by the positive (+) supply lead 22 such that when the ignition is on, i.e., when the engine is running, the shut-off valve 21 is closed.

The auxiliary reservoir 13 includes a filler orifice 24 which is normally closed by closure means in the form of a filler cap 25. The filler cap 25 is mechanically connected to a microswitch 26 which is electrically connected to a permanent electrical source as indicated diagrammatically at 27 and is arranged so that the microswitch 26 connects the shut-off valve 21 to the permanent electricity supply 27 if the filler cap 25 is removed.

"4- In use, the sump 12 is filled to the datum level H and the auxiliary reservoir 13 is filled to a level approaching its maximum capacity. During normal engine running the shut-off valve 21 is closed. If oil is consumed by the engine then the level in the sump 12 can fall as indicated by the lower level L. When the engine is stopped and the ignition is turned off, then the shut-off valve 21 opens and oil can flow from the auxihary reservoir 13 through the feed pipe 14 to raise the level of oil in the sump 12. Although the auxiliary reservoir 13 is closed to atmosphere by virtue of the filler cap 25 closing the filler orifice 24, air can enter as air bubbles rising from the pipe lower end 15. When the level in the sump 12 has risen to that of the pipe lower end 15, this air can no longer enter the feed pipe 14 so that oil flow is inhibited by a reduced pressure in the auxiliary reservoir 13 induced by the weight of oil and the flow of oil from the auxiliary reservoir into the sump ceases.

When it becomes necessary to replenish the auxiliary reservoir 13 with oil the filler cap 25 is removed thereby causing the shut-off valve 21 to close by virtue of the electrical supply through the micro switch 26. This prevents oil flooding into the engine when the reduced pressure is broken.

In the modification shown in Fig.2, parts which are the same as or similar to those in Fig. 1 carry the same reference numeral with the addition of 100. In this modification the feed pipe 114 terminates below the datum oil level H and a vent pipe 131 which has a lower end 115 at the datum level in the sump 112 is connected to the auxiliary reservoir 113 separately from the main feed pipe 114.

The vent pipe 131 enters the auxiliary reservoir 113 above the normal oil level and provides a separate passage for air to escape without the need for air bubbles to rise through the feed pipe 114. However, the vent pipe 131 could conveniently be connected to the auxiliary reservoir 113 at a lower level or could extend through the feed pipe 114 in the manner shown in GB 1352 457. In such a case, and as described in GB 1352 457, the vent pipe could terminate in the feed pipe itself adjacent the auxiliary reservoir.

In Fig.3 parts which are the same as or similar to those shown in Fig. 1 carry the same reference numeral but the addition of 200. In this arrangement of an alternative auxiliary reservoir 213, an auxiliary valve which includes a spring-loaded valve member 235 is provided to block the feed stub pipe 217 when the filler cap 225 is removed from the orifice 224. A pushrod 236 extends through the orifice 224, being guided by a spoked insert 237 in the filler orifice 224 and connected to the valve member 235 by a rocker lever 238. In a modification (not shown), the spring-loaded valve member 235 is inverted and the pushrod 236 is arranged to act directly on it.

When the filler cap 225 is in place it acts on the pushrod 236 to hold the valve member 235 off its seat so that the sump can be filled when the engine is stopped as previously described. If the filler cap 225 is removed, the pushrod 236 can rise so that the valve member 235 seats and oil cannot flow into the sump. In a modification, not shown, the pushrod is fast with the filler cap and acts as a dipstick to cheek the level of oil in the auxiliary reservoir.

It will be understood that by referring to the ignition switch of the engine that this term is also conveniently and frequently used to describe the starter/running switch for a diesel engine. Whilst such a switch is not linked to an ignition circuit as such, it enables any electronic injection controls and is connected into any electro-mechanical stop actuator. As an alternative to the electrically operated' valve 21, 121, there may be a fluid pressure operated valve which could be operated by the inlet manifold depression or by engine oil pressure so as to be closed when the engine is running.

-6 It will be appreciated that the arrangement described provides a simple and reliable system for topping-up a normal oil sump without the requirement for additional pumps or sensors in the engine itself. By preventing flow in the feed pipe 14, 114 when the engine 11, 111 is running, there is a reduced tendency for the oil level to rise due to transient conditions caused by the engine, e.g. crankcase pressure fluctuations or vibrations. Also, when installed in a vehicle, fluctuations due to braking and cornering are prevented. The pipe lower end 15, 115 is preferably in the centre of the sump to minimise level fluctuations caused by parking on a slope.

Whilst the arrangement has been described in relation to a wet sump engine, it could equally be applied to the main oil reservoir of a dry sump lubrication system.

Claims

1. An oil supply arrangement for an internal combustion engine, the arrangement comprising an oil reservoir which in use contains oil up to a datum level and from which the oil is in use drawn by the engine for lubrication thereof, an auxiliary reservoir arranged above the datum oil level and which is usually closed to atmosphere, passage means connecting the oil reservoir and the auxiliary reservoir, the passage means including a pipe having an open lower end at the datum level such that when the level of oil in the oil reservoir is below said lower end oil can flow from the auxiliary reservoir into the sump and when the level of oil in the oil reservoir is above said lower end such flow is inhibited by a reduced pressure in the auxiliary reservoir, the passage means includes valve means operatively connected to the engine to prevent the flow of oil from the auxiliary reservoir into the oil reservoir when the engine is running.

2. An arrangement according to claim 1 wherein the valve means is electrically operated.

3. An arrangement according to claim 2 wherein the valve means is connected to an ignition switch for the engine.

An arrangement according to claim 1 wherein the valve means is operated by fluid pressure.

5. An arrangement according to claim 4 wherein the valve means is operated by inlet manifold depression.

6. An arrangement according to claim 4 wherein he valve means is operated by engine oil pressure.

An arrangement according to any preceding claim wherein the passage means comprises a feed pipe having an upper opening in the auxiliary reservoir adjacent a lower end thereof.

8. An arrangement according to claim 7 wherein the passage means comprises a vent pipe having a lower end constituting said lower end of the passage means and an upper end opening in the auxiliary reservoir or into the feed pipe adjacent the auxiliary reservoir.

An arrangement according to any preceding claim wherein the auxiliary reservoir has a filler orifice which is normally closed by closure means which is operatively connected to said valve means such that said valve means closes the passage means when the closure means is released to open the filler orifice.

10. An arrangement according to claim 9 when dependent upon claim 2 wherein the closure means includes switch means arranged to operate the valve means when the closure means exposes the orifice.

11.. An arrangement according to claim 9 wherein the valve means includes an auxiliary valve which is operatively connected to the closure means to prevent the flow of oil from the auxiliary reservoir into the oil reservoir except when the closure means is in place to close the orifice.

12. An arrangement according to claim 11 wherein the auxiliary valve comprises a spring loaded valve member which is unseated by the closure means when the closure means is in place to close the orifice.

13. An arrangement according to claim 12 wherein a pushrod extends through the orifice and is linked to the valve member, the closure means comprising a cap which presses in the pushrod to move the valve member when the cap is in place over the orifice.

14. An oil supply arrangement for an internal combustion engine substantially as described herein with reference to Fig.1, Fig.2 or Fig.1 as modified with reference to Fig.3 of the accompanying drawings.