DE102010009256A1 - Lubricating system for an internal combustion engine - Google Patents

Abstract

Lubricating system (1) for an internal combustion engine with a pressure circulation lubrication for supplying at least one bearing point (2) with a lubricant, wherein the lubricant in a lubricant pan (3) can be collected, from which the lubricant is pumped with a lubricant pump for the pressure circulation lubrication and the internal combustion engine has a start-stop function and wherein a second, electrically operable lubricant pump (4) is provided with the lubricant at least at a standstill of the internal combustion engine to the at least one bearing point (2) can be brought.
The inventive design of the internal combustion engine leads to a reduction of wear in the engine mounts by the start-stop function, whereby the life of the internal combustion engine is extended.

Description

The invention relates to a lubrication system for an internal combustion engine with the features of the preamble of patent claim 1.

The invention is based, for example, on the current BMW 1 Series or 3 Series, in which the internal combustion engines have a lubrication system with a pressure circulation lubrication for supplying the bearing points with a lubricant. Here, the lubricant in the lubricant pan can be collected and pumped with a lubricant pump for pressure circulation lubrication. In addition, these vehicles have internal combustion engines with a so-called. Start-stop function for idling. As part of the efficient dynamics strategy, the BMW Group has introduced the Auto Start-Stop function for all models of the BMW 1 Series and 3 Series with 4-cylinder internal combustion engine and manual transmission, as well as for the Mini vehicles. If this function is active, the internal combustion engine is automatically switched off when the vehicle stops at an intersection or in an idle traffic jam and is restarted within fractions of a second when the vehicle is engaged. Thus, idling phases of the internal combustion engine can be almost completely avoided, which leads, especially in city traffic to significant consumption reductions.

Internal combustion engines with start-stop function or hybrid drives are characterized in that the engine is often turned off and then restarted when needed. The engine start should then take place as quickly as possible, on the one hand to ensure reasonable comfort and on the other hand, a fast availability of the drive.

Is the internal combustion engine, so is also in the usual way of the internal combustion engine driven lubricant pump for the pressure circulation lubrication. The lubricant pressure builds up over the bearing points by draining lubricant. The internal combustion engine internal pressurized lubricant pressure chamber runs slowly empty. With a fast engine start now driven by the engine, mechanical lubricant pump must first pump as much lubricant in the lubricant pressure chamber until it is completely filled again and only then can build up a lubricant pressure. It is usually too low or no lubricant pressure available at a fast engine start. This can lead to wear due to insufficient lubrication conditions in the engine mounts (eg, crankshaft bearings, connecting rod bearings, camshaft bearings, etc.). This wear can be so great as to shorten the engine life, and because of increased clearance in the bearings, the engine acoustics are degraded or other effects occur. To some extent, very high quality and expensive materials are used today to reduce such effects (eg very high-quality wear-resistant bearing materials). Or very expensive and expensive additional measures have to be taken in order to ensure lubricant supply even when starting the internal combustion engine quickly (eg lubricant pressure accumulator, etc.).

Object of the present invention is to provide a simple and inexpensive measure to o. G. To avoid disadvantages.

This object is achieved by the feature in the characterizing part of patent claim 1. The invention thus represents a simple and very cost-effective solution to the problem described in the form that the expiring during an engine stall via the bearings from the lubricant pressure chamber lubricant amount is nachgefördert during the engine stall. Unlike other elaborate solutions here is deliberately not attempted to maintain the lubricant pressure by additional measures, but it is nachgefördert only the expired from the bearings lubricant quantity. Thus, the lubricant pressure chamber is always completely filled. The main bearings are thus always filled in a simple manner with lubricant. When restarting the engine significantly less or no deficiency lubrication effects and associated wear occur and the lubricant pressure can be established immediately by the standard lubricant pump for pressure circulation lubrication.

The embodiment according to claim 2 is a second particularly preferred embodiment. In this case, the lubricant is not applied directly to a bearing, but a reservoir filled, from which purely by gravity, the lubricant during the stoppage of the internal combustion engine to the bearing, for example by dripping, can be brought. The reservoir must be located above the bearing points to be lubricated, this can, for. B. in the cylinder head.

As already described above, the second lubricant pump according to claim 3 requires a significantly lower flow rate than the lubricant pump for pressure circulation lubrication. Thus, it can be kept structurally very small in an advantageous manner with an extremely low energy consumption and very low production costs.

According to claim 4, in a further, particularly preferred embodiment, the lubricant from the reservoir through at least one line can be moved directly to the long position. This ensures that also z. B. at a tilt of the vehicle in the state, the lubricant always lands on the bearing.

Particularly preferably, further, the reservoir according to claim 5 in the regular engine operation of the lubricant pressure chamber z. B. be separated by a check valve or a switching valve.

In the following, the invention is explained in more detail with reference to two particularly preferred embodiments in two figures.

1 schematically shows a first embodiment of an inventive lubricating system for an internal combustion engine.

2 schematically shows a second embodiment of an inventive lubricating system for an internal combustion engine.

Below, the same reference numerals apply to like components in both figures.

1 schematically shows a first embodiment of a lubricating system according to the invention 1 for an internal combustion engine. A pressure circulation lubrication usually present in the internal combustion engine for supplying at least one bearing point 2 with a lubricant is not explicitly shown. Representative of this are four storage locations 2 represented, each symbolically represent a lubricant gap, which is lubricating means in communication with the pressure circulation lubrication. This may be, for example, four main crankshaft bearings or camshaft bearing. The lubricant for the pressure circulation lubrication is in a lubricant trough 3 collectible, a lubricant level is dash-dotted with 8th quantified. The internal combustion engine itself is equipped with a so-called start-stop system. Under a start-stop system not only the case mentioned above is understood, but also a hybrid vehicle operation, which has the same problems. To overcome these problems, according to the invention is a second, electrically operable lubricant pump 4 provided with the at least at a standstill of the internal combustion engine lubricant to the at least one bearing point 2 can be brought. On the pressure side of the second lubricant pump 4 is a check valve 6 provided, which may be omitted in other embodiments, however, or by a switching valve 7 , as in 2 represented, can be replaced. As a piping of such a lubrication system 1 the skilled person is generally known, this is not explicitly described.

Operating principle of the first embodiment of the lubrication system 1 : The lubricant that runs out of the lubricant pressure chamber when the engine stops, is supplied via a very small, electric refill lubricant pump, the second lubricant pump 4 , post-funded. In this case, the solution differs from others in that the small inexpensive and low power connected lubricant pump 4 It is not the task to build up or increase lubricant pressure. It's just there for the low, the over the bearings 2 nachzufördern lubricant in the lubricant pressure chamber running off. The lubricant pump 4 usually only runs when the engine stops during an expected restart. Of course, it could also be switched on in normal engine operation, for example, as an emergency function, if the pressure circulation lubrication should fail or lose capacity. The supply of lubricant to the bearing 2 via the lubricant pump 4 can via a check valve 6 or via a switching valve 7 be decoupled from the lubricant pressure chamber.

2 schematically shows a second embodiment of a lubricating system according to the invention 1 for an internal combustion engine. The second embodiment in 2 differs from the first embodiment in 1 in that on the pressure side of the second lubricant pump 4 the bearings 2 a reservoir 5 upstream. From this reservoir can now drop at standstill of the engine lubricant on the bearings, for example. In a further embodiment, it is also possible, the lubricant via lines directly, as shown here, to the bearings 2 to always have a targeted lubrication. According to the first embodiment, between the lubricant reservoir 5 and the depository 2 again a check valve 6 or a switching valve 7 be provided.

Operating principle of the second embodiment of the lubrication system 1 :

The reservoir 5 is one above the lubricant pressure chamber or bearings 2 arranged storage tank, via a switching valve or a check valve 7 From the lubricant pressure chamber is separable. During internal combustion engine operation and existing lubricant pressure, the switching valve 7 opened and the store filled. So that the existing air can escape from the memory and the reservoir 5 can fill, a small, not shown vent hole is provided. When switching off the internal combustion engine, the switching valve 7 open, leaving over the depository 2 From the lubricant pressure chamber effluent lubricant from the reservoir 5 can run after. The venting of the reservoir now takes place again via the small venting bore 5 so that the lubricant can drain out of it. When restarting the internal combustion engine, the switching valve 7 closed, so that lubricant pressure builds up quickly in the lubricant pressure chamber. Only when sufficient lubricant pressure is present, the switching valve 7 be reopened to refill the reservoir. The engine stops taking so long that the reservoir 5 This is done with the help of the second lubricant pump 4 filled again.

Of course, the reservoir 5 be designed to be open at the top, so that, for example, during the running of the internal combustion engine of cam of a camshaft spilled lubricant with the reservoir 5 is collected, which then drips back to the bearings at standstill of the engine.

• • Durch die erfindungsgemäße Ausgestaltung des Schmiersystems für eine Brennkraftmaschine wird der Verschleiß in den Brennkraftmaschinenlagerungen durch Start-Stopp bzw. Hybridbetrieb vermieden und die Lebensdauer der Brennkraftmaschine verlängert.
• • Weiter handelt es sich um eine äußerst kostengünstige Lösung mit geringem Bauraumbedarf.
• • Es ist nur eine einfache Ansteuerung oder im einfachsten Fall keine Ansteuerung erforderlich.
• • Weiter vorteilhaft ist der extrem geringe Energieverbrauch bzw. kein Energieverbrauch.
• • Ein weiterer Vorteil liegt in dem sehr geringen Gewicht des Gesamtsystems.
• • Darüber hinaus findet nur eine sehr geringe Mehrung des Schmiermittelfüllvolumens statt.
• • Insgesamt führt die Erfindung zu einer Verringerung des Risikos einer Verschlechterung der Brennkraftmaschinenakustik aufgrund sich vergrößernder Lagerspiele über die Laufzeit.
• • In vorteilhafter Weise besteht weiterhin die Möglichkeit kostengünstigere Lagerwerkstoffe einzusetzen.

The bearings 2 may be, for example, valve train bearing points, such as camshaft bearings or crankshaft bearings.

• • The inventive design of the lubricating system for an internal combustion engine, the wear in the engine mounts by start-stop or hybrid operation is avoided and extends the life of the engine.
• • Furthermore, it is a very cost-effective solution with a small space requirement.
• • It is only a simple control or in the simplest case, no control required.
• • Another advantage is the extremely low energy consumption or energy consumption.
• • Another advantage is the very low weight of the overall system.
• • In addition, there is only a very small increase in the lubricant filling volume.
• Overall, the invention leads to a reduction of the risk of deterioration of the engine acoustics due to increasing bearing play over the term.
• Advantageously, it is still possible to use cheaper bearing materials.

LIST OF REFERENCE NUMBERS

1

lubrication system

2

depository

3

lubricant sump

4

lubricant pump

5

reservoir

6

check valve

7

switching valve

8th

lubricant levels

Claims (5)

Lubrication system ( 1 ) for an internal combustion engine with a pressure circulation lubrication for supplying at least one bearing point ( 2 ) with a lubricant, wherein the lubricant in a lubricant pan ( 3 ) is collectible, from which the lubricant with a lubricant pump for pressure circulation lubrication is pumped and wherein the internal combustion engine has a start-stop function, characterized in that a second, electrically operable lubricant pump ( 4 ) is provided with the at least at a standstill of the internal combustion engine lubricant to the at least one bearing point ( 2 ) can be brought. Lubricating system according to claim 1, characterized in that the lubricant with the second lubricant pump ( 4 ) into a reservoir ( 5 ) is pumpable, which is geodetically higher than the at least one storage location ( 2 ) and wherein during the stoppage of the engine lubricant from the reservoir ( 5 ) to the at least one depository ( 2 ) can be brought. Lubricating system according to claim 1 or 2, characterized in that the second lubricant pump ( 4 ) has a lower flow rate than the lubricant pump. Lubricating system according to one of the claims 1 to 3, characterized in that the lubricant from the reservoir ( 5 ) through a line to the at least one storage location ( 2 ) can be brought. Device according to claim 4, characterized in that in the line a check valve ( 6 ) and / or a switching valve ( 7 ) is provided.

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