Methods for evaluating the lubrication of an apparatus which can be lubricated by means of a lubricant circuit

Abstract

A method for evaluating the lubrication of friction components of an apparatus which can be lubricated by means of a lubricant circuit. A lubricant pump of the lubricant circuit is drivable by a drive engine. A pressure ascertainment unit continuously ascertains the lubricant pressure at at least one defined region of the lubricant circuit during an engine start procedure. A travel ascertainment unit is provided, by means of which at multiple pressure points in time, at each of which the lubricant pressure ascertained exceeds a defined pressure limiting value (p.sub.1, p.sub.2, p.sub.3), the relative travel between the friction components since the beginning of the engine start procedure is ascertained or estimated, and an analysis unit, by means of which an evaluation value, is ascertained from the total of the relative travel values (.sub.1, .sub.2, .sub.3) ascertained at the pressure points in time.

Claims

1. A method for evaluating the lubrication of friction components, which rub against one another, of an apparatus which can be lubricated by means of a lubricant circuit, wherein a lubricant pump of the lubricant circuit is drivable by means of a drive engine forming the apparatus or by means of a drive engine driving the apparatus, comprising: providing a pressure ascertainment unit, by means of which the lubricant pressure at at least one defined region of the lubricant circuit is continuously ascertained during an engine start procedure, providing a travel ascertainment unit, by means of which at multiple pressure points in time, at each of which the lubricant pressure ascertained by means of the pressure ascertainment unit exceeds a defined pressure limiting value (p.sub.1, p.sub.2, p.sub.3), the relative travel between the friction components since the beginning of the engine start procedure is ascertained or estimated, and providing an analysis unit, by means of which an evaluation value, which evaluates the lubricant pressure buildup during the engine start procedure, is ascertained from a total of relative travel values (.sub.1, .sub.2, .sub.3) ascertained at the pressure points in time.

2. The method according to claim 1, wherein the ascertained pressure values or the ascertained relative travel values (.sub.1, .sub.2, .sub.3) are each weighted before the summation thereof by means of a weighting factor, wherein by means of these weighting factors, the different damage potentials at the multiple travel points in time or the multiple pressure points in time for damage of the apparatus due to excessively slow lubricant pressure buildup are taken into consideration.

3. The method according to claim 1, wherein the evaluation values ascertained for multiple engine starts are statistically analysed by means of the analysis unit, wherein the frequency distribution of the evaluation values ascertained for multiple engine starts is ascertained, in the form of a histogram, by means of the analysis unit.

4. The method according to claim 1, wherein the analysis unit has a signalling connection to a warning unit, by means of which a warning signal is independently output to a person operating the apparatus as a function of at least one evaluation value ascertained by means of the analysis unit.

5. The method according to claim 1, wherein the pressure ascertainment unit is formed by at least one pressure sensor for measuring the lubricant pressure.

6. The method according to claim 1, wherein a further evaluation value, which evaluates a lubricant pressure decrease during an engine shutdown procedure, is ascertained by means of the analysis unit from the total of relative travel values ascertained during an engine shutdown procedure or from the total of pressure values ascertained during an engine shutdown procedure.

7. The method according to claim 1, wherein the pressure ascertainment unit, viewed in a lubricant flow direction, is arranged downstream of the lubricant pump and upstream of a friction component region to be lubricated.

8. The method according to claim 1, wherein the lubricant pump is connected in a torque-transmitting manner to a crankshaft of an internal combustion engine as the drive engine, so that the at least one lubricant pump is rotationally drivable by means of the internal combustion engine.

9. The method according to claim 8, wherein the travel ascertainment unit is formed by a crank angle ascertainment unit, by means of which the crank angle covered by the crankshaft since the beginning of the engine start procedure is ascertained to estimate the relative travel between the friction components.

10. The method according to claim 1, wherein for the evaluation of the lubricant pressure buildup by means of the analysis unit as a function of the ascertained total, an evaluation value is selected from a defined number of predefined evaluation values forming different evaluation levels.

11. The method according to claim 10, wherein the predefined evaluation values is in a range of 3 to 6 evaluation values.

12. The method according to claim 1, wherein the number of the pressure points in time is in a range of 2 to 10.

13. The method according to claim 12, wherein the number of the pressure points in time is in a range of 3 to 5.

14. The method according to claim 1, wherein the ascertained evaluation value is stored in a storage unit of the analysis unit either permanently or so the value is readable by means of a readout device.

15. The method according to claim 14, wherein the ascertained evaluation value is stored in the storage unit for a defined period of time, or a defined number of engine starts, or only a part of the evaluation values ascertained for multiple engine starts is permanently stored in the storage unit.

16. A method for evaluating the lubrication of friction components, which rub against one another, of an apparatus which can be lubricated by means of a lubricant circuit, wherein a lubricant pump of the lubricant circuit is drivable by means of a drive engine forming the apparatus or by means of a drive engine driving the apparatus, comprising: providing a travel ascertainment unit, by means of which the relative travel between the friction components since the beginning of the engine start procedure is continuously ascertained and/or estimated during an engine start procedure, providing a pressure ascertainment unit, by means of which, at multiple travel points in time, at each of which the relative travel ascertained by means of the travel ascertainment unit between the friction partners exceeds a defined relative travel limiting value, the lubricant pressure is ascertained at at least one defined region of the lubricant circuit, and providing an analysis unit, by means of which an evaluation value, which evaluates the lubricant pressure buildup during the engine start procedure, is ascertained from the total of the pressure values ascertained at the travel points in time.

17. The method according to claim 16, wherein the lubricant pump is connected in a torque-transmitting manner to a crankshaft of an internal combustion engine as the drive engine, so that the at least one lubricant pump is rotationally drivable by means of the internal combustion engine.

18. The method according to claim 16, wherein the number of the travel points in time is in a range of 2 to 10.

19. The method according to claim 18, wherein the number of the travel points in time is in a range of 3 to 5.

20. A device comprising: a lubricant circuit, having a lubricant pump, for lubricating an apparatus, wherein the lubricant pump is drivable by means of a drive engine forming the apparatus or by means of a drive engine driving the apparatus, a pressure ascertainment unit, by means of which the lubricant pressure can be ascertained at at least one defined region of the lubricant circuit during an engine start procedure, a travel ascertainment unit, by means of which the relative travel between friction components, which are to be lubricated and rub against one another, of the apparatus since the beginning of the engine start procedure can be ascertained and/or estimated during the engine start procedure, and; an analysis unit, by means of which an evaluation value, which evaluates the lubricant pressure buildup during the engine start procedure, can be ascertained from relative travel values (.sub.1, .sub.2, .sub.3) ascertained during the engine start procedure or from pressure values ascertained during the engine start procedure.

21. The device of claim 20, wherein the device is incorporated into a vehicle.

22. The device of claim 21, wherein the vehicle is a utility vehicle.

23. The method according to claim 4, wherein the warning signal is an optical or acoustic warning signal.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a schematic illustration of the construction of a device according to the present disclosure;

(2) FIG. 2 shows a diagram, on the basis of which a method according to the present disclosure is explained;

(3) FIG. 3 shows a flow chart, on the basis of which the method is explained; and

(4) FIG. 4 shows a second embodiment of a method according to the present disclosure in an illustration according to FIG. 3.

DETAILED DESCRIPTION

(5) FIG. 1 schematically shows the construction of a device 1 according to the present disclosure. The device 1 has here, for example, an internal combustion engine 3, which is indicated by dashed lines, comprising a lubricant circuit 5. Friction components of the internal combustion engine 3 which rub against one another are lubricated by means of the lubricant circuit 5, so that the wear of these friction components is reduced. By means of the lubricant circuit 5, for example, the camshafts, the crankshaft bearings, the big end bearings, the small end bearings, tappets, and rocker arms of the internal combustion engine are lubricated and/or supplied with lubricant, for example, with lubricant oil here, as friction components.

(6) The internal combustion engine 3 can be associated, for example, with a vehicle (not shown in the figures), so that the internal combustion engine forms a drive engine for driving the vehicle. Alternatively, the internal combustion engine 3 could also, however, be formed by a fixed or stationary internal combustion engine.

(7) As is furthermore shown in FIG. 1, the lubricant circuit 5 has here, viewed in the lubricant flow direction, an oil pan 7, a lubricant pump 9, an oil filter 11, a pressure sensor 13 for measuring the oil pressure, and a lubricating section 15, which is indicated by dashed lines. By means of the lubricant pump 9, the lubricant oil collected in the oil pan 7 is suctioned out of the oil pan 7 and conveyed via the further lubricant circuit. The lubricant pump 9 is connected for this purpose here in a torque-transmitting manner to a crankshaft (not shown in the figures) of the internal combustion engine 3, so that the lubricant pump 9 can be rotationally driven by means of the internal combustion engine 3. The components to be lubricated of the internal combustion engine 3 are supplied with lubricant in the lubricating section 15 of the lubricant circuit 5.

(8) As is furthermore apparent from FIG. 1, the pressure sensor 13 of the internal combustion engine 3 has a signalling connection to an analysis unit 17 of the device 1. The analysis unit 17 can be formed, for example, by a central control unit for controlling the internal combustion engine 3 and further components. Moreover, the analysis unit 17 also has a signalling connection here to a crank angle sensor 19 of the internal combustion engine 3, by means of which the present crank angle of the internal combustion engine crankshaft can be measured. By means of the measurement data of the pressure sensor 13 and the crank angle sensor 19 transmitted to the analysis unit 17, the analysis unit 17 can ascertain evaluation values, by means of which the lubricant pressure buildup during an engine start procedure and also the lubricant pressure decrease during an engine shutdown procedure can be informatively evaluated.

(9) FIG. 2 shows a diagram in which two curves 21, 22 are plotted, which are to illustrate a good and a bad lubricant pressure buildup during an engine start procedure. The curves 21, 22 each show in this case the lubricant pressure p during an engine start procedure as a function of the crank angle covered since beginning the engine start procedure. The curve 21 shows the good lubricant pressure buildup, in which the lubricant pressure p rises significantly more rapidly than in the curve 22, which shows the bad lubricant pressure buildup. Moreover, the pressure value p.sub.B is also plotted in the diagram, which is to represent the minimal operating pressure of the lubricant circuit 5. This pressure can be 4 bar in an internal combustion engine, for example.

(10) The ascertainment of an evaluation value for the evaluation of the lubricant pressure buildup during an engine start procedure will be explained in greater detail hereafter on the basis of FIG. 3.

(11) At the beginning of an engine start procedure, which can be acquired, for example, by turning on the ignition of a vehicle having the internal combustion engine, the pressure sensor 13 and the crank angle sensor 19 are activated, so that the present oil pressure and the present crank angle of the internal combustion engine crankshaft are continuously transmitted to the analysis unit 17. The analysis unit 17 then ascertains the crank angle covered by the internal combustion engine crankshaft since the beginning of the engine start procedure via the measurement data of the crank angle sensor 19. In this manner, by means of the analysis unit 17, the relative travel between a plurality of friction components, which rub against one another, of the internal combustion engine 3 since the beginning of the engine start procedure can be estimated with high accuracy.

(12) Subsequently, initially a first travel point in time is ascertained by means of the analysis unit 17 in a step 23 from the measurement data of the crank angle sensor 19, at which the crank angle covered since the beginning of the engine start procedure exceeds a first defined crank angle limiting value .sub.1 (FIG. 2). In a following step 25, the oil pressure at the first travel point in time is then ascertained by means of the analysis unit 17 from the measurement data of the pressure sensor 13. Subsequently, steps 23, 25 are repeated until all travel points in time and the associated oil pressure values are ascertained. Overall, for example, three travel points in time are ascertained here, at each of which the crank angle covered since the beginning of the engine start procedure exceeds a defined crank angle limiting value .sub.1, .sub.2, .sub.3 (FIG. 2). In the case of a lubricant pressure buildup according to curve 21 of FIG. 2, the pressure values p.sub.21, p.sub.22, p.sub.23 corresponding to the three crank angle limiting values .sub.1, .sub.2, .sub.3 are then accordingly ascertained here. In the case of a lubricant pressure buildup according to curve 22 of FIG. 2, the pressure values p.sub.11, p.sub.12, p.sub.13 are ascertained.

(13) According to FIG. 3, in a step 27, the evaluation value for evaluating the lubricant pressure buildup during the engine start procedure is then ascertained from the total of the ascertained pressure values. Specifically, the ascertained pressure values are each weighted by means of a weighting factor before the summation thereof here for this purpose. By means of these weighting factors, the different damage potentials at the multiple travel points in time for damage to the internal combustion engine 3 due to excessively slow lubricant pressure buildup are taken into consideration. An evaluation value is then selected by means of the analysis unit 17 from a defined number of predefined evaluation values forming different evaluation levels as a function of the total of the weighted pressure values. In this manner, the quality of the lubricant pressure buildup during the engine start procedure is classified. It is preferably provided in this case that the number of the evaluation levels is in a range of 3 to 6. A higher total value of the weighted pressure values then results here in a more positive evaluation of the lubricant pressure buildup than a lower total value.

(14) Subsequently, in a step 29, the ascertained evaluation value is stored in a storage unit 31 of the analysis unit 17. The evaluation value is stored here such that it can be read out by means of a suitable readout device at a later point in time. In a step 33, it is then moreover checked by means of the analysis unit 17 on the basis of the ascertained evaluation value whether the pressure buildup during the engine start procedure is inadequate or impermissible. If this is the case, a warning unit 35 (FIG. 1) having a signal connection to the analysis unit 17 is independently or automatically activated by means of the analysis unit 17. A warning signal is then output to an operator of the internal combustion engine 3 by means of the warning unit 35. The warning unit 35 can be formed in this case, for example, by a warning light or a loudspeaker.

(15) The ascertainment of an evaluation value for evaluating the lubricant pressure decrease during an engine shutdown procedure takes place in an identical manner, wherein the evaluation value is then ascertained here from the total of crank angle values ascertained during the engine shutdown procedure by means of the analysis unit 17.

(16) FIG. 4 shows a flow chart, on the basis of which a second embodiment of a method according to the present disclosure will be explained hereafter.

(17) In comparison to the method shown in FIG. 3, after the beginning of the engine start procedure, in steps 37, 39, multiple pressure points in time are ascertained here by means of the analysis unit 17 from the measurement data of the pressure sensor 13, at each of which the lubricant pressure measured by means of the pressure sensor 13 exceeds a predefined defined pressure limiting value. Moreover, the crank angle covered since the beginning of the engine start procedure at the respective pressure point in time is ascertained here by means of the analysis unit 17 from the measurement data of the crank angle sensor 19. Subsequently, in a step 41, the evaluation value for evaluating the lubricant pressure buildup during the engine start procedure is ascertained from the total of the ascertained crank angle values. A lower total value of the crank angle values results here in a more positive evaluation of the lubricant pressure buildup than a higher total value.

LIST OF REFERENCE NUMERALS

(18) 1 device 3 internal combustion engine 5 lubricant circuit 7 oil pan 9 lubricant pump 11 oil filter 13 pressure sensor 15 lubricating section 17 analysis unit 19 crank angle sensor 21 curve 22 curve 23 step 25 step 27 step 29 step 31 storage unit 33 step 35 warning unit 37 step 39 step 41 step p pressure p.sub.11, p.sub.12, p.sub.13 pressure limiting value p.sub.21, p.sub.22, p.sub.23 pressure limiting value crank angle .sub.1, .sub.2, .sub.3 crank angle limiting value