Abstract:
An arrangement is provided for determining the oil consumption of an oil-lubricated machine. The arrangement includes an oil circuit, which leads from an oil tank via a start line to the oil-lubricated machine and back, via a return line to the oil tank, and a balance for determining the weight of oil in the oil tank. A device for heating oil is assigned to the start line in such a way that the oil is heated to a predeterminable operating temperature for the oil-lubricated machine before reaching the oil-lubricated machine. A method for determining oil consumption is also provided.

Description:
BACKGROUND AND SUMMARY 
     The invention concerns an arrangement and method for determining the oil consumption of an oil-lubricated machine, in particular, a compressive oil-lubricated machine, such as an internal combustion engine, a compressor, a turbocharger, a pump, etc. 
     Such an arrangement is known for example from DE 20 2005 008 511 U1, in which an oil circuit is provided which leads from the oil pan of an internal combustion motor via an outer oil tank back to the oil pan. On the basis of this forced path of the oil circuit conclusions regarding oil consumption can be drawn via a gravimetric recording of the oil volume inside the oil tank. 
     A disadvantage of the known oil consumption determination emerges, mainly at the beginning of the measurement procedure, i.e., during the start-up phase of the internal combustion motor, in that large measurement fluctuations arise, which permit conclusions as to the oil consumption only conditionally, especially for the start activity of the combustion motor. Such measurement fluctuations are gathered from test results which are stated in  FIG. 2  of the above-mentioned DE 20 2005 008 511 U1. 
     Furthermore, it must be observed that the oil consumption values calculated by means of the known measuring device arrangement on the whole were lower than the actual oil consumption in ordinary operation of the internal combustion engine when empirically ascertained. 
     It is desirable to improve the arrangement to determine the oil consumption of an oil-lubricated machine, so that oil consumption measurement can be carried out more precisely in the start-up phase of the internal combustion engine as well. 
     A device for heating oil according to an aspect of the present invention is assigned to the start line in such a way that oil is heatable to a predeterminable operating temperature, which preferably corresponds to the optimal operating conditions of the machine, before reaching the machine. By heating the oil, practical conditions for oil consumption measurement are created, whereby unforeseeable measurement fluctuations still encountered in the prior art can be equalized. 
     For example, the heating device can be realized by means of suitable heating casings on the start line, which heat the flowing or standing oil volume in the start line until the desired operating temperature of the oil is reached. 
     In order, however, to provide a near-operation simulation of the oil circuit during the preheating phase as well, the oil circuit arrangement can have a bypass-line to short-circuit the start line or feed line and the return line, for example, to separate the working machine from the oil circuit. By means of the bypass line, the oil inside the oil circuit can be heated while maintaining the flow of oil, until the desired operating temperature for all oil in the oil circuit is reached. Preferably, the bypass line is connected to the start or return line upstream of the internal combustion engine via a 3-way valve. The 3-way valve can be controlled in such a way that the start line is fully blocked up to the oil-lubricated machine and the entire oil flow reaches the return line via the bypass line. In this way the entire oil volume in the start and return line and in the oil tank is heated by the heating device to the preferred prescribed operating temperature approximately equally. 
     In a preferred embodiment of an aspect of the invention, a temperature sensor for determining oil temperature is arranged, preferably directly upstream of the heating device, in order to provide data to a temperature regulator for regulating activation of the heating device. 
     Furthermore, a pressure sensor for determining oil pressure can be arranged upstream of the heating device. In the process, the pressure sensor is connected to a pressure regulator, which activates the oil pump built into the start line. In order to prevent incoming oil from flowing back into the oil tank when there are pressure fluctuations in the conduit system, preferably a non-return valve can be built into the intake line. In this way weight fluctuations in the precision balance can be avoided. With the help of this arrangement the necessary oil pressure can also be adjusted with the help of a frequency converter, which can regulate the speed of an oil pump. 
     Preferably, a further pressure sensor for determining oil pressure is arranged upstream of the working machine and downstream of the heating device, in order to register the effective oil pressure before the machine is reached, and to be able to control it. 
     In an alternative or additional implementation of an aspect of the invention, in order to increase the precision of the oil consumption determination, the generic arrangement is provided with a blow-by gas passage which is attached to the oil circuit. The blow-by gas passage should lead blow-by gas created by the machine away from the oil circuit. The oil particles contained in the blow-by gas are separated by a filtration system in order to be able to determine their weight. In normal operation, the blow-by gas would be fed back to the machine. In the invention, the weight calculated from the blow-by gas is computed, whereby actual oil consumption can be calculated. 
     Preferably, the blow-by gas passage discharges upstream of the combination of the bypass line and the return line, before the bypass line and the return line meet, in order to affect the oil circuit as little as possible. 
     In order to realize adequate diversion of the blow-by gas, preferably a blow-by gas pump is arranged in the blow-by gas passage. 
     In a preferred embodiment of an aspect of the invention, there is at least one filter with a specially assigned magnet valve upstream of the blow-by gas pump. Alternatively, there can be two filters connected parallel to each other, each with a specially assigned magnet valve, upstream of the blow-by gas pump. 
     In addition, an aspect of the invention concerns a device for determining the oil consumption of an oil-lubricated machine, in which oil is pumped in from an oil tank and out to the working machine, and from there is led back to the oil tank, whereby the weight of the oil volume found in the oil tank is continuously measured gravimetrically. According to the invention, the oil is heated before passing through the machine to a predeterminable operating temperature for the working machine. 
     Preferably, the oil pressure and the oil temperature are adjusted to the operating conditions of the machine, before the oil consumption determination process is initiated. 
     Preferably, the blow-by gases with oil particles contained therein are led to an oil circuit which leads from the oil tank to the machine and back to the oil tank. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages, characteristics and features of the invention will be clearly shown through the following description of a preferred embodiment of the invention with the help of the attached diagrams, in which: 
         FIG. 1  shows a schematic diagram of the arrangement according to the invention to determine the oil consumption of a turbocharger; 
         FIG. 2  shows a perspective schematic diagram of an example for a heating system to be assembled in the arrangement according to  FIG. 1 ; and 
         FIG. 3  shows a perspective schematic diagram of a conduit system able to be inserted in the arrangement according to the invention with a bypass. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , the overall arrangement for determining the oil consumption of a turbocharger according to the invention is marked with the reference number  1 . The arrangement  1  comprises an oil pan  3  in which oil  5  is stored in sufficient volume. The oil pan  3  stands on a precision balance  7  with a maximum load of, for example, 36 kg, with an accuracy of at least 1/10 g. To conduct weight data processing, the precision balance  7  is joined electrically to a data capture system  9 , in which the weight measurement data is continuously recorded, processed and stored. 
     The oil consumption determination arrangement  1  also has an oil circuit  11 , the oil flow of which is indicated with arrows O. The oil circuit  11  leads from the inside of the oil pan  3  via a start line  13  to a pump  15  which is operated by a motor M, and which supplies the intake pressure to produce the oil flow. An intake filter  17  is provided for the infeed to the start line  13  on the side of the oil pan, which purifies the oil to be taken in before entering the start line. Directly downstream from the intake filter  17 , a non-return valve  19  is integrated in the start line  15  [sic], which should prevent a backflow of oil that has been taken in when there are pressure fluctuations in the conduit system of the oil circuit  11 . Downstream of the pump  15 , a pressure sensor  21  is installed, which records oil pressure. The recorded oil pressure data of the pressure sensor  21  is transmitted by a pressure regulator  23  which regulates the oil pressure according to the necessary operating conditions for the off-gas turbocharger and controls the pump  21  via the controlling element M. 
     Downstream of the pressure sensor  21  is a heating device  25  which the start line  13  encircles area by area and that heats the oil held within, before it reaches a 3-way valve  27  arranged downstream of the heating device. In the direction of flow, the 3-way valve bifurcates the start line into a turbo charger line  31  and bypass line  29 . The turbo charger line  31  leads to the turbo charger  33 . From the turbo charger  33  a discharge line  35  leads via a 3-way valve  36  back to a return line  37 , which flows back in the oil pan  3 . The bypass line  29  flows in the 3-way valve  36 , so that with the bypass line  29  the start line  13  and the return line  37  are “short-circuited” by going around the turbo charger  33  and the discharge line  35 . 
     A blow-by gas line  41  extends from the bypass line  29  and the 3-way valve  36 . 
     The blow-by gas line  41  splits downstream into a parallel circuitry with two parallel sections of line, in each of which is arranged a filter  45  and a magnet valve  47 . Following the parallel switching line, a blow-by gas pump  49  is attached, which operates the diversion of blow-by gas corresponding to the flow direction S. 
     Below, the mode of operation of the arrangement for determining oil consumption  1  according to  FIG. 1  will be described. 
     In a start phase in which the oil in the arrangement for determining oil consumption is still cold, the 3-way valve  27  is connected in such a way that the start line  13  and the return line  37  is short-circuited [sic], and the turbo charger is shut off from the oil circuit  11 . After activation of the heating device  25 , the heating device  25  heats the passing oil until it is heated to the desired operating temperature of the turbo charger  33 . Finally, the 3-way valve  27  is shut off, so that the internal combustion engine with off-gas turbo charger can be put into operation and adequate oil lubrication is guaranteed. 
     During the start phase and the normal operation of the turbo charger  33 , the oil volume inside the oil pan  3  is continuously recorded gravimetrically and delivered to the data capture system  9 . 
     In order for the oil to have the desired operating temperature, downstream of the heating device  25  and upstream of the 3-way valve  27 , a temperature and pressure sensor  53  is provided, which is connected to a temperature regulator which controls the heating device  25 . 
     It was determined that with the method according to the invention of preheating the oil of the oil circuit  11 , measurement fluctuations during the start-up phase of the turbo charger can be avoided and exact information regarding oil consumption is possible, including when the turbo charger is in a critical operating situation. 
     By means of the blow-by gas line  41 , the blow-by gas, which contains oil particles, is pumped out with a pump  49  and filtered in the filters  45 . In this way, the oil particles which would be otherwise lost in the blow-by gas are not incorrectly incorporated into the account of the oil consumption. 
     In  FIG. 2 , a heating device  25  according to the invention is depicted in detail. The heating device  25  consists essentially of or comprises a high quality steel spiral pipe  53  encased in a heating tube. The heating tube is adjusted, by means of the temperature measurement value calculated by the temperature sensor  53 , to the desired operating temperature for the internal combustion engine by the temperature regulator  51 , coded via a display and adjustment knob. The inner wall of the conduit through which the oil passes, as indicated by the arrows, is provided with a slick surface of the type that minimizes flow loss and prevents air bubble formation within the tube. 
     In the area of the heating device  25  the conduit spirals up steadily in order to prevent air from being trapped in the area of the heating device. In this way, a faster heat input can be achieved in the oil to be heated along the heating device. Simultaneously, this keeps the construction of the arrangement  1  compact. 
     In  FIG. 3  a part of the oil circuit flow  11  according to the invention with the heating device  25  is schematically presented. Directly past the heating device  25 , a cross line  61  forming the bypass line is attached to the start line  13 , which features a shut-off valve  63  in the middle for opening and closing the bypass line. The cross line  61  flows into the return line  35 . Particularly in the area of the heating line and also in other parts of the oil circuit flow  11 , heed should be paid to forming as few stage bays or undercutting transitions as possible, in order to avoid fluidic holdups and dead areas for the oil. 
     The features disclosed in the foregoing description, as well as in the diagrams and claims, can be relevant both singly and in any combination for the realization of the invention in the various embodiments. 
     LIST OF REFERENCE NUMBERS 
     
         
           1  Device for determining oil consumption 
           3  Oil pan 
           5  Oil 
           7  Precision balance 
           9  Data capture system 
           11  Oil circuit 
           13  Start line 
           15  Pump 
           17  Intake filter 
           19  Non-return valve 
           21  Pressure sensor 
           23  Pressure regulator 
           25  Heating device 
           27 ,  36  3-way valve 
           29  Bypass line 
           31  Turbo charger line 
           33  Turbo charger 
           35  Discharge line 
           37  Return line 
           41  Blow-by gas line 
           43  3-way valve 
           45  Filter 
           47  Magnet valve 
           49  Blow-by gas pump 
           51  Temperature regulator 
           53  T-sensor [Temperature sensor] 
           61  Cross line 
           63  Shut-off valve 
         M Controlling element 
         O Oil flow 
         S Blow-by gas flow