Abstract:
Procedure to operate a combustion motor in the event of damage, whereby the thermoelectric voltage of a lubricant interruption on parts moving relative to each other and made of different, electrically conducting materials, is used to initiate an alarm signal, in that upon the appearance of such an alarm signal at least one operating parameter of the combustion engine is changed until the alarm extinguishes and the combustion motor is then further operated in a reduced operational state.

Description:
[0001]     This application claims priority of application CH 0 1513/05 having a priority date of Sep. 16, 2005, the disclosure of which is hereby incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The invention involves a procedure to operate a combustion engine in the event of damage, as well as a device to perform the procedure.  
       BACKGROUND OF THE INVENTION  
       [0003]     Procedures and devices to monitor friction bearings, especially in a reciprocating piston engine, like a combustion engine, are known from EP-B-0 141 348. On the basis of the monitoring of the main bearing of a crankshaft of a combustion engine a procedure and a device are described for monitoring the lubrication at the contact point between two parts made of different, electrically conducting materials moving relative to each other and insulated form each other by a lubrication film. The two parts lie in an electrical current with a voltage source and an external connection and which flows through the lubrication location itself. The circuit resistance which reduces with the tearing off of the lubricating film, on the one hand, and the thermoelectric voltage, on the other hand, which serves as a galvanic voltage source and appears with the tearing off of the lubricating film at the contact location because of frictional heat, are used in order to produce a current flow, which acts as a control or alarm signal across the external electrical connection of the electrical circuit at the appearance of a large area of metallic touching of the two friction bearing parts caused by a lack of lubrication and thus signals heat damage. The connection of the electric circuit is constructed as a resistance which is electrically adapted to the large area contact location. The voltage drop appearing at the resistance of the external connection is measured and used to initiate a control signal. The control signal serves, for example, to stop the combustion engine or activate an alarm device. It is useful to so design the procedure and device, that in the event of a voltage spike appearing for a short time, the control signal activation is suppressed until a previously determined time frequency of the voltage peaks and/or an increasing tendency of the amplitude occurs. No information about a suitable method of further operating the combustion engine can be found in the document.  
         [0004]     EP 1 171 695 contains a further development of the previously described monitoring, in that the damage location can be localized. Here, too, there is no information about a continued operation of the combustion motor in the event of damage.  
       SUMMARY OF THE INVENTION  
       [0005]     It is the goal of the invention to provide a procedure and device to operate a combustion engine in the event of damage.  
         [0006]     The goal is achieved by procedures to operate a combustion engine, as well as devices to perform the procedures disclosed herein.  
         [0007]     Surprisingly, it was determined that the monitoring of damage to a combustion engine by means of the thermoelectric voltage of a lubrication interruption on parts moving relative to each other and made of different, electrically conducting materials, which previously was used to initiate an alarm signal or shut off a combustion engine, reacts so quickly, that it is also suitable for a further operation of the combustion engine in a reduced mode. In the process at least one operating parameter of the combustion engine is changed upon the appearance of an alarm signal, until the alarm signal extinguishes, so that the combustion engine can be further operated in this reduced mode.  
         [0008]     Preferably, the thermoelectric voltage from the friction bearings is used as the alarm signal. However, it is also possible to alternatively or supplementally use thermoelectric voltages from cylinder surfaces for the alarm signal.  
         [0009]     It is useful, if in the event of an alarm, different operating parameters are changed and then the most effective is used for the reduced operation. The adjustment of the operating parameter can occur manually in the simplest case. The configuration whereby the operating parameter is changed by means of a control device, however, is especially advantageous.  
         [0010]     One embodiment of the invention provides a suitable device to perform the procedure, whereby an acquisition device is used, which is connected, on the one hand, by means of lines with the housing and, on the other hand, with the motor shaft of the combustion motor and emits an alarm signal upon the appearance of a significant thermoelectric voltage. The acquisition device is connected with a control device to control the regulating devices for the operating parameters of the combustion engine. It is especially advantageous, if the control device contains a computer which is connected to the regulating devices, in order to be able to determine the optimal operating parameter for the reduced operation for every different instance of damage. 
     
    
     SHORT DESCRIPTION OF DRAWINGS  
       [0011]     Execution models of the invention are described in more detail using schematic depictions; shown thereby are:  
         [0012]      FIG. 1  Depiction of a vertical cut through a three-cylinder combustion motor;  
         [0013]      FIG. 2  Main bearing of a crankshaft of the combustion engine of  FIG. 1  in a larger scale and in a vertical cut;  
         [0014]      FIG. 3  Depiction of a control device to control regulation devices for the operating parameters of a combustion engine. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     This invention proceeds from the state of knowledge of EP-B-0 141 348 and EP-B-1 171 695.  FIG. 1  shows a depiction of a reciprocating combustion motor with, for example, three cylinders that operate according to the 4-cycle principle, which means one complete cycle occurs over two crankshaft revolutions or an angle of 720 degrees. The combustion motor contains a crankshaft  1  of a crank mechanism for the three cylinders Z 1 , Z 2 , Z 3 . The crank mechanism is lodged in friction bearings, so called main bearings  2 , in which trunnions  2   a  rest in bearing seats  3 , as can be especially seen in  FIG. 2 . To obtain good slide characteristics the bearing seats  3  are coated with, for example, a white alloy layer  4  on the side resting on the trunnions  2   a , whereby a lubrication film  5  located between this white alloy layer  4  and the trunnion  2   a  prevents an overheating of the friction bearings. The bearing seats  3  are mounted on pedestals  6  which form a single piece with a common housing  7 .  
         [0016]     The crankshaft  1  contains a crank pin  8  for each cylinder Z 1 , Z 2 , Z 3 , to which a connecting rod  9  is attached across a big end bearing  10 . The connecting rod  9  is connected across another friction bearing  11  with a piston pin  12  of a piston  13 , which is guided up and down in cylinder Z 1  or Z 2  or Z 3  along the cylinder running surfaces  13   a . The construction of the big end bearing  10  and the friction bearing  11  of the piston pin is similar to the main bearing  2  of the crankshaft  1 .  
         [0017]     Now in order to acquire at any friction bearing the thermoelectric current resulting from the heat because of the interrupted lubrication film and finally the pairing of different metals at the friction bearings, the combustion engine is equipped with an acquisition device  14  which contains a display unit  15 . On the one hand, the acquisition device  14  is connected to the housing  7  by means of a connecting line  16  and across a connection line  17  with a collector  18  that is electrically connected to the crankshaft  1 . Parallel to the acquisition device  14  the connecting lines  16 ,  17  are short circuited across a low ohm resistance  19 . Because of the thermoelectric voltage produced by galvanic means in the friction bearing, a thermoelectric current flow in the low ohm electrical circuit  16 ,  17 ,  18 ,  19 , which initiates a voltage drop at the resistor  19 . This signal is processed in the acquisition device  14  and sent to the display device  15 .  
         [0018]     The acquisition device  14  is equipped with a means  20  of determining the rotational angle of the crankshaft  1 . In the process the means  20  manifest, for example, a pulse generator  21  that is connected to the crankshaft  1 , whose angle-dependent signals, for example a bar code on the circumference, are acquired by a sensor  22  and sent across a line  23  to an acquisition device  14 . In addition, the acquisition device  14  is equipped with the means  24  to determine the ignition sequence in cylinders Z 1 , Z 2  and Z 3 . To accomplish this, there is, for example, a line  25  which is connected with an ignition distributor  26  that sends the ignition current through an ignition wire  27  to the individual spark plugs  28 . The means  20  to determine the rotational angle or the means  24  for the acquisition of the ignition sequence can also be realized by an electronic control device for the combustion engine, the latter especially when the combustion motor is a diesel engine which does not have any spark plugs, but instead is equipped with a fuel injection or is aligned on the upper dead spot of the first cylinder Z 1  through the calibration of the pulse generator.  
         [0019]     Based on the alarm signal of the display device  15 , the operating parameters of the combustion motor can then be manually changed until the alarm signal of the display device  15  extinguishes. Then the combustion engine can continue in this reduced operational state until a new alarm signal appears, whereby the reduced operational state of the combustion engine must be further reduced until the alarm again disappears. It has been seen that the reaction times of the acquisition device are so short, that the combustion engine can be further operated in the reduced mode without any damage. Such reaction times amount, for example, to only a few seconds. It is especially advantageous, however, if the device to perform the procedure, which is schematically depicted in  FIG. 3 , is present. In this process, the acquisition device  14  or the display device  15  are connected by means of a line  30  with a control device  31 , which in turn is connected with the regulating devices for the operating parameters of the combustion engine. As an example, a regulating device  33  is attached here by way of a line  32  to control the injection quantity of fuel into the cylinder. A regulating device  35  is attached across a line  34  which serves to change the injection time for the fuel in the cylinder. A regulating device  37  is attached by a line  36 , by means of which the oil pressure for the lubrication of the friction bearing can be adjusted. In addition, a regulating device  39  can be attached by means of a line  38  with which, for example, the power for an attached unit supplied from the combustion motor can be reduced. By means of regulating devices, the injection quantity and the time of the injection of the fuel can be changed as desired, as well as increasing or reducing the oil pressure for the lubrication of the friction bearing. The power from the combustion engine for an attached unit such as a generator for example, can be reduced.  
         [0020]     In the procedure of the invention, it is basically not necessary to know which damage occurred where in the combustion engine; each instance of damage which initiates a thermoelectric current can cause a reduction of the operational mode. It is, however, more advantageous if the acquisition device simultaneously signals the location of the damage, as described in EP 1 171 695. Then there can be a change of the basic, primary operating parameters which are particularly critical for such a case of damage. It is advantageous, for example, in the case of bearing damage to the main bearing, to reduce the revolutions or the load. In the case of damage to a cylinder running surface, it is primarily recommended to increase the quantity and/or the pressure of the lubricant.  
         [0000]     Figure Reference List  
         [0021]      1  Crankshaft  
         [0022]      2  Main bearing  
         [0023]      2   a  Trunnion  
         [0024]      3  Bearing seat  
         [0025]      4  White alloy layer  
         [0026]      5  Lubricant film  
         [0027]      6  Pedestal  
         [0028]      7  Housing  
         [0029]      8  Crank pin  
         [0030]      9  Connecting rod  
         [0031]      10  Big end bearing  
         [0032]      11  Frictional bearing  
         [0033]      12  Piston pin  
         [0034]      13  Piston  
         [0035]      13   a  Cylinder running surface  
         [0036]      14  Acquisition device  
         [0037]      15  Display device  
         [0038]      16  Connecting line  
         [0039]      17  Connecting line  
         [0040]      18  Collector  
         [0041]      19  Resistance  
         [0042]      20  Means for rotational angle  
         [0043]      20   a  Means for rotational angle  
         [0044]      21  Impulse generator  
         [0045]      22  Sensor  
         [0046]      23  Line  
         [0047]      24  Means for ignition sequence  
         [0048]      25  Line  
         [0049]      26  Ignition distributor  
         [0050]      27  Ignition wire  
         [0051]      28  Spark plug  
         [0052]      30  Line  
         [0053]      31  Control device  
         [0054]      32  Line  
         [0055]      33  Regulating device for injection quantity  
         [0056]      34  Line  
         [0057]      35  Regulating device for injection time  
         [0058]      36  Line  
         [0059]      37  Regulating device for oil pressure  
         [0060]      38  Line  
         [0061]      39  Regulating device for power removal  
         [0062]     Z 1  First cylinder  
         [0063]     Z 2  Second cylinder  
         [0064]     Z 3  Third cylinder