Method and control unit for operating a diesel internal combustion engine or a dual-fuel internal combustion engine operated in the diesel mode

Abstract

A method for operating an internal combustion engine wherein the internal combustion engine to be operated is supplied with lubricating oil via an oil circuit. A measurement value of a total base number and/or a measurement value of the viscosity of the lubricating oil currently used in the oil circuit for the lubrication is detected. Dependent on the established measurement value of the total base number and/or dependent on the established measurement value of the viscosity an exchange oil quantity for the oil circuit is determined. Currently used lubricating oil to an extent corresponding to the exchange oil quantity is removed from the oil circuit. New lubricating oil to an extent corresponding to the exchange oil quantity is supplied to the oil circuit.

Claims

1. A method for operating a diesel internal combustion engine or a dual-fuel internal combustion engine operated in a diesel operating mode, comprising: supplying the internal combustion engine with lubricating oil via an oil circuit; detecting a measurement value of a total base number and/or a measurement value of a viscosity of the lubricating oil currently used in the oil circuit for lubrication; determining an exchange oil quantity for the oil circuit based at least in part on: the measurement value of the total base number and/or the measurement value of the viscosity; controlling a first valve to remove currently used lubricating oil to an extent corresponding to the exchange oil quantity directly from the oil circuit into a collection tank; and controlling a second valve to add new lubricating oil to the extent corresponding to the exchange oil quantity directly to the oil circuit from an oil storage tank.

2. The method according to claim 1, further comprising: determining based at least in part on the measurement value of the total base number and the measurement value of the viscosity the exchange oil quantity for the oil circuit.

3. The method according to claim 1, wherein the measurement value of the total base number of the lubricating oil currently used in the oil circuit for the lubrication is detected with a first sensor.

4. The method according to claim 3, wherein the measurement value of the viscosity of the lubricating oil currently used in the oil circuit for the lubrication is detected with a second sensor.

5. The method according to claim 1, wherein the exchange oil quantity for the oil circuit is determined based at least in part on the measurement value of the total base number and/or the measurement value of the viscosity as a function of a characteristic map or characteristic curve.

6. A control unit configured to operate a diesel internal combustion engine or a dual-fuel internal combustion engine operated in a diesel operating mode, wherein the control unit is configured to: receive, from a sensor, a measurement value of a total base number and/or receive from a sensor a measurement value of a viscosity of lubricating oil currently used for lubricating the internal combustion engine in an oil circuit; determine an exchange oil quantity based at least in part on the measurement value of the total base number and/or the measurement value of the viscosity; emit a control signal, as a function of which, a first valve is opened and currently used lubricating oil is removed directly into a collection tank from the oil circuit to an extent corresponding to the determined exchange oil quantity; and emit a control signal as a function of which a first valve is opened and new lubricating oil to an extent corresponding to the determined exchange oil quantity is suppliable to the oil circuit directly from an oil storage tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred further developments of the invention are obtained from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail by way of the drawing without being restricted to this. There it shows:

(2) The FIGURE is a diagram of an internal combustion engine.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(3) The invention relates to a method and to a control unit for operating a diesel internal combustion engine or a dual-fuel internal combustion engine operated in the diesel operating mode.

(4) The FIGURE shows a highly schematised diagram of an internal combustion engine 1, which comprises multiple cylinders 2 and an oil circuit 3. The oil circuit 3 serves for supplying in particular the cylinders 2 of the internal combustion engine 1 with lubricating oil, wherein the lubricating oil is supplied to the cylinders 2 of the internal combustion engine 1 via an advance 4 and discharged from the same via a return 5.

(5) According to one aspect of the invention it is proposed to detect a measurement value of the total base number (TBN) and/or a measurement value of the viscosity of the lubricating oil currently used in the oil circuit 3 for the lubrication. The measurement value of the total base number of the lubricating oil currently used in the oil circuit 3 for the lubrication is detected with the help of a first sensor 6. The measurement value of the viscosity of the lubricating oil currently used in the oil circuit 3 for the lubrication is detected with the help of a second sensor 7.

(6) The arrangement of the sensors 6 and 7 in the oil circuit is arbitrary. The two sensors 6 and 7 can also be combined into a unit.

(7) Dependent on the established measurement value of the total base number and/or dependent on the established measurement value of the viscosity, an exchange oil quantity for the oil circuit 3 is determined. To this end, the two sensors 6, 7 transmit their respective measurement value to a control unit 12, which dependent on the measurement value of the total base number and/or dependent on the measurement value of the viscosity determines the exchange oil quantity for the oil circuit 3.

(8) According to one aspect of the invention, currently used lubricating oil is removed from the oil circuit 3 to an extent corresponding to the determined exchange oil quantity, furthermore, new lubricating oil to an extent corresponding to the determined exchange oil quantity is supplied to the oil circuit 3. The control unit 12 determines control variables as a function of which this oil exchange is carried out.

(9) Accordingly, the FIGURE shows a first valve 8 which can be directly or indirectly controlled by the control unit 12 subject to the intermediate connection of a further control unit, in order to remove lubricating oil to the extent corresponding to the determined exchange oil quantity from the oil circuit 3 and collect the same in a collection tank 10. Furthermore, the FIGURE shows a further valve 9 which can be likewise controlled emanating from the control unit 12 in order to supply the oil circuit 3 with new lubricating oil which is kept ready in a storage tank 11.

(10) With the invention it is proposed accordingly to remove a defined oil quantity from the oil circuit 3 dependent on the measurement value of the total base number and/or dependent on the measurement value of the viscosity of the lubricating oil currently used in the oil circuit 3 for the lubrication and exchange the same against new lubricating oil, namely to the extent of the exchange oil quantity established as a function of the respective measurement value.

(11) In this way, an oil consumption can be reproduced in the region of the cylinders 2. A defined exchange oil quantity of new oil can be continuously supplied in order to maintain the lubricating oil characteristics of the lubricating oil and render a complete oil change on the internal combustion engine 1 superfluous.

(12) The determination of the exchange oil quantity for the oil circuit dependent on the established measurement value of the total base number and/or dependent on the established measurement value of the viscosity takes place preferentially dependent on the characteristic diagram or characteristic curve. The characteristic map or the characteristic curve is stored in the control unit 12. For different support points of measurement values, exchange oil quantities are stored. Interpolation or extrapolation can be performed between individual support points.

(13) The method is employed with diesel internal combustion engines or dual-fuel internal combustion engines operated in the diesel operating mode. In particular, the exchange oil quantity is determined dependent on the two measurement values, i.e. dependent both on the total based number and also dependent on the viscosity of the lubricating oil. This procedure is particularly preferred for diesel internal combustion engines or dual-fuel engines operated in the diesel operating mode.

(14) One aspect of the invention, furthermore, relates to a control unit 12 for carrying out the method. The control unit is equipped to carry out the method described above on the control side. To this end, the control unit 12 comprises data interfaces in order to exchange data with the assemblies involved in carrying out the method according to the invention, in particular with the sensors 6 and 7 and the valves 8 and 9. Furthermore, the control unit 12 as assembly on the hardware side comprises a processor for the data processing and a memory for data storage. Furthermore, the control unit 12 comprises means on the software side which are program modules which serve for carrying out the method according to the invention.

(15) The control unit 12 receives from the respective sensors 6, 7 the respective measurement value, preferentially the measurement value of the total base number from the sensor 6 and the measurement value of the viscosity from the sensor 7. Dependent on the respective measurement value, the control unit 12 determines the exchange oil quantity. Dependent on the exchange oil quantity, the control unit 12 emits control signals, as a function of which the oil exchange takes place, as a function of which accordingly currently used lubricating oil is removed from the oil circuit 3 and new lubricating oil supplied to the oil circuit 3.

(16) The invention relates in particular to the sector of so-called large engines or large internal combustion engines whose cylinders have piston diameters of more than 140 mm, in particular of more than 175 mm. Such large internal combustion engines are for example marine engines. In the invention, these are embodied as diesel internal combustion engines or as dual-fuel internal combustion engines operated in the diesel operating mode. As fuel, such internal combustion engines combust gaseous fuel such as natural gas or liquid fuel such as methanol. Internal combustion engines combusting gaseous fuel are also referred to as gas engines.

(17) Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.