Method of operating a drive of a mining machine and mining machine

Abstract

The invention relates to a method of operating a drive of a mining machine, in particular of a mining excavator, a mining loader, or a mining tipper, comprising at least one diesel engine and at least one exhaust gas purification device. The invention is further directed to a corresponding mining machine that can be operated in accordance with the method.

Description

- 1 - METHOD OF OPERATING A DRIVE OF A MINING MACHINE AND MINING MACHINE FIELD OF THE INVENTION The invention relates to a method of operating a drive of a mining machine, in particular of a mining excavator, a mining loader, or a mining tipper, comprising at least one diesel engine and at least one exhaust gas purification device. The invention is further directed to a corresponding mining machine that can be operated in accordance with the method. BACKGROUND Mining machines and methods of operating them are known from the prior art in which an exhaust aftertreatment of exhaust gases takes place that are emitted by a diesel engine of the mining machine. The exhaust gas systems of, for example, diesel engines of the "Tier 4" generation can comprise an exhaust gas purification device such as an SCR device (selective catalytic reduction) that converts NOx gases into nitrogen and steam. At low operating temperatures, non-combusted hydrocarbon deposits can remain on the catalysts used in this process. These deposits oxidize over time and can form soot. These soot deposits can in turn result in a clogging of a particle filter and thereby to a reduction in the efficiency of the exhaust gas purification device or even to its destruction. A method of operating an internal combustion engine is known from US 9,032,717 B2 in which a diesel particulate filter is heated, with a regeneration taking place by a post-injection of fuel into the exhaust gases. CA 3034312 2019-02-20 - 2 - US 8,230,679 B2 describes a method of operating an internal combustion engine in which the exhaust temperature can be increased by influencing the engine performance. The document concentrates solely on the engine control, with relevant parameters of an exhaust gas purification device and of a radiator circuit being left out of account. SUMMARY OF EMBODIMENTS OF THE INVENTION Against this background, it is the object of the present invention to provide an improved method of operating the drive of a mining machine and to provide a corresponding mining machine, wherein in particular the contamination of the exhaust gas purification device can be reduced. A method of operating a drive of a mining machine is accordingly provided, wherein the mining machine can in particular be a mining excavator, a mining loader, or a mining tipper. In accordance with the method, a mining machine is operated by at least one diesel engine and at least one exhaust gas purification device. The method comprises the steps: = determining the coolant temperature of the diesel engine; = determining the speed of the diesel engine; = determining the contamination of the exhaust gas purification device by soot and / or non-combusted hydrocarbons; and = setting a new speed of the diesel engine greater than its idling speed in dependence on the determined values. It is possible by setting a new speed, in particular a higher speed, to carry out a purification procedure of the exhaust gas purification device that is also described as regeneration. This purification procedure can comprise the raising of the temperature of a catalyst that can be part of the exhaust gas purification device. CA 3034312 2019-02-20 - 3 - Non-combusted hydrocarbons are removed from the surface of the catalyst by the raising of the temperature and concentrated soot deposits are oxidized in the exhaust gas purification device or in the SCR device. It is conceivable in a preferred embodiment of the invention that the speed of the diesel engine is set to a predefined speed, in particular of approximately 1200 r.p.m. The speed value is to be understood as an approximate, exemplary value that is above a normal idling speed. The new speed value can be, for example, between 1100 and 1300, between 1000 and 1400, or between 900 and 1500 revolutions per minute. The non-combusted hydrocarbons can be any non-combusted fuel residues that were not fully combusted in the combustion process taking place in the diesel engine and that can therefore be deposited in the downstream exhaust gas duct of the diesel engine. Unlike the methods known from the prior art in which exhaust throttle valves are, for example, used for the purification of exhaust gas purification devices, the invention allows the regeneration of exhaust gas purification devices or SCR devices and / or their filters to be effected without the use of additional or supplementary mechanical components, with the temperature of the catalyst also being able to be set without a direct intervention of a user or of an operator of the corresponding device. It is conceivable in a further preferred embodiment of the invention that the new speed of the diesel engine is set when the coolant temperature is higher than a predefined temperature and is in particular higher than 50 C. This threshold temperature is to be understood as an exemplary value. It can hereby advantageously be ensured that the method in accordance with the invention is not carried out in a state of the diesel engine that is too cold and that thereby disadvantages are involuntarily effected in the operation of the diesel engine. CA 3034312 2019-02-20 - 4 - It is conceivable in a further preferred embodiment of the invention that the new speed of the diesel engine is set when the initially determined speed of the diesel engine is a predefined idling speed, in particular of approximately 800 revolutions per minute. This threshold value of approximately 800 r.p.m. is not to be understood as restrictive and can comprise values between 700 and 900, and further preferably, between 600 and 1000 r.p.m. If a speed is determined that corresponds to an idling speed, a regeneration or purification of the exhaust gas purification device can be carried out under the given circumstances by the raising to the new speed for which otherwise sufficient thermal energy would not be available in the range of the low idling speed. It is conceivable in a further preferred embodiment that the new speed of the diesel engine is set when the determined contamination exceeds a settable threshold value. The settable threshold value or also the settable threshold values can here be compared with the determined values of the contamination and this comparison can be used as a regulation criterion for carrying out the method in accordance with the invention. Two different threshold values can in particular be used, one for the contamination with soot and the other for the contamination with non-combusted hydrocarbons. A large number of methods and apparatus are known from the prior art for the determination of the contamination that do not themselves represent the core of the invention and to which reference is therefore only marginally made. It is conceivable in a further preferred embodiment that the determined contamination with soot and / or non-combusted hydrocarbons is displayed. A corresponding display device can be provided for this purpose that displays the current degree of contamination to an operator. It is alternatively or additionally possible on the basis of this display that an operator triggers or controls the method in accordance with the invention by a manual control signal. The triggering or control can take place manually or alternatively thereto automatically. A corresponding input device can be provided for this purpose to input a corresponding control signal. CA 3034312 2019-02-20 - 5 - It is conceivable in a further preferred embodiment that the setting of the new speed is ended when the determined contamination is close to or at 0% and / or when a user of the mining machine manually changes the speed of the diesel engine. The method in accordance with the invention in accordance with claim 1 can run repeatedly or in a loop so that the parameters determined therein are determined continuously or repeatedly. The method can also continue to be carried out after a new speed has been set. It can be determined here in connection with the features of claim 7 whether the contamination falls or reaches a sufficiently low value after which the setting of the new speed can be ended and, for example, an old speed or a new speed can be set. It is also conceivable that the method furthermore comprises the step: determining the exhaust gas temperature of at least one portion of the diesel engine. It is conceivable in a further preferred embodiment that the determination of the contamination and / or the setting of the new speed takes place automatically or manually, with provision in particular being made that this is enforced by a manual actuation in a servicing phase of the mining machine. The at least one portion of the diesel engine can, for example, be a partial region, some of the cylinders, or another subsection of the diesel engine. It can in particular be a subsection of the diesel engine that has an exhaust gas routing that is at least partially separate from the rest of the diesel engine. The exhaust gas temperature and / or the further determined parameters such as the coolant temperature, the speed and / or the contamination of the exhaust gas purification device can also accordingly relate to a respective such subsection of the diesel engine or of the corresponding auxiliary unit. Said parameters can thus be determined separately for two or more subsections of the diesel engine or subsections of devices coupled to the engine and can also be compared with one another. Further regulation options can result from these comparisons of the parameters. CA 3034312 2019-02-20 - 6 - It is conceivable in a further preferred embodiment that the method furthermore comprises the step: setting at least one hydraulic pump and / or at least one fan of the diesel engine to full operating power. This setting of the hydraulic pump and / or of the fan can take place under the same conditions as the setting of the new speed. In addition to the fan and a hydraulic pump such as a coolant pump, further auxiliary units of the engine such as a hydraulic system of the mining machine can be regulated / controlled alternatively or additionally in dependence on the determined parameters. An increase in the operating temperature then takes place here when the power of the hydraulic system is increased. In the case of a V engine having two cylinder banks, the two banks can be separated individually. If only a single bank is operated that can in turn be operated at a higher power output, the operating temperature increases to a higher degree, which serves the regeneration in accordance with the invention. The choice of the operated bank can depend on the exhaust line to be purified. The invention is further directed to a mining machine, in particular to a mining excavator, a mining loader, or a mining tipper. BREIF DESCRIPTION OF THE DRAWINGS Further details and advantages of the invention are explained with reference to the embodiment shown in the only Figure. Figure 1 shows the schematic routine of the method in accordance with the invention of operating a drive of a mining machine having at least one exhaust gas purification device. DETAILED DESCRIPTION OF THE DRAWINGS Corresponding exhaust gas purification devices can be contaminated in the course of their operation. Different routines can take place in the exhaust gas purification device in dependence on the temperature. Non-combusted carbons can be CA 3034312 2019-02-20 - 7 - absorbed or adsorbed by the surface of a catalyst below 200 C. Soot can be formed in the exhaust gas purification device between 170 C and 270 C. No non- combusted hydrocarbons can be deposited in a neutral zone between 200 C and 250 C and nor can any regeneration of the exhaust gas purification device take place. A regeneration of the non-combusted hydrocarbons can take place above 250 C. A regeneration of soot can take place above 350 C. The exhaust gas purification devices therefore have to be purified in a temperature range of more than 250 C. In accordance with the invention, a determination is made in a first step A whether a coolant temperature of a diesel engine of the mining machine is above a predefined value of, for example, 50 C. Different or slightly deviating temperatures of between 45 C and 55 C or between 40 C and 60 C can also be considered as threshold values here. If this is not the case, step A is repeated until it is the case and a next step B is carried out. A determination is made in the second step B whether the diesel engine is operated at an idling speed of approximately 800 r.p.m. If the criteria checked in the two steps A, B apply or are present, a determination can be made in a next step C whether the contamination of the exhaust gas purification device with soot and / or non-combusted hydrocarbons is above specific threshold values such as 20% or 50% or above other threshold values. This determination can take place separately for two or more subsections of the diesel engine. The determined values or contaminations can accordingly also be compared or looked at separately from one another in the individual portions of the diesel engine. If it is, for example, determined that the contamination values determined in a first subsection of the diesel engine in step C are not above the predetermined values, a determination can then be made in a second subsection of the diesel engine in step C' whether the corresponding contamination values exceed the predetermined values in this subsection. If this likewise does not apply, the method can return to step B. If the contamination values determined in one of the steps C, C' are above the predetermined values, steps D, D' can be carried out to determine the exhaust CA 3034312 2019-02-20 - 8 - gas temperatures in the respective subsections of the diesel engine. The steps D, D can alternatively also be omitted or skipped and step E described further below can be directly carried out. The respective subsection of the diesel engine can be examined more closely with respect to its exhaust gas temperature in dependence on the portion of the diesel engine in which the first three criteria are satisfied, that is, in which the coolant temperature is above a threshold value, the speed of the diesel engine is in the range of a first speed, and the contamination with soot and / or non-combusted hydrocarbons is above specific threshold values. The new speed of the diesel engine can then be set in a step E as a response to the criteria A to C depending on whether the exhaust gas temperature in one portion of the diesel engine is greater or is the greatest or is, for example, more than 10 C higher than in the other subsections of the engine. Or other settings can be carried out at the respective subsection in steps X, X'. The other settings can be the deactivating of a bank or the separation of the banks in the case of a V engine or of another engine having two cylinder bank. Steps X, X' can also be omitted or skipped like steps D, D'. In addition, in step E, the hydraulic pump and the fan can also be set to a maximum operating power or other auxiliary units for improving the regeneration of the exhaust gas purification device can be set. If it is found in the further course of the method that the contamination with soot and / or non-combusted hydrocarbons is at 0% or is lower than a threshold value and / or if it is found that an operator is manually influencing the speed of the diesel engine, the at least partial automatic setting of the new speed in accordance with the method can be interrupted in a step F. Alternatively to this, the setting of the new speed and the operation of the hydraulic pump and of the fan can continue to be maintained at 100% or at 1200 r.p.m. A result of the operation of the hydraulic pump and of the fan at maximum operating powers and the setting of the speed of the diesel engine 1 to 1200 r.p.m. is an increase in the exhaust gas temperature. An operator of the mining machine or a CA 3034312 2019-02-20 - 9 - person who carries out the driving in accordance with the invention can monitor the degree of contamination of the exhaust gas purification device. If the degree of contamination reaches a specific critical level, the operator can end a work process such as an excavation process of the machine and / or can switch the machine to idling operation so that the method in accordance with the invention can be carried out. CA 3034312 2019-02-20

Claims

- 10 - CLAIMS 1. A method of operating a drive of a mining machine, comprising at least one diesel engine and at least one exhaust gas purification device, comprising the steps: .cndot. determining a coolant temperature of the at least one diesel engine; .cndot. determining a speed of the at least one diesel engine; .cndot. determining a contamination of an exhaust gas purification device by at least one of soot and non-combusted hydrocarbons; and .cndot. setting a new speed of the diesel engine greater than an idling speed thereof in dependence on the determined values.

2. A method in accordance with claim 1, wherein the new speed of the diesel engine is set to a predefined speed.

3. A method in accordance with claim 2, wherein the new speed is approximately 1200 r.p.m.

4. A method in accordance with any one of claims 1 to 3, wherein the new speed of the diesel engine is set when the coolant temperature is greater than a predefined temperature.

5. A method in accordance with claim 4, wherein the predefined temperature is 50°C.

6. A method in accordance with any one of claims 1 to 5, wherein the new speed of the diesel engine is set when the determined speed of the diesel engine is a predefined idling speed.

7. A method in accordance with claim 6, wherein the predefined idling speed is approximately 800 r.p.m.

8. A method in accordance with any one of claims 1 to 7, wherein the new speed of the diesel engine is set when the determined contamination exceeds a settable threshold value.

9. A method in accordance with any one of claims 1 to 8, wherein the determined contamination with at least one of soot and non-combusted hydrocarbons is displayed.

10. A method in accordance with any one of claims 1 to 9, wherein the setting of the new speed is ended when the determined contamination is close to or at 0%.

11. A method in accordance with any one of claims 1 to 10, wherein the setting of the new speed is ended when a user of the mining machine manually changes the speed of the diesel engine.

12. A method in accordance with any one of claims 1 to 11, wherein the determination of the contamination and / or the setting of the new speed takes place automatically or manually, with provision in particular being made that this is enforced by a manual actuation in a servicing phase of the mining machine.

13. A method in accordance with any one of claims 1 to 12, characterized in that the method further comprises the step: setting at least one hydraulic pump and / or at least one fan of the mining machine to full operating power.

14. A method in accordance with any one of claims 1 to 13, wherein the mining machine is one of a mining excavator, a mining loader, and a mining tipper.

15. A mining machine configured to be operated in accordance with the method in accordance with any one of claims 1 to 14.

16. A mining machine in accordance with claim 15, wherein the mining machine is one of a mining excavator, a mining loader, and a mining tipper.