Lubricants and / or coolants as well as aging processes

Abstract

The invention relates to a lubricant and / or coolant made from a synthetic base oil for an electric drive system for a motor vehicle, wherein the electric drive system includes an electric machine and a transmission device. The invention is characterized in that it comprises at least the following additives: - Cu as Cu oxide, Cu(I, II) oxide (20 mgl) I) - Fe as Fe oxide, Fe(II, III) oxide (450 mg / l) - Al as Al2O3 (30 mg / l) - Mg as MgO (100 mg / l) - sulfur-containing additive package. The invention further relates to a method for the thermal treatment of the lubricant and / or coolant according to the invention and a method for testing aging effects on electric drives.

Description

[0001] The invention relates to a lubricant and / or coolant. The invention also relates to a method for thermally treating the lubricant and / or coolant according to the invention and to a method for testing aging effects on electric drives.

[0002] Lubricants and coolants are subject to aging when used over extended periods. Oxidized oil or waste oil affects the functioning of electrical machines.

[0003] To test such effects of aging effects of the lubricant or coolant on the electrical machines, used oil is required. The problem here is that it is not possible to wait until used oil is available. It is therefore advantageous if the properties of the oil can be adapted to those of used oil. For this purpose, an oxidized oil or used oil can be simulated using treatment processes, for example.

[0004] DE 10 2019 210 207 A1 discloses a method for aging lubricants or lubricating oils. Furthermore, a device for carrying out the method is proposed, which can be designed, for example, as an oil aging unit. In a first method step, the lubricating oil is pre-aged in a manner close to the application, such as in test runs or series production. In a further step, laboratory aging takes place. Laboratory aging can simulate an artificial aging process, particularly involving thermal-oxidative stress. Laboratory aging can accelerate the entire aging process and reduce costs. This allows the service life of the lubricants and the intervals for oil changes to be determined in a shorter period of time. The disadvantage of this approach is that a test run is still required, which requires a certain amount of time.

[0005] The object of the present invention is to provide a lubricant and / or coolant, a method for thermally treating the lubricant and / or coolant according to the invention and a method for testing aging effects on electric drives, which overcome the aforementioned disadvantages.

[0006] According to the invention, this object is achieved by a lubricant and / or coolant having the features of claim 1, and in particular in the characterizing part of claim 1. Advantageous embodiments and further developments emerge from the dependent claims. Furthermore, a method for thermally treating the lubricant and / or coolant according to the invention and a method for testing aging effects on electric drives are described.

[0007] The core of the lubricant and / or coolant according to the invention comprises at least the following additives: - Cu as Cu oxide, in particular as Cu(I, II) oxide, with a concentration of 20 mg / l, - Fe as Fe oxide, in particular as Fe(II, III) oxide, with a concentration of 450 mg / l, - Al as Al2O3, with a concentration of 30 mg / l, - Mg as MgO, with a concentration of 100 mg / l, and - sulfur-containing additive package.

[0008] By adding additives, an aging process can be directly simulated, without the time and effort of conducting tests or series production. Immediately after adding the additives, an aged, and especially oxidized, oil can be produced that can be used directly for testing an electrical machine.

[0009] The lubricant and / or coolant is formed from a synthetic base oil for an electric drive system for a motor vehicle, wherein an electric machine and a transmission device are provided in the electric drive system.

[0010] A 95% Group 3 gear base oil is preferred. The American Petroleum Institute (API) defines Group 3 as "a base oil with at least 90% saturates and a maximum of 0.03% sulfur, as well as a viscosity index of at least 120." This group can therefore be described as technologically synthetic oils. They can also be referred to as hydrocracked synthetic oils. Such an oil can also be referred to as "synthetic oil." Such oils are specifically oils with the highest grade of petroleum base oils, which can be produced entirely by hydrocracking, hydroimmunization, and hydrosulfurization. This makes these oils particularly chemically pure.

[0011] According to a very advantageous further development of the idea, it can be provided that a 5% gear oil additive package is used as the additive package.

[0012] Gear oils, especially those for electric drivetrains, contain sulfur-containing additive components. Aging processes, particularly those caused by temperature, oxidation, and / or chemical reactions, decompose these components, forming short-chain or low-molecular-weight sulfur-containing compounds. These short-chain or low-molecular-weight sulfur-containing compounds can be, for example, sulfides, disulfides, hydrogen sulfide, sulfites, sulfonates, SO2, and the like, some of which are highly volatile or gaseous. In addition to the unpleasant odor of these compounds ("rotten eggs"), the risk of copper corrosion and the formation of copper-sulfide bridges increases.

[0013] The additives for the additive package may include friction modifiers, various antioxidants that inhibit oxidation at different stages, as well as foam inhibitors, pour point depressants, dispersants to keep the transmission clean, and / or viscosity improvers to ensure sufficient viscosity at high operating temperatures.

[0014] According to an advantageous embodiment, it can be provided that an aging process is simulated by the additives, wherein the lubricant and / or coolant can be used as waste oil.

[0015] The invention further relates to a method for the thermal treatment of the lubricant and / or coolant according to the invention.

[0016] It is proposed that artificial aging be carried out, wherein at least three different operating periods are simulated, wherein in particular a first operating period is shorter than a second operating period, and a second operating period is shorter than a third operating period.

[0017] In one embodiment, the oil can be cooled after a first step and after a second step, each of which simulates an operating period. A temperature transition between the steps can be achieved by a temperature sequence with a respective intermediate temperature of 70°C to 90°C, in particular 80°C, for cooling. For example, a temperature sequence of 80°C - 110°C - 80°C - 130°C - 80°C - 180°C can be achieved. A heating gradient can be, in particular, 1°C / min. Other temperature values ​​are also conceivable.

[0018] According to a very advantageous development of the idea, it can be provided that, in order to simulate the three operating times, a temperature treatment is carried out at 110 °C for a period of 90 minutes, in a second step a temperature treatment is carried out at 130 °C for a period of 8 minutes, and in a third step a temperature treatment is carried out at 180 °C for a period of 2 minutes.

[0019] The invention further relates to a method for testing aging effects on electric drives. It is proposed that a lubricant and / or coolant according to the invention be used to simulate the aged lubricant and / or coolant.

[0020] The same features and advantages apply to the processes as described for the lubricant and / or coolant.

[0021] To carry out the process, an apparatus such as, in particular, a container, preferably a cylindrical glass vessel without a lid, can be used. This can be designed with or without insulation on the outside. Heating elements can be provided inside. Advantageously, however, no direct heating element or direct heating plate is provided. A uniform temperature can be ensured via an intermediate medium, such as, in particular, a silicone oil bath, preferably with a stirrer. For example, a propeller-shaped stirrer can be used for uniform stirring. Likewise, constant temperature monitoring can be achieved via a temperature sensor, in particular via at least one thermal measuring point in the medium.

[0022] The additives Cu, Fe, Al, and Mg can be added manually. The oxides are preferably in powder form when added.

[0023] Further advantageous embodiments of the lubricant and / or coolant according to the invention as well as of the method for thermally treating the lubricant and / or coolant according to the invention and of the method for testing aging effects on electric drives also emerge from the exemplary embodiment which is illustrated in more detail below with reference to the figure.

[0024] It shows: Fig. 1 a schematic representation of a process flow.

[0025] In the presentation of the Fig.1 schematically shows a possible embodiment of a process sequence. To simulate three operating times, a first step (1) can involve a temperature treatment at 110 °C for a period of 90 minutes. A subsequent second step (2) can involve a temperature treatment at 130 °C for a period of 8 minutes. Then, in a third step (3), a temperature treatment at 180 °C for a period of 2 minutes. The times can vary, so that the first step (1) can last, for example, 70 to 100 minutes, the second step (2) 6 to 10 minutes, and the third step (3) 1 to 3 minutes.

[0026] In one embodiment, the oil can be cooled after the first step (2) and / or after a second step (2). A temperature transition between the steps can be achieved by the temperature sequence with a respective intermediate temperature of 70°C to 90°C, in particular 80°C, for cooling. For example, a temperature sequence of 80°C - 110°C - 80°C - 130°C - 80°C - 180°C can be achieved. A heating gradient can be, in particular, 1°C / min. Other temperature values ​​are also conceivable. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 210 207 A1

[0004]

Claims

[1] Lubricant and / or coolant made from a synthetic base oil for an electric drive system for a motor vehicle, wherein an electric machine and a transmission device are provided in the electric drive system, characterized by that at least the following additives are included: - Cu as Cu oxide, - Fe as Fe oxide, - Al as Al2O3, - Mg as MgO - sulfur-containing additive package. [2] Lubricant and / or coolant according to claim 1, characterized by - a concentration of Cu oxide of approximately 20 mg / l, - a concentration of Fe oxide of approximately 450 mg / l, - a concentration of Al2O3 30 mg / l, and - a concentration of MgO 100 mg / l. [3] Lubricant and / or coolant according to claim 1 or 2, characterized by that a 95% Group 3 gear base oil is used as the base oil. [4] Lubricant and / or coolant according to one of the preceding claims, characterized by that a 5% gear oil additive package is used as the additive package. [5] Lubricant and / or coolant according to one of the preceding claims, characterized by that the additives simulate an aging process, whereby the lubricant and / or coolant can be used as waste oil. [6] Method for the thermal treatment of the lubricant and / or coolant according to one of claims 1 to 5, characterized by that artificial ageing is carried out, wherein at least three different operating periods are simulated, wherein a first operating period is shorter than a second operating period, and a second operating period is shorter than a third operating period. [7] Method according to claim 6 characterized bythat to simulate the three operating times, a temperature treatment is carried out at approximately 110 °C for a period of approximately 90 minutes, in a second step a temperature treatment is carried out at approximately 130 °C for a period of approximately 8 minutes, and in a third step a temperature treatment is carried out at approximately 180 °C for a period of approximately 2 minutes. [8] Methods for testing aging effects on electric drives, characterized by that the lubricant and / or coolant according to one of claims 1 to 5 is used to simulate the aged lubricant and / or coolant.

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