SE539892C2 - Lubrication system comprising an immobilized ion exchanger - Google Patents

Abstract

The present invention relates to a lubrication system (4) for an internal combustion engine (2), which lubrication system (4) comprises a plurality of components comprising an oil sump (20), an oil pump (22) arranged to feed the engine oil from the oil sump (20) further into the lubrication system (4). ), a cooling device (24) for cooling the engine oil, an oil filter device (26) for filtering the engine oil and a main oil line (40) intended to transport the engine oil in the lubrication system (4) to the moving parts of the system and the internal combustion engine (2). Each of the components comprises a contact surface intended to be in contact with the engine oil and at least one of the components comprises a surface-modified contact surface (200) which comprises an ion exchanger immobilized to the contact surface. The invention relates to an internal combustion engine comprising the lubrication system, a vehicle comprising the internal combustion engine and a method for removing hydrogen ions from engine oil intended for the lubrication system.

Description

The present invention relates to a lubrication system for an internal combustion engine, which system comprises an ion exchanger, an internal combustion engine comprising the lubrication system, a vehicle comprising the internal combustion engine and a method for removing hydrogen ions from engine oil intended for the lubrication system. BACKGROUND Today high demands are placed on small amount of substances that are as harmful to the environment as possible, at the same time as it is desirable to increase the time between service sessions. It is also desirable to service as many components as possible during one and the same service occasion. In order for an engine to meet this, high demands are placed on the oil used to lubricate and cool the engine. A well-functioning internal combustion engine consumes less fuel and releases a small amount of substances that are harmful to the environment. In order for an internal combustion engine to emit a small amount of pollutants, it is possible, for example, to increase the pressure and the temperature at which the combustion takes place. There are then even higher demands on the components included in the engine and the engine oil. Heavy-duty vehicles are subjected to great stress, as these must provide a very large force in order for the vehicle and associated load to be transported in the desired manner.

I \ / | engine oil is used as a lubricant in internal combustion engines. Contact with acid combustion gases acidifies the engine oil, which degrades and can become corrosive, which negatively affects both the tribological (lubricating) properties of the engine oil and the surface layer of the lubrication system.

To improve the properties of the engine oil, various additives are added to the engine oil. Among other things, acidity regulating (buffering) additives are added, but also viscosity regulating, antioxidant and anti-wear additives to be able to handle high pressures and temperatures. These additives are consumed over time and when the amount of additives in the engine oil has decreased to a certain level, the engine oil must be replaced. The consequence of the consumption of additives is, among other things, that the tribological properties of the engine oil deteriorate and in the worst case, the engine oil causes a corrosive wear on the components with which it comes into contact. Additives are important for the engine oil to function in a desirable way, but they also lead to increased levels of ash in the exhaust stream. Excessive levels of ash in the exhaust gases result in a higher load on exhaust gas cleaning components, such as the particulate filter. It is therefore of interest to keep the amount of additives in the oil as low as possible.

There is today a technology, COT (Clean Oil Technology), which continuously purifies the oil during operation. The system is mounted as a bypass channel and the oil passes both a fine-mesh particulate filter where very small solid pollutants are removed and an evaporator that separates liquid pollutants with lower vapor pressure than engine oil. However, this technique does not affect the increased acidity of the engine oil.

WO2013028122 describes a device for reducing the acidity of an engine oil. The device comprises a container which comprises a cation exchanger in the form of small particles. The cation exchanger ID document consists of particles of solid material, for example with a carbon / silicon-based basic structure, which can capture positive ions. The cation exchanger is monovalent and can thus bind free hydrogen ions from the engine oil. A certain amount of engine oil can flow through the container and the container is placed in the normal flow of the engine oil, but design changes in the oil system may be needed to make room with the container. The container has an additional disadvantage, in addition to being space-consuming, that it can increase the back pressure in the oil system. Furthermore, the container of this known type must be provided with, for example, a fine-mesh net in order to avoid contamination of the oil in the system with ion exchange particles. Thus, the efficiency of the ion exchanger may be lower than the theoretical efficiency.

SUMMARY OF THE INVENTION There is thus a need to effectively reduce the acidity of an engine oil (oil). At the same time, there is a need to reduce the acidity of engine oil with a system that requires as few design changes as possible. Furthermore, there is a need to avoid power losses, which can be caused by the back pressure in the normal flow of oil, as this can lead to increased fuel consumption. An object of the invention is thus to remedy the problems found in that prior art. In particular, the invention aims to provide an ion exchanger in a lubrication system with non-essential design changes while at the same time achieving an efficient ion exchange in the lubrication system without the engine efficiency being adversely affected.

A further object is to provide a lubrication system with an ion exchanger which can be regenerated in a simple manner.

These objects are achieved with a lubrication system as defined in claim 1 and a process for removing hydrogen ions from engine oil intended for the lubrication system as defined in claim 13.

According to the invention the above objects are achieved with a lubrication system for an internal combustion engine, which lubrication system comprises a plurality of components comprising an oil sump, an oil pump means for feeding the engine oil from the oil sump further into the lubrication system, a cooling device for cooling the engine oil, an oil filter device for filtering engine oil and in the lubrication system to the moving parts of the system and the internal combustion engine. Each of the components comprises a contact surface intended to be in contact with the engine oil. According to the invention, at least one of the decomponents comprises a surface-modified contact surface which comprises an ion exchanger immobilized to the contact surface.

The ion exchanger in the present application refers to materials which are molecules which in their structure can have one or more charges, positive or negative. The ion exchanger has at least one position in its molecular structure with an ionic bond. The ion exchanger may be, for example, an organic salt, an acid, a base, a biomolecule, but is not limited to these molecules.

The ion exchanger in the lubrication system is preferably a cation exchanger with at least one functional group that can capture positive hydrogen ions in the engine oil and emit positive ions of another impact to the engine oil. Preferably, the cation exchanger is monovalent. In this way, a maximum exchange of dehydration ions can take place in the oil, whereby the acidity of the oil can be reduced. The cation exchanger is preferably a weak cation exchanger, whereby a more efficient exchange of hydrogen ions in the oil can be achieved while other additives in the engine oil are minimally affected. The contact surface of the components can consist of metal, whereby a component which is easy to surface modify and which can withstand high temperatures and pressures can be obtained.

The contact surface can also consist of a polymeric material, for example plastic. Plastic is flexible and can be easily adapted to tight spaces and shaped to the desired shape. Plastics are also easy to surface modify.

According to one embodiment, the cooling device may comprise the surface-modified contact surface. The cooling device comprises a plurality of channels and the oil can circulate around the channels, whereby a large contact surface for the oil can be obtained in a small volume. Thus, an efficient ion exchange can be obtained.

According to another embodiment, the oil sump may comprise the surface-modified contact surface. The surface-modified contact surface can be provided in a simple manner on the contact surface of the oil sump. In addition, all oil in the system comes into contact with the oil sump and therefore all oil can come into contact with the ion exchanger and thus maximum cation exchange can take place.

According to a further embodiment, in which the main oil line is connected to bearings of single crankshaft via channels, the bearings are arranged so that they comprise the surface-modified contact surface. The bearings can be made of different materials and thereby the surface-modified contact surface can be obtained in a flexible manner.

Preferably, the lubrication system also comprises a regeneration arrangement coupled to the component comprising the surface-modified contact surface. The regeneration arrangement may comprise a by-pass valve for guiding the oil past the component or alternatively a valve arrangement both downstream and upstream of the component to prevent the flow of the oil through the component. A pump device can be connected to the component via a coupling device for feeding saline through the component, which saline regenerates the ion exchanger. The pump device can be external and can be arranged so that it connects to the system only when needed. Since the ion exchanger is located on the contact surface, no assembly of the component is required and thereby the ion exchanger can be easily regenerated, for example at service times, such as during oil changes. In one embodiment, the modified contact surface is included in the cooling device and the regeneration arrangement is connected to the cooling device.

In this way, the regeneration arrangement can be connected to the system in a simple manner. The invention also relates to an internal combustion engine which comprises the lubrication system as above.

Furthermore, the invention also relates to a vehicle which comprises the internal combustion engine.

The invention also relates to a process for removing hydrogen ions from an oil intended for a lubrication system. The method comprises the steps of i. Providing an engine oil intended for the lubrication system; ii. providing a lubrication system comprising a plurality of components comprising an oil sump, an oil pump arranged to feed the engine oil from the sump further into the lubrication system, a chiller for cooling the engine oil, an oil filter device for filtering the engine oil and a main oil line for transporting the engine oil to the lubrication system each of the decomponents comprising a contact surface intended to be in contact with the engine oil; iii. providing a surface-modified contact surface of at least one of the components comprising a monovalent cation exchanger immobilized to the contact surface; iv. passing the engine oil through at least one of the components comprising the surface-modified contact surface, whereby positive hydrogen ions of the engine oil are exchanged for positive ions of a different kind, thereby reducing the acidity of the engine oil.

With the present invention it is possible to achieve efficient ion exchange of single engine oil of an internal combustion engine, for example in a vehicle such as a truck or bus. The surface-modified contact surface allows an efficient interaction with the oil in the system and thereby an efficient ion exchange is obtained at the same time as the need for design changes in the ice lubrication system can be significantly reduced or even eliminated. With the aid of the present invention, the impact on the oil flow is minimized and thereby power losses can be minimized and the risk of increased fuel consumption can be reduced. The ion exchange prolongs the life of the engine oil by removing the acidifying substances, whereby longer service intervals become possible.

Additional advantages and objects of the invention are described below in the detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, as an example, preferred embodiments of the invention are described with reference to the accompanying drawings, in which: Fig. 1 shows a schematic side view of a vehicle, which includes an internal combustion engine lubrication system according to the present invention; a circuit diagram of a lubrication system according to the present invention, Fig. 3 shows a schematic side view of an internal combustion engine comprising a lubrication system according to an embodiment of the present invention, Fig. 4 shows a side view of an oil sump Fig. 5 shows a perspective view of an oil cooler, Fig. 6 shows a schematic drawing of the steps for immobilizing an ion exchanger to a surface.

DETAILED DESCRIPTION OF THE INVENTION The invention is described below with reference to the lubrication system and method generally described above. The lubrication system according to the invention is intended for an internal combustion engine which can be included in a vehicle.

Fig. 1 shows a schematic side view of an example vehicle 1, which vehicle comprises a lubrication system 4 for an internal combustion engine 2 with an oil sump 20 in direct contact with the internal combustion engine 2. The internal combustion engine 2 is connected to a gearbox 6, which is connected to the vehicle 1's drive wheel 8 via a transmission. The vehicle also includes a chassis 10.

A Lubrication System is used in internal combustion engines to lubricate moving parts of the system and the internal combustion engine using engine oil, which is also referred to as "oil" in this application, and which includes suitable additives for this purpose. The lubrication system comprises a plurality of components: at least one oil sump for storing engine oil, a single oil pump arranged to feed the engine oil from the sump further into the lubrication system, an engine oil cooling device, an engine oil filter filter and a main oil line for conveying engine oil to the engine oil parts.

The oil sump can be arranged in direct connection with the engine block of the internal combustion engine. The local oil sump is arranged in direct connection with the engine block of the internal combustion engine, the engine oil can then be fed from and returned to the oil sump from the moving parts of the engine in a simple manner.

The engine oil is fed further from the oil sump by means of an oil pump, which can be, for example, a peristaltic pump. The peristaltic pump generates a pump flow which fluctuates over time, the pressure delivered by the pump varying but sufficient for lubrication of the moving parts in the system and in the internal combustion engine.

A cooling device for the engine oil can be arranged downstream of the oil pump and a cold start valve which is used in cold start to lead the oil back to the oil sump before the operating temperature is reached. The cooling device comprises lines which enable the cooling by means of air or by the cooling device being connected to a cooling system, for example to the engine cooling system and when the oil circulates in the cooling device it is cooled down.

During normal operation, the oil is fed from the cooling device to an oil filter device which is arranged downstream of the cooling device. The oil filter device cleans the oil from particles, such as soot, with the help of a filter element. Preferably, the filter element is provided with a by-pass valve, the purpose of which is to control the amount of oil passing through the filter. In this way, a small amount of oil can be fed through the filter element, for example if the filter becomes too clogged before replacement / cleaning without resulting in too high a back pressure in the lubrication system.

Downstream of the oil filter device, an oil pressure transducer can be provided to regulate the pressure in the oil. The cooled oil can then be passed on to, for example, piston cooling. The oil can also be led from the oil filter directly via the main oil line to the other moving parts of the engine or to other components of the lubrication system such as valve train, compressor, high pressure pump, etc.

Fig. 2 shows a circuit diagram of an exemplary lubrication system 4 for an internal combustion engine 2 according to the present invention. The oil system 4 comprises an oil sump 20, an oil pump 22, a cooling device 24 and an oil filter device 26. The oil sump comprises engine oil 21. The oil pump 22 is connected to the lubrication system main line 40, which transports oil through the lubrication system 4 to the moving parts of the internal combustion engine 2. The oil pump 22 pumps oil from the oil sump 20 through the downstream cooling device 24 and the oil filter device 26 and further to the moving parts 28, for example a crankshaft (not shown) and other users, such as valve train, compressor, high pressure pump. The oil pump 22 may be a peristaltic pump and may be driven, for example, by motor transmission or by an electric motor. The oil filter device 26 includes a filter element 32 through which the oil from the oil sump 20 is filtered. A by-pass valve 36 is provided in connection with the oil filter device 26 to direct the oil past the oil filter device 26 if necessary, for example if the amount of oil passing through the through-filter device 26 must be regulated. The bypass valve 36 may be, for example, an electrically controllable valve 36 and it is arranged in a bypass line 38 to control the oil flow.

In the example system 4 in Fig. 2 it is further shown that downstream of the oil pump 22 a cold start valve 42 can be arranged to direct the oil back to the oil sump 20 via a branch line 52 before the operating temperature has been reached.

Downstream of the cooling device 24, a pressure relief valve 44 can be arranged via a branch line 53 to return a part of the oil to the oil sump 20 via a return line 54 if the pressure in the ice system 4 increases. Alternatively, the oil may be passed to an oil purification centrifuge 46 via a branch line 55, which purifies the oil from particles and then returns the oil to the oil sump 20 via a return line 56.

During normal operation, the oil is fed from the cooling device 24 to the oil filter device 26 which is arranged downstream of the cooling device 24. The oil filter device 26 purifies the oil from particles, e.g. soot. Preferably, the oil filter device 26 is provided with a by-pass valve 36 as described above. Downstream of the oil filter device 26, an oil pressure transducer 48 may be provided to control the pressure in the oil. The cooled and filtered oil can then be passed on via a branch line 58 to a piston cooling device 60, which cools down and lubricates the pistons. The piston cooling device 60 is activated when the oil pressure becomes sufficiently high during normal operation and the valve 68 upstream piston cooling device 60 is opened. This means that in normal operation the oil always goes to the piston cooling device 60 and the valve 68 is open. If the oil pressure becomes too high, activate the restrictor 83 which lets the oil through and returns the oil to the oil sump 20. The oil can be returned from the piston cooling device 60 back to the oil sump 20 via a return line 59.

The oil can be led from the oil filter device 26 also directly via main oil line 40 to the other moving parts 28 of the engine 2 such as crankshaft, valve train, compressor, high pressure pump, etc. The oil from these components 28 can be returned to the oil sump via return lines 62 and 64.

The lubrication system in Fig. 2 further comprises a crankcase gas purifier 70 for the purpose of purifying the crankcase gas which is an oily gas. Some of the oil from the main line 40 can be led to the purifier via a branch line 51. The purifier can function, for example, so that it separates heavy particles and small oil droplets by centrifugation from the gas. The gas is discharged from the purifier and the oil is returned to the oil sump 20 through a line 72.

The lubrication system of Fig. 2 also includes a number of restrictors 81, 82, and 83. For example, the gravel restrictor 81, which is located downstream of the oil pump 22, for the purpose of providing resistance to the oil flow to improve the operation of the oil pump 22. The rectifiers 81, 82 and 83 are intended to prevent excessive overpressure in the system. When pressure increases in the lubrication system to an elevated level, the restrictors 81, 82 and 83 act as open valves which let the oil through and return the oil to the oil sump 20.

Fig. 3 shows a schematic drawing of an internal combustion engine 2 which comprises a lubrication system according to the present invention, for example the system in Fig. 2. The internal combustion engine 2 comprises an engine block 80. The main oil line 40 is arranged, for example drilled, through the length of the whole engine block 80. to the moving parts of the engine, such as bearings on the crankshaft (not shown). The oil pump 22 is connected to the main line 40 of the lubrication system, which transports oil through the lubrication system 4 to the moving parts of the internal combustion engine 2.

The oil pump 22 pumps oil from the oil sump 20 through the cooling device 24 arranged downstream of the oil pump 22 and the oil filter device 26. The cooling device 24 may be, for example, air-cooled or it may be connected to the engine cooler 71.

Preferably, the lubricating system component, the contact surface of which is surface modified by immobilizing an ion exchanger to the contact surface, is selected from the lubricating system components comprising an oil sump, a cooling device, an oil filter device, a main oil line and bearings crankshaft coupled to the main line, and one or more .

In the exemplary embodiment shown in Fig. 2 and Fig. 3, the oil sump 20 comprises the surface-modified contact surface 200 which comprises the surface-immobilized ion exchanger according to the invention.

Fig. 4 shows an oil sump 20 in more detail in section in the longitudinal direction of the oil sump. The oil sump 20 comprises the surface-modified contact surface 200 which comprises the ion-exchanged ion exchanger according to the invention.

The contact surface is the surface that is in contact with the oil. If the contact surface is arranged in the oil sump, the contact surface covers at least the area below the oil level and preferably below the maximum oil level.

Fig. 5 shows a perspective view of a cooling device 24, which comprises a plurality of channels 240. Cooling devices are often made of aluminum and aluminum is a metal that is easily canned modified. In this embodiment, the top surface 260 and the channels 240 include the surface-modified contact surface 200 which includes the surface-immobilized ion exchanger of the invention.

Ion exchangers As previously described, ion exchangers or ion exchange materials refer to molecules that have the ability to bind positive or negative ions (cation and anion exchangers, respectively). Encation exchangers can capture positive ions of one kind while emitting positive ions of another kind. Similarly, an anion exchanger captures negative ions of one kind while emitting negative ions of another kind. The ions that are captured / released from an ion exchanger are called counterions. In the present invention, it is an object of the ion exchanger or ion exchange material to reduce the acidity of the oil. Therefore, the ion exchanger must interact with hydrogen ions in the oil, but it is important that the ion exchanger interacts minimally with additives in the oil so as not to inactivate beneficial additives in the oil. This in turn could lead to deterioration of oil functional and tribological properties. In order to minimize the risk of additives being adsorbed on the ion exchanger, it is therefore preferred that the ion exchanger is a monovalent cation exchanger, the purpose of which is to capture hydrogen ions as much as possible. The monovalent cation exchanger can exchange hydrogen ions in the engine oil for other, non-acidifying, ionic species. Below are two examples of what a cation exchanger can look like.

Na + R + J \ j \ 0- R is the molecule to which the ion exchanger is bound and can be any matrix that functions for an ion exchanger. An example of a matrix is polystyrene. The motion in these two cases is Na +.

The monovalent cation exchanger counterions are mainly monovalent. The cation exchanger's counterion can be, for example, alkali metals. The cation exchanger's counterions can, for example, be selected from Na * and K +, which are often used today in cation exchangers. Examples of functional groups of an ion exchanger are, for example, COO ", SO3", AsO3 ', C6H4O', HPOZ ", S", SeO3 ', but other functional groups are also possible.

Ion exchangers come in two forms, charged and uncharged. Charged cation exchangers are, for example, [COO] ', [SO3]', and uncharged cation exchangers have the counter ion bound via ionic bond to them, eg [COO] Na, [SO3] Na. 12 By contact with acidic combustion gases, the engine oil is acidified, ie. the content of free hydrogen ions in the engine oil increases. A cation exchanger has the ability to bind these hydrogen ions, which leads to a reduction in the acidity of the engine oil and an increased base number.

The ion exchanger of the present invention may be a strong or weak cation exchanger. The pKa value is the equilibrium constant which for aqueous solutions describes at which pH there is an equilibrium between the protonated, ie uncharged, shape and deprotonated, ie charged, form of the ion exchanger. Examples of the deprotonated form of cation exchangers are COO ", SO3" and HPOZ ' is COOH, SOgH and HZPOZ. This means that weak cation exchangers lose their charge at low pH while strong cation exchangers retain their charge. Strong cation exchangers have a pKa below 0, while weak cation exchangers have a pKa between 0 and 7.

In the present invention, the cation exchanger is preferably a weak cation exchanger, which can give a higher yield of hydrogen ions in an engine oil than a strong ion exchanger. Weak and strong ion exchangers and their respective exchange of hydrogen ions in an engine oil have been studied, among others, in a thesis "Ceco, I \ / lima; I \ / | aster's Thesis, 28 June 2013: Evaluation and optimization of | H cation exchange materials for life-span optimization of engine oi It is also important that the ion exchanger can withstand high temperatures and pressures.An example of a weak ion exchanger re is acetic acid: ätt to f; H ~ § ~ Q: ä Qcc Acetic acid has a pKa of about 4.7- 4.8 Other weak ion exchangers are also possible to use in the present invention.

As described above, the lubrication system of an internal combustion engine comprises a plurality of components whose purpose may be, for example, to store, transport or treat the oil in the lubrication system, and each of these components comprises a structural contact surface intended to be in contact with the engine oil. Instead of arranging a separate container comprising an ion exchanger in the form of particles in the lubrication system, according to the invention at least one of the contact surfaces of the components of the lubrication system is surface modified by bonding an ion exchanger to the surface.

The contact surface means a surface which is part of the normal construction of the component and the contact surface is intended to be in contact with the oil in the lubrication system. For example, the contact surface may be all or part of the inner surface of the oil sump which is in contact with the oil when the oil is stored in the oil sump.

By surface modification is meant that the properties of the contact surface are changed by a chemical reaction or treatment, for example by binding of molecules to the surface. According to the present invention, the binding of the ion exchanger is performed by immobilizing, i.e. binding, a cation exchanger to the contact surface. As described above, if the acidity of the oil is to be reduced, a monovalent cation exchanger with at least one functional group is used which can trap hydrogen ions in the oil and emit positive ions of a different kind to the oil. Immobilization can be performed using conventional methods, which are well known, for example, in internal biotechnology. Through the immobilization, different molecules can be bound or coupled to a support or surface. I / O molecules can be ion exchangers, eg monovalent cation exchangers. The solid support may be, for example, metal or polymeric material, such as plastic.

According to the present invention, the immobilization can be performed in many different ways and the coupling technique itself is not essential to the invention. The purpose of the immobilization is that the ion exchange, i.e. the molecule with the functional groups, binds to the contact surface of one component. The molecules can, for example, covalently bind to the contact surface. The bond can be either directly or indirectly via one or more linker molecules, ie intermediate molecules between the ion exchanger and the contact surface.

Essentially, the method of immobilizing the deion exchanger to the contact surface steps comprises first activating groups in the contact surface, i.e. the substrate, to enable adsorption of the deion exchanger to the surface. Activation can be done using various methods, for example using PVD (Physical Vapor Deposition) coating technology on metal surfaces or using flaming on polymer surfaces. Thereafter, the activated metal surface can react with the exchange exchanger and / or with linker molecules. The ion exchanger and / or the linker molecules can be applied simultaneously or one at a time by applying the linker molecules first. In the next step 14, the activated groups on the surface are inactivated to prevent immobilization of other molecules other than the ion exchanger on the contact surface. In the last step, the contact surface is dried and washed and the contact surface is then ready for use. Examples of different coupling methods that show how molecules can be immobilized on different polymeric surfaces or metal surfaces are described in more detail in the book “Buddy D.Ratner et al .; Biomedical engineering; Elsevier, pp. 330-334 ", which is also published on the internet via the Google Books service.

Fig. 6 schematically shows the principle of immobilizing an ion exchanger to a metal or polymer surface. In step A) it is shown that the contact surface 200 'in a component 400 is activated by, for example, ionizing radiation, such as an oxygen plasma 90', provided from a dedicated device 90. In step B) it is shown that the contact surface 200 'has been activated and contains groups 201 which can react with an ion exchanger 300 directly or vial linker molecules (not shown). In step C) it is shown that the activated groups 201 have reacted with the ion exchanger 300, which has thereby been immobilized or bound to the contact surface and thereby formed a surface-modified contact surface 200 which comprises an ion-exchanged ion exchanger 300.

Further examples of how molecules can be immobilized on polymeric surfaces are described in "Leute, A. et al .; Static SIMS Investigation of Immobilized I \ / Iolecules on Polymer Surfaces; AdvancedI \ / Iaterials, 1994, 6, No. 10, p. 775 -780 "and" Tabata, Y. et al .; Immobilization of collagen onto polymer surfaces having hydroxyl groups; Biomaterials 1986, Vol 7 I \ / Iay 1986; pp. 234-238 ”.

Further examples of coupling methods which show in more detail how organic molecules can be immobilized on different metal surfaces are described, for example, in "Touahir, L., et al .; I \ / Iolecular monolayers on silicon substrates for biosensors; et al. Towards osseointegration of bioinert ceramics: Can agents be immolized onalumina substrates using self-assembled monolayer technique ?; vvwvvsciencedirectxom; Journal of the European Ceramic Society 22 (2013) 2705-2713 ", as well as" Nanci et al .; Chemicalmodification of titanium surfaces for covalent attachment of biological molecules; 1998 John Wiley & Sons, Inc.J Biomed I \ / later Res., 40, 324-335, 1998 ".

Regeneration of ion exchangers Ion exchangers are regenerable and can thus be used again and again, after regeneration.

Regeneration means that the ion exchanger's ability to exchange desired ions is restored.

According to the present invention, the ion exchanger can be regenerated by providing a regeneration arrangement (not shown in the drawings) coupled to a component comprising the surface-modified contact surface. The arrangement may include a bypass valve for guiding the oil past the component. The advantage is then that regeneration can be done without shutting down the lubrication system. Another alternative is to provide a valve arrangement both downstream and upstream of the component to prevent the flow of oil through the component. In this way, a simple construction can be obtained and the regeneration can be carried out, for example, at service times. In both cases, a pump device is provided, which can be connected to the component via a single-coupling device, to feed a saline solution through the component. The saline solution can then regenerate the ion exchanger by means of its flow through the component until the active groups of the ion exchanger are reactivated. The component is then drained from the saline solution and filled with new oil. The valves are switched again so that the oil in the lubrication system can flow through the component. For example, the saline solution may be a basic solution with a high salinity. A typical such solution is 8-10. By arranging the value of the pH of a saline solution in the regeneration arrangement to flow through the component with the surface-modified contact surface, the regeneration becomes efficient.

The invention has been described above as applied to a lubrication system for an internal combustion engine in a vehicle. However, the present invention is not limited to the embodiments described above but can be used in other applications where similar problems and conditions exist. The invention can be used, for example, in engines intended for pre-marinade or industrial use where, in an analogous manner, there may be a risk that the oil becomes acidic and there is no room or possibility for design changes. The invention is thus limited only to what is defined by the appended claims.

Claims (1)

A lubrication system (4) for an internal combustion engine (2), which lubrication system (4) comprises a plurality of components comprising an oil sump (20), an oil pump (22) arranged to feed the engine oil from the oil sump (20) further into the lubrication system (4), a cooling engine (24) for cooling the engine oil, an oil filter device (26) for filtering the engine oil and a main oil line (40) intended to transport the engine oil in the lubrication system (4) to the moving parts of the system and the internal combustion engine (2), each of the decomponents comprising a contact surface intended to be in contact with the engine oil characterized in that at least one of the components comprises a surface-modified contact surface (200) comprising an ion exchanger immobilized to the contact surface. Lubrication system according to claim 1, characterized by the deion exchanger is a monovalent cation exchanger with at least one functional group which can capture positive hydrogen ions in the engine oil and emit positive ions of another kind to the engine oil. Lubrication system according to claim 2, characterized in that the cation exchanger is a weak cation exchanger. Lubrication system according to one of the preceding claims 1-3, characterized in that the contact surface consists of metal. Lubrication system according to one of the preceding claims 1-3, characterized in that the contact surface consists of a polymeric material, for example plastic. Lubrication system according to one of the preceding claims, characterized in that the cooling device (24) comprises the surface-modified contact surface. Lubrication system according to one of the preceding claims, characterized in that the oil sump (20) comprises the surface-modified contact surface. Lubrication system according to one of the preceding claims, characterized by the main oil line (40) is connected to bearings of a crankshaft via channels, the bearings comprising the surface-modified contact surface. Lubrication system according to any one of the preceding claims, characterized in that the system comprises a regeneration arrangement coupled to the component comprising the surface-modified contact surface (200), which regeneration arrangement comprises a by-pass valve for guiding the oil past the component or alternatively a valve arrangement both downstream and upstream of the component to prevent the flow of oil through the component, and a pumping device, which can be connected to the component via a coupling device for feeding a saline solution through the component to regenerate the ion exchanger. Lubrication system according to claim 9, characterized in that the modified contact surface (200) is included in the cooling device (24) and the regeneration arrangement is connected to the cooling device. Internal combustion engine (2), characterized in that it comprises the lubrication system (4) according to any one of claims 1-10. Vehicle (1), characterized in that it comprises the internal combustion engine (2) according to claim 11. Method of removing wet ions from an engine oil intended for a lubrication system (4) for an internal combustion engine (2), characterized in that the method comprises the steps of i. a motor oil; ii. providing a lubrication system (4) comprising a plurality of components comprising an oil sump (20), an oil pump (22) arranged to feed the engine oil from the oil sump further into the lubrication system, a cooling device (24) for cooling the engine oil, an oil filter (26) for filtering the engine oil and a main oil line (40) for transporting the engine oil in the lubricating system to the moving parts of the system and the internal combustion engine (2), each of the decomponents comprising a contact surface intended to be in contact with the engine oil; iii. providing a surface-modified contact surface (200) comprising a single-care cation exchanger immobilized to the contact surface of at least one of the decomponents; passing the engine oil through at least one of the components comprising the surface-modified contact surface, whereby positive wet ions of the engine oil are exchanged for positive ions of a different kind, thereby reducing the acidity of the engine oil.