EP2959123B1 - Heat-insulated system for lubricating rotating and oscillating components of a motor vehicle - Google Patents

Description

The invention relates to a heat-insulated lubricating system for lubricating rotating or oscillating components, in particular a lubrication system for a motor vehicle, which can be used for the lubrication of moving parts of an internal combustion engine such as gasoline or diesel engine and / or lubrication of a transmission. The lubrication system can be used for example in a conventionally driven vehicle or in a hybrid or electric vehicle, but also in stationary systems such as power generators, work machines, etc.

STATE OF THE ART

Lubricating systems for moving parts of a drive, in particular an engine or mechanical transmission are well known. They serve to reduce friction between moving parts and to improve smooth running of the moving parts against each other. This reduces abrasion, reduces thermal heating of the parts and thus increases the service life. A stiffness of moving parts also requires an increased drive energy that must be used in unproductive manner to overcome the stiffness and brings an increased fuel or electricity consumption, so that on the one hand increases exhaust emissions, increased operating costs and, for example, reduced a range of a motor vehicle becomes. In particular, a reduction in the exhaust gas load and a low energy consumption are not only technically desirable properties of an engine, but internationally indispensable prerequisites, to comply with various government standards and limits. Not least, an inefficient lubrication management of a drive can lead to increased tax and duty load of the operator.

In a cold start phase, in particular at low temperatures such as 0 ° C or extreme temperatures such as -15 ° C or less, there is the problem that an inserted lubricating medium, in particular lubricating oil, has a high viscosity and thus reduced lubricating property. Thus, in a combustion engine, the fuel consumption during a cold NEDC test (starting temperature about 24 C) about 10 to 15% higher than the same test with an engine oil temperature in a hot state of about 90 ° C, the so-called NEDC -Heißtest. This is partly because the lubricating oil has a higher toughness at lower temperatures. At the same time, a large part of the energy supplied is discharged unused as exhaust gas enthalpy. This is a total of about 30 to 40% of the energy of the fuel supplied.

One way to reduce friction losses is to use high quality lubricating oils with reduced viscosity at low temperatures, another option is to provide targeted rapid heating of the lubricant in the cold start phase.

To accelerate heating during a cold start phase, proposals are for the use of heat exchangers, which provide increased heat input into the lubrication system, especially during a cold start phase. It is known from various publications that a heating of the engine oil with the aid of an exhaust gas / oil heat exchanger can significantly reduce fuel consumption and exhaust emissions. In this case, the warm-up phase of the engine is accelerated by the use of exhaust gas heat exchangers, which heat the engine oil in a complicated manner and reduce the oil pressure. However, there is the problem of protecting the engine, in particular the engine oil, from overheating during this heating. Therefore, additional high performance oil coolers are used. The known solutions are However, technically and structurally complex and error-prone and lead only to a relatively small reduction in fuel consumption, so that for economic reasons, the practical implementation is usually not realized.

Exemplary here on the DE 10 2009 013 943 A and the PCT / EP2010 / 053643 referenced, each proposing a Ölbypassleitung, is at least partially decoupled from a large amount of lubricating oil in a start phase, a reduced amount of lubricating oil for oil lubrication directed by rapidly heating areas of an internal combustion engine or a transmission.

From the JP 2001 323808 A an oil lubrication system can be removed, in which from an oil suction pipe, which is arranged in an oil sump, oil can be introduced by means of an oil pump in a lubrication system, said oil is heated by means of an oil bypass line and a heat exchanger through an exhaust system. The heated oil can be stored in a thermally insulated intermediate tank and fed back into the lubrication system by means of a supply line directly under the suction bell of the oil sump.

Further suggested solutions are in the conference papers: Will, F .: "A novel exhaust heat recovery system for reducing fuel consumption", F2010A073, FISITA conference Budapest, Hungary 2010 , such as Will, F., Boretti, A., "A New Method to Warm Up Lubricating Oil to Improve Fuel Economy," SAE 2011-01-0318, 2011 (Society of Automotive Engineers ) discussed.

In the DE 10 2011 005 496 A1 For example, a lubrication system for an internal combustion engine is described that includes an oil circuit, a radiator, and a heat accumulator located upstream of the engine for heating the oil. The heat accumulator is connected in parallel with the radiator, whereby a valve can switch the oil circuit between radiator and heat accumulator. It will pointed to an external insulation of oil lines to the heat storage, if the heat storage is located further away from the engine. External insulation is subsequently easy to install and greatly alters mechanical dimensions and appearance of the insulated areas as well as their durability and mechanical resistance. Furthermore, an external insulation usually has a low fire resistance and thus represents a fire safety risk, and may be damaged, for example, by marten bite. Another disadvantage of external insulation is the resulting increase in surface area resulting in increased heat loss. Furthermore, the total weight is increased by external insulation. In the case of an inner insulation of a metal housing, on the other hand, the weight is reduced since a part of the heavy metal housing is replaced by a lighter insulating layer, in particular plastic. At no point in this document is pointed to an inner insulation of the oil line, especially not in a metal housing. With a housing made of an insulating material such as plastic, no comparable structural strength, rigidity or toughness can be achieved as in a metal housing, or other disadvantages such as high costs, for example when using ceramic are the result.

From the DE 10 2009 051 820 A1 is a heat storage of an oil lubrication system for storing heated gear oil known. By means of a spring-loaded cylinder in the heat storage gear oil from the transmission in the storage tank and vice versa are promoted, the transmission oil can be promoted by spring force in and out of the memory. The proposed heat accumulator with spring-loaded cylinder comprises a complex geometry and mechanical design and is correspondingly expensive. Due to the spring-loaded cylinder comes for a possible isolation of the storage enclosure only a volume-increasing outer insulation in question, which brings the aforementioned disadvantages. The application of the spring-loaded cylinder is limited to a passive transmission lubrication.

The DE 30 32 090 A1 also relates to a method for accelerated heating of lubricating oil in a warm-up phase of an internal combustion engine, wherein by a heat pipe or a heat exchanger lubricating oil to be heated faster. It is proposed that the oil pan have controlled thermal insulation, where the louvers or shutters can be opened or closed as needed to cool or isolate the oil pan from the ambient air.

Disadvantages of the upper proposals for reducing friction losses are, on the one hand, the high design complexity and the increased susceptibility to errors, and in particular the small reduction in friction losses compared with the effort, since the heated oil quickly cools again when it comes into contact with cooler components , such as the oil galleries in cylinder block and cylinder head as well as the housing (for example oil sump and crankcase) ..

Object of the following invention is to propose a lubrication system that overcomes the above-mentioned disadvantages of the prior art, provides a simple technical implementation and offers a significantly reduced friction, especially in the cold start phase.

DISCLOSURE OF THE INVENTION

The above object is achieved by a lubricating system according to the independent claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

According to the invention, the system for lubricating rotating or oscillating components comprises at least one oil suction pipe, which is arranged in an oil reservoir, an oil pump, a heat source and further connecting lines, which are integrated in a metal housing, in particular an oil gallery for distributing lubricating oil to the components to be lubricated such as crankshaft, camshaft, gear parts, etc. The oil reservoir can be an open and usually not isolated storage and can in its structural design of a Correspond to oil pan. It is proposed that at least one connection line within the oil gallery downstream of the heat source is insulated inwardly by an internal insulation, the thermal conductivity of the inner insulation being 5% or less than the thermal conductivity of the connection lines or the remaining oil gallery and preferably at least less than 1 W / (m K) and the heat source is switched off or at least reduced in its heat output when a first upper limit oil temperature is reached. The outer circumference of the connecting line can be at least twice as large as the inner circumference of the connecting lines, at least at one point.

In other words, it is proposed according to the invention that at least part of a connecting line behind an oil pump, i. in a pressurized connection line region of a lubricating system and preferably behind a heat source, such as a heat exchanger having insulation, in particular an inner insulation, which makes a thermal heat transfer from the lubricating oil to the metallic environment more difficult. This ensures that, after heating a pressurized volume of oil that in the supply of the points to be lubricated, especially the oil gallery only slightly absorbed his heat to the metallic environment, which has a high thermal conductivity value. Thus, a rapid heating of the oil, which is delivered via lubrication points directly to the points to be lubricated, can be achieved and thus a reduced friction, in particular during cold start can be effected.

So is indeed from the DE 10 2009 013 943 the use of an exhaust gas oil heat exchanger for a lubricating oil heating also described in combination with a cylinder head oil return line, which allows improved lubrication in the cold start phase and thus a saving in fuel consumption, but this requires a complex structural design of the engine and are not implemented in existing engine structures can. It has been found that the use of an exhaust gas heat exchanger is advantageous, especially in high-performance machines with relatively large oil galleries, where the surface-to-volume ratio is particularly small. In small internal combustion engines, in which a considerable proportion of the exhaust gas heat can be introduced into the lubrication system, a relatively large amount of heat is given off to the metallic environment due to the large ratio of surface to volume, so that no particularly advantageous rapid heating of the lubricating oil can be achieved. This can be illustrated by the following example comparison: Comparing an oil supply line with a diameter of 2 mm with a diameter of 1 mm, the volume with the formula V = I π D ^2/4 , with I, the length of the oil gallery and D as Diameter determined. The surface of the oil gallery is described as A = I π D, so that the ratio of surface to volume is A / V = 4 / D. For a diameter D = 2 mm results in a ratio of 2 / mm and for D = 1 mm, this is 4 / mm, which is twice as large as in the ratio for D = 2 mm. Thus, it can be seen that reducing the diameter D by 50% doubles the surface to volume ratio. As a result, there is a higher volume-specific heat transfer, so that at larger diameters, the temperature loss of the oil through the oil gallery is smaller, oil can be made thinner at the lubrication points. This effect is known from the structural design of engines with large combustion chambers, which have a higher specific efficiency over engines with small combustion chambers, since the different wall heat losses are significantly lower for larger combustion chambers because of the lower surface to volume ratios.

• Die Wärmeisolierung erhöht den thermischen Widerstand.
• Das Oberflächen- zu Volumenverhältnis wird verringert.
• Das Ölvolumen und damit auch die zu erwärmende Ölmenge in der Ölgalerie wird verringert.
• Der thermische Widerstand erhöht sich aufgrund des Kontaktwiderstands zwischen der Isolation und dem Motorblock oder den Zylinderköpfen.

Through the introduction of thermal insulation within an oil gallery, in particular at lubrication points of the functional structural environment for lubricating the components, but also the structural structural environment caused by the metal environment, crankshaft, connecting rod, camshaft, bearings, gears, housing areas, Engine block on the inner wall of a crankcase or transmission housing or the components moving against each other, several advantages can be achieved when transferring the heat in the cold engine block:

• The thermal insulation increases the thermal resistance.
• The surface to volume ratio is reduced.
• The oil volume and thus also the amount of oil to be heated in the oil gallery is reduced.
• The thermal resistance increases due to the contact resistance between the insulation and the engine block or cylinder heads.

mit r₀ = Außenradius, r_i = Innenradius, I = Länge der Ölgalerie und k = spezifische Materialkonstante. Es ergibt sich somit ein thermischer Widerstand von Ri = 0,1 k/W. Mit einem Oberflächen-Übergangswiderstand hc von 40 W/(m² K) ergibt sich ein Übergangswiderstand von Rc = 0.4K/W. Zur Verringerung des Oberflächen-Volumenverhältnisses des Volumens der Isolation gegenüber dem Originalvolumen ergibt sich Vi/V= (Di/D)² = 0.25 bzw. 25% mit Di=1mm und D=2mm.By reducing the surface-to-volume ratio, less heat is dissipated to the metallic environment. By way of example, this can be considered by considering an insulation line with a thermal conductivity of 1 W / m K in an oil gallery with a diameter of 20 mm and an inner diameter of 10 mm. The thermal contact resistance is considered when considering a heat transfer coefficient between the oil and cylinder block at h = 40, assuming that the oil is 20 ° C warmer than the engine block. This results in a thermal resistance R = 1 / (h A) = 1 / (hl π D) = 0.4 K / W. The thermal resistance is described by $$R_{\mathit{pipe}}=\frac{\ln \left({}^{r_{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">O</figure-callout>}}}{/}_{r_i}\right)}{2\mathit{\pi kl}}$$

with r ₀ = outer radius, r _i = inner radius, I = length of the oil gallery and k = specific material constant. This results in a thermal resistance of Ri = 0.1 k / W. With a surface contact resistance hc of 40 W / (m ² K) results in a contact resistance of Rc = 0.4K / W. To reduce the surface-to-volume ratio of the volume of insulation from that Original volume is Vi / V = (Di / D) ² = 0.25 or 25% with Di = 1mm and D = 2mm.

• Die Isolation den thermischen Übergangswiderstand um 25 % erhöht,
• Das Oberflächen- zu Volumenverhältnis um 50 % reduziert wird, was den thermischen Widerstand um weitere 100 % erhöht,
• Das Ölvolumen in der Ölgalerie um 75 % abgesenkt wurde,
• Der thermische Widerstand aufgrund des Kontaktwiderstandes sich nochmals um zusätzliche 100 % erhöht.

Thus it can be stated in the result that with the above mentioned values:

• The insulation increases the thermal contact resistance by 25%,
• The surface to volume ratio is reduced by 50%, which increases the thermal resistance by a further 100%,
• The oil volume in the oil gallery was lowered by 75%,
• The thermal resistance due to the contact resistance increases again by an additional 100%.

For this reason, the total thermal contact resistance is 3.3 times greater than without the proposed inner insulation. For this reason, improved heating can be achieved because the energy loss of the oil in the cold start phase is lowered and improved lubrication in the cold start phase is given.

In the publication of the Japanese Society of Automotive Engineers (JSAE 235-20125071) it is proposed to divide the oil in the oil reservoir into two sub-volumes for improved heating of oil in a cold start phase, during which only a portion of the oil in the oil reservoir is used for lubrication during a warm-up phase. If the same amount of heat is introduced into the reduced volume of oil, the oil can heat up twice as fast as if the amount of heat were added to the total amount of oil, although this has been found to be inaccurate, as described in the publication JSAE 235- It has been shown that dividing the oil reservoir into two partial volumes made it clearer for the outer colder oil volume that during a test the maximum temperature increased from 85 ° C to 45 ° C, ie around 40 ° C was lowered while, however in the internal volume of oil, the temperature could not be increased equally by 40 ° C from 85 ° C to 125 ° C. Since the oil volume of the inner chamber was lower than that of the outer chamber, it was expected that the temperature increase should be larger. This, too, has proved to be a fallacy, since the temperature inside could only be increased by a maximum of 5 ° C, resulting in a very small fuel saving of only 0.8%. As a cause, it was recognized that the heat of the inner oil volume was mainly dissipated by the heat transfer between the engine block and the crankshaft, the oil being thrown to the outer wall of the crankcase as soon as it reaches the crankshaft bearings. The housing temperature and the temperature of the engine block thus predominantly determine the oil temperature due to their large surfaces. For this reason, the oil temperature can not significantly exceed the coolant temperature and the temperature of the engine, at least not achieved at average cold start phases and thus only a small fuel economy. Improved insulation, however, overcomes these disadvantages, resulting in significantly reduced friction, significantly lower fuel consumption and lower exhaust emissions.

An internal insulation of a metal housing and a metal conduit also makes it possible to produce oil conduits and housings made of metal or permanent, but thermally conductive materials, and to maintain given external mechanical dimensions, since only an internal insulation is to be used, and external dimensions and structural details can be maintained and thus Rebuilding an existing aggregate design can be avoided. Internal insulation of oil pipes and housing parts makes existing engines and units more efficient without having to make design changes.

According to an advantageous embodiment of the invention, the housing of the lubrication system, in particular a crankcase or transmission housing, by a Be isolated inside insulation, wherein the thermal conductivity of the inner liner 5% or less than the thermal conductivity of a structural environment, in particular as the thermal conductivity of lubrication points, a housing, the components to be lubricated, a metal environment, and preferably at least less than 1 W / (m K) is. The structural environment describes a functional structural environment of the lubrication system, ie lubrication points where surfaces move against each other, as well as structural structural environments, ie the surrounding material such as metal housings, components, engine block etc.

According to a further advantageous development of the oil reservoir can be isolated by an inner insulation, wherein the thermal conductivity of the inner insulation is 5% or less than the thermal conductivity of the oil reservoir, and preferably at least less than 1 W / (m K). Alternatively or additionally, the oil reservoir may be made entirely or at least partially of an insulating material which has a thermal conductivity of preferably at most less than 1 W / (m K).

According to an advantageous embodiment of the invention, at least one of the components to be lubricated, rotating or oscillating can be insulated by at least one inner insulation and / or outer insulation, wherein the thermal conductivity of the outer insulation is 5% or less than the thermal conductivity of the rotating or oscillating components to be lubricated , and is preferably at least less than 1 W / (m K).

By insulating both the crankshaft housing and the oil sump from the inside and also at least portions of the rotating or oscillating components to be lubricated, the oil can only slightly lose heat to the metallic environment and is not so much cooled down, the oil in the cold start phase is heated by higher heat inputs, for example by a heat source, for example by an exhaust gas heat exchanger. Due to the isolation of the crankshaft, the thermal mass, which is available for the cooling of the oil, is reduced and due to the insulation of the inner Crankshaft housing, which can be considered very significant for the heat retention of the oil, an improved heating at low viscosity of the oil can be achieved.

According to an advantageous development, a highly insulated heat accumulator may in particular be provided with at least 5 mm thick heat storage insulation with a thermal conductivity of less than 0.01 W / (m K), in particular between an oil suction pipe and an oil pump or between an oil pump and a heat source, or between a heat source and a lubricating point, wherein preferably a temperature loss of oil at a temperature of 100 ° C to 80 ° C at 25 ° C ambient temperature in more than 6 hours. Preferably, the heat storage insulation can be designed as a vacuum insulation.

In order to achieve an improvement in the heat storage in the aforementioned heat storage, it may prove advantageous if the oil connection lines and / or an outer jacket of the heat accumulator consists of a heat-insulating material having a thermal conductivity of less than 20 W / (m K). For this purpose, advantageously a plastic insulation can be used. Furthermore, the outer jacket of the heat accumulator can be double-walled and in the intermediate space between the inner wall and outer wall of the outer jacket, an insulating layer of airgel can be arranged, which has a thermal conductivity of less than 0.04 W / (m K). Furthermore, the filled with airgel volume may have a negative pressure to the environment. As a result, the insulation is significantly improved and prevents heat loss or unwanted heat input.

In a further advantageous embodiment of the invention, the lubrication system may comprise a bypass valve, so that the heat accumulator is filled with oil at least 90.degree. C. when reaching a second upper oil limit temperature outside the heat accumulator and at a cold start the oil to be lubricated components under a predetermined first lower oil limit temperature of at most 50 ° C outside the heat storage, the stored oil in the heat storage can be delivered to the lubrication system.

The use of heat accumulators in a lubrication system has been known for several years. These are often used to heat the passenger compartment preferred and reduce exhaust gases, especially at cold start below 0 ° C, as it was already shown in the publication SAE 922244. The disadvantages of such heat accumulators are comparable to those of the aforementioned two-part oil sumps or oil reservoirs, the fuel saving being low, as investigations at ambient temperatures of 24 ° C. have shown. Also, the explanation of why such heat storage can make only a small contribution to reducing fuel consumption, are the same as in a two- or multi-part oil sump, since the introduced heat is released quickly in the cylinder heads and in the engine block in the cold start phase. However, the proposed heat accumulator can advantageously overcome this with the preceding embodiments, wherein excess heat in the heat accumulator can be discharged from a cooling system or through a radiator or through an oil cooler, and through the improved thermal insulation the heat directly lowers the oil viscosity and contributes to friction reduction and thus leads to a reduction in fuel consumption.

Attaching to the lubricating system with the heat storage can have in an advantageous development of the heat storage at least a separate chamber with a phase change material, in particular with a sugar alcohol, such as erythritol, threit or a paraffin or the like or a salt, preferably a hydrate, nitrate, hydroxide or chloride such as magnesium chloride hexahydrate or magnesium nitrate hexahydrate. The latent heat of fusion of the phase change material should be much greater than the heat that the heat storage due to the temperature difference of the first lower and first upper limit oil temperature can be. Here, in particular, the melting temperature of the phase change material should be lower than the first upper oil limit temperature, and preferably - if the melting temperature of the phase change material is greater than 100 ° C - the phase change material erythritol be with a melting temperature of about 120 ° C, so that in cold start a highest possible Temperature is present in the heat storage. Preferably, a sugar alcohol is used as the phase change material, and the melting temperature of the phase change material is provided above 100 ° C.

As already mentioned above, latent heat storage are already known from the prior art. They use in various embodiments salt that has a melting temperature of 60 ° C to 80 ° C, such as. Barium hydroxide or Sodium silicates, such salts are material aggressive and cause corrosion damage that can lead to leaks in the cooling system or in the lubrication system. For this reason, a series production of such latent heat storage has been set. Another disadvantage of the known latent heat storage with phase change material was that the melting temperature is typically between 60 ° C and 80 ° C, which is clearly too low for an optimum temperature for oil lubrication, which is preferably 120 ° C. Thus, the use of such latent storage with salt-based phase change material could not sustainably improved lubrication in the cold start area. Use of phase change material with phase change temperatures above 80 ° C, especially erythritol as latent heat storage medium, overcomes these problems because it has a melting temperature that is optimal for lubrication with engine oils.

Attaching to the lubrication system with the heat storage can be carried out cylindrically in an advantageous embodiment of the invention, the heat storage and comprise a free piston of heat-insulating material, which divides the heat storage in two chambers. This is when filling the Heat storage with oil above a first upper limit oil temperature of at least 90 ° C in the first chamber, an oil volume from the second chamber pushed back into the lubrication system and when emptying the oil from the first chamber in a cold start phase below a first lower limit oil temperature of at most 50 ° C in the lubrication system will fill the second chamber with oil. Thus, the oil level in the oil reservoir is only insignificantly influenced and the heat storage is required, as a heat source, in particular as a heater and as a heat sink, in particular cooling device usable. The oil limit temperature may be an oil temperature of lubricating oil somewhere in the lubricating oil circuit, advantageously directly at a junction of the heat accumulator or Ölauslassstelle where typically the highest expected oil temperatures occur, such as. Exit point from the engine block, etc. In the case of filling the heat accumulator is hot Oil of the oil circuit absorbed by the heat storage and emit cooler oil, the heat storage thus serves as a heat sink. In a cold start phase and when emptying the heat accumulator cooler oil is absorbed and released warmer, the heat storage serves as a heat source.

At a high load on the parts to be lubricated, the oil temperature increases, so that a cooling effect of stored in the insulated heat storage and low-temperature oil can be exploited. Thus, advantageously, the heat accumulator can be arranged to effect an emptying of oil from the first chamber for oil cooling, as soon as oil in the oil circuit exceeds a second upper oil limit temperature of at least 110 ° C. In this case, typically, an oil temperature of oil in the first chamber is lower than the second upper oil limit temperature, so that the oil flowing out of the heat accumulator is colder than the inflowing oil. This effectively achieves cooling of the oil and achieves optimum lubricity and viscosity, and prevents overheating in the oil circuit.

Another problem of heat accumulators is that during the cold start phase returning cooled oil mixes with the stored heated oil to establish a mixing temperature lower than the previous temperature in the heat storage before interchanging with the environment. Lowering the temperature reduces the lubricating property and thus the friction in the lubrication system. This problem can be solved in that a free piston is provided in the heat accumulator, wherein the heat accumulator preferably has a cylindrical shape, which divides the memory into two sub-chambers, which are interconnected by switching valves, so that the preheated oil does not settle with the can mix cold oil. By the free piston, the oil volume is kept constant, so that this does not adversely affect the pressure conditions and the oil volume in the lubrication circuit.

According to an advantageous development of the invention, the lubricating system, oil reservoir, structural environment and heat source can be comprised by an internal combustion engine, in particular by an internal combustion engine of a motor vehicle.

Alternatively or additionally to the above development, the lubrication system, oil reservoir and structural environment may be comprised of a transmission, in particular a motor vehicle transmission, and the heat source may be provided by an internal combustion engine and / or an electric battery and / or an inverter. An inverter can convert DC to AC and vice versa and is used to drive AC and AC drives through batteries and accumulators. Thus, a lubricating medium in a transmission or a power transmission mechanism may be heated by waste heat from an internal combustion engine, or, for example, when used in an electric or hybrid vehicle by a heating characteristic of a battery or an electrical consumer, which become warm when the energy is released or absorbed. It is also conceivable that a fuel cell, for example in the case of a hydrogen drive, a heat source for heating the lubrication system for the drive mechanism / transmission provides.

Electric vehicles and hybrid vehicles, which are powered by a combination of electric and internal combustion engine, are confronted with the problem that they on the one hand have no intrinsic heat source such as an internal combustion engine, and yet the lubricating property, especially at temperatures below 30 ° C significantly lower and thus Increased friction and increased energy consumption. For rapid heating of the lubricating oil waste heat can be used, which is generated for example by an inverter, a fuel cell or an electric battery, or waste heat of an electrical unit can be used to achieve an optimum lubrication temperature, especially for a transmission. For example, a refrigeration cycle may be provided which interconnects the transmission, inverter, and battery to more quickly heat the transmission or heat transmission oil through a coolant-oil heat exchanger and cool the inverter or fuel cell, thereby providing improved performance Efficiency, increased range and low consumption can be achieved.

According to an advantageous embodiment according to the above two embodiments of the invention, a heat storage engine oil and transmission oil in a structural unit, and in particular comprise at least one chamber for engine oil and a chamber for transmission oil.

By a combined heat storage for engine oil and transmission oil, which in particular includes separate chambers for both oil lubrication systems, a uniform tank volume can be provided, the memory has a single high-quality insulation and requires little space. Thus, for example, a high-quality insulated tank, which has a vacuum insulation or which is filled with a phase change material, are provided, in particular two chambers for the two separate lubrication systems having. By integration into a single unit, the total volume can be significantly reduced, especially in critical space problems, such as occur in a motor vehicle. In addition, component costs can be saved and high-quality insulation used throughout the assembly, resulting in significantly lower costs and minimized problems with the development of such lubrication systems.

According to a further advantageous refinement, in the case of an internal combustion engine, the heat source can comprise an exhaust gas heat exchanger, or the heat source, in particular in the case of application in a transmission, can comprise a coolant heat exchanger and / or an exhaust gas heat exchanger of an internal combustion engine. In the case of a combination of coolant heat exchanger and exhaust gas heat exchanger, the exhaust gas heat exchanger may be arranged downstream of the coolant heat exchanger. In the coolant circuit, a coolant valve may be arranged, which is closed when falling below a coolant limit temperature, in particular below an opening temperature of the cooling circuit thermostat for activating a main water cooler, in particular at most 10 ° C below the Kühlkreislaufthermostattemperatur and is opened when the coolant temperature limit is exceeded. In particular, below the opening temperature of the cooling circuit thermostat, the coolant valve can be opened, preferably below 5 ° C below the opening temperature of the Kühlkreislaufthermostattemperatur.

According to an advantageous embodiment of the invention, the transmission may be a manual transmission or an automatic transmission, which has no oil pump, wherein a coolant heat exchanger is arranged in the oil reservoir, so that the transmission oil is warmed up by the engine coolant. It is advantageous that the coolant heat exchanger is provided on the coolant side with a coolant valve, which falls below a coolant temperature limit, in particular below the opening temperature of a cooling circuit thermostat for activating the main water cooler, in particular 10 ° C. or more below the Kühlkreislaufthermostattemperatur, is closed and is opened when the coolant limit temperature is exceeded, in particular below the opening temperature of the Kühlkreislaufthermostats is opened, in particular below 5 ° C below the opening temperature of the Kühlkreislaufthermostattemperatur is opened.

A manual transmission, or an automatic transmission of a vehicle can significantly reduce fuel consumption through improved lubrication. Preferably, the oil for lubrication of the gearbox can be heated by a cooling circuit, in particular at high loads, the oil temperature can be heated quickly, or an elevated temperature can be cooled by a high load in the transmission through the cooling circuit. In addition, it is conceivable that the transmission oil and the coolant can be heated by an exhaust gas heat exchanger, as described for example in SAE 2011-01-1171. However, if a coolant heat exchanger is used directly for heating the transmission oil, this has the disadvantage that the coolant heats up more slowly due to its greater specific heat capacity than the transmission oil and thereby friction and heat losses of the engine are impaired, especially in the cold start phase, so that the fuel consumption is higher is than the benefits that can be achieved by the exchange of heat between the coolant circuit and transmission oil. For example, the SAE 2011-01-1171 investigation has shown that the coolant temperature rises more slowly than the lubricating oil temperature within an automatic transmission. To overcome this, it may be advantageous if, in addition to the improved isolation of the lubrication system, the heat exchange between coolant and transmission oil is interrupted when the coolant temperature is lower than the switching temperature of a cooling circuit thermostat, whereby an external water cooler is switched on, and if the coolant flow through the coolant transmission oil heat exchanger is opened only when the Kühlkreislaufthermostattemperatur is exceeded and thus the coolant is significantly heated, in particular only if a heat exchange From the coolant to the oil can take place, that is, when the temperature of the cooling circuit is only slightly below the temperature of the cooling circuit thermostat. This ensures that a heat transfer or heating of the lubricating oil by the cooling circuit takes place only when the cooling circuit has become correspondingly warm, or a cooling of the oil circuit takes place only when the vehicle has arrived in a warm-up phase.

According to a further advantageous development, in the case of a transmission lubrication system, the transmission can be a manual transmission and the oil pump function can be provided by the displacement effect of a gear pair, in particular a Getriebeendantriebs. In this case, advantageously, an oil pressure line can be arranged on the side on which the two tooth flanks move toward one another and an oil return line can be arranged on the side on which the two tooth flanks move away from one another.

Like automatic transmissions, manual transmissions are also significantly more efficient and lower consumption, if the oil temperature of the transmission is increased. However, typical gearboxes do not have a separate oil pump, such as those found in automatic transmissions, for example, so that the oil in a manual transmission can not be pumped through a heat exchanger and an effective lubrication circuit in manual transmissions is not present. On the one hand, additional electric oil pumps may be provided to provide oil circulation and, in particular, heat input through a heat source for transmission lubrication, but this requires extra space, additional cost, and consumes more electrical energy, part of the fuel reduction through the improved lubrication eating again. For this reason, according to the advantageous development, on the one hand, a lubricating circuit for a manual transmission can be proposed, in which a heat exchanger is connected to a cooling system, which is the Heated oil in the oil sump of the manual gearbox faster. In order to produce an oil pumping action, an oil suction pipe carrying oil to the external oil exchanger may be disposed in the vicinity of a transmission end gear, which gears may move toward each other and thereby generate a pressure that can be used for the oil pumping action. The return from the oil heat exchanger may be provided at an opposite end of the gearbox drive, where gears move away from each other, creating a vacuum and providing an oil suction action. As a result, an oil pump action for operating a lubrication circuit can be provided without any additional effort, whereby a lower consumption can be achieved by an external heat source and improved insulation of the lubrication system.

Blow-by gases are gases that can pass from the cylinder combustion chamber past the piston into the crankcase and that can not be released directly into the environment in order to comply with corresponding emission standards. These gases are usually returned to the engine supply, and not released into the environment, without first being cleaned by a catalyst. The most common use here corresponds to the so-called PCV, the positive crankcase ventilation. In this case, a crankshaft exhaust port is coupled to the air supply of the engine and a blow-by gas valve is provided, which connects the crankshaft housing with a fresh air supply, typically with an air filter. A disadvantage of this design is that fresh air penetrates into the crankcase and the fresh air in most cases is colder than the crankshaft temperature and consequently the crankshaft cools accordingly, so that the viscosity of the lubricating oil increases and especially in the cold start phase, a higher friction and thus an increased fuel consumption occurs.

According to an advantageous development, the heat source, a connecting line of the exhaust pipe of an internal combustion engine with a Crankcase or include an engine block, wherein the crankcase has no connecting line between the ambient air and crankcase, so that no cooling of the crankcase can be done by the ambient air through the crankcase thus flows more exhaust of the internal combustion engine. Thus, fresh air is prevented from entering the crankcase, which could lower an oil lubricating temperature.

In many modern internal combustion engines, in particular with turbocharging piston injection cooling devices are provided in which an oil cooling jet injects oil from the crankcase or through an opening of the oil line in the connecting rod to the underside of the cylinder piston at high pressure when high speeds or high load phases occur to coking the engine oil , which is located behind the piston ring to prevent. In many cases, the piston spray cooling is controlled in response to engine oil pressure, such that, for example, at low oil pressures, such as less than 2 bar, no oil leaks through the spray nozzles and the mechanical power consumed by the oil pump is thereby reduced. This has the disadvantage that, during a warm-up phase, the oil pressure at the piston spray nozzles is relatively low and, due to the low engine speeds, no piston spray cooling takes place. However, if oil spilled out through the piston spray nozzles, faster heating of the oil would take place, which, in combination with improved insulation isolating the oil gallery and crankcase or crankshaft, would result in significantly improved oil heating. Since the openings of the cooling nozzles are relatively small, only a small portion of the total oil flow can pass through plunger nozzles, usually less than 30%, while plunger spray cooling is active.

According to a further advantageous development, the heat source may comprise a piston-spray cooling of an internal combustion engine, wherein an oil volume flow which is injected by piston spray nozzles to the underside of the pistons of the internal combustion engine, the largest oil volume flow in Represents engine lubrication system, but at least represents 30% of the funded by the oil pump oil flow. In this case - if a catalyst is provided - the Kolbenspritzdüsenölvolumenstrom be reduced as soon as the catalyst temperature is below a light-off temperature limit, ie Anspringgrenzwerttemperatur of the catalyst and Kolbenspritzdüsenölvolumenstrom can be reduced, in particular set to zero as soon as a predefinable limit oil pressure is reached. Increasing the orifice nozzle cross-sections that are larger than normal with oil flow through the piston orifice being greater than 30% of the total oil flow of the engine oil pump can effectively inject heat into the engine oil, regardless of engine speed, by controlling the oil flow rate through the piston injectors to get promoted. If the oil spray nozzles are open during the cold start phase, the oil may heat up more quickly when sprayed on the underside of the pistons, which are the warmest region of the engine, thus providing significantly improved lubrication in the cold start phase.

In many cases, in an internal combustion engine, waste heat is conducted through the cylinder walls to water jacket cooling, the heat being dissipated by a water cooler of a coolant loop. According to an advantageous development, the heat source may comprise at least part of an oil line, in particular a non-insulated oil line, between a combustion chamber of an internal combustion engine and a coolant channel. In particular, the oil line between a cylinder bore of the internal combustion engine and a coolant channel can be arranged in the upper region of the cylinder bore, wherein the distance between the lower end of the oil line and the upper end of the cylinder bore, which is sealed with the seal of the cylinder head, a maximum of 50% of the piston stroke is.

According to the above development, at least a part of the oil line, the is arranged between the combustion chamber and the coolant channel, be isolated on one side from the inside to the side of the coolant channel. The thermal conductivity of the one-sided insulation can be significantly lower than the thermal conductivity of the structural environment and preferably at least less than 1 W / (m K). The oil line can in particular run parallel to the cylinder center axis.

• Sofern das Öl eine höhere Temperatur als das Kühlmittel hat, wird die Zylinderwandtemperatur erhöht, was den Verbrennungsprozess deutlich erhöht und Wärmeverluste durch die Zylinderwand reduziert.
• Das Öl wirkt als Isolation, was die Zylinderwandtemperatur zusätzlich erhöht.
• Das durchgeführte Schmieröl wird deutlich stärker erwärmt, was die Reibung verringert und den Kraftstoffverbrauch reduziert.

If oil ducts are arranged between the cylinder inner wall and the water jacket cooling, various advantages can be achieved:

• If the oil has a higher temperature than the coolant, the cylinder wall temperature is increased, which significantly increases the combustion process and reduces heat losses through the cylinder wall.
• The oil acts as insulation, which additionally increases the cylinder wall temperature.
• The lubricating oil is heated much more, reducing friction and reducing fuel consumption.

In combination, for example, with a piston spray cooling and insulation of the oil galleries and the crankshaft and in particular by arranging a heat storage, can be dispensed with, for example, a complex exhaust gas heat exchanger.

If the oil channels are arranged parallel to the central axis of the cylinder, they can be relatively easily manufactured, for example, drilled later and no complex casts for the cylinder jackets for circumferential, horizontal channels to the central axis are provided, which carry the risk that by residues of molding sand sensitive parts of the valve train as the bearings or solenoid valves of camshaft adjuster can be damaged. Furthermore, effective heating can be achieved by a parallel course of the oil passages, since the oil flows from the colder, lower end to the hot, upper end region and thus a temperature gradient go through and can be heated accordingly hot. By a half-side isolation of the oil guide channels compared to the water jacket cooling, the efficiency of the proposed measures can be significantly increased.

According to a further advantageous development, a heat accumulator may be included for the transmission oil, which preferably has a chamber with a phase change material, and structurally integrates a coolant heat exchanger for heating the transmission oil with coolant in a unit.

The heat exchanger requires a large amount of space, and in a cold start phase, hot fluid stored in the tank is mixed with return fluid so that the total temperature within the heat accumulator is reduced because the hot oil is replaced with cold lubricating oil. For this reason, complex oil guide channels are provided in numerous heat accumulators to control the movement of the engine oil, such as in the DE 87108302 A is described.

It is advantageous to integrate a heat exchanger for at least two fluids in the heat accumulator with an already existing large volume and a correspondingly good insulation. In particular exhaust gas and / or coolant could be considered as heat-emitting fluid, as heat-absorbing fluid engine oil and / or gear oil come into question. Preferably, an exhaust gas / engine oil heat exchanger and a coolant / gear oil exchanger is conceivable, but also a combination thereof, for example a coolant / gear oil / engine oil heat exchanger or an exhaust / engine oil / gear oil heat exchanger. The at least two fluids may advantageously be coupled together by a chamber having a phase change material. A phase change material helps to set a preferred coupling temperature and to store heat or cold. The absorption of heat from the heat-emitting fluid melts the phase change material and the heat-emitting fluid is cooled. As the temperature decreases, the phase change material again freezes by dissipating heat to the heat receiving fluid, so that this is heated. The result is a storage of heat energy, a delayed heat transfer and a preferred heat transfer temperature.

Placed on the gear lubrication system with the heat storage can be designed as a plate heat exchanger in a further advantageous embodiment of the invention with the heat storage integrated coolant heat exchanger, in each case the two outer first plates lead coolant and between the next, second plate is guided inward transmission oil and between the next, third plate inwardly a phase change material is arranged, and between the next, fourth plate inwardly engine oil is guided, further preferably between a respective next, fifth plate inside a phase change material is arranged, and further between each In the next, sixth plate in gearbox oil is guided, and further between a respective next, seventh plate is guided inwardly coolant, the sequence of further layers as mentioned above beliebi g can continue. It is alternatively conceivable to carry out the coolant heat exchanger as a tube heat exchanger, wherein for example in an inner tube coolant, in a concentrically guided outer hollow cylinder wall gear oil in another concentric Hohlzylinderwandung a phase change material and in another concentric Hohlzylinderwandung engine oil. If necessary, the concentric structure of the tube heat exchanger can be repeated or the tube heat storage can be performed meandering.

By using a simple plate heat exchanger technology, in which various fluids such as engine oil, gear oil, coolant, phase change material are guided in different layers, wherein the hottest fluid is flanked by phase change material, which in turn is flanked by transmission oil and this in turn is flanked by cooling fluid and the Flow of all these fluids is controlled so that the transmission oil stops flowing when an engine oil temperature falls below a predetermined engine oil limit and the coolant fluid stops flowing when a cooling temperature falls below a predetermined cooling temperature limit, improved heating of the various lubricating oils and lower exhaust emissions and Fuel consumption can be achieved.

One or more valves, in particular a coolant valve and / or a transmission oil valve for controlling the fluid flow through the various channels of the heat accumulator may be provided on the transmission lubrication system with the heat accumulator so that a coolant supply is interrupted when the coolant temperature is lower as a first coolant limit temperature, in particular 90 ° C and when the transmission oil temperature is higher than the coolant temperature, and that the transmission oil supply is interrupted when an engine oil temperature is below a first engine oil limit temperature, in particular less than 120 ° C.

In a further advantageous development, the transmission oil supply to the heat accumulator can be opened to the transmission lubrication system with the heat accumulator as soon as the engine oil temperature reaches a second heat exchanger engine oil limit temperature, in particular greater than 120 ° C. Furthermore, the transmission oil supply to the heat accumulator can be closed as soon as the engine oil temperature has reached a lower third heat exchanger engine oil limit temperature, in particular less than 90 ° C. In addition, preferably a cooling water supply to the integrated heat accumulator can be opened as soon as the transmission oil temperature is lower than the coolant temperature and the cooling water supply to the integrated heat accumulator can be closed as soon as the transmission oil temperature is greater than the coolant temperature.

Exhaust gas heat exchangers are relatively expensive and complex because they have high temperatures and high pressures and the risk of leaks or fire have to counteract. It must take costly measures to prevent corrosion and pollution by the exhaust gases and an accumulation of water that can freeze must be prevented. By a one-piece design of an exhaust gas heat exchanger of engine oil and transmission oil in a single unit, an exhaust gas bypass line is arranged with exhaust bypass valve, so that a passage of exhaust gases through the exhaust oil heat exchanger is switchable, provided that the engine oil temperature or the transmission oil temperature reaches a maximum, optimal control of Heating can be achieved especially at high loads and the cold start phase. This in turn can be achieved an improved lubrication.

According to an advantageous development of the invention, an exhaust / oil heat exchanger for engine oil and transmission oil can be made in one piece. It may also be advantageous if the heat exchanger is flowed through in the countercurrent principle, in particular engine oil and gear oil flow through the heat exchanger in countercurrent, and preferably the region of the transmission oil-exhaust heat exchanger downstream of the range of engine oil exhaust gas heat exchanger is arranged. The exhaust gas / oil heat exchanger may be provided on the exhaust side with an exhaust gas bypass line and at least one exhaust gas bypass valve, so that an exhaust gas flow through the region of the engine oil exhaust gas heat exchanger at a predefinable first heat exchanger engine oil limit temperature, in particular of 120 ° C, is interrupted. The exhaust gas flow can be interrupted by the region of the transmission oil-exhaust heat exchanger when a predefinable first heat exchanger transmission oil limit temperature, in particular 90 ° C., is exceeded.

The integration of transmission and engine oil heat exchanger in a unit with a housing with a switchable Abgasbypassleitung heating / cooling of the oil can be controlled by influencing the exhaust gas flow. Thus, the exhaust stream can be passed through the bypass line, if the engine oil or the transmission oil has reached a limit temperature.

Common coolant has the disadvantage that at maximum temperatures in the combustion chamber there is a risk of the coolant starting to boil, so the combustion chamber wall temperatures must be limited to prevent individual components from being thermally overloaded and from local overheating or damage to prevent the engine.

According to a further advantageous embodiment of the invention, the coolant of the coolant circuit may comprise a phase change material having a melting temperature above 0 ° C and a boiling temperature of at least 120 ° C, in which the density increases with increasing temperature, in particular during the phase transition from solid to liquid , The coolant circuit filled with this phase change material can be integrated in the internal combustion engine to be cooled in such a way that no connecting lines leading to other components are present. In this case, a first coolant circuit with the phase change material can be surrounded by a second coolant circuit and cooled by it, wherein the second coolant circuit is filled with coolant having a melting temperature of at least below -30 ° C, and the second coolant circuit can be arranged outside the internal combustion engine components, in particular a cooler.

A phase change material may provide a higher boiling temperature than water so that the use of such material in the coolant system allows a higher peak temperature in the combustion chamber. However, phase change material has a low specific heat capacity and a lower thermal conductivity or both, so that large radiators, pumps and connecting lines are required in the cooling circuit. Furthermore, no phase change material can be used, which assumes a fixed state of aggregation at ambient temperatures between -40 ° C and 0 ° C, since in the solid state at high loads no waste heat can be transported to the radiator. For this purpose, it is first necessary that the phase change material melts, which is difficult to achieve, especially in the parts of the cooling system, which are outside the internal combustion engine, for example in the radiator. Therefore, it is proposed in the aforementioned embodiment that a phase change material having a melting temperature between 40 ° C and 120 ° C is used, which is used only within an inner cooling circuit, so that the phase change material in a cold start phase very quickly reaches its melting point and becomes liquid and During the cold start phase can already dissipate heat. The inner cooling circuit is connected to an outer cooling circuit through a heat exchanger, wherein in the outer cooling circuit, for example, conventional coolant having a melting temperature of below -30 ° C can be used. As a result, the advantage of an increased interior temperature can be achieved and still a stable and efficient cooling in a lubrication system with improved insulation can be used.

A cooling system with separate cooling circuits for improved heating, wherein the coolant through a cylinder head and through a cylinder block run separately, for example, from JSAE Review 23 (2002) p. 507-511 known. During a warm-up phase, for example, the coolant circuit may be interrupted by the cylinder block or engine block, wherein at higher temperatures, the coolant flows through the cylinder head in parallel through the cylinder block and from there to the radiator. However, this involves the disadvantage that the coolant does not move during a cold start phase in the cylinder block and thus local overheating may occur, especially under high engine load during the cold start. Furthermore, due to convection, the refrigerant is disadvantageously moved to flow from top to bottom in a combined flow of cylinder head to the cylinder block and thus in the opposite direction to the convection, ie the heat flow, which acts from bottom to top, which the flow resistance on the Motor pump increases and an additional mechanical load and additional electrical consumption of the water pump conditionally.

According to an advantageous development, a cylinder-head coolant channel and a cylinder block coolant channel of the cooling circuit of an internal combustion engine may be structurally separated in order to achieve an acceleration of the coolant heating. In this case, during a warm-up phase below a first coolant limit temperature, in particular below 90 ° C., a coolant first flows through the cylinder head for heating and from there through a cylinder / engine block, where the warm coolant heats a cylinder wall to reduce wall heat losses, and there it fed to a coolant pump. When the first coolant limit temperature is reached, a first coolant flow direction thermostat can be opened in the cylinder head, and at least one partial volume flow of the coolant can be routed to a radiator. Upon reaching a second coolant temperature limit, in particular above 100 ° C, a second Kühlmittelstromrichtungsthermostat, in particular a 3-way thermostat at the previous output of the cylinder / engine block connect to the input of the coolant pump and connect to the output of the coolant pump, so that the coolant in the cylinder / engine block in the opposite direction as the coolant flows in the cylinder head, and a combined coolant flow from the cylinder head and cylinder / engine block is passed through the radiator.

Accordingly, in the proposed embodiment, the coolant is first passed through the cylinder head, wherein at the end of the cylinder head, the coolant is fed back into the engine block, so that the cylinder block is also heated by the already heated in the cylinder head coolant and thus takes place an improvement of the combustion process, since the cylinder head typically heats up much faster and is warmer than the cylinder block - also due to the fact that the water jacket cooling in the cylinder head occupies much less space and hot exhaust gases are also passed through the cylinder head - so that the largest heat there arises. In a further step, the coolant can heat up faster. If the coolant is warm enough, a coolant thermostat may change the coolant flow direction such that coolant flows through a water cooler, and when the engine block becomes warm enough, the coolant may flow in parallel through the engine block and cylinder head for maximum cooling by the water coolers can. Thus, a sufficient cooling and a rapid heating or a uniform heating of the engine block is achieved, so that the lubricating oil is heated faster.

In a further embodiment of the lubricating system, it is proposed that the piston of an internal combustion engine is insulated on the inside of at least one piston skirt by insulation, the thermal conductivity of the insulation being 5% or less than the thermal conductivity of the piston skirt, and preferably at least less than 1 W / (FIG. m K), wherein preferably the inside of the piston crown is not isolated. Thus, it is proposed to isolate an oscillating component to be lubricated, so that the piston stem assigned in the cold start phase of a cold cylinder sidewall is isolated, but the rapidly heating piston crown is not insulated. Thus, additional heat input into the oil can be provided and isolation to prevent cooling from the cold cylinder block can be achieved. In particular, in a piston injection cooling, in which a large amount of oil comes into contact with the piston head, such an insulated piston for rapid heating is advantageous.

If a heat storage is provided to store oil in a desired temperature range between, may advantageously be provided for heating or cooling an exhaust gas heat exchanger, which is at least three-volume or three-channel or with three chambers, and the structurally integrated in the heat storage (14) can be. The exhaust gas heat exchanger may comprise a first volume that can be flowed through by at least a first partial exhaust gas flow, wherein the first volume through a first partition wall is limited or surrounded by a first partition, wherein on at least one of the sides of the first partition, which is not in communication with the exhaust partial flow, a phase change material may be arranged in a second volume bounded by a second partition or surrounded by a second partition is, wherein on at least one of the sides of the second partition, which is not in communication with the phase change material, lubricating oil is flowable through a third volume. An arrangement order of first, second and third volumes or channels in reverse order (ie, the order: first volume, second volume, third volume, second volume, first volume, second volume, third volume, etc.) may be repeated at least once, in particular to be continued. The phase change material may comprise at least one sugar alcohol such as erythritol, threit or a paraffin, or a salt such as a hydrate, nitrate, hydroxide or a chloride such as magnesium chloride hexahydrate or magnesium nitrate hexahydrate, whose latent heat of fusion is greater than the heat which the heat storage due to the temperature difference of a first lower oil limit temperature of 50 ° C and a first upper oil limit temperature of 90 ° C can save. Advantageously, the melting temperature of the phase change material may be lower than the first upper oil limit temperature, and preferably, if the melting temperature of the phase change material is greater than 100 ° C, the phase change material erythritol with a melting temperature of about 120 ° C, so that in cold start a highest possible temperature in Heat storage can be reached in a short time. By such, integrated in the heat accumulator three-chamber heat exchanger with an indirect coupling of oil and exhaust gas via a phase change material direct heat transfer from very hot exhaust gas to the oil is bypassed because the phase change material serves as a heat buffer. As a result, a local overheating of the oil by the phase change material (PCM - phase change material) is prevented as a damping layer. Furthermore, an increase of the insulation and sealing is provided, so that a direct contact of oil and exhaust gas is prevented. The PCM material, for example magnesium chloride hexahydrate (MgCl2 x 6 H2O) is incombustible and thus reduces the risk of ignition. The exhaust gas heat exchanger can be constructively designed as a simple plate heat exchanger and integrated in the heat storage. The insulation of the heat accumulator insulates the heat exchanger so that it can ensure effective heat transfer very quickly during a cold start without the exhaust gas having to heat up the wall of the heat exchanger itself.

The aforementioned heat exchanger can preferably be designed as a tube heat exchanger, be configured with at least three telescoped tubes. Thus, the tubes may be double-walled and be arranged a phase change material in the space between the inner tube and the outer tube. As a result, a separation, compact design and ease of manufacture can be easily achieved. If leakage did occur, it would be ensured that no liquid could escape into the heat accumulator since leakage could at most reach up to a PCM chamber.

In an advantageous development of the aforementioned embodiment with heat accumulator with integrated exhaust gas / oil heat exchanger, at least one of the exhaust gas connection lines of the exhaust gas heat exchanger integrated in the heat accumulator can be insulated from the heat accumulator by a ceramic line. As a result, the insulation effect is further improved, thereby reducing heat losses.

In an advantageous development, an oil feed line of a cylinder head and / or a turbocharger downstream of the heat source may be connected to a cylinder block oil gallery. Furthermore, a coolant heat exchanger can be arranged in the oil supply line of the cylinder head and / or the turbocharger, which can be flowed through by coolant of a coolant circuit. By guiding the cylinder head and turbocharger oil supply line downstream of the heat source, the oil temperature in the cylinder head and turbo be kept at a low level, since the oil has a lowest possible temperature before heating by the heat source. This reduces friction in the valve train in the cylinder head, since mixed friction is avoided, especially at the low speeds in the valve train. In the turbocharger, the risk of oil leakage in the intake side is reduced, so that a tendency to ignite by oil particles is reduced, especially in gasoline engines with direct injection.

In a further advantageous embodiment, a flow rate of the oil pump can be regulated, wherein a flow rate of the oil pump is increased in order to achieve an increased pumping volume flow within a heat accumulator as soon as an oil outlet temperature of the heat accumulator is below a predefinable oil leakage temperature of maximum 90 ° C and an oil inlet temperature of the Heat accumulator is above a predefinable oil inlet temperature limit of at least 90 ° C. It has been found that in the case of an aforementioned relatively high oil temperature in the oil circuit hardly comes to a displacement of the cold oil by the incoming hot oil, since the hot oil flows through short circuit through the cold oil. Therefore, in the case of a hot oil, especially in a hot phase, it is advantageous to increase the oil flow rate by increasing the pump delivery rate to produce a higher flow rate of the hot oil and thus turbulent flow, better displacing the cold oil with its laminar flow becomes.

DRAWINGS

Further advantages result from the present description of the drawing. In the drawings, embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art expediently also the features individually consider and summarize to meaningful further combinations.

Fig. 1

ein erstes Ausführungsbeispiel eines erfindungsgemäßen Schmiersystems;

Fig. 2

ein zweites Ausführungsbeispiel eines erfindungsgemäßen Schmiersystems;

Fig. 3

ein Ausführungsbeispiel eines Wärmespeichers für ein erfindungsgemäßes Schmiersystem;

Fig. 4

ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Schmiersystems;

Fig. 5

ein Ausführungsbeispiel einer Ölschmierleitungsführung im Zylinderkopf einer Verbrennungskraftmaschine für ein erfindungsgemäßes Ölschmiersystem;

Fig. 6

ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Schmiersystems;

Fig. 7

Ausführungsbeispiele eines Kühlmittelkreislaufs zum Einsatz in einen erfindungsgemäßen Schmiersystem;

Fig. 8

Ausführungsbeispiele eines teilisolierten Kolbens einer Verbrennungskraftmaschine zur Verwendung in einem erfindungsgemäßen Schmiersystem;

Fig. 9

ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Schmiersystems.

Show it:

Fig. 1

a first embodiment of a lubrication system according to the invention;

Fig. 2

a second embodiment of a lubrication system according to the invention;

Fig. 3

an embodiment of a heat accumulator for a lubricating system according to the invention;

Fig. 4

a further embodiment of a lubricating system according to the invention;

Fig. 5

an embodiment of an oil lubrication line guide in the cylinder head of an internal combustion engine for an inventive oil lubrication system;

Fig. 6

a further embodiment of a lubricating system according to the invention;

Fig. 7

Embodiments of a coolant circuit for use in a lubrication system according to the invention;

Fig. 8

Embodiments of a partially insulated piston of an internal combustion engine for use in a lubrication system according to the invention;

Fig. 9

a further embodiment of a lubrication system according to the invention.

In the figures, identical or similar components with the same reference numerals quantified.

Fig. 1 shows a first embodiment 100 of a functional structure environment lubrication system 11 according to the invention, in particular for lubrication points such as oil gallery, crankshaft, bearings or a metallic structure environment 63 such as gear parts with metal environment and housing. Such a lubrication system can be used for example in a vehicle with an internal combustion engine, an electric vehicle or a hybrid vehicle. By way of example, a crankshaft housing can be considered in which the crankshaft, bearing shell, connecting rod and housing form a metallic environment whose high specific thermal conductivity removes heat from oil at low ambient temperatures. Internal insulation of these areas, especially areas in contact with outside air, can accelerate heating of the oil.

In Fig. 1 Lubricating oil is stored in an oil reservoir 1, which is sucked in via an oil strainer 2 and an electrically controlled pump 4. To avoid overpressure, a pressure relief valve 5 is arranged downstream of the pump outlet, which in a case of overpressure in the oil lubrication circuit allows the oil to flow back into the oil reservoir 1 via the pump 4. The oil is passed through another oil filter 6 and via a heat source 7, in this case an exhaust gas oil heat exchanger, which has a thermal energy supply line 8 and a residual energy stream discharge line 9. This may be, for example, a supply pipe and an exhaust pipe between a catalyst of an internal combustion engine and the exhaust. Alternatively, the heat source 7 may also be a heat exchanger between the oil lubrication system and the coolant circuit, whereby the lubricating oil can be warmed up more in a cold start phase. After the heat source 7, at least one connecting line connects with lubrication points 11 or oil gallery line 10, which supplies the points to be lubricated with lubricating oil and having an inner thermal insulation 13, wherein an oil-carrying inner part 12 of the oil gallery 10 out is. Thus, the outer diameter D is substantially less than the inner diameter d, since the insulation is directed inward and reduces the cross-section, so that the surface-to-volume ratio is improved and the release of heat energy to the metal environment or structural environment 11, 63 is reduced. In addition, housing inner walls, oscillating components or other metal areas with which lubricating oil may come into contact may be provided with an insulating layer. After performing the heated by the heat source 7 oil through an isolated environment to be lubricated points, the oil is returned to the oil reservoir 1, where it is available for the recycle. By thermal insulation of oil gallery 10, lubrication points 11 and structural environment 63 after the heat source 7, the release of thermal energy to the metal environment, such as cylinder head or cylinder block is significantly reduced, so that when heated in a cold start phase, a low viscosity and thus a reduced Friction can be achieved, resulting in a reduced fuel consumption and reduced exhaust emissions of the internal combustion engine. In the case of a transmission, the structural environment 11, 63 oil reservoir and gear tray with gear housing and causes an improved smoothness of power transmission. In addition, the oil reservoir 1 may be thermally insulated and further parts, such as to be lubricated rotating or oscillating components and the surrounding housing to be isolated. Advantageously, the areas arranged after the oil pump 4 are largely thermally insulated, in particular the pressurized oil circulation area and the areas in which the heat is supplied by the heat source.

Building on the in Fig. 1 illustrated embodiment shows Fig. 2 a further development of a lubrication system according to the invention, based on the structure of the lubrication system 100 of Fig. 1 builds up, and can be used comparably. In addition to that in the Fig. 1 shown configuration is in the oil suction 3 between the oil reservoir 1 and oil pump 4 is a thermally insulated Heat accumulator 14 is arranged, which is connected in parallel to the oil suction pipe 3, and which can be switched via a three-two-way valve 15 in the Ölsaugrohrleitung 3. In the thermally insulated heat accumulator 14, oil may be temporarily stored in a heated state to maintain the heat and associated reduced viscosity, allowing for improved heating in the thermally insulated structural environment such as lubrication points 11 and metallic environment 63 such as housings, components, etc. becomes. For example, during a cold start, oil can be removed from a heat accumulator 14, which has a residual heat and thus a lower viscosity than the oil in the oil accumulator 1, which absorbs the ambient temperature. Such a heat accumulator 14 can be carried out highly insulated, for example, vacuum insulated, and mixes with the flow of oil with freshly inflowing cold oil, the mixing temperature of the oil in the heat accumulator 14 decreases.

To a heat storage, for example, as in Fig. 2 can continue to improve, as shown in Fig. 3 represented a thermally highly insulated heat accumulator 14 may be used, which comprises a freewheel piston 19 and the cylindrically executed heat accumulator 14 divides into two slidably large chambers 16 a and 16 b. In the chamber 16b, for example, cold oil can flow and be stored in the chamber 16a warm oil. When removing the warm oil 16a, the thermally insulated freewheel piston moves to the left and cold oil can flow into the chamber 16b, so that the pressure conditions in the heat accumulator 14 remain constant. By a four-way valve 20, various modes for the heat-insulated oil reservoir 14 can be adjusted. Thus, a removal position in the left position, in the middle position, a connection of the two chambers and a right Aufladeposition in the chamber 16 a filled with oil from a heat source 7 and oil from chamber 16 b can be discharged back into the oil reservoir 1, adjustable. The two chambers are connected to prevent over-pressure with biased check valves 22, 23, so that an overpressure in one Chamber in the other chamber can be dismantled. The insulation 17 can be carried out very expensive, eg as a vacuum insulation, so that a temperature loss, for example, from 100 to 80 ° C at 25 ° C ambient temperature within more than 6 hours. This ensures that at least for a short-term parking of a vehicle of less than 24 hours, a sufficiently warm amount of lubricating oil is available to ensure optimal lubrication even in the cold-start phase.

In the Fig. 4 a further embodiment 100 of a lubrication system for an internal combustion engine is shown, which basically the structure of in Fig. 1 shown lubrication system 100 corresponds. In addition to the embodiment of the Fig. 1 is between the oil filter 6 and the heat source 7, which is designed as exhaust gas heat exchanger 60, another heat exchanger 24 is provided as a coolant heat exchanger, which is connected to a cooling circuit 61 via a two-two-way valve 25 switchable. A heat input can take place via the cooling circuit 61 as well as via the exhaust gas heat circuit into the heat source 7. Via a suction line 26, a fuel-air mixture enters a cylinder head 27 of an engine block 36, whereupon the exhaust gas is passed through a catalyst 28 into an exhaust pipe 55. In the exhaust pipe 55, a three-two exhaust bypass valve 29 is arranged, in which the exhaust stream can be passed through the Abgasmotorölwärmetauscher 7, 60 or on the other via an exhaust gas bypass line 30 can be fed directly to the exhaust 31, in particular if a minimum temperature of Oil is reached. Thus, via the two switching valves, the coolant valve 25, which is arranged downstream of the oil reservoir 1 in the oil circuit and via the exhaust oil heat exchanger 7, 60 which upstream to the oil gallery 10 and lubricating components 63 and lubrication points 11 is arranged, a heat input into the engine oil take place so that heated by the highly isolated oil gallery in the structural environment 11, 63 and thereby highly viscous oil can be distributed to the points to be lubricated before the oil is returned to the oil reservoir 1.

In the Fig. 5a schematically an internal combustion engine 41 with engine block 36 and components such as cylinders with crankshaft 67, connecting rod 64 and piston 66 and cylinder block and cylinder head 27 shown with intake and exhaust valves. The engine block 36 has a cylinder center axis 58, wherein the cylinder head 27 has a cylinder head flange 35, a combustion chamber 34 and the engine block has a cylinder bore 38 in which the connecting rod 64 connects the crankshaft 67 with the piston 66. The cylinder jacket has a water jacket cooling 65 with channels 37 for cooling liquid, which, for example, in the Fig. 5b are shown as the coolant channel 37.

In the Figs. 5b and 5c only two embodiments of oil guide pipe of a lubrication system 32 are shown, which extend in the upper region of the combustion chamber 34 in the height of the half cylinder 33 between Zylinderaußen- and cylinder inner wall 62 and the coolant channel 37 of the water jacket cooling 65. In the upper region of the half cylinder stroke in the cylinder is the combustion chamber 34, which is the fastest heating component in the internal combustion engine 41, so that lubricating oil can be heated there particularly effectively, and this can serve as a heat source 7 for improved lubrication, especially during a cold running phase. It shows Fig. 5b non-insulated oil lines 32, which can absorb heat of the cylinder wall and the combustion chamber 34 thermally isolated from the coolant passage 37. In the Fig. 5c a further embodiment is shown, which is a unilaterally insulated oil passage 32, 56, wherein the oil guide line is half insulated from the coolant channel 37 and thus can be heated faster and provides better insulation of cylinder wall 62 against the coolant channel 37, while heat the cylinder inner wall 62nd can be registered in the oil.

Fig. 6 shows based on the embodiment of the Fig. 1 another lubrication system 100, in addition to the in Fig. 1 Components shown a highly insulated pressure heat accumulator 14 in the pressurized area of the Oil lubrication line after the heat source 7, which is arranged in front of the heat-insulated structure environment 11, 63 with oil gallery 12. Heated oil can be added to the heat storage 14 switchable by the three-two-way valve 15, and be released if necessary, for example, in the cold start phase again. Unlike the in Fig. 2 illustrated embodiment, the heat accumulator 14 is disposed in the pressure range of the oil lubrication system 100, so that in particular when approaching a short-term shutdown of max. one to two days of highly viscous warm oil is available for lubrication, which need not be heated by a heat source 7. Unlike the in Fig. 2 shown heat accumulator 14 is the in Fig. 6 illustrated heat accumulator 14 designed for high pressures and may have a different construction.

The Fig. 7 shows a coolant circuit 61 in the coolant through an internal combustion engine 41 along two coolant channels 37 through a cylinder head 27 and through an engine block / cylinder block 36 can be performed. The heat of the cooling circuit can be discharged via a radiator 45 to a second coolant circuit 57 or to an air flow. A coolant pump 39 forces the coolant to circulate in the coolant circuit 57, and two switching valves, namely, the two-two coolant flow direction thermostat 44 and the three-two coolant flow direction thermostat 40, determine the direction and type of the coolant flow through the cylinder head 27 and engine block 36.

In the Fig. 7a is shown that, for example, in a cold start phase, the coolant via the coolant pump 39 first flows back through the cylinder head 27 and locked Kühlmittelstromrichtungsthermostat 44 through the engine block 36 so that a closed circuit is formed, in which no external cooling takes place and the coolant flow in anti-parallel through the Coolant channels 37 of the cylinder head 27 and engine block 36 flows.

Fig. 7b shows a second switching option for a partial load range, in the a coolant flows through the cylinder head 27 and thereafter branched antiparallel through the engine block 36 back to the coolant pump 39 and partially via a -Wassererkühler 45 flows, whereby the cylinder head 27 well cooled and engine block 36 can be cooled less.

In the Fig. 7c For example, a third shift variant for a full load operation is shown with the first coolant direction thermostat 44 open and the second coolant direction thermostat 40 also open so that the coolant flow can flow in parallel through the cylinder head 27 and engine block 36 so that maximum cooling performance can be provided. The in the three switching variants in Fig. 7a, 7b and 7c shown configurations can be switched at different load or cold and warm start phases of an internal combustion engine, wherein Fig. 7a in a cold warm-up phase can serve for rapid warming. Fig. 7b in a medium operating phase a low cooling effect and Fig. 7c represents a cooling circuit with a maximum cooling effect, so that the oil of a lubrication system can be heated quickly in all load cases and can achieve a low viscosity and optimum lubrication effect.

Further shows Fig. 8 a piston 66 of an internal combustion engine 41, which has an insulation 13 on the inside of the piston skirt 102 in an annular manner, which thermally insulates the piston skirt 102 from the cylinder inner wall 62. The thermal conductivity of the insulation 13 is 5% or less than the thermal conductivity of the piston skirt 102. In contrast to the piston skirt 102, the inside of the piston crown 103 is not insulated. As a result, the piston head 103 can heat up quickly in a cold start phase, wherein, for example, when using a piston spray cooling oil which is injected onto the underside of the piston, can be heated very quickly.

The Fig. 9 FIG. 12 illustrates a wide embodiment of a lubrication system 100 that is substantially the embodiment of the present invention Fig. 1 equivalent. The shingles a structural environment 11 of an internal combustion engine include an oil gallery 10 with an oil-carrying inner part 12, which is supplied by the oil gallery 10 with lubricating oil. An oil supply line 104 branches off from the oil gallery 10 and lubricates a cylinder head 27. The oil supply line 104 of the cylinder head 27, which could also lubricate a turbocharger, is connected to the cylinder block oil gallery 10 downstream of an exhaust heat exchanger 60 as a heat source 7. In the oil supply line 104 of the cylinder head 27, a coolant heat exchanger 24 is arranged. The coolant heat exchanger 24 is connected to an inlet and outlet 61 a, 61 b of a coolant circuit 61, which can cool or heat the lubricating oil as needed. For this purpose, a coolant control valve 25 is provided to control the heat exchange of the coolant heat exchanger 24.

It should be noted that the isolated oil ducts are located in an oil supply area behind the oil pump, i. are arranged in the pressurized line area. This line has a larger circumference than the inner diameter of the line, at least in some areas, so that an improved surface volume ratio can be achieved. The insulation may preferably be made of plastic or ceramic and may be arranged internally or externally. The thermal conductivity of the isolated regions of the connecting line is 5% or less than that of the surrounding metal structure or oil gallery, in particular steel or cast iron having a thermal conductivity of about 50 W / mK and thus the insulation has a thermal conductivity of 2.5 W / mK, preferably 1 W / mK or less should have.

The other areas to be isolated in addition to supply lines and the lubrication points are in particular gearbox or in an internal combustion engine, the crankcase, the oil pan and the oil gallery. For the thermal isolation of rotating or oscillating components are in particular crankshaft, crankshaft bearings and crankcase, camshafts and bearings and gear shaft and gears - preferably isolating the areas that are regularly wetted with oil in functional use. It is advantageous if no fresh air enters the crankcase, so that it is closed to the cold outside air, and possibly blow-by gases leak, but no cold fresh air can penetrate into the crankcase to allow increased or accelerated heating.

By combining two heat exchangers of engine oil and gear oil and / or two heat storage for engine oil or gear oil can achieve a higher-quality insulation and increased component quality against leakage or corrosion in a unit, which critical space can be saved. If a phase change material is used in the cooling circuit, then it is advisable to provide a second enveloping cooling circuit, wherein the first cooling circuit can be operated at elevated temperatures, and the second cooling circuit serves to cool the inner cooling circuit, wherein a freezing or a solid state the phase change material can be prevented, so that an operability can be achieved even at very low outdoor temperatures.

Claims (15)

1. Lubrication system (100) for the lubrication of rotating or oscillating components having at least one oil suction pipe, which is arranged in an oil reservoir (1), an oil pump (4) connected to the oil suction pipe (3), and a heat source (7) connected to the oil pump (4) and downstream thereof further connecting lines (10) for supplying oil to lubrication points (11) which are structurally integrated in a metallic structural environment (63) of a metal housing, after which the oil is returned to the oil reservoir (1),
   characterised in that
   at least one connecting line (10) between the heat source (7) and the lubrication point (11) downstream of the heat source is insulated on the inside wall by an internal insulation (13), wherein the thermal conductivity of the internal insulation (13) is 5% or less than the thermal conductivity of the connecting lines or of the rest of the structural environment (63), and the heat source (7) is switched off or at least reduced in its heat output when a first upper oil limit temperature is reached.
2. System according to claim 1,
   characterised in that
   the thermal conductivity of the internal insulation (13) is less than 1 W/(m·K), or in that the outer circumference of the connecting line (10) is at least twice as large as the inner circumference of the connecting line (10).
3. System according to one of the previous claims,
   characterised in that
   the housing of the lubrication system or of the oil reservoir (1) is insulated by an internal insulation (13), wherein the thermal conductivity of the internal insulation (13) is 5% or less than the thermal conductivity of the structural environment (11, 63), or in that the oil reservoir (1) is made completely or at least partially from an insulating material and the thermal conductivity is less than 1 W/(m·K).
4. System according to one of the previous claims,
   characterised in that
   a highly insulated thermal reservoir (14) with a thermal conductivity of less than 0.01 W/(m·K) is comprised, which is arranged between the oil suction pipe (3) and the oil pump (4) or between the oil pump (4) and the heat source (7), or between the heat source (7) and a lubrication point (11).
5. System according to claim 4,
   characterised in that
   the thermal reservoir (14) is designed cylindrical and comprises a free piston (19) of thermally insulating material that divides the thermal reservoir (14) into two chambers (16a, 16b), whereby when filling the thermal reservoir (14) with oil above a first upper oil limit temperature of at least 90 °C into the first chamber (16a), a volume of oil is pushed back from the second chamber (16b) into the lubrication system (100) and when the oil is emptied from the first chamber (16a) in a cold-starting phase under a first lower oil limit temperature of at most 50° C into the lubrication system (100), the second chamber (16b) is filled with oil, so that the oil level in the oil reservoir (1) is thus only affected to an insignificant extent, and the thermal reservoir (14) is usable when required as a heat source and as a heat sink.
6. System according to one of the previous claims,
   characterised in that
   the lubrication system (100), oil reservoir (1) and structural environment (11, 63) is enclosed within a combustion engine (41) or a transmission, and in that the heat source (7) is provided by a combustion engine (41) or an electric battery or by an inverter.
7. System according to claim 6,
   characterised in that
   the transmission is a manual transmission that does not comprise an oil pump (4), wherein a coolant heat exchanger (24) is arranged in the oil reservoir (1), so that the transmission oil is heated by the engine coolant, and in that the coolant heat exchanger (24) is provided on the coolant side with a coolant valve (25) which is closed when the temperature falls below a coolant limit temperature and is opened when the coolant limit temperature is exceeded, or the transmission is a manual transmission, and the oil pump function is provided by the displacement action of a pair of toothed wheels, wherein an oil pressure line is arranged on that side on which the two tooth faces move towards one another, and an oil return line is arranged on that side on which the two tooth faces move away from one another.
8. System according to claim 6,
   characterised in that
   the heat source (7) comprises a connecting line of the exhaust pipe (55) of a combustion engine (41) with the structural environment (11, 63), or the heat source (7) comprises a piston spray cooling, wherein an oil volume flow that is sprayed by the piston spray nozzles onto the pistons (66) of the internal combustion engine (41) represents at least 30% of the oil volume flow conveyed by the oil pump, wherein piston spray nozzle oil volume flow is reduced as soon as a catalytic converter temperature is below a "light-off" temperature limit value (activation limit temperature) and the piston spray nozzle oil volume flow is reduced as soon as the oil pressure falls below a predefinable limit.
9. System according to claim 6,
   characterised in that
   the heat source (7) comprises at least a part of an oil line (32) between a combustion chamber (34) and a coolant duct (37), wherein that part of the oil line (32) which is arranged between combustion chamber (34) and coolant duct (37) is insulated on one side from the inside to the side of the coolant duct (37), wherein the thermal conductivity of the one-sided insulation (56) is less than the thermal conductivity of the structural environment (11, 63), and less than 1 W/(m·K).
10. System according to claims 4 and 6,
    characterised in that
    a thermal reservoir (14) for the transmission oil is comprised which structurally integrates as one unit a coolant heat exchanger (24) for heating the transmission oil with coolant.
11. System according to claim 6,
    characterised in that
    an exhaust gas/oil heat exchanger (60) for engine oil and transmission oil is designed in one piece and at least one exhaust gas bypass valve (29) is provided, so that an exhaust gas flow through the area of the engine oil/exhaust gas heat exchanger is interrupted when a predefinable first heat exchanger/engine oil limit temperature is exceeded, and in that the exhaust gas flow through the area of the transmission oil/exhaust gas heat exchanger is interrupted when a first heat exchanger/transmission oil limit temperature is exceeded.
12. System according to one of the above claims,
    characterised in that
    the coolant of the coolant circuit (61) comprises a phase change material (46) that has a melting temperature above 0 °C and a boiling temperature of at least 120 °C, in which the density rises with rising temperature, and in that the coolant circuit filled with this phase change material (46) is integrated in the combustion engine (41) to be cooled in such a way that there are no connecting lines leading to other components, wherein the first coolant circuit (61) is surrounded by and cooled by a second coolant circuit (57) which is filled with coolant having a melting temperature of at least below -30 °C and which has components arranged outside the combustion engine (41).
13. System according to one of the above claims,
    characterised in that
    a cylinder head coolant duct (42) and a cylinder block coolant duct (43) of the cooling circuit (61) of a combustion engine (41) are designed structurally separate in order to speed up heating of the coolant, wherein during a warming-up phase below a first coolant limit temperature a coolant first flows through the cylinder head (27) to heat it and from there through a cylinder/engine block (36), where the hot coolant heats up a cylinder wall in order to reduce wall heating losses, and is passed from there to a coolant pump (39); and in that when the first coolant limit temperature is reached in the cylinder head (27) a first coolant flow direction thermostat (44) opens and passes at least a partial volume flow of coolant to a cooler (45), and when a second coolant limit temperature is reached a second coolant flow direction thermostat (40) closes a connection to the inlet of the coolant pump (39) and makes a connection to the outlet of the coolant pump (39), so that the coolant in the cylinder/engine block (36) flows in the opposite direction to that of the coolant in the cylinder head (27), and a combined coolant flow is passed from the cylinder head (27) and the cylinder/engine block (36) through the cooler (45).
14. System according to one of the above claims,
    characterised in that
    a piston (66) of a combustion engine (41) on the inside of at least one piston skirt (102) is insulated by an insulation (13), wherein the thermal conductivity of the insulation is 5% or less than the thermal conductivity of the piston skirt (102).
15. System according to claims 4 and 6,
    characterised in that
    the exhaust gas heat exchanger (60) is an at least three-volume exhaust gas heat exchanger which is structurally integrated into the thermal reservoir (14) and comprises a first volume through which can flow at least a first partial exhaust gas flow, wherein the first volume is limited by or is surrounded by a first partition wall, wherein on at least one of the sides of the first partition wall not in contact with the partial exhaust gas flow a phase change material (46) is arranged in a second volume which is limited by or is surrounded by a second partition wall, wherein on at least one of the sides of the second partition wall not in contact with the phase change material lubricating oil can flow through a third volume.

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