EP2751397B1 - Method and device for detecting leaks in a vehicle lubrication system - Google Patents

Description

The invention relates to a method for leak detection of a lubrication system for the lubrication of rotating or oscillating components of an internal combustion engine or a transmission, preferably automatic transmission of a vehicle. Furthermore, the invention relates to a device for heating a lubricating system of rotating or oscillating components for an internal combustion engine or a transmission, preferably automatic transmission for performing a method according to the invention.

STATE OF THE ART

From various publications it is known that by heating the lubricating oil with the aid of an exhaust gas / oil heat exchanger, fuel consumption and exhaust emissions can be significantly reduced.

Exemplary here on the DE 102009013943 A and the PCT / EP2010 / 0536 referenced, both of which propose the arrangement of 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 through fast heating areas of an internal combustion engine or a transmission is passed.

Furthermore, the financial contributions Will, F .: A novel exhaust heat recovery system to reduce fuel consumption, F2010A073, FISITA conference Budapest, Hungary 2010, as well as Will, F., Boretti, A.,: "A New Method to Warm Up Lubricating Oil to Improve Fuel Economy", SAE 2011-01-0318, 2011 directed.

In an internal combustion engine, the fuel consumption during a NEDC test in the cold state (starting temperature about 24 ° C) is about 10 to 15% higher than the same test with a lubricating oil temperature in a hot state of about 90 ° C, the so NEDC hot test mentioned. Among other things, this is due to the fact that the lubricating oil at lower temperatures has a higher toughness, and that of Fuel is condensed on cylinder walls and added to the lubricating oil. In addition, measures are taken to heat the catalyst faster, such as a retardation of the ignition, an increase in idle speed and enrichment with secondary air injection. In addition, the majority of the emitted exhaust emissions during the cold start phase of the internal combustion engine, if the catalyst has not yet reached the required operating temperature. At the same time a large part of the energy supplied is discharged unused as Abgasent-halpie. This is a total of about 30 to 40% of the energy of the fuel supplied.

It is known to accelerate the warm-up phase of an internal combustion engine by using exhaust gas heat exchangers, which in a complicated manner heat up the lubricating oil and reduce the oil pressure. On the other hand, there is the problem of protecting the internal combustion engine, in particular the lubricating oil in this heating from overheating. Therefore, additional high performance oil coolers are used. The known solutions are very complex and only lead to a relatively small reduction in fuel consumption, so that for economic reasons, the practical implementation is usually not realized.

The use of exhaust / oil heat exchanger, which directly heat the lubricating oil, has the disadvantage that in case of leaks in the heat exchanger oil can escape from the heat exchanger and flow on the hot exhaust or even splash, where it would then inflame.

Another disadvantage is that at high driving loads, ie high torques or tensile or compressive forces, when the oil has already reached its permissible limit temperature, heat is still transferred from the exhaust gas to the oil, even if the exhaust gas at high loads by means of a Damper or valve is bypassed past the exhaust / oil heat exchanger. The extra heat must be dissipated, for example, by a generously designed radiator, or by an oil cooler. Even without exhaust / oil heat exchangers such oil coolers are often used in the lubricating oil system of internal combustion engines with high power density, on the pressure side after the oil pump between the oil filter and engine block. The oil pressure at this point can be some bar, especially in cold start or at high speeds. Intended oil coolers are usually below arranged the exhaust manifold, so that in case of leakage no oil can drip on the exhaust. In addition, the thermal stresses in such oil coolers are limited because the temperature difference between the oil and the cooling water is relatively small and often does not exceed 20 ° C difference.

A disadvantage of such oil coolers is that they cool the oil even when it is not yet warm, so that the friction in the oil increases for a long time, and thus the fuel consumption.

In an exhaust gas / oil heat exchanger, however, the loads are much greater than with an oil cooler, since the temperature differences between the two media oil and exhaust gas can be up to 900 ° C. In addition, the risk of corrosion is many times greater, since the cooling condenses the water in the exhaust gas and forms together with other exhaust gas components aggressive and corrosive acids. Another problem is the possible freezing of the condensate after shutdown of the internal combustion engine at ambient temperatures below freezing, which could result in bursting of the heat exchanger.

In internal combustion engines without exhaust / oil heat exchanger so far passed for checking the oil pressure from a simple pressure switch, which indicates when the pressure falls below a limit this the driver with a warning light in the dashboard, so that the driver, for example. Can refill oil. However, modern oil lubrication systems with varying pressure ratios and a variety of means for improving oil lubrication, especially in startup phases suffer from the aforementioned problems, so that a more precise leakage control to protect the internal combustion engine at varying operating conditions is required.

The EP2 157 293 A1 shows an oil pressure monitoring method and a related device that can be used for a vehicle with automatic start-stop. In this case, when the automatic start-stop system is activated, an oil pressure warning typically lights up unless the start-stop status of the vehicle is monitored. It is proposed that monitoring of the oil pressure only takes place when the internal combustion engine is in operation. To detect the start-stop status, on the one hand the oil pressure is measured and on the other hand an activation of the automatic start-stop system is taken into account, whereby a value of the oil temperature is disregarded. However, no different oil pressure limits are taken into account, Furthermore, no leakage detection is considered in different operating situations of a system to be lubricated, but only an activation / deactivation of a known leakage detection device proposed for use in a start / stop mechanism, thus can be achieved by this teaching no improved leakage detection.

In addition, in the DE 10 2004 021 394 A1 a method and an apparatus for monitoring oil level, in which an oil meter determines the filling level of the lubricating oil in an oil reservoir and warns when it falls below or disables the internal combustion engine. The method only monitors the oil level and ignores other parameters.

In the WO 2010/106 179 A1 a complex oil lubrication system for accelerated heating of an engine or transmission is described, wherein a portion of an oil volume flow is passed through a bypass line in a cold start phase by fast heating system parts, so that the lubricating oil receives a high lubricity.

The DE 600 24776 T2 indicates the use of butterfly valves in conjunction with a turbocharger and exhaust gas recirculation system, whereby improved exhaust gas recirculation can be achieved.

The US 4,328,480 B relates to a leakage detection device of a vehicle in which an alarm signal is output by means of signals of an oil pressure sensor and an engine speed sensor when, with respect to a predetermined engine speed, an oil pressure does not reach a predetermined minimum pressure.

Finally, the reveals US 5 987 975 B a generic type detection device in which a lubricant flow rate sensor, a lubricant temperature sensor and a lubricant pressure sensor monitor the state of the lubrication system. A quotient of the volume flow as a function of the lubricant temperature by means of lubricant pressure is monitored, and in the event of a deviation of the Quotient can be concluded on a leakage or failure of the lubrication system.

The invention has for its object to improve an internal combustion engine or a transmission, in particular automatic transmission of the type mentioned with simple means to the effect that to minimize the risk of oil leakage a method for safe oil leakage at varying operating conditions is proposed.

Furthermore, the invention has for its object to propose the arrangement of an oil / heat exchanger, achieved by the improved engine lubrication even with a cold engine, in case of leakage, the failure of the lubrication can be reliably detected at varying operating conditions.

DISCLOSURE OF THE INVENTION

According to the invention the object is achieved by a method for leak detection of a lubrication system for the lubrication of rotating or oscillating components of an internal combustion engine or a transmission, preferably automatic transmission of a vehicle, by the leakage of the lubrication system by comparing an oil pressure of the lubrication system with a predeterminable pressure limit from a table or map for various of speed, torque and oil temperature, and at least one of the other parameters oil pump speed, valve position of an oil pump volume flow control, vehicle acceleration, Fahrzeugquerbeschleunigung and / or lubricating oil level is detected, when falling below a first limit pressure, a warning signal is output and / or falls below a second, lower limit pressure, the speed of the internal combustion engine is limited and / or falls below a third, even lower limit pressure the Verbrennungskra is switched off. Typical differential pressures between the first and second limiting pressures and between the second and third limiting pressures may be between 0.3 and 0.8 bar, in particular between 0.4 and 0.6 bar.

In other words, a leak detection method is proposed that determines the current oil pressure to monitor the oil lubrication system for leakage. The oil pressure is detected taking into account the currently available operating parameters speed, torque and oil temperature and one of the other parameters oil pump speed, valve position of an oil pump volume flow control, vehicle acceleration, vehicle lateral acceleration and / or lubricating oil level and compared with a readable from a table or map limit pressure or limit pressures and at Below the limit value, a warning is output, the drive speed is reduced and / or the internal combustion engine is switched off. The magnitude of the limit pressure or the limit pressures further depends on one of the further parameters valve position of an oil pump volume flow control, vehicle lateral acceleration and vehicle longitudinal acceleration and / or lubricating oil level. As a result, after the present driving situation or current operating situation of the internal combustion engine or the transmission, different limit values for detecting a leakage or a critical oil lubrication situation are taken into account, in particular with flexibly switchable Oil circuits, such as an oil circuit with oil bypass line for faster heating of the oil or at a connectable or disconnectable exhaust / oil heat exchanger or oil cooler different oil pressures in the detection of leakage can be considered.

The invention can be applied to all types of internal combustion engine driven equipment and vehicles such as cars, trucks, buses, motorcycles, construction machinery, ships, boats, aircraft and mobile and stationary Arbeitsgeräten- and devices, power plants such as emergency generators and the like. In particular, with short-term use and varying workloads, the invention enables optimum monitoring of lubrication to reduce friction between the moving parts, thus increasing the longevity of the machine, reducing the noise level, achieving higher efficiency, achieving higher power output, emitting lower exhaust emissions and costs can be saved. Furthermore, the leakage detection method of the lubrication system according to the invention can be used advantageously both in motor vehicles with automatic transmissions, as well as in motor vehicles with manual transmissions, and serve both for lubrication of the internal combustion engine and for lubrication of the gear unit.

In an advantageous refinement, it is proposed that an oil bypass line bypassing the oil return be connected to the suction line of an oil pump and the pressure line of a lubricating system, wherein the oil bypass line in the case of an internal combustion engine preferably by at least one cylinder head and / or cylinder block and / or at least one turbocharger and in the case of a transmission preferably by at least one heat exchanger of the internal combustion engine and / or at least one heating element runs, and that when falling below a certain limit temperature and exceeding a certain minimum pressure of the lubricating oil in the pressure line of the lubrication system, a bypass valve in the oil bypass line is at least partially opened, so that a partial flow of the lubricating oil in a warm-up phase of the lubrication system does not flow through the oil sump until either the minimum pressure or the limit temperature are reached. By returning the lubricating oil directly to the oil pump, the oil in the lubrication system heats up faster. Furthermore, the pressure loss to be overcome decreases Lubricating system, since the oil flowing back through the oil bypass line does not flow through the oil sump. Since the oil of the bypass line is preferably passed through the cylinder block and / or cylinder head, an increased oil volume flow at low temperatures can be achieved in an at least partial opening of the bypass valve, which can be arranged in or on the cylinder head or cylinder block, so that the oil more waste heat can record. As a result, a reduced friction is achieved in the warm-up phase, since the lubricating oil is led faster to operating temperature and the pressure losses are reduced. In this case, when connecting or disconnecting the bypass line, very different oil pressures prevail in the starting phase and in the warm phase in the internal combustion engine or the transmission, so that different oil pressure limits must be taken into account when the bypass line is switched on and off. In this case, it is advantageous to use at least the bypass valve position in the oil lubrication system to determine the limit pressure from a table or a characteristic diagram. Unlike simple lubrication systems, where it is usually sufficient to monitor the oil pressure, in such complex lubrication systems using exhaust gas / oil heat exchangers, there is a greater risk of leakage through the heat exchanger and the plurality of oil seals the variable lubrication circuits have different oil pressures that must be taken into account in leak detection.

In hybrid vehicles, which include both an internal combustion engine and an electric drive unit, the heating method by means of bypass line with improved leakage detection can be used for rapid heating of an electric motor / generator unit, which achieve optimum efficiency only at elevated temperatures, and also lubricate the electromotive moving components. In these cases, waste heat from the electrical energy storage unit (battery / battery) and / or the inverter can advantageously heat oil in the bypass line, thereby heating the electric motor / generator unit or lubricating it and a downstream transmission in an improved manner. In automatic transmissions, as well as in the internal combustion engine, an oil bypass line can be introduced, which contains a heat exchanger, through which additional heat is introduced into the transmission oil in the heating phase so as to reduce the friction.

According to an advantageous development of the leakage method with bypass line in the oil lubrication system, the oil bypass valve can be closed after completion of the warm-up phase and exceeding the limit temperature and / or the flow rate of the oil pump can be increased as soon as a given speed falls below a speed limit for given torque or torque of the components to be lubricated at a given speed a predetermined torque limit is exceeded in order to limit a decrease in the oil pressure within the oil line.

Completion of the warm-up phase is achieved as soon as the oil bypass valve is closed for the first time and the internal combustion engine or transmission has reached its operating temperature. The limit value for closing the bypass valve may be equal to the limit value for increasing the oil pump delivery rate, but may also be different. Also, the limit value for closing the bypass valve and / or the limit value for increasing the oil pump delivery rate may be hysteresis, with closure / opening of the bypass valve or raising / lowering of the oil pump delivery rate occurring only when the limit values are exceeded or exceeded. Since different oil pressures are required at different oil temperatures, loads (ie torques, compressive or tensile loads) and speeds to ensure adequate lubrication and to prevent damage to the components to be lubricated, the bypass valve in the oil bypass line can be closed as soon as a predetermined Speed at given torque falls below a speed limit or a torque of the components to be lubricated at a given speed exceeds a predetermined torque limit to limit a decrease in the oil pressure within the oil line. For this purpose, a speed / torque characteristic map can be used which define the speed or torque limit value, or specify areas of the 2D characteristic field as limit value ranges.

In order to further accelerate the warming up of the oil and to further reduce the pressure loss of the lubricating system, it is favorable if at least one of the lubricating oil return flows arranged downstream of the devices to be lubricated is connected to the oil bypass line, wherein one of the connected to the oil bypass line lubricating oil return is part of an exhaust gas turbocharger.

According to an advantageous development, an exhaust gas / oil heat exchanger can be arranged in an oil suction pipe between the oil pump and the oil sump, so that a negative pressure is established on the oil side in the exhaust gas heat exchanger compared to the environment and compared to the pressure in the exhaust system. Thus, lower component loads and thus a longer life of the heat exchanger can be achieved, as it is exposed to lower pressures, and oil leakage can be avoided.

In order to accelerate the heating of the lubricating oil in addition, it is advantageous if the heat exchanger for heating the lubricating oil is flowed through by the exhaust gas of an internal combustion engine downstream of a catalyst. In this case, the exhaust gas flowing through the heat exchanger can flow upstream through a first exhaust valve. This first exhaust valve can be closed as soon as a predetermined limit temperature of the exhaust gas is reached in order to avoid coking of the lubricating oil in the heat exchanger. Thus, in an advantageous development, the exhaust gas flowing through the exhaust / oil heat exchanger upstream through the first exhaust valve / exhaust gas recirculation valve, the first exhaust valve / exhaust gas recirculation valve can be closed as soon as a predetermined limit temperature of the exhaust gas or the lubricating oil is reached, and / or at least a portion of the exhaust gas is passed via a controllable second exhaust valve directly above or adjacent to the oil sump into or through an oil sump or into the bypass line to increase heat transfer. Thus, the exhaust gas flowing parallel to the heat exchanger of the internal combustion engine can flow through the second exhaust valve and the second exhaust valve can be at least partially closed at times to increase the exhaust gas flow and thus also the heat transfer in the heat exchanger. In this case too, it makes sense to orient the limit pressure (s) for determining the leak at the valve position of the exhaust valve position (s).

In an advantageous development, the exhaust gas flowing through the exhaust / oil heat exchanger can be passed through a further first exhaust gas recirculation valve and can thus downstream as exhaust gas recirculation with the intake manifold of a Be connected internal combustion engine, the further first exhaust gas recirculation valve may be at least partially closed as soon as a predetermined limit temperature of the exhaust gas is reached or a predetermined volume flow of the exhaust gas recirculation is achieved. In order to reduce the combustion temperature and thus also the nitrogen oxide emissions of the internal combustion engine, the exhaust gas flowing through the heat exchanger downstream flows through the further first exhaust gas recirculation valve in the intake manifold of an internal combustion engine, the further first exhaust gas recirculation valve is at least partially closed as soon as a predetermined limit temperature of the exhaust gas is reached or as soon as a predetermined volume flow of the exhaust gas recirculation is achieved. In this case, the exhaust gas is cooled by the exhaust / oil heat exchanger, which has a further reduction of the combustion temperature result, so that it can be dispensed with the use of an additional cooler for the exhaust gas recirculation. In this case as well, the limit pressure (s) of the leakage detection advantageously varies as a function of the position of the exhaust gas recirculation valve, so that the valve position of the exhaust gas recirculation valve should be taken into account when determining the limit pressure (s).

In an advantageous development, the exhaust gas flowing parallel to the exhaust / oil heat exchanger of the internal combustion engine can be passed through a third exhaust valve and the third exhaust valve can be at least partially closed at times to increase the exhaust gas flow and thus the heat transfer in the exhaust / oil heat exchanger. The second and the third exhaust valves may be identical, but also be two different exhaust valves. Thus, the second exhaust valve may switch a partial flow of the exhaust gas flowing through the exhaust gas / oil heat exchanger while the third exhaust valve switches an exhaust gas partial flow flowing parallel to the exhaust gas / oil heat exchanger. Also in this embodiment, the limit pressure (s) for the leakage detection advantageously varies depending on the position of the third exhaust valve, so that the valve position of the exhaust gas recirculation valve should be taken into account in determining the limit pressure (s).

In an advantageous development, an additional heat exchanger and a first oil valve is arranged downstream of the oil pump for cooling, wherein the first oil valve is at least partially opened when a predetermined limit value for the lubricating oil temperature is exceeded or exceeded or a predetermined limit value for the coolant inlet temperature or the coolant outlet temperature is exceeded, preferably in the lubricating oil line parallel to the heat exchanger and valve, a second oil valve can be arranged, and the second oil valve is at least partially closed when a predetermined limit value for the lubricating oil temperature is exceeded or undershot. The heat exchanger is flowed through by a cooling medium such as ambient air or coolant to cool the lubricating oil. In another variant, this heat exchanger is flowed through by the exhaust gas of the internal combustion engine in order to heat the lubricating oil and reduce the friction. It is advantageous if a second valve is arranged in the lubricating oil line parallel to the heat exchanger and the first valve. This valve can be at least partially closed when a predetermined limit value for the lubricating oil temperature is exceeded or undershot. It is expedient in this case also if this heat exchanger is arranged in the circuit for cabin heating or in the circuit for heating or cooling of an electric battery.

Convenient in the context of the invention in the arrangement of a bypass line, it may be if the length of the oil line of the lubrication system from the output of the oil pump to the entry into the oil bypass line at least 80% of the maximum length of the oil line of the lubrication system from the output of the oil pump to weitest removed to be lubricated device. As a result, the lubricating oil flowing through the oil bypass line can heat better. It is particularly advantageous if the lubricating oil mass flow through the oil bypass line is at least temporarily greater than the lubricating oil mass flow through the oil suction pipe and the oil sump. In this case, the total mass flow flowing through the lubricating system is heated faster than without oil bypass line. However, it is also conceivable that, since the Ölsaugrohrkonfiguration is modifiable at a subsequent retrofitting only at great expense, provide a branch to the bypass on the intake of the Ölsaugrohrs, so that practically the mass flow of the bypass line also flows through the Ölsaugrohr. Due to the length of the oil bypass line results in a pressure difference, which can be safely taken into account in the leak detection by changing the limit pressure / limit pressures.

Thus, in a known lubrication system with bypass line and leakage detection, the oil bypass line is connected to the suction line of the oil pump and the lubricating oil mass flow through the oil bypass line is at least temporarily greater than the lubricating oil mass flow through the oil suction pipe. This has the disadvantage that it is very difficult to retrofit such an oil bypass line in a used vehicle, since you have to disassemble the oil pan and the oil suction, which can be very expensive. Therefore, it may be advantageous if the end of the oil bypass line opens into the intake of the Ölsaugrohres without connecting it directly to the Ölsaugrohr. This has the advantage that the oil bypass line can be inserted through a simple hole in the oil pan in the opening of the suction of the Ölsaugrohres, and so disassembly of the oil pan and the Ölsaugrohres can be avoided. Since the end of the oil bypass line is in the immediate vicinity of the Ölsaugrohreinlasses, thereby most of the oil mass flow of the oil bypass line will be sucked by the Ölsaugrohr. As a result, the pressure loss in the suction pipe of the oil suction pipe can even be reduced.

It may be expedient if the oil bypass line is arranged in the same housing, in which at least one of the devices to be lubricated are arranged, so that the back-flowing lubricating oil can additionally heat and in the event of leakage, the oil can be collected in the housing. It is particularly advantageous if one or more of the oil returns are connected directly to the suction line of an oil pump.

It may also be advantageous in the context of the invention if the oil bypass line consists of a heat-insulating material with a thermal conductivity of less than 1 W / (m * K), in order to reduce the heat transfer to the environment during the backflow, especially where the Oil bypass line is not passed through the device to be lubricated.

For controlling oil pressure and oil temperature, it is favorable in the context of the invention, when a control unit can control the opening cross section of the various valves, and if sensors for detecting the lubricating oil pressure, the lubricating oil temperature, the exhaust gas temperature, the rotational speed, the torque, the oil level, the Pump speed, the vehicle speed, longitudinal and / or - lateral acceleration and / or the coolant temperature are connected to the control unit. The control unit can favorably process the sensor data for evaluation of the leak detection or provide the sensor measured values for this purpose.

Favorable for the purposes of the invention is also when at least a part of the lubrication system is arranged in a transmission which is connected to the internal combustion engine and the internal combustion engine and the transmission are part of a motor vehicle. It is particularly advantageous if the exhaust / oil heat exchanger is designed to double flow on the oil side, so that the transmission oil and the lubricating oil can be heated simultaneously in parallel and the exhaust gas heat exchanger is connected to the exhaust pipe by a heat insulating material which has a heat conductivity less than 1 W. / (m * K). Thus, a single exhaust / oil heat exchanger can be provided, thus minimizing the risk of leakage of the heat exchanger.

The sealing of the valves in the exhaust pipe has a particularly important importance in improving the leakage resistance, since a high density on the one hand improves the effectiveness of the heating and on the other hand in the closed position avoids that the oil heats up unintentionally, for example, at high driving loads and speeds. This eliminates the need for an additional oil cooler, so that leakage in the oil cooler can be avoided. As a result, it proves advantageous for the purposes of the invention if the valves in the exhaust pipe can be integrally formed as a three-way valve and that these valves can be designed as a double-acting poppet valve, wherein the plate has two sealing surfaces. Of these, a sealing surface is disposed at the extreme end of the valve, as in an exhaust valve in the cylinder head of an internal combustion engine. The second sealing surface is arranged on the opposite side of the valve disk, from which the valve stem leads away from the actuator. In the active state, the outermost end of the valve closes the exhaust gas bypass and in the passive state, the inner sealing surface of the plate closes the line to the heat exchanger.

In a sidelined aspect, an apparatus for leak detection of a lubrication system of rotating or oscillating components for an internal combustion engine or a transmission, preferably automatic transmission for performing an aforementioned method is proposed. For this purpose, an exhaust / oil heat exchanger is arranged in an oil suction between oil pump and oil sump, on the oil side in the exhaust / oil heat exchanger, a negative pressure compared to the environment and compared to the pressure in the exhaust system is adjustable, so that in case of leakage, an oil leakage is excluded from the exhaust / oil heat exchanger. Thus, in the event of leakage, no oil can pass from the oil lubrication system into the exhaust stream or into the environment. By monitoring the pressure conditions in the lubrication system, a warning can be issued in the event of an oil spill, the speed is reduced and / or the internal combustion engine or the drive are turned off. One aspect is a reduction in fuel consumption of up to 7%, with leakage of the lubrication system through the heat exchanger without consequences, since it is operated on the negative pressure side of the oil pump, so that oil does not escape in the event of leakage. The advantage is that, in the event of a leak, no oil can escape from the exhaust / oil heat exchanger and drip onto the hot exhaust where the oil could ignite. Thus, the risk of leakage is significantly reduced, saving fuel and a leak detected quickly and situation-dependent, so that damage to the internal combustion engine or transmission can be effectively prevented.

In this case, parallel to the exhaust gas / oil heat exchanger in a the exhaust gas / oil heat exchanger bypassing exhaust gas bypass line, a third exhaust valve may be arranged to increase the exhaust gas flow and thus the heat transfer in the exhaust / oil heat exchanger, at least temporarily. By switching the third exhaust valve, the heat exchange of the exhaust gas / oil heat exchanger can be controlled very effectively.

To reduce exhaust emissions in the warm-up phase, methods are known from the prior art in which ambient air is blown by means of a fan by pressure in the exhaust system upstream of the catalyst in the exhaust ports to oxidize fuel residues and warm up the catalyst faster. The disadvantage here is that these blowers are operated only within a few seconds after the engine start and then not be used until the internal combustion engine is cooled again. According to an advantageous Further, the heat exchanger may comprise an air blower which pumps cooling air through the heat exchanger into the exhaust gas line, in particular when an exhaust gas bypass is open. In this case, exhaust gas can be passed through the exhaust gas bypass when opening the second or third exhaust valve. By arranging an independent air blower in the heat exchanger, a variable cooling and heating of the lubricating system and the use of the heat exchanger can be achieved as an oil cooler, largely independent of the exhaust gas temperature and the possibility of fresh air entry into the exhaust system. The limits for detecting the leakage can be adjusted according to the switching position of the exhaust valves.

For bypass control of exhaust gas heat exchangers 3-way valves are known, which either reduce or minimize the exhaust gas mass flow through the exhaust gas heat exchanger and increase or maximize the exhaust gas mass flow through the bypass, or increase or maximize the exhaust gas mass flow through the exhaust gas heat exchanger while the exhaust gas mass flow through reduce or minimize the bypass. An intermediate position is often possible. A disadvantage of these 3-way flaps is that the flaps cause relatively large leaks in the closed line, so that, for example closed bypass a Teilabgasstrom does not flow through the heat exchanger, and so its heat can not be used, or continue with a closed exhaust gas heat exchanger through a partial exhaust gas the heat exchanger flows, and so on heat is transferred to the second medium, which can either lead to overheating of the second medium, or it must be another cooler used for cooling the second medium. Another disadvantage is that only the supply line to the exhaust gas heat exchanger is closed. The derivative of the exhaust gas heat exchanger is connected directly to the end of the bypass line, so that it comes here to the backflow of hot exhaust gas in the exhaust gas heat exchanger, which is also very unfavorable in closed heat exchanger. If, for the purpose of cooling the second medium, air is blown into the heat exchanger with the aid of a blower, the backpressure in the exhaust must be overcome, which at full load can be, for example, 0.3 bar. As a result, the required power consumption of the cooling air blower increases significantly, and the back pressure in the exhaust gas increases, whereby the maximum drive power and torque are reduced and the efficiency of the drive is reduced. Another disadvantage of the known three-way valves is that they are at least partially opposed have to be arranged to the flow through the exhaust gas, which also increases the exhaust back pressure with open bypass.

According to an advantageous development, a butterfly valve for actuating the exhaust gas bypass may be included, which completely isolates the exhaust gas / oil heat exchanger from the exhaust gas line in the heat exchanger bypass mode. Thus, the second and / or third exhaust valve may be designed as a butterfly valve. Additionally or alternatively, a fourth exhaust valve is arranged on the other side of the exhaust / oil heat exchanger, wherein the fourth exhaust valve opens automatically as a pressure relief valve automatically to the environment, when the exhaust / oil heat exchanger is separated by the butterfly valve from the exhaust system and the fan active or the fourth exhaust valve is opened upon activation of the blower, whereby an increase of an exhaust gas back pressure is avoided. This may be independent of whether a blower is used and on which side of the exhaust gas / oil heat exchanger the blower is located. Butterfly valves work comparable to ball valves, wherein a flat circular disc is rotatably arranged in the center of a tube, wherein the axis of rotation is rotatable from the outside by an actuator in a supply and installation. The blocking element causes a pressure loss in the butterfly valve. However, if a butterfly valve is mounted in the sidewall of a pipeline, 4-way regulation can be easily achieved. That is, when the butterfly valve is closed, both the supply and the discharge of the exhaust gas heat exchanger is closed, so that its backflow is avoided by hot exhaust gas. If the butterfly valve attached to the side wall of the exhaust gas line, so that when the exhaust / oil heat exchanger one half of the butterfly valve completely closes the exhaust pipe and also closes a second bypass between exhaust pipe and exhaust / oil heat exchanger, and at the same time the supply and discharge of the Exhaust / oil heat exchanger completely opens. The arrangement of the butterfly valve in the side wall of the exhaust pipe, the exhaust back pressure is not increased with closed exhaust / oil heat exchanger. Another advantage of this arrangement is that even when the exhaust gas heat exchanger is closed, the leakage flow through the exhaust / oil heat exchanger is reduced because the flap in the front region of the flap, which seals the supply line to the heat exchanger, is pressed against the sealing surfaces by the exhaust gas back pressure. When the exhaust / oil heat exchanger is closed, there is another advantage in that the Äbgas- / oil heat exchanger through parts of the inlet and outlet lines and through the open in this case internal bypass between the exhaust / oil heat exchanger and exhaust pipe by the non-flowing in this intermediate gap Gas is isolated, and so no further heat to the second medium (oil) is supplied. Due to the high sealing effect of the butterfly valve, the exhaust / oil heat exchanger can thus also be used as an oil cooler, since the cooling air blower does not have to overcome the exhaust back pressure and the cooling air can flow back through the exhaust / oil heat exchanger directly through a fourth valve to the environment without increasing the exhaust backpressure.

• bei einer Verbrennungskraftmaschine durch zumindest einen Zylinderkopf und/oder zumindest einen Turbolader, oder;
• bei einem Getriebe bevorzugt durch zumindest einen Wärmetauscher der Verbrennungskraftmaschine und/oder zumindest ein Heizelement verläuft;

und dass zumindest ein Teilstrom des Schmieröls zumindest in einer Warmlaufphase des Schmiersystems nicht durch den Ölsumpf strömt, bis entweder ein Grenzöldruck oder eine Grenzöltemperatur erreicht wird.In a further development of the lubricating device with leakage detection, the oil suction tube may be connected to an oil bypass line bypassing the oil return, wherein a bypass valve is disposed in the oil bypass line, and the oil bypass line and / or at least one of the oil return is connected to the suction line of an oil pump and the pressure line of a lubrication system , and the oil bypass line

• in an internal combustion engine by at least one cylinder head and / or at least one turbocharger, or;
• in a transmission preferably by at least one heat exchanger of the internal combustion engine and / or at least one heating element extends;

and that at least a partial flow of the lubricating oil does not flow through the oil sump at least in a warm-up phase of the lubrication system until either a limit oil pressure or a limit oil temperature is reached.

In the aforementioned by-pass lubricating apparatus, further, the oil bypass passage and / or at least one of the oil returns may be connected to the exhaust gas / oil heat exchanger or another heat exchanger, and the heat exchanger for heating the lubricating oil may be disposed downstream of the catalyst in the exhaust system of an internal combustion engine and upstream of the heat exchanger, a first exhaust gas / exhaust gas recirculation valve may be arranged, which varies the flow in dependence on at least the oil temperature or the exhaust gas temperature, preferably downstream of the heat exchanger, a further first exhaust gas recirculation valve is arranged and the further first exhaust gas recirculation valve downstream is connected to the intake manifold of an internal combustion engine.

If in the lubrication system an oil return umführführende oil bypass line is connected to the suction of an oil pump and the pressure line of a lubrication system, advantageously a control of the volume flow of the arranged in the oil circuit oil pump can be made, which is independent of the speed of the internal combustion engine or the transmission the volume flow of the oil pump is increased when the bypass valve is open and reduced when the bypass valve is closed. Thus, in contrast to the prior art, it is proposed to increase the volume flow in the cold start, instead of reducing it normally. By returning the lubricating oil directly to the oil pump, the oil in the lubrication system heats up faster. Furthermore, the pressure loss of the lubrication system to be overcome decreases since the oil flowing back through the oil bypass line does not flow through the oil sump. Since the oil of the bypass line is preferably passed through the cylinder block and / or cylinder head, an increased oil volume flow at low temperatures can be achieved in an at least partial opening of the bypass valve, which can be arranged in or on the cylinder head or cylinder block, so that the oil more waste heat can record. The leakage detection can take into account the valve positions that change depending on the operating phase and correspondingly changed oil pressure ratios by taking into account parameters such as valve positions, rotational speed, etc. As a result, a reduced friction is achieved in the warm-up phase, since the lubricating oil is led faster to operating temperature and the pressure losses are reduced. Furthermore, an increase in the volume flow is achieved during the cold start phase, so that efficient oil lubrication can be achieved, in particular during the cold start phase. Variable controllable oil pumps are a known measure for reducing fuel consumption in internal combustion engines. In non-controllable oil pumps, the oil pressure increases more or less linearly with the increase of the drive speed. Even at very low temperatures, the oil pressure increases due to the increase in oil viscosity compared to the warm engine. In order to avoid leaks due to excessive oil pressures, a pressure relief valve is usually used that opens a bypass line when a limit pressure is exceeded. As a result, the oil pressure increases less with increasing speed. With variable Oil pumps either the oil pressure of the oil pump by further adjustment or control devices further limited, so that, for example, the oil pressure from a certain limit stops increasing. This reduces the power consumption of the oil pump. How out Will, F., Boretti, A.,: "A New Method to Warm Up Lubricating Oil to Improve Fuel Economy", SAE 2011-01-0318, 2011 However, variable oil pumps have the disadvantage that the heat transfer from the oil galleries to the lubricating oil is reduced by the reduced pressure and the reduced volume flow. For this reason, a control of the oil pump volume flow is proposed depending on the position of the bypass valve and regardless of the drive speed to overcome this disadvantage.

It is further conceivable to provide an additional bypass adjacent the main bypass of main oil gallery to the cylinder head, wherein preferably the additional bypass line comprises an additional bypass valve which closes when the main bypass valve is closed, and in particular the bypass valve and the additional bypass valve via the same oil bypass -Ventilaktuator are actuated. As a result, improved heating of the reduced amount of lubricating oil can be achieved by guiding the oil flow through rapidly heating regions of the cylinder head and thus improved lubrication. In many internal combustion engines, the oil flow rate is limited by the cylinder head, for example by throttling on the cylinder head gasket, or by additional throttle valves. For example, the oil supply line from the engine block to the cylinder head may have a diameter of 10mm, however, the transition of this line through the cylinder head gasket may be limited to 3mm. This ensures that the oil pressure in the cylinder head is lower than in the engine block, so that damage to sensitive hydraulic valve lifters are avoided. The disadvantage of such throttle points is that it also reduces the volume flow in the cylinder head and thus also the heat transfer from the cylinder head to the lubricating oil is reduced, causing the oil to warm up more slowly, which increases fuel consumption. These disadvantages can be overcome by the additional bypass to increase the flow and heat transfer in the cylinder head. The additional bypass also has the advantage that no intervening changes are required within the internal combustion engine, since normally the oil flow through the cylinder head gasket is throttled, you need So not to change the head gasket. It is conceivable to retrofit this additional bypass as part of a subsequent conversion of an existing lubrication system in order to achieve its advantages. The conversion can be made without intervening changes in the internal combustion engine, since in most cases, the flow of oil through the cylinder head gasket is throttled, one does not need to change the head gasket.

DRAWINGS

Further advantages result from the present description of the drawing. In the drawing, various lubrication systems are shown as a description of the background of the invention. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

ein Schaltbild eines ersten Schmiersystems einer Verbrennungskraftmaschine;

Fig. 2

ein Schaltbild eines zweiten Schmiersystems in einer Verbrennungskraftmaschine;

Fig. 3

ein Schaltbild eines weiteren Schmiersystems in einem kalten Zustand;

Fig. 4

ein Schaltbild des Systems der Fig. 3 in einem warmen Zustand;

Fig. 5

ein Schaltbild eines Schmiersystems in einem Automatikgetriebe;

Fig. 6

ein Schaltbild eines Ausführungsbeispiels eines Schmiersystems.

Show it:

Fig. 1

a circuit diagram of a first lubrication system of an internal combustion engine;

Fig. 2

a circuit diagram of a second lubrication system in an internal combustion engine;

Fig. 3

a circuit diagram of another lubrication system in a cold state;

Fig. 4

a schematic diagram of the system Fig. 3 in a warm state;

Fig. 5

a circuit diagram of a lubrication system in an automatic transmission;

Fig. 6

a circuit diagram of an embodiment of a lubrication system.

In the different figures, the same parts are always provided with the same reference numerals, so that they are usually described only once.

FIG. 1 shows an internal combustion engine 30 in a schematic diagram. The internal combustion engine 30 has an exhaust pipe 14, in which a catalyst 10 is arranged. In the illustrated lubrication system, the internal combustion engine 30 is shown as a four-cylinder engine, the four cylinder manifolds open into a common exhaust pipe 14.

When viewed in the exhaust gas flow direction of the exhaust gas, an exhaust gas / oil heat exchanger 8 is arranged in the exhaust gas line 14 behind the catalytic converter 10, and a turbocharger 24 is arranged in front of the catalytic converter. The internal combustion engine 30 has a lubricating oil system 16. The lubricating oil system 16 comprises an oil sump 1, an oil receiving line 2, an oil pump 3, devices 31 to be lubricated of a cylinder head 12 and a cylinder block 15 and a turbocharger 24, an oil pan 5, and an oil pressure relief valve 4.

The lubricating oil system 16 is also assigned a bypass valve 17. The bypass valve 17 controls the flow of the lubricating oil through the lubricating oil bypass 23, so that the temperature and the pressure of the lubricating oil can be set at optimum values. Furthermore, the lubricating oil system 16 has a plurality of oil returns 19.

The exhaust / oil heat exchanger 8, at least upstream of the exhaust stream, an exhaust gas or exhaust gas recirculation valve 20, 21, 41, advantageously an exhaust gas recirculation - control valve (EGR control valve) upstream, which regulates the exhaust gas flow through the exhaust / oil heat exchanger 8 and thus indirectly the oil temperature regulates. The exhaust gas / oil heat exchanger 8 is integrated in the lubricating oil system 16, so that the oil is heated in a warm-up phase of the internal combustion engine 30 by means of the exhaust gas heat. As an alternative to an exhaust gas / oil heat exchanger 8, one or more electrical heating elements, in particular heating rods, can be used, which also fulfill the purpose of heating the oil within the bypass line. In particular, when used in an automatic transmission, it makes sense to use an exhaust / oil heat exchanger for heating the oil in the bypass line. In the illustrated lubrication system, a third exhaust valve 13 is additionally arranged in the exhaust pipe 14 parallel to the exhaust / oil heat exchanger 8, which regulates the exhaust gas flow through the exhaust gas bypass 38 bypassing the exhaust gas / oil heat exchanger 8.

In the lubricating oil system 16 downstream of the oil pump 3, a first oil valve 29 and a heat exchanger 26 are arranged with a supply line 27 and a discharge line 28 for controlling the oil temperature and the oil pressure. In a further oil bypass bypassing the heat exchanger 26, a second oil valve 25 for regulating the oil pressure and the oil temperature is furthermore arranged. The heat exchanger 26 can serve as an oil cooler for heating a cabin interior of a vehicle.

For controlling oil pressure and oil temperature, a control unit 18 is connected to the valves 13, 17, 20, 21, 25, 29 and 41, and sensors for detecting the lubricating oil pressure 32, the lubricating oil temperature 33, the exhaust gas temperature 34, the rotational speed 35, the torque Last 36 and the coolant temperature 37 are connected to the control unit 18. The data of the sensors can be processed or made available by the control unit for leakage detection.

In the intake system 6 of the internal combustion engine 30, a throttle valve 7 is arranged, which is connected to a turbocharger 24, which opens downstream into an intake manifold 9. To reduce the combustion temperature of the intake manifold is connected via a further first exhaust gas recirculation valve 21, which may be configured as EGR control valve, with the exhaust pipe 14 for exhaust gas recirculation, wherein the connection downstream of the exhaust / oil heat exchanger 8 is arranged. In this case, the exhaust gas / oil heat exchanger 8 may be an EGR heat exchanger. In this way harmful nitric oxide emissions are reduced.

By the in FIG. 1 advantageous embodiment, the lubricating oil is heated faster 30 in a warm-up phase of the internal combustion engine. Parallel to the exhaust / oil heat exchanger 8 controlled via the third exhaust valve 13 exhaust bypass 38 is guided so that prevents overheating of the lubricating oil in the heat exchanger becomes. The exhaust / oil heat exchanger 8 is preferably sufficiently dimensioned in the countercurrent principle, so that the lubricating oil is heated as quickly as possible, wherein the exhaust gas is cooled down as much as possible.

FIG. 2 shows another lubrication system. In contrast to FIG. 1 the exhaust outlet of the exhaust / oil heat exchanger 8 is connected only to the intake manifold 9, so that the third exhaust valve 13 and the exhaust gas recirculation valve 20 are not required.

In this lubrication system, the exhaust / oil heat exchanger 8 has a double function. On the one hand, the exhaust / oil heat exchanger 8 heats up the lubricating oil during the warm-up phase due to the exhaust gas temperature. On the other hand, in order to avoid high combustion temperatures, the exhaust gas / oil heat exchanger 8 acts as a cooler of the exhaust gas recirculation 22 by cooling the exhaust gas recirculated into the intake manifold 9 by the lubricating oil. This can be dispensed with an additional cooler for exhaust gas recirculation and additional valves to control the exhaust gas flow rate.

• Der Hauptölfluss durch das Bypassventil 17 ist durch eine fett dargestellte Linienverbindung gekennzeichnet: Das Öl strömt aus dem Zylinderkopf 12 in den Turbolader 24. Von dem Turbolader 24 führt eine Ölbypassleitung zu dem geöffneten Bypassventil 17 durch die das Öl weiterströmt und mit der Ölrückführungsleitung 19 aus dem Turbolader 24 zusammengeführt wird. Von dort fließt das Öl weiter durch den Abgas-/Ölwärmetauscher 8, in dem es vom heißen Abgas erwärmt wird. Danach wird das Öl durch die Ölwanne 1 zurückgeführt wo die Rückführleitung 23 mit dem Ölansaugrohr 2 verbunden ist, so dass das erwärmte Öl direkt weiter von der Ölpumpe 3 angesaugt werden kann.

FIG. 3 shows a lubrication system of an oil lubrication device in a cold state, eg shortly after starting a motor vehicle:

• The main oil flow through the bypass valve 17 is characterized by a bold line connection: The oil flows from the cylinder head 12 into the turbocharger 24. From the turbocharger 24 an oil bypass line leads to the open bypass valve 17 through which the oil continues to flow and with the oil return line 19 from the Turbocharger 24 is merged. From there, the oil continues to flow through the exhaust / oil heat exchanger 8, where it is heated by the hot exhaust gas. Thereafter, the oil is returned through the oil pan 1 where the return line 23 is connected to the Ölansaugrohr 2, so that the heated oil can be sucked directly further from the oil pump 3.

The flow of exhaust gas through the exhaust gas / oil heat exchanger 8 is also represented by a bold line connection: the hot exhaust gas flows from the catalyst 10 into the exhaust conduit 14 and thence through the opened exhaust gas recirculation valve 21 into the exhaust / oil heat exchanger 8 where it flows warmed up with cold oil Cools exhaust gas while doing so. From there, the cold exhaust gas flows through the exhaust gas recirculation line 22 back into the intake manifold 9. Once a certain limit value for the oil pressure is exceeded, the oil bypass valve 17 is completely or at least partially closed, so that the oil pressure in the internal combustion engine 30 may rise again. The oil bypass valve 17 is also completely or at least partially closed when exceeding a maximum oil temperature, while then the other first exhaust gas recirculation valve 21 is closed or alternatively the in Fig. 4 shown EGR bypass flap 39, which is used as a third exhaust valve 13, opened.

• Das Bypassventil 17 ist ganz oder zumindest teilweise geschlossen, so dass nur ein sehr kleiner Ölvolumenstrom durch den Abgas-/Ölwärmetauscher 8 fließt. Der überwiegende Teil des Schmieröls - hier als fette Linie gezeigt - fließt durch die Lagerstellen 31, z.B. Kurbelwellenhauptlager, Pleuellager, Nockenwellenlager, Kolbenspritzdüsen, Nockenwellenversteller, Nockenwellenstößel, etc. entweder durch Rückführungsleitungen 19 oder direkt zurück in die Ölwanne 1. Das weitere erste Abgasrückführungsventil 21 kann entweder geschlossen oder geöffnet sein. Falls das weitere erste Abgasrückführungsventil 21 geöffnet ist, ist es von Vorteil, wenn das Abgas über eine weitere AGR-Bypassklappe 39 als drittes Abgasventil 13 in die Abgasrückführungsleitung 22 und den Ansaugkrümmer 9 zurück geführt wird, wobei der Abgas-/Ölwärmetauscher 8 vom Abgasstrom abgekoppelt wird.

FIG. 4 shows the system in a simplified version when warm:

• The bypass valve 17 is completely or at least partially closed, so that only a very small volume of oil flow through the exhaust / oil heat exchanger 8 flows. The majority of the lubricating oil - shown here as a bold line - flows through the bearings 31, eg crankshaft main bearings, connecting rod bearings, camshaft bearings, piston injectors, camshaft adjuster, camshaft plunger, etc. either through return lines 19 or directly back into the oil pan 1. The other first exhaust gas recirculation valve 21st can be either closed or open. If the further first exhaust gas recirculation valve 21 is opened, it is advantageous if the exhaust gas via a further EGR bypass valve 39 as the third exhaust valve 13 in the exhaust gas recirculation line 22 and the intake manifold 9 is guided back, wherein the exhaust / oil heat exchanger 8 decoupled from the exhaust stream becomes.

• Das Abgas strömt von einer Verbrennungskraftmaschine 30 (nicht dargestellt) durch einen Katalysator 10 in ein 3-Wegeventil 41. Im kalten Zustand strömt das Abgas durch einen Abgas-/Ölwärmetauscher 8 und erwärmt das Getriebeöl, welches durch ein Ölbypassventil 17 freigegeben wird. Im warmen Zustand fließt das Abgas nicht durch den Abgas-/Ölwärmetauscher 8 sondern durch den Ölbypass 38 und das Bypassventil 17 ist ganz oder zumindest teilweise geschlossen.

FIG. 5 shows the system in combination with an automatic transmission 40:

• The exhaust gas flows from an internal combustion engine 30 (not shown) through a catalyst 10 into a 3-way valve 41. In the cold state, the exhaust gas flows through an exhaust gas / oil heat exchanger 8 and heats the transmission oil, which is released by an oil bypass valve 17. In the warm state, the exhaust gas does not flow through the exhaust / oil heat exchanger 8 but through the oil bypass 38 and the bypass valve 17 is completely or at least partially closed.

With increasing oil pressure, the volume flow of the oil pump 3 decreases more or less linear, this occurs especially at low oil temperatures. As the volumetric flow decreases, however, the heat transfer coefficient between the oil and the cylinder head decreases 12 or cylinder block 15, so that the oil can absorb only a little heat from the cylinder head 12 and cylinder block 15. At very high pressures, an oil pressure relief valve 4 opens, with the oil flowing back into the oil sump 1. As a result, the oil volume flow flowing through the cylinder head 12 and block 15 decreases, so that the mechanical pumping power of the oil pump 3 is reduced. This reduces the heat transfer coefficient between oil and metal of the cylinder block 15 or head 12.

An increase in the heat transfer coefficient at low temperatures can be achieved by such a lubrication system 16 in that the volume flow through the cylinder block 15 and in particular through the cylinder head 12 is increased at low temperatures. This is achieved by at least partial opening of the oil bypass valve 17, for example as a function of oil temperature, oil pressure, drive speed and / or torque. Supporting this is also conceivable, the volume flow rate of the oil pump 3 to increase mechanically or by a manual transmission or increase by moving conveyor wheels.

Furthermore, it is conceivable to support the oil gallery in the cylinder head 12 in series rather than parallel, i. to flow in the counterflow principle of the oil. For this purpose, it may be advantageous first to let the oil flow flow through a main gallery of a cylinder head 12, then to flow back in the opposite direction at the outlet end by means of a reflux oil valve through a further main gallery of a cylinder head 12 so that the flow path of the oil through the cylinder head 12 is increased becomes. The reflux oil valve can also be arranged on the other side of the bypass line 23 in the oil pan.

The oil contained in the oil passages of an internal combustion engine 30 is only a fraction, usually only 10% of the total volume of oil. In the warm-up phase, the entire oil volume is uniformly heated in the method known from the prior art. One aspect is to achieve in the context of the improved leakage detection and prevention targeted rapid heating of the located in the oil channels lubricating oil, this by connecting the oil passage of the cylinder head or 12 by means of a bypass line 23 with the suction side of the

Oil pump 3 is reached, at the end of the bypass line 23, a negative pressure applied to the oil not to flow back into the oil sump 1 but back into the oil passage. Thus, in the warm-up phase of the internal combustion engine, only a small, quickly heated part of the total oil is used for lubrication.

The generation of a negative pressure at the end of the bypass line 23 can be achieved by direct connection of the bypass line 23 with the suction side of the oil pump 3 and with a direct connection to the oil suction pipe 2. For this purpose, the bypass line 23 can be at least partially integrated in a plastic oil pan 1 with integrated oil suction 2, which leads to improved insulation and less heat loss. Furthermore, the mouth of the bypass line 23 can be positioned in the oil sump 1 in close proximity to the opening of the Ölsaugrohres 2, so that the opening of the bypass line end in the direction of the opening of the Ölansaugrohres 2 shows and forms with this an angle of 0 to 45 °, thereby also facilitates installation and the option of retrofitting later.

It is conceivable to improve the heat transfer of the oil in the cylinder head, the use of ribbed bodies in the oil galleries, for example, by a rough surface design of the oil passages in the cylinder block 15 and head 12 - in particular by incorporation of a thread - whereby a reduction in the amount of oil flowing through is achieved.

In addition, additional active heat sources may be incorporated in the bypass line 23, e.g. electric heating elements or heating elements, preferably one or more PTC heating rods, EGR oil cooler (EGR cooler), full flow oil cooler or similar, to heat the oil in the oil channels in the warm-up phase.

Furthermore, it is additionally conceivable to direct the exhaust gas line 14 directly through or adjacent to the oil sump 1 or into the bypass line 23 via a second exhaust gas valve, at least in the warm-up phase, whereby an increase of the heat transfer is made possible by a multiple, and to an exhaust gas / oil heat exchanger 8 may be waived if necessary.

Furthermore, an engine control in the warm-up phase can initially regulate at least a small amount of the exhaust gas / oil heat exchanger 8 for heating the oil in the oil bypass line 23, and after some time shut off the oil flow through the bypass line 23 to coke in the exhaust gas - / oil heat exchanger 8 to avoid. Control variables for the control can be the higher the required oil pressure as a function of speed and load, and the desired oil temperature as a lower priority.

Furthermore, it is conceivable to exploit the height potential difference between cylinder head 12 and oil suction line 2 for improving the oil flow behavior in the bypass line 23, or to design this height potential constructively as large as possible.

In addition, the use of thermal insulation of the bypass line 23 and / or the EGR bypass (exhaust gas recirculation) upstream of the valve 17 by using a ceramic tube is advantageously conceivable to closed at another first exhaust gas recirculation valve 21, the temperature of the exhaust / oil heat exchanger 8 and the other first exhaust gas recirculation valve 21 to limit.

Preferably, an oil pan with line in front of the oil suction 2 in an oil pan, not shown, of the oil sump 1 are integrated to absorb the oil exiting from the bearings in the head and crankshaft while it is also warmed up, and feed directly to the oil pump 3, without the Heat oil sump 1. The oil bypass valve 17 may in this case also be integrated in the oil sump after merging the bypass line 23 and the line of oil sump, with a check valve must be present in the line of the oil sump, so that the oil does not flow from the bypass line 23 back into the oil sump can.

Advantageously, a combination of the oil pan with spray nozzles, which are arranged in the connecting rod for cooling the piston, may be provided in order to increase the volume flow of the oil flow, wherein the spray nozzles are not switched off in the cold start.

The exhaust gas flow for heating the oil in the bypass line 23 can basically be diverted as desired in the exhaust gas flow. Particularly advantageously, the exhaust gas before a turbocharger by means of a conventional EGR valve (exhaust gas recirculation valve) are diverted at a large distance from the turbocharger, the high mass flow of the exhaust gas can be achieved in a small size and independent of the EGR calibration. Thus, a warm-up of the oil can be achieved without affecting the combustion temperature and thus also the exhaust gas. As part of the use of exhaust gas recirculation, it may be advantageous if the EGR cooler assembly has a vertical gas guide at an angle up to 40 degrees to the vertical, so that condensation water can be discharged into an exhaust.

If the internal combustion engine 30 has no turbocharger or no exhaust gas recirculation, an additional flap in the main exhaust gas flow can generate a pressure difference, and thus conduct an increased volume flow through the exhaust gas / oil heat exchanger 8.

FIG. 6 shows a lubrication system with an exhaust / oil heat exchanger 8 which is arranged in the oil suction pipe 2 between the oil sump 1 and the oil pump 3, so that sets a negative pressure on the oil side in the exhaust / oil heat exchanger 8 compared to the environment and compared to the pressure in exhaust system. In the oil gallery 16 are sensors for oil pressure 32 and oil temperature 37. Between the catalyst 10 and exhaust / oil heat exchanger 8, a first exhaust bypass valve 41 is arranged, which closes the exhaust gas bypass 38 and the exhaust gas flow through the exhaust / oil heat exchanger 8 opens, as long as a limit oil temperature is fallen short of. The oil heats up faster and reduces fuel consumption, not only in the start-up phase but also when the engine is warm in city mode or at moderate speeds of up to 100 km / h. As soon as a limit oil temperature is exceeded, the first exhaust gas bypass valve 41 closes the exhaust gas flow through the exhaust gas / oil heat exchanger 8 and at the same time opens the exhaust gas bypass 38.

At the beginning of the Ölsaugrohres 2 is a suction hopper with screen 100 and the oil pump 3 delivers oil through an oil filter 101 in a lubrication system 16 via the Oil is supplied to a plurality of devices to be lubricated 31 such as bearings and other consumers.

Due to the negative pressure on the oil side of the exhaust / oil heat exchanger 8 is avoided in the event of leakage in the exhaust / oil heat exchanger 8, which no oil from the exhaust / oil heat exchanger 8 exit, and can drip onto the hot exhaust 14 or catalyst 10, where it could then ignite. The measured oil pressure 32 is compared to a limit pressure depending on the driving situation, which is predetermined for various states of the input speed, oil temperature 37, oil pump speed, vehicle accelerations, and lubricating oil levels in tables.

If a first limit pressure is exceeded, or if a limit difference between the predetermined pressure and the measured pressure is exceeded, a warning signal is output, when a second, lower limit pressure is exceeded, the drive speed is limited, and falls below a third, even lower limit pressure, the internal combustion engine off.

The invention is not limited to the illustrated lubrication systems. It is conceivable that the heat exchanger 26 is connected to the exhaust pipe 14 in order to effect a faster heating of the lubricating oil. The arrangement of the valves may vary, the valves may be arranged upstream and downstream of the various heat exchangers and vice versa. The invention may be used to lubricate engine parts, transmission parts or other moving components of a vehicle.

Claims (14)

1. Method for leakage detection of a lubrication system (16) to lubricate rotating or oscillating components of a combustion engine (30) or of a transmission, preferably an automatic transmission of a vehicle,
   characterized
   in that a leakage of the lubrication system (16) is detected by comparison of an oil pressure of the lubrication system (16) with a predefinable limit pressure taken from a table or from the engine characteristics for various values of speed, torque and oil temperature, and at least one of the further parameters of oil pump speed, valve setting of an oil pump volumetric flow control, vehicle acceleration, vehicle lateral acceleration and/or lubricating oil level, where if a first limit pressure is undershot a warning signal is given and/or if a second, lower limit pressure is undershot the speed of the combustion engine (30) is limited and/or if a third, even lower limit pressure is undershot the combustion engine (30) is switched off.
2. Method according to claim 1,
   characterized
   in that inside the lubrication system (16) an oil intake pipe (2) is arranged in an oil sump (1) and an oil bypass line (23) bypasses the oil return lines (19), where an oil bypass valve (17) is arranged in the oil bypass line (23) and the oil bypass line (23) and/or at least one of the oil return lines (19) is connected to the intake line of an oil pump (3) and to the pressure line of a lubrication system (16),
   where the bypass line (23)

   - in the case of a combustion engine (30) passes through at least one cylinder head (12) and/or at least one turbocharger (24), or;

   - in the case of a transmission through at least one exhaust/oil heat exchanger (8) of the combustion engine (30) and/or at least one electric heating element;

   where if a defined limit temperature is undershot and a defined minimum pressure of the lubricating oil in the pressure line of the lubrication system (16) is exceeded, the oil bypass valve (17) is at least partially opened such that at least a partial flow of the lubricating oil does not flow through the oil sump (1) in a warm-up phase of the lubrication system (16) until either the minimum pressure or the limit temperature are reached.
3. Method according to claim 2,
   characterized
   in that after completion of the warm-up phase and the limit temperature being exceeded the oil bypass valve (17) is closed and/or the delivery rate of the oil pump (3) is increased as soon as a specified speed at a given torque undershoots a speed limit value or a torque of the components to be lubricated at a given speed exceeds a specified torque limit value, in order to limit a fall of the oil pressure inside the oil line.
4. Method according to one of the preceding claims 1 to 3,
   characterized
   in that an exhaust/oil heat exchanger (8) is arranged in an oil intake pipe (2) between the oil pump (3) and the oil sump (1) such that a lower pressure develops on the oil side in the exhaust/oil heat exchanger (8) in comparison with the environment and in comparison with the pressure in the exhaust system.
5. Method according to claim 4,
   characterized
   in that the exhaust flowing through the exhaust/oil heat exchanger (8) flows upstream through an exhaust valve/exhaust gas recirculation valve (20, 21, 41), in that the exhaust valve/exhaust gas recirculation valve (20, 21, 41) is closed as soon as a specified limit temperature of the exhaust or of the lubricating oil is reached, and/or in that at least part of the exhaust is passed via a controllable second valve directly above or adjacent to the oil sump (1) into or through an oil pan or into the bypass line (23) in order to increase the heat transfer.
6. Method according to claim 4 or 5,
   characterized
   in that the exhaust flowing through the exhaust/oil heat exchanger (8) flows through an exhaust gas recirculation valve (21) and is connected downstream as an exhaust recirculation line (22) to the intake manifold (9) of a combustion engine (30), and in that the exhaust gas recirculation valve (21) is at least partially closed as soon as a specified limit temperature of the exhaust or a specified volumetric flow of the exhaust return line is reached.
7. Method according to one of claims 4 to 6,
   characterized
   in that exhaust of the combustion engine (30) flowing parallel to the exhaust/oil heat exchanger (8) flows through a third exhaust valve (13) and in that the third exhaust valve (13) is temporarily at least partially closed in order to increase the exhaust flow and hence also the heat transfer in the exhaust/oil heat exchanger (8).
8. Method according to one of the preceding claims 2 to 7,
   characterized
   in that downstream of the oil pump (3) an additional heat exchanger (26) and a first oil valve (29) are arranged for cooling, in that the first oil valve (29) is at least partially opened when a specified limit value for the lubricating oil temperature is exceeded or undershot or when a specified limit value for the coolant inlet temperature (27) or the coolant outlet temperature (28) is undershot, where a second oil valve (25) is arranged preferably in the lubricating oil line parallel to the heat exchanger (26) and first oil valve (29), and in that the second oil valve (25) is at least partially closed when a specified limit value for the lubricating oil temperature is exceeded or undershot.
9. Device for leakage detection and heating up of a lubrication system (16) of rotating or oscillating components for a combustion engine (30) or a transmission, preferably an automatic transmission, for implementation of a method according to one of claims 1 to 8,
   characterized
   in that an exhaust/oil heat exchanger (8) is arranged in an oil intake pipe (2) between the oil pump (3) and the oil sump (1), where a lower pressure can be set on the oil side in the exhaust/oil heat exchanger (8) in comparison with the environment and in comparison with the pressure in the exhaust system, such that in the event of a leakage an oil exit from the exhaust/oil heat exchanger (8) is ruled out.
10. Device according to claim 9,
    characterized
    in that a third exhaust valve (13) is arranged parallel to the exhaust/oil heat exchanger (8) in an exhaust bypass line (38) bypassing the exhaust/oil heat exchanger (8) in order to increase the exhaust flow and hence the heat transfer in the exhaust/oil heat exchanger (8) at least temporarily.
11. Device according to claim 9 or 10,
    characterized
    in that the exhaust/oil heat exchanger (8) comprises an air blower that pumps cooling air through the exhaust/oil heat exchanger (8) into the exhaust line, in particular when an exhaust bypass line (38) is opened.
12. Device according to one of claims 9 to 11,
    characterized
    in that a butterfly valve is provided as a third exhaust valve (13) for actuating the exhaust bypass line (38), said valve isolating the exhaust/oil heat exchanger (8) completely from the exhaust line in the heat exchanger bypass mode, and/or a fourth exhaust valve is arranged on the other side of the exhaust/oil heat exchanger (8), where said fourth exhaust valve preferably automatically opens to the environment as a pressure relief valve when the exhaust heat exchanger (8) is separated by the butterfly valve (39) from the exhaust line and the air blower is active, or the fourth exhaust valve is opened when the air blower is activated, thereby avoiding an increase in an exhaust counter-pressure.
13. Device according to one of claims 9 to 12,
    characterized
    in that the oil intake pipe (2) is connected to an oil bypass line (23) bypassing the oil return line (19), where an oil bypass valve (17) is arranged in the oil bypass line (23), and said oil bypass line (23) and/or at least one of the oil return lines (19) is connected to the intake line of an oil pump (3) and to the pressure line of a lubrication system (16), and the oil bypass line (23)

    - in the case of a combustion engine (30) passes through at least one cylinder head (12) and/or at least one turbocharger (24), or;

    - in the case of a transmission through at least one exhaust/oil heat exchanger (8) of the combustion engine (30) and/or at least one electric heating element;

    and in that at least a partial flow of the lubricating oil does not flow through the oil sump (1) in a warm-up phase of the lubrication system (16) until either a limit oil pressure or a limit oil temperature is reached.
14. Device according to claim 13,
    characterized
    in that furthermore the oil bypass line (23) and/or at least one of the oil return lines (19) is connected to the exhaust/oil heat exchanger (8) or to a further heat exchanger, and the exhaust/oil heat exchanger (8) is arranged downstream of the catalytic converter (10) in the exhaust system of a combustion engine (30) for heating the lubricating oil, and a first exhaust gas/exhaust gas recirculation valve (20, 41) is arranged upstream of the heat exchanger (8) and alters the throughflow depending on at least the oil temperature or exhaust temperature, where a further first exhaust gas recirculation valve (21) is arranged preferably downstream of the heat exchanger (8) and said further first exhaust gas recirculation valve (21) is connected downstream to the intake manifold (9) of a combustion engine.

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