Method and system for lubricating an apparatus

Abstract

This application relates to methods and systems for lubricating devices. Methods and systems for a compressed natural gas fuel rail are provided. In one example, a system includes a device having a first volume for containing compressed natural gas and a second volume for containing a lubricant, the first volume and the second volume being disposed in a single housing and separated by a barrier. Lubricant flow from the second volume to the first volume can be regulated by regulating a pressure of the second volume such that a pressure differential between the second volume and the first volume is increased to increase lubricant flow or the pressure differential is decreased to decrease lubricant flow.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of German Patent Application No. 102018200410.2, filed on January 11, 2018. The entire contents of the above application are incorporated herein by reference in their entirety for all purposes. Technical Field

[0003] The present description generally relates to a lubrication arrangement for a fuel injection nozzle of an internal combustion engine. Background Art

[0004] Recently, natural gas has also been increasingly used as a fuel for motor vehicles with corresponding engines. Storage, transportation, and refueling can be carried out as compressed natural gas (CNG), which is highly compressed but still gaseous natural gas, or liquefied natural gas (LNG), which is natural gas liquefied by severe cooling and maintained in liquid form by storage in pressurized containers.

[0005] Compared to gasoline and diesel, natural gas has the advantage of being cleaner burning. In the case of CNG, this is because, on the one hand, CNG is already present in the combustion chamber in a homogeneous gaseous form rather than in atomized form like gasoline and diesel, and on the other hand, the molecular chain contains only about half as many carbon atoms as hydrogen atoms in gasoline and diesel, meaning that when burned with oxygen, it produces more water (H2O) and less carbon dioxide (CO2), as well as less soot.

[0006] At normal atmospheric pressure (e.g., 1 atmosphere and / or approximately 1 bar), natural gas has a very low energy density compared to diesel fuel, e.g., the volumetric calorific value of natural gas, 0.036 MJ / L, is lower than the volumetric calorific value of diesel, 34.7 MJ / L. Natural gas is compressed to approximately 200 bar in order to be able to carry a sufficient amount of energy with an acceptable volume in a motor vehicle.

[0007] The difference in the drive is that instead of a gasoline / air mixture, a natural gas / air mixture is compressed, ignited and burned in the cylinders.

[0008] Internal combustion engines running on CNG may include injection nozzles that differ from those found in gasoline and diesel engines. For continuous operation, minimal lubrication may be desirable, but CNG does not provide this, while gasoline and diesel can serve as additional lubricants. Consequently, CNG injection nozzles may require a secondary lubrication source, which is uncommon with gasoline and diesel engines. Leakage oil from the compressor at CNG filling stations to the inlet nozzles provides some lubrication. However, this is not reliable. Consequently, the lack of lubrication can lead to increased wear, limiting service life and operational reliability. Summary of the Invention

[0009] It is therefore an object of the present disclosure to indicate the manner in which the lubrication of injection nozzles of internal combustion engines, in particular those operating with CNG as fuel, can be improved.

[0010] The object of the invention is achieved by a device for metering lubricant for a fuel injection nozzle for injecting CNG into an internal combustion engine, wherein the injection rail has a first volume for holding the lubricant and a second volume for holding the CNG, wherein the first volume is separated from the second volume by a separator element, which is embodied so as to be permeable to the lubricant.

[0011] The inflow of lubricant can be influenced in a targeted manner by the separator element. During operation, a sufficient amount of lubricant can be supplied, as a result of which degradation due to lack of lubrication is reduced.

[0012] According to one embodiment, the separator element may include a sponge-like structure in at least some sections. For example, the separator element may be made of a foam material (e.g., plastic or metal). In this case, the separator element has an open-cell structure (e.g., unsealed cell walls) in the sections with the sponge-like structure. Thus, the separator element can receive fluids and allow them to pass through.

[0013] According to another embodiment, the separator element has a semi-permeable layer for the lubricant at least in certain sections. For example, the separator element can have sections that only allow molecules with less than a certain molar mass or colloids or particles less than a certain size to pass through, while relatively large molecules or colloids cannot pass through.

[0014] According to another embodiment, the separator element is a perforated plate at least in certain sections.The plate may be perforated by introducing and / or machining through holes during or after its manufacture.

[0015] According to another embodiment, lubricant can be fed into the second volume via an oil port. The oil port can be connected to a lubricant circuit of the internal combustion engine, which lubricates components of the internal combustion engine, such as pistons mounted in cylinders. For this purpose, the oil port can be connected to an oil gallery or the oil sump of the internal combustion engine. Furthermore, the oil port allows for convenient refilling when the lubricant supply is depleted.

[0016] According to another embodiment, the lubricant can be pressurized in the second volume via a pressure port. Thus, a feed pressure can be established, by which the lubricant can be fed to the fuel injection nozzle. This can occur without a pump.

[0017] According to another embodiment, the pressure port is connected to a gas line via a branch line, through which CNG can be fed into the first volume. Thus, the high gas pressure of the stored CNG is used to supply the feed pressure. A drive assembly for generating pressure can thus be omitted.

[0018] According to another embodiment, a gas pressure regulator is assigned to the branch line. This allows the gas pressure, and thus the feed pressure, to be regulated. This allows fluctuations in the pressure of the stored CNG to be balanced. If desired, the feed pressure can also be increased to increase the lubricant feed rate, if necessary.

[0019] In one example, the aforementioned issues can be addressed by a system comprising an apparatus including a first volume fluidly coupled to a lubricant port, and a second volume configured to deliver compressed natural gas directly to an injection rail, wherein the first volume and the second volume are separated by a separator element configured to allow lubricant to flow from the first volume to the second volume. In this manner, a fuel injector configured to inject a non-lubricating fuel can receive lubricant.

[0020] As an example, the amount of lubricant flowing from the first volume to the second volume can be regulated by adjusting the pressure of the first volume. The first volume pressure can be regulated by one or more of a pressure regulator and / or an oil pump. By doing so, the device can precisely flow the required amount of lubricant, ensuring adequate lubrication of the fuel injector while preventing over-lubrication, thereby conserving lubricant for other components.

[0021] It should be understood that the above summary is provided to introduce some concepts further described in the detailed description in a simplified form. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the appended claims. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of an engine included in a hybrid vehicle is shown.

[0023] Figure 2 A schematic diagram of an internal combustion engine with a device for metering lubricant according to a first embodiment is shown.

[0024] Figure 3 A schematic diagram of an internal combustion engine with a device for metering lubricant according to a second embodiment is shown.

[0025] Figure 4 A method for metering lubricant flow is shown.

[0026] Figure 5 An engine operating sequence is shown in which lubricant pressure adjustments are plotted in response to a desired lubrication quantity. DETAILED DESCRIPTION

[0027] The following description relates to systems and methods for an apparatus configured to provide lubricant and fuel to a plurality of fuel injectors configured to inject compressed natural gas (CNG). An example of a fuel injector is shown in FIG. Figure 1 Here, the injector is positioned to inject directly into the combustion chamber. Figure 2 and Figure 3 An alternative embodiment of a device is shown, the device comprising a first volume configured to receive lubricant and a second volume configured to receive CNG, wherein the first volume and the second volume are arranged in a common housing and separated from each other by a barrier. The barrier may be at least partially porous to allow the lubricant to pass through to the second volume. A method for regulating the amount of lubricant flowing from the first volume to the second volume is provided in Figure 4 The engine operation sequence showing the change in lubrication quantity based on the pressure difference between the first volume and the second volume is shown in FIG. Figure 5 Shown in.

[0028] Figures 1 to 3An example configuration with relative positioning of various components is shown. If shown as being in direct contact or directly coupled to each other, these elements may be referred to as being in direct contact or directly coupled, respectively, in at least one example. Similarly, in at least one example, elements shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. As an example, components placed in coplanar contact with each other may be referred to as being in coplanar contact. As another example, in at least one example, components that are separated from each other with only space between them and no other components may be referred to as such. As yet another example, elements that are shown above / below each other, on opposite sides of each other, or to the left / right of each other may be referred to as such relative to each other. In addition, as shown in the figure, in at least one example, the topmost element or the topmost point of an element may be referred to as the "top" of a component, and the bottommost element or the bottommost point of an element may be referred to as the "bottom" of a component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the drawing and used to describe the positioning of elements of the drawing relative to each other. Therefore, in one example, an element shown as being above other elements is vertically positioned above the other elements. As yet another example, the shapes of elements depicted in the accompanying drawings may be referred to as having those shapes (e.g., such as circular, straight, planar, curved, rounded, chamfered, angled, etc.). Additionally, in at least one example, elements shown as crossing each other may be referred to as crossing elements or crossing each other. Additionally, in one example, an element shown within another element or an element shown outside another element may be referred to as such. It should be understood that one or more components referred to as "substantially similar and / or identical" may differ from one another according to manufacturing tolerances (e.g., within a deviation of 1-5%).

[0029] Figure 1 An engine system 100 for a vehicle is depicted. The vehicle may be a road vehicle having drive wheels that contact a road surface. The engine system 100 includes an engine 10 that includes a plurality of cylinders. Figure 1 One such cylinder or combustion chamber is depicted in detail. The various components of engine 10 may be controlled by electronic engine controller 12 .

[0030] Engine 10 includes a cylinder block 14 and a cylinder head 16. Cylinder block 14 includes at least one cylinder bore, and cylinder head 16 includes an intake valve 152 and an exhaust valve 154. In other examples, where engine 10 is configured as a two-stroke engine, cylinder head 16 may include one or more intake and / or exhaust ports. Cylinder block 14 includes cylinder walls 32, with piston 36 positioned therein and connected to crankshaft 40. Thus, when coupled together, cylinder head 16 and cylinder block 14 may form one or more combustion chambers. Thus, the volume of combustion chamber 30 is adjusted based on the oscillation of piston 36. Combustion chamber 30 may also be referred to herein as cylinder 30. Combustion chamber 30 is shown communicating with intake manifold 144 and exhaust manifold 148 via respective intake valve 152 and exhaust valve 154. Each intake valve and exhaust valve may be operated by intake cam 51 and exhaust cam 53. Alternatively, one or more of the intake and exhaust valves may be operated by an electromechanically controlled valve coil and armature assembly. The position of intake cam 51 may be determined by intake cam sensor 55. The position of exhaust cam 53 may be determined by exhaust cam sensor 57. Thus, when valves 152 and 154 are closed, combustion chamber 30 and the cylinder bore may be fluidically sealed, preventing gas from entering or leaving combustion chamber 30.

[0031] Combustion chamber 30 may be formed by cylinder walls 32, piston 36, and cylinder head 16 of cylinder block 14. Cylinder block 14 may include cylinder walls 32, piston 36, crankshaft 40, and the like. Cylinder head 16 may include one or more fuel injectors (such as fuel injector 66), one or more intake valves 152, and one or more exhaust valves (such as exhaust valve 154). Cylinder head 16 may be coupled to cylinder block 14 via fasteners (such as bolts and / or screws). Specifically, when coupled, cylinder block 14 and cylinder head 16 may be in sealing contact with each other via a gasket, and thus, cylinder block 14 and cylinder head 16 may seal combustion chamber 30 such that gases may flow into combustion chamber 30 only through intake manifold 144 when intake valve 152 is open and / or flow out of combustion chamber 30 through exhaust manifold 148 when exhaust valve 154 is open. In some examples, each combustion chamber 30 may include only one intake valve and one exhaust valve. However, in other examples, engine 10 may include more than one intake valve and / or more than one exhaust valve in each combustion chamber 30 .

[0032] In some examples, each cylinder of engine 10 may include a spark plug 192 for initiating combustion. Under select operating modes, ignition system 190 can provide an ignition spark to cylinder 14 via spark plug 192 in response to spark advance signal SA from controller 12. However, in some embodiments, spark plug 192 may be omitted, for example, where engine 10 may initiate combustion by auto-ignition or by fuel injection, as is the case with some diesel engines.

[0033] Fuel injector 66 may be positioned to inject fuel directly into combustion chamber 30, a process known to those skilled in the art as direct injection. Fuel injector 66 delivers liquid fuel in proportion to the pulse width of signal FPW from controller 12. Fuel is delivered to fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. Driver 68 provides operating current to fuel injector 66 in response to controller 12. In some examples, engine 10 may be a compressed natural gas (CNG) engine, and the fuel tank may contain CNG stored at high pressure (e.g., 200 bar), which may be injected into combustion chamber 30 via injector 66. However, in other examples, engine 10 may be configured to operate with other non-lubricating fuels. In one example, engine 10 operates exclusively on CNG.

[0034] Intake manifold 144 is shown communicating with throttle 62, which adjusts a position of throttle plate 64 to control airflow to engine cylinders 30. This may include controlling the airflow of pressurized air from intake boost chamber 146. In some embodiments, throttle 62 may be omitted, and airflow to the engine may be controlled by a single air intake system throttle (AIS throttle) 82 coupled to intake passage 42 and located upstream of intake boost chamber 146. In another example, AIS throttle 82 may be omitted, and airflow to the engine may be controlled using throttle 62.

[0035] In some embodiments, engine 10 is configured to provide exhaust gas recirculation, or EGR. When included, EGR can be provided as high-pressure EGR and / or low-pressure EGR. In examples where engine 10 includes low-pressure EGR, low-pressure EGR can be provided to the engine intake system via EGR passage 135 and EGR valve 138 from a location in the exhaust system downstream of turbine 164, downstream of air intake system (AIS) throttle 82 and upstream of compressor 162. When there is a pressure differential to drive flow, EGR can be drawn from the exhaust system into the intake system. The pressure differential can be created by partially closing AIS throttle 82. Throttle plate 84 controls the pressure at the inlet of compressor 162. The AIS can be electrically controlled and its position can be adjusted based on an optional position sensor 88.

[0036] Ambient air is drawn into combustion chamber 30 via intake passage 42, which includes air filter 156. Thus, air first passes through air filter 156 and enters intake passage 42. Compressor 162 then draws air from intake passage 42 to pass through compressor outlet pipe ( Figure 1164 is a turbocharger (not shown) that supplies compressed air to boost chamber 146. In some examples, intake passage 42 may include an air box (not shown) with a filter. In one example, compressor 162 may be a turbocharger, in which the power to compressor 162 is drawn from the exhaust flow via turbine 164. Specifically, the exhaust gas may rotate turbine 164, which is coupled to compressor 162 via shaft 161. Wastegate 72 allows exhaust gas to bypass turbine 164, thereby allowing control of boost pressure under varying operating conditions. Wastegate 72 may be closed (or the opening of the wastegate may be reduced) in response to increased boost demand (e.g., during an operator's accelerator pedal press). By closing the wastegate, the exhaust pressure upstream of the turbine may be increased, thereby increasing turbine speed and peak power output. This allows for increased boost pressure. Additionally, when the compressor recirculation valve is partially open, the wastegate may be moved toward a closed position to maintain the desired boost pressure. In another example, wastegate 72 may be opened (or its opening may be increased) in response to a reduced boost demand (e.g., during an operator tip-out). By opening the wastegate, exhaust pressure may be reduced, thereby reducing turbine speed and turbine power. This allows for a reduction in boost pressure.

[0037] However, in alternative embodiments, compressor 162 may be a supercharger, in which power to compressor 162 is drawn from crankshaft 40. Thus, compressor 162 may be coupled to crankshaft 40 via a mechanical linkage, such as a belt. In this way, a portion of the rotational energy output of crankshaft 40 may be transferred to compressor 162 to power compressor 162.

[0038] A compressor recirculation valve (CRV) 158 may be provided in a compressor recirculation path 159 around compressor 162 to allow air to move from the compressor outlet to the compressor inlet in order to reduce the pressure that may be generated across compressor 162. A charge air cooler 157 may be located in plenum 146 downstream of compressor 162 for cooling the charge of pressurized air delivered to the engine intake. Figure 1 In other examples shown, charge air cooler 157 may be positioned downstream of electronic throttle 62 in intake manifold 144. In some examples, charge air cooler 157 may be an air-to-air charge air cooler. However, in other examples, charge air cooler 157 may be a liquid-to-air cooler.

[0039] In the depicted example, compressor recirculation path 159 is configured to recirculate cooled compressed air from upstream of charge air cooler 157 to the compressor inlet. In an alternative example, compressor recirculation path 159 may be configured to recirculate compressed air from downstream of the compressor and downstream of charge air cooler 157 to the compressor inlet. CRV 158 may be opened and closed by an electrical signal from controller 12. CRV 158 may be configured as a three-state valve having a default half-open position, from which CRV 158 may be moved to a fully open position or a fully closed position.

[0040] Universal Exhaust Gas Oxygen (UEGO) sensor 126 is shown connected to exhaust manifold 148 upstream of emission control device 70. Alternatively, a two-state exhaust gas oxygen sensor may replace UEGO sensor 126. In one example, emission control device 70 may include multiple catalyst bricks. In another example, multiple emission control devices may be used, each having multiple bricks. Although the depicted example shows UEGO sensor 126 upstream of turbine 164, it will be understood that in alternative embodiments, the UEGO sensor may be positioned in the exhaust manifold downstream of turbine 164 and upstream of emission control device 70. Additionally or alternatively, emission control device 70 may include a diesel oxidation catalyst (DOC) and / or a diesel cold start catalyst, a particulate filter, a three-way catalyst, a NOx trap, a selective catalytic reduction device, and combinations thereof. In some examples, the sensor may be arranged upstream or downstream of emission control device 70, where the sensor may be configured to diagnose the condition of emission control device 70.

[0041] The controller 12 Figure 11 is a microcomputer including a microprocessor unit (CPU) 102, input / output ports (I / O) 104, read-only memory (ROM) 106, random access memory (RAM) 108, keep-alive memory (KAM) 110, and a conventional data bus. Controller 12 is shown receiving various signals from sensors coupled to engine 10, including, in addition to those signals described above: engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling sleeve 114; position sensor 134 coupled to input device 130 for sensing input device pedal position (PP) adjusted by vehicle operator 132; a knock sensor (not shown) for determining ignition of exhaust gases; a measurement of engine manifold pressure (MAP) from pressure sensor 121 coupled to intake manifold 144; a measurement of boost pressure from a pressure sensor coupled to boost chamber 146; an engine position sensor from Hall effect sensor 118 sensing the position of crankshaft 40; a measurement of air mass entering the engine from sensor 120 (e.g., a hot wire air flow meter); and a measurement of throttle position from sensor 58. Barometric pressure may also be sensed (sensor not shown) for processing by controller 12. In a preferred aspect of the present disclosure, the Hall effect sensor 118 generates a predetermined number of equally spaced pulses per crankshaft revolution, thereby enabling determination of engine speed (RPM). The input device 130 may include an accelerator pedal and / or a brake pedal. Thus, the output from the position sensor 134 may be used to determine the position of the accelerator pedal and / or brake pedal of the input device 130, and thus determine the desired engine torque. Thus, the desired engine torque requested by the vehicle operator 132 may be estimated based on the pedal position of the input device 130.

[0042] In some examples, vehicle 5 may be a hybrid vehicle with multiple torque sources available to one or more wheels 59. In other examples, vehicle 5 is a conventional vehicle with only an engine, or an electric vehicle with only one or more electric motors. In the example shown, vehicle 5 includes engine 10 and electric motor 52. Electric motor 52 may be a motor or a motor / generator (M / G). When one or more clutches 56 are engaged, crankshaft 40 of engine 10 and electric motor 52 are connected to wheels 59 via transmission 54. In the depicted example, a first clutch 56 is positioned between crankshaft 40 and electric motor 52, and a second clutch 56 is positioned between electric motor 52 and transmission 54. Controller 12 may send signals to the actuators of each clutch 56 to engage or disengage the clutches, thereby connecting or disconnecting crankshaft 40 from electric motor 52 and components connected thereto, and / or connecting or disconnecting electric motor 52 from transmission 54 and components connected thereto. Transmission 54 may be a gearbox, a planetary gear system, or other type of transmission. The powertrain system may be configured in various ways, including parallel, series, or series-parallel hybrid vehicles.

[0043] The electric motor 52 receives power from the traction battery 61 to provide torque to the wheels 59. The electric motor 52 may also operate as a generator to provide power to charge the battery 61, such as during braking operations.

[0044] The controller 12 receives the Figure 1 The signals of various sensors are used Figure 1 Various actuators of the controller adjust engine operation based on received signals and instructions stored in the controller's memory. For example, adjustments to the electric machine 52 may occur based on feedback from the ECT sensor 112. As will be described in greater detail below, the engine 10 and the electric machine 52 may be adjusted so that their operation may be delayed based on one or more of powertrain temperature, which may be estimated based on feedback from the ECT sensor 112, and the distance between the intended destination and the electric-only operating range.

[0045] Now turn Figure 2 , which shows an internal combustion engine 202, which is implemented as a traction engine of a motor vehicle. In one example, the internal combustion engine 202 can be similar to Figure 1 The engine 10 is used.

[0046] The internal combustion engine 202 in the present exemplary embodiment is a reciprocating piston internal combustion engine that is implemented as a spark ignition engine. In contrast to the present exemplary embodiment, the internal combustion engine 202 may also be implemented as a diesel engine. In addition, the internal combustion engine 202 may be turbocharged and / or supercharged. In addition, in the present exemplary embodiment, the internal combustion engine 202 is configured for intake manifold injection (e.g., as a self-inducted engine). In contrast to the present exemplary embodiment, the internal combustion engine 202 may also be configured for direct injection (e.g., as a self-inducted engine) without departing from the scope of the present disclosure. Figure 1 shown).

[0047] Internal combustion engine 202 can be configured to operate using CNG (compressed natural gas) as an energy source and / or fuel. CNG is understood herein to be natural gas that has been compressed but remains in the gaseous phase. In one example, CNG is compressed to approximately 200 bar. Thus, in this exemplary embodiment of internal combustion engine 202, a gas mixture consisting of air and natural gas is fed, whereas in a spark-ignition engine operating on gasoline, an air / fuel aerosol is fed.

[0048] Furthermore, the internal combustion engine 202 in this exemplary embodiment is operated at a throttle valve (eg, Figure 1 Downstream of the throttle valve 68) there are multiple fuel injection nozzles 230a, 230b, 230c and 230d. In one example, one of the multiple fuel injection nozzles can be similar to Figure 1 Fuel injector 66 is used.

[0049] Fuel injection nozzles 230a, 230b, 230c, and 230d each terminate at a respective end of the intake manifold, upstream of a respective cylinder inlet valve of internal combustion engine 202. In other words, internal combustion engine 202 may be configured for multi-point injection (MPI), wherein CNG is injected in a dispersed manner at respective ends of the injection manifold, upstream of the cylinder inlet valves.

[0050] Alternatively, fuel injection nozzles 230a, 230b, 230c, and 230d may also be configured to inject CNG directly into corresponding cylinders of internal combustion engine 202. In addition, internal combustion engine 202 may also be configured for center point injection (CPI) into the intake manifold of internal combustion engine 202.

[0051] For the desired operation of fuel injection nozzles 230a, 230b, 230c, and 230d, it is desirable to provide a threshold amount of lubrication to mitigate degradation of the fuel injection nozzles. However, this threshold lubrication may not be provided solely by the CNG fuel. As mentioned above, this problem may not exist in conventional fuel engines using diesel or gasoline, as diesel and gasoline can also serve as lubricants. Therefore, CNG fuel injection nozzles may require a separate lubrication source external to the CNG pipeline.

[0052] In order to supply a threshold amount of lubrication and thus increase the service life and operational reliability of the internal combustion engine 202, a device 204 for metering lubricant to the fuel injection nozzles 230a, 230b, 230c and 230d is provided.

[0053] In the exemplary embodiment, the device for metering lubricant 204 may include an injection rail 208 that may be connected to fuel nozzles 230a, 230b, 230c, and 230d in both a CNG-guiding manner and a lubricant-guiding manner.

[0054] Additionally, the device for metering lubricant 204 may include an oil port 220 and a pressure port 222 .

[0055] In the present exemplary embodiment, oil port 220 can be connected to a lubricant circuit (not shown) of internal combustion engine 202, with which components of internal combustion engine 202, such as pistons mounted in cylinders, can be lubricated. For this purpose, oil port 220 can be connected to an oil gallery or an oil sump of internal combustion engine 202. Contrary to the present exemplary embodiment, the oil port can also be used for convenient refilling when the lubricant supply is depleted.

[0056] The pressure port 222 may be connected to a gas line 216 in a CNG-guided manner via a branch line 218, and CNG may be fed to the injection rail 208 through the gas line 216. In this case, a gas pressure regulator 206 for regulating the gas pressure of the CNG is arranged on the gas line 216. The gas pressure regulator 206 may be a PID controller.

[0057] Via the branch line 218 , a feed pressure can be built up, by means of which lubricant can be fed to the fuel injection nozzles 230 a , 230 b , 230 c and 230 d during operation, as will be explained later.

[0058] The injection rail 208 may include a first volume 210 for holding lubricant and a second volume 214 for holding CNG. In this case, the first volume 210 may be separated from the second volume 214 via a separator element 212.

[0059] Gas line 216 may terminate in first volume 210, while oil port 220 and pressure port 222 both terminate in second volume 214. That is, gas line 216 may be fluidly coupled to first volume 210, while oil port 220 and pressure port 222 are fluidly coupled to second volume 214.

[0060] Separator element 212 may include a plate-like body. Furthermore, separator element 212 is implemented to be permeable to lubricant, such that during operation, a threshold amount of lubricant can pass from second volume 214 into first volume 210, and the lubricant can then pass from the first volume to fuel injection nozzles 230a, 230b, 230c, and 230d.

[0061] For this purpose, the separator element 212 in this exemplary embodiment has a sponge-like structure at least in certain sections. The separator element 212 can be made of a foam material (e.g., plastic or metal). In this case, the separator element has an open-cell structure in the sections having the sponge-like structure, so that the cell walls are not closed, but extend from the upper side 226 of the separator 212 on the second volume 214 side as far as the lower side 228 of the separator element 212 on the first volume 210 side. As a result, the separator element 212 can receive fluids and allow them to pass through.

[0062] Furthermore, the separator element 212 may include a semi-permeable layer for lubricant at least in certain sections. For example, the separator element 212 may have sections that allow only molecules with a molar mass less than a certain value or colloids or particles less than a certain size to pass through, while preventing relatively large molecules or colloids from passing through. Thus, liquids can be filtered by size.

[0063] Additionally, the separator element 212 may be a perforated plate at least in certain sections. The plate may be perforated during or after its manufacture by introducing through holes extending from the upper side 226 of the separator element 212 to the lower side 228 of the separator element 212 .

[0064] In one example, to prevent CNG from flowing from the first volume 210 to the second volume 214, the pressure of the first volume 210 can be maintained equal to or less than the pressure of the second volume 214. Additionally or alternatively, the separator element 212 can be configured to become saturated with lubricant such that the lubricant and the surface of the separator element 212 can combine to prevent CNG from flowing from the first volume 210 to the second volume 214.

[0065] During operation, CNG is fed from the high-pressure tank through gas line 216 to gas pressure regulator 206, and its pressure is reduced by gas pressure regulator 206 before being fed to fuel injection nozzles 230a, 230b, 230c, and 230d of internal combustion engine 202 through first volume 210 of injection rail 208. In one example, the CNG from the high-pressure tank may comprise a pressure of approximately 200 bar, wherein gas pressure regulator 206 reduces the pressure of the CNG to 10 to 20 bar before feeding the CNG to fuel injection nozzles 230a, 230b, 230c, and 230d.

[0066] At the same time, a reduced pressure (e.g., 30 bar) is applied to the lubricant that has been introduced into the first volume 210 via the oil portion 220. In one example, the lubricant is oil. Thus, the lubricant in the second volume 214 is at a higher pressure than the CNG in the first volume 210. The pressure difference has the effect of causing the lubricant to flow through the separator element 212 and then also pass from the first volume 210 to the fuel injection nozzles 230a, 230b, 230c, and 230d of the internal combustion engine 202.

[0067] Now turn Figure 3 , which shows a second embodiment 300 of a device 204 for metering lubricant. The second embodiment may be intended to improve the lubricant supply to the fuel injection nozzles 230a, 230b, 230c, 230d of an internal combustion engine 202 operating with CNG as fuel.

[0068] The device 204 for metering a lubricant according to the second exemplary embodiment 300 differs from the device 204 for metering a lubricant according to the first exemplary embodiment 200 in that a feed pressure regulator 224 is arranged in the branch line 218 .

[0069] The feed pressure regulator 224 may be a PID controller that regulates the gas pressure and, therefore, the feed pressure indirectly. In one example, the feed pressure regulator 224 may be electronically coupled to the controller 12 such that the feed pressure regulator 224 may receive a signal from the controller to regulate the pressure of the lubricant in the branch line 218.

[0070] By means of this device 204 for metering lubricant, the lubricant supply to the fuel injection nozzles 230a, 230b, 230c, 230d of the internal combustion engine 202 operated with CNG as fuel can also be improved.

[0071] Additionally or alternatively, a pump 342 can be fluidly coupled to the second volume 214 via the oil port 220. The pump 342 can flow lubricant from a lubricant source 344 to the oil port 220. The lubricant source 344 can be one or more of a crankcase, an oil sump, a transmission, and another device that receives lubricant (e.g., oil). In some examples, the pump can be used to regulate the pressure of the second volume 214. For example, if the pump 342 is commanded to flow more lubricant to the second volume 214, the pressure of the second volume can increase.

[0072] As described below, the pressure differential between first volume 210 and second volume 214 can determine the amount of lubrication provided to the multiple injectors. For example, if the pressure differential increases, more lubricant can flow from the second volume to the first volume. Accordingly, if the pressure differential decreases, less lubricant can flow from the second volume to the first volume. In one example, if the pressure differential is zero or less, no oil can flow from the second volume to the first volume.

[0073] Now turn Figure 4 , which shows a method 400 for regulating lubricant flow to a plurality of fuel injection nozzles. Instructions for executing method 400 and the remaining methods included herein may be provided by a controller based on instructions stored on a memory of the controller and in conjunction with information from sensors of the engine system (such as those described above with respect to Figure 1 According to the method described below, the controller can use the engine actuators of the engine system to adjust the engine operation.

[0074] Method 400 begins at 402 and includes determining current engine operating parameters. The current engine operating parameters may include, but are not limited to, one or more of throttle position, manifold vacuum, engine temperature, engine speed, EGR flow rate, and air / fuel ratio.

[0075] Method 400 proceeds to 404, which may include determining whether lubrication is desired, which may be determined based on one or more of the coefficient of friction, combustion temperature, and injection pressure. In some examples, the amount of lubrication may be tracked over time, where it may be desirable to maintain the amount of lubrication above a threshold amount. The threshold amount may be a non-zero number based on an amount of lubrication sufficient to mitigate degradation of the fuel injectors. If lubrication is not desired, method 400 may proceed to 406, which may include maintaining current engine operating parameters. Lubrication may not be desired when the fuel injectors are sufficiently lubricated (e.g., the amount of lubrication is greater than a threshold amount), if the fuel injectors are deactivated, and / or if the oil temperature is below a threshold temperature (e.g., a cold start). Additionally or alternatively, lubrication may not be desired based on the lubrication requirements of other lubricated components. For example, if the transmission lubrication requirement is relatively high (e.g., the required amount of lubrication is high), then lubrication of the transmission may take precedence over lubrication of the fuel injectors. As described below, in some examples, the amount of lubrication required by the fuel injectors may be reduced in response to other components requiring a relatively high amount of lubrication.

[0076] If lubrication is desired, method 400 may proceed to 408 to increase the oil pressure to a pressure greater than the CNG pressure. The CNG pressure may be substantially equal to the pressure provided by the first volume of the device (e.g., Figure 2 and Figure 3 Additionally or alternatively, the CNG pressure may be substantially equal to the pressure sensed by the pressure sensor in the first volume 210 of the device 204. Figure 2 and Figure 3 The oil pressure can be set by a variable oil pump (e.g., Figure 3 The oil pump 342 can be activated to increase the pressure of the second volume. The oil pump can cause a greater amount of oil to flow to the second volume of the device, causing the pressure of the second volume to increase. This can increase the pressure difference between the second volume containing lubricant (e.g., oil) and the first volume. In some examples, additionally or alternatively, pressure regulator 206 can be configured to increase the pressure of the lubricant in the second volume, as described above. In this way, each of the pump and pressure regulator can be utilized to increase the pressure of the second volume to regulate the flow of oil to the first volume, thereby regulating the flow of oil to the injector.

[0077] Method 400 may proceed to 410, which may include determining whether more lubrication is desired. If the engine load increases and / or if the engine temperature rises, more lubrication may be desired. If more lubrication is desired, method 400 may proceed to 412 to increase the oil pressure. Similar to 408, the oil pressure may be increased by increasing the amount of oil flowing from the oil pump to the second volume. In this way, the pressure difference between the second volume and the first volume may be increased, thereby allowing more oil to pass through the divider and enter the first volume, where the oil can mix with the CNG and flow to the fuel injector. It should be understood that the injector may include a device that allows the injector to inject CNG without injecting oil into the combustion chamber.

[0078] If more lubrication is not desired, method 400 may proceed to 414, which may include determining whether less lubrication is desired. If the engine load is decreasing and / or if the engine temperature is decreasing, less lubrication may be desired. Additionally or alternatively, less lubrication may be desired if another vehicle component requires a relatively large amount of lubrication, which component may take precedence over the fuel injectors. For example, if the transmission requires a large amount of lubrication, the lubrication requirements of the fuel injectors may be reduced so that the transmission lubrication requirements can be met. If less lubrication is desired, method 400 may proceed to 416, which may include reducing the oil pressure. This may include causing less oil to flow to the second volume, causing the pressure of the second volume to decrease, thereby reducing the pressure difference between the second volume (e.g., oil) and the first volume (e.g., a mixture of CNG and oil). By reducing the pressure difference, less oil can flow through the divider and into the first volume.

[0079] If less lubrication is not desired, method 400 may maintain current operating parameters (similar to 406 described above), which may include maintaining the flow rate of oil to the second volume so that the current amount of lubrication remains unchanged.

[0080] Now turn Figure 5 , which shows a graph 500 illustrating an engine operating sequence. Curve 510 shows the lubricant pressure in the second volume of the device. Curve 512, shown as a dashed line, shows the pressure of the first volume, which may include a mixture of lubricant and CNG. Curve 520 shows the amount of lubrication. Curve 522 (shown as a dashed line) shows the required amount of lubrication. During some conditions, curve 520 may track curve 522 so that the amount of lubrication provided is equal to the desired amount of lubrication. In such cases, curve 522 may be obscured by curve 520. Time increases from the left side of the graph to the right side of the graph.

[0081] Before t1, the pressure of the lubricant in the second volume (curve 510) is substantially equal to the pressure of the first volume (curve 512). As described above, the first volume may include a mixture of CNG and lubricant (e.g., oil). However, in the current case where the pressure of the second volume is substantially equal to the pressure of the first volume, the lubricant may not be able to reach the first volume from the second volume through the separator. In addition, the separator is shaped so that CNG cannot flow from the first volume through the separator to the second volume. This may be because the separator is saturated with lubricant, causing the holes in the separator to be filled with lubricant, thereby preventing CNG from flowing through. In addition, the amount of lubrication provided is relatively low (e.g., zero). However, if the required amount of lubrication is between a large amount and a small amount. Therefore, the fuel injector requires a certain amount of lubrication.

[0082] At t1, the second volume pressure begins to increase to a pressure greater than the second volume pressure. Figure 3 The oil pump 342 (using the oil pump 342) causes more lubricant to flow to the second volume, which can increase the pressure in the second volume. By doing so, the pressure in the second volume can increase. Between t1 and t2, the second volume increases to a pressure greater than the pressure in the first volume. This allows lubricant from the second volume to pass through the divider and into the first volume, where it can flow to the fuel injectors and provide a certain amount of lubrication. As shown in the figure, the pressure difference between the second volume and the first volume provides a lubricant amount (curve 520) that matches the required lubrication amount (curve 522).

[0083] At t2, the required amount of lubrication begins to increase. Between t2 and t3, the required amount of lubrication continues to increase above the amount of lubrication provided. This can occur in response to rising temperatures, where the lubricant density can decrease and the lubrication it provides is less effective.

[0084] At t3, as more lubricant flows to the second volume via the pump, the second volume pressure begins to increase. Consequently, the amount of lubricant provided also increases. Between t3 and t4, the second volume pressure rises to a pressure greater than the first volume pressure. In one example, the second volume pressure between t3 and t4 is greater than the second volume pressure between t1 and t2. Therefore, the pressure difference between the second volume and the first volume between t3 and t4 is greater than the pressure difference between t1 and t2. As a result, the amount of lubricant flowing to the fuel injector increases to match the increased lubrication required.

[0085] At t4, the required lubrication quantity begins to decrease. Between t4 and t5, the required lubrication quantity continues to decrease.

[0086] At t5, the pressure in the second volume begins to decrease in response to the decrease in the required lubrication quantity. Thus, as the pressure differential between the second volume and the first volume decreases, the amount of lubrication provided can also decrease. After t5, when the pressure in the second volume decreases to a pressure close to that of the first volume, the amount of lubrication provided becomes equal to the required amount of lubrication. This decrease in the pressure differential between the first and second volumes reduces the flow of lubricant from the second volume to the first volume. As a result, the amount of lubrication provided decreases to the required amount of lubrication.

[0087] In this manner, a device can include two volumes partially separated by a porous element, thereby selectively allowing material to transfer from the second volume to the first volume. The device can be configured to receive CNG in the first volume and lubricant in the second volume, wherein the amount of lubricant flowing from the second volume to the first volume can be metered. The technical effect of metering the lubricant flow to the first volume can provide a desired lubrication amount for the fuel injectors while retaining a sufficient amount of lubricant for other vehicle components.

[0088] In another representation, a system includes an apparatus comprising a first volume configured to deliver compressed natural gas directly to an injection rail, a second volume fluidly coupled to a lubricant port, wherein the first volume and the second volume are separated by a separator element shaped to allow lubricant to flow from the second volume to the first volume. The first example of the system also includes wherein the separator element is also shaped to prevent compressed natural gas from flowing from the first volume to the second volume. The second example of the system optionally includes the first example, further including wherein at least a portion of the separator element comprises a sponge structure. The third example of the system optionally includes the first example and / or the second example, further including wherein at least a portion of the separator element comprises a semi-permeable layer. The fourth example of the system optionally includes one or more of the first to third examples, further including wherein at least a portion of the separator element comprises a perforated plate. A fifth example of the system optionally includes one or more of the first to fourth examples, further comprising wherein the compressed natural gas is delivered to the first volume via a gas line, the gas line is coupled to a branch line including a pressure regulator for reducing the pressure of the compressed natural gas as it flows to the first volume, and wherein the branch line is coupled to a pressure port of the second volume.

[0089] In another further representation of the system, the system includes a housing including a first volume configured to receive fuel and a second volume configured to receive lubricant, wherein the first volume is directly coupled to a plurality of fuel injectors, wherein the second volume is separated from the first volume by a porous barrier configured to allow fluid to flow only from the second volume to the first volume; and a controller having computer-readable instructions stored on its non-transitory memory that, when executed, enable the controller to: regulate the flow of lubricant from the second volume to the first volume by regulating the pressure of the second volume. The first example of the system also includes a pressure regulator disposed in the gas line for depressurizing the fuel flowing to the first volume and increasing the pressure of the second volume. The second example of the system optionally includes the first example and further includes a lubricant pump configured to flow lubricant to the second volume, wherein the instructions further enable the controller to increase the flow of lubricant from the lubricant pump to the second volume to increase the flow of lubricant from the second volume to the first volume. A third example of a system optionally includes the first example and / or the second example, further comprising wherein the instructions further enable the controller to reduce the flow of lubricant from the lubricant pump to the second volume to reduce the flow of lubricant from the second volume to the first volume. A fourth example of a system optionally includes one or more of the first to third examples, further comprising wherein at least a portion of the porous barrier is one or more of a sponge, a semi-permeable membrane, and a perforated plate. A fifth example of a system optionally includes one or more of the first to fourth examples, further comprising wherein the fuel is compressed natural gas. A sixth example of a system optionally includes one or more of the first to fifth examples, further comprising wherein the second volume is free of fuel.

[0090] In another representation, a method includes increasing the pressure of a second volume of a housing, the second volume containing lubricant; and causing the lubricant to flow from the second volume to a first volume of the housing, the second volume being fluidly coupled to a gas line and a plurality of fuel injectors. The first example of the method further includes wherein the increasing is in response to an increase in lubricant demand, wherein the lubrication demand increases in response to an increase in lubricant temperature. The second example of the method optionally includes the first example and further includes decreasing the pressure of the second volume in response to a decrease in lubricant temperature. The third example of the method optionally includes the first example and / or the second example, further includes wherein causing the lubricant to flow from the second volume to the first volume further includes causing the lubricant to flow through a barrier separating the first volume from the second volume within the housing. The fourth example of the method optionally includes one or more of the first to third examples, further includes wherein the gas line is configured to flow compressed natural gas and the plurality of fuel injectors are configured to inject the compressed natural gas. The fifth example of the method optionally includes one or more of the first to fourth examples, further includes decreasing the pressure of the compressed natural gas in the gas line via a pressure regulator as the compressed natural gas flows to the first volume. A sixth example of a method optionally includes one or more of the first to fifth examples, further comprising equalizing pressure between the first volume and the second volume in response to an absence of a lubrication demand.

[0091] Note that the example control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and can be executed by a control system including a controller in combination with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Thus, the various actions, operations, and / or functions shown can be performed in the order shown, in parallel, or in certain cases omitted. Similarly, the order of processing is not required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations, and / or functions shown can be repeatedly performed depending on the specific strategy used. In addition, the described actions, operations, and / or functions can graphically represent code to be programmed into the non-transitory memory of a computer-readable storage medium in an engine control system, where the described actions are performed by executing instructions in a system including various engine hardware components in combination with an electronic controller.

[0092] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and these specific embodiments should not be construed as limiting, as many variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0093] As used herein, unless otherwise indicated, the term "about" is to be interpreted as meaning ±5% of the range.

[0094] The following claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. These claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are also regarded as included within the subject matter of the present disclosure.

Claims

1. A system for lubrication, comprising: An apparatus comprising a first volume configured to receive compressed natural gas via a gas line terminating in the first volume and deliver the compressed natural gas directly to an injection rail, and a second volume fluidly coupled to a lubricant port, wherein the lubricant port is an oil port terminating in the second volume, wherein the first and second volumes are separated by a separator element shaped to allow lubricant to flow from the second volume to the first volume. 2 . The system of claim 1 , wherein the separator element is further shaped to inhibit compressed natural gas from flowing from the first volume to the second volume.

3. The system of claim 1, wherein at least a portion of the separator element comprises a sponge structure.

4. The system of claim 1, wherein at least a portion of the separator element comprises a semi-permeable layer.

5. The system of claim 1, wherein at least a portion of the separator element comprises a perforated plate.

6. The system of claim 1 , wherein the gas line is coupled to a branch line including a pressure regulator for reducing the pressure of the compressed natural gas as it flows to the first volume, and wherein the branch line is coupled to a pressure port of the second volume.

7. A system for lubrication, comprising: a housing comprising a first volume shaped to receive fuel and a second volume shaped to receive lubricant, wherein the first volume is directly coupled to a plurality of fuel injectors, the first volume being configured to receive compressed natural gas via a gas line terminating in the first volume, wherein a lubricant port is an oil port terminating in the second volume, wherein the second volume is separated from the first volume by a porous barrier shaped to allow fluid to flow only from the second volume to the first volume; and A controller having computer-readable instructions stored on a non-transitory memory thereof that, when executed, enable the controller to: Lubricant flow from the second volume to the first volume is regulated by regulating the second volume pressure.

8. The system of claim 7, further comprising a pressure regulator disposed in the gas line for reducing the pressure of fuel flowing to the first volume and increasing the pressure of the second volume.

9. The system of claim 7, further comprising a lubricant pump configured to flow lubricant to the second volume, wherein the instructions further enable the controller to increase lubricant flow from the lubricant pump to the second volume to increase lubricant flow from the second volume to the first volume.

10. The system of claim 9, wherein the instructions further enable the controller to reduce the lubricant flow from the lubricant pump to the second volume to reduce the lubricant flow from the second volume to the first volume.

11. The system of claim 7, wherein at least a portion of the porous barrier is one or more of a sponge, a semi-permeable membrane, and a perforated plate.

12. The system of claim 7, wherein the fuel is compressed natural gas.

13. The system of claim 7, wherein the second volume is free of fuel.

14. A method for lubrication, comprising: increasing the pressure of a second volume of the housing, the second volume containing the lubricant; and Lubricant is caused to flow from the second volume to a first volume of the housing containing compressed natural gas, the first volume being fluidly coupled to a gas line and a plurality of fuel injectors terminating in the first volume, wherein the lubricant is received via a lubricant port, which is an oil port terminating in the second volume.

15. The method of claim 14, wherein the increasing is in response to an increased lubrication demand, wherein the lubrication demand increases in response to an increase in lubricant temperature.

16. The method of claim 14 further comprising decreasing the pressure of the second volume in response to a decrease in lubricant temperature.

17. The method of claim 14, wherein flowing lubricant from the second volume to the first volume further comprises flowing lubricant through a barrier separating the first volume from the second volume within the housing.

18. The method of claim 14, wherein the gas conduit is shaped to flow compressed natural gas and the plurality of fuel injectors are shaped to inject compressed natural gas.

19. The method of claim 18, further comprising reducing the pressure of the compressed natural gas in the gas line via a pressure regulator as the compressed natural gas flows to the first volume.

20. The method of claim 18, further comprising equalizing pressure between the first volume and the second volume in response to an absence of a lubrication demand.

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