Patent Application
20120260891
The present disclosure relates generally to a lubrication strategy for a high pressure fuel pump, and more particularly to a strategy for sharing lubricating oil between a flywheel housing and the high pressure fuel pump.
Common rail fuel systems typically include a fuel source and fuel delivery components for supplying fuel directly into cylinders of an internal combustion engine by way of a common rail. Fuel within the common rail may be pressurized to a relatively high pressure using one or more pumps, and may be delivered to fuel injectors through a plurality of individual fuel supply passages. For example, the fuel pumping arrangement may include a fuel transfer pump for drawing fuel from the fuel source and transferring it to a high pressure fuel pump. The high pressure fuel pump, which may increase the pressure of the fuel to a range of up to about 1,800 bar, supplies high pressure fuel to the common rail.
While the fuel transfer pump may be electrically operated or engine driven, the high pressure fuel pump is generally engine driven due to the high pressures that are required. Typically, the high pressure fuel pump is chain or belt driven by the crankshaft and positioned at the side of the engine. According to one example, U.S. Pat. No. 6,070,564 to Hiraoka et al. teaches an outboard motor having a crankshaft rotatable about a vertically disposed axis. Mounted above the flywheel and connected for rotation with the crankshaft is a first drive pulley which drives a toothed drive belt. The drive belt in turn drives another drive pulley that is connected to the input shaft of a drive transmission for the high pressure fuel pump. With the fuel pump positioned to the side of the engine, it may be difficult to access the pump and associated fuel lines for maintenance and repair.
The present disclosure is directed to one or more of the problems set forth above.
In one aspect, an internal combustion engine includes an engine block defining at least one row of cylinders extending from a first end toward a second end. A flywheel housing is attached to the first end of the engine block and includes a pump engagement face having a first pump lubrication supply port opening therethrough. A high pressure fuel pump includes a flywheel housing engagement face having a second pump lubrication supply port opening therethrough. The pump engagement face of the flywheel housing abuts the flywheel housing engagement face of the high pressure fuel pump such that the first pump lubrication supply port and the second pump lubrication supply port are in fluid communication.
In another aspect, a method of operating an internal combustion engine includes a step of circulating lubricating oil through an engine block. This step includes supplying the lubricating oil to a high pressure fuel pump along a pump lubrication pathway having an upstream segment defined, at least in part, by a flywheel housing, a first pump lubrication supply port and a second pump lubrication supply port. The method also includes a step of sealing against leakage between a pump engagement face of the flywheel housing and a flywheel housing engagement face of the high pressure fuel pump at the pump lubrication pathway using a sealing member.
In yet another aspect, a high pressure fuel pump for an internal combustion engine includes a fuel pump housing having a first end and a second end. A drive shaft is positioned within the fuel pump housing and extends from the first end to the second end. The high pressure fuel pump also includes a plurality of pistons configured to reciprocate within a fluid chamber upon rotation of the fuel pump drive shaft. A planar face defines at least a portion of the first end of the fuel pump housing and has a pump lubrication supply port and a pump lubrication drain port opening therethrough. The planar face also includes an annular groove positioned about the pump lubrication supply port.
Referring to the schematic of
The engine system 10 may also include a fuel system 26, for supplying fuel into each of the combustion chambers 18 during operation of the internal combustion engine 12. The fuel system 26, also referred to as a common rail fuel system, may include a fuel tank 28 configured to hold a supply of fuel, and a fuel pumping arrangement 30 configured to pressurize the fuel and direct the pressurized fuel to a plurality of fuel injectors 32 by way of a common rail 34. The fuel pumping arrangement 30 may include one or more pumping devices that function to increase the pressure of the fuel and direct one or more pressurized streams of fuel to the common rail 34 using fuel lines 36. For example, the fuel pumping arrangement 30 may include a fuel transfer pump 38, or low pressure fuel pump, that draws fuel from the fuel tank 28 and pumps pressurized fuel to a high pressure fuel pump 40. The high pressure fuel pump 40 increases the pressure of the fuel and pumps the high pressure fuel to the common rail 34. One or both of the fuel transfer pump 38 and the high pressure fuel pump 40 may be operably connected to the internal combustion engine 12 and driven by the crankshaft 22. For example, the high pressure fuel pump 40 may be connected to the crankshaft 22 through a gear train 42, a specific example of which will be discussed later in greater detail.
The fuel injectors 32 may be disposed within a portion of the cylinder block/head 14, as shown, and may be connected to the common rail 34 via a plurality of individual branch passages 44. Each fuel injector 32 may be operable to inject an amount of pressurized fuel into an associated combustion chamber 18 at predetermined timings, fuel pressures, and fuel flow rates. The timing of fuel injection into the combustion chambers 18 may be synchronized with the motion of the pistons 20. For example, fuel may be injected as piston 20 nears a top-dead-center position in a compression stroke to allow for compression-ignited combustion of the injected fuel. Alternatively, fuel may be injected as piston 20 begins the compression stroke heading towards a top-dead-center position for homogenous charge compression ignition operation. As shown, fuel injectors 32 may also be fluidly connected to fuel tank 28 via one or more drain lines 45.
A control system 46 may be associated with fuel system 26 and/or engine system 10 to monitor and control the operations of the fuel pumping arrangement 30, fuel injectors 32, and various other components of the fuel system 26. In particular, and according to the exemplary embodiment, the control system 46 may include an electronic controller 48 in communication with the high pressure fuel pump 40 and each of the fuel injectors 32 via communication lines 50. For example, the electronic controller 48 may be configured to control pressurization rates and injection, thus improving performance and control of the internal combustion engine 12. Although a particular embodiment is shown, it should be appreciated that the control system 46 may be configured to provide any desired level of control, and may include any number of components and/or devices, such as, for example, sensors, useful in providing the desired control.
Turning now to
A flywheel housing 68 is attached to the first end 64 of the engine block 14 using known attachment means and houses or supports, at least partially, a gear train 70, shown in
As shown, the high pressure fuel pump 40 is mounted to the flywheel housing 68 at a position over and above the engine block 14. In addition, the high pressure pump 40 is positioned over and above a V shaped area “A” defined by the first and second row of cylinders 60 and 62. As should be appreciated, the term “above,” as used herein, means that one component is positioned at a higher location relative to another component. Specifically, the high pressure fuel pump 40 is situated above or is elevated with respect to the engine block 14 and the V shaped area “A” defined by the cylinders 16 relative to a gravitational pull. In addition, the term “over,” as used herein, means that one component has a position vertically above, or on top of, another component. Specifically, the high pressure fuel pump 40 is situated over the engine block 14 and the V shaped area “A”, such that the high pressure fuel pump 40 is in vertical alignment with the engine block 14 and the V shaped area “A.”
As shown in
The second end 82 of the high pressure fuel pump 40 may be attached to the engine block 14 using a bracket 88, or other similar component. The bracket 88 may be attached to the high pressure fuel pump 40 using bolts 90 and to the engine block 14 using bolts 92. Although bolted attachments are shown, it should be appreciated that the components described herein may be attached using any known fastening means incorporating any known fastening devices. Further, “attached,” as used herein, is used generally to describe components that are affixed, joined, connected, or otherwise held in contact.
By attaching the high pressure fuel pump 40 to the engine block 14, oscillation of the high pressure fuel pump 40 due to operation of the internal combustion engine 12 may be reduced. As should be appreciated, if the internal combustion engine 12 causes the high pressure fuel pump 40 to vibrate at its resonance frequency, such oscillation may result in damage to one or more components of the internal combustion engine 40. The bracket 88, also referred to as a vibration transfer reduction member, may prevent the high pressure fuel pump 40 from being cantilevered from the flywheel housing 68 and may reduce stress and damage that may be caused by vibrations.
Turning now to
The engine system 10 also includes a lubrication system 120, a schematic of which is shown in
Turning now to
In an assembled state of the flywheel housing 68 and the high pressure fuel pump 40, the pump engagement face 140 of the flywheel housing 68 abuts the flywheel housing engagement face 144 of the high pressure fuel pump 40 such that the first pump lubrication supply port 142 and the second pump lubrication supply port 146 are in fluid communication. To supply lubricating oil to the high pressure fuel pump 40, lubricating oil may first be supplied to an interior 152 of the flywheel housing 68 from the second lubrication passage 132 (
The flywheel housing engagement face 144 of the high pressure fuel pump 40 also includes at least one pump lubrication drain port 156 opening therethrough. The pump lubrication pathway 134 further includes a downstream segment 158 defined, at least in part, by the pump lubrication drain port(s) 156 and the flywheel housing 68. Therefore, during operation of the internal combustion engine 12, lubricating oil is pumped along the upstream segment 154 of the pump lubrication pathway 134 and into the high pressure fuel pump 40, where moving components within the high pressure fuel pump 40 are lubricated in a known manner. The lubricating oil is then drained, along the downstream segment 158, from the high pressure fuel pump 40, through the interior 152 of the flywheel housing 68, and into the sump 125 using gravity.
The present disclosure may be applicable to internal combustion engines having common rail fuel systems. Further, the present disclosure may be particularly applicable to positioning of the high pressure fuel pump relative to the engine block and the flywheel housing. Yet further, the present disclosure may be applicable to a lubrication strategy for the high pressure fuel pump. Specifically, lubricating oil may be shared between the flywheel housing and the high pressure fuel pump, which is at least partially supported on the flywheel housing.
Referring generally to
The high pressure fuel pump 40 is mounted, or attached, to the flywheel housing 68 at a position over and above the engine block 14 and a V shaped area “A” defined by the first and second row of cylinders 60 and 62. According to the exemplary embodiment, the high pressure fuel pump 40 may have a first end 80 attached to the flywheel housing 68 and a second end 82 attached to the engine block 14 via a bracket 88. During operation of the internal combustion engine 12, the first end 80 of the high pressure fuel pump 40 is supported using the flywheel housing 68. Oscillation of the high pressure fuel pump 40 is reduced using the bracket 88, or other vibration transfer reduction member, positioned between the second end 82 of the high pressure fuel pump 40 and the engine block 14. Such positioning may provide improved accessibility to the high pressure fuel pump 40 and corresponding fuel lines.
Also during operation, lubricating oil is circulated through the engine block 14 per the lubrication system schematic of
Lubricating oil is drained from the high pressure fuel pump 40 through at least one pump lubrication drain port 156 opening through the flywheel housing engagement face 144. More specifically, the lubricating oil is drained from the pump lubrication drain port 156, through an interior 152 of the flywheel housing 68, and into a sump 125 using gravity.
It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.
