Patent Application
20120240892
The present disclosure relates to an improved radial power generation fluid dynamic lubrication system. Specifically, a lubricant system for improved cooling and flow of the lubricant within a radial engine is disclosed.
Radial engines have been commonly used in a variety of applications involving transportation. Radial engines are generally externally air-cooled with a remote, external lubricant reservoir tank and cooler. The lubricant generally flows in a continuous closed loop through the cooler, tank and directly back to the internal components of the engine. A radial engine generally has a centrally located crankshaft and a master-and-articulating rod assembly. The rod assembly includes a master rod that is attached directly to the crankshaft, and a plurality of rods attached to the master rod and disposed in a radial relationship about the crankshaft. The rods are disposed to engage the crankshaft such that there is correspondence between the rotation of the crankshaft and the reciprocating motion of a plurality of pistons pinned to the rods and positioned within a plurality of corresponding cylinders. Generally, lubricant flows into the engine through the crankshaft and non-integral lifter galley and drains out through the crankcase to the cooler and tank.
The master-and-articulating rod assembly generally includes a master/main bearing that is positioned between the crankshaft and the master rod connection. The master bearing supports the master-and-articulating rod assembly on the crankshaft. Previous radial engines have been plagued with fatigue and wear issues. Overheating of the lubricant is also problematic and can ultimately result in premature failure of the bearing and rotating assembly.
Therefore, a need exists for an improved lubrication system to prevent premature failure of the rotating assembly, as well as to minimize maintenance costs by increasing the Time Between Overhauls (TBO).
An engine lubrication device is disclosed. The device may include at least one lubricant supply pump, a crankcase having a first cavity and a second cavity, a first flow path extending through at least one master rod of a rotating assembly, a second flow path extending internally through at least one wall of the crankcase, and at least one scupper extending into the first cavity and fluidly connecting the first cavity with the second cavity. The lubricant may be supplied from the at least one lubricant supply pump, and through the first flow path exiting into the first cavity.
While the claims are not limited to the illustrated examples, an appreciation of various aspects is best gained through a discussion of various examples thereof. Referring now to the drawings, illustrative examples are shown in detail. Although the drawings represent the various examples, the drawings are not necessarily to scale and certain features may be exaggerated to better illustrate and explain an innovative aspect of an example. Further, the examples described herein are not intended to be exhaustive or otherwise limiting or restricting to the precise form and configuration shown in the drawings and disclosed in the following detailed description. Exemplary illustrations of the present invention are described in detail by referring to the drawings as follows.
Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed apparatuses and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the disclosed device. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.
A lubrication system for a radial engine is disclosed. For purposes of clarity, a radial engine, configured as a power generation unit with an associated electrical generator, will be described. However, it should be known that the disclosed improved lubrication system may be utilized in various radial engine applications, such as, but not limited to, fixed wing aircraft, rotary aircraft, automobiles, motorcycles, boats and other applicable uses of a radial engine. Additionally, the disclosed lubricant system may be utilized in various orientations and configurations, such as, but not limited to, vertical, horizontal and other various angled positions as would be suitable for a radial engine.
The improved lubricant system may include an improved external supply and scavenge/recirculation system, including an electronic lubricant pump with a plurality of valves and lubricant feed lines entering the radial engine to ensure generally instantaneous lubricant pressure. The lubricant pump may be used to prime and pressurize the system to provide lubricant to the rotating assembly prior to and during start-up. A temperature controlled lubricant cooler bypass valve may be used to improve efficiency and power generation at start-up. The external recirculation portion may include at least one scavenge pump for the removal of the lubricant from the internal areas of the radial engine after shutdown to avoid flooding the cylinders.
As is discussed in detail below, the lubricant pump directly connects the external supply system with the internal flow paths within a rotating assembly. Specifically, a flow path extends from the pump through the crankshaft. The crankshaft may be fluidly connected to the master connecting rod, which may be fluidly connected via an internal flow path to the link rods at a first end. Both the master connecting rod and the link rods include longitudinally extending internal flow paths that extend from the first end to a second end. The second ends are rotatively connected to an underside of a piston through a wrist pin. The second ends further include piston sprayer nozzles that provide increased and directed flow to the underside of the pistons.
An additional flow path may be created through the lubricant pump that may be fluidly connected to the lubricant galley lines. The lubricant galley lines are internal to the crankcase and provide a lower pressure lubricant supply to a hydraulic lifter. The hydraulic lifter may be fluidly connected to a rocker arm through a hollow push rod. The hollow push rod transfers both linear motion and lubricant to the rocker arm from the hydraulic lifter. The rocker arm diverts the lubricant to the moving parts within the rocker box attached to the head which houses the intake and exhaust systems, as well as a spark plug and may be attached to a cylinder sleeve to create a combustion chamber. The intake and exhaust system within the head includes an intake valve and an exhaust valve that may be isolated from the lubricant through a valve shaft seal. The head also includes a plurality of lubricant drain back apertures to direct the used lubricant either to an adjacent cylinder assembly, to a sump or to the cam and lifter side of the crankcase and gearbox. The crankcase may be fluidly sealed during operation and transfers lubricant through lubricant lines and lubricant passageways that may be fluidly connected to at least one pump.
During operation of the radial engine, the rotating assembly includes a crankshaft, master connecting rod, link connecting rods and pistons. As discussed above, the lubricant flows through these components and may be released or drains into the crankcase. As the rotating assembly rotates, the lubricant may be forced radially outward through centrifugal forces, which result in the lubricant being churned and aerated to a point where the lubricant may be broken down or sheared, resulting in overheating. One element used to reduce churning and aeration may be a small louver, or scupper, that projects inwardly towards the rotating assembly and away from the wall separating the crankcase internal area from the cam and lifter side of the crankcase.
As is further discussed below, the scuppers work to deflect the lubricant, that may be flowing about the crankcase, and pull it into the lifter area. This action may reduce windage and aeration of the lubricant, which may lead to better operating quality and conditions, as well as, reduced heat generation. The deflection and removal may allow the lubricant to be scavenged via a scavenging pump that pulls the lubricant out of the crankcase and into the external scavenging system for cooling, storage or reintroduction into the flow path of the radial engine. The removal of the lubricant may help to reduce the volume of lubricant required in the crankcase as well as reducing the potential of flooding in the lower cylinders. By creating a flow path from the crankcase to the bell housing or lifter side of the case, the scuppers create an additional path for venting. Additionally, by continually injecting cool treated lubricant back into the process, the lubricant may help to prevent premature failure and extend the life of the rotating assembly.
Additionally, upon shutdown of the radial engine, the scavenging portion of the external lubricant treatment system begins to draw the remaining lubricant out of both sides of the crankcase. This may be done to eliminate any leftover lubricant to ensure the sump is dry after shutdown, minimizing or eliminating any lubricant migration into the combustion chamber of the lowest cylinders.
Turning to the illustrative embodiments,
As illustrated, the cylinder heads 151 may include intake ports 264 and exhaust ports 270. The intake ports 264 may be fluidly connected to a gas air mixer 256 through at least one intake tube 274. The exhaust ports 270 may be fluidly connected to a muffler or exhaust silencer 214 (see
Turning to
The integrated galley line 168 may provide lubrication and hydraulic pressure from at least one pump 172 to the hydraulic lifters 164. The lubricant 120 supplied to the lubricant galley line 168 may be maintained at approximately 30-80 PSI and have a flow rate of approximately 6-11 GPM while the lubricant 120 that may be supplied through the at least one pump 172 that may be fluidly connected to a crankshaft 210 (see
As illustrated, the crankcase 186 includes the hydraulic lifter 164 positioned in the boss 180 on the lifter/cam side of the crankcase 186. The lifter 164 may be activated by an internally rotating cam (not shown) rotatively connected to the crankshaft 210. The cam may travel along an outer circumference of the internal cavity 190 to engage the lifter 164, resulting in activation of a pushrod 222 (see
Returning to
Turning to
As specifically illustrated in
Once the master rod 158 may be positioned on the crank pin 236, the crankshaft face 237 and associated bull nose counter weight boats 250 are affixed to the crank pin 236. Specifically, the crankshaft face 237 may be clamped down by threadingly engaging the bolt to engage the faces 237 around the crank pin 236. The counter weight boats 250 may be loosely attached to the crankshaft faces 237 using a pin and bolt system. This loose fit allows the counter weight boats 250 to move and remain balanced during pendulum harmonic dampener rotation of the radial engine 100 components. The counter weight boats 250 may be made of cast iron or other known material for constructing counter weights. The boats 250 have been machined to a bull nose configuration, which includes fillets and rounds, providing a smooth outer surface thereby removing any sharp or blunt edges from the counter weight boats 250. The smooth and rounded edges help to minimize any aeration or shearing of the lubricant 120 during normal operation of the radial engine 100. The bull nose configuration allows the counter weight boat 250 to essentially float through the liquid as the rotating assembly 153 moves radially through the engine cycle.
In order to provide lubricant 120 to the rotating assembly 153, and the other moving parts within the radial engine 100, the crankshaft 210 may be configured with an internal lubricant passageway 243. Additionally, the master rod 158 and link rod 170 may also be configured with corresponding lubricant passageways 253, 255 to mate with the crankshaft's 210 lubricant passageways 243. As specifically illustrated in
As illustrated in
During operation of the radial engine 100, rotating assembly 153 may be pressurized with lubricant 120 to prolong the life of the radial engine 100. As discussed above, the lubricant 120 flows through rotating assemblies' 153 components to ultimately eject out of the underside of each piston 156. Once the lubricant 120 is released it becomes a free flowing mass that may be forced radially outward or flung throughout the crankcase internal cavity 190. The rotational forces present within the cavity 190 may prevent the lubricant 120 from naturally flowing downward to at least one drain aperture (not shown) in the base of the crankcase 186. Thus, as the rotating assembly rotates the lubricant 120 may be churned and aerated to a point where the lubricant 120 may be broken down or sheared resulting in overheating. One element used to combat such an outcome is a small louver or scupper 194.
Specifically turning to
Turning to
The external lubricant filtration system 318 may be configured with a lubricant pump pressure section 320 and a lubricant pump scavenger section 322. The external lubricant filtration system 318 may include a prime pump 324, at least one of a remotely-mounted full-flow lubrication filter 378, lubricant cooler 280, and lubricant reservoir 276, as shown. A crankshaft lubricant feed check valve 326, a lifter valley check valve 328, sump tank 330, electric scavenge pump 332 and bypass valve 334 are included. The bypass valve 334 may be temperature controlled valve to improve system efficiency and when not in use, allows the lubricant 120 to reach operating temperature faster, which in turn allows full power generation capability faster. Each component of the external lubricant filtration system 318 may be coupled by a set of lubricant distribution lines 336 enabling fluid communication with an engine-driven lubricant circulation pump 172 of radial power-generation unit 100. Lubricant filtration system 318 functions as an extension of the internal engine lubricating system of radial engine 100, which may include the pressure pump 320 and scavenging pump 322, lubricant distribution lines 336, etc. Lubricant cooler 174 may include active cooling through at least one motorized fan 338 operated by at least one of a 12-volt and a 24-volt direct current (DC) source.
Upon shutdown of the radial engine 100, the scavenging portion 322 of the external lubricant treatment system begins to draw the remaining lubricant 120 out of both cavities 190, 184 of the crankcase 186. The removal of the lubricant 120 may help to reduce the volume of lubricant 120 required in the crankcase 186 during normal operation, as well as reducing the potential of flooding in the lower cylinders 140 prior to start-up. The removal of lubricant 120 helps to minimize any lubricant 120 migration into the combustion chamber of the lowest cylinders 140 after shutdown. Additionally, as discussed above, the check valves 326, 328 help to eliminate lubricant 120 from leaking past the pumps 320, 332 and into the crankcase 186.
An exemplary flow diagram of the general lubrication system 110 is illustrated in
Turning to
Specifically,
As discussed above, 17 illustrates fan cooling ducting 208. Alternatively, under certain applications, the fan cooling ducting 208 may not be economical or feasible due to the application of the system and where the footprint may be constrained. Where the cooling ducting 208 may be constrained, alternative cooling methods may be employed, such as, but not limited to, the use of liquid cooled heads and block assemblies. When using liquid cooling, a radiator (not shown) or the intercooler 162 may be utilized to cool the liquid. However, as illustrated, the use of an exemplary fan/rotor (not shown) arrangement may be described in greater detail below.
Specifically, cooling ducting 208 provides a source for the primary radial engine 100 cooling. Air may be drawn across an auxiliary fan or rotor through the cooling ducting 208 and across the plurality of cylinder heads 151. The fan/rotor may be positioned axially either forward or aft of the radial engine 100 to draw air across and around the radial engine 100. The fan/rotor may be configured as a plurality of rotary blades that are driven by at least one of an electric motor, a hydraulic motor or through a direct connection to the internal rotating assembly 153 of the radial engine 100. The cylinder heads 151 and cylinder barrel 152 may include cooling fins 154, to increase surface area for dissipating heat as air moves about the outer surface of the radial engine 100 and through at least one turbocharger 160 intercooler 162.
With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claimed invention.
Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the arts discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation and is limited only by the following claims.
All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “the,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.
