Exemplary embodiments of the present invention relate generally to improvements to a lubrication and cooling system for use in multi-cylinder internal combustion engines.
The design and production of high performance internal combustion engines is an extremely competitive industry. Designers and builders of such engines look for every improvement possible in order to provide an edge over their competitors. Equally concerned are the consumers who purchase these engines. These purchasers are generally looking for a combination of performance and reliability that allows the purchaser to obtain the best possible combination of such qualities according to their needs. Therefore, improvements that may increase output horsepower, improve performance characteristics, improve reliability, or reduce the difficulty of building and maintaining such engines are of great value to designers, builders, and consumers alike.
High performance internal combustion engines generally have more than one combustion chamber (cylinder). In fact, to a practical limit, greater numbers of cylinders improves engine performance by allowing improved cylinder geometry for larger displacement engines and more even delivery of power throughout the rotation of an engine crankshaft. As is well known, all other variables being equal, a larger engine displacement is capable of producing more power than a lesser displacement. Thus, increasing the number of cylinders may allow an engine designer to optimize such characteristics as piston diameter and stroke, while maintaining a larger total displacement. This enables the designer to produce an engine having desired characteristics such as quick response to throttle inputs, improved torque production, or higher RPM capability.
Multi-cylinder engines are generally configured according to several known configurations where the cylinders are arranged in sets commonly referred to as “banks.” In a typical embodiment, each bank is comprised of two or more cylinders arranged along a crankshaft. Example configurations may be a single bank consisting of a plurality of cylinders (an “in-line” engine) or cylinders arranged in multiple banks (generally two), each comprising a plurality of cylinders. These banks may be arranged at an angle radially from the crankshaft of the engine. Where the cylinder banks are arranged at an angle of less than 180 degrees, the engine is commonly referred to as a “V” configured engine. Such engines are generally also referred to according the number of cylinders embodied in the engine design. For example an eight cylinder engine may be referred to as a “V8”, a ten cylinder engine a “V10”, a sixteen cylinder engine a “V16” and so forth. One skilled in the art, after examining the invention disclosed herein will understand that certain embodiments of the invention may be applied to internal combustion engine configurations other than “V” configurations. For example, without limitation, embodiments of the invention may be implemented in single bank engines and also engines in which the banks are arranged in other than the described “V” shape.
Internal combustion engines generally must be provided with some method of lubrication and cooling in order to function reliably for more than a short time. One of the difficulties encountered in the design of reliable, high power output, multi-cylinder engines is the consistent delivery of lubrication and cooling through the various cylinders. Known multi-cylinder engine designs are configured such that lubricating oil and cooling fluid is introduced to the cylinder banks at one end of the bank and circulated from that end to the opposite end of the cylinder bank in various passageways. As the number of cylinders in a bank increases, the requirement of additional passageways causes the pressure and volume of lubricating oil to be reduced for each successive cylinder of the bank. The result is that the cylinders farthest from the source of oil may be subjected to increased wear and lesser reliability. In the case of cooling fluid, the fluid may absorb heat from each cylinder as the fluid moves past the cylinder. With each cylinder, the fluid becomes increasingly hotter and is thus less able to absorb heat. As a result, the last cylinder in the path of cooling fluid may receive less cooling than those cylinders earlier in the path of the cooling fluid.
What is needed is an improved engine design that permits consistent delivery of both lubrication and cooling to multi-cylinder engine designs. In an embodiment of the invention, a multi cylinder engine may be formed such that an additional space is provided at the mid-point of a cylinder bank. In such embodiments, this additional space may be used to introduce lubricating oil at a point mid-way along the cylinder bank. Such an embodiment may reduce the number of cylinders along a lubricating oil path by creating shorter parallel paths, rather than one longer path before the lubricating oil is allowed to drain to a collection point for re-pressurization and re-delivery to the engine.
An embodiment of the invention may deliver cooling fluid at a point mid-way along the cylinder bank. Such a delivery location may allow a flow of the fluid to collect heat from a reduced number of cylinders before being channeled to a heat exchanger which reduces the temperature of the cooling fluid before re-delivery to the engine. In other embodiments of the invention, lubricating oil may be collected in a central valley between banks of cylinders and allowed to drain from the valley through the additional space directly to a collection point. This differs from known designs in which the lubricating oil drains from a plurality of locations which allow the lubricating oil to make contact with moving portions of the engine such as the crankshaft and connecting rods. Such contact causes the lubricating oil to be thrown and agitated by these moving portions. Such throwing and agitations absorbs engine power that could otherwise be delivered by the crankshaft of the engine. Agitation may also introduce air bubbles into the lubricating oil which reduces its lubricating effectiveness. In addition to oil agitation by moving engine parts such as the crankshaft, the return flow of oil may be disrupted by engine movement. In an embodiment of the invention, an oil guide may be positioned at certain points of the engine to contain and direct a flow of oil to a central collection point.
In certain embodiments of the invention, an additional space located at the mid-point of a cylinder bank may allow the use of cylinder heads designed for conventional engines to be used in combination across a bank of cylinders.
Further features and advantages of the devices and systems disclosed herein, as well as the structure and operation of various aspects of the present disclosure, are described in detail below with reference to the accompanying figures.
In addition to the features mentioned above, other aspects of the present invention will be readily apparent from the following descriptions of the drawings and exemplary embodiments, wherein like reference numerals across the several views refer to identical or equivalent features, and wherein:
Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, specific details such as detailed configuration and components are merely provided to assist the overall understanding of these embodiments of the present invention. Therefore, it should be apparent to those skilled in the art that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
As was noted above, internal combustion engines are generally comprised of a plurality of combustion chambers, commonly referred to as cylinders. In multiple cylinder engines, these cylinders are arranged adjacent to one another in configurations referred to as banks. An illustration of a bank of cylinders is shown in
Exemplary cooling of a sixteen-cylinder engine block 1400 is illustrated at
More specifically, a first flow of coolant 1414 may enter a first cylinder bank 1416 at a first supply channel. The first supply channel may be located between the middlemost cylinders 1402 and 1404 of the first bank of cylinders 1416. A first portion of the first flow of coolant 1414 may travel about each of four cylinders 1402 in a first group of cylinders. The first portion of the first flow of the coolant 1414 may return to the first supply channel to exit the engine block 1400. A second portion of the of the first flow of coolant 1414 may travel about each of four cylinders 1404 in a second group of cylinders. The second supply channel may be located between the middlemost cylinders 1406 and 1408 of the second bank of cylinders 1418. The second portion of the first flow of the coolant 1414 may return to the first supply channel to exit the engine block 1400.
A second flow of coolant 1414 may enter a second cylinder bank 1418 at a second supply channel. A first portion of the second flow of coolant 1414 may travel about each of four cylinders 1406 in a third group of cylinders. The first portion of the second flow of the coolant 1414 may return to the second supply channel to exit the engine block 1400. A second portion of the of the second flow of coolant 1414 may travel about each of four cylinders 1408 in a fourth group of cylinders. The second portion of the second flow of the coolant 1414 may return to the second supply channel to exit the engine block 1400.
When describing the lubrication systems of internal combustion engines herein, references to lower engine lubrication are intended to refer to lubrication of the crankshaft and connecting rod portions of the engine. References to upper engine lubrication refer to lubrication of those components located in the upper portions of conventionally mounted engines. Engine components which are located in the upper portions of an engine may comprise camshafts, valve lifters, pushrods, and rocker arms (if an engine is configured to utilize these components). As one ordinarily skilled in the art will understand, in known embodiments, the upper portion of a cylinder bank may receive its lubricating oil from a single inlet where the inlet is located at an end of the bank of cylinders. Such a configuration may result in a loss of pressure and oil flow as the oil moves from the inlet across the bank of cylinders. This loss of pressure and oil flow may result in suboptimal lubrication of upper engine components. Such a condition may result in increased engine wear, increased operating temperature and premature engine failure.
In an embodiment of the invention, a lubricating oil inlet may be positioned centrally in a cylinder bank. Referring to
Referring to
Referring to
In certain embodiments of the invention, the central oil returns described above may be directed to a dedicated input of a scavenge pump for delivery to an oil storage tank. Referring to
Many high performance engines are used in applications subject to sudden acceleration along various axes. Without limitation, an example application that introduces such sudden accelerations may be offshore powerboat racing. In such an application, the powerboat (along with an engine mounted in the powerboat) is subject to repeated buffeting as the result of a water surface that is less than smooth. In such applications, unpressurized lubricating oil is ideally removed from the engine after use and stored remotely from the engine crankcase until it is pressurized and re-introduced to the engine. Such remote storage, commonly referred to as a “dry sump”, provides a lubrication system that is less susceptible to buffeting and g-forces which can cause irregular oil delivery to critical engine components.
In an embodiment of the present invention, a further improvement may be realized by the introduction of an oil return guide system. As is illustrated in
As was described above, in certain embodiments of the invention, passageways may be formed at the midpoint of a cylinder bank. Such a passageway may have the additional benefit of creating an additional space between adjacent cylinders. An example of such an embodiment is illustrated in
After reading this description, one ordinarily skilled in the art will realize that the described embodiments may be applied to any number of cylinders per bank. Thus, the invention should not be construed as being limited to number of cylinders illustrated in the referenced figures or expressly described herein. Any embodiment of the present invention may include any of the optional or preferred features of the other embodiments of the present invention. The exemplary embodiments herein disclosed are not intended to be exhaustive or to unnecessarily limit the scope of the invention. The exemplary embodiments were chosen and described in order to explain the principles of the present invention so that others skilled in the art may practice the invention. Having shown and described exemplary embodiments of the present invention, those skilled in the art will realize that many variations and modifications may be made to the described invention. Many of those variations and modifications will provide the same result and fall within the spirit of the claimed invention. It is the intention, therefore, to limit the invention only as indicated by the scope of the claims.
This application claims priority to provisional application 62/173,516 filed on Jun. 10, 2015 and is incorporated by reference in its entirety as if fully recited herein.
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