US 7287494 B2
An internal combustion engine that includes individual, liquid-cooled, cylinder assemblies mounted separately to a common cylinder carrier. A modular cylinder carrier that is assembled from separate cylinder mounting modules and main bearing bulkheads.
1. An internal combustion engine, comprising:
a cylinder carrier, comprising:
a plurality of cylinder mounting modules; and
a plurality of main bearing bulkheads interposed between and interconnecting adjacent ones of said cylinder mounting modules;
a crankshaft mounted to said main bearing bulkheads, with said crankshaft having a longitudinal centerline; and
a plurality of cylinder assemblies mounted to said plurality of cylinder mounting modules, with each of said cylinder assemblies comprising:
a cylinder bore portion which does not contact any of said main bearing bulkheads;
a cylinder head having at least one intake port and at least one exhaust port;
a piston slidingly housed within said cylinder portion; and
a connecting rod mounted to said crankshaft.
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18. A method for removing and re-installing an individual cylinder assembly of an internal combustion engine, comprising the steps of:
removing a plurality of fasteners extending from a cylinder carrier upwardly through a cylinder portion and a cylinder head;
lifting said cylinder head from said engine;
lifting said cylinder portion from said engine;
removing a wrist pin and a piston mounted upon a connecting rod for reciprocation within the cylinder portion;
installing a new piston and wrist pin upon said connecting rod;
installing a new cylinder portion upon said piston by sliding a piston ring compression zone of said cylinder portion over a plurality of piston rings carried upon said piston;
seating said new cylinder portion upon a pilot diameter formed in the cylinder carrier; and
mounting said cylinder head upon said cylinder portion.
19. A method for replacing crankshaft main bearing inserts in a reciprocating internal combustion engine, comprising the steps of:
removing an oil pan mounted to structural rails at the bottom of the engine's crankcase;
removing at least one structural rail extending longitudinally along a portion of the periphery of said cylinder carrier parallel to said crankshaft centerline, with said structural rail also extending vertically from a position above the centerline of the crankshaft to said oil pan;
serially removing a plurality of main bearing caps from a cylinder carrier, while replacing the main bearing insert associated with each of said bearing caps;
reinstalling said at least one structural rail; and
reinstalling said oil pan.
The present application claims priority to U.S. Provisional Patent Applications 60/626,622 and 60/626,623, filed Nov. 10, 2004, and U.S. Provisional Patent Applications 60/658,078 and 60/658,079, filed Mar. 3, 2005, and is related to U.S. patent application Ser. No. 11/163,945 filed Nov. 4, 2005.
The present invention relates to an internal combustion engine having individual cylinder assemblies which are mounted upon a cylinder carrier. The cylinder carrier may itself be modularized. The present inventive modular structure is ideally suited to either naturally aspirated engines or engines operated at high specific output, such as turbocharged or supercharged diesel and gasoline engines.
The vast majority of multi-cylinder internal combustion engines sold today utilize a single cylinder block containing a plurality of cylinder bores. Unfortunately, if one of the cylinder bores becomes damaged to the point where it cannot be repaired by sleeving or by other means commonly used for such repairs, the entire cylinder block must be scrapped. Another drawback characterizing conventional engines resides in the engines' cooling systems. Most engines use a cooling circuit in which water is drawn into a lower portion of the engine, particularly the cylinder block, at only a single location, and then allowed to flow along the length of the cylinder block, while a portion of the water flowing along the length of the cylinder block, and eventually, all of the water, flows upwardly through the cylinder head of the engine. Then, water flows along cooling passages formed within the cylinder head and out of the engine, again at a single location. A drawback of this type of cooling system resides in the fact that the coolant must travel a fairly long path through the engine, and as a result, the coolant becomes quite heated and therefore unable to transfer as much heat as would be the case were the coolant to be introduced at a lower temperature and not forced to flow around the entire engine.
An engine according to the present invention solves the problems described above by providing a true modular construction for the power cylinders. In one embodiment, the cylinder carrier is itself modular. All of the present inventive engines utilize direct fresh water cooling, with individual cooling flows directed to each of the cylinder assemblies. In this manner, the present engine is ideally suited for charge air boosting to fairly high pressures, because the engine offers superior cooling capability as compared with prior art engines.
A liquid-cooled internal combustion engine includes a plurality of cylinder assemblies mounted individually to a common cylinder carrier. Each cylinder assembly houses a single piston and has a cylinder portion with a cylinder bore, a cylinder head with at least one intake port, and at least one exhaust port, as well as at least one self-contained cooling passage. The present engine also includes a common-rail coolant inlet manifold for introducing an individual coolant flow to each of the self-contained cooling passages within the cylinder assemblies, and an exhaust manifold assembly mounted to each of the cylinder heads, with the exhaust manifold including a plurality of branch passages for receiving exhaust from each of the exhaust ports. The exhaust manifold further includes a number of separate intake coolant passages for conducting coolant flowing from each of the self-contained cooling passages in the cylinder head about an exterior portion of a mating one of each of the exhaust manifold's branch passages.
The self-contained cooling passages in each cylinder assembly extend about the cylinder portion and cylinder head. The coolant is introduced by the coolant inlet manifold into each of the self-contained passages at a location proximate a lower portion of the cylinder portions, so that coolant is first permitted to flow about the cylinder portion, and then about the cylinder head, prior to being discharged into the exhaust manifold at a location proximate the exhaust port corresponding to the particular cylinder in question.
Coolant for the cylinders and cylinder head of the present engine is circulated by means of a primary water pump which circulates either fresh water, or a glycol and water solution, through the cylinder assemblies and then through the cylinder heads into the exhaust manifold. While in the exhaust manifold, a heat exchanger mounted within the manifold transfers heat from coolant flowing from the cylinder assemblies to raw water flowing through a heat exchanger in the exhaust manifold.
In order to achieve excellent intercooling, a liquid-cooled charge air intercooler is furnished with raw water directly by a raw water pump. Similarly, a liquid-cooled engine oil cooler is furnished with raw water directly by the raw water pump. Raw water is also furnished directly to the previously described heat exchanger situated within the exhaust manifold.
A secondary fluid cooler located downstream from the intercooler transfers heat from a secondary fluid, such as hydraulic fluid, or transmission fluid, or fuel, to raw water flowing from the intercooler.
A turbocharger ideally mounted on an engine according to the present invention includes a cooling jacket for receiving raw water flowing from the oil cooler.
According to another aspect of the present invention, a method for cooling a multi-cylinder internal combustion engine includes the steps of cooling a number of cylinder assemblies by providing an individual flow of fresh water to each of a corresponding number of discrete cooling passages. A separate, discrete cooling passage is routed to and through each of the cylinder assemblies. The present method also includes the step of extracting heat from the fresh water flowing from the cylinder assemblies by means of a direct raw water cooled heat exchanger. The present method also includes the step of extracting heat from a charge air intercooler by providing a direct raw water flow to the intercooler. Finally, the present method may include the step of extracting heat from lubricating oil flowing through the engine by means of a heat exchanger cooled by direct raw water flow.
According to another aspect of the present invention, a cylinder carrier includes a plurality of cylinder mounting modules and a plurality of main bearing bulkheads interposed between and interconnecting adjacent ones of the cylinder mounting modules. A crankshaft is mounted to the main bearing bulkheads. The mechanical strength of the cylinder carrier is enhanced by structural rails, extending longitudinally along the periphery of the cylinder carrier, parallel to the crankshaft's centerline. These structural rails extend vertically and downwardly from a position above the centerline of the crankshaft, to an oil pan.
Each of the cylinder mounting modules preferably comprises a light alloy casting, with each of the main bearing bulkheads preferably comprising a ferrous body. For example, cylinder mounting modules may be formed as aluminum castings, with the main bearing bulkheads being grey or nodular iron, cast steel or other ferrous compositions. As yet another alternative, not only the cylinder mounting modules, but also the main bearing bulkheads may be fabricated from a light alloy.
The present engine further includes a single camshaft extending parallel to the crankshaft centerline. The camshaft operates at least one intake valve and at least one exhaust valve for each of the individual cylinder heads. The camshaft operates the valves by means of at least two rocker shafts extending across an upper portion of each of the cylinder heads in a direction generally perpendicular to the crankshaft centerline.
According to another aspect of the present invention, a method for removing and reinstalling an individual cylinder assembly of an internal combustion engine includes the steps of draining coolant from the engine and removing a plurality of fasteners extending from a cylinder carrier upwardly through a cylinder portion and through a cylinder head. Thereafter, the cylinder head and cylinder portion are lifted from the engine and a wrist pin is shifted left or right within the piston so as to allow the piston to be separated from its connecting rod. Then, a new piston and wrist pin are installed upon the connecting rod and a new cylinder portion is installed upon the piston by sliding a piston ring compression zone of the cylinder portion over a plurality of piston rings carried upon the piston. Thereafter, the new cylinder portion is seated upon a pilot diameter formed in the cylinder carrier and the cylinder head is mounted upon the engine. Preferably, each of the cylinder portions has a ferrous cylinder sleeve pressed in place in the cylinder portion 18.
According to another aspect of the present invention, a method for replacing crankshaft main bearing inserts in a reciprocating internal combustion engine includes the steps of removing an oil pan mounted to structural rails of the bottom of the engine's crankcase, and then removing at least one of the structural rails extending longitudinally along a portion of a cylinder carrier parallel to the crankshaft's centerline. The structural rail also extends vertically from a position above the centerline of the crankshaft to the oil pan. After the structural rail is removed, a number of main bearing caps will be removed serially from the cylinder carrier while replacing the main bearing inserts associated with each of the bearing caps. Thereafter, the engine is completed by reinstalling the previously removed structural rail and the oil pan.
It is an advantage of an engine according to the present invention that very high turbocharger or supercharger boosting rates are sustainable without risk of engine damage because the use of direct raw water cooling of the engine lubricant, engine fresh water coolant, and charge air intercooler, coupled with the individual cylinder cooling and the exceedingly short coolant flow paths through the engine, assure that excellent heat rejection is achieved.
It is another advantage of an engine system according to the present invention that a single cylinder may be repaired without the necessity of disassembling the remaining portions of the engine. This is particularly important for engines operated at a very high specific output, such as engines installed in offshore racing vessels, because for a variety of reasons, it frequently happens that only a single cylinder will fail. Unfortunately, with conventional marine engines, such failure often necessitates disassembly of the boat to remove an engine with a single failed cylinder. This problem is obviated by an engine constructed according to the present invention.
It is yet another advantage of an engine system according to the present invention that the modularity of the engine allows engines to be produced with multiple numbers of cylinders such as two, three, four, six, eight, or more, using the structurally identical cylinder assemblies, cylinder mounting modules, and main bearing bulkheads. Those skilled in the art will further appreciate in view of this disclosure that the present engine system could be employed with vee type, or inline, or radial engines, as desired.
It is yet a further advantage of an engine and method according to the present invention that an engine rebuild, including individual cylinder water jackets, may be accomplished without the need to re-machine any component of the engine other than, in certain cases, the crankshaft.
Other advantages, as well as objects and features of the present invention, will become apparent to the reader of this specification.
As shown in
Fresh water coolant flowing from outlet ports 62 of each of cylinder heads 22 flows through ports 62A formed in exhaust manifold 74 (
Tube bundle 100 is cooled by means of a direct raw water flow provided by raw water pump 118 which is shown in
Turning now to
The third separate flow of the raw water split from the flow through raw water pump 118 flows through intercooler coil 112 (not visible), located inside intake manifold 106 which is shown in
Raw water leaving intercooler 112 passes through secondary fluid cooler 138, which is shown in
The manifold of
Details of the bottom end of the present engine are shown in
Regardless of the number of cylinders of engine 10,
Removal of main bearing inserts 176 is aided by the removability of structural rails 170 (
According to another aspect of the present invention, a method for replacing crankshaft main bearing inserts in a reciprocating internal combustion engine includes the steps of removing oil pan 174 and then removing structural rail 170 from at least one side of engine 10. Structural rail 170, oil pan 174, and cylinder carrier 30 are attached to another by means of through bolts 172 (
The present engine, whether having either a modular, or a non-modular cylinder carrier 30, permits ready removal and reinstallation of an individual cylinder assembly. Experience shows that frequently, only one cylinder of an engine may be worn excessively. All too often with mono-block engines, it becomes necessary to scrap the entire block because it is not possible to rebore the cylinder. Even if reboring is an option, in an engine application such as a pleasure boat, it is not possible to machine anything on the cylinder block without removing the engine from the boat. Such removal is extremely costly, and particularly so, in the case of boats having multiple decks above the engine room.
In contrast with prior art engines, with the present inventive engine it is possible to replace a cylinder assembly, including the piston, and, if necessary, the connecting rod, without removing the engine from a boat or other vehicle. Should removal of a marine variant of the present engine become necessary, however, the engine may be removed without the necessity of cutting an access hole in either the decks or hull of a boat, because once cylinder heads 22 and cylinder portions 18, as well as pistons 32, and connecting rods 40 have been removed from the engine, along with structural rails 170, oil pan 174, and crankshaft 166, and other small components, carrier 30 may be removed without the need for lifting equipment, which is generally unavailable belowdecks in most boats.
If it becomes necessary to remove and reinstall an individual cylinder assembly 16 of engine 10 according to the present invention, the steps for such removal and reinstallation include draining coolant from engine 10, removing a plurality of fasteners 172 extending from cylinder carrier 30 upwardly through cylinder portion 18 and cylinder heads 2, and lifting cylinder head 22 and cylinder portion 18 from carrier 30. Then, wrist pin 36 may be removed and a new piston, 32, installed upon connecting rod 40. Thereafter, cylinder portion 18 may be slidably installed upon piston 32 by sliding piston ring compression zone 178 of cylinder bore (
While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.
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