| Methods and apparatus to use engine valves as both intake and exhaust valves -> Monitor Keywords |
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Methods and apparatus to use engine valves as both intake and exhaust valvesRelated Patent Categories: Internal-combustion Engines, Poppet Valve Operating Mechanism, Hydraulic SystemMethods and apparatus to use engine valves as both intake and exhaust valves description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070215078, Methods and apparatus to use engine valves as both intake and exhaust valves. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/775,387 filed Feb. 21, 2006. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to the field of the operation and control of engine valves in piston engines. [0004] 2. Prior Art [0005] The present invention is based on the fact that at higher engine speeds and higher power outputs, engines have more difficulty breathing, that is, their volumetric efficiency goes down. Typically modern engines may include, by way of example, two intake valves and two exhaust valves per cylinder to attempt to increase the volumetric efficiency. However, there is a limit as to how much this can achieve, as all four valves must generally fall within a circle of a diameter approximately equal to the piston diameter. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 is a schematic cross-section through an engine head illustrating one embodiment of the present invention. [0007] FIG. 2 is an embodiment similar to that of FIG. 1, but using return springs for the air switch valves. [0008] FIG. 3 is a top schematic view of the exemplary assembly of FIG. 1. [0009] FIG. 4 is a cross section of an embodiment using poppet valves for the air switch valves, and corresponds to a cross section taken along line A-A of FIG. 3. [0010] FIG. 5 is another cross section of the embodiment of FIG. 4, though corresponding to a cross section taken along line B-B of FIG. 3. [0011] FIG. 6 is a schematic diagram for a V-6 engine incorporating the present invention. [0012] FIG. 7 is a block diagram schematically illustrating the incorporation of the present invention in a multi-cylinder engine. [0013] FIG. 8 is a block diagram of a multi-cylinder engine incorporating an embodiment of the present invention, together with a fuel injector per cylinder, and a multi-cylinder engine controller. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0014] The preferred embodiments of the present invention are intended to be used on diesel engines, though this is not a limitation of the invention, as the invention is also applicable to gasoline engines, or engines intended to operate on other fuels. Also, while the present invention is preferably to be used on turbocharged engines, this too is not a limitation of the invention, as the present invention is also applicable to non-turbocharged engines. Further, the preferred embodiments are intended to be used on engines having multiple intake and multiple exhaust valves, as is characteristic of most modern engines, though this too is a preference, not a limitation of the invention. [0015] The present invention is intended to increase the volumetric efficiency of engines, in the exemplary embodiments disclosed herein, engines having two intake valves and two exhaust valves per cylinder, by selectively using all four valves, the two intake and the two exhaust valves, as both the intake valves and as the exhaust valves for that cylinder. For this purpose, much larger valves external to each combustion chamber are used to switch the coupling of the valves (intake and exhaust) between an intake manifold and an exhaust manifold. Thus the intake valves may be coupled as intake valves or exhaust valves, depending on whether it is an intake stroke or an exhaust stroke. Similarly, the exhaust valves may be coupled between the exhaust manifold and the intake manifold, depending on whether they are then currently functioning as exhaust valves or intake valves. Because these external valves can be large, they can be made to have low flow resistance, with the net result providing much better intake and exhaust breathing for the engine. [0016] The preferred embodiments of the invention are intended to be used in what are referred to as camless engines, wherein the timing and operation of the engine valves may be electronically controlled (see for instance, U.S. Pat. No. 6,739,293 entitled Hydraulic Valve Actuation Systems and Methods, the disclosure of which is hereby incorporated herein by reference). While the preferred embodiments use electronically controlled hydraulic valve actuation, other types of camless engine engine valve operation could equally as well be used. Because of that degree of control, an engine such as a diesel engine may be operated as a four cycle engine, or for higher power output, switched to two cycle operation, as desired. Consequently, in a typical application of the present invention, a diesel engine may be operated as a conventional four stroke engine using two intake valves and two exhaust valves at idle and at low engine outputs, at higher engine speeds and outputs, perhaps operated with all valves functioning as both intake and exhaust valves as described, and at still higher engine outputs operating as a two stroke engine, again with all valves functioning as both intake and exhaust valves as described. This is merely one example of the combinations of operating modes possible with the present invention. [0017] FIG. 1 presents a schematic cross-section through an engine head showing a block 20, a piston 22 and two engine valves 24. These two engine valves could be either two intake valves or two exhaust valves on the respective cylinder, with two such assemblies being used per cylinder in this example. Two two-way air switch valves 26 and 28 are shown, operated by electronically controlled hydraulic actuators 30 and 32 at the top of the Figure, with return pins 34 and 36 at the bottom being always subjected to hydraulic pressure for return of the air switch valves to the upper position when the hydraulic actuators 30 and/or 32 at the top of the air switch valves 26 and 28 are not pressurized. At the left side is the intake manifold INT and on the right side is the exhaust manifold EXH. These manifolds would be common to all cylinders of a multi-cylinder engine. [0018] In FIG. 1, the right-hand air switch valve 28 is in its upper position, preventing flow from the engine valves 24, when open, to the exhaust manifold EXH. At the same time, the air switch valve 26 at the left of the Figure is in its lower position, allowing flow past the engine valves 24, when open, from the intake manifold INT to the cylinder. Thus the two engine valves 24 shown, with the air switch valves 26 and 28 in the position illustrated, function as intake valves. However, if the air switch valves 26 and 28 are reversed in position, the two engine valves 24 shown would function as exhaust valves. [0019] The hydraulic control valves for the hydraulically controlled engine valves and switch valves in this embodiment are shown schematically at the top of FIG. 1. Hydraulic control valve HVA1 controls the two engine valves 24 for the cylinder shown, with hydraulic control valve HVA2 controlling the other two engine valves for that cylinder, not shown. Hydraulic control valves SW1 and SW2 control the switch valves 26 and 28 for the two engine valves 24 for the cylinder shown, with hydraulic control valves SW3 and SW4 controlling the other two switch valves for the other two engine valves for that cylinder, not shown. Also in this embodiment, an intensifier-type fuel injector may be used, such as one having direct needle control, and a selection of one, a second, or both intensifier actuation piston areas to provide respective intensified fuel pressures for injection, as controlled by control valves INJ1, INJ2 and INJ3. FIG. 2 is an embodiment similar to that of FIG. 1, but using return springs 42 for the air switch valves 26 and 28. [0020] A top schematic view of the exemplary assembly of FIG. 1 is illustrated in FIG. 3. Two engine valves 24 are operated in unison by a single actuator 40 (FIGS. 1 and 2) controlled by control valve HVA1 as a result of the BRIDGE shown in FIG. 1 and as illustrated in FIG. 3 as vertical dashed lines extending between two engine valves 24. The larger circles are the associated air switch valves 26 and 28. While in FIG. 1 the air switch valves 26 and 28 are shown as a form of spool/poppet valve, any type of valve of adequate speed could be used. In that regard, note that these valves are not subjected to substantial pressure differentials, and accordingly, relatively simple valves of various configurations could be used, including but not limited to rotary valves. Also, while two, two way valves are shown, a three-way valve could be used if desired. Continue reading about Methods and apparatus to use engine valves as both intake and exhaust valves... Full patent description for Methods and apparatus to use engine valves as both intake and exhaust valves Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Methods and apparatus to use engine valves as both intake and exhaust valves patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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