Abstract: It is common in heating systems, such as in a hot water heater for there to be a combustor with the exhaust gases from the combustor provided to a heat exchanger to heat up the water. Disclosed herein is an integrated heat exchanger and burner assembly in which the combustion occurs proximate the surface of the heat exchanger. Such a system may include at least one tube that is coiled into a number of turns, that is a tube coil with the at least one tube having an inlet and an outlet and the distance between adjacent turns is less than a predetermined distance, i.e. a the quench distance.

Abstract: Newly-developed manufacturing techniques have opened up new possibilities in fabricating designs of components that were previously infeasible. One such component is a heat exchanger. A crossflow heat exchanger is disclosed that includes a plurality of internal passages for conducting a first fluid. The internal passages that form a spiral with adjacent passages separated by a gap of a predetermined distance or less. The second fluid passes through the gaps. The internal passages may be a plurality of parallel passages arranged along a first line. From upstream to downstream, each of the passages form an inlet spiral connected to an inner ring connected to an outlet spiral. The gaps are less than a predetermined distance related to a Reynolds number that is less than that at which laminar flow exists.

Abstract: In some two-stroke engines, a stationary ring is disposed in a groove in the cylinder liner. However, it is a challenge to install such a stationary ring while maintaining a narrow gap to minimize gas flow through the gap. A ring system for an internal combustion engine is disclosed that includes an L-shaped, split ring with a reentrant angle and a nested, split ring with a convex quadrilateral cross section nested with the L-shaped ring proximate the reentrant angle. The two rings are affixed so that the two gaps of the split rings cannot align. Or, in other embodiments, the two are allowed to rotate relative to each other over a predetermined angle.

Abstract: A toroidal combustion chamber shape with side injectors is being developed for an opposed-piston engine. Favorable combustion characteristics of such configuration are transferred to a conventional engine, i.e., one with a combustion chamber delimited by a piston, a cylinder wall, and a cylinder head. At least one injector is disposed in the cylinder head at the periphery. The fuel is injected substantially along the plane of interface between the cylinder head and the cylinder block. The intake system is configured to provide a swirling flow in the combustion chamber. The fuel is injected in an angle that is displaced from the central axis of the cylinder and directed along the swirl. In some embodiments, a substantially torus-shaped volume is formed between the piston and the cylinder head when the piston is at top center. The injector or injectors spray fuel into the toroidally-shaped volume substantially tangent to the torus.

Abstract: A disclosed lubrication system for an internal combustion engine includes an inertia reactive oil injector in a piston that reacts to convey lubricating oil to the space between the piston and its adjacent cylinder wall immediately below the upper piston rings as the piston reaches top dead center. A first embodiment utilizes a passage and reservoir formed beneath the piston wall with inlet and outlet ports at each end. The oil injector carries the oil past the intake/exhaust ports of the cylinder until the piston decelerates while approaching its TDC position. During that deceleration, the oil carried by the injector reservoir is delivered through the outlet port into the space between the piston and the cylinder liner. A second embodiment utilizes a groove of predetermined length formed in the outer surface of the piston. A reservoir is formed in the groove and defines inlet and outlet ports at each end.

Abstract: A four-process cycle is disclosed for a Vuilleumier heat pump that has mechatronically-controlled displacers. Vuilleumier heat pumps that use a crank to drive the displacers have been previously developed. However, mechatronic controls provides a greater degree of freedom to control the displacers. The four-process cycle provides a higher coefficient of performance than prior cycles in the crank-driven Vuilleumier heat pump and those previously disclosed for a mechatronically-driven Vuilleumier heat pump.

Abstract: An internal combustion engine includes a crankshaft having a first web portion defining an inner opening and defining an undercut proximate the inner opening, a second web portion defining an inner opening and defining an undercut proximate the inner opening and an inner bearing portion that engages with the inner opening of the first web portion and with the inner opening of the second web portion. First and second pushrods each have a piston end and a crankshaft end. The crankshaft ends of the first and second pushrods each have a concave surface placed over different portions of the inner bearing portion between the first and second web portions, and each further have shoulders adjacent their respective concave surface that engage with the undercuts of the first and second web portions.

Abstract: A system for recovering water from exhaust gasses, including a chamber having a first section for diverting and cooling a portion of the exhaust gases, and a second section for removing drinking water from the cooled gases. The first section slows down the flow rate of the diverted portion of exhaust gases and includes spaced apart helical tubes through which is passed a cooling fluid. The second section includes spaced apart helical tubes having a fluid permeable sidewall for travel of water from the exhaust gasses into the interior of the tubes of the second section. The tubes of the second section are coated on the exterior thereof with a porous material that promotes migration of drinking water from the exterior to the interior of the tubes.

Abstract: A Vuilleumier heat pump is disclosed in which the hot and cold displacers are disposed with a cylinder wall and an annular space outside the cylinder wall and inside the outer housing has at least one heat exchanger disposed therein. Any volume in the annular space is dead volume. A compact, effective heat exchanger is disclosed that facilitates reducing the dead volume. The heat exchanger is substantially helical with tubes that have a cross section that have a length in the direction of flow between adjacent tubes greater than a length perpendicular to the direction of flow.

Abstract: Substituting a solar concentrator for a conventional burner for heating is desirable. However, the sun's energy is diurnal and cannot be counted upon even during daylight hours. To ensure heating is available, a backup conventional combustor can be provided. According to the present disclosure, a heat exchanger element of the heater assembly is directly acted upon by solar rays via a solar concentrator and by combustion. The heat exchanger acts as the combustion holder. Fuel provided to the outside of the heat exchanger is adjusted based on the demanded for heating and the amount of insolation achieved via the solar concentrator. The heat exchanger can be part of a conventional heater or a heat pump for heating water.

Abstract: In two-stroke engines, it is common to provide two compression rings on the piston and an additional oil ring. The oil ring can be on the piston, but yields a longer piston. Alternatively, the oil ring is placed in a circumferential groove in the cylinder liner. One problem with such a configuration is that the compression rings move with respect to the oil ring and the annular volume between the two is compressed during reciprocation of the piston, which can cause pumping of oil into the ports. According to embodiments of the present disclosure, axial slots are formed in the cylinder liner that extends from the circumferential groove toward the ports extending along the bridges and beyond the ports. This provides a vent for the annular volume to avoid pumping the oil into the ports.

Abstract: An opposed-piston, opposed-cylinder engine is disclosed that has the pistons symmetrically arranged in the opposed cylinders. In one embodiment, the inner pistons are exhaust pistons and the outer pistons are intake pistons. Alternatively, the inner pistons are intake pistons and the outer pistons are exhaust pistons. The pistons are coupled to the crankshaft that is situated between the opposed cylinders. Central axes of the two cylinders are offset by a predetermined distance. The connecting rods that couple between the crankshaft and the pistons are arranged adjacent to each other on journals of the crankshaft. The journal to which the pushrods couple is not a split-pin type. Instead, it is one that has a common central axis. Furthermore, the crankshaft is a one-piece or unitary structure.

Abstract: Reciprocating motion can be converted to rotary motion through a crankshaft and a connecting rod. In a connecting rod that is primarily in compression, two opposing connecting rods can be coupled to a single journal. Two bearing shell portions are placed over the journal with a pushrod placed over each bearing shell portion. The pushrods are normally in compression. To overcome the potentiality of the pushrods briefly being in tension, retainers can be coupled to the pushrods. Because both pushrods are coupled in-line, the width of the journal that can accommodate these pushrods is shorter than for a journal on which the two pushrods are side by side. The crankshaft can be shorter, stronger, and lighter weight.

Abstract: A piston coupled to a crankshaft via pullrods presents challenges for coupling the piston to the crankshaft because the connections are provided outside the piston. A bridge is coupled to a piston skirt at the end of the piston away from the piston crown. The bridge structure includes: a central support structure, a first projection extending outwardly from the central support structure in a first radial direction, and a second projection extending outwardly from the central support structure in a second radial direction. The central support structure is substantially hollow with a series of internal braces to yield a lightweight piston.

Abstract: Two-stroke engines are particularly prone to piston scuffing due to insufficient oil at some operating conditions. A system and method to precisely deliver oil is disclosed. An oil reservoir groove is formed in the piston with an oil reservoir ring welded to the surface of the piston. A cavity behind the ring forms an oil reservoir. The ring has an inlet gap. The cylinder wall has an oil injector installed therein which sprays oil into the inlet gap when the inlet gap is proximate the oil injector tip. An electronic control unit commands the quantity of oil to provide to the oil reservoir, with the quantity and timing of the injections based on the operating conditions of the engine.

Abstract: A Vuilleumier heat pump is disclosed in which hot and cold displacers are controlled by first and second electromagnetic actuators, respectively. The first actuator is capable of moving the hot displacer between the first and second ends of travel while the cold displacer remains stationary and the second actuator is capable of moving the cold displacer while the hot displacer remains stationary. Prior art crank arrangements are unable to provide dwell in one displacer while moving the other displacer. Actuation of the displacers according to embodiments of the present disclosure provides a higher coefficient of performance than crank arrangements.

Abstract: By providing an electrically-controlled turbocharger (ECT) on a compression-ignition (CI) engine, the engine can be provided a desired lambda and a desired EGR fraction over the range of operating conditions. When lambda in the exhaust is leaner than the desired lambda, electrical energy to the electric motor of the ECT is reduced to bring actual lambda to desired lambda. Analogously, when lambda in the exhaust is richer than the desired lambda, electrical energy to the ECT is increased.

Abstract: It is important to maintain the temperature in the ring pack area of the piston of an internal combustion engine below about 270° C. to maintain proper ring function and lubrication. Disclosed is a piston with a heat barrier groove between the piston top and the ring pack and a method to construct such a piston. The heat barrier groove extends inwardly toward the center of the piston a greater distance than the compression ring grooves. In one embodiment, a low thermal conductivity material is placed in the inner portion of the heat barrier groove and a split ring is place in the outer portion. In another embodiment, a gas is provided in the inner portion and the split ring is welded to the piston so that the inner portion of the heat barrier groove is sealed, i.e., welding at the upper and lower edges and at the gap.

Abstract: In a piston-ported engine, a sealing ring may be placed in a groove in the cylinder. As the groove is of greater diameter than the cylinder, the sealing ring overlaps into a helix allowing it to be enter the cylinder. However, such a helix does not fit into a groove without when in the helix. Alternatively, a shorter sealing ring is placed into the groove. However, the gap is too large. According to one embodiment, a groove of double the width of the ring is provided and the helical ring is installed and caused to unwind in the groove so that the ring sits in a plane. A spacer ring is placed in the groove to fill the extra space in the groove. An elastomeric material or a tension spring in an outer groove in the sealing ring can be used to cause the ring to press against the piston.

Abstract: In some two-stroke engines, a stationary ring is disposed in a groove in the cylinder liner. However, it is a challenge to install such a stationary ring while maintaining a narrow gap to minimize gas flow through the gap. A ring system for an internal combustion engine is disclosed that includes an L-shaped, split ring with a reentrant angle and a nested, split ring with a convex quadrilateral cross section nested with the L-shaped ring proximate the reentrant angle. The two rings are affixed so that the two gaps of the split rings cannot align. Or, in other embodiments, the two are allowed to rotate relative to each other over a predetermined angle.