Split cycle engine
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This article contains information about scheduled or expected Category:Proposed engine designs. It may contain preliminary or speculative information, and may not reflect the final specification of the product. |
The split cycle engine is a type of internal combustion engine.
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[edit] Design
In a conventional otto cycle engine, each cylinder performs four strokes per cycle: intake, compression, power, and exhaust. This means that two revolutions of the crankshaft are required for each power stroke. The split-cycle engine divides these four strokes between two paired cylinders: one for intake/compression and another for power/exhaust. Compressed air is transferred from the compression cylinder to the power cylinder through a crossover passage. Fuel is then injected and fired to produce the power stroke.
In a standard Otto cycle engine, the pistons fire every other revolution. In essence this is a conventional two stroke cycle, using a displacer piston in an accompanying cylinder to provide scavenging air for the combustion chamber (the ignition cylinder of a split-cycle design fires every revolution, however, the displacer cylinder has no power stroke, meaning that for the same number of total cylinders, this engine has the same number of power strokes per revolution as a conventional 4-cycle engine). Conventional two stroke engines do this scavenging by using crankcase compression, eliminating the need for a second piston and cylinder. Firing after top dead center also increases crankshaft torque[citation needed]. [1]. The engine is being developed in Springfield Massachusetts by the Scuderi Group LLC [2]
An animation of the engine's operation can be seen here.
[edit] History
The Backus Water Motor Company of Newark, New Jersey was producing an early example of a split cycle engine as far back as 1891.
The engine, of "a modified A form, with the crank-shaft at the top", was water-cooled and consisted of one working cylinder and one compressing cylinder of equal size and utilized a Hot-tube ignitor system. It was produced in sizes ranging from 1/2 to 3 horsepower and the company had plans to offer a scaled-up version capable of 25 horsepower or more. [3]
The Twingle engine is a two stroke engine that also uses a displacer piston to provide the air for use in the power cylinder. This was patented in 1912.
[edit] Captive Pulse Engine
Captive Pulse engines include smoothbore two-stroke engines[dubious ]. Engines of this type often utilize a reciprocating supercharger. Some Captive Pulse engines operate with forced induction at minimum displacement volume. There are also Captive Pulse engines that operate with forced induction at decreasing displacement volume[citation needed]. One particularly interesting variation is normally aspirated, but still operates as a smoothbore two-stroke. Development of this engine family began in the mid 1980's. The historical timeline is described in a 2007 K-7 engine proposal made to the Arrow Engine Company of Tulsa, Oklahoma. Two-stroke Captive Pulse engines are an evolution of Totally Captive Pulse machinery. The original Captive Pulse machines are mono-stroke, or continuous stroke engines[citation needed]. These may produce force throughout 100% of piston movement[citation needed]. The engines were invented by Thomas Allen Graves[citation needed]. They have been described in several technical writings, and U.S. provisional patent applications, including; CAPTIVE PULSE MOTOR, #710200301. Captive Pulse engines are the first smoothbore engines to utilize a true reciprocating supercharger. The engines were also developed and demonstrated by the former American Magnadyne Company of Austin, Texas[dubious ].The latest Captive Pulse engine is being combined with a high speed boat hull (U.S. patent #4,193,369) invented by Carlos Talamantes Jr. Compressive detonation and spark ignited variations have been operated. Captive Pulse is practically the most powerful per unit displacement reciprocating engine science to ever exist[citation needed]. Some versions make near absolute use of a combustion pulse, and operate with a totally sealed working volume except at top dead center. Explosion efficiency in excess of 90% has been demonstrated[citation needed]. These demonstrations were witnessed be many people and examined by David Wiser, thermodynamics engineer; Chatleff Controls, Buda Texas as early as 2001.
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[edit] References
- ^ The Split Cycle Process
- ^ Scuderi Group
- ^ The Backus Gas Engine --- Reprint of a January 15, 1891 American Machinist article
[edit] See also
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