five-stroke engine

The goal of the five-stroke engine is to achieve higher efficiency than a four-stroke engine. In order to increase efficiency, a secondary cylinder is added as an expansion processor to extract more energy from the fuel. Schmitz's concept engine uses two primary "high pressure" cylinders with standard four-stroke power cycles, in addition to a larger secondary "low pressure" expansion cylinder. The hot exhaust gas from the two primary cylinders is fed into the secondary cylinder, halving the volume of gases in the primary cylinders after combustion.

This concept is similar to that of compound steam engines, which expand steam in high pressure cylinders before exhausting it into low-pressure cylinders in order to extract more energy from the steam. In 1879, Nicolaus Otto built a 5-stroke engine which was commercially produced, but suffered from poor performance.{{Cite journal |last=Suzuki |first=Takashi |date=May 1997 |title=The Romance of Engines |url=http://dx.doi.org/10.4271/r-188 |journal= |pages=87–93 |doi=10.4271/r-188 |doi-access=free|url-access=subscription }} Two Spanish patents (ES0156621, F Jimeno-Cataneo, 1942; and ES0433850, C Ubierna-Laciana, 1975) describe 5-stroke engines identical to that of Schmitz's design, this engine had a fellowship to Burgundy University to be studied. J.W. Eisenhuth patented an 'air and gas engine' with double expansion (US640890, 1900). A car with this engine was in the Harrah Collection, though its fate after the collection was dismantled is unknown.

In Schmitz's design, the compression ratio of the low pressure expansion cylinder is adjustable to achieve an optimal expansion ratio, regardless of the primary cylinders' compression ratio. The prototype has demonstrated an approximately 10% decrease in fuel consumption over a standard gas engine.{{Cite web |url=http://www.ilmor.co.uk/capabilities/5-stroke-engine |title=Ilmor, 5 Stroke Engine |access-date=2017-01-30 |archive-date=2017-03-13 |archive-url=https://web.archive.org/web/20170313160448/http://www.ilmor.co.uk/capabilities/5-stroke-engine |url-status=dead }}[https://www.youtube.com/watch?v=u0uPmrSRM7w Five stroke engine animation]{{Cite web |url=http://www.5-stroke-engine.com/en/Prinzip.html |title=5-stroke-engine.com, The five-stroke concept – ingeniously simple, simply ingenious |access-date=2017-01-30 |archive-date=2015-08-11 |archive-url=https://web.archive.org/web/20150811193639/http://5-stroke-engine.com/en/Prinzip.html |url-status=dead }}[http://www.autoevolution.com/news/five-stroke-engine-works-and-might-enter-production-video-87083.html autoevolution.com, Five-Stroke Engine Works and Might Enter Production. 26 Sep 2014, by Gabriel Brindusescu][http://thekneeslider.com/ilmor-5-stroke-engine-700cc-turbo-3-cylinder-130-bhp/ Ilmor 5 Stroke Engine – 700cc Turbo 3 Cylinder – 130 bhp, Better Mileage, Less Weight, By Paul Crowe]

The operation of a 5-stroke SI engine is as follows:
1 – Induction
2 – Compression
3 – Power
4 – Initial exhaust/re-expansion
5 – Final exhaust

{{More citations needed|section|date=March 2024}}

Schmitz's concept was being developed by Ilmor. Ilmor's prototype, intended for motorcycle use and consisting of 2 primary cylinders and 1 secondary cylinder, uses a solid cylinder block with electrically driven oil and water pumps, two overhead camshafts with standard poppet valves, and turbocharging. Its displacement is {{Convert|700|cc|cuin|abbr=unit}} without the secondary cylinder and {{Convert|1478|cc|cuin|abbr=unit}} in total, and it can produce {{Convert|130|hp|kW|abbr=unit}} at 7,000 rpm and {{Convert|166|Nm|lbft|abbr=unit}} at 5,000 rpm.

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• Rotary engine
• Stirling engine
• Stroke (engine)
• Two- and four-stroke engines
• Two-stroke engine
• Four-stroke engine
• Six-stroke engine
• Thermodynamic cycle
• Atkinson cycle
• Miller cycle

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{{Reflist}}

• [https://www.youtube.com/watch?v=GaTj15g6L9c Four stroke engine animation]
• {{usurped|1=[https://web.archive.org/web/20170625160053/http://www.animatedpiston.com/ Detailed Engine Animations]}}
• [http://auto.howstuffworks.com/engine.htm How Car Engines Work]
• [http://www.animatedengines.com/otto.shtml Animated Engines, four stroke] {{Webarchive|url=https://web.archive.org/web/20111110171749/http://www.animatedengines.com/otto.shtml |date=2011-11-10 }}, another explanation of the four-stroke engine.
• [http://commons.wikimedia.org/wiki/File:New4stroke.gif New 4 stroke]

{{Piston engine configurations}}

{{Aircraft piston engine components}}

Category:Internal combustion piston engines