marc wiese wrote:
http://www.autoweb.com.au/start_0/showall_/id_MAZ/doc_maz0101101/article.html
A very interesting and informative write up by the designers on this
new powerplant. It explains the variable tuned intake AND exhaust!!!!
Comments following Me: are mine PL
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Unlike previous mass-production rotary engines, which employed side exhaust ports and peripheral intake ports, the naturally aspirated RENESIS has intake and exhaust ports in the side housings. This configuration eliminates overlap between the opening of the intake and exhaust ports, enhancing combustion efficiency. The intake ports are 30% larger and their timing has been changed to make them open sooner than in previous designs. Moreover, the exhaust ports open later, resulting in a longer power (expansion) stroke and providing radically improved heat efficiency.
Unlike the single peripheral port per rotor of previous designs, the RENESIS uses two exhaust ports per rotor. This produces a combined exhaust port opening area nearly twice as large and results in a substantial reduction in exhaust resistance.
The rotors have also been made lighter for better performance at high-rev levels. The rotors used in the RENESIS weigh approximately 14% less than those used in the engine that powers the RX-7, which we sell in Japan.
Me: I saw nothing about variable tuned exhaust marc.
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The increased heat efficiency resulting from zero overlap between the opening of the intake and exhaust ports makes it possible for the RENESIS to run on a leaner fuel mixture than conventional rotary engines. When idling, the RENESIS consumes 40% less fuel than the current production rotary engine.
Me: I wonder what it is at full power. MY wife says WHOPEEEE! and laughed.
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Reciprocating piston engines generally use a richer fuel mixture under high speed and high-load conditions to prevent knocking. In contrast, rotary engines do not require a particularly rich fuel mixture under these conditions due to their special
combustion characteristics. In addition, the RENESIS achieves nearly complete combustion over the entire speed range thanks to its high compression ratio and the use of new fuel injectors designed for improved fuel atomization. These enhancements allow the RENESIS to run on a leaner fuel mixture than conventional rotary engines from the low to the high-rev range. The result is the power and performance of a sports car engine and reduced fuel consumption. Low Emissions
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Instead, they [HC] are carried over and burned in the next combustion cycle, dramatically reducing emissions. In addition, air injection directed into the combustion chamber increases the efficiency of the exhaust reaction, significantly over Mazda's existing system during engine startup. Together with the double-skin exhaust manifold, the new layout makes the exhaust much hotter when it reaches the catalytic converter, speeding the converter reaction for clean emissions from the moment the engine is started.
Me: This is the first time I have heard of direct air injection into the combustion
chamber. Not easy to do. It takes a lot of compressed air to make a difference.
that takes horsepower.
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In a rotary engine, oil is supplied directly to the interior walls of the combustion chamber to lubricate the "apex" and "corner" seals. We've kept the paths which supply oil in the RENESIS as small as possible, and we have redesigned the oil supply nozzles to improve their efficiency. With these enhancements, the RENESIS consumes about half as much oil as a conventional rotary engine.
Me: I also think it has to do with a cooler apex seal.
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We want to achieve output of 250 horsepower.
Me: This number keeps getting lower. -------------------------------------------------------------------------------------------
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