Nautilus Cycle - HCI/HCCI Achieved

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The Nautilus Cycle utilizes semi-continuous HCI/HCCI combustion with a primary/secondary piston proposal. Placing a ‘nipple” also known as the primary piston with this design on top of the regular shaped piston is what makes this concept so unique and effective during a homogenous charge compression ignition cycle. The well thought cylinder head design now consists of a ‘primary combustion chamber”. The position of the primary combustion chamber is in the center of the cylinder head, replacing where spark ignition is located in conventional SI and diesel engines. The primary piston is projected to be inserted into the reconfigured cylinder head, never making direct contact with top dead center (TDC) of the primary combustion chamber.

Conventional SI and diesel engines have their intake valves on one side of the cylinder head and the exhaust valves on the opposite site. The downfall that for such design in an HCCI engines is that this causes half of the combustion chamber to be hotter than the other, resulting in unbalanced temperatures.

The Nautilus Cycle, however, has cleverly repositioned the intake and exhaust valves diagonally and two exhaust ports opposed from each other in the cylinder head, causing balanced temperatures throughout the combustion chamber. This reconfiguration results in the elimination of rich spots within the chamber, creating a 100% lean HCI/HCCI cycle.

In the Nautilus Cycle’s cylinder head design there is a smaller intake valve implemented replacing the spark ignition in conventional SI and diesel engine. This small change now allows ambient pressure to build up in the small primary chamber causing compression on the primary piston, therefore reducing the need for in-cylinder injection.

With this new technology, we've achieved full control over the HCCI cycle in all conventional RPM ranges, loads and temperatures. This concept can be implemented into existing platforms and capable of meeting 2025 EPA regulations.



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  • Name:
    Matthew Riley
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    Matthew Riley Sina Davani
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    With over 30 years of experience in developing technologies, Matthew Riley has created a diverse repertoire of marketable skills. From research to design and development of internal combustion engines to building teams to accomplish these tasks.
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