SBIR-STTR Award

This proposed Phase I effort seeks to advance, and demonstrate feasibility of, a patent-pending technology design to address engine-related concerns in small generators as experienced by the Marine Corps and others. The Marine Corps states that small military generators frequently operate at low loads (below maximum mission profile load) and experience wet-stacking and low thermal efficiency. In addition to addressing these issues, the Marine Corps has also expressed its desire to achieve lower emissions and operational capability across a variety of fuels including diesel and JP-8. These areas can be addressed with an innovative concept to modify a 4-cycle engine into a 6-cycle continuous combustion engine. This system uses the piston/cylinder assembly and a unique valve strategy to compress air, transfer air to an insulated combustion chamber, and transfer the high pressure gases back to the piston/cylinder for power extraction. With load following controls, lower emissions, and the complete combustion of fuel inherent within this proposed engine system, Phase I will evaluate the system feasibility through comprehensive thermodynamic analysis, analysis of thermal and pressure losses associated with valve design, and determining design boundaries of the insulated combustion chamber to achieve enhanced combustion without compromising system life or thermal efficiency.

Benefit:
The 6-stroke Continuous Combustion Engine System offers significant potential benefits for the Marine Corps and the commercial utility engine market over conventional 4-stroke. Continuous combustion in an insulated combustion chamber eliminates wet-stacking, improves engine fuel efficiency, and allows for the use of many types of fuels including diesel, JP-8, alcohol, and bio-diesel. Complete combustion of fuels results in low emissions which are not adversely affected by sulfur containing fuels. The larger expansion ratio also produces less noise and a smaller heat foot print. In addition the K6 is designed as a modification to existing 4-stroke engine technology which enhances its adoption and marketability into a global market.

Keywords:
Wet-Stacking, Wet-Stacking, Load, Fuel Efficiency, following, Recycling Unburned Fuel, low emissions, flex-fuel, Durability

The proposed Phase II program seeks to demonstrate the feasibility of a patent-pending 6-cycle continuous combustion engine system technology that is a modification of existing 4-cycle engines to address engine related concerns in small generators as experienced by the United States Marine Corps and others. Concerns include wet-stacking, low efficiency at low loads, improved emissions capabilities (especially high sulfur fuels), and improved mulit-fuel capability. Phase I analysis showed promising results of thermodynamic efficiency, addressing the MC concerns, and in solving the technical challenges of the 6-cycle system. The Phase II program is in two parts: (1) design and develop a Proof-of-Concept operational prototype for demonstration and preliminary data collection by modifying the existing 4-cycle Yanmar diesel engine to demonstrate the potential capability of the 6-cycle system and for demonstration to potential engine manufacturers, and (2) improve the design to optimize engine performance to meet MC performance targets and to achieve a 100 hour operational capability. Additional focus will be placed on cost effective manufacturability of the components that are new for converting a 4-cycle engine to a 6-cycle engine for future commercialization.

Benefit:
The 6-cycle engine system offers very wide flexible fuel capability including diesel, JP fuels, alcohol, gasoline, even mixtures of fuels. The energy content is the primary consideration. The engine is insensitive to other fuel properties. Continuous combustion in an insulated combustion chamber offers both complete controllable combustion and low emissions. Engine efficiency can be equivalent of better to existing similar 4-cycle diesel engines. There are further theoretical thermodynamic efficiency improvements once the 6-cycle concept is proven. Wet-stacking for small engines is eliminated due to long combustion times and continuous combustion. The 6-cycle is a modification of a 4-cycle engine; 80% of parts remain the same. Utility engines in 4-30 kW range are initial commercial applications.

Keywords:
Multi-fuel, flex-fuel, Wet-Stacking, efficiency, low emissions