Compact Efficient Rotary Diesel X-Engine 5 kW Generator Set
Award last edited on: 9/2/2022

Sponsored Program
Awarding Agency
DOD : Army
Total Award Amount
Award Phase
Solicitation Topic Code
Principal Investigator
Alexander Shkolnik

Company Information

LiquidPiston Inc

1292a Blue Hills Avenue
Bloomfield, CT 06002
   (860) 838-2677
Location: Single
Congr. District: 01
County: Hartford

Phase I

Contract Number: W56KGU-20-C-0055
Start Date: 6/19/2020    Completed: 3/28/2021
Phase I year
Phase I Amount
LiquidPiston proposes a 2-5kW heavy-fueled generator based on a novel rotary "X" engine architecture, operating on the High Efficiency Hybrid thermodynamic Cycle (HEHC). In Phase I of the proposed effort, the feasibility of the X-engine based generator will be investigated. A conceptual design will be modeled and assessed against Army requirements, toward a generator configuration to be built in Phase II.

Phase II

Contract Number: W56KGU-20-C-0055
Start Date: 2/16/2022    Completed: 1/26/2023
Phase II year
Phase II Amount
LiquidPiston Inc. (LPI) was awarded a Phase I Army SBIR to assess the feasibility of developing an extremely lightweight and compact 5 kW generator set based on LPI’s novel rotary “XTS” X-Engine platform. The objective of the program was to demonstrate a pathway toward reducing AMMPS generator size and weight by 80%. Over the course of the six-month period of performance spanning from October 2020 to March 2021, LPI successfully developed and validated a concept pathway for integrating the XTS engine core with an appropriate engine “Balance of Plant” (BoP), and specified and sourced state of the art power generation components to support a lightweight 120 VAC 5kW mobile generator. The unit represents a leap forward in genset technology, with a total estimated unit volume of approximately 4.25ft^3, an 85% reduction in size compared to the currently fielded 5kW AMMPS generator ser (MEP-1030). With a predicted dry weight of <110 lbs., an 84% weight reduction over the MEP-1030, the LPI genset can be easily transported by operators in the field, without the need for trailers or heavy equipment required by current 5kW military generator sets. Above and beyond the compact and lightweight nature of the unit, it also pushes the limits of efficiency with an end-to-end electrical conversion efficiency of 92% and a projected brake specific fuel consumption (BSFC) of only 320 g/kWh at rated load. Furthermore, development pathways exist to reduce the BSFC down to 250 g/kwh with targeted improvements to the engine.