Enabling mixing-controlled combustion of low carbon fuels in naval reciprocating engines
Abstract
Approved for Public ReleaseAbstract: Naval engines designed to operate on F76 have high efficiency and desirable performance characteristics (e.g., high low-speed torque) due to the use of a mixing controlled compression ignition (MCCI) combustion process. MCCI requires a fuel with a high cetane number (typically CN>40) to ensure a short ignition delay and stable combustion. Future, low carbon fuels such as methanol and ammonia have cetane numbers below 5, making compression ignition operation challenging. Typical approaches to use these fuels in reciprocating engines have relied on spark-ignited (SI) operation or dual fuel combustion. SI operation results in low efficiency and reduced performance characteristics due to throttling losses and a knock-limited compression ratio. Furthermore, ammonia has a very low flame speed, resulting in challenges operating in an SI mode. Dual fuel combustion, where methanol or ammonia is ignited by diesel fuel, is promising and has the potential for MCCI-like performance characteristics. However, the requirement to carry two fuels on-board complicates battlefield logistics. Accordingly, the proposed program will develop an approach toenable MCCI combustion of methanol and ammonia without the need for a secondary fuel and compare the results to dual fuel operation. It is expected that the understanding developed in the present program would be suitable for a range of future, low carbon fuels. The effort will include a combination of experimental and model/simulation-based development and assessment of approaches to use future low carbon fuels in Naval engines. The outcome of the project will be an assessment of approaches to enable high efficiency combustion of methanol and ammonia for naval applications and evaluation of the net CO2 benefits compared to conventional operation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 11, 2023
- Source ID
- N000142312806
Entities
People
- Sage Kokjohn
Organizations
- Office of Naval Research
- United States Navy
- University of Wisconsin System