Development of a Direct-Injected Natural Gas Engine System for Heavy-Duty Vehicles: Final Report Phase II

This report summarizes the results of Phase 2 of this contract. We completed four tasks under this phase of the subcontract. (1) We developed a computational fluid dynamics (CFD) model of a 3500 direct injected natural gas (DING) engine gas injection/combustion system and used it to identify DING ignition/combustion system improvements. The results were a 20% improvement in efficiency compared toPhase 1 testing. (2) We designed and procured the components for a 3126 DING engine (300 hp) and finished assembling it. During preliminary testing, the engine ran successfully at low loads for approximately 2 hours before injector tip and check failures terminated the test. The problems are solvable; however, this phase of the program was terminated. (3) We developed a Decision & Risk Analysismodel to compare DING engine technology with various other engine technologies in a number of commercial applications. The model shows the most likely commercial applications for DING technology and can also be used to identify the sensitivity of variables that impact commercial viability. (4) MVE, Inc., completed a preliminary design concept study that examines the major design issues involvedin making a reliable and durable 3000 psi LNG pump. A primary concern is the life of pump seals and piston rings.; ; Plans for the next phase of this program (Phase 3) have been put on indefinite hold. Caterpillar has decided not to fund further DING work at this time due to limited current market potential for the DING engine. However, based on results from this program, we believe that DInatural gas technology is viable for allowing a natural gas-fueled engine to achieve diesel power density and thermal efficiency for both the near and long terms.