Maximum reduction in greenhouse gas emissions by complete replacement of natural gas with pure hydrogen as a sole low reactive fuel in a RCCI engine

Abstract

In order to maximum reduction in hydrocarbon fuels consumption as the largest source of greenhouse gas emissions, the aim of this study is to evaluate a RCCI engine performance fueled with diesel fuel and pure hydrogen as sole low reactive fuel. For this purpose, a single-cylinder heavy-duty diesel engine with bathtub piston bowl profile and compression ratio of 14.88:1 is assessed that operates at its mid-load range from 9.4 to 13.5 bar gross IMEPs. In order to overcome the NOx challenge resulted from using pure hydrogen, the use of suitable amount of EGR and nitrogen addition as air-hydrogen diluents along with the advanced SOI timing were employed. The simulation results show that in a hydrogen-fueled RCCI engine, while reducing the diesel fuel energy share as the only supplier of air-hydrogen mixture ignition energy to about 13%, the HES percentage can be enhanced up to 87%. Although, the SOC will occur with a long delay and the CA50 will take place about 15°CA after the TDC compared to the experimental data, however, the maximum loss of the engine load is less than 6% with the GIE of more than 48% without any exposure to diesel knock. Moreover, not only the EURO VI level of the CO and UHC emissions and the EPA level of Formaldehyde emission can be met, but also, the EURO VI level of NOx emission as the most important challenge of a hydrogen-fueled engine is achievable.

Thermochemical Production of Hydrogen from Biomass: Pyrolysis and Gasification

“…Industrially developed countries visualize achieving the so-called "hydrogen economy", a term coined in 1970 by U.S. scientists John Bockris and Lawrence Walter Jones based on the idea of partially or totally replacing hydrocarbons with hydrogen to significantly reduce greenhouse gases [36]. Technological and economic studies have demonstrated that although hydrogen is a secondary energy vector and is more costly than natural fuels, its use is economically feasible in today's world.…”

A numerical study of piston bowl geometry and diesel injection timing in a heavy-duty diesel/syngas RCCI engine

“…11 However, due to the nature of low temperature combustion and the very lean burning of the air-fuel mixture, presence of significant levels of CO and HC emissions in the exhaust gases are the main disadvantages of applying RCCI combustion mode compared to CDC mode. 12 Meng et al 13 observed that both HC and thermal efficiency can be enhanced by reducing the intake air pressure. One of the critical parameters that determine the total reactivity of the combustion process is the mass ratio of low to high reactivity fuel.…”