Effects of H2 and CO enrichment on the combustion, emission and performance characteristics of spark ignition natural gas engine

Abstract

h i g h l i g h t sCO is less effective than H 2 in improving engine combustion and thermal efficiency. Both CO and H 2 smoothes engine operation and lowers THC emission. CO is less effective in improving the laminar flame speed of CH 4 than H 2 . a b s t r a c tFuel reforming is an attractive way for improving the performances of internal combustion engine. The primary components of the reformed gas are H 2 , CO, CO 2 and N 2 . A detailed knowledge of each component in reformed gas is essential for judging or making better use of the reformed gas as well as reforming technologies. In this paper, the influences of the major combustibles of the reformed gas, H 2 and CO, on the performances of a lean burn spark ignition natural gas engine are investigated. Results indicate that addition of H 2 and CO could improve in-cylinder combustion, smooth engine operation and increase engine thermal efficiency. With the addition of H 2 and CO, both the peaks of in-cylinder pressure and heat release rate increase, flame development duration and rapid combustion duration as well as CovIMEP decrease. However, CO is less effective compared with H 2 . The influence of H 2 on engine THC emission is insignificant while addition of CO tends to increase engine CO emission remarkably owing to the quenching and crevice effect. Both H 2 and CO tend to worsen engine NO x emission due to the increased in-cylinder temperature while the effect of H 2 is more distinct. The simulation of laminar flame speed manifests that addition of H 2 and CO increase O, H and OH radical concentration and hence improve the flame propagation and the combustion process, resulting in improved laminar flame speed of the fuel-air mixtures. In compare, H 2 addition leads to higher laminar flame speed than CO addition does. The whole investigation of this paper implies that both H 2 and CO in the reformed gas are effective in improving engine combustion and effective thermal efficiency while H 2 is more effective.

Potential of fueling spark-ignition engines with syngas or syngas blends for power generation in rural electrification: A short review and S.W.O.T. analysis

“…The results of Cha et al [34] are in agreement with those found by He et al [23]. The latter studied the effects of enriching natural gas, composed of 96% methane, with H 2 , CO, or a mixture of the two.…”

“…The behaviors of pollutant emissions in each article reviewed are summarized in Table 2. The main factor determining the quantity of CO in the exhaust is its presence in the input syngas [23,24,25]. More CO is transferred to the exhaust for lower combustion efficiency which is affected by the air-fuel ratio and engine speed [24].…”

A Numerical Study of the Effects of Using Reformer Gas on Ignition Characteristics under Dual-Fuel Engine-Relevant Conditions

“…In addition, H 2 is a kind of carbon-free fuel, and it can reduce the carbon emission of compression ignition engines. H 2 and reformer gas (syngas includes H 2 and CO) have been considered as suitable blended fuels for internal combustion engine applications [17]. At present, many scholars are studying the preparation and combustion of syngas in internal combustion engines [18].…”

Kinetic and CFD Modeling of Exhaust Gas Reforming of Natural Gas in a Catalytic Fixed‐Bed Reactor for Spark Ignition Engines

“…It was found that a small amount of hydrogen can improve performance and reduce exhaust gas emissions. Adding hydrogen to natural gas increases the cylinder pressure and temperature of natural gas engine owing to the improved heat release rate, which contributes to shortening the combustion duration and achieving higher engine stability . Despite all the advantages of hydrogen addition for natural gas engine performance, it still faces many challenges for use in ICEs.…”