Numerical Simulation of the Effects of Charge Stratification on Combustion and Emissions

Zheng, Zhimin; Yao, Mingfa

doi:10.1021/ef070071k

Cited by 5 publications

(4 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both experimental and numerical studies have been conducted to explore the charge stratification to control the HCCI combustion by port injection and DI of the same n-heptane fuel Zheng and Yao, 2007). The stratification can be altered by changing the ratio between the port and DI fuel mass and also the DI timing.…”

Section: Charge Reactivity and Stratification Controlled Combustion Smentioning

confidence: 99%

Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

et al. 2015

Self Cite

View full text Add to dashboard Cite

(2015) Combustion mode design with high efficiency and low emissions controlled by mixtures stratification and fuel reactivity. Front. Mech. Eng. 1:8. doi: 10.3389/fmech.2015.00008 Combustion mode design with high efficiency and low emissions controlled by mixtures stratification and fuel reactivity This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors' group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI) combustion, stratification controlled premixed charge compression ignition combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fueled with both high cetane number fuels, such as dimethyl ether and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline, and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition/highly premixed charge combustion mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

show abstract

Section: Charge Reactivity and Stratification Controlled Combustion Smentioning

confidence: 99%

Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Unfortunately, the coupling process incurs a high computational cost, rendering this method unattractive to researchers. As an alternative, many researchers have adopted reduced chemical kinetics coupled with CFD. − Noel et al used reduced chemical kinetics of n -heptane with multidimensional CFD code to simulate HCCI combustion in diesel engines. Their study shows that the reduced mechanism behaves similarly to the detailed models for the description of the two-stage phenomenon and also for the temperature and pressure inside the cylinder.…”

Section: Introductionmentioning

confidence: 99%

“…Kim and Lee used KIVA-3V/reduced chemical kinetics to study the effects of injection strategy on the combustion process and the chemical reaction path in an HSDI diesel engine. Zheng and Yao adopted a fully coupled multidimensional CFD and reduced chemical kinetics model to investigate the effects of charge stratification on HCCI combustion and emissions. Mo et al used a DME reduced chemical kinetics model coupled with CFD to predict combustion and emissions of DME HCCI.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Methanol/Dimethyl Ether Dual-Fuel Compound Combustion

Chen¹,

Yao²,

Zheng³

et al. 2009

Energy Fuels

Self Cite

View full text Add to dashboard Cite

This paper experimentally and numerically investigates the effects of injection timing on combustion of a methanol/dimethyl ether (DME) dual-fuel compound at various methanol concentrations. In this dual-fuel compound combustion approach, methanol is directly injected into the cylinder, and DME is injected at the intake port. The experimental results indicate that methanol injection timing has an obvious effect on the heat release process of the dual-fuel compound combustion, and the effect of methanol concentration (i.e., the engine load) on injection timing is also evident. Late injection should be adopted to achieve smooth combustion and low NO x emissions at high methanol concentrations. Moderate injection timing should be adopted to achieve higher indicated thermal efficiency (ITE) at low methanol concentrations. The simulation results, using computational fluid dynamics (CFD) combined with reduced chemical kinetics, show that methanol injected at -26 °CA after top dead center (ATDC) has a remarkable effect on the high-temperature reaction of DME. In the case of injection timing at -26 °CA ATDC, the high-temperature combustion region is concentrated within the combustion chamber, which results in a higher NO concentration. With injection timing at -6 °CA ATDC, by contrast, the high-temperature combustion region is dispersed in the compression clearance and near the chamber wall, which leads to a relatively low NO concentration. Increasing injection pressure is an effective way to shorten the duration of the methanol/DME dual-fuel compound combustion achieved by later injection.

show abstract

“…A little inhomogeneity in fuel concentration and temperature in mixing can produce significant effects on autoignition and combustion processes. Utilizing the inhomogeneity (charge stratification) is an important path to achieve clean and high-efficiency combustion in engines. − It can be concluded that stratification combustion has the potential to extend the high-load limits for HCCI operation and reducing UHC and CO emissions.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Oxygen Concentration Effects on Combustion Process and Emissions of Diesel Engine

Zheng¹,

Yao²

2009

Energy Fuels

Self Cite

View full text Add to dashboard Cite

The mechanism of oxygen concentration effects on the combustion process of diesel combustion and the effects of injection pressure and intake pressure on low-temperature combustion are investigated by CFD simulation. The oxygen concentration is modulated by CO 2 . The results indicate: with the decrease of oxygen concentration, the peak of the average in-cylinder pressure decreases and the ignition delay becomes long. Decreasing oxygen concentration is the most effective method to control NO x emissions. With the decrease of oxygen concentration, soot emissions increase first and then decrease. It is the essential reason of low soot emissions at low oxygen concentrations that the low in-cylinder combustion temperature leads to the inhibition of soot formation. With the increase of injection pressure, the flow velocity and turbulent kinetic energy in the cylinder increase, which are beneficial to improving the mixing of fuel and air; soot emissions decrease; and NO x emissions increase. The enhancement of intake pressure improves the condition of oxygen lack at lower oxygen concentration. With the increase of intake pressure, ignition delay becomes long. Soot and NO x emissions decrease.

show abstract

Numerical Simulation of the Effects of Charge Stratification on Combustion and Emissions

Cited by 5 publications

References 30 publications

Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

Experimental and Numerical Study of Methanol/Dimethyl Ether Dual-Fuel Compound Combustion

Mechanism of Oxygen Concentration Effects on Combustion Process and Emissions of Diesel Engine

Contact Info

Product

Resources

About