Realization of Dual Phase High Temperature Heat Release Combustion of Base Gasoline Blends from Oil Refineries and a Study of HCCI Combustion Processes

Homogeneous Charge Compression Ignition (HCCI) engine has attracted great attention due to its improved performance and emissions compared to conventional engines. It can reduce both Nitrogen Oxides (NOx) and Particulate Matter (PM) emissions simultaneously without sacrificing the engine performance. However, controlling its combustion phasing remains a major challenge due to the absence of direct control mechanism. The start of combustion is entirely initiated by the chemical reactions inside the combustion chamber, resulted from the compression of its homogeneous mixtures. Varying some critical engine parameters can play a significant role to control the combustion phasing of HCCI engine. This paper investigates the characteristics of HCCI combustion fuelled with n-heptane (C7H16) using single-zone model computational software. The model enabled the combustion object to vary from cycle to cycle. Detailed simulations were conducted to evaluate the effects of air fuel ratio (AFR), compression ratio (CR) and intake air temperature on the in-cylinder pressure and heat release rate. The simulation results showed that the single-zone model was able to predict the two-stage kinetic combustion of HCCI engine; the Low Temperature Heat Release (LTHR) and the High Temperature Heat Release (HTHR) regions. It was found that minor changes in AFR, CR and inlet air temperature led to major changes in the HCCI combustion phasing.

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Dual phase high-temperature membranes for CO2 separation – performance assessment in post- and pre-combustion processes

Faraday Discussions ◽

10.1039/c6fd00038j ◽

2016 ◽

Vol 192 ◽

pp. 251-269 ◽

Cited By ~ 7

Author(s):

Rahul Anantharaman ◽

Thijs Peters ◽

Wen Xing ◽

Marie-Laure Fontaine ◽

Rune Bredesen

Keyword(s):

High Temperature ◽

Power Plant ◽

Performance Assessment ◽

Operating Temperature ◽

Co2 Separation ◽

Separation Performance ◽

Dual Phase ◽

Separation Unit ◽

Combustion Processes ◽

Process Evaluations

Dual phase membranes are highly CO2-selective membranes with an operating temperature above 400 °C. The focus of this work is to quantify the potential of dual phase membranes in pre- and post-combustion CO2 capture processes. The process evaluations show that the dual phase membranes integrated with an NGCC power plant for CO2 capture are not competitive with the MEA process for post-combustion capture. However, dual phase membrane concepts outperform the reference Selexol technology for pre-combustion CO2 capture in an IGCC process. The two processes evaluated in this work, post-combustion NGCC and pre-combustion IGCC, represent extremes in CO2 partial pressure fed to the separation unit. Based on the evaluations it is expected that dual phase membranes could be competitive for post-combustion capture from a pulverized coal fired power plant (PCC) and pre-combustion capture from an Integrated Reforming Cycle (IRCC).

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Analysis of Low and High Temperature Heat Release in Dual-Fuel RCCI Engine and its Relationship with Particle Emissions

Journal of Energy Resources Technology ◽

10.1115/1.4053517 ◽

2022 ◽

pp. 1-34

Author(s):

Mohit Raj Saxena ◽

Sahil Rana ◽

Rakesh Kumar Maurya

Keyword(s):

High Temperature ◽

Heat Release ◽

Particle Number ◽

Number Concentration ◽

Particle Emission ◽

Injection Timing ◽

Particle Number Concentration ◽

Particle Emissions ◽

Diesel Injection ◽

Temperature Heat

Abstract This study presents the influence of low-temperature heat release (LTHR) and high-temperature heat release (HTHR) on the combustion and particle number characteristics of the RCCI engine. The study investigates the relationship between the amount of LTHR, HTHR, and particle number emission characteristics. In this study, gasoline and methanol are used as low reactivity fuel (LRF), and diesel is used as a high reactivity fuel (HRF). The LRF is injected into the intake manifold using a port-fuel injection (PFI) strategy, and HRF is directly injected into the cylinder using a direct injection strategy. A particle sizer is used to measure particle emission in size ranging from 5 to 1000 nm. Firstly, the LTHR and HTHR are analyzed for different diesel injection timing (SOI) for RCCI operation. Later, the variation of particle emissions with LTHR and HTHR is characterized. Additionally, empirical correlations are developed to understand the relation between the LTHR and HTHR with particle emission. Two-staged auto-ignition of charge has been observed in RCCI combustion. Results depict that LTHR varies with diesel injection timing and the phasing of HTHR depends on the amount and location of LTHR. Results also showed that HTHR and LTHR significantly influence the formation of particle number concentration in RCCI combustion. The developed empirical correlation depicts a good correlation between diesel SOI and the ratio of HTHR to LTHR to estimate total particle number concentration.

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Optimization of multiple heat releases in pre-mixed diesel engine combustion for high thermal efficiency and low combustion noise by a genetic-based algorithm method

International Journal of Engine Research ◽

10.1177/1468087418767225 ◽

2018 ◽

Vol 20 (5) ◽

pp. 540-554 ◽

Cited By ~ 5

Author(s):

Gen Shibata ◽

Hideyuki Ogawa ◽

Yasumasa Amanuma ◽

Yuki Okamoto

Keyword(s):

High Temperature ◽

Diesel Engine ◽

Heat Release ◽

Noise Reduction ◽

Thermal Efficiency ◽

Fuel Injection ◽

Combustion Noise ◽

Two Stage ◽

Temperature Heat ◽

Optimum Heat

The reduction of diesel combustion noise by multiple fuel injections maintaining high indicated thermal efficiency is an object of the research reported in this article. There are two aspects of multiple fuel injection effects on combustion noise reduction. One is the reduction of the maximum rate of pressure rise in each combustion, and the other is the noise reduction effects by the noise canceling spike combustion. The engine employed in the simulations and experiments is a supercharged, single-cylinder direct-injection diesel engine, with a high pressure common rail fuel injection system. Simulations to calculate the combustion noise and indicated thermal efficiency from the approximated heat release by Wiebe functions were developed. In two-stage high temperature heat release combustion, the combustion noise can be reduced; however, the combustion noise in amplification frequencies must be reduced to achieve further combustion noise reduction, and an additional heat release was added ahead of the two-stage high temperature heat release combustion in Test 1. The simulations of the resulting three-stage high temperature heat release combustion were conducted by changing the heating value of the first heat release. In Test 2 where the optimum heat release shape for low combustion noise and high indicated thermal efficiency was investigated and the role of each of the heat releases in the three-stage high temperature heat release combustion was discussed. In Test 3, a genetic-based algorithm method was introduced to avoid the time-consuming loss and great care in preparing the calculations in Test 2, and the optimum heat release shape and frequency characteristics for combustion noise by the genetic-based algorithm method were speedily calculated. The heat release occurs after the top dead center, and the indicated thermal efficiency and overall combustion noise were 50.5% and 86.4 dBA, respectively. Furthermore, the optimum number of fuel injections and heat release shape of multiple fuel injections to achieve lower combustion noise while maintaining the higher indicated thermal efficiency were calculated in Test 4. The results suggest that the constant pressure combustion after the top dead center by multiple fuel injections is the better way to lower combustion noise; however, the excess fuel injected leads to a lower indicated thermal efficiency because the degree of constant volume becomes deteriorates.

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