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Low-Temperature Combustion Technology on Biodiesel Combustion
Published in Anand Ramanathan, Babu Dharmalingam, Vinoth Thangarasu, Advances in Clean Energy, 2020
Anand Ramanathan, Babu Dharmalingam, Vinoth Thangarasu
Dual-fuel combustion technology using different reactive fuels is called RCCI technology. The combustion phasing is controlled by blending of higher reactive fuel and lower reactive fuel in different proportions (Reitz and Duraisamy 2015). Higher cetane number fuels such as biofuels, diesel, and pyrolysis fuels are used as the pilot fuels. Higher octane number fuels like liquefied petroleum gas (LPG), compressed natural gas (CNG), natural gas, and alcohol fuels are used as the port fuels in the RCCI combustion. During the suction stroke, the low reactive port fuels are injected with air and premixed well due to the cylinder movement. During the compression stroke, the pilot fuels are injected directly into the cylinder after completion of low reactive air-fuel blending. The modification in the blending ratio, appropriate EGR rate, and multiple injections of the pilot fuel are adopted to manage the combustion phasing. Also, these parameters influence NOx and smoke emissions. The early injection of high reactive fuel increases the squish region and promotes NOx emission. Late injection suppresses the NOx emission due to lower peak cylinder temperature (Eichmeier, Reitz, and Rutland 2014).
Biofueled Reactivity Controlled Compression-Ignition Engines
Published in K.A. Subramanian, Biofueled Reciprocating Internal Combustion Engines, 2017
RCCI, which is also called dual-fuel engine combustion technology, is a version of an HCCI-based compression-ignition engine. A compression-ignition engine in RCCI mode operates with two different kinds of fuels as high reactivity fuel for initiating ignition for combusting low reactivity fuel. High-cetane-number fuels, including diesel, biodiesel, F-T, and diesel are high reactivity fuels, whereas higher-octane-number fuels, including methanol, ethanol, natural gas, biogas, and gasoline are as low reactivity fuels. Higher-octane-number fuel, which generally has high volatility and can mix homogeneously with inducting air, is inducted using a low injection pressure system during a suction stroke. High reactivity fuel is injected at the end of a compression stroke using a conventional high injection pressure system, and the fuel first self-ignites (autoignition) due to a low self-ignition temperature and also acts as an ignition source for low reactivity fuels (high self-ignition temperature) that can’t self-ignite.
Compression-Ignition Engine Combustion
Published in Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong, Combustion Engineering, 2022
Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong
Reactivity controlled compression ignition (RCCI) is an extreme version of the PCCI concept: Employing two different fuels with distinct reactivity. The idea is to use a high-reactivity fuel to control the ignition timing and a low-reactivity fuel to determine the combustion duration. The low-reactivity fuel would be premixed, and the high-reactivity fuel would be directly injected into the cylinder (Reitz and Duraisamy 2015).
Evaluation of MWCNT as fuel additive to diesel–biodiesel blend in a direct injection diesel engine
Published in Biofuels, 2023
Hamit Solmaz, Alper Calam, Emre Yılmaz, Fatih Şahin, Seyed Mohammad Safieddin Ardebili, Fatih Aksoy
Homogeneous charge compression ignition (HCCI) and reactivity-controlled compression ignition (RCCI) engines developed as alternative combustion models have lower nitrogen oxide (NOx) and soot emissions than spark ignition (SI) and compression ignition (CI) engines. Thermal efficiency is very high in these combustion modes. However, the operation range of HCCI and RCCI engines is narrow in terms of engine speed and engine load, and there is no physical mechanism controlling the combustion process. The combustion that occurs in HCCI and RCCI combustion modes is dependent on the chemical kinetics of the fuels used [13–16]. Electric vehicle technology is planned to be replaced by internal combustion engines in the automotive industry soon. However, electric vehicles have issues preventing them from being used widely very soon, such as problems with the battery technology, driving range of the vehicle, charging durations, and insufficient charging stations. In addition, when electric vehicles completely replace those with internal combustion engines, how to produce the electricity needed for these vehicles is an additional problem as well [17–20].
Analysis of performance, combustion, and emission parameters in a reactivity-controlled combustion ignition (RCCI) engine – an intensive review
Published in International Journal of Ambient Energy, 2022
P. V. Elumalai, A. R. Pradeepkumar, M. Murugan, A. Saravanan, M. Sreenivasa Reddy, S. Rama Sree, G. Meenakshi Sundaram
Figure 2 demonstrates the RCCI combustion control concept. The term RCCI stands for reactivity controlled compression ignition (RCCI). RCCI technology uses two combustibles, called low-reactivity fuel and high-reactivity fuel. The concept of RCCI mainly focuses on decreasing NOx and particulate matter emissions. Lesser-grade fuel is directly passed into the intake manifold and is thoroughly pre-mixed with air taken through the inlet manifold. The low-reactivity fuels used are biogas, gasoline, compressed natural gas, etc. The mixed charge would be then injected during the intake stroke. Instead, during compression stroke, the high-reactivity fuel will be injected into the charged mixture through an injector (Bendu and Sivalingam 2016). In general, the high-reactivity fuels used in the engine are diesel, biodiesel or a blend of biodiesel and hydrocarbon fuel. The fuel that is injected early will be in the squish zone, whereas the fuel injected next would be the source of ignition. Han et al. (2017) stated that the gradient of reactivity will result in a sequential self-ignition of blended fuel in various positions and uncontrolled ignition. A schematic layout of RCCI technology is shown below. Almost the same layout has been adopted by many researchers who have done their work in the field of RCCI (Liu et al. 2014). A few of them have compared conventional compression ignition and the RCCI engine (Yang et al. 2016).
Large-eddy simulation of split injection strategies in RCCI conditions
Published in Combustion Theory and Modelling, 2022
Bulut Tekgül, Shervin Karimkashi, Ossi Kaario, Heikki Kahila, Éric Lendormy, Jari Hyvönen, Ville Vuorinen
Spray assisted ignition has been investigated extensively in the past in relation to low-temperature combustion (LTC) technologies [1–3]. LTC technologies aim at emission reduction through lower burning temperatures and leaner mixture conditions to mitigate NOx and soot emissions, while targeting performance comparable to Conventional Diesel Combustion (CDC) [3,4]. The most significant LTC strategies are Homogeneous Charge Compression Ignition (HCCI), Premixed Charge Compression Ignition (PCCI) and Reactivity Controlled Compression Ignition (RCCI) [5]. In the present paper, fundamental numerical studies are carried out to gain insights to robust ignition control in RCCI combustion [5]. RCCI combustion aims at mitigating emissions while providing high efficiency through LTC for compression ignition (CI) engines. The working principle of RCCI engines is to create an in-cylinder mixture and reactivity stratification via single or multiple direct injection(s) of a high-reactivity fuel (HRF) (e.g. diesel) into a homogeneous mixture of a low-reactivity fuel (LRF) (e.g. methane) and oxidiser. The difference in the auto-ignition characteristics of the HRF and LRF along with different operational parameters provide control over the ignition timing, as well as the combustion phasing and the duration. The scope of the present work is to provide fundamental insights on the mechanisms that control ignition timing and combustion duration in a dual-fuel multiple injection system through large-eddy simulations (LES).