Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal combustion engines

The review paper summarizes major developments in vehicular emissions regulations and technologies in 2013. First, the paper covers the key regulatory developments in the field, including proposed light-duty (LD) criteria pollutant tightening in the US; and in Europe, the continuing developments towards real-world driving emissions (RDE) standards. Significant shifts are occurring in China and India in addressing their severe air quality problems. The paper then gives a brief, high-level overview of key developments in fuels. Projections are that we are in the early stages of oil supply stability, which could stabilize fuel prices. LD and HD (heavy-duty) engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging NOx and GHG regulations. HD engines are or will soon be demonstrating 50% brake thermal efficiency using common approaches. NOx control technologies are then summarized, including SCR (selective catalytic reduction) systems and SCR filter developments. Emphasis is on low-temperature deNOx and integration of components and control. Diesel PM (particulate matter) reduction technologies are evolving around the behavior of ash deposits and SCR integration. Filters for direct injection gasoline applications are developing very rapidly, and in some cases the back pressure, light-off characteristics, and emissions reductions are very similar to standard three way catalysts (TWCs). Oxidation catalysts mainly involve developments towards stubborn problems, like low-temperature performance with exhaust with high hydrocarbon and CO, and methane oxidation. Finally, the paper discusses some key developments in gasoline gaseous emission control, focusing on matching engine calibration with emissions system characteristics; and on lean burn gasoline emissions control. CITATION: Johnson, T., "Vehicular Emissions in Review," SAE Int. J. Engines 7(3):2014, doi:10.4271/2014-01-1491. 2014-01-1491 Published 04/01/2014 Copyright © 2014 SAE International doi:10.4271/2014-01-1491 saeeng.saejournals.org 1207 This paper is posted on this website with permission from SAE International. It may not be shared, downloaded, duplicated, or transmitted in any manner without prior written permission from SAE.

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Vehicular Emissions in Review

Evolution, challenges and path forward for low temperature combustion engines

RCCI (reactivity controlled compression ignition) engines are found to be capable of achieving higher thermal efficiency and ultra-low NOx and PM emissions. The reactivity controlled combustion is accomplished by creating reactivity stratification in the cylinder with the use of two fuels characterized by distinctly different cetane numbers. The low reactivity (i.e., low cetane number) fuel is firstly premixed with air and then charged into the cylinder through the intake manifold; later, the high reactivity (i.e., high cetane number) fuel is injected into the charged mixture through a direct injector. Subsequently, the reactivity stratification is formed. By strategically adjusting the ratio of two fuels and injection timings, the produced reactivity gradient is able to control the combustion phasing and mitigate the pressure rise rate, as well as the heat release rate. Alternatively, structural factors such as CR (compression ratio) and piston bowl geometries can also affect the combustion characteristics of RCCI. Besides the engine management, the fuels that could be utilized in RCCI engines are also crucial to determine the evaporation, mixing, and combustion processes. To gain a comprehensive knowledge on the state-of-the-art of RCCI combustion, detailed review on the management of RCCI engines has been presented in this paper. This review covers the up-to-date research progress of RCCI including the use of alternative fuels and cetane number improvers, and the effects of fuel ratio, different injection strategies, EGR rate, CR and bowl geometry on engine performance and emissions formation. Moreover, the controllability issues are addressed in this article.

Review on the management of RCCI engines

Low-temperature combustion is an emerging engine technology that has the ability to yield low NOx and soot emissions while maintaining high fuel efficiency. Low-temperature combustion strategies in...

Dan DelVescovo

Papers

RCCI Engine Operation Towards 60% Thermal Efficiency

Natural Gas for High Load Dual-Fuel Reactivity Controlled Compression Ignition in Heavy-Duty Engines

Numerical Study of RCCI and HCCI Combustion Processes Using Gasoline, Diesel, iso -Butanol and DTBP Cetane Improver

Isobutanol as Both Low Reactivity and High Reactivity Fuels with Addition of Di-Tert Butyl Peroxide (DTBP) in RCCI Combustion

The Effects of Charge Preparation, Fuel Stratification, and Premixed Fuel Chemistry on Reactivity Controlled Compression Ignition (RCCI) Combustion