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Engine systems
Published in Tom Denton, Automobile Mechanical and Electrical Systems, 2018
Engine oil drawn into the combustion chamber, either from the inlet valve stem or by bypassing the pistons, can also be a source of hydrocarbon pollution. Oil vapours form in the engine crankcase and can escape into the atmosphere. A positive crankcase ventilation system is now used to draw the vapours into the engine so that they are burnt to form water and carbon dioxide.
On aerosol formation by condensation of oil vapor in the crankcase of combustion engines
Published in Aerosol Science and Technology, 2022
N. Nowak, T. Sinn, K. Scheiber, C. Straube, J. Pfeil, J. Meyer, T. Koch, G. Kasper, A. Dittler
Aside from emissions through the tailpipe, which have been studied extensively (e.g., Kittelson 1998; Harris and Maricq 2001; Burtscher 2005; Maricq 2007), combustion engines are known also to emit vapors and aerosols from the crankcase, mostly in the form of oil (Sauter 2004; Agarwal, Goyal, and Srivastava 2011; Johnson 2012; Ehteram et al. 2013). The crankcase ventilation system represents an important source of aerosols. Unless they are treated by adequate means, these oily aerosols contribute significantly to the total emissions to the environment or, in case of engines equipped with a closed crankcase ventilation system (CCV; Figure 1), cause a variety of other problems (Lakshmanan et al. 2019). Currently, the most common approach is to remove such aerosols with an efficient particle separator (Golkarfard et al. 2018). Another, more sustainable approach is to develop in-engine strategies to reduce aerosol production at the source, based on an understanding of aerosol sources and formation mechanisms in that complex crankcase environment.
Gas-phase and semivolatile organic emissions from a modern nonroad diesel engine equipped with advanced aftertreatment
Published in Journal of the Air & Waste Management Association, 2018
Z. Gerald Liu, Wayne A. Eckerle, Nathan A. Ottinger
Three aftertreatment systems were evaluated in this study. The first consisted of a DOC designed to reduce CO, total hydrocarbon (THC), and the soluble organic fraction of PM, as well as convert nitric oxide (NO) to nitrogen dioxide (NO2) for optimal reduction of total NOx, a CuZ-SCR catalyst for NOx emission control, and an AMOX catalyst for ammonia (NH3) reduction. This configuration is referred to as “DOC+SCR” throughout this study. The second configuration consisted of a V-SCR catalyst followed by the same AMOX catalyst as used in the first configuration, referred to as “V-SCR.” The final configuration consisted of the same catalysts as the DOC+SCR configuration, with an additional catalyzed DPF retrofitted upstream of the CuZ-SCR, referred to as “DOC+DPF+SCR.” All catalysts evaluated in this study are state-of-the-art and their sizes are typical of commercial components for this engine, with a maximum SCR gas hourly space velocity in this study of approximately 80,000 hr−1. The engine was equipped with an open crankcase ventilation system, and crankcase emissions were not added to the exhaust.
Emission test on four-stroke single-cylinder S.IENGINE by optimised convergent-type intake manifold
Published in International Journal of Ambient Energy, 2022
K. Raja, M. Amala Justus Selvam
This vacuum can also be used to draw any piston blow-by gases from the engine’s crankcase. This is known as a positive crankcase ventilation system, in which the gases are burned with the fuel/air mixture. The intake manifold has historically been manufactured from aluminium or cast iron, but the use of composite plastic materials is gaining popularity.