Gas-phase and semivolatile organic emissions from a modern nonroad diesel engine equipped with advanced aftertreatment

Abstract

U.S. Tier 4 Final and Euro Stage IV and V regulations for nonroad compression-ignition engines have led to the development of exhaust aftertreatment technologies optimized for nonroad engines and duty cycles. In this study, several aftertreatment configurations consisting of state-of-the-art diesel oxidation catalysts (DOCs), diesel particulate filters (DPFs), copper (Cu) zeolite- and vanadium-based selective catalytic reduction (SCR) catalysts, and ammonia oxidation (AMOX) catalysts are evaluated using both nonroad transient (NRTC) and steady (8-mode NRSC) cycles in order to understand both component- and system-level effects of diesel aftertreatment on gas-phase, semivolatile, and particle-phase and particle-bound unregulated organic emissions. Organic emissions reported in this work include total hydrocarbon (THC), n-alkanes, branched alkanes, saturated cycloalkanes, aromatics, aldehydes, ketones, hopanes, steranes, and soluble organic fraction (SOF). Brake-specific emissions are reported for four configurations, including engine-out, DOC+CuZ-SCR+AMOX, V-SCR+AMOX, and DOC+DPF+CuZ-SCR+AMOX, and conversion of engine-out emissions is reported for the three aftertreatment configurations. Mechanisms responsible for the reduction of organic species are discussed in detail. This summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere with tools such as the U.S. Environmental Protection Agency's Motor Vehicle Emissions Simulator (MOVES2014a) model. Implications: Anthropogenic emissions are a source of significant human health and environmental risk. This study, focused on the treatment of exhaust emissions from a modern nonroad diesel engine with a variety of aftertreatment configurations, examines the impact that human industrial activity can have on air pollution. In particular, we focus on the remediation of gas-phase and semivolatile organic emissions by emission reduction technologies. This detailed summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere with tools such as the U.S. Environmental Protection Agency's MOVES2014a model.

Lung function and self-rated symptoms in healthy volunteers after exposure to hydrotreated vegetable oil (HVO) exhaust with and without particles

“…Exhaust aftertreatment systems are used in diesel vehicles in order to reduce the environmental and health hazardous emissions of PM (both mass and number concentration), CO, NO x , and organic compounds such as PAHs. An aftertreatment system can, for example, contain a diesel oxidation catalyst (DOC) that oxidizes CO and organic compounds [ 39 , 40 ], and a diesel particle filter (DPF) that oxidizes soot particles which removes significant amounts of PM [ 41 ]. Hence use of aftertreatment systems should reduce exposure to such emissions and their associated health effects.…”

Size-resolved physico-chemical characterization of diesel exhaust particles and efficiency of exhaust aftertreatment

“…The reduction percentage of total particle phase I+SVOC over the DOC was more than 74% and over the DOC+DPF was approximately 91%. The DOC can help oxidise the engine-out gas phase SVOC (Liu et al, 2018) and consequently decrease the particle phase I+SVOC collected in the diluted exhaust. Later, when the exhaust gas passes the catalysed DPF, apart from further conversion of I+SVOC, particles are physically trapped.…”

“…Some studies have shown that I+SVOC emission factors are strongly influenced by the exhaust aftertreatment technology installed on the vehicle (Gordon et al, 2014;Zhao et al, 2015;Liu et al, 2018;May et al, 2013). Liu et al (2018) reported that the soluble organic fraction of particle emissions from a large (8.9 L) non-road diesel engine was decreased by >80% when using a diesel oxidation catalyst (DOC) in combination with a selective catalytic reduction system (SCR) and a DPF. They suggested that a large fraction of SVOC is possibly in the gas phase under exhaust conditions and is influenced by the DOC.…”

Fresh and Aged Organic Aerosol Emissions from Renewable Diesel-Like Fuels HVO and RME in a Heavy-Duty Compression Ignition Engine

“…Switching to these renewable and sustainable fuels has shown the potential to reduce GHG emissions [58] and improve the air quality with the existing fleets of vehicles, especially of those without an exhaust aftertreatment system (EATS) [21]. EATSs are designed to reduce multiple pollutants found in diesel exhaust [59]. The main function of a diesel oxidation catalyst (DOC) is to ensure the sufficient oxidation of the gas phase HC and CO, but also to remove the condensable organic fraction while still in the gas phase [60] [61].…”