• Proceedings of the KSME Conference
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• 2001.06b
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• pp.87-92
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• 2001

In automobile highway tunnels, in order to maintain a suitable environment for drivers and traffic, visibility in the tunnel must be maintained, and the concentrations of poisonous substances including carbon monoxide must be kept at or below allowable levels. For this reason, in long tunnels and tunnels with heavy traffic, ventilation facilities are installed. When the ventilation facilities are run at full capacity, the environment in the tunnel is obviously adequately maintained, but this consumes a great deal of electric power. Consequently, a central problem in highway tunnel ventilation control systems is to keep the pollution concentration at or below the allowable level, and thus provide a safe environment for traffic, while consuming as little electricity as possible. This paper introduces an operation method of longitudinal flow ventilation systems with jet-fan, dust collector and vertical ducts.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.562-572
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• 2015

$NO_x$ emissions from diesel vehicles have been regarded as a main cause of high $NO_2$ concentration in metropolitan area. Recent studies have shown that the on-road $NO_x$ emissions of diesel vehicles are quite higher than the emission limits specified with the pre-defined test method for emission certification. To reduce air pollutants effectively, the discrepancy of emissions in certification and real-driving conditions should be tackled. In this study, the real-driving emissions have been estimated with portable emission measurement system (PEMS). The results of this study have shown that the on-road $NO_x$ emissions from diesel vehicles have been decreased as the introduction of stricter emission regulation, EURO-6, but additional reduction should be still required and robust technologies should be applied to control $NO_x$ in real-driving conditions. RDE-LDV (Real Driving Emission - Light Duty Vehicles) test method being developed in the European Union can represent excessive on-road $NO_x$ emissions of diesel vehicles as applied emission technologies and can be a solution to remove discrepant $NO_x$ emissions between certification and Korean real-driving conditions. Among the $NO_x$ reduction technologies for EURO-6 diesel vehicles, selective catalytic reduction (SCR) system has shown the better performance than lean $NO_x$ trap (LNT) system to control on-road $NO_x$ emissions. Implementing RDE-LDV will require vehicle manufacturers to adopt the more effective $NO_x$ reduction technology in real driving conditions.