Particle number and size distribution characteristics from diesel- and liquefied-natural-gas-fuelled buses for various emission certification modes in the Republic of Korea

Abstract

This study was primarily focused on the experimental comparison of the particle emission characteristics of diesel and liquefied-natural-gas (LNG) fuels for heavy-duty vehicles. Particulate matter from various heavy-duty engines and vehicles were analysed with a golden particle measurement system recommended by the Particle Measurement Program. This system consists of a constant-volume sampler, a particle number counter, and particle number diluters. To verify the particle number and size distribution characteristics of diesel-fuelled engines and buses, including LNG fuel, various dynamic operation modes, such as the European Transient Cycle (ETC) mode, the European Stabilized Cycle (ESC) mode, and the National Institute of Environmental Research mode, uniquely developed in Korea, were evaluated. The formation of the particles depended closely upon the vehicle speed and the load conditions of each mode. In particular, the particle number sharply increased for fast-transient-acceleration and high-load operation within a heavy-duty engine. The partial diesel particulate filter efficiency was evaluated under the ETC and ESC modes using both engine and vehicle dynamometers.