AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Results of On-line Measurement of Volatile Organic Compounds Adsorbed on Diesel Exhaust Particles by PTR-TOFMS
NOBUHIRO YANAGISAWA, Kenji Enya, ISUZU Advanced Engineering Center, Ltd.
Abstract Number: 672 Working Group: Instrumentation and Methods
Abstract Emissions from modern diesel engines for automobiles have become very low by progress in combustion technology and adoption of emission aftertreatment devices. Diesel emissions consist of a large number of compounds in gas- and particle-phase. PTR-TOFMS (Proton Transfer Reaction – Time of Flight Mass Spectrometer) is able to analyze gaseous organic compounds (i.e. volatile organic compounds) on-line in real time with high sensitivity. To analyze particle-phase organic compounds by PTR-TOFMS, sampled exhaust was passed through a heating tube to evaporate particle-phase compounds, which were then introduced to PTR-TOFMS. To determine the concentrations of particle-phase compounds, 2 experiments were conducted. At the first experiment, the heating tube was kept at lower temperature (ca. 100 degC) to measure the concentrations of gas-phase organic compounds. At the second experiment, the heating tube was heated at higher temperature (ca. 300 degC) to measure the total concentrations of gas- and particle-phase organic compounds. The concentrations of particle-phase compounds were determined from the difference between the two measured values.
In this work, analysis of particle-phase organic compounds by PTR-TOFMS was conducted using a modern HD diesel engine (displacement 3L with turbo-intercooler) for small trucks. Exhaust was sampled from an exhaust pipe to a partial flow dilution system. In the dilution system the sampled exhaust was mixed with dilution air at a constant dilution ratio. The diluted exhaust was measured by PTR-TOFMS for organic compounds analysis and EEPS (Engine Exhaust Particle Sizer) for particle sizing.
This paper shows results of emissions of particle-phase organic compounds and particle size distributions during a ramped steady state operation of the engine. The results showed that particle-phase compounds include higher m/Z compounds and particle size distribution is also discussed.