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An analyzer for real-time measure of sulfur compounds in vehicle exhaust gas has been developed utilizing the Ultra Violet Fluorescence (UVF) detection technology. This analyzer measures Total Sulfur (TS) including sulfates in PM. For detecting sulfur components as TS, sample gas is introduced into two combustion furnaces. The TS measurement by the UVF analyzer is considered to be applicable to real-time oil consumption test with sulfur tracing method, because it has high sensitivity and quick response. In this study, the UVF method is evaluated in detail based on the vehicle emission test results.

A new hydrogen analyzer using a magnetic sector mass spectrometer (MS) has been developed to perform continuous analysis of hydrogen gas concentrations in exhaust gas. This method is insensitive to substances other than hydrogen gas ions and so is not easily affected by the presence of other molecules. In addition, this analyzer has a fast response compared to conventional hydrogen analyzers, which employ other measurement principles. The T90 response time is about 1 second. The minimum sensitivity is few tens of ppm. Because of these characteristics, the sector MS method has significant potential for analyzing hydrogen concentrations in exhaust gas continuously. In this study, the authors performed continuous emissions measurement of several kinds of gasoline engine vehicle in a chassis test cell using the hydrogen gas analyzer in combination with other gas analyzers.

Nitrous oxide (N₂O) emission reduction has gained large prominence recently due to its contribution to the climate change as a greenhouse gas. The United States Environment Protection Agency (US-EPA) together with the United States Department of Transport (DOT) has already regulated the N₂O emissions from light-duty vehicles (LDV) to 0.010 g/mile. For LDV, N₂O measurement should be done from sample storage bags over the light-duty FTP drive cycles. N₂O emission standard of 0.10 g/bhp-hr for heavy-duty engines (HDE) is also finalized. The final N₂O standard becomes effective in 2014 model year for diesel engines. Usually raw or diluted exhaust is measured for HDE emission testing. Therefore, an analyzer capable of measuring N₂O from bag and from diluted sample continuously is required to support both LDV and HDE regulations.

In the engine and vehicle test procedures described in Parts 1065/1066 of Title 40 of the Code of Federal Regulations (CFR), the United States Environmental Protection Agency (US-EPA) allows for the measurement of N2O emissions from sample storage bags, from a continuous dilute stream or a raw exhaust stream. Typically, batch (Bag) sampling has better accuracy and repeatability, but continuous sampling is more efficient in terms of test cell running time and provides test-mode emissions with good correlation to bag measurements. In this study, correlations between bag sampling and continuous dilute exhaust sampling were investigated using a fleet of vehicles with a wide range of N2O emission levels. Very good correlation between these two sampling methods was observed for the majority of tests conducted. In the best cases, differences in average N2O concentration levels measured by these two methods were less than +/− 1%.