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The regulated level of particulate mass for 2007 heavy duty diesel on-road engines is 0.01 g/bkhp-hr. Measurement of this low level of particulate by weighing is costly and time consuming. The weighing method must measure 100 μg or less of particulate on a filter that weighs about 100 mg with a resolution of ± 2.5 μg or better. This means that the microbalance and sampling handling procedure must be accurate within ±25 ppm by mass or ±1/40,000. It requires a microbalance with 0.1 μg precision housed in a special environment. Moreover, the weighing method involves a lengthy process. The filter must be equilibrated, and then pre- and post-weighed, usually with repeat measurements. An alternative to gravimetric analysis is a thermal mass analyzer that measures the semi-volatile organic fraction (SOF), as well as soot and sulfate fractions of the particulate matter (PM) collected on a cleaned quartz filter. The calibration of the thermal mass measurement is discussed in detail.

In order to control diesel engine emission, several after-treatment technologies have been studied and developed to reduce particulate matter (PM) and nitrogen oxides. Such reduction is making it hard to measure the mass of such pollutants. In the present study, a new method to analyze nitrogen compounds in vehicle particulate has been described. The method is based on the technique for separate analysis of SOF, soot and sulfates in particulate, which has been previously reported by the authors. The new method utilizes oxidation process in a furnace at high temperature and a chemiluminescence detector (CLD) to measure generated NO and NO2. In this paper, principle and concept of the method has been described. In addition, feasibility of the method for analyzing nitrogen compounds in vehicle PM has been discussed, with practical experiments using modeled samples and actual particulate.

In order to develop the engines that emit only small amount of Particulate Matter (PM), there are various demands for measurement techniques for PM, such as real-time measurement, low-mass measurement, and analysis in short time. This paper reviews two kinds of instruments that have been newly introduced for PM measurement. One is the real-time PM analyzer applying two Flame Ionization Detectors (FID). This method utilizes an area accumulation technique for spike-shaped signals that are observed when soot particles are fed into a FID detector. And Soluble Organic Fraction (SOF) can be calculated continuously from difference of signals of two detectors. Another is the low-mass PM analyzer based on process of vaporization, oxidization and deoxidization. The performances of these two measurement techniques are described in this paper, using model samples and actual particulate.

For the purposes of environmental protection, regulations of particulate matter are becoming more stringent year by year. Accordingly, engine systems have been improved and particulate emissions are much lower compared to those of previous engine systems. The automotive industry generally uses a gravimetric method to quantify particulate emissions. It is becoming increasingly difficult to quantify particulate emissions using a conventional gravimetric balance because the amount of particulates continues to decline. In order to overcome this problem, a new method has been developed that uses gas analyzers to measure potentially as much as several micrograms of particulates. Furthermore, with this method, it is possible to simultaneously analyze volatile organic fraction (VOF), soot, and sulfates. The particles collected by a quartz filter are placed in a furnace at a specific temperature, and VOF and sulfates are vaporized in an inert atmosphere.

Particulate matter (PM) emission from vehicles is one of the biggest issues in terms of environmental protection and influence to human body. Thus, a variety of measurement technologies have been develop so far. Currently, a gravimetric method is most commonly used in the automotive industry, partially because it is specified in the regulations. This method uses a combination of a dilution tunnel and a filter that collects the PM from the diluted sample gas with subsequent weighting by a micro balance. However, since this technique is a batch measurement, it is impossible to determine at what point of the emissions test the Soot, SOF (Soluble Organic Fraction), and the total PM are emitted. Thus the demand for real-time PM measurement under transient test conditions has increased.

The environmental effects of particulate matter (PM) emissions from vehicles are an increasing concern to those concerned with air quality. A variety of technologies have been developed to measure exhaust particulates. The automotive industry generally uses the gravimetric method to quantify particulate emissions. This method uses a combination of a dilution tunnel and filter to collect PM from the diluted sample gas. The collected PM is later weighed on a microbalance. Because this technique is a batch measurement, it is not possible to determine at what point of an emissions test drive cycle the soot, soluble organic fraction (SOF) and total PM are emitted. A more accurate characterization of PM emissions will require real-time PM measurement under transient test conditions.