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Horiba on-board diesel exhaust particulate sampler (OBS-PM) is a filter based partial flow particulate sampling system used for On-board diesel particulate matter (PM) measurement. It takes sample from either raw or diluted exhaust. It can run at constant dilution ratios or at variable dilution ratios with proportional control on the sample flow. The diluted exhaust moves through a pre-weighed 47 mm particulate filter and PM is collected on the filter. By weighing the loaded sample filter, PM emission from the engine or the vehicle can be determined. The performance of the OBS-PM meets most of requirements for a real-time partial flow sample system (PFSS) recommended by ISO 16183 [2]. The physical size and the power consumption of the instrument are minimized. It is powered with four 12 volts batteries, and can be installed on a vehicle for real-world PM emission evaluation.

The prototype solid particle counting system (SPCS) has been used to study solid particle emission from gasoline and diesel vehicles. As recommended by the PMP draft proposal, exhaust is diluted by a Constant Volume Sampler (CVS). The SPCS takes the sample from the CVS tunnel. Transient test cycles such as EPA FTP 75, EPA HWFET (EPA Highway Fuel Economy Cycle), and NEDC (New European Driving Cycle) were tested. The repeatability of the instrument was evaluated on the diesel vehicle for three continuous days. The instrument exhibits good repeatability. The differences for the EPA ftp 75, the EPA HWFET, and the NEDC in three continuous tests are ± 3.5%. The instrument is very sensitive as well and detects the driving differences. A large number of solid particles are found during the hard acceleration from both the gasoline and the diesel vehicles. Solid particle emissions decrease quickly at deceleration and when vehicles approach constant speed.

An on-board diesel particulate measurement (OBS-TRPM) instrument is developed to measure on-road exhaust PM emission at Horiba. It is used to characterize particulate matter (PM) emission from a gasoline vehicle, the 1999 Ford Windstar with California Ultra Low Emission (ULEV) certification. PM emissions from three test cycles, EPA FTP 72, SFTP-US06, and new European drive cycle (NEDC), are evaluated. It is found that the PM emission from the SFTP-US06 with the cold start is roughly two times higher than PM emissions from the cold FTP 72 and the cold NEDC. This may be due to aggressive drive patterns for the US06 while the vehicle is still cold. The aggressive drive pattern for the US06 makes the gasoline vehicle emit a much higher fraction of elemental carbon (EC), and lower fraction of organic carbon (OC). Fractions of the EC from the vehicle are 9.1% for the FTP 72, 6.3% for the NEDC, and 56.6% for the US06.