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Since the introduction of the first Particle Number (PN) regulation for solid particles larger than 23 nm (SPN23) in the European Union (EU), the trend to introduce and strengthen PN regulations has spread globally. PN was added to the regulated components in the European Real Driving Emissions (RDE) regulation in 2017. Furthermore, the scope of the EU regulation will be expanded to include solid particles larger than 10 nm (SPN10) in the future. The authors have previously developed a Portable Emissions Measurement System (PEMS) capable of measuring SPN23. Since measurement of 10 nm PN by PEMS will also be necessary in the future regulations, The authors developed a 10 nm PN-PEMS. In this paper, the technical improvements and the basic performance of the developed 10 nm PN-PEMS are described. The results of SPN10 measurement tests which have been performed on different kinds of vehicles are presented.

This research examined CPC calibration error due to the instability of 10 nm particle. Tandem DMA set-up was used to measure the actual particle size. Emery oil particle shrinks by 0.3 nm after classifier. Residence time in the downstream also affects the shrinkage with its rate 0.18 nm per second. In addition, we confirmed 7 nm particle shrinks more, as anticipated on Kelvin equation. Due to this shrinkage, CPC detection efficiency of 10 nm was reduced by 3% approximately.

The Real Diving Emissions (RDE) regulation has been introduced since September, 2017 by utilizing the Portable Emissions Measurement System (PEMS). For the PEMS for the solid Particle Number (PN) measurement (PN-PEMS), the validation tests are required by comparing to the stationary PN measurement system on a chassis dynamometer prior to the on-road emissions testing. However, there are some cases that the emission results of PN-PEMS have big difference for that of the PMP system as the PN-PEMS does not have the same system configuration and calibration procedures as a PMP system. In this paper, the influence of the calibration procedure to the PN emissions results was observed by applying the calibration procedure of the PN-PEMS to the PMP system. The current systems configurations for PMP system and PN-PEMS, and the differences of them were described. And, the calibration procedure of the PN-PEMS was applied to the PMP system to adjust the system detection efficiency at 23 nm.

The Particle Measurement Programme (PMP) established under the United Nations Economic Commission for Europe has developed the solid particle number (PN) measurement methodology, which has relatively higher sensitivity than the particulate matter measurement protocol. The first PN emission regulation was introduced in 2011. The stationary PN measurement system (PMP system) has been applied in the chassis and the engine test cells. In recent years, real driving emissions (RDE) measurement is attracting attention. Portable emissions measurement systems for PN measurement (PN-PEMS) which can be installed on vehicles during RDE testing are available now. The European RDE regulation requires validation of PN-PEMS by comparing emission measurement results with a stationary PMP system on a chassis dynamometer prior to the on-road emissions testing. Measurement differences between the PN-PEMS and the PMP system has to be within the tolerance defined by the regulation.

Fine particle emissions from engine exhaust have attracted attention because of concern of their higher deposition fraction in alveoli. Since it was observed that sizes of solid particles in exhaust of conventional internal combustion engine technologies are mainly distributed above 30 nm and the mainly irreproducible sensitivity to volatile particles can be reduced, the current solid particle number (PN) measurement methodology was targeted to PN emissions particles larger than 23 nm. The necessity of the measurement of particles smaller than 23 nm is now under discussion. It is also surmised that there is difference between emissions under regulatory defined test cycles and real driving conditions. Currently, implementation of further real driving emission regulations utilizing portable emissions measurement systems (PEMS) is in place for the EU and being actively discussed in other regions.

An on-board solid particle number (PN) analyzer (OBS-ONE-PN) has been developed to measure PN concentrations in engine exhaust under real-driving conditions. Specification of OBS-ONE-PN is based on the recommendation in PEMS-PN draft. OBS-ONE-PN consists of primary diluter, heated transfer tube, heated catalytic stripper (CS), secondary dilutor and particle detector. Volatile fractions which is emitted from the automobile engine are removed by CS, and then only solid particles are counted by a condensation particle counter (CPC). Finally, the system provides results in number concentration. The detailed specifications relating to the OBS-ONE-PN performance such as dilution factor accuracy, volatile particle removal efficiency, overall detection efficiency and durability test results are described in this paper The OBS-ONE-PN is used to characterize PN emission from a gasoline vehicle.

Portable emission measurement systems (PEMS) for particle number (PN) counting are under development in Europe, along with the vehicle testing protocol. A PN PEMS was developed by using a non-heated exhaust diluter, and applying a diffusion charger sensor (DCS) as the PN detector which is fitted with diffusion screens in order to selectively remove all particles, including volatiles, below 30 nm. Detection efficiencies of the DCS could be successfully adjusted by the number of diffusion screens installed before it. Equivalent results of the PN PEMS to a conventional system were observed by vehicle tests. However, variations were observed under specific vehicle operating conditions. Also, as part of the same program, a commercially available hand-held condensation particle counter (CPC) was compared with the standard CPC by vehicle tests as one of candidates to PEMS. Differences in PN concentrations were observed depending on the engine conditions

In order to improve the performance of Engine Management System (EMS), it becomes more important to accurately detect the position of cam and crank with rotation sensors, usually as referred cam and crank sensor. In addition, expectations for the idle stop system to follow the reinforcement of emission regulations require cam and crank sensors to implement the function of reverse rotation detection. This paper discusses our development of a new generation rotation sensor (MR3) that uses AMR (Anisotropic Magneto Resistance) for accurate rotation detection to meet all system and market demands with minimum number of components to achieve high quality but less expensive price.