A Study on the Mechanism of Transient Reaction and Purification Performance Improvement of Three-way Catalysts with High Frequency Perturbation

Masato Terasawa･Yuta Sugaya･Koki Umemoto･Jin Kusaka (Waseda University)

A 2.5L gasoline engine was used to investigate the amplitude and frequency effects of perturbations caused by fast switching of air/fuel ratios on purification characteristics. Pd/Al was used as the test catalyst. The results showed that the purification rates of NO, CO, and THC were improved by increasing frequency and decreasing amplitude, with NO and CO having higher sensitivity to frequency.

Gasoline Particulate Filter for Tier4 Regulation

Ryuta Takai･Takashi Aoki･Tasuku Matsumoto･Yuji Sasaki･Kiwamu Sugiura･Yuichi Hamazaki･Masaki Ito (NGK Insulators)

Tier 4 regulations in the United States tighten the PM (Particle Mass) regulation value to 0.5 mg/mile. Only improving engine control is not enough to meet Tier 4 regulations, and it is expected that gasoline-powered vehicles in the United States will be required to be equipped with GPF. In order to consider a suitable GPF for Tier 4 regulations, NGK has evaluated the filtration performance of GPFs under conditions including the newly regulated cold conditions. This paper presents the evaluation results and suitable GPF for Tier 4.

Leveraging DOConFilter to Improve Exhaust System Packaging

Shiori Shiraki･Takashi Kinoshita･Yohei Mitsui･Tsuyoshi Asako･Katsunori Tanaka･Tasuku Matsumoto･Takashi Aoki (NGK Insulators)

Tightening of PM/PN and NOx emission regulations worldwide increase complexity of aftertreatment system. Due to limited space, DOConFilter, which bundles DOC function into DPF, attracts attention from Off-highway OEMs as a downsizing solution. DOConFilter can effectively replace DOC + catalyzed DPF or DOC + uncatalyzed DPF systems. On the other hand, downsides of DOConDPF are increase of pressure drop and mediocre regeneration efficiency due to combined washcoat on DPF.
This presentation reports the development of DOConFilter, which aims to improve pressure drop and regeneration efficiency by combination of high filtration material and high cell density.

Development of a Method for Measuring CO₂ Concentration in Amine-based Solvents using Fluorescent Dyes

Shohei Tomita･Michihiko Yamamoto･Masaki Nishikawa (Aisin)･Yasuhiro Egami･Yui Kiyota (Aichi Institute of Technology)

Efforts are underway in the automotive industry to develop devices for capturing and recovering CO2 emissions from factories in order to achieve carbon neutrality. In this report, we introduce a technology that has been established to visualize the CO2 concentration distribution in a solution using an optical method with fluorescent dyes in a system that separates and recovers CO2 from exhaust gases using the amine scrubbing method.

Consideration on Understanding the NOx Purification Performance of Urea SCR Catalyst Installed in Heavy-duty Vehicles during the Use Process

Toshiro Yamamoto (NALTEC)

Data on the NOx purification performance of copper-based zeolite SCR catalysts installed in vehicles that comply with the 2016 exhaust gas regulations was collected continuously by conducting chassis dynamometer tests and actual road driving tests as the accumulated mileage increased. Using these, the NOx purification rate, space velocity, etc. were used as analytical indices to consider the NOx purification performance of the urea SCR catalyst during the use process. As a result, when the NOx purification performance of the urea SCR catalyst decreases during use, it was found that the NOx purification rate decreased significantly as the space velocity increases.

A State-of-the-art Soot Filtration Model of a Particulate Filter: Application to an Estimation of a Particle Emission Downstream of the Filter

Kazuki Nakamura (Waseda University)･Anton Nahtigal (AVL-AST d.o.o. Slovenia)･Kyohei Yamaguchi (Kokushikan University)･Jin Kusaka (Waseda University)

The Euro 7 emission standard further tightens a particle emission. It requires developments of emission control systems and simulations with improved accuracy are inevitable. In this study, the extension of a simulation model is considered by linear filtration efficiency of particles by cake layers in accordance with its thickness and a persistent slip of particles inside walls independent on accumulation of the particles. The entire behavior of particle emission calculated by the model was in a good agreement with experimental data which were obtained with miniature gasoline particulate filter samples and a synthetic particle generator.