A Study on Improving Methane Purification Performance of a Three-Way Catalyst by Lean / Rich Lambda Oscillation (2nd Report)

Toyofumi Tsuda･Kazuya Miura･Yuya Ito･Shota Yokoo･Fumikazu Kimata (Suzuki Motor)

Methane is one of main components of automobile exhaust and has 25 times higher greenhouse effect than CO₂. Methane is difficult to be purified by three-way catalyst (TWC) because of its stable chemical property. However, there is rich / lean lambda oscillation, methane purification rate is improved. In this study we clarified CO, NO, and H2O in the exhaust gases play a crucial role in improving the methane purification rate under lambda oscillations.

Air Path and Exhaust Aftertreatment Optimization for Medium-Duty Hydrogen Engines

Martin Weber･Thomas Spannaus･Hubertus Ulmer･Thaddaeus Delebinski (IAV)

For reaching the climate goals to slow down the global warming, an urgent decarbonization of the transport sector must be accomplished. Since hydrogen combustion engines emit pollutants like nitrogen oxides and unburnt hydrogen, emission aftertreatment systems will have to be implemented for future emission legislations like EU VII and Tier 5.
The proposed paper will present different exhaust aftertreatment technologies with focus on the impact of especially NOx and hydrogen slip. Investigations were carried-out with a holistic model-based simulation approach, using validated GT-Suite models as well as test bench results.

Analysis of Heated Urea Water Solution Spray in Urea Selective Reduction Catalyst Systems

Kentaro Inasaki･Yuta Kikugawa･Kanako Nishimura･Eriko Matsumura (Doshisha University)

In urea selective catalytic reduction systems under low exhaust gas temperature conditions, the urea is not decomposed completely and the NOx purification rate decreases. In this study, the urea water solution temperature was controlled to promote atomization, evaporation, and chemical reaction of the urea water solution spray. In this paper, the results of optical measurement analysis and the effect of heating on the atomization and phase change characteristics of the urea water solution spray are reported.

Analysis of Factors Affecting N₂O Formation and Proposal of System Design Guidelines in the Urea SCR System

Kasumi Yoneyama･Kenji Fujii･Teppei Ohori･Hisashi Ozawa･Naoya Ishikawa (Isuzu Advanced Engineering Center)･Hiroshi Anoda (Isuzu Motors)

In the urea SCR systems, nitrous oxide (N2O) by-production during NOx conversion is an issue. In this study, a sensitivity analysis is performed using a combination of five factors included in a plant model of a urea SCR system. By clarifying the factors that contribute to N2O formation, we propose a design guideline for the urea SCR system that can both improve the NOx conversion ratio and suppress N2O formation.

Development of GPF Based on Capillary GPF Model for Euro7 Regulation

Sungmu Choi･Jiho Cho･Sangmin Lee (Hyundai Motor)

To predict PN(Particulate Number) filteration efficiency and pressure drop of GPF, capillary models of two on-wall coated GPFs and one membrane GPF were developed. The microstructure of the GPF was taken into account by several capillaries that can represent pore size distribution and porosity in GPF.
Capillary models of on-wall coated GPF and membrane GPF were calibrated based on engine bench tests. Membrane GPF showed higher PN filtration efficiency and lower pressure drop compared to the on-wall coated GPF. Maximizing PN filteration efficiency of on-wall coated GPF based on its capillary model was investigated by removing cracks on coating layer. The effect of engine-out PN and PM(Particulate Mass) on GPF-out PN by its capillary model was investigated to meet Euro7 regulation. It was found that larger particle was more effective in reducing GPF-out PN than smaller one under the same engine-out PN conditions.

Development of Technology for Predicting the Activity of Exhaust Gas Purification Catalysts by the First Principle Calculations

Miura Kazuya (Suzuki Motor)･Hiroki Kusaba･Tomoya Miyoshi (Kumamoto University)･Hiroshi Yoshida (Kanazawa University)･Hiroyuki Tsuchizaki (Suzuki Motor)･Masato Machida (Kumamoto University)

This study proposes a technique to predict the catalytic activity using the first principle calculation. The proposed method consists of three parts. (1) Assume the detailed chemical reactions. (2) Estimate the activation energy (Ea) for each reaction by the first principle calculation. (3) Input estimated Ea values into the simulation software for chemical kinetics (e.g. exothermia-suite). The validity of proposed method was evaluated. This study predicted the catalytic activity of Rh (111) surface for CO-NO-O2 reaction. The predicted results reproduced well the experimental results of the Rh thin-film catalyst, which was prepared by the "arc plasma method".

Study on PN Characteristics by Type of Damaged DPF for Diesel Vehicles Operating in the IDLE Condition

Jaeun Yoo･Giyoung Park･Sujeong Jang･Seangwock Lee (Kookmin University)

Road traffic is one of the biggest cause of urban air pollution, and particulate matter(PM) emitted from diesel vehicles is harmful to respiratory health. In some countries, there is a trend to regulate PM emissions from diesel vehicles during periodic technical inspections. A project to attach an exhaust gas reduction device was carried out in Republic of Korea, but the Retro-fit DPF is known to be less efficient in reducing pollutants in the exhaust gas due to poor management. In this experiment, the damaged DPF was installed on the test vehicle and the PN characteristics emitted were compared and analyzed.