尿素SCRシステムにおける尿素水衝突板加熱時のアンモニア生成特性の解析

石井　徹・中川　研吾（同志社大学院）・松村　恵理子（同志社大学）

尿素SCRシステムにおいて排気温度が低温となる運転条件では，尿素水からアンモニアへの分解生成量が不十分となり，NOx浄化性能が低下する．本研究では尿素水衝突板の加熱制御を実施し，低温排ガス条件下におけるアンモニア生成量の効果について実験解析を実施した．その結果を報告する．

大型車両向け低圧損・低コストDPFのための先進材料と再生制御

千々岩　涼子（コーニングインターナショナル）・Krishna Aravelli・Suhao He（コーニング）

本研究は，大型車両用ディーゼル微粒子フィルタ（DPF）の材料設計と再生制御を最適化し，捕集効率を維持しつつ圧力損失とコストを低減する手法を提案する．実験とシミュレーションにより捕集性能と圧力損失およびスス容量のトレードオフを評価し，将来の後処理システム最適化に資する知見を提供する．

Exhaust Gas Velocity Distribution Analysis Method Using Temperature Distribution and Heat Transfer Characteristics of Catalytic Converters

Jiho Cho･Hyungjun Kim･Sungmu Choi･Jaegyung Yoon･Changwan Hong･Sangmin Lee (Hyundai Motor)

This study proposes a method to measure exhaust gas velocity distribution at a catalytic converter inlet by analyzing transient temperature changes during warm-up. Unlike direct velocity measurements, this approach infers velocity profiles from temperature responses affected by thermal capacity. Experiments under various conditions validate its accuracy and feasibility. The method offers a novel way to assess flow uniformity, providing valuable insights to enhance catalyst design and performance.

Development of an Exhaust System Complying with Tier 4 PM Regulations through Study of PM Formation Mechanisms in the Exhaust System

Sungmu Choi･HyeongJun Kim･WonSoon Park (Hyundai Motor)

The U.S. Tier 4 regulation imposes a more stringent particulate mass (PM) limit of 0.5 mg/mile, with enforcement scheduled to commence in 2027. The experimental results revealed considerable variability in PM measurements obtained via filter paper, with occasional exceedances of the Tier 4 PM threshold. This phenomenon is hypothesized to result from the interaction between soluble exhaust gases, produced from the catalyst, and condensate water within the exhaust system, leading to PM formation. As exhaust temperatures rise, the evaporation of condensate water is believed to release the formed PM into the exhaust stream. The following strategies can be proposed to comply with Tier 4 particulate matter (PM) regulations: 1) implementation of high-efficiency GPF for PM reduction, 2) Utilization of additional catalyst to mitigate soluble exhaust gases, 3) elimination of semi-volatile compounds deposited in the exhaust system and measurement apparatus that may be converted to PM.

Study on the Degradation Mechanisms of North American Canisters

Seungyub Lee･Keunsoo Kim･Seunghwan Park (Hyundai Motor)

This study analyzes degradation in automotive fuel vapor canisters compliant with North American ORVR regulations. ORVR strictly limits refueling emissions and requires working capacity exceeding non-ORVR systems. Activated carbon drives vapor adsorption, so capacity loss risks noncompliance. We examine whether temperature swings during repeated adsorption-desorption cycles cause material deformation and thermal shock that accelerate degradation. Additional factors, including fuel intrusion and condensation, are assessed for effects on capacity and durability. Finally, we outline research needs to quantify degradation, refine materials and designs, and develop accelerated tests and models that ensure long-term performance, reliability, and regulatory conformity of fuel canisters overall.