Numerical Modeling for Control to Achieve Early Activation of Urea SCR Catalysts by Electric Heating

Hayato Kojima･Reon Aoki･Tomoki Sakurai･Jin Kusaka (Waseda University)

An electrically heated catalyst (EHC) was installed in front of the SCR catalyst to improve the NOx conversion rate by increasing the temperature of the exhaust gas. Based on the characteristics of the exhaust gas, such as flow rate, temperature and composition, a numerical model for control was developed to calculate the power applied to the EHC required to bring the exhaust gas at the SCR catalyst inlet to the target temperature. The model enabled to raise the temperature of the exhaust gas with a maximum error accuracy of 3%.

Concept and Verification of Cold Emission Reduction Technology through Exhaust Path Reaction Control

Xiyao Ge･Ran Nishikido･Yoshitomo Takahashi･Tsugio Fukube･Daichi Takashima (Mazda)

Against the backdrop of stricter emission regulations, reducing emissions during the initial cold start phase when the catalyst is inactive has become an urgent task. In this study, we conceptualized a technology to control the temperature and concentration fields within the exhaust path to promote oxidation reactions. Through single-cylinder engine tests, we confirmed that this technology has the effect of reducing HC, CO, and NOx emissions by 70-90% compared to conventional methods.

Study on the Post-Oxidation Mechanism of Unburned Hydrocarbon Species inside the Exhaust port and manifold of Gasoline Engine.

Masahisa Yamakawa･Tatsuya Fujikawa･Daisuke Shimokuri･Keisuke Yamamoto (Hiroshima University)･Kenji Uchida･Jyunki Hori･Naoki Yoshioka･Kaede Shirane (Mazda)･Akira Miyoshi･Yoshiki Sho (Hiroshima University)

In order to achieve zero emissions of harmful substances (Zero EM), it is necessary to reduce not only unburned hydrocarbons (HC) during cold starts but also the intermittently emitted difficult-to-clean HC from the latter half of the catalyst warm-up process. Therefore, we introduced technology to measure the gas components and temperature inside the exhaust pipe with high time resolution to analyze their generation and post-oxidation. We investigated the effects of mixture formation and other factors on these emissions.

Proposal of a Compact Aftertreatment System Integrating Exhaust Gas Adsorption, Conversion and Particle Filtration Functions

Masashi Matsumoto (JARI)･Katsunori Hanamura (Sophia University / Japan Science and Technology Agency)･Takashi Ogi (Hiroshima University)･Kohei Kume (Waseda University)･Masahiko Matsukata (Waseda Univeresity)･Takaaki Kitamura (JARI)

An exhaust aftertreatment system with high performance and compact is required to meet stringent emission regulations and to reduce installation space. In this research, we have proposed a functionally integrated exhaust aftertreatment structure, in which three-way catalyst particles and hydrocarbon absorbent particles are layered on a wall-flow monolith. In this report, a concept of exhaust gas purification of this aftertreatment structure was demonstrated, and various results for further improvement of performance were introduced.

Experimental Analysis of Ammonia Generation Characteristics by Heated Urea Water Solution Spray in SCR Systems

Tetsu Ishii･Kengo Nakagawa･Eriko Matsumura (Doshisha University)

In SCR systems under low exhaust gas temperature conditions, the urea is not decomposed to ammonia completely and the NOx purification rate decreases. In this study, the effects of urea water solution heating control on ammonia production under low exhaust gas temperature conditions through experimental analysis are reported.