Multi-Point Heat Flux Measurement and Evaluation of Abnormal Combustion Effects in Direct-Injection Hydrogen Motorcycle Engines

Shoki Mashiko･Masakuni Oikawa･Yuji Mihara･Yuki Kaga･Aoshi Yokomori (Tokyo City University)･Takumi Iwata (MOTORA)･Hiroshi Kato･Kyohei Izumi (Kawasaki Motors)･Kenichi Sano (Honda Motor)･Tomohiko Kamio (Yamaha Motor)

Four heat flux sensors were installed on the cylinder head of a direct-injection hydrogen motorcycle engine, and transient heat flux measurements were carried out over a wide engine speed range from 2000 to 10000 rpm. In addition, heat flux behavior under abnormal combustion conditions at high engine speeds was successfully captured. Based on multi-point simultaneous measurements, this study elucidates the heat flux characteristics at high engine speeds and evaluates the influence of abnormal combustion on wall heat load.

An Investigation of Abnormal Combustionj Induced by Abnormal Electrical Discharge in a Direct-Injection Hydrogen Engine for Motorcycles

Hiroshi Kato･Kyohei Izumi･Yoshinori Nakao･Yusaku Matsumoto･Satoaki Ichi (Kawasaki Motors)･Tomohiko Kamio (Yamaha Motor)･Yoshinari Ninomiya (Suzuki Motor)･Kenichi Sano･Yusuke Marui･Takashi Kondo (Honda Motor)

Abnormal combustion phenomena, such as pre-ignition and knocking, are critical issues in the development of hydrogen engines for achieving carbon neutrality. In this study, the occurrence of abnormal combustion caused by abnormal electrical discharge was investigated in a direct-injection hydrogen engine for motorcycles through in-cylinder visualization and measurements of the secondary ignition voltage.

Analysis of the Effect of Hydrocarbon-Hydrogen Mixture on Flame Propagation Characteristics Using In-Cylinder Visualization

Tomohiro Nakamura･Takuya Hotta･Ryosuke Suda･Takamori Ueno (Nihon University)･Yoshinori Nakao (Kawasaki Motors)･Koichiro Matsushita (Honda Motor)･Tomohiko Kamio (Yamaha Motor)･Yoshinari Ninomiya (Suzuki Motor)･Akira Iijima (Nihon University)

In this study, we investigated the effect of hydrogen-hydrocarbon mixtures on combustion characteristics using in-cylinder visualization experiments and pressure analysis. The flame behavior was recorded using a high-speed camera and analyzed. As a result, mixing hydrogen improved flame propagation speed. Additionally, ignition characteristics were enhanced, resulting in earlier heat release rates and more stable combustion.

Study on a Two-Stage Hydrogen Engine Employing Diluted Stoichiometric-Combustion with 100% EGR of Lean-Combustion Exhaust Gas

Dengpei Chen･Yasu Moriyoshi･Takeshi Ishida･Tatsuya Kuboyama (Chiba University)･Hideki Kato･Hideaki Osada･Tomoyuki Sato (Hino Motors)･Keiso Takeda (Enable)

To realize zero emissions, simultaneous reduction of CO2 and NOx emissions from internal combustion engines is required. In this study, a two-stage hydrogen engine system enabling the application of a TWC was proposed through simulations using diluted stoichiometric combustion with 100% EGR of lean-combustion exhaust gas. Based on the simulation results, a prototype engine based on a four-cylinder diesel engine was developed for further investigation.

Optimization of Combustion Chamber Geometry for Direct-Injection Hydrogen Engine Using Mixture Formation Analysis and Machine Learning

Kentaro Minoda (Tokyo City University)･Nobuhiro Shimmura (Tokyo City University/Kawasaki Heavy Industries)･Masakuni Oikawa･Shota Tsukamoto (Tokyo City University)･Sekai Miyamoto (Kawasaki Heavy Industries)･Yuji Mihara･Yasuo Takagi (Tokyo City University)

To achieve high thermal efficiency and low emissions in hydrogen engines, optimization of mixture formation, including combustion chamber geometry, is essential. In this study, three indices, including mixture homogeneity, were defined to evaluate mixture formation, and combustion chamber geometry was optimized by quantitatively assessing these indices using machine learning. Furthermore, the validity of the proposed approach was experimentally validated.

Study of jet behavior and mixture formation processes in hydrogen engines

Ken Ayukawa･Akichika Yamaguchi･Seiya Nishimura･Satoru Sasaki･Masanori Goto･Kazufumi Serizawa (DENSO)

Hydrogen engines are a promising option for achieving carbon neutrality, but improving the homogeneity of the air-fuel mixture is a challenge in achieving both abnormal combustion avoidance and high power/low NOx emissions. In this study, we focused on the air-fuel mixture formation mechanism within the engine cylinder and clarified the injection and jet requirements necessary for homogeneous mixture formation through CFD analysis and engine test.