A Study on the Causes of Diesel Injector Claims in India through Low-Pressure Fuel System Analysis

KEUNSOO KIM (Hyundai Motor)

This study analyzes the causes of diesel injector claims in the Indian market from the perspective of the low-pressure fuel system and fuel characteristics under low-temperature conditions. Injector claim rates exceed 1%, predominantly occurring in northern regions with harsh winters. Investigations reveal that fuel filter internal leakage caused by paraffin crystallization and structural weaknesses leads to injector malfunction. Comparative chamber tests confirmed filter leakage in specific filter types under cold conditions. Field tests in mountainous northern India supported these findings. Recommendations include structural improvements and heater application to mitigate leakage. This research contributes to enhancing diesel injector reliability in challenging climates.

Development of a Multi-Component Surrogate Model for Biodiesel Fuel

Sho Fukuda･Takashi Kawachi･Koji Momose (Toyota Industries)･Hideki Takase (IDAJ)･Tomohiro Hayashi･Toshiaki Hijima (SOKEN)

A multi-component surrogate model for biodiesel fuels was developed by separating liquid-phase and gas-phase surrogates based on actual fuel composition. This approach avoids complex conversion methods while preserving key reaction characteristics. The model integrates detailed chemical kinetics into CFD simulations and is validated against engine experiments, accurately predicting ignition delay, heat release, and emission trends. This method offers a practical tool for combustion and emission analysis across diverse fuel types, supporting carbon-neutral engine design.

Alcohol Diffusive Combustion Technique as an Alternative Diesel Combustion Forth Report
-Effect of reducing diesel fuel ratio in dual-fuel injection-

Yoshifumi Wakisaka･Teruaki Kondo･Kazuaki Nishikawa･Takayuki Fuyuto (Toyota Central R&D Labs.)･Kenji Date･Yusuke Ueda･Satoshi Sugawara (DENSO)

Alcohol fuel, namely methanol and ethanol, are promising fuel for diffusive combustion in heavy-duty diesel engines, while they are difficult to self-ignite. In this study, a prototype dual-fuel injector that injects diesel fuel as an ignition source from the same nozzle with ethanol was developed. By installing a small orifice into the diesel flow path and reducing the diesel proportion during the main injection, we demonstrated that smoke can be significantly reduced even under medium-load conditions where the diesel proportion is relatively high.

A Study on Factors Affecting Water Evaporation from Emulsified Oil in a Hydrogen Engine

Akemi Ito･Ryosuke Ichimura･Itsuki Motomiya (Tokyo City University Engine Research Laboratory)

Hydrogen engines produce more water than conventional fossil fuel engines, making oil emulsification more likely during winter operation. It was shown in authors' previous report that factors such as oil temperature and liquid surface area affect the evaporation of water from emulsified oil. This paper reports on the results of a new investigation into the effects of humidity and container shape, evaluating the contribution of each factor to the evaporation of water using multiple regression analysis.

Engine oil adhesion prediction technology as the core of intake system engine deposits

Aiko Kawakami･Shinichi Tanioka･Yoichi Kuji (mazda)

This report presents the results of testing the oil-repellent and slip properties between engine oil and the substrate using molecular dynamics and particle methods. By applying molecular dynamics methods, a desk-based verification model was developed to predict the tendency of engine oil mist, which triggers deposit buildup on intake system components, to adhere. This enabled the selection of coatings effective in suppressing adhesion and the consideration of formulations for engine oil additives.In addition, the behavior of oil mist was visualized using the particle method, and the validity of the adhesion suppression effect was examined.

Modeling Running-In Process of Engine Bearings with Roughness Evolution and Tribo-Film Effects

Kentaro Kawaguchi (Mazda)

Engine bearing friction characteristics change during operation as running-in progresses. Running-in is governed by coupled processes across scales, including surface geometry evolution, roughness changes, and tribo-film formation. Thus, it is difficult to model and often understood only empirically. In this study, we develop a model that simultaneously accounts for roughness evolution and tribo-film effects, enabling quantitative prediction of the bearing running-in process. The proposed approach offers improved interpretability of running-in mechanisms and provides a basis for rational design of sliding surface performance.

Investigation of Piston–Ring Dynamic Mechanisms Governing Ring Sealing and Flutter Analysis Technology

Junjiro Nakanishi･kouji Shishime･Masaki Fukuma (Mazda)

In this study, the relationship between piston secondary motion and ring flutter was clarified using a model whose prediction accuracy for ring behavior had been validated. Furthermore, it was demonstrated that piston secondary motion affects land pressures and thereby contributes to the onset of flutter.