Infrared High-Speed Thermography of Piston Surface on Diesel Engine

Kazuya Miyashita･Shinya Furukawa･Yoshinori Ishii･Hisashi Ozawa (Isuzu Advanced Engineering Center)

Combustion CFD reproduces in-cylinder combustion by combining models representing each phenomenon. However, there are issues with the accuracy of these models, in particular, verification of wall heat loss is necessary. In this study, in order to verify the accuracy of wall heat loss model, measurement of wall surface temperature distribution was attempted in a top-view optical engine. Infrared radiation from the piston surface impinged diesel spray flame was directly visualized by using the high-speed infrared camera. The obtained infrared images showed the potential for high-speed measurement of wall surface temperature distribution.

NOx Reduction Strategy Using Direct Water Injection in a Diesel Engine (Second Report)
-pplying the In-Cylinder Water Stratification Concept to Higher Load Conditions-

Kazuhisa Inagaki (TOYOTA CENTRAL R&D LABS)･Tsutomu Kawae (TOYOTA INDUSTRIES CORPORATION)･Teruaki Kondo･Kazuaki Nishikawa (TOYOTA CENTRAL R&D LABS)

We proposed a combustion concept that significantly reduces NOx emissions by stratifying water within the engine cylinder. In this second report, engine performance was evaluated under higher load conditions with an IMEP of 1.2 MPa. It was demonstrated that, under conditions where the water injection volume was 50% of the fuel amount, optimizing the division of water injection, injection timing, and intervals resulted in approximately a 40% reduction in NOx at equivalent soot concentration levels.

Thermal Efficiency Improvement for a High-compression-ratio HD Diesel Engine by Utilizing an Offset Orifice Nozzle

Tomoyuki Mukayama･Noboru Uchida (New A.C.E Institute)

It has been necessary to investigate into thermal efficiency improvement and fuel spray characteristics aiming to achieve it for commercial heavy-duty diesel engines. This study focuses on the simultaneous improvement in cooling loss and indicated thermal efficiency by means of an offset orifice nozzle presented in the former study, and investigates further into combustion and emission characteristics of a high-compression-ratio heavy-duty diesel engine equipped with offset orifice nozzles. Internal nozzle flow analysis by numerical simulation and in-cylinder combustion visualization were also carried out to identify the cause of significantly different combustion phenomena.

Model analysis of the concentration distribution in the spray and wall interference in high compression ratios (high ambient density field) in diesel engines

Ryoto Yoshikawa･Yuki Yasuno･Eriko Matsumura･Jiro Senda (Doshisha Univ.)

Increasing the compression ratio in diesel engines improves thermal efficiency. However, the higher gas density in the cylinder changes the flame wall impingement pattern and affects the cooling loss, so the combustion chamber shape must be optimized. In this study, the combustion chamber shape for heavy duty vehicle diesel engine is optimized by model analysis.

Modeling of Fuel Spray-Wall coated Lubricating oil Interference in Compression Ignition Engines

Yuki Nakata･Shoto Nakaoka･Kanako Nishimura･Eriko matumura (Doshisha Univ.)

Oil dilution during post-injection is a problem in compression ignition engines. However, existing models cannot adequately account for the impingement of fuel droplets on wall coated with lubricating oil film. In this study, authors developed new spray impingement model that considers impingement of fuel droplets and lubricant oil film. In addition, the applicability of the model was verified through experimental results and comparisons with other models.

Evaluation on the Exhaust Behavior of a Diesel Light Duty Vehicle by On-Board Alternative Analyzers.

Noritsune Kawaharada･Hisakazu Suzuki (NALTEC)

The target substances in the Real Driving Emission (RDE) test are mainly CO2 and NOx. Additionally, due to its high global warming potential, N2O is also a focus in this study. Alternative measurement principle analyzers, different from the commonly used non-dispersive infrared (NDIR), non-dispersive ultraviolet (NDUV), and chemiluminescence detection (CLD) methods, were applied for the measurement of diesel light-duty vehicle emissions. The exhaust behavior of the diesel light-duty vehicle has been evaluated under several temperature conditions, and the variance in the emission results from the different measurement principles has been discussed.