Cyclic variability (CV) in lean HCCI combustion at the limits of operation is a known phenomenon, and this work aims at investigating the dominant effects for the cycle evolution at these conditions in a multi-cylinder engine. Experiments are performed in a four-cylinder engine at the operating limits at late phasing of lean HCCI operation with negative valve overlap (nvo). A combustion analysi...

Youth suicide is a serious, yet preventable, public health concern for ethnic minorities and rural communities. This paper describes the youth leadership model utilized by Hawai‘i’s Caring Communities Initiative (HCCI) and provides reflections on the important factors for success in implementing a youth and community advocacy project for youth suicide prevention. HCCI partnered with six youth a...

Abstract In the current study, electrolytic deposition using two different electrodes, copper (Cu) and nickel (Ni) was investigated with aim of protecting worn surface during mechanical sectioning polishing, for a posterior examination sub-surface microstructure. The efficacies coatings were visually assessed based on its adhesivity ability to protect wear tracks an as-cast 26% Cr high chromium...

Three-dimensional time-dependent CFD simulations of autoignition and emissions are reported for an idealized engine configuration under HCCI-like operating conditions. The emphasis is on NOx emissions. Detailed NOx chemistry is integrated with skeletal autoignition mechanisms for n-heptane and iso-octane fuels. A storage/retrieval scheme is used to accelerate the computation of chemical source ...

The alternative HCCI combustion mode presents a possible means for decreasing the pollution with respect to the conventional gasoline or diesel engines, while maintaining the efficiency of a diesel engine or even increasing it. This paper investigates the possibility of using gasoline in an HCCI engine and analyses the auto-ignition of gasoline in such an engine. The compression ratio that has ...

In order to understand better the auto-ignition process in an HCCI engine, the influence of some important parameters on the auto-ignition is investigated. The inlet temperature, the equivalence ratio and the compression ratio were varied and their influence on the pressure, the heat release and the ignition delays were measured. The inlet temperature was changed from 25 to 70 °C and the equiva...

Low-temperature combustion modes have attracted global attention in recent years, especially the homogeneous charge compression ignition (HCCI) mode. The HCCI produces high-speed combustion, achieving relatively high thermal efficiencies while emitting low NOX and soot. However, due to lack of direct control start one main challenges this type engine is ensure that auto-ignition occurs close to...

  This paper presents a modeling study of a CNG Homogenous Charge Compression Ignition (HCCI) engine using single-zone and multi-zone combustion models. Authors' developed code could be able to predict engine combustion and performance parameters in closed part of the engine cycle. As detailed chemical kinetics is necessary to investigate combustion process in HCCI engines, therefore, GRI-m...

New HCCI/CAI Combustion Process Development: Methodology for Determination of Relevant Fuel Parameters — To pass the simultaneous emission requirements for near zero pollutant and low CO2 levels, which are the challenges for future powertrains, many research studies are currently carried out over the world on new engine combustion processes, such as controlled auto-ignition (CAITM) for gasoline...