Many research institutes are pursuing research on homogenous-charge compression ignition (HCCI) engines, which offer higher thermal efficiency than gasoline engines at low and medium loads and produce fewer emissions than diesel engines. However, the ability of HCCI engines to operate at high loads is limited by the rate of pressure rise rate and knocking, while their ability to operateat low loads is limited by combustion efficiency. This article describes the basic characteristics of HCCI engines running on natural gas, and technologies for increasing their output. Natural gas has a higher ignition temperature than gasoline or light oil, generally around 1050K. Supercharging was found to be an effective way of increasing output, and a brake mean effective pressure of 0.98 MPa, thermal efficiency of 43.3% and NOx emissions concentration of13. 8ppm were obtained with a 4-cylinder gas engine.
Global shipping uses Heavy Fuel Oil (HFO) as the primary fuel. HFO is a mixture of oil refinery residue and cutter stock, hence it contains large numbers of hydrocarbons with a wide range of molecular weights and dissimilar structures. Conventional thermodynamics modelling techniques are inadequate for HFO vaporisation modelling. The present article summarises continuous thermodynamics vaporization models along with chemical kinetics models for decomposition and polymerisation, and soot burnout models, employed to study the behaviour of HFO spray combustion. A sample of HFO is also characterised in the laboratory using chemical characterisation procedures including sequential elution solvent chromatography, gas-chromatography mass spectrometry and elemental analysis, to obtain the composition and mean molecular weights of HFO fractions required for continuous thermodynamics modelling. Models are implemented via subroutines in a diesel spray simulation in the CFD package STAR-CD. The simulation is applied to a constant volume spray combustion chamber. The present model accounts for the formation and burnout of liquid phase soot in diesel engines. This soot will be emitted as Black Carbon if unburnt. The models are examined for two representative fuel samples; one with the good combustion quality and the other with poor. Good qualitative agreement is shown between the simulations and published experimental data.
OILMISTDETECTOR (OMD) is an apparatus which measures oil mist level in the engine crankcase to avoid crankcase explosion． It is known that crankshaft damage due to main bearing problems results in long-term stoppage of vessel． Since oil mist is detected during such problems， the authors propose to utilize OMD as an early warning device to prevent main bearing damage by lowering its alarm level． conducted on a vessel to achieve the study’s purpose
Researches show that 86% of collisions are due to improper lookout despite the existence of many navigational tools on board ship. A stereo imaging system is proposed to improve navigational safety. A ship is in an extremely dynamic environment. There are many parameters which may degrade the system quality such as ship motion (rolling, pitching, and yawing), vibration due to strong winds and structural vibration. In this paper, we focus on applying the system to such a dynamic environment. Firstly, a principle to measure 3D location of an object under unstable conditions on board ship is described. It includes estimating the rolling and pitching angles of the ship to eliminate the negative effects of such movements and calculating the relative camera orientations for accurate 3D calculation of detected objects. Finally, details of sea-sky line detection from sea images to obtain the rolling and pitching angle of the ship is described.
The temperature dependence on radiation induced surface activation (RISA) corrosion control effect for stainless steel was examined in artificial and natural seawater in this paper. The results obtained are as follows: 1) The RISA effect was evident up to 30 °C, but was hardly recognizable over 45 °C. 2) The RISA effect was observed regardless of the seasons, and the anodic current decreased with increase in the temperature. 3) It was confirmed that corrosion control mechanism proposed in the previous paper was appropriate. The increase of dissolved oxygen was measured in natural seawater by the appearance of RISA effect.
With adequate and detailed information, a large plant operator can generally maintain a plant’s good working condition. A ship engineer has the samework as a plant operator except that self-sufficiency at sea is a requirement for ship engineers. On the basis of the cognitive process of human activities, Rasmussen proposed three different modes which are the knowledge-based mode, the rule-based mode, and the skill-based mode. One important but complex feature is to understand howto conduct the plant operator shift between eachmode. On the other hand, E.R.M. was adopted by the IMO and will be introduced in engineer training programs. In this paper, group discussion was introduced as an effective leaning method. It was explored whether learning through group discussion was connected with the acquisition of management capabilities in E.R.M. The result verifies the effectiveness of groupdiscussion in learning E.R.M. techniques.