Influence of injection parameters on the transition from PCCI combustion to diffusion combustion in a small-bore HSDI diesel engine

In this paper, the influence of injection parameters on the transition from Premixed Charge Combustion Ignition (PCCI) combustion to conventional diesel combustion was investigated in an optically accessible High-Speed Direct-Injection (HSDI) diesel engine using multiple injection strategies. The heat release characteristics were analyzed using incylinder pressure for different operating conditions. The whole cycle combustion process was visualized with a high-speed video camera by simultaneously capturing the natural flame luminosity from both the bottom of the optical piston and the side window, showing the three dimensional combustion structure within the combustion chamber. Eight operating conditions were selected to address the influences of injection pressure, injection timing, and fuel quantity of the first injection on the development of second injection combustion. For some cases with early first injection timing and a small fuel quantity, no liquid fuel is found when luminous flame points appear, which shows that premixed combustion occurs for these cases. However, with the increase of first injection fuel quantity and retardation of the first injection timing, the combustion mode transitions from PCCI combustion to diffusion flame combustion, with liquid fuel being injected into the hot flame. The observed combustion phenomena are mainly determined by the ambient temperature and pressure at the start of the second injection event. The start-of-injection ambient conditions are greatly influenced by the first injection timing, fuel quantity, and injection pressure. Small fuel quantity and early injection timing of the first injection event and high injection pressure are preferable for low sooting combustion.     

The Northwest Passage: A simulation

We model shipping through the Northwest Passage in northern Canada in order to see if reported recent ice thinning has made this route economic relative to the Panama Canal. Container shipping between Yokohama to New York and St. Johns, Newfoundland is simulated by VSLAM for the two routes using bluewater ships for the Panama Canal and identically sized Canadian Arctic Class 3 (CAC3) ships for the Northwest Passage. Each route is broken into a series of logical legs, and environmental conditions and wait times are assigned. Ice conditions are modeled from historical records. Average speed through the Northwest Passage shows little seasonal variation. Round trips per year are higher through the Northwest Passage. The required freight rate (RFR) to recover all costs including capital recovery is calculated. RFR is slightly lower for the St. Johns to Yokohama transit using the Northwest Passage, and higher for the New York to Yokohama route, as compared to the Panama Canal. Possible future thinning of Arctic ice would further improve the economics of the Northwest Passage.     

The British port transport industry Part 1. Operational structure, investment and competition

Abolition of the National Dock labour Scheme in July 1989 has intensified competition in Britian's ports and allowed the major port authorities and other port operators to restructure their operations and develop new investment plans. But the result has been to add to excess capacity in the industry and to porduce a 'zero-sum' process of traffic redistribution between Britain's driven largely by customer demands for lower charges.