Development of Mitsubishi UE Marine Diesel Engine
Masahiko Okabe
Mnager, Hamburg Representative, Mitsubishi Heavy Industries Europe, Ltd.
1. Introduction
There are currently only 3 brands of low-speed 2-cycle marine diesel engines available: the Mitsubishi UE engine, the WARTSIRA NSD-RTA engine, and the MAN-B & W-MC engine. Mitsubishi UE engines have been acclaimed by many ship owners, both in Japan and around the world. To maintain the good reputation of MHI's engines, it is necessary to keep improving and developing them to meet the requirements of the time.
We would like to introduce some of UE engine development technologies at MHI, and also explain 3 engine models, the UEC 37LS II, the UEC 43LS II and the UEC 52LSE, all of which have been recently placed on the market.
2. Target of development
In the initial stage of development, it is necessary to understand what the market is wanting. According to the needs of the market, MHI has developed numerous types of UE engines. Figs.1 and 2 show the development history of UE engines.
In the conventional development of engines, emphasis has been mainly put on improving fuel consumption and increasing engine output. Output factor (Pme ･ Cm) and the maximum pressure (Pmax) in the cylinder are steadily increasing. In this respect, engine operating conditions are becoming more and more severe.
Recently, requirements have been changing in response to the issue of environmental protection. This will become a critical issue for marine engines, which currently are not regulated, in contrast to land-use engines and their many regulations. It is necessary to enhance reliability as well as to provide technical expertise for environmental protection.
In short, the requirements are engine output, speed, easy installation, and a minimized engine room suitable for the type of ship planned by the shipyard. A reliable engine allowing easy handling and maintenance must be provided to the ship owner. In the near future, an engine compatible with electric control systems should be developed.
3. Various technologies for development
MHI believes that continued development of elemental technologies in each field and accumulated expertise can result in a better engine. We would like to introduce some examples of MHI's elemental technologies.
3.1 Combustion technology
1) Scavenging simulation
After the air required for combustion is compressed by the turbo-charger, it is cooled with an air cooler. It is then supplied to the cylinder through the scavenging port provided under the cylinder liner. Fresh air comes into the cylinder, discharging any exhaust gas remaining in the cylinder, and at this time fresh air should not be allowed to mix with the residual exhaust gas. Such gas replacement must be
