Auxiliary Diesel Engine Research Articles

ヤンマーの低ＮＯｘ化技術

Middle speed diesel engine (EcoDiesel SAVETEN) was developed in order to achieve very low fuel consumption and meet the IMO NOx regulation. Generally, the fuel consumption and smoke generation should be increased when NOx emission is reduced. This also means that the production of CO2 (a so-called green house gas) will increase. This is one of the most difficult subjects on engine development. But EcoDiesel SAVETEN has realized“lower fuel consumption”and“lower NOx emissions”at the same time, without causing a increase in smoke emission.We thought out a new combustion concept for lower fuel consumption without increasing maximum cylinder pressure and injection pressure by using a simplified cyclic simulation. In order to realize the new combustion concept, the newly designed fuel injection system, combustion chamber and intake&exhaust system were applied. This com-bustion system is called the ASSIGN (Available Space Scattering Injection Geometric Nexus) combustion system. This realized the 10g/kWh lower fuel consumption than the conventional engines on the equivalent NOx emissions. And this is applied to the marine auxiliary diesel engines from 360kW to 3500kW.This is one of the YANMAR' s solutions for the marine environmental protection.

Operation experience of a solar- and wind-powered desalination demonstration plant

The present work outlines the designing, erection and operation process of a stand-alone desalination plant powered by both solar photovoltaic and wind energy. Such a plant will serve small isolated communities in remote areas devoid of water resources. A specially customized code was built to simulate the operation of the installation in order to allow appropriate choice of components specifications. Site meteorological data were used to enhance prediction capabilities. The code continuously updates the instantaneous water lever of the reservoir as well as the current state of charge of the accumulators. Depending on these two variables, a logical decision tree is built to decide whether the cumulated wind and solar energy production can satisfy the load of the plant or additional energy must be provided from the accumulators or an auxiliary diesel engine generator. The process control system for such an installation must allow for operation in isolated areas where qualified maintenance personnel are scarce or remote. These are special considerations regarding the design philosophy in order to reach a state as close as possible to a maintenance-free system. In view of this consideration, several layers of back-up were built into the system such as a diesel generator (whose use is to be kept to a minimum). Also, the system has been designed to operate at about a 33% service factor. Two-day battery storage autonomy has also been provided. The desalination plant uses reverse osmosis technology. The plant has a maximum product capacity of 9 m 3/d in view of future needs, even though it is designed to currently produce only 3 m 3/d. The inlet water is to be provided from on-site brackish water wells. The local water quality is approximately 3500–5000 ppm corresponding to brackish water. The system has been designed based on the premise that the average on-site wind velocity is about 4–5 m/s and an isolation level of about 5–5.5 kWh/m 2/d. The expected life-span of the plant is about 15 years. The system was successfully erected and has been continuously operated producing 3 m 3/d. Experimental measurements are now in progress, and a comparison to theoretical predictions is presented. The time schedule for the whole project consisted of 6–8 months, including many changes required during construction.

中速中小形ディーゼル機関における低質油燃焼

Today the auxiliary diesel engines on the ship use the degraded fuel oil of 3500 sec or equivalent Redwood No. 1 at 100°F.The authors have conducted a study on the reliability and the durability of small or mediumsized medium speed diesel engines burning the low grade fuel oils.In order to evaluate the combustion tests of degraded fuels, the ignition lag and the combustion mode of those fuels are analyzed by the combustion pressure measured at the fire side of the combustion chamber.The test engine is medium speed engine with 240 mm bore. The maximum power is 1125 PS at 720 rpm.The test fuels are light cycle gas oil (LCGO) from catalystic cracking units, and residual low grade heavy fuel of 3500 sec or equivalent RW. No. 1 at 100°F from the vacuum distillation etc.It is confirmed that the ignitability of LCGO and the combustion characteristics of residual low grade heavy fuel are inferior to those of marine diesel oil from the straight distillation.

中形漁船における主機駆動発電の経済性

Generally the specific fuel consumption of electric generator diesel engines, which are normally smaller, are more than that of propulsion diesel engines. So, it is said that shaft driven generator systems is effective to reduce the fuel consumption of ships.By the way there are wide variety of fishing methods and different types and many sized fishing boats. Power output of propulsion engines and generators of fishing boats varied in accordance with the kind of fishing, and their load varies widely by the operating condition.So, author selected following seven model fishing boats from the so called medium-size fishing boats to compare fuel economy of the shaft driven generator systems with that of the auxiliary engine driven system.1. Squid fishing boats (99GT)2. Skipjack pole and line fishing boats (79GT)3. Tuna long liners (79GT)4. Tuna long liners (99GT)5. Salmon drift net boats (97GT)6. Small offshore trawlers (65GT)7. One boat purse seiners (80GT)And author also selected following two systems as the shaft driven generator systems of the above boats.1. Direct drive system (propulsion engine is running constant speed and boat speed is controlled by controllable pitch propeller.)2. Thyristor/inverter systemModel operating patterns of these fishing boats during one year were established and calculated their fuel consumption on several generator driven system.Direct drive system was found ineffective for fuel saving except salmon drift net boat and one boat purse seiners. Thyristor/inverter system obtained 0.5-2.0% fuel economy. However in consideration with the initial cost, for medium-size fishing boats, shaft driven generator systems were not economical in comparison with auxiliary diesel engine driven generator system.

超音波を利用した燃料油改質装置とその実施例 (その1)

As petroleum refining techniques have developed, the quality of marine fuels has been declining. This has posed increasing difficulties in the treatment of fuel oil for diesel engines.In these circumstances, the fuel oil reformer, which uses ultrasonic technology, has several advantages, its principal advantage is that the ultra-sonic energy disperses the sludge suspended in the lower grade heavy fuel into superfine particles. This improves combustion in the diesel engine.This paper gives a comprehensive description of the structure and characteristics of the Fuel Oil Reformer. Results of actual operation of an auxiliary diesel engine with this equipment using heavy fuel oil is also discussed. Tests were conducted on the high seas.

Noise reduction on a Rhine-cruise ship due to damping material

In order to attenuate the structure-borne sound generated by the resiliently mounted auxiliary diesel engines and propagated via the decks to the passenger cabins of a Rhine-cruise ship, two decks and the hull between them were treated with 400 m 2 elasto-dissipative material. Measurements of the sound pressure levels in a cabin, situated between these decks, and vibration measurements, carried out both before and after the application of the damping material, indicated only small level reductions. The reduction caused by completion of the fitting out of the ship, however, appreciably exceeded the influence of the damping material. The usefulness of the application of damping materials on board a ship is therefore considered to be doubtful.