In high turbocharged-type diesel engines, on occasions when there is a drastic change in the engine load there is an associated delay in the engine response due to the momentary lack of intake air. In such instances this results in a decrease of engine speed and production of visible smoke, particularly in the main propulsion system. In order to address the problems above, the Rootsblower system was tested. The Roots-blower has rotors driven by a motor which expel air to boost intake air of the engine. The tests did show some improvements to engine response times and smoke opacity levels. However, the application of this system presented its own set of problems. Next we considered the Jet-assist system. This system uses pressurized air which is injected into the compressor wheel of the turbocharger in order to increase air flow and boost pressure. We conducted elaborate simulation tests of this system on land. The actual change of propeller shaft torque and response of engine speed were measured on board beforehand. The test engine was a 4 cycle medium speed main propulsion type with reduction gear, coupled with a fast control type dynamo meter. Then we tested a variety of air pressures, terms and timings of the Jet-assist, and the performance under each variable was measured. Optimizing the conditions based on the test data, we were able to drastically improve engine speed recovery time and smoke concentration in instances of rapid engine load increase. The system was then installed on the main engine of an actual ship. Plentiful data and experience obtained from the shop tests helped us establish optimum conditions on the ship with only little tuning. On the actual ship, we also significantly improved the load responsiveness and smoke concentration when the clutches were engaged. In addition, we also established that the Jet-assist system is effective in reducing smoke production during engine start-up and acceleration.
Improvements to transient response times and decreased smoke production in medium speed marine propulsion diesel engines
2010
8 Seiten, 24 Bilder, 3 Tabellen
Conference paper
Storage medium
English
Medium-speed diesel engines for marine propulsion
Engineering Index Backfile | 1965
|Transient response model of low-speed marine diesel engines for propulsion system simulation
British Library Conference Proceedings | 1993
|SMOKE EMISSIONS FROM MEDIUM-SPEED DIESEL ENGINES
British Library Conference Proceedings | 2001
|Marine medium speed diesel engines
TIBKAT | 1991
|Marine propulsion by diesel engines
Engineering Index Backfile | 1931
|