Measurement on PM Emission from 2-Cycle Marine Diesel Engine during Voyage
Kazuyuki MAEDA*, Koji TAKASAKI**, Shin-ichi MORISHITA* and Hiroshi MATSUSHITA*
In order to establish the measuring method of PM (particulate matters) emission from marine diesel engines during voyage, following two experiments were carried out.
(1) Trial to measure the PM emission from a 2342 GT experimental ship equipped with a 2795 kW 2-cycle marine diesel engine and a controllable pitch propeller.
(2) Examination on the measuring procedure of PM emission using a high-speed test engine.
For both the ship and the test engine, a partial-flow dilution tunnel was applied. Results obtained from the examinations are as follows.
(1) According to the measured PM data from the experimental ship, the higher the engine load was, the more PM (g/kWh) were emitted both with propeller and generator characteristics. Percentage of SOF (soluble organic fraction) in the PM emission was about 70%. It was also confirmed that measuring the output horsepower accurately on board was as important as measuring the accurate PM emission because PM data should be evaluated as g/kWh same as the data on the test bench.
(2) As a result of the examination on the measuring procedure using the high-speed test engine, the minimum dilution ratio necessary to get the accurate data was verified.
Key words: PM Emission, During Voyage, Dilution Tunnel, SOF, Accurate Measurement
It is quite probable that not only NOx but also PM (particulate matters) emission from ships pollute the coastal environment. Though some studies using marine diesel engines on the test benches were carried out for the environmental protection -, there are few experimental data of the PM emission from marine diesel engines during voyage.
At first in this study, measurement of the PM emission was tried using an experimental ship of 2342 gross tons propelled by a 2-cycle marine diesel engine of 2795 kW and a CPP (controllable pitch propeller). A partial-flow dilution tunnel was applied on board for this test.
According to the PM emission data on voyage, the higher the engine load was, the more PM (g/kWh) were emitted both with propeller and generator characteristics. Percentage of SOF (soluble organic fraction) in the PM emission was about 70%. Though the first trial to measure the PM emission on board was almost successful, there were some difficulties not experienced on the test bench. For example, it is necessary to gather the data as fast as possible because the weather conditions are not always so stable.
Next in this study, the procedure with the partial-flow dilution tunnel fit for the measurement on board was examined. For this investigation of measuring procedure, the experimental ship was not availed but a high-speed marine diesel engine set at the laboratory of National Fisheries University was used.
As results of the examination, the minimum dilution ratio and the minimum sampling weight on a filter (filter loading) necessary to get the accurate data were verified. Adopting the best combination of the dilution ratio and the filter loading, time to measure on board can be saved keeping the accuracy of measured data.