Abstract
With regard to global wanning, reduction of carbon dioxide (CO_2) emission is a problem of great urgency. The thermal efficiency of a marine diesel engine is high. Therefore it is difficult to reduce CO_2 emission by improvement of the thermal efficiency. For such a reason, it is realistic to restrain the use of fossil fuel by using bio-fuel (raw vegetable oil, waste cooking oil) as a countermeasure against global warming, hi this paper, we studied on the emission characteristics of the high speed, naturally aspirated, 4 stroke cycle diesel engine using gas oil, marine diesel fuel (MDF), raw rapeseed oil, raw palm oil and waste cooking oil. The followings were found: Emission of CO of bio fuels is higher than that of gas oil or MDF. Smoke of bio fuels is lower than that of gas oil or MDF.
