ETHANOL BLEND FUEL PERFORMANCE ON EVAPORATIVE EMISSION OF MOTORCYCLE IN THAILAND

The ethanol blended fuel performance evaluation are performed on motorcycles in Thailand. The evaporative emission from four models of four-stroke motorcycle fuel with E0 , E10 and E20 are tested in this study. The are totally 8 motorcycles; two motorcycles from each selected models, are use for performing the tests. The evaporative emission and tailpipe emission are measured in difference legislation. The emissions from MC model A and C (fuel injection) are measured according to TIS 2350- 2551 (equivalent to 97/24/EC , Euro 3). MC model B and D (carburetor) are tested according to TIS 2130- 2545 (combination of 97/24/EC & JASO T 902-95, Taiwan). The evaporative emission, hydrocarbon emitted from SHED (Sealed Housing Evaporative Determination) chamber are quantified. Evaporative emission testing consists of a hot soak losses (HSL) test and tank breathing losses (TBL) test. Only MC model A can be used ethanol blended gasoline up to 20%. The three test fuels; E0, E10 and E20 were tested with all vehicles operating both of tailpipe emission and evaporative emission. E0 (RON 91) is use as a baseline fuel for this study.
The total evaporative emission, (HSL + TBL) results from all models of motorcycle fuel with E10, E20 in comparison to E0 show the same tendency. It was found that baseline fuel (E0,RON91) show the highest evaporative emission. Considering the fuel properties RVP and T50 which are effect to the variation of evaporative emission, E0 give the highest RVP and T50 compared to E10 and E20. With this reason the evaporative emission from E0 is highest one. The evaporative emission from E10 and E20 are not difference. TBL is the majority of total evaporative emission from motorcycle cause by the permeation of HCs through the rubber seal of the fuel tank. E0 show the highest of TBL for all MC model.
Fuel distribution to the engine system is also one of the factors that effect to evaporative emission. The test result show MC model B and D, carburetor system, show the higher evaporative emission than MC model A and C which are fuel injection system and still in the range of 2 – 6 g/test which may meet TIS 2130-2545 legislation. However MC model A and C is meet Euro 3 limit (less than 2 g/test) for all kind of test fuel (E0, E10 and E20). The carburetor system is more influence to HSL contribution than injection system.