ISO 21755-2-2020 pdf free.Motorcycles — Measurement methodfor evaporative emissions — Permeation test procedure.
This document specifies a basic measurement method by using a permeation test procedure forevaporative emissions from motorcycles. lIt is applicable to motorcycles equipped with a fuel tank tostore liquid high volatile fuel and with a spark ignition engine (four-stroke engine, two-stroke engine orrotary piston engine).There are no normative references in this document.For the purposes of this document, the following terms and definitions apply.
Measure permeation emissions by weighing a sealed fuel tank before and after a temperature-controlled soak according to the following flow charts (see Figure 1).The test fuel shall be selected in accordance with agreement among the parties involved or themanufacturer’s requirements and the specifications of test fuel shall be reported.An example of therecord form is given in B.2.
Preconditioning fuel soak for the fuel tank permeation test.To precondition the fuel tank in the fuel tank permeation test, the following five steps shall be followed:The tank shall be filled with reference fuel specified in 4.2 and sealed. The filled tank shall besoaked at an ambient temperature of 301,2K 5,0 K for 20 weeks or at 316,2K 5,0 K for 10 weeks.The fuel tank’s internal surface area shall be determined in square metres accurate to at leastthree significant figures. The manufacturer may use less accurate estimates of the surface area if it isensured that the surface area will not be overestimated.
The fuel tank shall be sealed using fuel caps and other fittings (excluding petcocks) that can beused to seal openings in a production fuel tank. ln cases where openings are not normally sealed on thefuel tank (such as hose-connection fittings and vents in fuel caps), these openings may be sealed usingnon-permeable fittings such as metal or fluoropolymer plugs.To run the test, the following steps shall be taken for a tank preconditioned as specified in 4.3.
Weigh the sealed fuel tank and record the weight in milligrams. This measurement shall be takenwithin 8 h of filling of the tank with test fuel.
The tank shall be placed in a ventilated, temperature-controlled room or enclosure.The test room or enclosure shall be closed and sealed and the test time shall be recorded.ISO 21755 pdf download.