METHOD FOR DETERMINING THE RETENTION CAPACITY OF FUEL VAPOR FILTERS

摘要

The invention relates to a method of determining the retention capacity of fuel vapor filters for motor vehicles, wherein a temperature profile of the fuel is recorded on a motor vehicle in a SHED chamber during a temperature cycle. A fuel vapor volumetric flow for a temperature change is calculated from the temperature profile. In a measurement arrangement (1) fuel is evaporated by means of an evaporator (2) and is output by means of a charging pump (9) to a fuel vapor filter (4) disposed in an oven (5). The bleed emissions of the fuel vapor filter (4) are measured at least during the charging.

主权项

1. A method for determining the retention capacity of fuel vapor filters for motor vehicles, comprising the following process steps:
a) Disposing an at least partly fuelled motor vehicle in a heatable test environment, b) Heating and/or cooling the test environment of the motor vehicle from a specified initial temperature to a specified target temperature during a specified time interval, c) Measuring the fuel temperature during the heating and/or cooling and determining and recording a temperature profile, d) Calculating a theoretical volume of hydrocarbon vapor for the temperature change over the entire temperature cycle according to step b) or taking as a basis an empirically determined volume of hydrocarbon vapor for the temperature change over the entire temperature cycle according to step b), e) Evaporating a volume of fuel f) Disposing at least one fuel vapor filter conditioned for test purposes in a heatable container, g) Heating the container to the target temperature from step b) whilst at the same time charging the fuel vapor filter with the calculated volume of hydrocarbon vapor until reaching the volume of hydrocarbon vapor calculated according to step d) or the empirically determined volume of hydrocarbon vapor h) Cooling the container to the initial temperature whilst discharging the fuel vapor filter with a volumetric flow of flushing air, which corresponds to the charging volumetric flow according to step g), i) Determining the hydrocarbon emissions at the outlet of the fuel vapor filter during charging and j) Possibly repeating process steps g) through i).