Currently, regulations on vehicle evaporative emissions only focus on the sum of Total Hydrocarbons (THC) without taking into account either the detailed hydrocarbon composition nor other chemicals besides hydrocarbons emitted from gasoline evaporation. As a consequence, this composition, also known as speciation, is not always noted and is even more unknown when biofuels such as ethanol are introduced in the market. Furthermore, these regulations do not differentiate the source of these emissions in the vehicle.
The programme described in this paper is designed to investigate the influence of the addition of ethanol to gasoline on evaporative emissions. It has tried to go one step ahead of these directives obtaining more detailed characterization of these evaporative emissions.
The programme has enabled a list of compounds (methanol, ethanol, aldehydes, ketones and hydrocarbons) to be determined in evaporative emissions among different ethanol-gasoline fuels (E0, E5-S, E10 and E85), applied to Euro 4 and Flexifuel vehicles by three chromatographic methods based on California Air Resources Board (CARB). Additionally, permeation from evaporation emissions has been determined separately.
This document provides valuable information about the speciation of evaporative emissions and several conclusions have been drawn.