Rationale of Dedicated Low Emitting CNG Cars

A 2.0 liter displacement gasoline fueled car, with closed-loop control and 3-way catalyst, was adapted to operate on CNG (Compressed Natural Gas). A system allowing the detection and measurement of aldehydes, ketones, polycyclic aromatic hydrocarbons (PAH) and speciated organic materials was set up. Running on different fuels, such as CNG, gasoline and gasoline/oxygenates blends, tests were carried out according to US (FTP '75) and European (ECE+EUDC) procedures with and without the original 3-way catalytic converter. Apart from the absence of evaporative emissions because of the required closed delivery system, test results pointed out that CNG use yields substantial air toxics benefits in terms of regulated and, above all, unregulated emissions.