Aldehyde Emissions from an Ethanol-Fuelled Vehicle as Influenced by Engine Geometric Parameters

Experiments were carried out in an ethanol-fuelled vehicle powered by a 1.0 liter engine to measure exhaust aldehyde and other pollutant gases, hydrocarbons, carbon monoxide, oxides of nitrogen and carbon dioxide, as a function of some engine geometric parameters. The varied parameters were intake and exhaust valve timing, compression ratio and spark plug gap. The tests were developed according to a standard test cycle of 5.8 km, simulating a typical urban travel with an already warmed engine. The results showed the that higher compression ratios can simultaneously reduce aldehyde, carbon monoxide and hydrocarbon emissions, while keeping the level of oxides of nitrogen emissions.