Research On Particulate Matter Emission Characteristics From A GDI Vehicle

In recent years, climate change, energy security and other issues have becomeincreasingly prominent. Now energy conservation and emission reduction have becomeimportant tasks of the government. As one of the major energy consumers and polluter,vehicles need some appropriate technologies to reduce energy consumption and emissions.The gasoline direct injection vehicles have good performance, energy economy, and lowerCO2emissions, its development potential is great in traditional automobile industry. It hasbeen becoming one of the hottest topics technology, many car manufacturers have alsointroduced the corresponding models to meet market requirements. However, direct injectiongasoline engines produces lots of tiny particles which is harmful for human health in theprocess of driving, and some emissions regulations have begun put limits on the mass ofparticulate emissions from gasoline vehicles. To maintain human health and meet theincreasingly stringent emissions regulations, it’s necessary to study on particulate matteremission characteristics from direct injection gasoline sedans.In this sturdy, the particulate matter emissions of a gasoline direct injection sedan werestudied over the FTP and NEDC on a chassis dynamometer. Our purpose is to study theeffect of vehicle driving conditions on particulate emissions characteristics. Theexperimental results showed that:1) During the FTP and NEDC driving cycle, engine load isin the middle and low load conditions, and engine is at small and medium speed. In theaspect of distribution range of engine working conditions, NEDC is broader than FTP, but itsengine working conditions are concentrated in a smaller region. Its main feature is in narrowrange of engine speed.2) Particle size distribution of the different engine working conditionsare different. Nucleation particles and accumulation particles codetermines the distributionof particle number concentration, particle surface area concentration and particle massconcentration. But mainly the particle diameter where particle mass concentration peakappeared is greater than the particle diameter where particle surface area concentration peak appeared. The distribution of particle mass concentrations are more susceptible toaccumulation particles.3) When particulate emission test were conducted under differentdriving conditions, particle distribution vary with driving conditions. Acceleration results inthe rise of particle number concentration, and deceleration decrease the particle numberconcentration. In the idle conditions, particle number concentration is relatively stable.During city driving cycle, both nucleation particles and accumulation particles fluctuatebasically in the same order of magnitude, but in the acceleration conditions particle numberconcentration of nucleation particles increases higher than accumulation particles’. In theaspect of particle surface area, the concentration of the accumulation particles is higher thanthe concentration of nucleation particles about an order of magnitude. The particle massconcentration of the accumulation particles has an obvious advantage over nucleationparticles’, the accumulation particles concentration distribution is similar to the total particlemass concentration distribution.4) FTP has more varying acceleration conditions, andparticle number concentration varies obviously with the change of the speed. Particlenumber concentration peaks of the start-up phase is higher than the transition phase’s,significant particle number concentration peak usually occurs in hard acceleration phase.5)The vehicle transfer from other conditions to idle condition, particle size distribution willcontinue to change over time, and then gradually stabilized. Idling condition particle numberconcentration showed a bimodal distribution. Particle surface area concentration distributionand mass concentration distributions are unimodal distribution with peaks in accumulationparticles section.