| Faced with intense energy situation, methanol with their own advantages stands outamong the many alternative fuels, has becoming one of the most promising car fuel.Methanol has an oxygen-containing molecular structure, which has better economy andemissions fuels. In addition, in China, there are abundant raw materials and matureproduction technology to produce methanol. Therefore, methanol is seen as the importantalternative fuels.Exhaust particulates caused great harm to our living environment and health, which hasbeen valued by human. With further research on engine exhaust particles, relevantdepartments have also introduced more stringent regulations to control exhaust particlesfrom the engine. Therefore, the research on engine particulate emissions is meaningful.In this paper, a study on direct injection methanol engine particulate emissioncharacteristics in stable conditions by experiment method was made. And another study onthe influence of aniline on methanol engine particulate emissions by adding differentproportions of aniline was carried on. The conclusions are as followed:Under the experimental conditions, when the excess air ratio(λ) reaches0.9, the totalconcentration of particle was higher. With the excess air ratio increasing, the totalconcentration of particle decreased and accumulation mode particles slightly increased, andcylinder pressure did not change significantly, and the peak heat release rate decreased, withthe time lagging. With the ignition time advancing, the total particle number concentrationincreased, accumulation mode particles and nuclear states particle number concentrationboth increased. The concentration curve of particles surface area, mass concentration andvolume concentration show the accumulation unimodal curve distribution, and the peakparticle diameter is about200nm. With the decrease of injection timing, the total particlenumber concentration showed a downward trend and the number of accumulation modeparticle concentration also decreased slightly. When the injection time is325°CABTDC, cylinder pressure became the maximum value, and heat release rate curve showed adecreasing trend. With speed increasing, the total number concentration of particlesdecreases firstly, and then rise. The peak cylinder pressure has not changed regularly, and theheat release rate has the similar trend cylinder pressure.In the same conditions, two fuels with gasoline and methanol were used to make a study.By contrast, it can be seen that the number concentration of nuclear states particle and thetotal particle number concentrations produced by fueled with methanol were far lower. Ingasoline exhaust particles, the number concentration of nuclear states particle is relativelyhigher. With particle diameter increasing, the number concentration of particle decreased.Methanol exhaust particulate number concentration is relatively stable, the surface areaconcentration had the similar trend to mass concentration.In gasoline exhaust particles, the nuclear particle number concentration is relatively higher.With the increase of particle size, the particle number declined, and the numberconcentration of methanol fuel particle emissions is smooth. The concentration curve ofparticle surface area had the same trend to particle mass concentration.This paper aniline was chosen as fuel additive. According to the volume fraction ratio, thefuel volume raito was made into0%,0.5%,0.75%and1%. With the different value of λ,ignition timing, injection timing, engine speed were compared. The results show as follows:After adding aniline, the total particle number concentration and nuclear modal particlenumber concentration decreased, but the accumulation mode particle number increased. Withthe increase of aniline ratio, there was no obvious change. When the working condition ofengine was changed, there is not regular change about the particulate emissions. Addinganiline can reduce the particle total number, and aniline ratio of0.5%has the best effect. |
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