Search Results

The aim of this research is to experimentally investigate the effects of combustion parameters [ignition timings, injection timings, excess air ratio (λ)] and lubricating oil on particulate matter (PM) emissions from a 2.0 L turbo-charged gasoline direct injection (T-GDI) engine fueled with gasoline (octane number = 97), methanol/gasoline blends and pure methanol. The results of this paper show that the PM number concentration mostly presents a typical bimodal distribution in figures. The particle number concentration mainly concentrates in the nucleation mode. With the increase of methanol volume fraction in the blended fuel, the PM emissions decrease significantly. Furthermore, there are few particles when the engine fueled with pure methanol. As advancing ignition timing, the total PM number rises by over about 200%. Under the pre-ignition condition, the higher in-cylinder temperature may also accelerate the formation of the nucleation mode particles.

This research presents an experimental study of the laminar burning combustion and emission characteristics of premixed methane -dissociated methanol-air mixtures in a constant volume combustion chamber. All experiments were conducted at 3 bar initial pressure and 373K initial temperature. The dissociated methanol fractions were from 20% to 80% with 20% intervals, and the equivalence ratio varied from 0.6 to 1.8 with 0.2 intervals. The images of flame propagation were visualized by using a schlieren system. The combustion pressure data were measured and exhaust emissions were sampled with a portable exhaust gas analyzer. The results show that the unstretched laminar burning velocities increased significantly with dissociated methanol enrichment. The Markstein length decreased with increasing dissociated methanol fraction and decreasing equivalence ratio.