Translated Abstract
With the development of automobile industry, the increasing fuel consumption results in fuel shortage and alternative fuel policy. Methanol is a kind of potential alternative fuel for spark ignition (SI) engine, it contains oxygen and its octane number is high, so methanol can decrease the emissions of SI engine. Nowadays, the stringent regulations were adopted to control automobile tail pipe emissions, as is known, the quantities of HC and CO emitted during cold start and warm-up periods contribute approximate 80%, gasoline has had successful solution about this, but methanol/gasoline blends has not. In this study, the intersolubility of methanol/gasoline blends under low temperature was investigated firstly, and then, the cold start performance of a 4G18 engine fueled with methanol/gasoline blends were researched, at last, the preheating methods were used to improve cold start performance and its regulated emissions characteristics. The main works and results are as follows:
1.According to the physical and chemical properties of methanol, the intersolubility of methanol/gasoline blends under the low temperature from 5℃ to -25℃ was investigated, and the cosolvent used in this experiment were iso-propanol,iso-butanol, iso-amylol and MTBE. The results showed that: Iso-amylol was the best cosolvent when the concentration of methanol is more than 85% or less than 5%, the intersolubility of methanol/gasoline blends performanced excellent when the concentration of methanol is less than 20%, the quantities of cosolvent needed for the methanol/gasoline blends increased with the increase of methanol fraction and the decrease in temperature. According to the results, methanol/gasoline blends of M10, M30, M85 were prepared for the cold start experiment, and the blends kept homogeneous, transparent and stable after 48 hours.
2.Under the temperature of 5℃, -7℃, -15℃ and -25℃, pure gasoline, M10, M30 and M85 were used to the PFI engine during cold start and warm-up periods, and the related data were collected and recorded.The results showed that: The value of AFR increased with the increase of methanol fraction, when the temperature was -7℃, the AFR of M85 was 1.6 times of pure gasoline, it is good for the decrease of CO emission during the warm-up stage, the exhausting temperature increased with the increase of methanol fraction, when the temperature was -15℃, the exhausting temperature of M85 was 100℃ higher than puer gasoline, this performance is good for fast light-off of the three-way catalyst the HC and CO emissions were decreased with the addition of methanol, when the temperature was 5℃, the HC emission of M85 was reduced by 40% than gasoline, and the CO emission of M10, M30, M85 reduced to 72.5%, 50%, 25% of gasoline respectively the HC and CO emissions increased with the decrease of temperature, the fluctuation became violent, according to the average emissions of HC and CO, the influence of temperature to the HC and CO emissions became weak with the increase of methanol fraction.
3.According to the analysis, the inlet air and fuel preheating systems were used to resolve the difficulty of low temperature cold start. The results showed that: The dragging time increased with the increase of methanol fraction and the decrease of temperature, the dragging time decreased after inlet air and fuel preheating when the temperature was -25℃, the preheating systems must be used to successfully start the engine fueled with M10 and M30 however, the engine fueled with M85 still couldn’t start when the temperature was -15℃, the HC and CO emissions were sharply decreased, especially in the first 40s, the HC and CO emissions of M85 decreased by 50% and 60% respectively.
Translated Keyword
[Methanol/gasolineLow temperatureIntersolubilityCold startRegulated emissionsPreheat]
Corresponding authors email
