Internal combustion engines suffer from high cyclic variations that result in higher emissions,lower efficiency,higher fuel consump-tion and poor drivability.The purpose of this study is to investigate how Argemone me...Internal combustion engines suffer from high cyclic variations that result in higher emissions,lower efficiency,higher fuel consump-tion and poor drivability.The purpose of this study is to investigate how Argemone mexicana biodiesel(AGB)/diesel blended fuels affect the cyclic variability of combustion parameters such as maximum cylinder pressure(Pmax)and indicated mean effective pressure(IMEP)in a four-cylinder turbocharged intercooled common-rail direct injection engine under various engine loading conditions.The chemical and physical properties of AGB produced from A.mexicana oil were measured and compared according to the ASTM D6751 standards.In various volumetric ratios,AGB and diesel fuel were blended as D100,AB10(10%AGB+90%D100),AB20(20%AGB+80%D100)and AB30(30%AGB+70%D100).The IMEP and Pmax time-series data were collected over 200 consecutive cycles at low,partial and high engine loads at a constant engine speed of 2000 rpm.The coefficients of variation(COV)of combustion parameters(Pmax and IMEP)were measured for different AGB/diesel blends and found to be within acceptable limits.The results show that COV_(Pmax) and COV_(IMEP) decrease as the engine load increases.It was observed that at low load,AB10 has the lowest COV(Pmax,IMEP),and at partial and high load,AB20 has the lowest COV(Pmax,IMEP)among all the blends.展开更多
Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses ...Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses that are situated over the Balkan Peninsula during the year. The method for differentiation of climatic zones is cluster analysis. A hierarchical clustering technique–average linkage between groups with Pearson correlation for measurement of intervals was employed in the research. The climate of the Balkan Peninsula is transitional between oceanic and continental and also between subtropical and temperate climates. Several major changes in atmospheric circulation over the Balkan Peninsula have happened over the period 1950–2012. There is a serious increase of the influence of the Azores High in the period January–Marchwhich leads to an increase of SLP and enhances oceanic influence. There is an increase of the influence of the north-west extension of the monsoonal low in the period June–September. This leads to more continental climatebut also to more tropical air masses over the Balkan Peninsula. Accordinglythe extent of subtropical climate widens in northern direction. There is an increase of the influence of the Siberian High in the period October–December. This influence covers central and eastern part of the peninsula in October and Novemberand it reaches western parts in December. Thusthe climate becomes more continental.展开更多
文摘Internal combustion engines suffer from high cyclic variations that result in higher emissions,lower efficiency,higher fuel consump-tion and poor drivability.The purpose of this study is to investigate how Argemone mexicana biodiesel(AGB)/diesel blended fuels affect the cyclic variability of combustion parameters such as maximum cylinder pressure(Pmax)and indicated mean effective pressure(IMEP)in a four-cylinder turbocharged intercooled common-rail direct injection engine under various engine loading conditions.The chemical and physical properties of AGB produced from A.mexicana oil were measured and compared according to the ASTM D6751 standards.In various volumetric ratios,AGB and diesel fuel were blended as D100,AB10(10%AGB+90%D100),AB20(20%AGB+80%D100)and AB30(30%AGB+70%D100).The IMEP and Pmax time-series data were collected over 200 consecutive cycles at low,partial and high engine loads at a constant engine speed of 2000 rpm.The coefficients of variation(COV)of combustion parameters(Pmax and IMEP)were measured for different AGB/diesel blends and found to be within acceptable limits.The results show that COV_(Pmax) and COV_(IMEP) decrease as the engine load increases.It was observed that at low load,AB10 has the lowest COV(Pmax,IMEP),and at partial and high load,AB20 has the lowest COV(Pmax,IMEP)among all the blends.
文摘Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses that are situated over the Balkan Peninsula during the year. The method for differentiation of climatic zones is cluster analysis. A hierarchical clustering technique–average linkage between groups with Pearson correlation for measurement of intervals was employed in the research. The climate of the Balkan Peninsula is transitional between oceanic and continental and also between subtropical and temperate climates. Several major changes in atmospheric circulation over the Balkan Peninsula have happened over the period 1950–2012. There is a serious increase of the influence of the Azores High in the period January–Marchwhich leads to an increase of SLP and enhances oceanic influence. There is an increase of the influence of the north-west extension of the monsoonal low in the period June–September. This leads to more continental climatebut also to more tropical air masses over the Balkan Peninsula. Accordinglythe extent of subtropical climate widens in northern direction. There is an increase of the influence of the Siberian High in the period October–December. This influence covers central and eastern part of the peninsula in October and Novemberand it reaches western parts in December. Thusthe climate becomes more continental.
