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The present paper investigates about the production of biodiesel from neat Mahua oil via base catalyzed transesterification and mixing of the biodiesel with a suitable additive (Dimethyl carbonate) in varying volume proportions in order to prepare a number of test fuels for engine application. The prepared test fuels are used in single cylinder water cooled diesel engine at various load conditions to evaluate the performance and emission parameters of the engine. The results of investigation show increase in brake power and brake thermal efficiency with load for all prepared test fuels. It is also noticed that brake thermal efficiency increases with the percentage of additive in all the test fuels. The brake specific fuel consumption decreases with increase in additive percentage. Exhaust gas temperature increases almost linearly with load for all test fuels and decreases with increase in additive percentage. It is also seen from the results that both CO and HC emissions tend to decrease with increase in additive percent age in biodiesel. The smoke and NOx emissions also decrease with increase in additive percentage in the biodiesel fuel. During the course of this experimental investigation it was found that the overall performance and emission characteristics of the engine was satisfactory with all the test fuels and improved with repeated experiments. All the test results significantly improved with increase in the additive percentage in biodiesel. Therefore the present paper provides a strong platform to continue further investigation on using biodiesel fuel in a diesel engine with variety of fuel additives under varying engine operating parameters.

The present experimental study demonstrates the performance and emission characteristics of a single cylinder dual fuel diesel engine with producer gas as the primary fuel and diesel, preheated Jatropha oil and Jatropha oil methyl ester as injected fuels. In order to reduce the viscosity of Jatropha oil, a shell and tube type heat exchanger was designed and fabricated for preheating Jatropha oil using engine exhaust gas. The performance parameters, such as brake specific fuel consumption, brake thermal efficiency and exhaust gas temperature, have shown improved results with baseline diesel and producer gas, whereas the above parameters are very close to other test fuels under different loading conditions. All the emission parameters are found to be on the higher side for preheated oil-compared to diesel-producer gas dual fuel operation at all load conditions. With Jatropha oil methyl ester-producer gas dual fuel operation, however, emission parameters such as CO 2 , smoke and NOx are higher compared to diesel-producer gas operation. The smoke emission for preheated Jatropha oil-producer gas dual fuel operation is approximately 60% higher than that of diesel-producer gas operation at full load. From the present experimental investigation it may be concluded that alternative fuel combinations such as preheated Jatropha oil-producer gas and Jatropha oil methyl ester-producer gas can successfully replace diesel as the major fuel in diesel engines with little modification. The present paper also recommends further investigation to improve fuel properties and in-cylinder combustion phenomena of preheated Jatropha oil and its methyl ester before use in a diesel engine.

In this study, 18 soapnut biodiesel-diesel blends along with soapnut oil as an additive in some blends were prepared and used in a diesel engine to investigate the effect of oxygen content in the fuel blends on engine performance and emission characteristics. Considering the large variations in the oxygen content of these fuel blends, the obtained results were demonstrated based on varying fuel oxygen content. Findings showed that the best engine performance was achieved with a fuel oxygen content in the range of 1.8%-3.0%, whereas the best engine emissions were obtained with a fuel oxygen content in the range of 0.71%-2.37%. Hence, considering both engine performance and emissions, the optimal zone of fuel oxygen content was found to be in the range of 1.80%-2.37%. Thus, it can be concluded that biodiesel blended fuels having an oxygen content in the aforesaid range can be successfully used in diesel engines with comparable engine performance and emissions to those using diesel fuel. Nevertheless, further research is required to reduce the fuel oxygen content to this optimal range if the blends consist of higher biofuel components. Besides that, the use of suitable additives in the biodiesel blended fuels may be a viable option to achieve the said purpose, which needs further research.

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In the present work,18 numbers of soapnut biodiesel-diesel blends along with soapnut oil as additive in some cases were used in a compression ignition engine forcomparative assessment of the effect of fuel blends on the engine performance. Considering the large variations in oxygen content of the fuel blends it was opted as the basis for the study. Results showed that the best engine performance is achieved with oxygen content in the fuel blends in the range 1.8-3.0%. The emission results showed that the best engine emission is obtained for oxygen content in the fuel blends in the range 0.71-2.37%. Considering engine performance and emissions, the critical zone of oxygen content was found to be in the range 1.8-2.37%. The fuel blends having oxygen content within this critical zone, i.e. fuel blend nos. 8-13 were found to be best with higher engine performance and lower exhaust emissions.

Let N n (w) be the number of real roots of the random algebraic equation ^2l =o a v i v (w)x 1 ' = 0 . where the £ v {w) 's are independent, identically distributed random variables belonging to the domain of attraction of the normal law with mean zero and /"{) ^ 0} > 0 ; also the a v 's are nonzero real numbers such that {kjt n )= O(logn) where k n = m a x 0 < j / < n \a v \ and t n = m i n 0 < I / < n \a v \. It is shown that for any sequence of positive constants (e n , n > 0) satisfying e n -» 0 and e n log n -• oo there is a positive constant fi so that e n \ e^ logn,,)" 1 for all n 0 sufficiently large.1991 Mathematics subject classification (Amer. Math. Soc): 60 B 99.

The present work studies the influence of di-tertiary-butyl peroxide (DTBP) as a cetane-improving additive to karanja methyl ester (KME) on the combustion, performance and emission characteristics of a diesel engine. KME produced by base catalyzed transesterification of non-edible karanja oil was blended with DTBP in different volume proportions to result KMED1 (99% KME + 1% DTBP), KMED2 (98% KME + 2% DTBP), KMED3 (97% KME + 3% DTBP) and KMED5 (95% KME + 5% DTBP) fuel blends. With increase in DTBP content, viscosity was reduced, whereas the cold flow properties, cetane index and calorific value were enhanced. Engine test results exhibited improvement in brake thermal efficiency and brake specific energy consumption for all blends compared to neat KME. Combustion analysis showed improved combustion with rise in DTBP content in the blends. The CO, HC and NOx emissions with KME-DTBP blends were less compared to neat KME and the same significantly reduced with rise in DTBP percentage in the blends. This shows improved combustion due to more oxygen availability and improvement in fuel properties with addition of DTBP to KME. However, the NOx emissions were marginally higher with KME-DTBP blends compared to neat KME and diesel that may be further studied.