S. Saravanan

Feasibility study of crude rice bran oil as a diesel substitute in a DI-CI engine without modifications

Oil extracted from the inner husk of rice, termed rice bran oil (RBO), promises to be a low-cost, renewable substitute for petroleum-derived diesel as a compression ignition (CI) engine fuel. While rice is a major crop in India, RBO is underutilized. This research work concentrates on the study of the prospect of using unrefined RBO as a diesel engine fuel without any modifications. Like other vegetable oils, crude RBO faces the problem of high viscosity and hence blending RBO with diesel is attempted in this work. Tests were conducted in a naturally aspirated direct injection (DI) four-stroke 4.4 kW stationary diesel engine with pure RBO and blends of RBO with diesel. It is observed that specific energy consumption (SEC) of RBO is higher than that of all the fuels at all loads and for 25% RBO, it is very close to that of diesel. As an oxygenated fuel, RBO reduces emission of pollutants like CO and unburnt hydrocarbon (UBHC) by supplying additional oxygen from the fuel. At no-load condition the delay period for RBO and its blends were slightly higher than for diesel. As the load increased the delay periods were shorter than for diesel. The maximum heat release rates of RBO and its blends were lower than that of diesel. The peak pressures for RBO and its blends were slightly higher and occurred earlier than that of diesel. In general blended fuels result in lower viscosity, better combustion and lesser emission than RBO and 25% RBO shows better results than RBO and other blends of RBO.

The comparative analysis of diesel engine combustion and emission parameters fuelled with palm oil methyl esters and its diesel blends

In this work, the combustion and emission characteristics of a direct injection compression ignition engine fuelled with diesel-Palm Oil Methyl Ester (POME) blends are investigated. This study shows that the ignition delay decreases with increase in the POME addition. The maximum rate of pressure rise and maximum rate of heat release decreases with increase in POME addition at all loads. As the percentage of POME in the blend increases, the crank angle at which the maximum rate of heat release takes place advances. The brake thermal efficiency decreases with increase in POME addition. The unburned hydrocarbon, carbon monoxide and soot intensity decreases, while nitrogen oxides (NOx) increase with increase in POME addition. [Received: April 4, 2008; Accepted: November 24, 2008]

Investigation on combustion characteristics of crude rice bran oil methyl ester blend as a heavy duty automotive engine fuel

In the present work, an attempt was made to test the suitability of crude rice bran oil methyl ester (CRBME) blend as a heavy duty automotive engine fuel. A four stroke, six cylinder direct injection 117.6 kW turbo-charged compression ignition (CI) engine was used for the work. The operation of the engine with CRBME blend showed that the peak pressure increased with lower maximum rate of pressure rise and maximum heat release rate with shorter delay period. Burning rate of the CRBME blend was slower and required a higher crank angle to complete the combustion cycle when compared to diesel. The brake thermal efficiency of the CRBME blend was lower than that of diesel at all speeds except at 2300rpm. As the measured combustion and performance parameters for CRBME blend differs only by a smaller magnitude when compared with diesel, this investigation ensures the suitability of the CRBME blend as fuel for heavy duty automotive engine without any design modifications

Effect of blending crude rice bran oil methyl ester with diesel on properties as CI engine fuel

AbstractIn this study, an attempt was made to investigate the effect of blending a biodiesel derived from high free fatty acid crude rice bran oil (CRBO) with diesel on the properties as a fuel for compression ignition (CI) engine. Biodiesel [crude rice bran oil methyl ester (CRBME)] blend was prepared by mixing 20% CRBME with 80% diesel on a volume basis. As a result of blending CRBME, the flash point and viscosity of diesel increased by 14 and 3·4% respectively and calorific value decreased by 2%. The distillation curve of the CRBME blend was almost similar as that of diesel and an end point temperature of 337°C was obtained during the distillation of CRBME blend. Blending CRBME with diesel increases the specific gravity marginally and its cetane number increased by 2·3%. From this investigation, it was inferred that the properties of CRBME blend were comparable with that of diesel and it can be utilised as a CI engine fuel. As a renewable fuel its role as a partial substitution of diesel fuel can be vital.

Application of Taguchi’s orthogonal array in reducing the NO x emission of a stationary diesel engine

The main objective of this investigation is to reduce the NO x emission of a stationary diesel engine with less sacrifice on smoke intensity and brake thermal efficiency (BTE). Fuel injection timing, percentage of EGR and fuel injection pressure are chosen as factors influencing the objective. Three levels were chosen in each factor and design of experiments method was employed to design the experiments. Taguchi’s L9 orthogonal array was used to conduct the engine tests with different levels of the chosen factors. Test results were analysed by analysis of variance (ANOVA) method and ANOVA table was formed for each response variable. From the ANOVA table the most influencing factor and also the significance of each factor affecting the NO x emission, smoke intensity and BTE was found out. Response graph was drawn for each response variable to determine the optimum combination of the factor levels. This optimum combination was confirmed experimentally.

Combustion analysis of a direct injection diesel engine when fuelled with sunflower methyl ester and its diesel blends

Uncertainty in the availability of petroleum-based fuels in the near future and stringent pollution norms have triggered a search for renewable and clean-burning fuels. The use of vegetable oil as an alternative fuel has for long been in the pipeline, but its direct use has been limited because of its higher viscosity. In this work, sunflower oil was taken as feedstock and the feasibility of sunflower oil methyl ester (SFME) as an alternative fuel for diesel engines was investigated. Tests were conducted in a 4.4 kW, single cylinder; naturally aspirated direct injection diesel engine. It was observed that the premixed combustion phase of SFME and its blends were less intense compared with diesel oil. In addition, it was observed that SFME and its blends had slightly lower thermal efficiency and lower tailpipe emissions than diesel oil.

Effect of EGR on performance and emission characteristics of diesel engine at advanced injection timing

This work attempts to reduce the smoke density of diesel engine by advancing the fuel injection timing and also the NOx emission of the engine by introducing EGR at the advanced injection timing. A single cylinder 4.4 kW air cooled, naturally aspirated, stationary diesel engine was utilised for the investigation. Engine tests were conducted at different loads at standard injection timing and advanced injection timing with and without EGR and performance and emission parameters were measured. It was observed that the smoke density was decreased by 33% at advanced injection timing with 20% increase in NOx emission. As a result of EGR, NOx emission was decreased by 63% with marginal increase in smoke density. The increase in smoke density resulted from EGR is lower than the smoke density of the engine at standard injection timing. Advanced injection timing with EGR increases the maximum heat releases rate of the engine.

Engine Analysis of Single Cylinder DI Diesel Engine Fuelled With Sunflower Oil, Sunflower Oil Methyl Ester and Its Blends

In the present work, the combustion, performance and emission characteristics of sunflower oil, sunflower methyl ester and its blends were studied and compared with diesel by employing them as fuel in a single cylinder, direct injection, 4.4 KW, air cooled diesel engine. Emission measurements were carried out using five-gas exhaust gas analyzer and smoke meter. The performance characteristics of Sunflower oil, Sunflower methyl ester and its blends were comparable with those of diesel. The components of exhaust such as HC, CO, NOx and soot concentration of the fuels were measured and presented as a function of load and it was observed that the blends had similar performance and emission characteristics as those of diesel. NOx emissions of sunflower oil methyl ester were slightly higher than that of diesel but that of sunflower oil was slightly lower than that of diesel. With respect to the combustion characteristics it was found that the biofuels have lower ignition delay than diesel. The heat release rate was very high for diesel than for the biofuel.Copyright

Multi response optimisation in emission control of CI engine fuelled with crude rice bran oil blend

In the present work, high free fatty acid (FFA) crude rice bran oil (CRBO) blend was tested in a stationary CI engine and investigation was focused to reduce NOx emission than diesel with lesser smoke density. Combustion process was modified by varying the factors namely fuel injection timing, percentage EGR and fuel injection pressure in a combination suggested by Taguchi’s L9 orthogonal array. Three levels were chosen in each factor and NOx emission, smoke density and brake thermal efficiency were taken as the response variables. Multi response signal-to-noise (MRSN) ratio was calculated for the response variables and the optimum combination level of factors was obtained simultaneously using Taguchi’s parametric design. Obtained optimum combination level was confirmed experimentally and significant improvement was observed in the response variables.

Optimization of a Stationary Diesel Engine Fuelled With Crude Rice Bran Oil Methyl Ester Using the Taguchi Method

In the present work an attempt was made to reduce the NOx emission of crude rice bran oil methyl ester (CRBOME) with a marginal increase in smoke density and decrease in brake thermal efficiency in a stationary CI engine. Three factors namely fuel injection timing, quantity of exhaust gases recycled and fuel injection pressure were chosen. Experiments were designed by employing design of experiments method and tests were conducted with combination of factors as per Taguchi’s L9 orthogonal array. Percentage contribution of each factor and the most influencing factor in controlling the response variables (NOx emission, smoke density and brake thermal efficiency) were obtained through ANOVA. Multi-response signal-to-noise (MRSN) ratio was calculated and the optimum combination level of factors was obtained simultaneously using Taguchi’s parametric design. Among the three, the most influencing factor for the chosen objective was found out by analyzing the MRSN ratio through ANOVA. The optimum combination obtained shows a lower NOx emission with less influence on smoke density and brake thermal efficiency.