The dwindling conventional fuel resources and the environmental issues associated with these fuels are of major concern to the world. It has been the ultimate goal to find sustainable fuel resources for transportation. The transportation sector, ultimately, would have to be supported by a mix of different energy sources. Biodiesel is one of the most important bio-fuels, which can partially replace conventional diesel fuel.

Biodiesel derived from different sources of vegetable oils such as soybean oil, palm oil, sunflower oil and rapeseed oil etc. are used in different parts of the world. However, for a sustainable solution, biodiesel has to be produced from non-edible oils. In India, the different oil seeds identified as having potential for biodiesel production are jatropha carcus, karanjia and pongamia pinnata etc. Plants like jatropha curcas can grow in wasteland unsuitable for crop cultivation. In India, over 100 Mha are classified as degraded land [1] and this can be utilized to grow such plants for biodiesel production.

Biodiesel has advantages both in terms of pollutant emissions and greenhouse gas emissions (GHGs). A reduction in full fuel-cycle GHGs by 41–51% are reported for biodiesel [2]. Reductions in pollutant emissions such as PM, CO and HC and slight increase in NOx emissions are reported by most of the researchers. A comprehensive analysis of biodiesel impacts on exhaust emissions done by EPA, USA estimated that, for soybean-based B20, the percent change in emissions are: +2.0% for NOx, -10.1% for PM, -21.1% for HC and -11.0% for CO [3]. A study by P. K. Srivastava and M. Verma found that methyl ester of karanjia increased HC, CO and NO emissions [4]. T.D. Durbin et al. also reported increase in HC and CO emissions for various biodiesel blends such as B20 derived from soybean oil [5]. A literature survey by M. Lapuerta et al. also reported both decrease and increase in NOx, PM and HC emissions [6]. However, the majority of the papers surveyed by them showed increase in NOx and decrease in PM and HC.

The results of the different studies discussed indicate variation in emissions with the use of biodiesel. In India, biodiesel from jatropha carcus and pongamia pinnata are widely investigated. However, most of the studies are done on jatropha carcus derived methyl ester. The present study is done on jatropha carcus derived ethyl ester (JEE). In the present study, the engine performance and emission characteristics of an automotive diesel engine fuelled with diesel and JEE blends are investigated. Brake horse power (bhp), brake specific fuel consumption (bsfc), mass emissions of nitrogen oxide (NOx), carbon monoxide (CO) and unburnt hydrocarbon (HC) were investigated and discussed. The fuel properties of the biodiesel were also tested as per ASTM standards.

The biodiesel used in the study was a Jatropha Carcus derived ethyl ester (JEE) produced at IIP, Dehradun. The properties of the biodiesel were within the standard limits. Commercial diesel (HSD) was used as the reference fuel.

The mass emissions and performance of the engine were done for diesel and JEE blends (10–20% JEE in diesel). The data on performance and mass emissions of diesel was used as the base data to compare the performance and mass emissions of the JEE blends. Analysis of physico-chemical properties of diesel and JEE were carried out. The density, kinematic viscosity, pour point, cloud point, flash point, cetane number, total sulfur and copper strip erosion, were analyzed as per the methods given in ASTM D-4052, ASTM D-445, IP-15, IP-219, IP-170, ASTM D-613, ASTM-D5453 and IP-154, respectively. The properties of the test fuels are given in Table 1.

The engine used in the study was an automotive diesel engine. The engine specifications are shown in Table 2. No modification of the engine was done. The engine was coupled to a Dynalec Eddy Current Dynamometer. The torque was measured by load cell torque measurement system. The power absorbed by the machine is measured by relating the shaft speed measured through a magnetic pulse pick-up transducer which operates in conjunction with 60 toothed wheel, fixed to the rotating dynamometer shaft and the measured restraining torque.

Pierburg Exhaust Gas Analyser was used to measure the concentrations of carbon monoxide, nitrogen oxides and hydrocarbons. AVL smart sampler was used for the measurement of particulates for diesel exhaust. The system works on principle of CVS (constant volume sampling). The smart sampler consists of moveable dilution tunnel with filter holders. The engine intake air was measured using a Meriam Laminar flow element (LFE). An AVL dynamic fuel-meter was used to measure fuel consumption. The system works on gravimetric measuring principle, and has unique measuring range of 0 to 150 kg/h with measuring accuracy of 0.12%.

The 13-mode cycle tests as per ECE R49 for particulates and gaseous emissions measurement were carried out on the engine mounted on the dynamometer test-bed. WOT performance at different speeds of the engine related to the brake specific fuel consumption (bsfc) and brake horse power (bhp) characteristics of the diesel and the biodiesel were also done. The particulates were collected on the filter paper during each of the 13 modes as per ECE R49 cycle procedure.

Jatropha carcus derived ethyl ester was investigated for performance and emission characteristics in an automotive diesel engine. The fuel properties of the biodiesel were within the standard limits. The mass emissions of NOx showed 4–9% increase with 10–20% JEE blends. PM emission for JEE-20 was almost same as that of diesel. There was no significant change in brake horse power (bhp) of both blends when compared to that of diesel.

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