Energy & Fuels 2006, 20, 2239-2248
2239
Experimental Analysis of Injection Characteristics Using Biodiesel Fuel Breda Kegl* and Alesˇ Hribernik UniVersity of Maribor, Faculty of Mechanical Engineering, SmetanoVa 17, SI-2000 Maribor, SloVenia ReceiVed June 21, 2006. ReVised Manuscript ReceiVed July 14, 2006
This paper deals with injection characteristics using different fuels at different fuel temperatures. The fuels under consideration are neat biodiesel from rapeseed oil and some blends with diesel as well as neat mineral diesel D2. The fuel and fuel temperature influences are investigated experimentally in the mechanically controlled diesel fuel injection M system. At first, attention is focused on the injection characteristics, especially on fuelling, mean injection rate, mean injection pressure, injection timing, injection delay, and injection duration, which influence the most important engine characteristics. Furthermore, the influence of fuel temperature is investigated. On the basis of the measurements of pressure drop through the fuel filter, the minimum fuel temperature for safe engine operation is determined.
Introduction Biodiesel fuel offers a potentially very interesting alternative to mineral diesel regarding harmful emissions in addition to engine wear, cost, and availability.1,2 Many researchers agree that neat biodiesel generally causes a decrease of unburned HC, CO, and particulate matter (PM) emissions with respect to mineral diesel and an increase of NOx emission.3,4 But even the NOx emission can be moderated to some extent under specific circumstances.5-7 Additionally, biodiesel does not contain carcinogens, such as polyaromatic hydrocarbons and nitrous polyaromatic hydrocarbons, and therefore produces pollutants that are less detrimental to human health when burned.7 However, the high viscosity, high molecular weight, low volatility, etc. of biodiesel fuels may in some cases lead to problems such as severe engine deposits, injector cooking, and piston ring sticking. In general, the viscosity of biodiesel increases by reducing the fuel temperatures. Investigations show that the viscosity of biodiesel from rapeseed oil is not so temperature dependent as the biodiesel from waste cooking oil.8,9 Furthermore, the influencing parameters are the chain length, * E-mail:
[email protected]. (1) Dorado, M. P.; Ballesteros, E.; Arnal, J. M.; Gomez, J.; Lopez, F. J. Exhaust emissions from a diesel engine fueled with transesterfified waste olive oil. Fuel 2003, 82, 1311-1315. (2) Senda, J.; Okui, N.; Tsukamoto, T.; Fujimoto, H. On board measurement of engine performance and emissions in diesel Vehicle operated with biodiesel fuel; SAE 2004-01-0083, 2004. (3) Nabi, N.; Akhter, S.; Shahadat, M. Z. Improvement of engine emissions with conventional diesel fuel and diesel-biodiesel blends. Bioresour. Technol. 2006, 97, 372-378. (4) Hribernik, A. The influence of biodiesel fuel on the injection, combustion, emissions and performance of a direct injected diesel engine. J. Mech. Eng. 2006, 52, 3-14. (5) Szybist, J. P.; Boehman, A. L.; Taylor, J. D.; McCormick, R. L. Evaluation of formulation strategies to eliminate the biodiesel NOx effect. Fuel Process. Technol. 2005, 86, 1109-1126. (6) Kegl, B. Experimental investigation of optimal timing of the diesel engine injection pump by using biodiesel fuel. Energy Fuels 2006, 20 (4), 1460-1470. (7) Lin C. Y.; Lin, H. A. Diesel engine performance and emission characteristics of biodiesel characteristics of biodiesel produced by the peroxidation process. Fuel 2006, 85, 298-305. (8) Kerschbaum, S.; Rinke, G. Measurement of the temperature dependent viscosity of biodiesel fuels. Fuel 2004, 83, 287-291.
Table 1. Biodiesel and Diesel Properties fuel kinematic viscosity at 30 °C (mm2/s) surface tension at 30 °C (N/m) lower calorific value (kJ/kg) cetane number
D2 3.34 0.0255 43.800 45-55
B100 5.51 0.028 38.177 >51
Table 2. Specification of Employed Biodiesel biodiesel, Pinus cetane number ester content (% m/m) sulfur content (mg/kg) carbon residue on 10% distillation residue (% m/m) water content (mg/kg) oxidation stability, 110 °C (h) acid value (mg of KOH/g) iodine value (g of I2/100 g) linolenic acid methyl ester (% m/m) methanol content (% m/m)
European standard for biodiesel, EN 14214
>51 96.9 96.5
