Impact of Biodiesel Blends and Di-Ethyl-Ether on the Cold Starting Performance of a Compression Ignition Engine

Abstract

Abstract:The use of biodiesel fuel in compression ignition engines has the potential to reduce CO 2 , which can lead to a reduction in global warming and environmental hazards. Biodiesel is an attractive fuel, as it is made from renewable resources. Many studies have been conducted to assess the impact of biodiesel use on engine performances. Most of them were carried out in positive temperature conditions. A major drawback associated with the use of biodiesel, however, is its poor cold flow properties, which have a direct influence on the cold starting performance of the engine. Since diesel engine behavior at negative temperatures is an important quality criterion of the engine's operation, one goal of this paper is to assess the starting performance at´20˝C of a common automotive compression ignition engine, fueled with different blends of fossil diesel fuel and biodiesel. Results showed that increasing the biodiesel blend ratio generated a great deterioration in engine startability. Another goal of this study was to determine the biodiesel blend ratio limit at which the engine would not start at´20˝C and, subsequently, to investigate the impact of Di-Ethyl-Ether (DEE) injection into the intake duct on the engine's startability, which was found to be recovered.

Review on the Use of Diesel–Biodiesel–Alcohol Blends in Compression Ignition Engines

“…Thus, when performing a cold start at low ambient temperatures, the resulting higher viscosity of the fuel causes poorer fuel atomization and vaporization, larger droplets, and greater in-cylinder penetration of the fuel spray. As shown in [22], a high viscosity may also reduce fuel flow rates, resulting in inadequate fueling; another aspect reported in the same paper is that a very high viscosity may also result in pump distortion. The final effects may be evident as a bad combustion, higher emissions, and increased oil dilution.…”

“…Fuel density is also affected by the temperature: it increases as the temperature decreases; as before, when performing a cold starting at low ambient temperatures, the resulting higher density means that the same injected fuel volume generates a higher mass of the fuel injected, which will affect the air-fuel ratio and the energy content inside the cylinder, as explained in [22].…”

“…Its use does not require considerable modifications in the engine, when small amounts are used. Most probably, as discussed in [9,13,22,23], biodiesel blends will consist of no more than 20 per cent of the biofuel in petroleum diesel fuel, because higher ratios of biodiesel require technical modifications in the fueling system of the engine (see Section 4).…”

“…Besides the superiority of biodiesel, there are obviously disadvantages, as compared to diesel: it suffers from cold weather starting problems [22,24], it is corrosive if exposed to brass and copper, it produces deposits in injector, on the piston head, it causes excessive engine wear, and it has higher production costs [23].…”

Proposal of a Predictive Mixed Experimental- Numerical Approach for Assessing the Performance of Farm Tractor Engines Fuelled with Diesel- Biodiesel-Bioethanol Blends

“…Since the fuel viscosity increases as the ambient temperature decreases, when performing a cold start at low ambient temperatures the resulting higher viscosity of the fuel causes poorer fuel atomization and vaporization, larger droplets, and a greater in-cylinder penetration of the fuel spray [4,[15][16][17]. High viscosity may also reduce fuel flow rates, thus affecting the optimal functioning of auxiliary equipment such as the fuel feed pump [18,19]. The fuel density increases as temperature decreases.…”