Effect of Ethanol Port-Fuel-Injector Position on Dual-Fuel Combustion in an Automotive-Size Diesel Engine

Abstract

In contrast to the conventional approach of using ethanol in spark-ignition engines, this study demonstrates the potential of ethanol utilization in diesel engines using dual-fuel combustion, where ethanol is injected into the intake manifold and diesel is directly injected into the engine cylinder. The main focus is the effect of the ethanol port-fuel-injector (PFI) position on dual-fuel combustion and engine-out emissions. In this study, Mie-scattering spray imaging and engine tests were performed in an optical spray chamber simulating the intake manifold condition and a single-cylinder, automotive-size diesel engine, respectively. Two PFI positions are selected: one close to the hot intake valves, so that the sprays impinged upon the hot valve surface (position A), and the other further upstream of the intake valves, allowing increased residence time for interactions between ethanol droplets and intake airflow (position B). From ethanol spray images, it is suggested that the droplet size is smaller for PFI position B because of enhanced droplet−airflow interaction. However, the measured engine-out emissions show lower unburnt hydrocarbon and carbon monoxide emissions for PFI position A. This is argued to be due to reduced wall wetting because the surface boiling of ethanol droplets occurred on the hot valve seat and intake port wall. It is also found that the effect of the PFI position on global parameters, such as in-cylinder pressure, apparent heat release rate, and mean effective pressure, is much less significant than the effect of ethanol energy fraction. The maximum ethanol fraction is limited by misfiring associated with over-retarded combustion phasing. This limit is found to be higher for PFI position A because the wall-wetting is less problematic, consistent with the carbon monoxide and unburnt hydrocarbon emissions trend.

Influence of fuel temperature on atomization parameters in a pressure-swirl atomizer from a port fuel injector by Shadowgraphy technique

“…They found results for injection duration as function of flow rate, number of droplets and mean drop diameter for transient and quasi-steady states and cross-flow effects on droplets. A different approach was made by Padala et al [14] when analyzing ethanol utilization in diesel engines using dualfuel combustion. Ethanol was used as port fuel injection and diesel as direct injection and they demonstrated that the position of ethanol PFI influences the combustion process and emissions.…”

Emission analysis of a Diesel Engine Operating in Diesel–Ethanol Dual-Fuel mode

“…89 Egúsquiza et al [16] also tested a single cylinder engine, with 90 1075 cm 3 of displacement, running in Dual-Fuel mode, either Die-91 sel-Ethanol or Diesel-CNG. Padala et al [30] used a smaller cylin-92 der (497.8 cm 3 ) in Dual-Fuel mode using standard diesel for the 93 pilot injection and ethanol as secondary fuel. These earlier studies 94 had involved the use of small sized cylinder.…”

“…Shi et al (2005) Emission reduction potential of using ethanol-biodiesel-diesel fuel blend on a heavy-duty diesel engine NOx " CO = THC ;Aldehydes " Lü et al(2004) Effect of cetane number improver on heat rate and emissions of high speed diesel engine fueled with ethanol-diesel blend fuel NOx ; CO " THC " Aldehydes N/A Padala et al[30] Effectof Ethanol Port-Fuel-Injector Position on Dual-Fuel Combustion in an Automotive-Size Diesel Engine NOx ; CO ; THC ; Aldehydes N/A Britto and Martins [8] Present work NOx ; CO " THC " Aldehydes " ⁄ There might be different results in the above emissions trends depending on engine running conditions. Please cite this article in press as: Britto Júnior RF, Martins CA.…”

Performance effects and economic viability of high-hydrated ethanol fumigation and diesel direct injection in a small compression ignition engine

“…The low ethanol cetane number caused more ignition delay, and consequently higher rate of heat release. As a result, there was a reduction of heat lost to the cylinder walls and increase thermal efficiency [5,8]. Oliveira et al [6] report in their research 13% increase in efficiency when use ethanol fumigation on diesel engine.…”

“…Jamuwa et al [8,24] investigated the performance, emissions and combustion parameters in a stationary engine of compression ignition using ethanol fumigation. The engine is monocylinder, stroke is 3.7 kW, and compression ratio is 16.5.…”