Oxygenated Fuel Additive Option for PM Emission Reduction from Diesel Engines—A Review

Abstract

As on today, of the two types of engine used in mobility sector, diesel engines offer superior fuel and thermal efficiencies, better durability, greater torque, and higher power output compared to the gasoline engines. However, the diesel engines are a major source of both regulated and unregulated emissions which is responsible for the deteriorating air quality. The problem can be tackled either by using alternate power plant such as hybrid and electrical vehicles or by using alternate source of energy like biodiesel and oxygenated additives to diesel. The second option seems to be more attractive, as it does not need any major modification to the millions of existing engines. In this direction, there is an urgent need to find sustainable and environmentally friendly fuel types for the diesel engine application. In this chapter, the authors embark on the analysis and review of the application of oxygenated alternative fuels such as biodiesel, acetone–butanol–ethanol (ABE) solution and water emulsion as oxygenated fuel reformulation strategies. These strategies are aimed at achieving reduction of engine particulate emissions without much compromise on energy efficiency of the diesel engine. After the careful review of around 115 published literature, it is found that, still more research under controlled conditions is a must on these oxygenated fuels to gain more insight on their effects. This is especially true for the emissions of particulate matter (PM). Further, it is brought out through this review, a combination of factors such as higher oxygen content, more complete combustion and cooling effect to reduce this pollutant. If employed appropriately by having a diesel blend which contains proper amount of biodiesel, ABE solution and a small amount of water (0.5%), the regulated PM emissions can be reduced considerably. What it means is that such oxygenated fuels exhibit excellent performance in both brake thermal efficiency (BTE) and NO_x–PM trade-off. This chapter proposes an oxygenated diesel fuel blend not only for scientific study but also for the future practical application.

Appendix: Influence of Various Oxygenated Fuels on NOx and PM Emissions

Engine details	Test details	Blend details	NOx	PM	References
DI diesel gen. set 4 cylinders, water-cooled engine	Tests carried out under steady-state condition at 75% of maximum load	Water–diesel	–	22.2–44.0% ↓	Lin et al. (2006)
		Water with NOE-7F-natural organic enzyme-7F + diesel	–	31.1–61.4% ↓
Yanmar S.P. Co, Ltd, Thailand DI diesel, single cylinder, water-cooled engine	Tests carried out under steady-state condition at 80% max. power output of 3.2 kW	Butanol (10–25%)–diesel	9–21% ↓	4–28.4% ↓	Lin et al. (2012)
		Butanol (10–25%)–water (0.5%)–diesel	13–25% ↓	13–25% ↓
		Butanol (10–25%)–water (1%)–diesel	14–36% ↓	14–36% ↓
Kirloskar India DI diesel single cylinder. water-cooled engine	Tests carried out under steady-state condition with varying BMEP (bar)	Algae methyl esters (10%) + diesel	25% ↑	–	Yilmaz et al. (2014)
		Algae methyl esters (15%) + diesel	27% ↑	–
		Algae methyl esters (20%) + diesel	34% ↑	–
Yanmar S.P. Co, Ltd, Thailand DI diesel engine, single cylinder, water-cooled engine	Tests carried out under steady-state condition at Idling, 1.6 and 3.2 kW	Neat soybean oil (1%) + diesel	3.7–4.5% ↑	7.1–22.7% ↓	Zhou et al. (2014)
		Soybean Biodiesel + diesel	1.8–2.5% ↑	7.9–27.3% ↓
		Water-containing, acetone + isopropyl, alcohol + soybean oil	1.9–13.9% ↓	1.7–31.8% ↓
		Water-containing Acetone + isopropyl alcohol + soybean biodiesel	9.1–15.7% ↓	14.3–36.4% ↓
		Pure acetone + isopropyl alcohol + soybean oil	5.79–12.0% ↓	11.1–31.8% ↓
		Pure acetone isopropyl alcohol + soybean biodiesel	8.26–13.9% ↓	14.3–36.4% ↓
Mitsubishi DI diesel, four cylinders, water-cooled engine	Tests carried out under steady-state condition at 50% load (rated power 12 kW and Torque 50 Nm)	2% microalgae biodiesel	2.0% ↑	22.0% ↓	Fraioli et al. (2014)
		2% microalgae biodiesel + 20% butanol	25.0% ↓	57.2% ↓
		2% microalgae biodiesel + 20% butanol + 0.5% water	28.2% ↓	59.5% ↓
(i) Mitsubishi DI diesel, four cylinders, water-cooled engine	(i) Tests carried out under steady-state condition	B25A25	15.6–22.7% ↓	11.6–15.8% ↓	Chang et al. (2014)
		B50A25	10.1–21.3% ↓	16.2–22.7% ↓
		B75A25	9.50–19.3% ↓	10.9–18.5% ↓
	(ii) US-HDD transient cycle with Cummins B5.9-160	B-biodiesel, A-Water-containing ABE solution
(ii) Cummins DI diesel turbocharged water-cooled engine, Diesel generator set, Anhui Quan Chai Group Corp. China): DI diesel, water-cooled engine	Tests carried out under steady-state condition: 125 Nm, (75% of maximum load)	Soy biodiesel (10–30%)		22.4–57.5% ↑	Lin et al. (2008)
		Water with surfactant (10%) + soy biodiesel (10–20%)		57.5–58.8% ↓
		NOE-7F water (10%) + soy biodiesel (10–20%)		87.7–89.6% ↓
Yanmar S.P. Co, Ltd, Thailand DI Diesel, single cylinder, water-cooled engine	Tests carried out under steady-state condition three modes of operations: Idle, 1.6, 3.2 kW loads	Biodiesel–diesel blends	0.8–14.1% ↑	5.0–47.9% ↓;	Lee et al. (2011)
		Ethanol–biodiesel–diesel blends	0.9–10.9% ↓	3.7–65.6% ↓
Yanmar S.P. Co, Ltd, Thailand DI diesel engine single cylinder, water-cooled engine	Five modes of operation: 1500 rpm, 1800 rpm, 40 Nm, 80 Nm	ABE10		20.8–27.0% ↓	Lin et al. (2008)
		ABE20		24.7–43.5% ↓
		ABE30		28.7–48.8% ↓
		ABE10W0.5	0.8–14.1%	27.9–39.0% ↓
		ABE20W0.5	0.9–10.9%	37.5–61.1% ↓
		ABE30W0.5		47.3–62.5% ↓
		ABE-acetone–butanol–ethanol W-water content
Yanmar S.P. Co, Ltd, Thailand DI diesel, single cylinder, water-cooled engine	Not specified	Waste cooking oil biodiesel (1–70%) + diesel (99–30%)		2.3–35.5% ↓	Lee et al. (2011)
		Biodiesohols waste cooking oil biodiesel (1%) + acetone (1–3%) + 1% isopropanol + diesel		3.6–15.3% ↓
Yanmar S.P. Co, Ltd, Thailand DI diesel, single cylinder, water-cooled engine	Not specified	Biodiesohols waste cooking oil biodiesel (3%) + acetone (1–3%) + 1% isopropanol + diesel		10.5–18.4% ↓	Lee et al. (2011)
		Biodiesohols waste cooking oil biodiesel (5%) + acetone (1–3%) + 1% isopropanol + diesel		11.4–19.1% ↓
		Biodiesohols waste cooking oil biodiesel (10%) + acetone (1–3%) + 1% isopropanol + diesel		19.8–27.5% ↓
		Biodiesohols waste cooking oil biodiesel (20%) + acetone (1–3%) + 1% isopropanol + diesel		35.4–37.5% ↓
Diesel engine generator (QC495, Anhui QuanChai Group Corp. China): direct injection; water-cooled	Tests carried out under steady-state condition at 125 Nm—[75% of maximum torque]	Palm biodiesel blends (10–30%) + Diesel		7.0–45.5% ↓	Chen et al. (2010)
		16% BioSolutions + palm biodiesel (10–30%) + diesel		88.6–89.4% ↓

1. ↑ Increase
2. ↓ Decrease