Petroleum fuel prices are touching the sky. Consumption and production of petroleum products have been increased. On the other hand, exhaust emission is not good for anyone in the world. NOx, CO2, particulate matter (PM) and other dangerous chemicals entered into the human body and cause dangerous diseases.
The simplest way to improve the emission and performance problem is fuel additives. Fuel additives are the chemical compounds that are added in the engine to improve the efficiency and emission quality. They are added in a small amount to enhance the performance of the engine. Oxygenated additives have the potential to improve the combustion process inside the combustion chamber [Pandian, Manuswamy, Radhakrishnan, Nagappan, and Devarajan 2017]. Oxygenated fuels are sustainable sources of energy and their oxygen atoms improve the combustion process. Alcohol and ether both have high oxygen content, low viscosity, and significant density which makes them the appropriate additive for the compression ignition engine [Kumar, Nayyar, Bafna, Agarwal, and Prakash 2015]. Some fuel additives are discussed below.
DIETHYL ETHER
Diethyl ether is also known as Ethoxyethane, Diethyl oxide, and ethyl ether. Diethyl ether is an organic compound which is a volatile, colorless and highly flammable liquid. Diethyl ether works as a solvent for a variety of organic compounds. DEE is having a high cetane number, low autoignition temperature, high volatility, and high oxygen content. It is a very effective fuel in a sub-zero temperature zone for starting of the engine in a cold climate. One of the exceptional properties of the DEE is that it burns smoothly the rich fuel region in the combustion chamber.
- High volume of diethyl ether with diesel promotes knocking in the engine [Lee & Kim 2017]
- Smoke, NOx and PM can reduce by adding DEE with diesel in the CI engine [Anand & Mahalakshmi 2007].
- BTE 7.2% increased and BSFC 6.7% decreased when diesel engines were given to diethyl ether with diesel [Ibrahim 2016].
- HC and CO can be minimized by DEE and diesel blend.
ETHANOL
Ethanol is also known as ethyl alcohol. It is a flammable and colorless liquid. Ethanol is the most prominent alternative fuel for gasoline engines. Ethanol is also a good fuel additive among all alcohols for CI engines. We can obtain ethanol from various sources like sugarcane, sugar beets, corn, and waste biomass materials. Ethanol is a favorable alternative fuel for CI Engine due to its properties like a low flash point, low boiling point, and high oxygen content. It is also a safe additive because of its low flashpoint. Ethanol gives us better and complete combustion compare to diesel. Ethanol has the potential to reduce emissions from the engine.
- Ethanol has a capability to reduce the PM and NOx of the exhaust emission [Kumar, Rana, Tripathi, and Gupta 2018].
- Dissolving in diesel ethanol can reduce the emissions of the vehicle.
- The amount of ethanol increased the HC and CO from the engine’s emission [Xu, Qi, Zhang, and Cai 2007].
- Brake Thermal Efficiency and Break Specific Fuel Consumption Both increases with the amount of ethanol.
