Estimation of Energy Conservation in Internal Combustion Engine Vehicles Using Ionic Liquid As an Additive

Lubricants play a vital role in improving energy efficiency and reducing friction in any type of frictional contact. The automotive industry is facing strict regulations in terms of emissions from the petroleum fuel. Strict government norms are compelling automotive manufacturers to push their technological limits to improve the fuel economy and emissions from their vehicles. Improving the efficiency of the engine will ultimately result in saving fuel thus improving the fuel economy of the engine. Concerning energy consumption; 33% of the fuel energy developed by combustion of fuel is dissipated to overcome the friction losses in the vehicle [1]. Out of this, 11.56% of the total fuel energy is lost in engine system. The distribution of this 11.56% fuel energy lost in engine system includes 3.5% consumed in bearings, 1.16% in pumping and hydraulic viscous losses, 5.2% and 1.73% consumed in piston assembly and valve train respectively [1]. If we consider losses only in bearings, piston assembly and valve train it results in 10.4% energy loss as compared to the total energy generated by the fuel. In the last decade, ionic liquids have shown potential as lubricants and lubricant additives. This study focusses on the use ionic liquids as additives for friction and wear reduction resulting in energy conservation in an internal combustion engine. In this work, the contact between piston ring and cylinder wall was simulated using a ball-on-flat tribometer. Most of the engine oils are based on mineral oils and results showed that adding 1% of the ionic liquid to mineral oil reduced friction loses by 27% [2], which corresponds to conserving 2.8% of fuel energy if just the frictional loss in piston assembly, valve train and bearing are considered. In the United States, there are 253 million vehicles on average consuming 678 gallons of fuel per year [3], the use of ionic liquid can save an estimated 4.8 billion gallons of fuel per year, which results in estimated saving of 11.56 billion dollars.