Studying Ignition Delay Time of Lubricant Oil Mixed with Alcohols, Water and Toluene in IQT and CVCC

Abstract

The auto-ignition of liquid fuel and lubricant oil droplets is considered as one of the possible sources of pre-ignition. Researchers are continually finding new ways to form advanced lubricant oil by changing its composition and varying different oil additives to prevent the occurrence of this event. In this study, three sets of mixtures are prepared. The first set of mixtures was prepared by adding different alcohols namely ethanol, methanol and propanol, to the commercial lubricant oil (SAE 15W-40) in ratio of 1 -5 % by vol The second set of mixtures were prepared by mixing SAE 15W-40 with aforementioned alcohols (1 % vol.) and H2O (1 % vol.). Lastly, third set of mixtures were prepared by adding SAE 15W-40 in toluene (1 % -5% by vol.). Two experimental setups were used in the current work. An Ignition Quality Tester (IQT) was used investigate the mixtures' ignition delay time (IDT) following standard ASTM D6890 procedure, while a constant volume combustion chamber (CVCC) was used to investigate the combustion characteristics of burning of a suspended single oil droplet. For the CVCC, experiments were carried out in an ambient air environment at 300 °C with varying pressure ranging from 4 bar -22 bar at 6 bar interval pressures.IDT of lubricant oil was considered as the base IDT, which was compared to those of other mixtures. Addition of alcohols and water in lubricant oil showed a significant increase in IDT compared to other mixtures. However, the addition of toluene resulted in a decrease in IDT. Among the alcohols, methanol addition showed highest IDT compared to ethanol. However, alcohols had to be added >4 % by vol., to show a significant increase in IDT compared to pure lubricant oil.

Study of the Effect of Research Octane Number on the Auto-Ignition of Lubricant Oil Surrogates (n-Hexadecane)

“…Lubricant oil in highly boosted spark ignition engines is believed to be a significant cause of pre-ignition . Hence, several study groups − are paying particular attention to engine lubricants’ effect on the occurrence of pre-ignition. Lubricant oil is diluted by fuel sprays from direct fuel injection directed toward a wall, leading to a local reduction in the surface tension and viscosity of the oil .…”