Studies on the effect of higher compression ratio on the engine behaviour fuelled with used transformer oil

ABSTRACT

Preliminary investigations on the utilisation of used transformer oil (UTO) as an alternative fuel in a single cylinder, four stroke diesel engine developing 4.4 kW power at a rated speed of 1500 rpm showed a marginal increase in brake thermal efficiency (BTE) and reduction in smoke emission when this was operated with optimum injection timing of 20° bTDC and injection pressure of 23,000 kPa. The present investigation is aimed to study the effect of varying the compression ratio (CR) of the same engine fuelled with UTO, under optimum injection timing and injection pressure. At lower CR, the maximum cylinder pressure, ignition delay, BTE and unburned hydrocarbon (HC) emission decreased by 10.3%, 10.7%, 3.4% and 17.5% respectively at full load, whereas nitric oxide (NO) emission increased by 5.9% at full load. The study also reveals that at higher CR the maximum cylinder pressure, BTE, HC and NO emission increased by 11.2%, 22.3%, 2.7% and 30.6% respectively at full load, whereas it shows 15.1% shorter ignition delay at full load.

KEYWORDS:

• Diesel engine
• variable compression ratio
• used transformer oil
• combustion
• performance
• emissions

Disclosure statement

No potential conflict of interest was reported by the author(s).