Application of VDAS for Determining the Performance Characteristics of Petrol and Liquefied Natural Gas in an Internal Combustion Engine

Abstract

In Nigeria, on May 29, 2023 the price of Premium Motor Spirit (PMS) was increased by 195% from N185/liter to N545/litre while the price of Liquefied Natural Gas (LNG) dropped by 18% from N720/kg to N600/kg during this period of time, this development made many people to switch from PMS to LNG as fuel for operating their generating set. The aim of this work is the application of Versatile Digital Acquisition System (VDAS) for determining the performance characteristics of Petrol and liquefied natural gas in an internal combustion engine. The experimental setup employed a TD200 four-stroke petrol test engine, adapted for the Tec-Equipment TD200 small engine test bed, a hydraulic dynamometer, a dual carburettor and a VDAS. Performance parameters such as torque, power, air mass flow rate, Brake Mean Pressure (BMEP), volumetric efficiency, and exhaust gas temperature were measured and analyzed. Petrol provided higher torque at lower rpm while LNG produced more power at higher speeds, peaking at 2521W with 3800 rpm compared to Petrol's 1876 W. LNG achieved a higher BMEP (5.28 bar) at 2900 rpm than Petrol. Petrol exhibited higher volumetric efficiency (85.7% at 2300 rpm) compared to LNG (82.27% at the same speed), with both fuels showing decreased efficiency at higher speeds. In terms of fuel consumption savings, using LNG as a fuel can significantly reduce fuel usage. The findings from the studies revealed that overall that, LNG offers better performances than Petrol, hence, preferable for an engine application.