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In this paper, the characteristics of particle size distribution in the exhaust of a turbocharged 5.9 liter Cummins gas engine lubricated by two commonly used oils of different viscometrics (15W-40 and 20W-50) have been investigated. The study also attempts to differentiate the performance of the lubricants on the basis of fuel economy. A test procedure developed in- house was used for the evaluation, wherein the engine was operated at various speeds (1200-2800rpm) and load (25 %, 50% & 75%) conditions. Particle size distribution is measured using Engine Exhaust Particle Sizing Spectrometer (TSI EEPS Model 3090). Results indicate that a majority of the particle emissions are observed in the nucleation region (particle diameter < 50nm) and particle size distribution is found to significantly vary with engine speed.

The ever increasing demand of fuels for vehicles can only be met by use of alternate fuels like Compressed Natural Gas (CNG) and Hydrogen (H2). The 18 percent hydrogen enriched CNG fuel referred to as HCNG has the potential to lower emissions and is considered to be the first step towards promotion of a Hydrogen economy. While, automotive industry matures up with the usage of new engines, lubricant manufacturers are also moving on to the next stage by formulating oils to be used in gas engines such as CNG, HCNG etc. This paper presents the evaluation of gas engine oil on 6-cylinder heavy duty CNG engine using HCNG. The six cylinder engine was chosen due to its importance for urban bus transportation. The engine was optimized for using HCNG fuel. Initial performance of the engine using HCNG was compared vis-à-vis CNG and, thereafter, the engine was subjected to endurance test of 500 hours as per 8 mode engine simulated driving cycle.

Depletion of fossil fuel reserves, the unsteadiness of their prices and the increasingly stricter exhaust emission legislation put forward attention of world towards use of alternate fuels. The ever increasing demand for ecologically friendly vehicles can be met by use of clean fuels like Compressed Natural Gas (CNG) and Hydrogen (H2). Lower carbon to hydrogen ratio of CNG makes it a cleaner fuel, due to this CNG is gaining popularity as an internal combustion (IC) engine fuel in transport sector. Hydrogen fuel for IC engines is also being considered as a future fuel due to its simple carbon less structure. However, several obstacles have to be overcome before widespread utilization of hydrogen as an IC engine fuel can occur in the transport sector. The 18 percent hydrogen enriched CNG fuel referred to as HCNG has the potential to lower emissions and could be considered a first step towards promotion of a Hydrogen economy.

In this paper, experimental evaluation was carried out on a 6.0 L heavy duty CNG engine which has been optimized for 18 percent hydrogen blended CNG (HCNG). Optimization test results shows that use of HCNG results in reduced CO, THC & CH4 emissions by 39, 25 & 25 percent respectively and increase in NOx by 32 percent vis-a-vis CNG. After optimization the engine was subjected to endurance test of 600 hours as per 15 mode engine simulated city driving cycle with HCNG. The performance & emission characteristics of the engine were analyzed after completion of every 100 hours as per European Transient Cycle (ETC). Test results indicate that there were no significant changes observed in engine power output over the complete endurance test of 600 hrs with HCNG. Specific fuel consumption (SFC) measurements were consistent at all the 15 modes of engine simulated city driving cycle.