The growing transportation sector worldwide has opened up a way forward not only for the scientists & researchers but also for the OEMs to find out the options for fuel efficient automotive vehicles with reduced emissions during their usage. The demand of automotive vehicles has been doubled in last few years and in turn the market for lubricants and transmission fluids are flourishing. Several new formulations of lubricants are getting popularized with major suppliers to achieve the end user expectations in terms of fuel economy benefits, engine life and emissions. The market trend is continuously moving towards the improvement in lubricant formulation to the lower viscosity ranges and in this direction several companies are into development of multi-grade low viscosity range of engine oils (lubricants) which is said to be providing the benefits in terms of fuel economy. Also during past few years the low viscosity range of lubricants is getting popularized with OEMs for fuel economy improvement and other added benefits.
For validation of the analytical results (laboratory based analysis) of low viscosity range of lubricants the chassis dynamometer based performance evaluation on BS-II Light Commercial Vehicle (LCV) was undertaken and performance tests were successfully completed on small truck using four (04) formulations in terms of different viscosity ranges in terms of kinematic viscosity of engine oil (one reference & three candidate formulations). The performance evaluation tests were carried out with the help of chassis dynamometer facility, emission system and gravimetric fuel balance. The test protocol was standard which is being followed in all national laboratories and test centres across the country. The driving cycle for the subject test on vehicle was Delhi Bus Driving Cycle (DBDC) and the test was done keeping the temperature of 25°C±2°C in test cell.
Four (04) set of tests were carried out on the same test vehicle for different kinematic viscosity formulations of 10W30 grade namely X1 cSt, X2 cSt and X3 cSt (in terms of decreasing viscosity ranges) in comparison with reference formulation of 15W40 grade with kinematic viscosity of 14.6 ct. The percent improvement of the candidate oil formulations in term of gravimetric based fuel economy was marginal.