Evaluation Of Energy-saving Effect Of Lubricant Based On Engine Test

Lubricant, as the blood of engine, not only protects engine under safety operation, but also has effects on reducing friction loss, cooling, cleaning and sealing. With tightening regulations, OEMs have more severe environmental requirements for lubricant. This research focuses on the effects of lubricants quality on automotive engine fuel economy based on engine test evaluation.At present, the most important lubricants quality test systems in the world are American Petroleum Institute(API) which closely connects with International Lubricant Standardization and Certification Committee(ILSAC) and Association des Constructeurs Europeens(ACEA). Both have specialized evaluation and test specifications for lubricant energy saving. But these methods cannot fully link the energy-saving effect of lubricant with real driving conditions.This research comes from practical engineering applications. A car manufacturer requires the vender to develop a new generation of energy-saving lubricant which can provide 0.8% at least fuel economy than current ILSAC GF-5, 5W-20 products. Meanwhile, setting up a new engine bench test method is to simulate the vehicle New European Driving Cycle(NEDC), which is in order to evaluate energy-saving product performance.Firstly, this paper identifies two goals to simulating including vehicle speed and coolant temperature based on real-world NEDC; On the basis of lab capability, this paper sets up a total NEDC simulation engine test platform based on engine hardware in loop strategy, using Automotive Simulation Models, dSPACE system and AVL dynamometer; On the above platform, the paper investigates coolant temperature control. Through investigating two methods(engine test bench external water tank circle and vehicle cooling system), the paper chooses vehicle cooling system control that temperature is close to the real vehicles. Meanwhile, screening tests by SRV and High Frequency Reciprocating Rig(HFRR) are utilized to determine the feasibility of different friction modifier formulations. Finally, the total NEDC simulation engine test bench plus vehicle cooling systems control system is selected to verify energy saving effect of different lubricant formulations and final formulation.The test results show that it is feasible to evaluate lubricant energy saving effect through total NEDC simulation engine test bench. And the engine test bench coolant system based on vehicle cooling system control has high correlation with real vehicle temperature curve. The final lubricant formulation is 0W-20 Group base oil blended Ⅲorganic molybdenum friction modifier. Compared with ILSAC GF-5, 5W-20, the energy saving of the new lubricant formulation is up to 1.18%, which exceeds the requirement of the car manufacture.