Energy Saving Potential Of Passenger Car Gasoline Engine Lubrication System

With the release of China fourth stage fuel consumption regulation,a series of measures has been adopted by passenger car companies to save energy,which include the mechanical loss reduction of lubrication system,such as using variable displacement oil pump,matching between oil and lubrication system,oil rapid warm up,etc,to achieve saving engine energy.Variable displacement pump energy saving is based on on-demand supply,requiring accurate understanding of the engine oil demand components.After analyzing these demands,it is found that it is difficult to master the exact requirements of hydraulic tappet and variable valve timing,but these requirements can be reduced by controlling strategy optimization.In addition,the crankshaft oil demand is calculated in detail.It is found that the oil consumption increased with engine speed.Through engine bench tests,the oil pressure under the rated conditions can be reduced to the low level of 300 kPa.This thesis analyzes different types of variable displacement pumps,and focuses on vane pumps.The results show that the energy saving potential of one stage variable displacement pump under the low speed and low load conditions of passenger vehicles is limited.Solenoid valve two stages variable displacement pump has currently the highest cost efficiency,with good matching between its main energy saving zone and common running conditions.The theoretical calculation and bench test shows that 1N·m torque reduction can be achieved using the solenoid valve pump at 90?,2000r/min,resulting in about 1.5% fuel consumption reduction in the new European driving cycle(NEDC).In addition,through the switch of its high and low pressure mode,the flexible control of the injection timing of the piston cooling nozzle can be realized.The main objective of lubricant matching optimization is to reduce the friction resistance,including the use of anti friction agents and the reduction of viscosity grade.In this paper,the influence of the amount of antifriction agent and the viscosity grade from 40 to 30 and 20 on friction resistance is analyzed,and its energy saving potential is above 2% through the engine bench test and the vehicle NEDC cycle test.Finally,the rapid warm up of lubricating oil is roughly studied.It's found the electric heating has no energy-saving benefits,while the exhaust heating is an effective means to reduce the friction resistance,but it needs to solve the cost problem of the heating system.