Experimental Research Of Engine Heat Balance Based On Coolant Temperature

Energy Saving and Emissions Reduction have become one of the hottest topics in2012.With the sustained production growth and automobile sales, China has become the world’slargest car market, and car ownership is growing at a rapid rate, resulting in serious airpollution. In early2012, Beijing publishes PM2.5readings as well as an air-quality index,China has demonstrated through its actions that she had already begun to emphasize autoemissions. Automotive emissions have ungraded from the state III to the State IV, and thegovernment is going to pursue the implementation of the state V. With the arrival of lowcarbon energy, energy conservation and emissions reduction, low carbon development hasbecome a major challenge for sustainable automotive growth. From the engine technologyaspect, the design of the engine has two sides: one is improving the engine thermalefficiency; another is reducing engine emissions. With the development of modern enginespeed and power, engine will have increasing heat load, thus cooling system demand ahigher level than conventional engine. Cooling system’s function is to make sure that theengine can work reliably with the most suitable temperature in any load conditions andworking environments. It is an important part of the engine, because cooling system ingasoline engines will directly affect power performance and fuel economy. It is a researchdirection of the gasoline engine cooling system in the future.This thesis research object is a certain PFI engine, researching the engine heatdistribution principles and influencing factors based on the engine coolant temperature.There are three variables (coolant temperature, engine speed and load). In this experimentalscheme, the engine coolant inlet temperature is set at90℃and100℃. Engine speed isvariable which starts to change from1000r/min to6000r/min. Engine load is variable whichstarts to change from15%to100%. According data calculation and analysis, this paperdiscusses the engine coolant and heat distribution impacts of the engine speed and loadchange. Through experiment we can obtain the coolant pressure characteristic curve,temperature characteristic curve and flow rate characteristic curve in different working conditions; and also analyzed the heat distribution principles and influence factors. Datacollection is based on the MAP way. We can get a lot of data, and analyze the experimentaldata. We can provide a series of empirical parameters for independent development anddesign for the new cooling system. At last, this thesis brings forward an optimized designscheme based on the sum-up and analyses to improve the thermal efficiency of the gasolineengine.This main research contents in this thesis are as following:(1) Built a test bench of engine heat balance, and completed the debug of testequipment and engine.(2) Measured mechanical loss by bench test.(3) Through experiment we can obtain the coolant pressure characteristic curve,temperature characteristic curve and flow rate characteristic curve in different workingconditions (Coolant inlet temperature set at90℃and100℃).(4) Researched the engine heat distribution principles and influencing factors based onthe engine coolant temperature in the engine full-load characteristic conditions (coolant inlettemperature set at90℃and100℃).(5) The difference of the engine heat distribution is compared and analyzed when theengine coolant inlet temperature set at90℃and100℃.(6) Analyzed the experimental data, and proposed an optimized design scheme.