Optimized Matching Of Key Components For CA4D20Diesel Combustion System

With the increasingly prominent energy and environmental issues, countries around theworld have launched increasingly stringent emissions regulations to control emissions ofharmful pollutants from cars. Currently, China is promoting the implementation of China IVemission regulations, to face the market demand, and improve the company’s productcoverage, FAW Sihuan Co., proposed a "diesel car CA4D20of State IV emission standards"project.The match quality of diesel engine combustion system key components is critical to thecombustion process and emissions of harmful contaminants, it must make the cylinder airmovement, the shape of the combustion chamber, the oil distribution and placement of theoil all have good matching characteristics, etc.. Thus, it can make sure the cylinder can formhigh quality combustible gas mixture, and improve the combustion process in the cylinderand reduce emissions of harmful pollutants. As the prototype is the company’s new products,the supercharger, injectors, combustion chambers, camshafts and other key components allneed fully optimize match and design, in order to make the CA4D20to meet the State IVemission standards. The results of the study are as follows:First, the preliminary prototype performance analysis results showed that: thepreliminary prototype has a bad low-speed performance, high extinction smoke and fuelconsumption rate. It is crucial to make the prototype successfully achieve the national IVemission standards, and improve its low-speed performance.Second, the development of the process has a research of the optimized matchingbetween the combustion and fuel injectors.①I type combustion chamber has a higher fuel consumption, and significantlydeteriorated soot emissions during low-speed segment. Ⅲ type combustion chamber has ahigher fuel consumption and extinction smoke during low-speed segment, and it is also aslightly soot increase during high-speed segment. In most of the conditions,Ⅱ type combustion chamber has a lower fuel consumption and emissions of smoke, is the bestchosen of the prototype.②I type injector at low speeds can get better fuel economy and emissions of smoke,but it is deteriorated in the high-speed segment. Ⅲ-type injector has a relatively high averagebasic fuel consumption and extinction smoke. Ⅱ type injector has a relatively higherextinction smoke and fuel consumption at low speed, but other conditions have a betterperformance and have a optimum adaptation of the prototype.③1.5mm gasket thickness has a better match performance with the prototype inhigh-speed zone, but the fuel consumption and extinction smoke has a significantlyincreased at low speeds.3.0mm gasket thickness has a higher fuel consumption and highextinction smoke than2.5mm gasket thickness over the entire engine operating. When thegasket thickness is2.5mm, it has a better match of the prototype.Third, use the GT-power software, different characteristic of the supercharger wascalculated. According to the calculation results of the supercharger optimized selection andprocessing, after GT-power simulation analysis, the original supercharger has a bad matchwith the prototype. It has low supercharger efficiency in high load area. Through the jointanalysis with the supercharger plant, JP44F23, JP44F29and JP44F3were selected to makethe experiment. The result shows that: JP44F3turbocharger performance is good in allaspects of performance, so this paragraph supercharger is suggested to be used. Meanwhile,JP44F3turbocharger’s preload is more suitable to the original prototype. When the preload isincreased or decreased, the performance of engine high speed segment will be worsened.Fourth, camshaft and the exhaust pipe the engine performance can be greatly improvedafter the optimized designing.Meanwhile, after the optimized matching of the combustion chamber, turbocharger,camshaft and the exhaust pipe size, the engine speed performance improved. In low velocityzone (<2200r/min), the intake air inflows and air fuel ratio increases, the extinction smoke,fuel consumption and CO emissions are significantly improved, and it laid the foundation forthe prototype to achieve the national IV emission standards.