Research On Matching Of Turbocharge System For GDI Engine

With the development and progress of economy, an increasing quantity of oilconsumption spreads all over the world every year. As a kind of nonrenewable energy source,measures should be taken to avoid overuse of oil. In the face of energy crisis, people try theirbest to save energy and protect the environment all over the world. At present, oilconsumption by auto motives account for a considerable proportion of total consumption.More and more families own a car by themselves in China, leading to the rapidly expandingcar ownership year by year all around the world. Therefore, it is imperative to start energysaving and emission reduction of automotive engine.Compared to PFI (Port Fuel Injection) engine, GDI (Gasoline Direct Injection) enginehas the advantage of high thermal efficiency, low oil consumption and low emission and soon, which is the direction of development of automotive engine in future. Withoutconsuming engine output power, turbocharger technology, as well as wide low fuelconsumption and cost, is an effective method to improve power performance of internalcombustion engine.However, matching of the turbocharged system on gasoline engine is different from thaton diesel engine. First, gasoline engine has a high heat load and is easy to knock. What’smore, it has a wide variation range of engine speed. Then, as turbocharger technology juststart to be applied to gasoline engine, some methods suitable for diesel matching onparameter setting and selecting empirical formula should be adjusted so that these methodscan be used for gasoline engine.For these reasons, this paper is based on national "863" project " the development ofgasoline direct injection engine on a car". According to the gasoline direct injection engine,on which the turbocharging system is installed, we implement the matching research onturbocharging system of GDI engine. The work of the following respects has been done inthis paper:1. Research on the structure and working principle of the turbocharger for GDI engine, grasp the process and method of intake and exhaust relevant theoretical and turbochargingmatching of internal combustion engine. In addition, on the basis of the above, combiningthe work characteristics of gasoline engine, determine the matching way of turbochargingsystem and gasoline engine.2. Using the thermodynamic model formula of every component, calculate theparameters which influence the working characteristics of every component in GDI engine.The calculations contain calculation of important parameter in turbine performancecharacteristic curve, as well as thermodynamic calculation of gas exchange in enginecylinder and intake and exhaust pipes. At last, the values of important parameter which aresuitable for GDI engine.3. Using one-dimensional numerical simulation software AVL-Boost, conduct theone-dimensional complete machine modeling of GDI engine with turbocharging system.According to analogue computation and comparative analysis of test bench results under fullload and engine speed condition, the model is validated.4. According to the calculation of gas consumption characteristics by one-dimensionalcomplete machine modeling of GDI engine and research on matching of turbochargingsystem by the method of analyzing turbine performance characteristic overlying curve,theresult shows that under the condition of heavy load the turbocharger can work moreefficiently at the operating point in the matching simulation, indicating that theturbocharging system can improve power performance of GDI engine, as well as a goodmatch with GDI engine.5. Conduct heavy load bench test at the operating point in the matching simulation witha GDI engine. Obtain the data of intake and exhaust pressure, temperature, etc. at heavy load.Compared with the value of the simulation match, the error is less than5%. The resultproves that turbocharging system can meet the match need of GDI engine in this paper.