| In recent years, with the rapid growth of cars as well as the increasinglyserious energy and environmental issues, the Beijing-six, four-stage fuelconsumption regulations to be enacted soon,"high-power, low fuel consumption,low emissions" become the development direction and goals of automotive enginetechnologies, the application of the new control technology and the precise controlare the means to achieve this goal. Gasoline direct injection and turbo charger arethe two important technologies for the optimization and innovation of gasolineengine today, more and more car manufacturers would like to apply them toproduct vehicle types, so the research of turbocharged gasoline engine (TGDI)control technology is especially significant. TGDI engine control system throughadjusting the parameters of the intake, ignition, and fuel injection, then export thedesired engine torque and power. Due to the properties of gasoline equivalentburning and the strict requirements of catalytic converters to the air-fuel ratio,therefore the accurate control of intake air can improve combustion, thus reducingfuel consumption and emissions. It can be said, to the intake air system of TGDI’sengine, the electronic control system is the most important component.In this thesis, it takes4GA13TD engine type as the research object, which isdeveloped by FAW.4GA13TD‘s intake control system must be able to accuratelycalculate the engine intake air, and it can be accurately determine the electronicthrottle opening angle and boost pressure in real-time, make the engine obtain thedesired air mass flow, make sure the engine combustion stability in the wholeconditions, the torque is accurate, emissions will be achieve the law requirements.The control system is the complex multi-input and multi-output system, in order toreduce costs, it take the double-MAP rather than MAF+MAP as sensors, whichadds to the complexity of the control algorithm, the study has great applicationvalue.Thesis focuses on the following two aspects:①Establishing the relative air charge control model, including identify therequired intake air mass flow and calculate the residual gas of cylinder.Through the torque demand to determine the required intake air mass flow, thisis in order to determine the electronic throttle opening angle. Given theimportance of the intake air system of TGDI, the control algorithm is designed to take redundancy. This thesis calculates the relative air charge and air massflow by the slope-intercept method and speed-density method,cross-checking between the two methods, and the results of the two methodsverificate each other, also can be replaced each other when a failure occurs,this is to avoid engine shut-off accident.②Design of the turbo control model. Control algorithm based on the law ofenergy balance, according to the ideal gas equation of state, compressor andturbine acting mechanism, combined with the compressor and turbinecharacteristics of the data, taking a double loop feed forward plus feedbackcontrol algorithm to finalize the control of waste gate valve, and then it cancalculate the desired boost pressure. This thesis also designed the dump controllogic for engine surge phenomenon. The control of turbo charger engine canincrease the amount of intake air, and thus enhance the engine’s power; it alsomeans significantly in the parts of engine downsizing and reduces fuelconsumption.Finally, the control of the proposed algorithm has been verificated on the4GA13TD engine test bench at all conditions. Compare with bench measurementdata, the air mass flow which is calculated by the relative air charge control modelis achieved the system metrics; the turbo control model can be realized on a fasthigh-precision control of boost pressure, the difference between the actual boostpressure and the desired boost pressure is no more than50hPa, and the test data ofthe steady-state and the transient conditions are met the system requirements. |
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