The Design And Research Of Variable Valve Timing Inlet And Outlet Camshaft Control Of GDI Engine

As vehicle exhaust emissions is one of the main reasons that caused atmospheric haze in Chin a. Beijing, Shanghai, Tianjin and some other first-tier cities has took measures such as the even1icense plate rule to control the number of vehicles. The development of economy should not at t he expense of the environment.During these years, many auto manufacturers have launched so me new engines attached with many advanced technologies including direct injection(ordinary with DVVT and sometimes with Variable Calve lifting), turbo charging, mechanical supercharg ing, variable cylinder management and so on. There also some small-displacement but high-po wered vehicles, such as the three-cylinder LOT eco boost GDI engine which with Aluminum all oy cylinder block, the increasing power could reach92kw and the max-torque could reach170n. m. These kinds of engines have considerably increased the power output of small-displacement engines and decreased the fuel consumption and exhaust emissions which could have equivalent power to2.0Lengine. Direct injection engine shortened as GDI, FSI, SIDI and so on) has beco me one of hot spots because of its high thermal efficiency, low fuel consumption, good perform ance of antifriction and low emission. Electronic control unit (ECU)’s soft and hardware develo pment, as an important component and the core technology of GDI engine area has become the central of the research.Software design in ECU module is an important and difficult point of the electronic developi ng system, which involves module’s function, strategy, communication, algorithms, control logi c and so on. During the whole process of the research, the other colleagues in the lab finished th e GDI engine and ECU hardware’s integrated design for engine bench test, which including the knock signal detection circuit, Ignition driving circuit, injection drive circuit, sensor signal proce ssing circuit, VVT electromagnetic valve actuator drive circuit and so on.This thesis is focused on the strategy of the software design for the engine with vane type VV T system. The VVT air intake and exhaust camshaft control strategy is designed based on the ac quiring of expectation value of the phase and relative position judgment of crank signal, therefor e get the differential signal.And maps of P, I, D parameters were calibrated, use the PID control ler, delivering the useful duty cycle to OCV. Then according to the control of Solenoid valve oi1and spilled oil pathways by hydraulic pressure, the phase of camshaft will change, therefore a djusting the air intake and exhaust valve timing,optimizing the process of cylinder inlet and exh aust valves and at the end increasing the volumetric efficiency, improve the power take-off and f uel economy.The simulation results show that through the PID control, the camshaft phase can a ccording to the target response accordingly well.