Performance Improvement And Test Evaluation Of Automotive Gasoline Engine Based On Turbocharging Technologies

This research was focused on upgrading a1.0L naturally aspirated engine into aturbocharged engine,to replace a the1.3L naturally aspirated engine in a vehicle. Powered bythe1.0L turbocharged engine vehicle dynamics is aimed to1.3L engine，and the vehicle fuelconsumption should saves upto5%.Firstly, one-dimensional simulation software GT-Power was utilized to creat a simulationmodel for the1.0L naturally aspirated gasoline The model was then calibrated and validatedagainst experimental data.Two turbocharger models were proposed based on the boostingtarget requirements and the derivated pre-selection formula.Later,detailed GT-Powersimulation results indicated that GT12turbocharger is more suitable for the engine.Then,the inlet and exhaust manifold system were optimized for the turbocharged enginemodel.Analysis of the different valve overlap angle indicated that increasing the valve overlapangle was expected to improve the low-speed torque.A knocking module was developed andutilized to analyze the influence on engine knock index of compression ratio and sparktiming,which provided the theoretic support and direction for engine design change and testscheme.Exhaust gas temperature increase after turbocharging,and the influences of the air/fuleratio were analyzed.and put forward relevant suggestions for reducing the exhaust gastemperture.Finally,according to the test results, comprehensively comparion of performance betweenthe turbocharged engine and the original naturally aspirated1.0L and the1.3L gasolineengines.Compared to the baseline engine, the turbocharged engine had an increase of torqueby41.7%.At2000r/min the turbocharged engine does not meet the performance goal,butswitching to smaller turbines or using VVT technology was expected to improve the low-endtorque. As expected,the fuel consumption rate of turbocharged engine is higher than baselineengine,mainly due to reduced compression ratio and the retarded igntion timing which lead toa thermal efficiency drop.Compared to the1.3L naturally aspirated engine，the power ofturbocharged engine was higher than that of1.3L naturally aspirated engine，but the low-endtorque of turbocharged engine was poorer.Vehicle fuel consumption rate was simulated,underthe New European Driving cycle (NEDC),powered by the1.0L turbocharged engine,Vehiclelevel fuel consumption rate can be ruduced by5.18%,with equivalent dynamicperformance,which meets the desired performance objective.Further reduction of vehicle levelfule consumption rate can be expected by reducing the exhaust back pressure of the turbocharged engine.