Performance Simulation And Test Research On Dongan DA5 Series Gasoline Engines

In the future automotive industry will face double chanllenge: energy efficiency and environmental protection, so energy saving and emission reduction will become the main product development goals of every vehicle enterprise and engine plant at home and abroad. With tightening constantly of the domestic and foreign regulations for emission and fuel consumption, releasing constantly the automotive industry polices and the climbing of oil price, the technical level of the engine is being improved continuously. Meanwhile, it shortens the period of development, decreases costs and risks largely to use the advanced development means. The domestic and foreign gasoline engines with advanced world level are being devoloped continuously.Considering the development of national mandatory laws and regulations,the competition in the domestic auto market and engine status in the company,Dongan decide to use advanced technology to develop DA5 series gasoline engines with the relatively higher comprehensive technology level. So Dongan can stable the market position of the gaoline engine of the economical car step and step. DA5 engine family has three kinds of displacement consisting of 1.0L, 1.3L and 1.5L engines. Every displacement includes the basic engine without variable valve timing (VVT) and the high performance engine with VVT and exhaust gas recirculation (EGR).DA5 family considers the two layout schemes with front drive and rear drive.Meanwhile, the engines will share the components as much as possible in DA5 family. In concept design and layout design phases, the author simulates and optimizes the valve timing and structure parameters of intake system, and prodicts the full load performance of DA5 engine family by using AVL-BOOST and modeFRONTIER. The main work consists of the following parts:Detailed description of the algorithm and mathematical model of AVL BOOST, optimization theory. Model setup and calibration of 1.1L engine in K engine family according to boundary conditions defined by engine targets and design constraints. The results show that the simulation error is less than 6% and the model can be used to optimize the parameters and predict the performance of the DA5 engine family.Determination of some parameters of DA5 engine family. Below are the dimensions of the relevant components dericed from the statistical datas and the referenced prototype: Rated speed: 6000 rpm Compression ratio: 10.5 Intake valve diameter: 28.5 mm Exhaust valve diameter: 24 mm Inner intake valve seat diameter: 26 mm Inner exhaust valve seat diameter: 21.5 mm Max intake valve lift: 8.5 mm Max exhaust valve lift: 7.74 mmInvestigation on valve timing of 1.5L VVT engine and optimization. The exhaust valve closing, EVC of 8°CA ATDC is recommended according to the simulation results.The intake valve opening,IVO at different speeds of 1000,2000,3000,4000,5000 and 6000rpm is 27°CA BTDC, 39°CA BTDC, 20°CA BTDC, 13°CA BTDC, 2°CA BTDC and 12°CA ATDC respectively.Investigation on intake system of 1.5L VVT engine and optimization.The recommended intake system dimensions are: IN_Snork_L: 255mm IN_Snork_D:64～60mm IN_Zip_L:275mm IN_Zip_D:55mm IN_Run_D1:35mm IN_Run_D2:37mm IN_Run_D3:37mm IN_Run_L1:370mm IN_Run_L2:340mm Volume of Intake receiver (plenum): 1.0LInvestigation on valve timing of 1.5L engine without VVT and optimization. The EVC of 8°CA ATDC and the IVO of 2°CA BTDC is recommended.Prediction of full load performance of the 1.5L engines. The result shows, that the maximum power and the maximum torque of vvt engine is 76.41kW at 6000rpm and 143.56N·m at 3000rpm respectively, the minimum brake specific fuel consumption, BSFC is 259.5g/kW·h. The results reach the targets of 76.4kW and 137.9N·m. The maximum power and the maximum torque of engine without VVT is 75.21kW at 6000rpm and 138.86N·m at 3000rpm respectively, the minimum BSFC is 260.2g/kW·h.The results reach the targets of 74.9kW and 131.9N·m.Investigation on valve timing of 1.3L VVT engine and optimization. The exhaust valve closing, EVC of 9°CA ATDC is recommended according to the simulation results.The intake valve opening,IVO at different speeds of 1000,2000,3000,4000,5000 and 6000rpm is 42°CA BTDC, 42°CA BTDC, 31°CA BTDC, 20°CA BTDC, 6°CA BTDC and 7°CA ATDC respectively.Investigation on valve timing of 1.3L engine without VVT and optimization. The EVC of 9°CA ATDC and the IVO of 6°CA BTDC is recommended.Prediction of full load performance of the 1.3L engines. The result shows,that the maximum power and the maximum torque of vvt engine is 68.08kW at 6000rpm and 120.3N·m at 3000rpm respectively, the minimum BSFC is 270.01g/kW·h.The results reach the targets of 66.2kW and 119.5N·m. The maximum power and the maximum torque of engine without VVT is 66.48kW at 6000rpm and 118.72N·m at 3000rpm respectively, the minimum BSFC is 267.98g/kW·h. The results reach the targets of 65kW and 114.4N·m.In the performance test phases, the author conducted plenty of test study on the performance of 1.3L engine without VVT, such as mechanical loss, the influence of valve timing on net power at full load and the bsfc at part load, the influence of oil on the performance, the pressure in the cylinder, the flow rate of the intake and exhaust port in the cylinder head and fuel consumption for the passenger cars.The work covers in detail following topics:Determination of the mechanical loss.The mechanical loss of 1.3L engine without VVT is relatively lower than similar engines.Investigation on the influence of cam phasing on the full load performance and determination of intake and exhaust valve timing. The exhaust valve closing, EVC is 5°CA ATDC. The exhaust valve opening, EVO is 35°CA BBDC. The intake valve opening, IVO is 5°CA BTDC and the intake valve closing, IVC is 41°CA ABDC.Prediction of full load performance. The maximum power and the maximum torque is 66.92kW at 6000rpm and 118.05N·m at 4500rpm respectively.The results reach the targets of 65kW and 114.4N·m.Determination of the part load BSFC at 2000rpm/2bar.The result is 395g/kW·h or so.Investigation on the influence of oil on the part and full load performance.?With the increase of viscosity of lubrication oil, the mechanical loss increases slightly and the Power performance and fuel economy decrease slightly. The quality class and the brand of lubrication oil influence slightly on the performance of the engine.Determination of the pressure at different crank angles in the cylinder.The maximum pressure in different cylinders of 1^st, 2nd, 3^rd and 4^th is 74.8bar at 5000rpm, 76.3bar at 5500rpm, 76.9bar at 5500rpm and 76.4bar at 5500pm respectively.The friction mean effective pressure, FMEP and heat release rate also is determined to provide the detailed boundary conditions for simulating further the performance of the DA5 1.5L engines.Determination of the flow coefficient of intake and exhaust port in the cylinder head to provide the detailed boundary conditions for simulating further the performance of the DA5 1.5L engines. The mean flow coefficient of intake and exhaust port is 0.3703 and 0.4007 respectively.The ports of these four cylinders have a good coherence.The maximum deviation value of intake and exhaust port is 1.44% and 2.35% respectively that they are less than reference value of 3.0%.The flow coefficients of every intake or exhaust port at different valve lift have a high coherence.The combined fuel consumption of HAFEI Junyi and Luzun mini van assembling DA5 1.3L gasoline engine without VVT is 6.8L and 7L respectively. They are less 2.94% and 2.78% respectively than the third stage limits of fuel consumption for passenger cars (Opinion Soliciting Draft).They have obvious competitive advantages in the passenger cars with the same levels.