Development Of DA465QA Series Engine

With the development of our national economy, the automobile went into people’sfamily. Automobile industry as the important function of stimulating consumption has alsoappeared, various provinces and cities will be automobile industry as the focus of theregional economic development, but with the increasing number of automobile, automotiveemission pollution and energy consumption has become the economic development mustsolve the problem, therefore, from2000, China started referring to European automobileemissions regulations step by step build up China’s automobile emission regulations system,and gradually narrow the gap with developed countries in Europe and America.At the sametime in fuel consumption, according to the national conditions of China and graduallyestablish relevant laws and regulations. This makes each big auto companies to increase theengine development in terms of investment, keeping up with the engine technologydevelopment trend, the new technology applied to engine development project, for example,turbocharger、 cylinder direct injection、 variable technology. Improving the engineperformance, reduce fuel consumption.Dongan company is domestic micro gasoline engine main suppliers, and DA465Qengine is Dongan company’s main model, from the beginning of1980s in mass production,and to now have more than20years of history, the product technology has lag behind, inorder to meet the national laws, regulations and the requirements of market competition, weneed to improve engine performance level. Therefore, from the beginning of2004, Dongancompany began the DA465Q engine upgrade development technology demonstration, Andwith AVL, EV, LOTUS, ORBITAL and ROUSH foreign engine professional developmentcompany for technical exchange, communication range includes the project application ofadvanced technology, technical indexes,cost, production line construction, the marketprospect, etc. Upgrade development project overall goal is to meet the second stage of thefuel consumption started on January1,2008, to meet the Europe IV emission standard. At the same time to meet the national standard requirements of economical automobile. Enginelitres power reached more than45kW, matching the vehicle fuel consumption to the secondstage fuel economy regulations limit value.This article mainly introduced the DA465QA engine development work, the keycomponents of engine such as intake manifold, exhaust mainfold, cylinder port, developmentprocess and work contents carry on the detailed introduction, work in the development of theapplication of the advanced test technology and simulation development technology is alsopresented, to improve the engine independent development level, to form the independentdevelopment ability has great significance.Development of engine upgrades of the original DA465Q type machine based on,maintain the DA465Q engine displacement, the basic structure of small change.Optimization design of intake and exhaust port, engine has absorbed resonance boostingcapability at various speeds. Also make full use of friction reduction technology, improvingthe mechanical efficiency of the engine. In2valve structure, also has the very highperformance, use this engine has the very high performance ratio. This ensures that the fullutilization of the existing production lines, reduce production line transformation andinvestment cost.In the engine development,a comprehensive grasp of the prototype machineperformance level through prototype comprehensive evaluation, determines the optimizationdirection, at the same time for the subsequent application simulation technology provides theaccurate data support. Establishing the engine working model using one-dimensional engineworking process numerical simulation software Ricardo WAVE7.1, the model of WAVEcalibration ensures model machine state consistency.Based on the prototype evaluation conclusion, the engine performance improvementshave affect is the compression ratio, valve size, port dimensions, intake manifold, the valvelift and the exhaust manifold etc, combining design experience to determine the initialimprovement scheme.In concept development phase, the cam profile, the port, the intake manifold, the exhaust manifold, catalyst and so on concept design, make sure the following conclusion.1、Prototype compression are small, only8.8. The engine is knock highlights the needfor the engine to have an increased compression ratio,which will improve both full loadperformance, and part load fuel economy.2、Increasing the valve diameter and the wider inlet and exhaust ports increased theperformance above5000r/min. The slight reduction in performance below5000r/min is dueto the unmatched valve timing. This was expected, as improving the flow efficiency withoutoptimsing the valve timing will result in reductions in performance at lower engine speeds.Great improvements are gained in this area after valve timing optimization.3、The concept cam profiles have higher lift and the later timing. The new profilesresulted in improvements in performance above5000r/min. The gains are not as high below5000r/min since these generic concept profiles are suited to high speed. As above, greatimprovements are gained in the low speed region after valve timing optimization.4、The concept inlet manifold boosted performance above4000r/min but reducedperformance below. This is expected from the tuning effects of the longer primary runnerlength. Again the low speed region improves after valve timing optimisation.5、The new exhaust concept is4to1, again the reduced volumetric efficiency is due tounmatched valve timing.6、The new catalyst made no difference to volumetric efficiency and torque as expected,since it is not a major flow restriction.In the engine design phase, mainly introduced the valve system, intake manifold,exhaust manifold, air intake system, cylinder head port, and other key parts of the design anddevelopment process.In valve system design, according to the prototype of valve system structure size,establish Valdyn model using the Ricardo Valdyn4.0valve system simulation analysissoftware. The model is calibrated according to the valve lift of the simulation results andmeasured values for comparison and verification. According to the simulation results ofRicardo WAVE, establish a new valve system model, and design new CAM profile, make sure the structure dimensions and parameters of the valve system, and then evaluation valvesystem design rationality through the valve system in kinematics and dynamics analysis.In the intake manifold design, according to the concept design preliminary certainparameters, based on the series of combinations of parameters simulation of volumetricefficiency, choose to consider the high and low speed condition parameters as the intakemanifold of the final solution.In the exhaust manifold design, according to4-1type pipe structure in the conceptdesign, the performance simulation results show that a longer exhaust pipe can get peakperformance in3000~3500r/min. But long exhaust pipe is limited in the actual enginearrangement and cabin space. Determine the exhaust pipe length close to100mm, thecollertor configuration is step divergent scheme which constitutes a gradual section changefrom26mm to50mm at the catalyst attachment flange.Cylinder head port development including inlet port,exhaust port and combustionchamber development. Manufacturing single cylinder machine model and using flow testbench for single cylinder machine model for flow testing, the test results are compared withthe prototype.The inlet port development including the inlet valve head diameter increased from31.6mm to32.5mm, inlet valve stem diameter reduced from7mm to6mm, design new portshape. The exhaust port development including the exhaust valve head diameter increasedfrom27.6mm to28.5mm, exhaust valve stem diameter reduced from7mm to6mm, designnew port shape. Combustion chamber development including design new combustionchamber shape, repositioning spark plug position.In the engine development and validation stage, introduced the intake manifold and theexhaust manifold structure design process. The CFD analysis of the intake manifold and theexhaust manifold use thesoftware STAR-CD. Modal and the stress distribution analysis ofthe intake manifold and the exhaust manifold use the finite element analysis softwareANSYS, and finally determine the intake manifold and the exhaust manifold structure size.Through the engine performance verification, DA465QA engine test performance have reached the target of development requirements.