Study On 4G69 FR MIVEC Engine Oil-water Mixed Problem

The paper mainly studies the oil-water mixture problem has occurred with 4G69 FR MIVEC engine production early,through to the fault parts analysis,ensure that determine the cause of the 4G69 FR MIVEC engine oil-water mixed fault is the existence of shrinkage cavity defect of cylinder head bolt hole position tenth.The 4G69 FR MIVEC engine cylinder head casting process of the temperature test,confirmed the tenth screw hole shrinkage cavity porosity is due to feeding bad.Through the improvement of temperature field,adjusting the casting parameters,increase the feeding channel process measures,eliminate tenth bolt hole shrinkage cavity problem.Verified by the production,4G69 FR MIVEC engine cylinder head qualified rate at about 97%.The sample cutting verification,tenth bolt holes without obvious shrinkage cavity.The heat transfer and thermal expansion calculation,4G69 FR MIVEC engine cylinder head to increase the feeding channel change,the engine cooling and the thermal expansion deformation affect compliance with technical requirements of drawings.In order to verify the casting process improvement effect on the 4G69 FR MIVEC to improve the performance of engine cylinder head,before and after the casting of Pin hole degree,hardness testing,testing demonstrated improved degree and hardness before and after 4G69 FR MIVEC engine cylinder Pin hole degree had no obvious change,technical requirements are in line with the cylinder head.In order to verify the casting process improvement effect on the 4G69 FR MIVEC engine performance,using AVL AC electrical dynamometer,according to the condition of the engine test,respectively before and after the improvement of cylinder head 4G69 FR MIVEC engine performance test.By comparison the torque at low speed,the maximum torque value,the maximum power output and fuel consumption values of important parameters such as engine performance before and after improvement is not much difference,are better than the original machine performance,performance meet the design requirements.In order to improve the 4G69 FR MIVEC engine cylinder head casting process,avoid the influence of environmental temperature on the casting temperature field.With the environmental temperature,temperature of liquid aluminum,cooling air pressure as the input vector,cylinder head casting qualified rate as the output vector,designed the BP artificial neural network simulation.Through the test,to prove the design of network has good performance and can be predicted in the corresponding relationship between the environment temperature,set the temperature of liquid aluminum,and the qualified rate of the cast cooling pressure between.