The Cooling System Improvement For 6170 Diesel Engine Based On Increasing Power

As the power for the marine propulsion,the Weichai 6170 diesel engine owns a great market share.It’s concluded by an market survey that greater torque at the low speed range is needed by the customer.Therefore we have to increase the power and torque in order to improve the product competitive power and satisfy the market demands.The power and torque of the current engine increased alone,liner scuffing,carbon deposit on the piston ring,yellowness on the bottom of the piston and injector failure are seen in the durability test.With a primary analysis we believe these failures result from the high thermal load and the cooling insufficiency.So an analysis of the cooling system and an evaluation of the cooling capacity have to be made.What’s more,we have to modify the structure of the cooling system to enhance the engine cooling capacity.Combined with the real cooling system,we build the 1D calculation model of the whole cooling system through the Flowmaster software.Subsequently,the steady state calculation of the flow volume and pressure distribution for both the rated condition and high torque condition is done.So is the evaluation of the cooling pump flow volume.Based on the 3D model of the cooling system and the 3D CFD calculation of the water passage,we analyze the uniformity of each cylinder and get the flow volume and pressure distribution of the water passage.After the analysis of the water passage,especially the high thermal load areas like the cylinder head bridge and liner top area,the low heat expansion area or the dead area of the cooling system is finally found.Regarding these issues,we modify the structure of both the cylinder block water passage and the cylinder head water passage and improve the flow condition.As a result,the dead area is avoided,the flow speed of the cylinder head bridge increased and the cooling capacity of the exhaust valve area improved.We run a durability test,and liner scuffing,carbon deposit on the piston ring and yellowness on the bottom of the piston don’t show up anymore.This proves that the cooling capacity of the structure-modified cooling system has been improved greatly and is able to meet the cooling demand of the enhanced 6170 diesel engine.