In the condition that the engine structure and parameters have not been altered,the 100 h experimental study was carried out with the 4D160 diesel engine when using the commercial -10 diesel and the methanol diesel(-10 diesel with 20% methanol) as fuel oil.The dynamic and economic properties of the engine,the friction and wear properties,detergency and the change of metal content in the lubricating oil of the engine at different time points were compared and studied.The experimental results show that the power and fuel economy of the engine using methanol diesel are decreased,and the decrease of fuel economy is more obviously under heavy load.When methanol diesel is burned,more acidic substances are produced,which makes the acid value of lubricating oil increase rapidly,resulting in the increase of engine wear,and the wear amount of cylinder sleeve is the largest.In the 100 h experiment,the 100 ℃ kinematic viscosity of the lubricating oil shows a downward trend when using diesel and methanol diesel as fuel oil,and there is a larger decrease of the viscosity of lubricating oil when using methanol diesel as fuel oil.When using methanol diesel as fuel oil,the total mass of engine deposits is smaller than that when using diesel as fuel oil,and the engine detergence score is slightly higher than that when using diesel as fuel oil.