Search Results

The assembly of con rod bearing and crankpin is a key friction pair which offers an important guarantee for stable operation of diesel engine. Specific to the non-road 2-cylinder diesel engine developed independently and based on the theory of thermoelastohydrodynamic lubrication as well as multi-body dynamics, this paper establishes a multi-body dynamics model for con rod big end bearings of the 2D25 horizontal diesel engine and makes a research on the influence of bearing width, bearing clearance, and oil inlet position and diameter upon lubrication of con rod bearing, taking into consideration that of the surface appearance of bearing bush and the elastic deformation of bearing bush and axle journal upon the same. Research results show that bearing width and bearing clearance are the major factors that influence lubrication characteristics of con rod bearing while oil inlet position and diameter only have a small influence on such characteristics.

In order to fulfill the technical requirements of a high-efficiency low-emissions off-road horizontal diesel engine, a unique design is proposed and optimized in this paper for the cooling water jacket structure with a forced-cooling closed-loop cooling system. The cooling water flow rate, temperature, and pressure at the inlet and several other critical locations of the cooling water jacket were measured and analyzed at different engine operating conditions for the water jacket designs. A numerical simulation model of the coolant flow and the cooling system was built and used to analyze the thermal/fluid characteristics of the coolant flow in the water jacket. The impact of different structural and packaging design parameters on coolant flow and heat transfer was investigated. The design deficiency of an original (earlier) design of the water jacket was pointed out and an improved design was proposed.

When diesel engines operate at regions with different altitudes, there are differences between their operation properties. The properties of diesel engines at different atmospheric pressures have been studied by means of a micro-computer controlled atmosphere-simulating system. The properly differences of the diesel engine between different atmospheric pressures have been analyzed in detail. Some new dimensionless parameters have been set up to analyze the operation properties of diesel engines at different atmospheric pressure. The conclusions contribute to analyzing and improving the properties of diesel engines at regions with different altitude, and remodify the standard of the atmospheric amendment for diesel engines.