Design features of fan assembly in automobiles

Abstract

Nowadays in the engine cooling system and in air-conditioning system of passenger compartment and cabin of tractor is applied a great variety of designs of fan units for the supply of cooling air. A distinctive feature of fan units of automobiles is that they need not only to supply cooling air, but also must make efficient use of air flow. This is not an easy task, because these two functions are almost always in conflict. The problem becomes even more complicated when a car air conditioner is installed. Efficiency factor of the incident flow is higher than the efficiency of the fan. It is therefore necessary to use more efficient the incoming air flow. The article analyzes the most common fan assemblies of automobiles used for the operation of the engine cooling and passenger compartment air conditioning system. Its strengths and weaknesses were evaluated. There were evaluated the most important characteristics: the effectiveness of the fan use, the rational use of air flow when the vehicle is moving, mass-dimensional characteristics and the noise produced by the fans in their work. The conclusions and recommendations for improving the fan installations were given. When choosing one or another variant of the fan assembly it is needed to take into account the features of the automobile design. High efficiency of fan can be obtained when the fan shroud has a full coverage of the radiator. In this case, for rational use of incoming flow is necessary to install in the fan cover the valves of a large cross-section in contrast to traditional, these valves must be driven to forced opening and closing.