Economical and environmental factors together with energy policies towards more efficient systems are the driving force for the development of the vehicle industry. Significant changes have been made to fulfill new emissions legislation but the basic internal combustion vehicle architecture has been kept.
New emission treatment systems that increase the thermal loading of the cooling system had been added within the same package envelope as before, which means less space to place cooling fans and a greater need for airflow. Changes in the cooling system, namely the replacement of the hydraulic fan drive system by electrical fans is one of the energy efficient alternatives for several city buses under certain environments, like the ”typical red city buses”, well-known in the United Kingdom.
In this thesis study, hydraulic fans are compared with electrical fans and a road-map of the benefits and drawbacks of the two systems is developed, based on real traffic performance data and the results of existing simulations and tests. In addition, new simulations are presented in order to find the most efficient design for the cooling system as well as a comparison of these results with previous ones. This road map will be used later by Volvo-Buses Group as a tool to better understand in which circumstances electrical fans can be beneficial, in terms of fuel consumption, noise production, cooling performance, control of the fans and associated costs.
Author: Fernandes, Rita