Search Results

Architecting and integrating commercial hybrid electric vehicles (HEV) is a long and labor intensive process which is unique every time. The challenge intensifies when one attempts to create an HEV capable of engine-off operation. In this case, electrical power needs to be supplied to devices which are normally powered by the engine accessory belt. These devices are referred to as e-accessories. To address the issue of time to market and reduce vehicle integration burden, a plug-and-play architecture for connecting e-accessories has been developed. The Flexible High Voltage DC System is analogous to a USB hub on a PC and serves to provide power, control and communication to e-accessories such as electrified power steering, electrified brakes and electrified HVAC.

Commercial vehicle operators and governments around the world are looking for ways to cut down on fuel consumption for economic and environmental reasons. Two main factors affecting the fuel consumption of a vehicle are the drive route and the driver behavior. The drive route can be specified by information such as speed limit, road grade, road curvature, traffic etc. The driver behavior, on the other hand, is difficult to classify and can be responsible for as much as 35% variation in fuel consumption. In this work, nearly 600,000 miles of drive data is utilized to identify driving behaviors that significantly affect fuel consumption. Based on this analysis, driving scenarios and related driver behaviors are identified that result in the most efficient vehicle operation. A driver assistance system is presented in this paper that assists the driver in driving more efficiently by issuing scenario specific advice.

Vehicle electrification is being actively expanded into coming generations of passenger and commercial vehicles. This technology trend is helping vehicles to become more energy efficient. For electric vehicle (EV) city bus application, the system designers have been experimenting with a number of options including direct drive and multi-speed gearbox architectures. Direct drive scenario offers simplified drivetrain system, however requires a large and powerful electric motor. Multi-speed transmission system provides an opportunity to reduce motor size and optimize its operating points, but increases complexity from the architecture and controls point of view. This paper provides an overview of several common system layouts and examines their advantages and disadvantages. Vehicle simulation results are presented to compare direct drive vs. multi-speed technology from the gradeability, acceleration and energy consumption points of view.