Human powered energy efficient vehicle design

Abstract

Recent awareness in energy consumption and environment has generated interest in ecofriendly transportation system in both developed and developing regions of the world. Government and private sectors are encouraging innovative development and use of energy efficient vehicles for transportation of people and goods. Design and development of such systems is a popular design issue in both academia and industry. In this paper, an industry sponsored student project for design and development of a human powered transportation system is presented. It allows a single rider to move in all types of terrain by transferring power to the drive train through the use of a biodegradable hydraulic fluid. Besides the design criteria specified by the project sponsor, functionality, safety and reliability, manufacturability, and cost effectiveness are focus of this design process. Overall design objective is to minimize the weight and maximize energy efficiency of the low power hydraulic drive train. Among the innovative human powered transportation ideas, an upright carbon fiber configuration is adapted. It optimizes rider comfort, weight and provides support of all hydraulic components and drive train. The pedal power of the rider runs a fixed displacement axial piston pump and transfers the pressurized fluid to a hydraulic motor of similar classification driving the rear wheel. A pressure sensing hydraulic circuit allows storage of the pressurized fluid in a hydraulic accumulator and releases the fluid on demand such as during the uphill motion. A light weight mechanical drive train provides appropriate torque to drive the pump and driving wheel under all driving conditions. In the spring of 2012 the system will participate in a national design competition among twelve engineering schools. The designs will be evaluated based on established design criteria and performance of the system in a 200 m sprint, 10.8 mile endurance, and an energy recovery efficiency race. © 2012 American Society for Engineering Education.