A Purely Mechanical Energy Storing Concept for Hybrid Vehicles
The paper contains the design and simulation of a purely mechanical system for storing energy during vehicle deceleration, which can be utilized during subsequent acceleration (regenerative braking). A continuously variable transmission (CVT) regulates the energy transfer, energy storage is accomplished by means of a spiral spring and additional use of a planetary transmission. The transmission ratio of the CVT is adapted by a combined feed-forward and feed-back control. A computer simulation for a vehicle with an overall mass of 1500kg, and an energy storage capacity of 30kJ was performed for different driving cycles. In a typical urban stop and go situation the proposed device will save up to 0.72kg fuel per 100km and the overall efficiency analysis together with simple design, easy recycling, and long life expectance, showed a clear advantage over other hybrid concepts for frequent stops and accelerations.
Energy recovery systems for retrofitting in internal combustion engine vehicles: A review of techniques
Energy recovery systems (ERSs) for internal combustion engine vehicles (ICEVs) are reviewed in the context of fuel efficiency improvement and retrofit capabilities. The paper presents technical knowledge on the potential benefits that retrofitted ERSs may achieve in carbon emissions reduction. A first distinction of ERSs is made between the sources of the energy and further sub-divided on the technique to harvest and store the energy. A critical evaluation is performed on the associated characteristics such as weight, size and cost. Finally, the paper summarizes the ERSs technologies under a number of common criteria, and finds out, that the most effective ERSs in terms of fuel efficiency are the ones more difficult to retrofit. Further research is suggested to investigate the trade-off between fuel consumption reduction and investment cost of the system.
A Comparison of Modeled and Measured Energy Use in Hybrid Electric Vehicles
CarSim 2.5.4, written by AeroVironment, Inc. of Monrovia, California and SIMPLEV 3.0, written by Idaho National Engineering Laboratory were used to simulate two series-configured hybrid electric vehicles that competed in the 1994 Hybrid Electric Vehicle Challenge. Vehicle speed and battery energy use were measured over a 0.2-km maximum effort acceleration and a 58-km range event. The simulations` predictions are compared to each other and to measured data. A rough uncertainty analysis of the validation is presented. The programs agree with each other to within 5% and with the measured energy data within the uncertainty of the experiment.