The effects of urban driving conditions on the operating characteristics of conventional and hybrid electric city buses (original) (raw)
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© Published under licence by IOP Publishing Ltd. Regenerative braking is a way to harvest electric energy from braking mechanism which usually implemented in electric vehicles. Braking strategies are required to maximize the use of regenerative braking systems. This research aims to design a regenerative braking model for a medium-sized electric bus. Measurements of latitude, longitude, elevation, and speed were firstly conducted by using GPS-based OsmAnd Android application. Transjakarta Corridor 1 (Kota-Blok M) was used for a test track with a distance of 14 km. Besides using data from measurements using GPS, WLTP (Worldwide Harmonised Light Vehicle Test Procedure) data is also used for comparison. This study produced a braking strategy model that considers aerodynamic, rolling, and grade resistances as well as electrical component specifications of the electric bus. The model design is then compared to the existing serial and parallel strategy. With the design of this system, the regenerative braking model can harvest more energy which increases the mileage of the electric bus.
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The extended-range electric vehicle (E-REV) is an electric vehicle concept that has a light engine to allow an extended driving range. One of the most important features of these vehicles, based on electricity, is their ability to recover significant amounts of braking energy in a process known as regenerative braking. The more driving motor operates widely as generator, the more braking energy can be absorbed. However, it is not realistic in terms of performance for components. This study proposes three regenerative braking torque maps as the constraints to consider their performance. The results of fuel economy for simulations while applying proposed torque maps are compared with those of simulations without any constraints to evaluate effect of regenerative braking for E-REV bus according to characteristic of driving cycle. The characteristics of driving cycles are analyzed to find relationship between driving cycle and fuel economy. The aggressiveness of the driving cycles shows a linear relationship with regard to the difference in the fuel economy. This result can be used to develop power distribution control strategies with regenerative braking models to improve fuel economy levels.
The need for improved fuel economy for road vehicles has increased the interest in hybrid electric vehicle (HEV) and recovering vehicle energy. This paper aims to evaluate the amount of kinetic energy that could be restored through regenerative braking in a HEV. This work will not resort the Brazilian urban driving cycle NBR 6601, for this cycle does not fully represent a pattern of traffic faced regularly in urban areas, which is typically composed of heavy traffic and long periods of idleness. Therefore, a new drive cycle will be developed that better represents the Brazilian traffic. Also, considering the shortage of energy resources, the large amount of energy dissipated as heat during braking a vehicle is a recurring concern. Therefore, measuring the maximum available energy that could be restored through regenerative braking is the first step towards estimating the profit of using this technology and how it would pay off the investment in the long run. Thus, a longitudinal vehicle dynamics model is implemented using MATLAB/Simulink in order to simulate a small-size hybrid vehicle undergoing the cycle set up and assess the energy balance looking forward to the energy available for recovery.