This report describes the design, manufacturing, analysis, and control activities students conducted for small sized electric vehicles. In 1997, the Kochi University of Technology opened. Since then, the students tried to design and manufacture the electric vehicles in the extra-curricula class and in the laboratory. Engineering education for mechanical engineering needs the practical design and manufacturing, since design and manufacturing is the key of engineering. We would like to report the 9 years activities in our laboratory since 1997. We started the production for joining the Kochi Eco-power Race in Kochi in 1997, and for joining the Shikoku Electric Vehicle Rally in Shikoku Island in 1998. Since then, the vehicles we produced are the one converted from a light weight conventional vehicle, two small-sized electric vehicles with four wheels, the one with three wheels, electric motorcycle, and electric tiller. Besides such activities of design and production, the stress analysis and control had been conducted. For renewable energy utilization, we need to consider how to charge the batteries for electric vehicles. We might be able to use the fuel cell battery in the future. In order to charge the electricity for electric vehicles, we planned to use the self-powered electricity, which is produced by a wind-solar hybrid power system. The self-powered street light whose electricity is from wind and solar panel was installed in our university. The experiment had been conducted using the system, and the capability was studied.
From the viewpoint of aging society in Japan, there is a need for vehicles adaptable for the elderly. Author et al. have developed an ultra small electric vehicle, which has a driver assist system suitable for elderly drivers. This system can take into account the various profiles among the elderly drivers, by monitoring the status of the driver and changing the vehicle response by means of by-wire technology. Driver-monitoring vehicle was developed based on this ultra small electric vehicle. This vehicle was equipped with measuring instruments, which monitors many aspect of driver's status. It was designed to monitor driver's operations and vital reactions in sync with vehicle conditions to find out the way to support drivers. In order to verify the function of the driver-monitoring vehicle, EMG measurements were taken. Effective measuring points of EMG were the tibialis anterior for braking and the deltoid muscle for steering. In the driving experiment, EMG rise occurred 0.5 second before driver's operation was implemented. And the feasibility of support system using EMG was indicated.
When a lead-acid battery deteriorates, the specific gravity of the acid electrolyte gradually decreases from the initial value (1.28) to 1.18-1.20. However, in our laboratory's study, the specific gravity value increased from 1.28 to 1.32-1.36 after the charge. This is very unusual. Our various results have been reported regarding this behavior. The specific gravities of batteries after discharging also gradually (but faster than the case of after charging) increased with repeating charge-discharge cycles. One of the reasons for accounting these phenomena is thought to be due to the production of fine particles of Pb and PbO2 the recovery form the sulfation by repeating cycles of low-rate charge and high-rate discharge accompanied with the use of additives such as organic polymers.
We have been investigating the prolongation of the life-time of lead-acid batteries in the view point of environmental aspects and material resources. Since 1997, we have been working on the activators for lead-acid batteries. We developed various activators using composite organic polymers with solid powder, organic polymers, etc. The effects of prolongation of life-time have been compared between our activators and the other commercially available additives, using actual 6 V batteries for motor cycles. The change in the internal resistance of batteries has been measured during discharge-charge cycles to clarify the deteriorating mechanism. Organic polymer P is useful for prolongation of the life-times of lead-acid batteries if it is used with a suitable amount. The solution of electrolyzed carbon particles with 2.00 ms/cm is also effective for enhancement of the battery performance, and more effective if it is used together with a small amount of organic polymer. The internal resistance of the battery becomes a good index of deterioration of the battery.
One of the advantages of ultracapacitors is its high power capability, which is applicable for high rate of charging and discharging operation like motor starting and regenerative braking of an electric vehicle. This paper presents a new charging method for ultracapacitors. Comparing with batteries, ultracapacitor can accept a wide range of charging current and can be fully charged within a few minutes. Common chargers for ultracapacitors are usually equipped with current transducers and closed loop circuitry for current control, which are expensive and complicated. The proposed circuit consists of a minimum number of components. It does not require any current transducer or dedicated voltage/current control circuitry. A simple open-loop control system is applicable for the whole charging stage. It is free of stability problem and protects itself from being overloaded by ultracapacitor with zero initial charge. This paper presents the design and operation of the hardware circuit. Both simulation and experimental results are included.
Electrification of a transportation device makes it possible to achieve quietness and high-performance control. Electric vehicles have been developed based on such kind of thought. Wheel Chairs might get comfortableness and excellent mobility by electrification. The conventional electric powered wheel chair, PWC, has, however, the following disadvantages due to universal functions: (1) heavy weight makes it difficult to store especially in-house use when it is not in use, (2) the design of PWC is somewhat out of place with surrounding furniture, (3) PWC cannot easily turn in a limited house space. We have made a new powered wheel chair named "mobile chair" which has excellent features solving the above-mentioned problems. This paper introduces the design and performances as well as the evaluation of the mobile chair based on a human engineering point of view.
nteractive motion control gives the functionality to make the conventional motor control technology detect body intelligence. We evaluated about the assistant system of the electric wheelchair using this control. The experiment measured the torque and feedback frequency of the motor under various conditions. As a result, the assistant system was understood that it is effective to use interactive motion control.
On the basis of experimental investigation, the electrochemical properties of AB5 hydrogen storage alloys La0.54Ce0.28Pr0.18Ni4-xCo0.6Mn0.35Alx (x=0.1, 0.2, 0.3) using at -40°-25°C are discussed. The obtained results showed that the discharge capacity at different temperature, the high rate discharge property and the cycling life of the alloy electrode are in close relationship with the x value. When x increases from 0.1 to 0.3, the discharge capacities with discharge current density of 60mA/g are slightly decreased at 25 °C, evidently decreased at -40 °C, and the cycle life was slightly improved. And the element Al is detrimental to the high-rate property of AB5 alloy.
In this paper, Switched Reluctance Motor (SRM) for electric vehicle (EV) is designed using finite element method (FEM). The static torque of SRM is estimated with the magnetic field analysis. The temperature rise with time of SRM is estimated with the heat transfer analysis. First, the static torque and temperature rise with time of 600W SRM for sample machine are measured in the experiment, and they are compared with the calculated results using FEM under the same conditions. The validity of magnetic field analysis and heat transfer analysis is verified by the comparisons. Then, the 60 [kW] SRM for EV, which has the output characteristics equal to 1500 [cc] gasoline engine, is designed with the magnetic field analysis and heat transfer analysis.
This paper proposes the introduction of a small and light-weight electric vehicle named Economy-Running EV with a single-passenger operating at minimum power. Driving power source in the trial electric vehicle using a fuel cell with a 24V, 200W is aided by EDLC (Electric Double Layer Capacitor) with capacity of 5F instead of a battery. At present, running characteristics of Economy-Running EV using a brushless dc motor as the drive system measures the current and voltage supplied to it, there are investigates the supplying electric energies and accelerating speed at starting. As a result, the supplying electric energies and accelerating speed are improved about 5 times and 2 times, respectively.
This paper proposes the introduction of a small, light-weight and slow speed electric vehicle named Pipe EV with a single-passenger operating at minimum power. Driving power source in the trial electric vehicle using a fuel cell with a 24V, 300W is aided by hydrogen storage material filled-up to 1.5MPa instead of a battery. At present, running characteristics of Pipe EV using a DC motor as the drive system measures the current and voltage supplied to it, and investigates the mileage when that is run at a specific speed using a filled-up fuel cell. As a result, at a speed of 30 km/h, generating current and voltage of fuel cell are 7A and 16V, respectively. That is, generated output of fuel cell is 112W, and mileage is about 75mile (120km).
The behaviors of In3+ and activator were studied on Pb anode of lead-acid batteries. The deposition of In with high hydrogen overpotential during the potential scan deviates negatively the hydrogen evolution potential. The current in redox couple of Pb/PbSO4 is slightly decreased because of PbSO4 formation on Pb adsorbed with In. This is the important difference between In3+ and Ag+ added to 5M H2SO4. The activator is less adsorbable on bear Pb, and adsorbed easily on PbSO4 formed on Pb. The complex ions of In3+ and activator molecules are adsorbable on Pb, and PbSO4 is initially formed on the adsorbed layer of complex ion at the potential in redox couple of Pb/PbSO4.
This paper presents a generalized formulation to forecast the loads of Plug-in hybrid electric vehicles. With this method, utilities can implement customer-oriented pricing strategy to influence the load profiles and the amount of electricity demand. The pricing strategy increases customer satisfaction and produces desired changes in the utility's system load shape. The pricing strategy incorporates utilities and customer requirements into integrated planning procedures. A case study is conducted to illustrate the application of the load forecasting method.
The behaviors of Ag+ and activator were studied on Pb anode for lead-acid batteries. The deposition of Ag and dissolution of Ag+ take place at lower potential than redox couple of Pb/PbSO4. This process may be considered to activate the reaction in the redox couple of Pb/PbSO4. The activator molecules are less adsorbable on bear Pb, and adsorbed easily on PbSO4 formed on Pb. The complex ions of Ag+ and activator molecule are adsorbable on bear Pb, and PbSO4 is initially formed on the adsorbed layer of complex ions.
To develop new in-wheel-motor electric vehicle with compact chassis structure, using a double-wishbone suspension mechanism with zero toe-in fluctuation, a module structure composed of double-wishbone suspension with torsion bar, sensor, brake and in-wheel motor was presented, and a new method for analyzing and designing the stiffness and damping parameters of double-wishbone suspension with torsion bar was strictly derived. Then, the theoretical results above were successfully applied in the chassis development of new electric vehicles with four in-wheel motors, such as fuel cell mini-car with steer-by-wire, etc.
This study considers the possibilities of obtaining electric power from vibrational energy of an electric vehicle using a permanent magnetic linear power generator. A mover of the linear power generator can convert any mechanical vibration to electric power. A mover of the proposed linear power generator, which includes permanent magnets, is linearly driven through a stator by an external force, directly. Therefore, the generator can convert any mechanical vibrations into electrical power. Nd Fe-B magnets in the mover are placed so that the same magnetic poles face each other, in order to make the large change in magnetic flux in the coils of the stator. The coils are placed in the stator with the same interval as the magnets. Alternate coils connected in a series were wound in opposite directions to the next coil. The stator was covered with a magnetic material cover, so that the magnetic flux is extended through the cover and reduces cancellation of the flux in the coils of the stator. The pilot generator was produced on the basis of numerical simulation results derived from the distribution of the magnetic field, electromotive force and uniaxial stress. The produced linear power generator was put in an experimental apparatus that emulated the function of suspension in a car. The characteristics of the generator were measured by adding various mechanical vibrations to the experimental apparatus.