Vehicles that include electric drive motors have many advantages over the traditional vehicle. Lower noise and gas emissions are among the major benefits.
While other benefits include, fewer moving parts, less maintenance requirements and, increased reliability.
Power for the electric drive motor is obtained from either rechargeable storage batteries or a generator via an electrical inverter/converter.
The most popular types of electric motors used are brushless, multi-phase, synchronous and permanent magnet motors.
The meanings of these terms are:
- Brushless: Brushes and commutators are not used
- Multi-phase:The stator contains more than one winding, usually three
- Synchronous: The speed of the rotor is synchronized to the frequency of current flowing through the stator windings. This design maintains excellent power and efficiency characteristics even at low speeds
- Permanent Magnet:The rotor is made from very powerful rare earth permanent magnet alloys. Typically neodymium-iron-boron or samarium-cobalt.
Basic Operation
The computer controls the direction, frequency, order and amplitude of current flowing through the stator windings. The magnetic field produced by this current reacts with the permanent magnets of the rotor. This causes the rotor to rotate. It is important to note that these systems operate on dangerously high voltages typically 500 volts.
The electric motor is connected to road wheels via gears, chains, or shafts.
Vehicle braking and current flow back into the battery The electric motor can also be used as a generator to provide partial recharging of batteries whilst braking or during over-run.
Biodiesel
Biodiesel refers to a diesel-equivalent, processed fuel derived from biological sources. It's a processed fuel that can be readily used in diesel-engine vehicles, which distinguishes biodiesel from the straight vegetable oils (SVO) or waste vegetable oils (WVO) used as fuels in some modified diesel vehicles. Biodiesel is biodegradable and non-toxic, and has significantly fewer emissions than petroleum-based diesel when burned.
Biodiesel functions in current diesel engines and can be distributed using today's infrastructure, but is generally more expensive to purchase than petroleum diesel. Biodiesel will degrade natural rubber gaskets and hoses in vehicles (mostly found in vehicles manufactured before 1992, most likely already replaced with synthetic rubber which is not effected by biodiesel).
Biodiesel is a light to dark yellow liquid with a viscosity similar to petrodiesel (diesel produced from petroleum). It can be used as an additive in formulations of diesel to increase the lubricity of pure Ultra-Low Sulfur Diesel (ULSD) fuel, although care must be taken to ensure that the biodiesel used does not increase the sulfur content of the mixture above 15 ppm. Much of the world uses a system known as the "B" factor to state the amount of biodiesel in any fuel mix, in contrast to the "BA" or "E" system used for ethanol mixes. For example, fuel containing 20% biodiesel is labeled B20. Pure biodiesel is referred to as B100.
Biodiesel's higher lubricity index compared to petrodiesel is an advantage and can contribute to longer fuel injector life. Biodiesel is a better solvent than petrodiesel and has been known to break down deposits of residue in the fuel lines of vehicles that have previously been run on petroleum. Fuel filters may become clogged with particulates if a quick transition to pure biodiesel is made, as biodiesel “cleans” the engine in the process. It is, therefore, recommended to change the fuel filter within 600-800 miles after first switching to a biodiesel blend.
Biodiesel is water-soluble and attracts moisture, which may be introduced during processing or by condensation in the storage facility. Contamination by water can cause the following problems:
- The heat of combustion is reduced causing harder starting, less power, and more smoke.
- Corrosion of fuel system components - fuel pumps, injector pumps, and fuel lines etc.
- Water freezes to form ice crystals near 0°C (32°F). These crystals provide sites of nucleation and accelerate the gelling of the residual fuel.
- Water accelerates the growth of microbe colonies whih can plug up a fuel system. Pure biodiesel (B100) users who have heated fuel tanks therefore face a year-round microbe problem.
