What is a Hybrid Vehicle?
Future on wheels
Any vehicle combining two or more energy sources capable of providing propulsion power, either directly or indirectly, is a hybrid. A motorized bicycle is a sort of hybrid as it combines a gasoline-powered engine with the strength provided by the driver’s pedals. Most locomotives pulling trains are a diesel/electricity hybrid. Cities such as São Paulo have diesel and electric-powered buses. Those vehicles can draw electric energy from suspended cables (aerial network) or operate with a diesel motor-generator and batteries when not in the reach of the cables. The enormous mining trucks are a good example of diesel and electricity hybrids. Submarines are also hybrid, some are powered by electric-nuclear systems while others are by electric-diesel systems.
Technology developed by Eletra for hybrid trucks and buses
• The Hybrid Bus ELETRA may be compared to a trolleybus, but rather than seeking energy from an electric source, it generates its own onboard.
• The electric motor is responsible for the traction on the wheels and a motor-generator pack generates the power required to make the vehicle move. This motor-generator pack can be comprised of diesel, alcohol, gas, gasoline engines or any other fuel types. The engine operates under stationary conditions, whose function is to generate power.
• In order to increase the capacity to provide power to the electric motor, there is a battery pack, whose purpose is to store and provide energy whenever needed. Hence the denomination “Hybrid Bus”, as it has two energy sources: the motor-generator and the batteries.
• When the vehicle is started up, the Diesel Engine reaches the ideal “point” of rotation and will remain as such until the vehicle is turned off again. That is, it operates the whole time under constant rotation.
• For a Diesel Engine, the ‘ideal point’ is when it reaches the rotation considered to offer the best consumption and emission conditions. That is, when it consumes and emits less pollutant.
• During transit, the electric motor is fed by the set “motor-generator + battery pack”. When the vehicle stops to embark or disembark passengers, the motor-generator pack recharges the batteries.
• This arrangement allows the utilization of a much smaller Diesel Engine. For a conventional 12 meters diesel-powered bus it is used a 210HP engine, for its hybrid counterpart the engine is of 80HP.
• The whole process is done electronically, ensuring the perfect synchrony of the system.
• The vehicle has no gear transmission, braking is electric-based, the engine operates under ideal condition, acceleration is controlled and the whole system is electronic managed.
• Electronic management significantly reduces the operating cost of such vehicles, ensuring more agility in the maintenance and higher durability of components.
• Reduction in fuel consumption may reach 20% according to operation conditions and optimal use by the driver.
• The lifecycle of a hybrid bus is the same of a trolleybus: 20 years. It is worth reminding that in São Paulo some trolleybuses remain operational for up to 45 years.
• Hybrid buses reduce the emission of pollutants as the combustion engine is under fixed rotation, eliminating accelerations with sudden rotation changes, which is commonly seen in conventional diesel-powered buses.
• Data disclosed by the World Bank indicates that the emission of particulate material is the most hazardous pollutant for the health of a local population. With the use of hybrid buses to perform the urban transportation of passengers, the reduction in smoke emission can reach 90%.
• Benefits from this reduction are reflected in the habitants following a decrease of diseases such as heart, lung, allergic, among others. Studies show that even stress may be caused by poor air quality.
• Global scenario indicates that hybrid vehicles are the best solution to reduce to effects caused by pollution inside urban centers.
Advantages for the passenger:
• Hybrid buses are very comfortable for the user. Acceleration is electronically controlled and avoids the constant bumps from conventional buses.
• Diesel Engine is acoustically isolated at the vehicle rear, which decreases by up to 20 dB internal and external noises.
• The vehicle driver works with much more comfort, well-being and tranquility, which reflects in the interaction with passengers and when driving the vehicle.
• Reduction in the emission of pollutants directly affects the health of a whole community.