In today's world, almost all transport mediums, electricity generation of most countries depend on petroleum products such as diesel, petrol or crude oil. In the last century, petroleum has played an important role in the social, economic and political spheres the world over. Petroleum is a limited resource which will end one day so research on maximizing the efficiency or discovering an alternate should be done soon. Predictably, auto manufacturers have come up with some new innovations, one being the introduction of the Hybrid Electrical Vehicle (HEV) to the global market.
Some vehicles are hybrid in nature even though we may not be aware of it. A mo-peddle motorbike (motor engine + peddle) is good example. It uses an internal combustion (IC) engine for power as well as peddles to run the drive chain of the bike. Some ships also take advantage of the wind-power available during their sails and use masts as well as engine power. Submarines are also hybrid and can be either diesel-electric or nuclear-electric.
Simply, HEV's are a combination of an internal combustion engine of a conventional vehicle with the battery and electric motor of an electric vehicle. Essentially, an HEV combines an energy storage system, a power unit and a vehicle propulsion system. The main options for energy storage include batteries, ultra capacitors and flywheels. Although batteries are by far the most common choice for energy storage, research is still being done on other energy storage areas.
Hybrid power unit options are spark ignition engines, compression ignition engines, gas turbines and fuel cells. As a result, HEV's can achieve unbelievable fuel economy rather than conventional vehicles. In combination, these attributes offer consumers the extended range and rapid refueling they expect from a conventional vehicle as well as much of the energy and environmental benefits of an electric vehicle. HEV's are inherently flexible so they can be used in a wide range of applications from personal transportation to commercial hauling.
Hybrid vehicles offer a further chance to reduce fuel consumption and emissions. Some vehicles are already in the market and many companies are working on different solutions. The chosen technology influences the overall result for actual operation because differences in efficiency and weight have to be considered. Also the vehicle investment cost depending on the chosen complexity should be taken into account.
Motivations for HEV's take place because the price of petroleum is a major issue for the world. HEV's are under discussion concerning fuel consumption benefit and therefore lower running costs. Higher manufacturing costs by HEV related components need to be considered. A hybrid car uses two distinct sources of power to drive the car. These are used to replace the usual heavy engine. Actually hybrids are strange for Sri Lankan society. Hybrid vehicles are rare on our roads with a few currently available because the price is not bearable for a developing country like Sri Lanka.
Alongside the IC engine, HEV's have battery packs that power a motor to drive the transmission of the vehicle. The IC engine and the electric motor operate in unison to provide the power which is comparable to the high power engine of a conventional car. These cars have an advanced computer-controlled electronics which determine when to use gasoline(petrol) engine power, when to employ the motor power and when to combine both of these power sources.
Nowadays there are two types of hybrid available in the markets, parallel and serial hybrid. In a parallel hybrid car, a battery-powered motor starts the car and drives it to the speed of up to around 25mph after which the petrol engine comes to the aid of the electric motor to provide the maximum power required in accelerating the vehicle on high speeds or when driving up steep hills. The petrol engine not only furnishes necessary power to the car but it also charges the battery. Therefore, a hybrid car battery is charged without requiring a separate electrical source.
Toyota Prius and Honda Insight are hybrid cars operating on parallel hybrid car technology. HEV also incorporates some of the advantages of a serial hybrid. In a serial hybrid car, it is the gasoline (petrol) engine that provides power to the generator which furnishes power to an electric motor to turn the transmission and hence turn the wheels of the car. It also provides charging to the battery. Therefore, the engine, the generator, motor, and transmission all operate in serial line.
The battery pack plays an important roll in HEV's. The performance depends on the storage capacity and the life time. Normally, the life time of the battery is designed to match the life time of the vehicle. Batteries are also ensured of being environment-friendly. Lead acid and Nickel-cadmium-based batteries are bad for the environment since they are more toxic than others. Unfortunately, most of today's cars use this type of batteries. Although more expensive, the toxic level of Lithium ion batteries are far lower comparatively with that newest technologies. Lithium secondary batteries consist of positive electrodes, made with lithium metal oxides, negative electrodes, made with carbon materials, electrolytes, composed of organic solvents and lithium salts, and separators.