Scarica Car innovation and hybrid cars e più Appunti in PDF di Inglese solo su Docsity! Car innovations The car industry is constantly bringing us new technologies, whether it be for safety, environmental concerns, usefulness or simply for pure innovation. Electric cars are quickly gaining ground. An electric car has a set of batteries that provides electricity to an electric motor. The motor turns a transmission, and the transmission turns the wheels. Any vehicle that combines two or more sources of power that can directly or indirectly provide propulsion power is a hybrid. So-called renewables such as solar and wind energy, however, do not seem commercially viable yet and cannot compete with fossil fuels. One kilowatt of solar photovoltaic power costs at least five times the cost of oil power. Solar power is even less competitive against cheaper fossil fuels like coal and natural gas. A radically new technology – perhaps replacing the silicon in photovoltaic cells with polymers – will be needed to make solar cost effective. Wind and biomass are closer than solar to becoming competitive with fossil fuels, but their capacity to supply large amounts of energy is limited. How hybrid cars work The petrol-electric hybrid car is a cross between a petrol-powered car and an electric car. The engine in a hybrid car can be much smaller than the one in a conventional car and therefore more efficient. Most cars require a relatively big engine to produce enough power to accelerate the car quickly. Big engines are heavy, requiring a lot of energy every time they accelerate. Moreover, the displacement of their pistons is larger, so more fuel is required by each cylinder. In a small engine, on the contrary, the efficiency can be improved by using smaller, lighter parts, by reducing the number of cylinders and by operating the engine closer to its maximum load. Besides a smaller, more efficient engine, today's hybrids use many other tricks to increase fuel efficiency. A hybrid car can capture some of the energy you dissipate when you brake and store it in the battery to use later. It does this by using regenerative braking. That is, instead of just using the brakes to stop the car, the electric motor that drives the hybrid can also slow the car. In this way, the electric motor acts as a generator and charges the batteries while the car is slowing down. Hybrid cars do not need to rely on the petrol engine all of the time because they have an alternate power source – the electric motor and batteries. So they can sometimes turn off the petrol engine, for example when they stop at a red light. Finally, hybrid cars use special tyres that are both stiffer and inflated to a higher pressure than conventional tyres. The result is that they cause about half the drag of regular tyres.
