Nowadays hybrid cars are cool both fashion wise and environmental. Hybrid cars are supposed to be better for the environment as they consume less gas and thus emit less green gases. They are also cool and fun as the green movement became young generation hip fashion. But there is also technology behind hybrid and we will explain a bit of it here.
Hybrid cars are exactly as their name suggests: a hybrid between two types of engines gas and electrical. The concept behind the hybrid car is simple: gas engine are efficient when the car moves at constant cruising speed. We all know this fact instinctively as for example cars get more miles per gallon on the freeway than in the city. The hybrid car adds an electrical engine that kicks in and helps the gas based engine where the gas engine is inefficient for example accelerating in city traffic.
Gas engines run on fuel. Electrical engines run on electricity. The electric engine in the hybrid car gets its electricity from batteries. The batteries in return are charged by the gas engine. In order not to waste fuel running the gas engine just for charging the battery the hybrid car takes advantages of wasted gas engine cycles in order to recharge the battery. For example when cruising on the highway the engine has residual energy that can be directed into charging the battery.
Another way to charge the batteries is by accumulating breaking energy. When you step on the brake and slow down the car the car energy is reduced. Energy does not just disappear and with normal gas based cars the movement energy that is lost is converted to heat generated in the braking system. Electrical car turn that energy into electricity accumulated in the batteries. When you brake a hybrid car the car converts its movement energy to electrical energy saved in the battery instead of to heat.
Another way to think about hybrid car is that they basically turn city driving into highway driving as far as gas efficiency is concerned. City driving is not efficient because of the constant bumper to bumper stopping and accelerating. A hybrid car uses the electrical engine to accelerate in the city and the gas engine only kicks in when higher speeds are needed or when the battery is too weak to provide the requested acceleration. Thinking about it the breaking energy is kept in the battery and is then used to accelerate the car. If you are familiar with electronics one way to describe a hybrid car is as if a big capacitor was added to the system and it filtered a stop and accelerate movement to a continuous movement.
Hybrid cars are not perfect. There are human factors that need to be taken into consideration. For example electric engine are completely silent which can confused the driver not knowing if the engine is on or not and can also be dangerous to pedestrians not hearing a coming car. Drivers thinking that hybrid cars are green or even good for the environment might drive more than they would have with a gas car thus after all sending the same or even more green house gas into the atmosphere.