From the first moment you step into a hybrid car, you will notice that a multitude of things are vastly different than your conventional vehicle. Turn the ignition key, and you will notice just how quiet these things are. For example, if you happen to be sitting in a Toyata Prius the car's electric generator will quietly fire up the conventional internal combustion engine, or "ICE". As the ICE comes up to operating temperature it will automatically be shut off, which brings the car's electric motor completely online. The gasoline engine will remain in a dormant state until it is further needed.
The Toyata Prius will remain completely in electric mode as long as speeds fall under the 15 M.P.H. limit. As long as you don't exceed that speed, you are driving an entirely electric powered vehicle which is using absolutely no gasoline, nor releasing any harmful emissions from its exhaust system. Obviously, if you drive a bit more aggressively, or exceed 15 M.P.H. the ICE will again come online to produce the necessary, additional power required. A computer is constantly calculating the power requirements and sending this data to a device called a power split, which connects the electric and gasoline engines through a series of gears.
Things work slightly differently if you happen to be in a Honda Insight. The gasoline engines in these vehicles remain online from first start until they reach operating temperature, and come to a first stop. The ICE will become completely dormant at that point. As soon as you remove your foot from the brake pedal, shift into gear, or depress the accelerator the combustion will again come online to provide additional power as required. The variety of available transmissions in the Honda line of vehicles has made it necessary to utilize a bit more elaborate system of engaging and disengaging the electric motors. The dash panel will keep you constantly informed of the amount of electrical assist that is being provided. All the while a computer is in the background calculating how much power is required, and allowing the electrical assist to occur. This type of system allows for near conventional car performance, while achieving much greater fuel economy.
The nickel metal hybrid battery systems in these vehicles are quite fascinating. Again, a computer is constantly making calculations, sending power from the batteries to the electric motors when required. When the vehicle is in braking mode the electric motor begins to act as a generator, supplying the batteries with their needed charge. The computer is constantly monitoring the amount of charge in the batteries and maintaining a 30% - 80% charge at all times. These minimum and maximum levels are what allow these batteries to last in excess of 200,000 miles. That's a quite impressive lifecycle for battery technology, and a great thing as hybrid car batteries are quite expensive.
While this is a very simplistic overview of a very complex system, it does give you a basic understanding of the inner workings of the hybrid cars of today, and will hopefully be of assistance as you continue your quest of buying a hybrid car.
Thomas Manning is a highly experienced automotive technician and author, who frequently contributes to the hybrid cars information website Hybrid-Rides.com.