There is a partial answer to this conundrum available today in the form of an innovative technology that uses existing fuel supplies more efficiently. This promising technology combines a gasoline engine with an electric motor to stretch a gallon of gas further than ever before possible. The vehicles that use this technology are called Hybrids because they use a combination of a very efficient gasoline engine and a hi-tech electric motor to propel the vehicle.
Despite the fact that they use electric motors that draw their power from a battery, hybrid vehicles do not have to be plugged in to recharge... Ever. The battery is recharged from two sources, and herein lies this system's advantage. The first source is from a generator powered by the internal combustion engine. The second source is through reclaiming the energy that is normally wasted slowing and stopping the vehicle. Let's look at the second method first because that is the most intriguing.
When you step on the brakes to slow a vehicle, you are counteracting the energy of a one or two ton projectile that wants to keep going because of inertia. In order to slow the vehicle, you must convert the energy of inertia into a different form: heat. The brakes heat up, absorbing the energy of the speeding vehicle, and the air that is directed around them then dissipates the heat, carrying it into the surroundings.
Many of us complain about how much it costs to heat a house, but here we are throwing all of our braking energy to the wind. What if we could capture some of that energy and use it later on to propel the vehicle? Well, that is exactly what a hybrid vehicle does. It uses a property that is inherent in all electric motors: the fact that electric motors and generators are exactly the same. If you send electricity through wires into a motor, it will cause the shaft of the motor to turn, but if you find another way to turn the shaft of an electric motor, it will generate electricity back through those wires.
The more work that a motor has to perform, the more electricity it requires. In the same way, the more electrical power you demand of a generator, the harder it is to turn the shaft. So, if we set the system up so that when you first step on the brakes, it connects this motor/generator to the battery in order to charge it, the effect will be to slow the vehicle down and, voila, we have free energy that we just stored in the battery to be used later to propel the car.
On the other side of the equation, the gasoline engine can be smaller because, when it needs extra power, the electric motor is there to assist in the acceleration using the free energy in the battery that was captured the last time that the brakes were applied. Because the engine doesn't have to be as powerful, it can be more compact and deliver much better gas mileage.
Car and Truck Power System
Gasoline internal-combustion engines power most automobiles, but some engines use diesel fuel, electricity, natural gas, solar energy, or fuels derived from methanol (wood alcohol) and ethanol (grain alcohol).
Most gasoline engines work in the following way: Turning the ignition key operates a switch that sends electricity from a battery to a starter motor. The starter motor turns a disk known as a flywheel, which in turn causes the engine’s crankshaft to revolve. The rotating crankshaft causes pistons, which are solid cylinders that fit snugly inside the engine’s hollow cylinders, to move up and down. Fuel-injection systems or, in older cars, a carburetor deliver fuel vapor from the gas tank to the engine cylinders.
The pistons compress the vapor inside the cylinders. An electric current flows through a spark plug to ignite the vapor. The fuel mixture explodes, or combusts, creating hot expanding gases that push the pistons down the cylinders and cause the crankshaft to rotate. The crankshaft is now rotating via the up-and-down motion of the pistons, permitting the starter motor to disengage from the flywheel.