Since we in industrialized nations are surrounded by cars, and often own them, we sometimes forget what marvels they are. They incorporate the latest technology into efficient, sleek packages that have been honed for the past 100 years. But even with all the changes that have taken place, the major parts of an automobile have remained essentially unchanged since Henry Ford's first Model T rolled off the line in 1908.
The frame of an automobile, sometimes called the chassis, provides a rigid platform upon which to mount everything else. It is also the first line of defense during an accident, absorbing the shock of the crash and directing it around passengers. Early frames were simple rectangles of welded steel girders. While this concept endures in some applications, most automobiles now have a unibody frame in which parts of the body are welded to the frame to enhance strength and rigidity. The body sits atop the frame and includes the roof, doors, hood, windows and body panels. The body also protects passengers, and keeps out exterior noise and the heat and cold. In recent years the body has become a principal feature of "green" technology, and designers have sought more aerodynamic designs to more efficiently cut through the wind.
The drive train is the heart and muscles of the automobile. It includes an engine that can burn fuel or might be electric. The transmission, a set of gears that allow the engine to operate in its most efficient range, is connected to the output shaft of the engine. Transmissions can be automatic or manual. In rear-wheel drive cars, the transmission is connected to the reduction gear via the drive shaft. The reduction gear determines the operating range of the vehicle. In front-wheel drive cars, the transmission is directly connected. Power is sent through a differential, a device that adjusts the speed of the wheels during turns so they work together. The final parts of the drive train are the wheels and tires, which transfer the power generated by the engine to the ground.
An automobile's control system is not just the steering wheel, accelerator pedal and brakes. The suspension is just as important. It is a series of levers and springs that permit the wheels to move independently of the frame. Without this, every bump would cause at least two tires to lose contact with the ground, creating danger. A well-tuned suspension allows wheels to absorb the energy of bumps while transmitting little motion to the body and the passengers. The suspension also improves handling during braking, accelerating and cornering. So not only is the suspension an important safety feature, it is also an important comfort feature.
A car wouldn't go far without an energy source and a way to get it to the engine, but most of us don't think about the energy in a tank of gasoline. It is equivalent to carrying around several boxes of dynamite in your trunk. But modern fuel systems, made with space-age plastics and metals and mounted between frame beams, greatly reduce the hazards. A bank of batteries in an electric car also can be considered a fuel system.
This system has changed more than any other since 1908. The first electrical systems consisted of little more than a generator to power the spark plugs and the lights. Advances in technology and the desire for greater convenience soon led to the addition of starter motors and batteries to start the car and generators (alternators) to keep the battery charged. Electric fans for heating, and later for cooling, and radios were not far behind. More recently, electrical systems have undergone a complete transformation. They are now called on to energize powerful computers that manage the engine for optimum performance and pollution control, and for such gadgets as GPS systems, in-car theaters and satellite radios.
The greatest changes in automobile technology over the next few years likely will be in the drive train and electrical system. With the growing use of hybrids and the promise of fuel cells, the simple car is likely to grow ever more complex.
