Alternative engines are normally classified as engines that do not use hydrocarbons for fuel. Alternative engines are normally more efficient and environmentally-friendly than conventional combustion engines, but are plagued by many problems. A bigger technical obstacle in producing alternative engines is not the engine itself, but an inability to store fuel effectively. Some of the more common alternative engines are now being worked into automobiles, but only in a limited basis so far.

Electric Engines

Electric engines are not all that uncommon; they can most often be found in urban areas, for reasons explained below. California is one such place where the use of electric cars is encouraged, as the government is attempting to reduce pollution, especially over Los Angeles.

Electric engines operate on the principles of electro-magnetism. An electric motor has several electromagnets placecd in a cylindrical pattern. Inside this cylinder is placed a normal magnet connected to a driveshaft. Electromagnets do not have defined north/south poles; the direction electric current flows through them determines the direction of the poles. The magnet sitting inside of this electromagnet cylinder, however, does have defined poles. So, alternating current is passed through the electromagnets, causing their poles to reverse every cycle.

Let's look at one cycle of an electric motor with four electromagnets in a circle with a bar magnet sitting inside of that circle. Power is turned on, and the electromagnets start to produce magnetic fields. The magnets on the left and top have north poles pointing in towards the center of the circle, while the right and bottom have south poles pointing inward. The central magnet then orients itself so that its north pole points towards the south poles of the electromagnets, and its south pole points towards the norths ¹. Just as it gets to its new position, however, the polarity of the electromagnets is reversed. Now the north pole of the central magnet is pointing towards another north pole, and the south pole is pointing towards a south. So, the central magnet continues spinning in order to have its poles line up with opposite poles. The polarity of the electromagnets keeps reversing, continually rotating the central magnet. Thus, the driveshaft is turned ².

Enough physics. More importantly, is, "Where can I, the environmentally conscious Guide Researcher, find a car with an electric motor in it?" Well, that may be more difficult than you may at first believe. Electric motors are not particularly powerful, which is one reason why they are not put in cars very frequently. Also, battery life for these cars is not very astounding: only about an hour or two of running time is what you can expect from a full charge. Then, the car must normally be charged overnight to completely refresh the batteries. The batteries themselves can be fairly expensive, and it takes a lot of them to power a car. The proceess of making the batteries is also a very dirty one, and some people believe the pollution made generating the electricity to power the car is the same amount as a normal combustion-powered car would make. Therefore, electric cars are often very light and compact. Couple this with the short battery life and you get a car that is really only useful for short commutes to work or the shopping center.

Several car manufacturers are finding a way to make a compromise, however. "Gas-electric hybrids" are currently on the design boards of many companies, and two models have already been marketed. These cars have a normal, albeit rather small,
internal-combustion engine, along with an electric "assist" motor. The assist motor gives that extra kick during acceleration,where fuel economy is lowest. During cruise the electric motor shuts off, and when braking the motor normally helps to charge the battery. This method boosts fuel efficiency dramatically, often reaching fuel economies of 60 mpg³ or more. As yet, however, the market for these cars has been relatively small. In an effort to create a market for these cars, Honda has been selling its Insight model at a loss to keep the car affordable.

Solar Engines

Solar engines are, in fact, electric engines that are powered by solar cells. Cars run by solar engines are rare indeed; in fact, the majority of people who drive solar cars are engineering students with too much time on their hands. Needless to say, solar cars have not been mass-produced yet.

Solar cells do not generate much electricity; for this reason, a huge array of cells must be used to power a car. In order to fit all of these cells on the car, the body must be relatively large to the load it can carry⁴. Also, to increase the efficiency of the engine, the car is made as lightweight and aerodynamic as possible. These design points reduce friction on the car and decrease the power necessary to get the car rolling. In addition, a solar car's performance is obviously decreased in any kind of cloudy weather, which limits its usefulness.

Fuel Cells

The Space Shuttle's rocket engines "burn" liquid hydrogen to give their thrust. While fuel cells do use hydrogen, nothing so dramatic occurs when fuel cells are in operation. Fuel cells react hydrogen and oxygen to produce power. The only product of this reaction is water vapor, which makes fuel cells zero-emmission engines.

Fuel cells are currently in the prototype stage for cars, but a different market is opening up for them: generators. In fact, the NASDAQ stock exchange has backup generators powered by fuel cells, and home generators are already in the works.

The problem with putting a fuel cell in a car is the storage of hydrogen. Liquid hydrogen is difficult to come by, and gaseous hydrogen would take up too much space to be practical. This Researcher has seen evidence of cars being fitted with fuel cells along with the standard combustion engine, but at the expense of filling the trunk of the car with a tank for the hydrogen. Fuel cells are still a future concept for automobiles.

Natural Gas Engines

Natural gas, also known as methane, is a hydrocarbon. Why, then, is this type of engine classified as an "alternative" engine? Quite simply, natural gas burns much cleaner than gasoline, diesel, oil, or coal.

Ignite your gas stove at home. Does it smell like your car's exhaust pipe? If it did, gas stove companies would be out of business. This lack of smell is evidence of a cleaner-burning fuel. Ideally, any hydrocarbon that burns should produce only carbon dioxide and water vapor. However, because of the additives in gasoline and the high operating temperatures of the engines, carbon monoxide and nitrogen oxides are also formed. Carbon monoxide is colorless, odorless, tasteless, and highly poisonous. Nitrogen oxides produce that lovely brown haze above major metropolitan areas and are causes of ozone depletion, in addition to also being poisonous.

Natural gas does not produce carbon monoxide or nitrogen oxides in any quantity near the amount internal-combustion engines produce them. Again, though, because the fuel is gaseous, it is difficult to store the fuel. Some rental companies actually rent natural gas cars, but finding a filling station will be a challenge. The cars are just too few in number to produce enough demand to build numerous natural gas filling stations.

Indifference

Despite all of the difficulties in producing alternative engines, the biggest obstacle by far is simply lack of demand. In this age of relative prosperity, gasoline prices are fairly low, internal-combustion engines are cheap to produce, and the average car owner can easily afford low gas mileages⁵. The idea of spending a little extra money to pay for something that will not perform as well as the current standard, but cause less environmental impact, is inconceivable to most of the population. Car manunfacturers will not produce alternative engines in cars because demand is so low. One of the reasons demand is low is because car manufacturers are not producing them... It is a vicious cycle, but one that must be broken by some forward-thinking individuals with the power to affect change.