What Is A Hydrogen Engine?

There has been a push in this country toward using alternative fuels – specifically hydrogen fuels that are required to run on hydrogen fuel cells. So what is a hydrogen fuel cell? The explanation can be easy or it can be complicated. We’ll try to make it easy!

A fuel cell is an electrochemical energy conversion device. A fuel cell converts the chemicals hydrogen and oxygen into water, and in the process it produces electricity. The other electrochemical device that we are all familiar with is the battery. A battery has all of its chemicals stored inside, and it converts those chemicals into electricity too. This means that a battery eventually "goes dead" and you either throw it away or recharge it.

With a fuel cell, chemicals constantly flow into the cell so it never goes dead -- as long as there is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen and oxygen as the chemicals. The biggest advantage to a hydrogen fuel cell is that the only thing it emits when used as a fuel is water vapor.

You cannot ask the question “What is a hydrogen engine?” without considering the types of fuel cells that have been produced. The main type of hydrogen fuel cell is the polymer exchange membrane fuel cell (PEMFC). This is the fuel cell that the Department of Energy is focusing on as the next big thing because it is the most likely candidate for transportation applications.

The PEMFC has a high power density and a relatively low operating temperature (ranging from 60 to 80 degrees Celsius, or 140 to 176 degrees Fahrenheit). The low operating temperature means that it doesn't take very long for the fuel cell to warm up and begin generating electricity.

There is another type of hydrogen fuel cell that shows promise when trying to operate a vehicle. This one is the direct methanol fuel cell (DMFC). Methanol fuel cells are comparable to a PEMFC in regards to operating temperature, but are not as efficient. Also, the DMFC requires a relatively large amount of platinum to act as a catalyst, which makes these fuel cells expensive.
What is a hydrogen fuel cell? It is the next new wave of emerging technology in the field of alternative fuels that will help our country as well as our environment. A hydrogen fuel cell vehicle burns clean and runs efficiently. It is what alternative fuel supporters have hoped for since the advent of alternative fuels for energy – a clean vehicle that runs great and has safe emissions.

Disadvantages of Hydrogen Fuel Engines

The alternative fuel lobby will say that using hydrogen fuel cells to power your vehicle is definitely the way to go, but what about the disadvantages? They give us all the information about the advantages to switching to hydrogen fuel cells, but they gloss over the disadvantages. The truth is that while hydrogen fuel cells are highly advantageous, but they also have some significant disadvantages.

People who have studied hydrogen fuel cells say that there are three main disadvantages to using hydrogen as a fuel source.

1. The low density. A hydrogen fuel tank will have three times the size of a gasoline tank. Also it must be insulated, and this will add to its bulk. This seems entirely bearable.

2. Safety problems. Liquid hydrogen is cold enough to freeze air, and accidents have occurred from pressure build-up following plugged valves. Some say these problems can't be overcome, but many side with those who think they can be overcome.

In a collision the hydrogen tank may rupture, as can a gasoline tank. Limited accident experience suggests that the danger is somewhat less with hydrogen than with gasoline, because the hydrogen dissipates rapidly. The release of hydrogen into a confined space like a garage risks an explosion.

3. Since the insulation can't be perfect, the hydrogen will gradually evaporate, typically 1.7 percent per day. This is too fast for a car to sit for months between uses. A tank of compressed hydrogen holding enough to get to a hydrogen station would solve this.

If the engine is flexible enough to burn gasoline as well as hydrogen, a half gallon gasoline tank would suffice. Some automobile companies like BMW, have experimented with vehicles powered by liquid hydrogen. However, hydrogen cannot come into common use until the political obstacles to nuclear expansion are overcome or the technological obstacles to large scale solar energy are overcome.

It is unlikely to be used as long as gasoline remains so cheap – in other words as long as oil remains cheap and fear of global warming does not prevent its use. Hydrogen enthusiasts will just have to wait if this persists.

There’s really no doubt that using hydrogen fuel cells as an alternative fuel can be very advantageous both for the environment as well as for America in general by reducing our dependence on foreign oil. But there still are significant disadvantages that must be overcome before we can realize the real benefits of using hydrogen fuel cells as our main source of energy to power our vehicles.