Fuel Systems

The following are the fuel systems that we will be investigating over the course of our study.  Each of our group members will be specializing in one of these systems and has provided the general information outlined below.  The information provided on this page is to establish a common ground from which to begin this discussion.  From each general overview, we will be meticulously analyzing the impact which that system has compared to the others.  In the coming weeks, you should expect to see the findings that we unveil on this blog.

Gasoline:

In short, gasoline is the measuring stick which all other alternative sources are measured with.  Due to its simplicity and ease of use from a consumer prospective, gasoline has held a tight grip on the transportation industry for the past century.  Since it has been the focus of the industry for so long, the world has been evolving with the expectation of constant access to it.  Now, as the price of gas is rising, consumers are pressing for an alternative mode which will ease the burden—but this isn’t the first time this has happened.  In the 1970’s there was a similar fluctuation of interest in alternate fuel systems, so why hasn’t gasoline become obsolete?  Let’s take a look at how gasoline is rendered and used to help understand the situation.

Gasoline is a product of crude oil which comes from degraded biological material beneath the Earth’s surface.  Once pulled from the ground it goes through an intricate process to reach the proper flammability range needed for ignition within the engine.  To start, the crude is heated through a process called fractional distillation, wherein the various components are separated.  From distillation, the long, straight-chain hydrocarbons acquired are broken down by a catalyst and then reformed into branched groups.  The resulting compounds are combined with ethanol and other additives to create the various octane ratings available at a refueling station.  From the station the fuel is pumped into the storage tank of the vehicle which will imminently consume it.

Within the vehicle, gasoline undergoes the following steps to create propulsion:

1. The fuel is pulled from the storage tank
2. It is injected and compressed in a mixture with air inside the engine cylinder
1. Mixture is compressed by a piston in the cylinder
3. Spark plug arcs, igniting the mixture
4. The ignition yields a massive compression, which thrusts the piston back into the engine block
1. The engine block houses the crankshaft, which is spun by the ignition process
5. The result of all of the engine’s cylinders firing is the rotation of the vehicle’s transmission
1. The transmission increases the vehicle’s speed while decrease the engine’s
6. The transmission spins the driveshaft, which eventually spins the wheels
7. Finally the expended fuel mixture is expelled from the engine
1. The expelled mixture is referred to as the engine’s emissions

 The process of converting energy within an internal combustion engine is rather laborious, and takes a large toll on the components involved.  Throughout the life of an engine, it needs constant maintenance in order to prevent premature failure.  Typical maintenance will include, but is not limited to:

Table 1 - Subaru dealer maintenance schedule, illustrating gasoline engine upkeep.

Maintenance Mileage	Recommended Maintenance
3000	·         Replace engine oil ·         Replace engine filter ·         Verify all fluid levels
15000	·         engine tune up ·         Replace engine air filter ·         Verify engine belts ·         Verify drivetrain state
30000	·         Replace spark plugs ·         Replace PCV valve ·         Replace engine coolant ·         Inspect fuel lines and connections ·         Verify gear oils (differentials) ·         Inspect timing belt
60000	·         Replace fuel filter ·         Replace gear oils
105000	·         Replace timing belt

The maintenance items provided in Table 1 are those which are typical to the gasoline engine.  Other systems use similar processes in which they may require similar maintenance:  For example, a gasoline-electric hybrid also has a differential, so it too needs to have care given according to its own schedule.  

So this leads us to a point:  The gasoline system is not perfect.  That in mind, how will some of the leading alternative systems compare?  It is true that gasoline prices are rising significantly, but is it enough to warrant a complete overhaul of the transportation network?  Finally, what will it take to change the world’s state of mind, to adopt a new technology which may change or limit the way that we move around?  Over the next few weeks, this project will look for the answers to these questions.

Gasoline-Electric Hybrid:

             

Gasoline-electric hybrids have become a very common sight on American roads today.  Most of the largest car manufacturers are producing their own variation of the system, but all of them follow the same basic principles.  A hybrid system between gasoline and electric, is one which includes both a gasoline engine, and an electric motor network to propel the vehicle.  The most popular of these systems, which basically defined the hybrid industry, is Toyota’s Prius, which made its American debut in 2001.  The Prius uses a combined hybrid system, which means that the vehicle can be propelled by either the gasoline engine, or the electric motor.  Basically, the point of a hybrid vehicle is to reduce it’s dependency on gasoline, resulting in a reduced bill every month.

Due to the extra hardware used to create a gasoline-electric hybrid vehicle, they typically will cost more than the non-hybrid models.  Some of the additional pieces used to create the system include the motor, battery pack, control systems, regenerative braking systems, and others depending on the car.  There is very limited routine maintenance required to take care of the electric system, but the gasoline system requires a similar schedule as a typical gasoline powered car.  As far as the actual operation of the vehicle, there are about as many different programs as there are hybrid models!  From Toyota’s “Hybrid Synergy Drive”, to Ford’s “Hybrid”, each vehicle uses a slightly different program to accomplish the task.  Typically, a hybrid is either gas-electric all the time, or can be switched from full electric to gas-electric.

In a gasoline-electric hybrid system, the vehicle is still dependent on gasoline combustion, which means that most of the issues with a gasoline system are still present.  The main point of contention between them comes from the greatly improved fuel economy, which proves to be the primary selling point for most consumers.  Others find that reducing their emissions while operating their vehicle is more important.  If you were to ask most people about their opinion on hybrids, you would probably get one of three answers:  They don’t care; Hybrids will save the world; or Hybrids do more damage than good.  However, the point of this study is to realistically quantify not only the impact of the vehicles operation, but also the impact that the production and eventual disposal of the vehicle will have.  Only through further examination of each step of this system’s cycle, will we be able to conclude quantitatively whether hybrids are the way to go.

Electric:


New to the roads of America in the past few years has been the electric vehicle. First implemented in trial releases throughout California, the electric car has had many chances to shine and make a significant impact on the automobile scene here. The first attempts at releasing electric cars to the public quickly faded out of perspective. Now today, with the unveiling of cars such as the Nissan Leaf and the Tesla Roadster, everyday consumers have the option to buy a car that can be run strictly off of electricity. with their high mileage, it would seem very enticing to a consumer to purchase one of the many new electric cars available on the market today.
             
One of the main problems with the electric car that scares many potential customers is their relatively low range.  From just a hundred or so miles on a full charge, the electric car is limited to short commutes and regular day travel, but it is not suited for any type of long-haul journey that would lead it outside of a city (where the vast majority of the roadside charging stations are located) or far from the owners home. The plus side to this is that for the everyday worker who lives near the city and works nearby, he can drive to work and home without too much worry of losing power as long as he remembers to charge his car each night when he returns home.
              
Along with the promise of nearly free fueling of your car, electric car owners stand to receive rather hefty tax-subsides each year for buying their full electric car. With rising CAFE standards, the need for companies to issue more highly efficient vehicles is pushing many automakers to design and build more and more electric cars. In Europe, the electric car has already been widely implemented in the major cities, as commuters can easily make their short travels and charge up at the roadside stations that now line many European city streets. One reason why this is enabled in Europe, is their efficient tactics at creating electricity such as the many nuclear power plants in south western Europe along with the wide array of solar and wind technologies that European nations have implemented to help offset the high cost of fossil fuels.


The technology that was conceived for the electric car includes a battery array and the traction motors that turn your braking energy into energy that goes back into charging the batteries. Advances in these technologies are being made to make the electric car far more efficient than it currently is. From taking the same idea of capturing the energy from braking, and using that to utilize the energy that is wasted in the lost heat of the entire system and more equivalently in the turning and flexing of the car itself. Aside from these advances there is little left to make the electric car more superior than the other vehicle forms other than making the way in which we create our electricity exponentially more efficient.

Bio Fuels:


Within the past decade is where the biggest influx of bio-fuel technology has occurred. First starting with the creation of high efficiency bio-diesels that run in any diesel engine, to more recently where scientists are biologically engineering algae to grow and make their own bio-diesel. Though there is still much work to be done in this field, the opportunities to implement bio-fuels is vast to say the least. From fermenting lumber trimmings, to soybean oil, plant scraps, algae or corn; the industry has hundreds of sources from which to draw their fuel.
                  
The mechanical system of bio-fuel vehicles themselves are almost identical to that of diesel cars and trucks which are already widely used in the thousands of tractor trailers that drive across our nation every day and night. There would be very few changes necessary to implement bio fuels into the mainstream automobile industry. The only major conflict that arises from the bio-fuels is the issue of "food-for-fuel". Here many groups are concerned with or willingness to sacrifice land, water, and food resources to grow and burn the corn or soybeans that are readily used today to make our current bio-fuels. With the population of the world increasing daily, the need for food and water may soon outweigh our need for the fuel that we can derive from them. Though with the advances science is making in this field, who knows what may come of it in the near future.
               
The major plus side to implementing bio-fuels aside from the seamless transition that would ensue is the relatively low cost of the fuel. Farmers today can already turn waste vegetable oil from restaurants into usable bio-diesel without much trouble or cost at all, and the oil comes free to them from the restaurants. So for pennies to the gallon one can easily make their own bio-fuel today as long as you know the minor chemistry involved and have a diesel engine car in which you can use your fuel.


Hydrogen Fuel Cell:


The process through which a hydrogen fuel cell creates electricity can be considered to be the opposite of electrolysis, a reaction through which hydrogen can be captured.  By subjecting water to a potential difference, the Hydrogen and Oxygen atoms break apart forming the homogeneous gaseous phases of each.  In this reaction, electrical energy is applied resulting in a rise in chemical energy in the form of elevated enthalpy.  In the Hydrogen fuel cell, these two compounds are allowed to reform into water, generating the potential difference which the vehicle stores in it's battery.  This potential difference, or voltage, results from the drop in energy of the compounds as they pass through the fuel cell and combine with on another.  Figure 1 below shows an example of the chassis of a Hydrogen fuel cell vehicle.

Figure 1 - The Honda FCX Chassis

The process by which a Hydrogen fuel cell vehicle generates it's power is as follows:

1. Hydrogen is pumped into on board storage tanks
2. Hydrogen is released from the tanks into the fuel cell
3. Hydrogen and Oxygen combine generating voltage
4. Voltage is stored in vehicle's battery
5. Battery supplies necessary power to operate electric motors

As we can see from this process, barring the first three steps, these vehicles operate very similarly to an strictly electric one.  In this case however, rather then being attached to the power grid overnight, Hydrogen vehicles constantly generate the voltage they need to run.  Without the detriment of having greenhouse emissions, Hydrogen is also similar to gasoline in that it can be recharged in minutes, making it more plausible then grid-charged electric.  These facts make the Hydrogen system a viable contender for the gasoline replacement candidate. 
             
With such a high similarity between a Hydrogen vehicles and our recognized definition of what a car needs to be, what faults might hinder the progression of the industry to this technology?  For starters, the scale of retrofitting required to implement the system is massive.  At this point, Hydrogen powered cars are not readily available for consumer purchase, and as such, the refueling network has not been established.  Likewise, the scale of manufacturing of Hydrogen gas has not yet reached a point where it could sustain a large scale implementation. Additionally, like most new technologies, the theoretical cost of these vehicles are on the order of fancy Mercedes, making it a hard selling point for the average consumer.


In weighing the good with the bad of this technology, it seems as though it may turn out to be implausible to change the industry drastically enough to sustain it.  With hydrogen in particular, which demonstrates the highest efficiency of the fuel cell systems in production, the shear level of commitment required in order to make the transition will most likely keep this technology out of the mainstream.  But, this is not to say that other fuel cells, like specially rendered gasoline, will meet the same fate.  Observing lower efficiencies, gasoline fuel cells are still a less impactful method of powering a vehicle with the peripherals which are already in place to sustain the current network.