Environmental Vehicles

By Seaswept

The main reasons for LEV’s or ZEV’s are:

• CO₂ is emitted in the combustion cycle. This is a greenhouse gas and so is contributing to the overall effect of global warming.
• General emissions cause smog in many inner-city areas and to overall poor air quality.
• Many of the chemicals present in the exhaust can cause lung diseases (asthma) and allergic reactions.
• Fossil fuels will run out!

The following is a list of pollutants caused by internal combustion engines:

Sulphur

• Can cause acid rain.
• Not really a problem with petrol and light fuels but with some diesels.

• Benzene emissions are considered to be carcinogenic.
• Some other HC's emitted cause irritation to the lungs and mucus glands and can cause asthma.

• Invisible gas is formed under poor combustion conditions, particularly in a shortage of air.
• Up to 7% of CO has been emitted by a car with the engine idling.

• These gases are released into the earth's atmosphere and can cause photochemical smog.

• The release of carbon dioxide is thought to cause global warming.

• 3 - Nitrobenzanthrones is released in this form and is thought to be the most toxic substance known. In the standard test for toxicity is caused 6 million mutations per nanomole. (The highest result ever!).
• Other particulates cause irritation of the lungs and mucus glands, and some are thought to be carcinogenic.

Zero emission vehicles

Nitrogen powered vehicles:
Nitrogen, the most abundant element in the earth's atmosphere, has a very low boiling point and so, when it is in the liquid state and stored in a controlled pressure environment at -196C, it contains a very large amount of potential energy. This liquid nitrogen is passed to a heat exchanger; here air is used to heat the nitrogen up to the ambient temperature. The nitrogen, now a high-pressure gas, is fed to a engine which works by converting high pressure into mechanical work. Washington University is currently working on the LN2000, which works on this principle. The University of Texas is developing another nitrogen powered vehicle project called the CoolN2Car. This car works on the same principle as the LN2000. One possible drawback of the nitrogen powered car is that energy must be used to compress the nitrogen.

Hydrogen Powered Vehicles:
The principle form of hydrogen powered vehicles is by the use of a fuel cell. This is done basically by hydrogen mixing with air and creating an electric current which, in turn is used to power the vehicle. Hydrogen is the most abundant gas in the universe, composing 30 percent of the mass of our sun and 90 percent of the universe. But it does not exist in a usable state here on earth. So, hydrogen is produced by extraction from water (H₂O), natural gas (methane CH₄), coal and petroleum. The main problem with using hydrogen to power a vehicle is the storage of because, the containers have to withstand very high pressure and have to be "crash resistant". The main bonus of using a fuel cell vehicle is the reduced emissions of CO₂, Sulphur, ozone gases etc. And also the near zero noise pollution.

Electric Powered Vehicles:
The principle of the electric powered car is simple: basically it contains huge rechargeable batteries which are used to power a motor and thus drive the car. Right now, electric cars are already being sold, so the concept is not new. Some electric cars are strictly electric and have short ranges and long charge times, while others are hybrid cars, where there is an electric motor to power the car and a petrol powered engine to recharge the batteries. There are major problems with electric cars:

1. The batteries can take over an hour to recharge
2. The batteries need to be replaced every so often, unlike the fuel cells in a hydrogen car
3. They have a very short range

Solar Powered Vehicles:
The solar powered car is basically the same as an electric car but, the battery is constantly (whilst in daylight) being topped up by the solar panel.

Natural Gas Vehicles:
As a fuel natural gas is one of the cleanest burning. Emissions from the combustion of natural gas (as opposed to petrol / diesel) in an internal combustion engine are very low. For example emissions of carbon monoxide are approximately 70 percent lower, non-methane organic gas emissions are 89 percent lower, and oxides of nitrogen emissions are 87 percent lower (compared to the combustion of petrol). Also the combustion of natural gas emits significantly lower amounts of greenhouse gases and toxins (including a decrease in the amount of suspected carcinogens found in particulate emissions). With all this in mind natural gas is one of the most viable alternatives to petrol / diesel but, it doesn't really help when it comes to the fact that fossil fuels are running out!

Boron Vehicles:
An unusual but valid idea with some real prospect, the boron powered car. The main reason for a car fuelled on boron is a safety reason. Boron is very combustible but very difficult to light. This is great for a car because, many accidents are made worse by the flammability of the fuel. The key to making boron burn is to ignite it in an atmosphere of pure oxygen. When pure boron and pure oxygen have no products but solid boron oxide. So there are no other emissions and no harmful pollutants - it is a real zero emission car! Also, at engine temperatures boron oxide is not solid, but like treacle, so is fairly easily transported, then once below 200C it is solid so, is easily disposable. An added bonus is that boron oxide is involatile so, excess oxygen can be used in the combustion process making a very efficient process. So, this is all very well but surely boron does not contain as much energy per gallon of petrol? So, you would think but strange as it may seem boron has a very high energy density.

Links and Resources:

Eco Cars Website:

http://www.ecocars.com/

Zero Emission website:

http://www.zevinfo.com/

Natural Gas Vehicle Coalition:

http://www.ngvc.org/ngv/ngvc.nsf

Info on the LN2000:

http://www.aa.washington.edu/AERP/CRYOCAR/CryoCar.htm

Another Nitrogen Powered car:

http://www.mtsc.unt.edu/CooLN2Car.html

The Toyota Prius 2003:

http://www.toyota.com/html/shop/vehicles/prius/

The Honda Civic Hybrid:

http://www.hondacars.com/models/model_overview.asp?
ModelName=Civic+Hybrid&bhcp=1&BrowserDetected=True

The Honda Insight:

http://www.hondacars.com/models/model_overview.asp?ModelName=Insight