Most drivers know that they could be facing something serious when the dreaded check engine light flicks on. But do you really know why that light is there? Although at the time it may seem like a ploy by repair shops to dip into your wallet, check engine lights were established for an important reason. Check engine lights are actually designed to alert drivers to computer-monitored emissions problems as it is part of the vehicle's emission system. Now a standard feature in vehicles, check engine lights have become a valuable part of keeping emissions controlled. With so many vehicles on the road these days, it is essential that emissions are monitored and standards are followed to keep vehicles running smoothly and our environment healthier.
The New Year is the perfect time to learn about emissions and make a resolution to monitor your vehicle and have it serviced regularly to prevent any major problems. This feature of a "check-engine light" became standard in vehicles when automotive computers appeared in 1981. Federal law states that every new vehicle sold in the United States must have a check engine light. Vehicle computers use information signals from sensors to produce control signals for fuel, spark delivery, transmission shifting, and other important performance functions. The car's computer always monitors the input signals that could affect emissions overall. If any of the signals exceed the government standards, the computer turns on the check engine light.
Before the Industrial Revolution, levels of toxic chemicals in the air were sparse, but increased fossil-fuel production and use by vehicles and engines decreased air quality. Then, there were thousands of cars more seen on the road in the years after World War II which in turn intensified the spread of air pollution, added more and newer (and more serious) sources of pollutants, and almost immediately posed a threat to many major cities. Vehicle emissions became an increasingly important topic of discussion in the 1970's. According to the Environmental Protection Agency (EPA), vehicle emissions are defined as pollution from cars in the form of by-products from the combustion process (exhaust) and the evaporation of fuel itself. Although emissions from single vehicles are low, when you put together all of the cars on the roads, especially in large cities, the personal automobile is the single greatest computer and it really adds up. It may not seem like you are "polluting" as you drive your own car, but burning the fuel in your engine combined with millions of other engines have potentially dangerous effects.
Gasoline and diesel fuels are a mix of hydrocarbons (compounds which contain carbon and hydrogen atoms). If you had a perfect engine, oxygen would change all of the hydrogen in your fuel to water, as well as all carbon to carbon dioxide. The nitrogen in our air would not be affected. But the combustion process is far from perfect, and unfortunately our vehicle's engine emits many different types of pollutants. Some of these pollutants include hydrocarbons (when fuel molecules do not burn completely becoming a major component of smog), nitrogen oxides (contribute to acid rain and ozone), carbon monoxide (reduces the flow of oxygen in the bloodstream), and carbon dioxide (may not directly impact human health but potentially harmful for global warming).
Beyond just exhaust emissions are evaporative emissions. These hydrocarbon pollutants tend to escape into the air outside through fuel evaporation. Today, we have efficient exhaust emission controls and gasoline is formed differently. Evaporative emissions account for the majority of hydrocarbon pollution and can occur in several ways; diurnal (gas evaporation increases as the temperature rises during the day because the fuel tank heats up and gas vapors vent), running losses (a hot engine and exhaust system can turn gas to vapor when left running), hot soak (a hot engine even after parked can give off gas vapors), and refueling (gas vapors can be forced out when you fill your gas tank with liquid fuel).
By 1966, motor vehicles contributed more than 60 percent of the pollutants in the atmosphere throughout the nation. So if gas and fuel emissions are so bad and happen so frequently, you may ask what has been done to control and limit them? Well, in 1970, The Clean Air Act gave the EPA top authority to regulate motor vehicle pollution and the EPA's policies on emission have become stricter since the early 1970's. These standards state how much pollution your vehicle is allowed to emit while automakers actually decide how to get the vehicle to follow these emission limits. Manufacturers were able to reduce emissions in the 1970's on the basis of improving engine design and the addition of charcoal canisters to collect vapors. Over the years, there have been major milestones to accomplish reduced emissions. For example, in 1975, catalytic converters significantly reduced hydrocarbon and carbon monoxide emissions. Another major feat was in 1981 with vehicle emission control technology. New cars at the time were being equipped with monitoring systems and computers which paved the way to what our vehicles are now. In 1990, more provisions were added to the Clean Air Act. These included more stringent tailpipe standards, increased strength and durable parts, and computerized diagnostic systems which even today identify emissions problems.
Still today, our personal vehicles account for 40% of all U.S. oil consumption and 19% of all U.S. carbon emissions. In his first term, President George Bush proposed $1.2 billion in research funding for hydrogen-powered automobiles to help lower emissions and help create a cleaner environment. Human health can be in danger when it comes to high vehicle emissions. Exhaust fumes contain a variety of chemicals and emissions. Exhaust emissions can be breathed in and transported into the bloodstream to all of the body's major organs. The most obvious health impact of car emissions is on the respiratory system causing asthma, acute bronchitis and other respiratory (breathing) diseases. Likewise, most emissions pollutants create harmful effects on the blood and circulatory system as well as the central nervous system. Worried yet? Experts state that "toxic chemicals may also stimulate the immune system to attack the body's own tissues, in particular the cells that line human blood vessels. The damage is minimal at first glance, but it can build up with consistent exposure to toxic substances which can eventually lead to blockage of the blood vessels, seriously increasing the risk of high blood pressure and heart disease."
This, too, is the goal of the Arizona Department of Environmental Quality (ADEQ). As vehicle use increases in the urban areas like Tucson and Phoenix, so does the emissions in the atmosphere. The air pollution poses a threat to human health and so to improve air quality and reduce vehicle emissions, ADEQ administers a mandatory vehicle emissions testing and repair program called "Vehicle Emissions Inspection Program (VEIP). VEIP emphasizes the importance of maintaining vehicle performance to lower emissions and extend the life of one of your most valuable assets - your car. VEIP uses new testing technology and customer service measures that increase the effectiveness of emissions testing and shorten the time customers spend in the emissions process. The results are cleaner air, faster testing procedures and better customer service," according to their website.
What happens if you fail emissions testing? In an effort to improve and protect air quality, it is important to know about testing and performance issues. Failing emissions testing and exceeding regulations forces drivers to make repairs that might otherwise be ignored. This is dangerous for the atmosphere, the vehicle, and the driver. To get everyone on board, all new trucks built between 1981 and 1995 had a 5-year, 50,000 mile federal emissions warranty. This warranty covered all emissions control parts and the fuel delivery system, with the exception of the pump, filter, and spark plugs. It also included the engine management system. In 1995, however, the federal emissions warranty guidelines changed and was extended to 8-year, 80,000 miles on the powertrain control module, but was shortened on everything else. Once the warranty has passed, the owner of the vehicle is responsible for emission repairs. There are provisions, waivers, and exceptions just as with anything else.
The EPA has previously published some fact sheets for drivers, such as "Your Car and Clean Air: What YOU Can Do to Reduce Pollution." The agency advocates some simple and easy changes to driving habits like avoiding unnecessary driving by consolidating trips, telecommuting, carpooling, using public transit, and choosing clean transportation alternatives such as biking and walking. They also suggest that you maintain your car properly. This will not only reduce the car's emissions and enhance its performance but will extend its life, increase its resale value, and optimize its fuel economy!
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