Technology Questions Chapter 9

Technology
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Question 6: How do emissions differ in spark ignition and compression ignition engines?
Sparks ignitions uses a spark to ignite the compressed fuel and air mixture. It uses gasoline and natural gas. On the other hand, Compression ignition engines compress air to a higher pressure and so it heats the air to the ignition temperature of the fuel that is then injected. A compression ignition engine contains a higher efficiency than the spark ignition engines due to the compression ratio used in the compression engines. Compression ignition engines uses diesel fuel and oil (Thad, 2003).
Question 9: What is an equivalence ratio? What is its relationship to pollutant emissions?
The equivalence ratio of a system is the ratio of the fuel to the ratio of the oxidizer in line with the stoichiometric fuel to oxidizer ratio. Equivalence ratio has a direct relationship with the pollutant emission because the pollutant emissions concentrations are always given as functions of both flam temperature and equivalence ratio (Thad, 2003).
Question 13: Describe the principle of exhaust gas recirculation and the pollutant that it controls.
It uses one basic principle of mixing fuel and air compressing the fuel inside the cylinders igniting it with a sparks plugs. It follows this principle for gasoline burns oxygen but air has a combination of other gases such as nitrogen. However, nitrogen is inert and does not mix with gasoline. Therefore, while the temperature in the combustion chamber rises nitrogen combines with oxygen and nitrous oxides (Nox) and Nox is the leading component of air pollution in urban areas. It lowers combustion chamber temperature reducing pollution and improving the fuel economy. The lowering of combustion chambers can be decreased by the exhaust gas recirculation using two methods. One by reducing the compression ratio, which is the sum of compressing prov...