lecture 5

Question 1

What are the 4 principle steps of an LCA?

Answer 1

1. Goal and Scope
2. Life Cycle Inventory
3. Impact Assessment
4. Interpretation

Question 2

What does the goal in an LCA describe?

Answer 2

The most important choices which are often subjective.

Question 3

What does the scope in an LCA describe?

Answer 3

It sets the system boundaries, which describe what is taken into the assessment and what is left out

Question 4

What does the inventory analysis step consist of?

Answer 4

It is based on the scope and possible uses of LCA, it lists and quantifies the inputs and outputs of the processes at each stage in one life cycle

Question 5

What does the impact analysis step consist of?

Answer 5

Determines the environmental impact of each input and output identified in the inventory

Question 6

What does the improvement analysis step consist of?

Answer 6

Identifies what can be done to reduce environmental impacts by changes in product or process design
This is the key step for engineering design decisions

Question 7

What are the environmental impacts of automobiles?

Answer 7

Land use decisions (constructing roads and parking lots) and engineering design decisions that influence release of pollutants to the environment

Question 8

What 3 air pollutants are emitted from automobiles

Answer 8

1. Hydrocarbons (HC, aka VOCs)
2. NO (nitrogen oxide) gases
3. CO (carbon monoxide)

Question 9

What is the main source of CO and HC’s?

Answer 9

Incomplete combustion of fuel

Question 10

How are HC’s emitted?

Answer 10

They are emitted in the form of gasoline vapours from incomplete combustion of fuel, hot engines, from the venting of the engine crankcase and from the venting and refilling of fuel tanks

Question 11

How are nitrogen oxides formed?

Answer 11

During combustion by chemical reactions between nitrogen and oxygen in air that occur at high temperatures

Question 12

What 3 factors make actual on-road emissions generally higher than federal test cycle values?

Answer 12

1. Higher average speeds cause higher NO2 emissions
2. Improper maintenance or tampering with emission control systems leads to higher emissions
3. A clogged air filter or dirty spark plug can increase hydrocarbon and carbon monoxide emissions above their normal design limits

Question 13

True or false: Heavier vehicles do not consume more gasoline than a passenger car

Answer 13

False

Question 14

True or false: Heavier vehicles emit more CO2, HC and NO per mile of travel than a passenger car

Answer 14

True

Question 15

What are most motor vehicles worldwide powered by?

Answer 15

Gasoline or diesel

Question 16

What do petroleum and its derivative fuels consist mainly of?

Answer 16

Carbon and hydrogen compounds

Question 17

What happens to carbon every time fuel is burned?

Answer 17

Carbon is converted to CO2, the natural product of combustion

Question 18

True or false: Automobiles are a major source of lead emissions to the atmosphere

Answer 18

True

Question 19

Why do many countries around the world continue to use leaded gasoline?

Answer 19

Lower costs

Question 20

How are CFCs used in automobiles?

Answer 20

Automotive air conditioners

Question 21

How do CFCs in automobiles impact the environment?

Answer 21

They are associated with depletion of stratospheric ozone and enter the atmosphere via leaks in AC systems

Question 22

What are 4 possible methods to design cleaner cars?

Answer 22

1. Designing for energy efficiency and reducing fuel consumption
2. Understanding and aiming to reduce pollutant formation
3. Alternative fuels
4. Alternative vehicles

Question 23

How do electric vehicles differ from gasoline cars?

Answer 23

EV’s have a battery instead of a gasoline tank and an electric motor instead of an internal combustion engine

Question 24

What are PHEV’s?

Answer 24

Plug-in hybrid electric vehicles are a combination of gasoline and electric vehicles. They have a battery, electric motor, gasoline tank and internal combustion engine