Lecture # 6 Automobiles and the environment Environmental impacts Air pollution Automobiles are responsible for a tremendous amount of air pollution. - The main source of CO and hydrocarbons was Incomplete combustion of fuel. - Nitrogen oxides were formed during combustion Example 1:
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Automobiles and the environment
Automobiles are responsible for a tremendous
amount of air pollution.
- The main source of CO and hydrocarbons was
Incomplete combustion of fuel.
- Nitrogen oxides were formed during combustion
Calculate the percentage reduction in CO, HC, and NOx
Exhaust emissions from a new passenger car in 1997
Relative to an uncontrolled car in 1967.
Grams per mile
Quality impacts of automotive emissions continue to be of
concern, because of:
1- Increasing vehicle population
Continues to grow, more vehicles caused more emissions
2- increasing travel per vehicle
3- Departures from federal standards
2. Greenhouse Gas emissions
Annual CO2 emissions from cars. Estimate the total annual
Emissions of CO2 from gasoline-burning vehicles in the united
states in 1995. the density of gasoline is 739 g/L. the total gasoline
Consumption by motor vehicles was 455*109 liters/yr. we had 352 g CO2
Per 114 g of fuel burned.
Automobile solid waste, estimate the total quantities of
(a) recycled materials
(b) solid wastes from US passenger car retirements in 1995.
Based on 1995 data, assume that 95% of retired vehicles undergo recycling
and that 75% of each car’s total weight is recovered.
Use the average weight of 1985 vehicles to estimate the per-vehicle
Weight of cars retired in 1995
-the engine including all auxiliary system and standby losses.
-the drive-train includes transmission, gear and drive wheels
Calculate the power needed to maintain a speed of 25 m/s on a level
highway for a midsize car weighing 15000 N.
The vehicle has a cross-sectional area of 2 m2 and a drag coefficient of 0.5.
The coefficient of rolling friction is 0.02, and the density of air is 1.2 kg/m3
The car in previous example accelerates from rest to 25 m/s in 10 seconds
Calculate the average power required in the absence of air
Resistance and road friction.
1- Designing For Energy Efficiency
2- understanding pollutant formation
better fuel economy and lower emissions.
Small design changes such as improved valve stem seals prevent
lubrication from entering the combustion chamber and exiting the exhaust.
Moving the top piston ring higher on the piston helps reduce the
crevices that unburned fuel can "hide" in and reduces hydrocarbon emissions.
Improved cylinder bore geometry stability allows the piston rings to seal better
and prevents oil from entering the combustion chamber.
New fuel injectors give more consistent fuel spray patterns allowing for
more complete combustion of the fuel.
Bioethanol: - Bioethanol comes from plants and is a renewable resource.
- Local emissions are up to 70% lower than standard petrol or diesel cars
Biodiesel: - Biodiesel is a renewable fuel that is produced from the oil of crops
- It gives a 60% reduction in C0²
Hydrogen: - Hydrogen fuel is produced from either the breakdown of
a hydrocarbon source or by the electrolysis of water.
- Battery Power Electric Vehicles
Rechargeable batteries used in electric vehicles
include lead-acid, NiCd, nickel metal hydride,
lithium ion, Li-ion polymer
Electric vehicle in Malta
than most cars do and manages to emit less then half the
CO2 emissions than even the most efficient cars currently
for sale. The vehicle was designed at the Technical University of Berlin