Vehicle Fuel Efficiency, Improving Fuel Economy And

7/30/2019 Vehicle Fuel Efficiency, Improving Fuel Economy And

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Vehicle Fuel Efficiency, Improving Fuel

Economy and Engine Performance to

reduce Environmental Impact

Hafiz Mumtaz Alam

08-MS-EM-07


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Fuel efficiency of vehicles

1. Fuel consumption is the amount of fuel used per

unit distance; for example, liters per

100 Kilometers(L/100 km). In this case,the lower the value, the more economic a

vehicle is.

2. Fuel economy is the distance travelled per unitvolume of fuel used; for example, kilometers per

liter (km/L) or miles per gallon (MPG). In this

case, the higher the value, the more economic a

vehicle is .


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Fuel economy and fuel consumption are reciprocal quantities.

To convert between L/100 km and miles per US Gallon, divide

235 by the number in question.


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In Europe, the following are the standard measuring cycles for

"litre/100 km" value :

Urban Fuel Economy

Extra urban Fuel Economy

Overall fuel economy (complete cycle)

CO2 emission (complete cycle)


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Urban" traffic with speeds up to 50 km/h from

a cold start (first 800 seconds)

Extra urban" travel at various speeds up to

120 km/h which follows the urban test (800 to1200s)


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The following parameters are also generally

measured to validate the compliance

to European emission standards:

1.Carbon monoxide

2.Unburnt hydrocarbons

3.Nitrogen oxides

4.Particulate matter


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Test Procedure

The cycle must be performed on a cold vehicle at 20C (68F).

The cycles may be performed on a flat road, in the absence of

wind.

However, to improve repeatability, they are generally

performed on a roller test bench.

This type of bench is equipped with an electrical machine to

emulate resistance due to aerodynamic drag and

vehicle mass (inertia).


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For each vehicle configuration, a look-up table is applied, each

speed corresponds to a certain value of resistance

(reverse torque applied to the drive wheels).

This arrangement enables the use of a single physical vehicle to

test all vehicle body styles (Sedan, hatchback, MPV...) by simply

changing the look-up table.

A fan is coupled to the roller bench to provide the vehicle air

intakes with an airflow matching the current speed.


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Roller test bench with a

power of 300 kw


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Engine Performance and Fuel

Economy

Maintenance

Minimizing mass and improving aerodynamics

Efficient speeds

Choice of gear (manual transmissions

Acceleration and deceleration (braking)

Fuel type


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The energy in fuel consumed in driving is lost in many ways,

including engine inefficiency, aerodynamic drag, rolling

friction, and kinetic energy lost to braking

Driver behavior can influence all of these.

The city mileage of conventional cars is lower than highwaymileage due to: 1) a high proportion of idling time, 2) a low

proportion of time in the most-efficient speed zone, and 3)

more frequent braking.


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We can increase engine performance by

increasing fuel economy and decreasing fuel

consumption

Since CO2 emissions are directly proportional to

fuel consumption, So we can control these

emissions by having better fuel consumption ofa vehicle.


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Vehicle efficiency and

Environmental Impact Fuel efficiency directly affects emissions causing

pollution and potentially leading to climate

change by affecting the amount of fuel used.

It also depends on the fuel source used to drive

the vehicle concerned.

Cars can, for example, run on a number of fuel

types other than gasoline, such as natural

gas, LPG or bio fuel or electricity which creates

various quantities of atmospheric pollution.


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A related measure of fuel efficiency is the amount of carbon

dioxide produced as a result of the combustion process,

typically measured in grams of CO2 per kilometer (CO2 g/km).

A petrol (gasoline) engine will produce around 2.32 kg of

carbon dioxide for each liter of petrol consumed (19.4 lb/gal).

A typical diesel engine produces 2.66 kg/L (22.23 lb/gal)

Since the CO2 emissions are relatively constant per liter, they

are proportional to fuel consumption. The more fuel a car

burns, the more CO2 it emits.


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There is also a growing movement of drivers who

practice ways to increase their MPG and save

fuel through driving techniques.

They are often referred to as hypermilers.

Hypermilers have broken records of fuel

efficiency, averaging 109 miles per gallon.

Advances in engine and vehicle technology

continually reduce the toxicity of exhaust leaving

the engine. Therefore, technologies to detoxify

the exhaust are an essential part of emissions

control.


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Emissions Control Techniques

Air injection

Exhaust gas recirculation

Catalytic converters


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Vehicle Fuel Efficiency, Improving Fuel Economy And