Primer on Automobile Fuel Efficiency and Emissions - Pollution Probe

CHAPTER 3 | INCREASING FUEL EFFICIENCY BY IMPROVING AUTOMOBILE TECHNOLOGY
AUTOMOBILE ENERGY USE, EFFICIENCY AND
Chapter two discussed how energy from fuel is converted into mechanical
energy to power an automobile, how that energy is distributed throughout
the automobile and where energy is lost along the way. By decreasing the loads on the vehicle (i.e., drag
due to air and rolling resistance, and inertia due to mass) and by decreasing the energy lost within the
system, the distance an automobile will travel on a tank of gas can be increased (i.e., improving fuel efficiency).
The less fuel consumed by an automobile, the lower the emissions of carbon dioxide -- a major
greenhouse gas. This chapter discusses in more detail the specific improvements that can be integrated
into new automobiles to improve fuel efficiency.
Decreasing Vehicle Weight
Weight is one of the most important factors governing an automobile’s fuel efficiency. The greater the mass of
the vehicle, the more inertia it has, and the more energy is required to accelerate the automobile (and more energy
is lost to braking). In contrast, lighter vehicles require less power to accelerate; this means smaller, less powerful
engines are able to provide the required acceleration performance without consuming as much fuel. Consider,
for example, how much easier it is to physically push a lighter vehicle; it may take only 1 or 2 people to get it
moving. However, a heavier vehicle may need 3 or 4 people. Short of reducing vehicle size, several options exist
to lower vehicle weight. Many automobile parts can be made of lighter materials. Conventional steel in automobile
parts can often be replaced with significantly lighter materials that incorporate high strength-low alloy
steels, aluminum, magnesium, titanium, carbon-fibre composites and plastics without compromising safety or
performance. In this way, some automobile manufacturers are aiming to cut vehicle weight by up to 40 per cent
<strong>Primer</strong> on Automobile Fuel Efficiency & Emissions
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