Charotar Institute of TechnologyCharotar University Of Science & Technology

•Demand for automobiles is rising worldwide.

•So is concern about greenhouse gas emissions. In response, scientists and engineers are working diligently to perfect new power plants for future vehicles, including battery and hydrogen fuel-cell electric cars.

•Although these and other alternatives show great promise for the long term, perhaps the single greatest way to reduce fossil-fuel consumption in the near term is to further improve today’s dominant transportation power plant: the gasoline internal-combustion (IC) engine.

•Fortunately, efficiency can be raised in a number of ways, notably, better control over the air-fuel mixture entering the combustion chamber, over the way gasoline is ignited there, and over the mechanical systems that harness that energy.

•These can improve traditional automobiles as well as gasoline-electric hybrid models.

•The most efficient gasoline spark ignition engines in mass-produced automobiles today convert only 20 to 25 percent of the fuel’s chemical energy into work. A modern diesel or gasoline-electric hybrid power train can reach 25 to 35 percent, but at substantially higher cost.

•In contrast, hydrogen fuel-cell electric cars—such as Honda’s FCX Clarity, now in limitedproduction—convert about 60 percent of the energyin gaseous hydrogen into motive power.

Despite the IC engine’s reputation

as old

and outmoded technology, however,

it continues to improve……

Today’s vehicles convert upto 25 percent of gasoline’schemical energy into work(purple and yellow). The restis lost. But technologies canreduce the waste (table).

For competitive reasons, automobile

manufacturers do not typically reveal

their own estim

ates of a future

technology’s potential

costs and

benefits.

Hybrid cars save fuel in part by turning off the engine when the vehicle is stopped, coasting or braking; batteries alone provide power.

A purely gasoline engine could do the same.

It would need a powerful starter that instantly turns the engine back on under any condition, which would likely require a 42-volt electrical system and battery, more robust than the 12-volt systems in vehicles today.

A start-stop feature could raise fuel economy by up to 7.5 percent