The most economical car is the car that can travel the greatest distance
in miles on 1 gallon of fuel ie. the car that returns the greatest mpg (miles
per gallon). When talking about miles per gallon we need to know which gallon
is being referred to - the U.S. or the imperial gallon. The imperial gallon
is about 20% bigger than its U.S. equivalent. We also need to know whether
the car was being driven in the city or on the highway as highway driving
almost always returns higher mpg ratings. The most economical car is a title
which manufacturers are deperate to have.
The average fuel economy of U.S. cars is about 27 mpg. The most economical
car overall is the hybrid Toyota Prius which has a combined (city and highway)
fuel economy of 46 mpg. Interestingly, its city gas mileage is higher than
its highway mileage. This is unusual for cars and its due to the incredible
fuel saving technology in the Prius. When in the city the car is able to
shut down its petrol engine at low speeds and solely use an electric motor.
It therefore burns no fuel at traffic lights or in a queue of traffic while
standard internal combustion engines keep running, damaging their mileage
figures. The Prius has lots of other fuel saving techniques when in a city
such as recapturing energy when braking which would be lost in a normal
car.
The most economical car with a standard internal combustion engine is the
Smart Car with a combined gas mileage of 36 mpg. This car is a tiny 2 seater
with a 3 cylinder 1.0 liter petrol engine. It is lightweight and has narrow
tires which have little rolling resistance. Although very small and light,
the Smart Car is quite a safe car to be in.
The most efficient large car is the Hyundai Sonata which achieves 25 miles
per gallon city and highway combined. Its a 4 cylinder 2.4 litre petrol
engine with front wheel drive. Its a good looking car and would make an
ideal family car.
The most efficient station wagon is the Kia Rondo. It has a fuel economy
of 22 mpg. Like the Sonata, it has a 4 cylinder 2.4 litre petrol engine
driving the front wheels. The Kia boasts 108 cubic feet of passenger space
and 32 cubic feet of luggage space.
The fuel economy of petrol and diesel engines has greatly increased in recent
times. Car makers have spent a lot of time and money trying to make improvements
in this area. Some of the techniques to save fuel they came up with are:
Reduce aerodynamic drag of a car
Reduce vehicle weight
Reduce rolling resistance of tires
Use lower friction oils
Engines with variable valve timing
Fuel injected petrol engines
Turbocharged fuel injected diesel engines
Common Rail diesel technology
Use a small engine with an electric motor (hybrid electric)
Shut down the engine when the car is stationary (mild hybrid)
Recapture energy while braking (regenerative braking)