Fuel-efficient petrol, hybrid and electric cars

Fed up with high petrol prices? A hybrid or electric car might be one answer.
 
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01.Introduction

Hybrid-car2-iStock-sep12

We test-drove some of the currently available models in Australia and found there's a lot to like and very little not to like about these high-tech cars.

  • The fuel-efficient petrol, hybrid and electric cars available in Australia are easy to drive and use less fuel than comparable conventional models.
  • They’re all more expensive than their equivalent petrol-only non-efficient variants, so you’ll have to drive them for many years before you recover the difference.
  • They conserve oil resources and emit less air pollution and greenhouse gases.

Models tested

What's a fuel efficient petrol car?

There are a number of technologies used by car manufacturers to make their cars more efficient without resorting to battery technology. Usually a car manufacturer will release their version of an energy efficient car with a couple of different technologies such as;

  • Guidance mechanisms for more efficient gear changing by the driver, 
  • Automatic gearing that makes the best use of gear ratio,
  • An engine off mechanism, where it turns off the engine when the car stops at lights,
  • Braking systems that feeds energy back into the car battery,
  • Low profile tyres to make it more efficient for rolling resistance,
  • Lighter body weight, meaning better fuel efficiency, for example removing the spare tyre and using lighter materials in body construction,
  • Engine construction using lighter materials and more efficient engines.

Examples include the Mazda SkyActiv and VW BlueMotion technologies.

What's a hybrid?

There are a few differing examples of hybrid technologies in the market place these days. What they all have in common is battery technology working with a petrol engine. What differentiates them is how they work together. There are three main technologies out at the moment;

A system where the electric engine can power the car on its own such as the Toyota Prius, Camry and Prius C, also called a power split or series parallel hybrid,

The system where the electric engine is designed to assist the petrol engine when it's moving, such as the Honda Civic Hybrid, CR-Z and Insight, also called a parallel hybrid.

Finally a system which is designed to mostly run on the battery and the petrol engine is designed to recharge the battery, also called a series hybrid. There are no examples of this commercially available in Australia at the release of this story.

There are also plug-in hybrids which can supplement energy generation by supplying it from the power grid however these are not yet common within Australia. Questions arise whether these are really green options are dependent on where the car owner sources their electricity (coal fired or a green energy source).

What's an electric car?

A simpler explanation than hybrid, this is an electric vehicle that is powered by an electric engine and battery. Recently introduced in Australia, there is a very slow uptake of these types of vehicles due to;

  • Higher purchase price compared to petrol engine, 
  • Range anxiety (shorter distance capacity), 
  • Lack of recharging infrastructure compared to petrol stations,
  • Battery replacement cost.

A number of these reasons will reduce over time such as infrastructure build up and the lowering of battery prices as manufacture increases. With better battery technology range anxiety ought to decrease and if electric cars become more mainstream their price will become more competitive with the petrol car. There are a few examples of electric cars in Australia at present such as the Mitsubishi i-Miev and Nissan Leaf. There are others slated for release in future.

A current advantage of electric car is the lack of moving parts compared to a petrol engine vehicle, which make servicing the car presumably more cost-effective.

 
 

 

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