Cars are a major contributor to pollution in cities. This is made worse by the traffic jams that plague many large cities, as not only do cars spend large amounts of time polluting without going anywhere, but they spend most of their time stopping and starting. A car's fuel consumption is highest when it is moving off from stationary and every time the car stops it loses hard earned kinetic energy.

There are many more environmentally friendly alternatives to the traditional petrol or diesel guzzling engines, some of them more viable than others, for example solar cars, fuel cells, natural gas or electric cars. Another alternative is the hybrid petrol/electric vehicle. The main difference between the hybrid car and the other alternatives mentioned is that Honda makes a mass produced hybrid car, whereas the others seem to feature mainly in documentaries and car shows.

Electric cars

Battery powered electric cars have some nice points. They are quiet (some say too quiet, making accidents more likely because it is more difficult to hear them coming). They release no gases or particles. An electric motor, unlike a petrol one, can start and stop at will, so there is no penalty in having the engine automatically turn off when the car is motionless. The one killer is that they have very limited range, usually around 100 miles before needing a lengthy recharge. You will often also lose all of your boot space to rows and rows of heavy batteries.

Best of both worlds

Hybrid cars, like the Honda Civic Hybrid try to get the best of both worlds. They have both an electric and a petrol motor.

The electric motor is always used to assist the petrol engine. Honda call this the Integrated Motor Assist or IMA system. Petrol engines are less efficient at low RPM, for example when accelerating from stationary so the electric engine will help out. At 1000 RPM, the electric motor increases torque by 66% compared to the same engine without IMA. If your speed drops below 10 mph, if battery levels are sufficient and engine temperature is high enough, the petrol engine will actually switch off. This usually happens at traffic lights and stop signs. The car is however clever enough not to turn off during stop and go driving. When you eventually move off, the electric motor acts as a starter motor and automatically gets the petrol engine going, and assists it during the initial, fuel guzzling acceleration.

And then I plug the car in and wait for 8 hours? You never need to plug this car in to charge the batteries. The batteries can recharge in 3 ways:

  • Braking: why waste your kinetic energy by turning it into heat, when you could be using it to recharge your batteries? In this car when you brake, the electric motor acts like a dynamo, slowing the car and charging the batteries. If you need to brake sharply, the Hybrid Car also has "classic" brakes that will be used if necessary.
  • Coasting: When you are coasting, a small part of engine power will be diverted to recharging the batteries. The faster you are going, the more power is diverted, the reason being that petrol engines are normally more efficient at higher speeds.
  • Acceleration: Now this may seem pretty stupid, as here it isn't "spare" energy that is being used. Why use energy to charge the batteries when it could be used to turn the wheels? This actually works out because it will only kick in if the car is accelerating in an RPM range where the engine is efficient. This ensures that the electric motor will always have enough power to assist during the less efficient periods.

The car's computer is programmed to never let the batteries go flat, if power levels drop too low, one of the recharging methods will kick in. All this means that you don't lose too much space to the batteries. A standard Civic Sedan has 12.9 cubic feet of cargo space, a Civic Hybrid has 10.1.

Other features

  • Interesting gauges: In addition to the usual set, the Honda Civic Hybrid also has a gauge to show you whether the batteries are being recharged (in which case the gauge glows green) or if they are being used by the motor (the gauge glows red)
  • Intelligent engine: For once this isn't all hype. The petrol engine used can actually switch off individual cylinders if they are not required, thus saving fuel.
  • Continuously Variable transmission (CVT): An automatic transmission normally just does what a human driver would do, shifting gears as needed. With CVT however, there are no shifts: The gear ratio changes in a continuous manner, in such a way that it is always optimum.

All of this doesn't come free. To be precise it costs $20,550 ($19,550 if you can do without the CVT). A normal Civic Sedan can be acquired for only $13,000 dollars. On the other hand one of those will be doing 32 mpg in cities, and 38 mpg on motorways, whereas the Hybrid is rated at 48 and 47mpg. These figures are actually quite interesting as you can see the job the electric motor has been doing, the Hybrid is just as efficient in both driving situations.

In all likelihood, unless you do a lot of driving you probably won't win back the difference on fuel savings. However depending on countries there are a number of government subsidies for purchasing "clean" cars. And of course the warm cuddly feeling you should get from being kind to your planet! You don't even have to look like a freak: the Hybrid Civic is very similar in appearance to a normal Civic. model_overview.asp?ModelName=Civic+Sedan