Lower Car Emissions

Continued from Car Emissions.

The best results seem to have a common factor and that is to drive your car at the lowest speed manageable in the highest gear, this does not mean to chug along in a high gear with your car struggling with the low speed, but to drive at a speed at which your car is comfortable with in the highest gear (this is the sweet spot). Unfortunately this is not always possible as some cars most effective speed could be 60 to 70 mph which cannot be done on all roads due to speed limit restrictions.
You will usually find your sweet spot sits between 2000 and 3000 RPM with a load of 50%.

The other point to keep in mind is acceleration as slamming your foot down emits more Co2 and consumes more fuel than gently easing your car up to your sweet spot, 0-60 mph testing is probably best left to track testing. Also a number of modern cars have been designed to be at full throttle when the accelerator only pressed to 50%. The reason for this is to make owners feel that their car is more powerful than it really is, this again should be kept in mind when accelerating in a modern car.
Another myth is that coasting with the clutch in will save fuel, this is not always the case as to keep the car ticking over the fuel system kicks in, the best way to save on fuel is to use the momentum created by your vehicle, keep your clutch up and above 1500 rpm as this means that the fuel system is cut out. A smooth driver = an economical driver.

Previous tests have provided some interesting statistics and for example if in your car the most cost effective and economical journey took 18 seconds and resulted in fuel consumption of 34 mpg, but you completed the journey in 22 seconds (thinking driving more slowly would save you more money and lower Co2 emissions) then you would actually only average 28mpg and the emissions would be expected to be higher.

This may not appear to be too different but over a period of 1 year this would actually result in 1 tonne more of Co2, the key is know your car, know your sweet spot and plan your journeys well, avoid traffic jams and be smart.

Continued from Car Emissions.

Updated on 21st April, 2009

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