Will switching off a car’s engine at the traffic lights reduce carbon emissions and fuel consumption?
Stop-start cars are the latest thing in Europe. Apparently, fuel savings of up to 15% and carbon emission reductions by 10% are possible with such cars. Will switching off your car’s engine at the traffic lights have the same effect, or is it something to do with the particular technology?
September 28th, 2010 at 9:55 pm
I think it has more to do with the technology. It takes more to start your car and turn it back on than to leave it running. Plus you might flood your fuel pump and that could be even worse fo the environment.
September 28th, 2010 at 10:23 pm
YES, It is better to shut down and restart so long as shut down time exceeds 30 seconds.
September 28th, 2010 at 11:09 pm
The starter motor in a conventional car isn’t designed for that kind of use and does not have the power to start the engine smoothly (which cars that do stop and start their engines all the time can do).
There is also the fact that using the starter motor takes power from the battery which then has to be recharged (which increases power usage and therefore fuel usage) along with the fuel needed to get the engine turning over.
If you expect to be waiting a long time then you might be better off switching the engine off but for most cases it’s probably better to just leave it on (besides, having to wait for the engine to crank over before you start off might annoy those behind you, especially if the traffic light doesn’t stay green very long).
September 28th, 2010 at 11:25 pm
Everyone here has an opinion but no technical argument or proof.
The point is interesting because it may help the planet though.
I do not consider the arguments which claims are based on social terms ( “I am going to wait because of you + insult “).
Many official guidelines about automobilist behaviours DO say that it is better to shut-off the engine when idling is expected. Expected time to do so vary (I read 10 secs recently ! see source ). Most say 30 seconds. The engine should be “hot” though (min 5 km) : it restarts far more rapidly and smoothly.
It is not a proof but it seems correct to shut-off the engine when expected idling, even a classical one.