Saving gas
I have a questions about my new TCH Hybrid.
I was always told that it saves more gas to let you engine idle at a stop for a few minutes than to shut it off. This is because it takes more gas to start it. Has anyone else ever heard this? I keep think about it when I just stop for 3 seconds.
I was always told that it saves more gas to let you engine idle at a stop for a few minutes than to shut it off. This is because it takes more gas to start it. Has anyone else ever heard this? I keep think about it when I just stop for 3 seconds.
What you have heard applies to standard gasoline or diesel engines.
That does not apply to hybrids, which use what is called a "starter generator" to restart the engine in a few hundred milliseconds.
Fuel is not wasted at all.
That does not apply to hybrids, which use what is called a "starter generator" to restart the engine in a few hundred milliseconds.
Fuel is not wasted at all.
I'm not sure where the crossover point is. That said it will surely not help to shut off your car (or allow it to shut off with auto stop) for a few seconds. It totally would not be worth it. OTOH it would certainly save gas to shut your car off if you were stopped for a long time. As a guess I'd say starting the car takes the same amount of gas as idling for 10 seconds. Perhaps less on hybrids because of "instant start" and more on regular non hybrids...
Last edited by lakedude; Aug 3, 2006 at 03:09 PM. Reason: typos
Tell me more about the starter generator. I never even think about shutting off my other non hybrid car to save gas. I was just wondering in reference to my TCH.
Here's a good page which talks a little about the starter generator:
http://www.hybridcenter.org/hybrid-c...-the-hood.html
http://www.hybridcenter.org/hybrid-c...-the-hood.html
Full hybrids like the Camry Hybrid have two motor/generators aboard. The first acts primarily as a starter/generator, powerful enough to instantly restart the gas engine. The second motor is responsible for moving the vehicle.
Autostop on the HCH is very effective. This is a quote from the Car and Driver "Frugalympics" review of a couple of years ago:
So the ICE automagically starting and stopping wastes VERY LITTLE gas in comparison to running it all the time. 53 versus 40 is a pretty good indicator.
We ran this test twice with consistent results, except for the Civic's. The Honda ran the first loop in the automatic temperature mode, the second in auto with the "econ" button pushed. Econ allows the engine to shut down at traffic lights. The results were profoundly different—40 mpg with the engine running all the time, 53 mpg when the engine could shut down in times of its own choosing. This is a bigger difference than we expected, but not, it turns out, beyond the expectations of fuel-economy engineers. Loss of air conditioning on stops was tolerable; it would be less so on the hotter days of high summer. Keep in mind, though, that this improvement is possible only in stop-and-go driving. If you manage to roll through every stop, you'll have a different result.
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