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Old 06-03-2012, 05:22 AM   #5131
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Originally Posted by scottrnelson View Post
If you can start the engine without pressing the gas pedal down, which should be the case when it's hot, it doesn't use any extra fuel at all to restart an engine. On all but CV carburetors (usually only on foreign cars, like the 240-Z) if you pressed the gas pedal down the accelerator pump squirted more fuel into the carburetor. Normally when the engine was cold, you would press the gas two or three times which would both squirt more fuel into the intake and set the automatic choke, then you would start the car. This would be the case for American-made cars from the 50's and 60's.

So if it could be restarted without pressing the gas pedal down at all, even 20 seconds would save fuel.

Modern fuel injected engines would be even better, because they don't squirt in any extra fuel.
Those accelerator pumps didn't have temp sensors to shut them down?

Sure, today it makes great sense to shut off if you have a hybrid to start on the electric motor and then the engine kicks in right off such as the Prius does. Presumably, after about 30 seconds, the energy it takes to regain battery charge is less than the fuel spent idling. I'd guess some engineers have figured this out long ago which is why, to my knowing, all hybrids do this.
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Old 06-03-2012, 06:10 AM   #5132
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Originally Posted by Kannonball8 View Post
But the shutting down the engine thing is what bugs me, maybe you can save a small amount of fuel, but, what about wear on the starter and battery? I start my car in the morning and drive 12 miles to work, I have the possibility of getting stopped at 4 traffic lights during my drive. This could give me a total of 5 starts each way or 10 per day instead of 2 per day. If I only use the vehicle to go to work and I work 240 days per year, I'm starting the vehicle 2160 extra times a year. You can't tell me I'm going to save enough gas to cover the starters and batteries (and maybe ignition switches) I'll use up. (or am I completely wrong?)
Bruce
Those tiny savings across an hour or two's commute per day per week per year add up to considerbale savings.
As for additional load on your battery and starter - if your engine is warm and is maintained there is insignificant wear and load on your battery.

You're obviously not aware that most car manufacturers these days have cars who's engines automatically stop and restart in traffic. These engines are fitted to more or less regular petrol and diesel cars (ie not just hybrids). It helps give them the edge with fuel economony and while I haven't tried it, reviews I've read have said that it works flawlessly - well in premium brands anyway.
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Old 06-03-2012, 06:13 AM   #5133
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Originally Posted by slide View Post
Those accelerator pumps didn't have temp sensors to shut them down?
It sounds like you have no idea what an accelerator pump is.

It was something inside the carburetor that squirted extra fuel into the intakes every time you opened the throttle. It was there to make up for the air being able to speed up more quickly than the fuel and helped keep the air/fuel mixture more correct. Usually it was either a plunger (think of a syringe) or a rubber diaphragm. It was 100% mechanical, so no temperature sensors involved. As far as I know, the ONLY temperature sensor of any sort used in American engines in the 50's and 60's was the cooling system thermostat that regulated how much water went to the radiator.
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Old 06-03-2012, 06:57 AM   #5134
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Those cars that have the auto shut-off, that are not hybrids, have huge heavy duty starters. Hybrids don't use their starter motor unless their battery pack is drained. It's all the electric motor's doing (pretty trick stuff).


On a normal car, even when warm, if you are constantly starting and stopping it, you will wear that starter motor out much faster then normal.
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Old 06-03-2012, 07:18 AM   #5135
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Old 06-03-2012, 09:19 AM   #5136
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Old 06-03-2012, 11:28 AM   #5137
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Old 06-03-2012, 04:37 PM   #5138
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Those cars that have the auto shut-off, that are not hybrids, have huge heavy duty starters. Hybrids don't use their starter motor unless their battery pack is drained. It's all the electric motor's doing (pretty trick stuff).


On a normal car, even when warm, if you are constantly starting and stopping it, you will wear that starter motor out much faster then normal.
Let's put this in perspective. A typical family might start and stop their car engine 20 times over a weekend and god knows how many times during the week. That starter motor will last 20+ years. So starting and stopping it during a few times during a commute isn't going to make a lot of difference.
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Old 06-03-2012, 04:53 PM   #5139
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Originally Posted by hoadie72 View Post
Let's put this in perspective. A typical family might start and stop their car engine 20 times over a weekend and god knows how many times during the week. That starter motor will last 20+ years. So starting and stopping it during a few times during a commute isn't going to make a lot of difference.
The average trip length for urban vehicles is something like 10km/6miles; the average traffic light interval is probably more like 0.5km/0.3miles. Restarting at every second traffic light instead of just once per trip has the potential to reduce the life of starter motors and ring gears by a factor of ten, bringing your hypothetical 20 year starter life back to just 2 years.

Automated engine off and restart at stops in traffic lights has only become viable with larger batteries and starters.
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Old 06-03-2012, 05:05 PM   #5140
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Originally Posted by eepeqez View Post
The average trip length for urban vehicles is something like 10km/6miles; the average traffic light interval is probably more like 0.5km/0.3miles. Restarting at every second traffic light instead of just once per trip has the potential to reduce the life of starter motors and ring gears by a factor of ten, bringing your hypothetical 20 year starter life back to just 2 years.

Automated engine off and restart at stops in traffic lights has only become viable with larger batteries and starters.
Mazda has a system for their direct-injection engines that doesn't require using the starter motor at all. The engine is stopped with a piston just past TDC ready for the power stroke. To restart, fuel is injected and sparked. Off you go.

To be fair, idling a modern 4-banger for an hour uses a ridiculously small amount of fuel. You'd have a bigger benefit from reducing aero drag by slapping on an underbody tray or finding a way to take 100lbs out somewhere.
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Old 06-03-2012, 05:16 PM   #5141
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Remember when we used to talk about stupid questions people ask you when stopped? Those were the days.
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Old 06-03-2012, 05:21 PM   #5142
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"Hey, I heard goldwings have air conditioning, so why are you complaining about how hot it is"?


Yeah. 96 degrees. Stuck in traffic, and my phone crashed because of the heat, leaving me with no music.

Also, I was almost late for school.
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Old 06-03-2012, 05:24 PM   #5143
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Back to the headlights-off question. Any inmates from S. America know if it's still done?
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Old 06-05-2012, 09:43 AM   #5144
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Back to the headlights-off question. Any inmates from S. America know if it's still done?
I'm just spit-balling here but older cars had generators instead of todays modern alternators, generators will not make sufficient amps at low rpm, idle, to power the lights so the battery is getting drained at idle. Also, generators need a little voltage to "excite" them into working, produce amperage. So, if the battery gets too dead the generator won't come back on line. This would be worse on older, less maintained vehicles.

And, to get back on track.....

While putting my helmet on outside of an Autozone the other day...

Mullet head: (Looks up at storm clouds) Looks like it going to rain.

ME: (Looking up at storm clouds) Yup.

MH: I hope you not going too far.

ME: Baltimore, home, about 130 miles. (No, I did not ride 130 miles to get to the Autozone, its conveniently near my parents house)

MH: Whatcha gonna do when it rains?

ME: Get wet. It happens.

MH: I never ride in the rain, heck, my Harley has never had a drop of rain onnit.

ME: Ah, well, have a nice day!
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Old 06-05-2012, 07:44 PM   #5145
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That phenomenon is not exclusive to bikes. I had a lady ask me once if I knew "George", because he was in the Air Force.

She didn't know his last name, what he worked as, what squadron he was in, or if he was even at my base anymore. She just thought that I would know.
When I was in the army and asked "do you know John, he is in the 82nd Airborne too?", I would say "Yeah, bummer about his leg." then walk away.
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