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Thread: alternator load vs fuel economy

  1. Default alternator load vs fuel economy

    not many studies done on alternator loads effect on fuel economy. i attended a class on gm's new strategy to turn off the alternator under cruising conditions and the results are nil on an individual basis as far as fuel economy goes. tenths of a gallon in the name, but on a national scale equals alot of savings. which means alternator load does very little to fuel economy. the extra load a hho generator puts on the alternator does not lower fuel economy enough to negate the generator but may cause the alternator to fail prematurely.

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    not many studies done on alternator loads effect on fuel economy. i attended a class on gm's new strategy to turn off the alternator under cruising conditions and the results are nil on an individual basis as far as fuel economy goes. tenths of a gallon in the name, but on a national scale equals alot of savings. which means alternator load does very little to fuel economy. the extra load a hho generator puts on the alternator does not lower fuel economy enough to negate the generator but may cause the alternator to fail prematurely.


    Wait a minute if that was true then you could run your car on HHO. NO CAN DO. I think you should test it and report back. There is no free power!! Just try putting a load on a generator set and see how it pulls the engine down and requires more fuel. This does not take a rocket scientist.
    "Democracy is two wolves and a lamb deciding what to have for dinner. Liberty is a well-armed lamb."

    ONE Liter per minute per 10 amps which just isn't possible Ha Ha .

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    putting a load on the alternator does load the engine down. but it is a small amount. just by running the fuel pump and the coils is around 8 to 10 amps, running the blower motor is around another 8 amps and the wipers is another 5 amps, and nobody complains of getting worse gas mileage at night when its cold outside. gm says they save around 1% fuel mileage. i will test it with my car. hard to do because it is a base model and only has a heater headlights and wipers. and i don't see hho generators as free energy because water is the fuel, its not from nothing. i just think modern engines need more r & d to harness the hho enough to run completely on or at least get more mpg. i think of it as instead filling the car with gasoline, building a small refinery and converting crude oil into gasoline in the car. yes it would lower efficiency, added weight and electrical load. actually i don't even know if that would be possible but is sounds good enough. i think there's alot more we can get with hho on demand.

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    If you are planning to make only a couple hundred milliliters a minute then it will not make much difference just using 3 amps. The average reactor takes 15 amps or more to make 1 liter a minute and if you are going to make 3 LPM then 45 amps will be required. Many have experienced a loss in mileage when not done right or no gain because of the drain on the engine by the alternator. I suggest you do some testing and report back.
    "Democracy is two wolves and a lamb deciding what to have for dinner. Liberty is a well-armed lamb."

    ONE Liter per minute per 10 amps which just isn't possible Ha Ha .

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    alright ran into a little problem. with my car being base model and all, i looked up the fuse ratings for everything electrical. turns out everything added up is only about 30 amps and that being optimistic. im gonna have to find an old blower motor in the shop and rig it up to do this test. my alt is rated at 60 amps so i thought a good safe range would be 45 amps. im going to make this test with the least amount of variables as possible, so im going to use a pulse width calculator to calculate fuel consumption as i drive and i'll use my shops oscilloscope to monitor injector pulse width so it will be real time. ill do 2 runs of each loaded and unloaded alt, and in 3 different rpm ranges idle 40 mph and 60 mph. gonna be busy this week so ill probably wait until the weekend to do the test

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    Alternators have a peak rating designed to withstand said peak amperage for X amount of time. This is important because if you are constantly hitting that peak or "pushing the edge" you will potentially end up with a dead alternator and you probably know where things break down from there. That being said, I think your approach is the right approach and I could almost bet money that many individuals here are overdriving their alternators right now (asking why they are losing MPG). I say this because not much talk happens in the direction of pre-install alternator condition on these forums. You could have a 60A peak rated alternator and it could only be capable of 45A peak because the brushes are worn, ect ect. Post the test results back as any info is helpful info for noobs here.

    Related: http://www.hhoforums.com/showthread....4007#post54007

  7. Default test one idle warm engine

    ok, had a quick second and did a idle test. took some pictures but i haven't been able figure this dang thing out so ill just tell you. the car was fully warmed up used an inductive low amps probe to measure current and back probed my injector and put them side by side on the two channel scope. first snapshot was at idle with no alternator load amp clamp shows 6.8 amps and my pulse width is 32.6 ms. next snap shot was showing 31 amps and 38.9 ms. my next snapshot was at 2000 rpms amperage jumped up over 40 amps which was my limit so all i know is that it was over 40 amps pulse width is 17.2 ms. and the last snapshot was 2000 rpm with no load 12.1 amps and 10.8 ms. im not the biggest expert on tbi so im gonna assume that pulse width is so high at idle and lower at 2000 rpms because its pulsing 2 cylinders at once at idle and going to each cylinder at 2000 rpms. now since i was at idle and was not moving i really can't use these numbers for mpg. but i can compare them. so thats a 19.35% increase in pulse width at idle and 59.3% at 2000 rpm. another thing to note is that my car is a 91 honda civic with a 1.5 liter engine with honda's version of throttle body injection and a distributor. it has 295,000 miles on it. the test at idle showed that the alt was fully loaded at that rpm because the output increased when i raised the rpm to 2000. also the alt will have its biggest impact on the engine at idle because the engine output is low. also my car is a small 4 cylinder so alt load will affect it more than really any other engine in the world. and i plan on doing this test with our high amps probe too because i don't fully trust the low amps probe its been messing up lately.

    ps ok i figured this dang thing out heres pics of the scope
    Attached Images

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    You are headed in the right direction and I will be interested in your findings. I have always used 1 HP for 40 amps. Now how that relates to fuel economy is another matter and is much more involved. The actual figure is slightly less than 1 HP. This was a calculated figure and I would be interested in seeing how your tests match up. There is more to this game than one thinks. There are a lot of variables. Electrical power on a vehicle is not free. It comes as a direct result of consuming fuel within the engine to drive the alternator. With a typical engine efficiency of 40%, a belt efficiency of 98% and an alternator efficiency of 55%, this leads to an overall energy conversion efficiency of only 21%. I am not a math person and can only relate to this in my testing and the above mentioned is from those who are math orientated who are recognized as experts or at least supposed to be. LOL
    "Democracy is two wolves and a lamb deciding what to have for dinner. Liberty is a well-armed lamb."

    ONE Liter per minute per 10 amps which just isn't possible Ha Ha .

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    ok so did a quick test on my lunch break because i was feeling frisky. the numbers are a little confusing because i don't deal with tbi very much and i can't find much info on the computer strategy yet. fully warmed up engine first test 60 mph no load 2900 rpm tried to maintain cruising speed for 5 seconds hard in my car because it doesn't have cruise control and i was trying to keep an eye on the cars in front of me. so 60 mph no load 2900 rpms pulse width 4.9 ms. next test 60 mph 2900 rpm fully loaded bounced between 5.0 and 5.1ms. i did the 40 mph test but now looking at my results i did one at 40 and one at 45 so im going to have to redo that one. but at 60 mph the load should be the smallest on the engine so i did both ends of the spectrum so far and i can speculate what the middle would be. any one know how to calculate this my lunch break is ending and i don't have time. or i will do it later at home

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    i searched forever it felt like and still didn't come up with anything i think i might know. i looked for an algorithm to calculate mpg with pulse width fuel rpm etc. turns out that isn't a very popular algorithm. i found one but im not sure what i've actually come up with. here is my results


    X/(C*0.0000212*Y*Z)

    Where:

    X = Vehicle Speed
    Y = Engine Speed
    Z = Base Pulse Width
    C = Injector constant (lbs/hr)

    2900 rpm
    60 mph
    4.9 ms pulse width no load
    5.1 ms pulse width + 40 amps load
    235cc/min injector max flow


    60 mph / 6.7480448 = 8.8914643838760525122773340212561 - 4.9 ms

    60 mph / 7.0234752 = 8.5427795060769916294429287655205 - 5.1 ms

    now i have little to no idea of what i just calculated. unless some one here knows im going to spend the next few days figuring out what i just figured out.

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