Just throwing some ideas out there, but I was thinking what if you take a electronic motor designed to turn a mechanical water pump and attach it to the power steering pump.
http://www.jegs.com/cgi-bin/ncommerc...97&prmenbr=361
Something like that ^. Just swap out the p/s pulley and replace it with one given. Mounting the rest wouldn't be too hard and It would save some more hp from your setup.

Only thought was, it says for all of those types of electronic drives, Drag Race Only, most of the time I dont give a damn if they say this, but it's probably not meant for continuous use. So the motor could burn out easily from over use if it's only meant to be seeing a minute or so of use ever now and then. Let me know what you think.

 

Why would it save HP? You're doing the same amount of work to turn the pump, only instead of using mechanical energy directly, you're converting to electrical and back which will have more loss.

 

not following you there.

If your alternator can handle the load why do you say you'll lose more power

And it's not saving hp, it's freeing it up, by using the same technique as it's original purpose is.

 

The energy to turn the pump has to come from somewhere, you can't get work done for free. Belt-driven, you're driving the pump directly without much loss, and most of the energy you're using goes into pumping the fluid. Electric motors aren't 100% efficient, so some energy is wasted as heat instead of being used to turn the pump. The alternator isn't 100% efficient either, so it requires more mechanical energy than it produces electrical energy. That adds up to a net loss.

Not only that, but an electric motor is going to add weight.

 

Adding, weight it might be a few pounds, who really cares about that.

But as for the wasting power therefore losing horsepower holds water theoretically, but higher power alternators are built with better parts that produce more amps with out more effort to turn them. So the 'wasted energy' is really just energy that the alternator can put out without more effort.

There still is wasted energy from the ineffeciantness of these pieces, but the higher amp alternator would compensate for this.

 

Probably more than a couple of pounds for a motor with enough torque to drive the P/S pump.

Those alternators are only better than other inefficient alternators. Even with the most efficient alternator available, you're using more power to drive the pump with an electric motor than you would be if you'd used a belt drive.

If it was better (ie. cheaper, more fuel efficient or more durable), car manufacturers would have done it long ago.

 

An alternator can only put out in electrical energy what is put into it as mechanical energy minus whatever losses you get from the belt drive, inefficiencies/losses in conversion… since you’re adding one extra conversion step from mechanical to electric and then back to mechanical and an extra drive linkage, it will NEVER be as efficient as just driving the pump straight off the engine.

And a higher amp alternator DOES draw more power from the engine, where they’re more efficient at then older designs is that they are capable of drawing that power over a wider range so that they can provide sufficient output for a lot of accessories at lower rpms then older alternators, not that the conversion from mechanical to electrical energy is more efficient.

Second, it will take a seriously beefy motor to drive a PS pump under full load, a water pump motor will not do it, not even close. A motor that could do it would likely be in the >25lb range.

Now if you really wanted to do it, it’s been done and you could just adapt one of the OEM setups like the electro boost assembly off of a fiero. OTOH, it has not been done to save hp like you suggest but for packaging reasons.

Now after all the negatives, there is a positive: you need more help with power steering at low speeds (like in a parking lot) when you don't need the HP than you do at high speeds (like on a road course, highway, or especially at the dragstrip), so going to an electrically boosted setup _might_ actually buy you something WRT to available HP when you really need it. Overall your setup would be less efficient (might possibly be reflected in a lower gas mileage…) but you may gain a few HP (probably in the range of 5-15hp) when you're trying to accelerate.

 

Ok, guess it was a bad idea then, but what i'm hearing you guys say is that this set up, used on the water pump as initially intended, won't benefit you at all, but instead hurt performance, in reference to what you said about the p/s assembly.

 

First, like I said, a water pump is significantly different load wise.

Second, like I also said, overall efficiency would go down as would average power production, but as long as you can prevent the alternator from trying to generate extra current to power the motor at WOT it will benefited performance.

 

So, if a strong enough motor was to be attached to the p/s and the no extra strain is put on the electric system, it will benefit. Am I reading you right?

 

Not sure on load , but the cobalt has the electric control steering the box size is roughly 4" x 10" x 2" deep. I built an oven at my work to cure the electronics in it for gm. The said the wanted to go to electric assist because at lower speeds the ps pump is not beneficial. The cars that they builid in germany is currently using it.
The goal is to eliminate as much hydralic type of hosing and go to more electronics. I believe cause they want to go to a composite frame. So there going to need less weight. Maybe you can steel one from the cobalt and get the wirng diagrams. I think tho it would be one more thing to fry out compared to how long a ps pump actually lasts.

Dan

 

The P/S pump works fine at low speed, it's at high speed that it does nothing. Rather than messing around with electric motors, I wonder why they don't just put an electric clutch on it.

 

I might have that backwards who knows I never listen to them at meetings . You know these guys are more worried if the titty bar is open yet., go figure maybe thats why gms been having so many problems . I know there long term program is to remove as much items that use fluid transfer ,then to go to electronic so when they do a composite frame it will not be stressed. I know I think there big thing right now is hydro forming frames. But you never know they change direction as quick as they start. heck some times we build finishing units for them they buy them off and take them to a dump or leave them outside to rust. I wish I had money like that to **** away. What I see with gas prices right now , they will all get on that crazy path of device making for saving gas. What will end up, we will all be asking questions down the line can we rip this off, do I need it.

Dan

 

in WOT performance



I can’t see how going from hydraulic boost to electric would have any effect on the frame stress.

Most likely it’s a bottom end thing, with fewer things to leak fewer will, fewer warranty claims and the claims that you get will call for less labor…

I just did a blower setup on an Infinity G35… that thing uses aluminum frame members tied together with composite crossmembers (ex, the core support was composite bolted to the frame stubs...). In some ways kinda cool… again, from a labor standpoint most likely a cheaper approach, of course the parts are more expensive, but labor is almost always more expensive then parts.

 

If you really want to improve your performance by eliminating the PS pump being driven off of the engine. You could always swap in a manual steering box. But good luck trying to turn the wheel when your not moving!!

 

Going back to the origional topic.....

The only way you would potentially lose power by using an electric drive on the ps pump is if you need to go to a higher amp alternator. Period.
But if your current alternator puts out say 105amps, the hp draw on the engine is the same, regardless of whether you're using all 105 amps or only 10 amps.

Further more, I am not sure exactly how much power it takes to turn the ps, but it cannot be that much. The main reason people swap to a manual rack is for weight savings, not power. On top of that, the p/s will work fine running at a low rpm-in electrical turms that means less current draw. I have no problems at all turning the wheel while rolling at maybe 2mph and idling at 600rpm, there is no reason that would not hold true for an electric motor turning the pump at the same speed.

It would be easy enough to figure out what size pulley you would need based off of the rpm of the electric motor.

So, the only dilema is finding a drive motor that is streetable, and not a strip only application.

 

Some of GM's new cars like the Malibu have electric power steering pumps and it was done to save HP and increase gas mileage. But that system is completely different then just slapping a motor drive on a PS pump. First the new cars that do it are rack and pinion. Second the whole system is variable. So for example on the highway when you are not turning the wheel very much is will reduce line pressure a lot. It's automatically adjusts for load on the steering. So if you are going WOT in a straight line it will not be using engine power to turn the power steering pump for nothing thus giving you more power.

Putting a motor on a power steering pump will not save you power but decrease your power output because you are converting mechanical energy to electrical energy back to mechanical energy and there is looses in every step of the process.

 

That just isn't true. Turn the blower motor on high, turn on the headlights, and turn on the rear window defogger and watch your idle speed dip.

 

The reason the idle speed dips is due to the fact that the alternator is not supplying enough power due to the low rpm in which it is spinning.......Try it on a cammed motor that requires a higher idle, and you will not see a dip in rpm....unless your alternator is not strong enough.

 

You are not getting the point, but basing everything on a different physics standpoint. In the ideal set up, what you are saying would be true....
But with that being said, we (or any cars for that matter) do not have "smart" alternators...period. They do not adjust based on the current amperage being used..... The alternator requires the same hp to turn regardless of the power draw your car is using. The only time an alternator requires more or less power to turn is when physically changing it out for one rated at higher or lower amps. Or underdrive pulleys which are a different subject.

For example, if you have a 105amp alternator, and only use 80amps 99% of the time, than adding an electric motor that requires 15amps is not going to cost you power, but rather making use of the electrical current you were not using before.

Now if you added an electric motor for a wp and ps, but also needed to install a higher amperage alternator, then what you are saying would be true.

If that isn't clear enough (do to my poor explanation), just look at the facts...Electric water pumps are proven to increase hp. No if ands or buts. And they use the same transfer of energy that you claim is going to cost you hp......

 

How does the alternator not supplying enough power cause the idle speed to dip?

 

It doesn't work like that, you can't "not use" current. With open terminals on the alternator, the alternator only takes whatever power is required to spin the armature and overcome the friction in the bearings. At a 105A load, the alternator requires an extra 2 HP (105A x 13.8V = 1449W = 1.94HP), assuming it was 100% efficient, which it isn't.

Take a look at why electric water pumps save power and you'll come up with a few ifs, ands and buts.

 

Please do explain...
From what I can tell, the power savings comes from the fact that it is electrically driven....and not using belt driven hp....

If you are striving at efficiency or the internals you need to explain....Because if it isn't the "electric" portion of the pump making the power, you lead me to assume it's in the design. But if that was the case, I think we would see belt driven water pumps claimaing to save more hp than electric water pumps.....

Further more, if it isn't the "electric" portion saving the power, then please explain to me why the electric motors w/belt setup on belt driven water pumps save power.

Please do explain
Because now I am starting to get confused......if 105 amps only needs 2hp at 100% efficiency....lets say the effieciency is horrible and requires 5 hp to get the 105 amps, how is it that elctric water pumps can save 10-15hp?
I'm not being smart, it is a serious question.

 

True on all the cars I have owned and driven. Alt needs slightly more RPM to put out max power. I havent driven anything yet that adjusts idle like when you put the AC on, just the voltage drops when you have all the accessories on.

 

You couldn’t be more wrong.

The regulator applies power to the field coils to maintain the set voltage (usually in the 14.6VDC range) at whatever point in the engine harness the sense circuit is hooked up. As you turn more things on there is more power applied to the field coils and the HP draw goes up. Take your typical 100A alternator, if you drive it with an electric motor you can drive it with almost anything without any power hooked up to the field coils. If you start applying power, as the power to the coils gets higher the load gets higher, somewhere around 9-10VDC that 100A alternator will stall (and throw the thermal breaker…) of your typical 5HP, 240VAC/20A motor (the biggest that you’ll be able to run with most residential services). Oh, and without a load on the alternator, the open circuit voltage will be somewhere in the 115-130VAC range at that point.



There is a very good reason why the PS pump typically has a double belt pulley on it and the alternator only has a single. And yes, the PS pump can instantaneously draw more power then most alternators.

Idle and just about everything else is compensated for low battery voltage by the ECM, V will not effect it. The reason that the idle drops is that the alternator draw increases and there is no compensation built into the ECM for it and the best that it can do is react to the RPM change after it happens, if it can even react that much.



Real world physics vs whatever happens to physics after half a bottle of JD?



Again, no idea where the hell you’re getting it, but it’s wrong. Internally regulated alternators adjust their output based on the external sense circuit connection, older, externally regulated alternators are regulated by the regulator output to the field coil terminal which again, is regulated based on the sense voltage. If you ran an alternator at full output and very light load you’d kill just about everything in your electrical system almost instantly, and even at most of it’s output under medium load you’d quickly overcharge the battery and ruin that.

the only reason that they “increase” (actually use less) power is that as your rpm goes up it runs at the same speed, they always run at the same speed, where a mechanical water pump accelerates with the engine and draws increasingly more power till the impeller cavitates and things pretty much go to hell, quickly.

On average they draw more power then mechanical pumps, at low rpms they draw more power, which is why you don’t see them from the OEM’s, but at WOT, where we measure power and performance they draw less.

 

Ok, I was completely mistaken on how an alternator works, and I appologize for posting the wrong information. This is not a smart a$$ question, but you are saying we could run a 140A alternator, and the hp draw would be the same?

However, I still cannot justify "losing power" because you are running electric accesories previously belt driven. That, my friend is the JD approach to physics. The real world world view is simple....these accesories do not have to turn at the same rpm as the engine. So, yes, in this real world application, you do gain power, unless you want to measure power at idle... Acually, you posted the same idea later in your post, contrary to what you stated earlier..

Considering most electric water pumps only require 6 amps (at flow rates of 35gpm+), plugging that into the formulas used earlier in the post, 6 amps only requires less than 1/5hp. I think it would be safe to say that by the time you are at cruising rpm and higher, you have more than made up for 1/5 hp required to power the electric motor....

Further more, if the power steering pump is as draining as you say, then it would be even more effective to use an electric motor. If a water pump can rob as much as 20hp, then I think it is safe to assume you are saying that the steering requires even more power. So even if you use something crazy like a 30amp motor, it is only going to cost you less than 1 hp in the alternator.... So why not go with a 140amp alternator that at most is going to require 5-6 hp, and save a potential 40+hp at peak power with electric driven accesories?

I am not trying to create a grudge or anything of the sort. Your explenation of how an alternator works was informative and I thank you. However it only makes my point stronger. You are not losing power by electrically driving accesories unless you are looking at idle and lower rpms.

 

Pretty much… but if you’re talking something like the 145A used in the 4th gens, really there would be a slight savings because it’s more efficient and has a lower rotational inertia then the earlier ones.



Reread everything that I’ve written in this thread already, I was very careful to differentiate between average HP (across the whole power band and under all conditions) vs high rpm, low rpm… you’ll find that I was very consistent.



I’m sorry, but you’re making this excruciatingly painful… I can’t make heads or tails of whatever you’re doing to the numbers here, but IF the WP really draws 6 A and is somewhere in the 1/5hp range (power use), then you’re feeding it roughly 25VDC. Somewhere, your math is AFU unless you’re figuring for a 50% loss…, and if you are figuring for a 50% loss then the rest of what you wrote makes no sense.



GRRR… simple… because a PS pump is not always working. Without turning the steering wheel it is drawing almost nothing. As the hydraulic actuator (PS gear, hydroboost brakes…) is put to work, sees a higher load… the pump works harder and draws more power.

Unless you’re spending a lot of time steering left and right at slow speeds while drag racing or on the dyno, you will not see any difference. I would actually suspect that you’d see a loss at the dragstrip because steering around the water box, getting it straight during the burnout, straightening things out in the lights… is all going to use power, and with a mechanical setup it will use power at that instant, with an electronic setup it will have to recover after the fact, while you’re staged and making your pass.

I’m sorry, but you’re looking at this all much to simplistically WRT to the power use (IE, there will be more with going to electric accessories since you at a minimum have 2 mechanical to electric conversions with their inherent losses) and WRT to when the power use happens.

 

Ok, now it finally goes together. I thought that the power steering was a constant draw. Basically, I was always under the impression that it worked like the water pump. Pulling x amount of hp for a given rpm. I did not know the ps pump doesn't "work" all the time. Kinda sux, cause had somebody said that earlier(or if I read over something), it could have saved you a lot of typing

As far as the numbers go, I just used the amps x volts=watts formula used earlier in this thread, converted to hp and then figured in a rough 50% loss. It's been too long since I took calc and engineering physics.... I went in the military, and had to change my major to management....and going off this thread, it's looking like it's a good thing I didn't become an engineer

 

Not sure how this will work in your application- but the new Cobalt uses an electric power steering pump.

Look in a salvage yard in the next few months as these cars get out onto the street.

 

The cobalt and the malibu I believe uses it , but it sounds more like a hassle to me . Heck last thing that fails on these cars seems to be the power steering pump. Now maybe some one can steal one of the turbos that they have on the cobalt and hook it up to a 305

Dan

 

turbos? some of them are supercharged but none turbocharged that I know of

 

The new GM cars, BMW and Mercedes... all are switching to a computer controlled drive by wire steering system. There is no machanical linkage between the steering wheel and the wheels, its all electronics.

 

trying to stay on topic here, but from what i have read in the past, it was my understanding that when they started to put electric P/S pumps on, the cars having them would have 2 separate electrical systems, the first would be the 12 volt system & would power things such as the lights, sound system & computer systems. the second would be a 42 volt system & would power the P/S pump & window motors with other things to follow at a later date.

i never get a look under the hood any of the new cars until they are 3 ~ 4 years old.
do the new colbalts have 2 electrical systems or just a standard 12 volt system?

there has been talk about scraping 42 volts & going to 72 volts or maybe even higher.

2 things i am looking forward to with the high voltage systems are,
#1, an eddy current service brake system,
#2, the one most important to me, electronically controlled valves, IE no camshafts.

 

They do not have electric power steering pumps, the whole setup is electrical.

Higher voltages are more dangerous, but there is less loss in the transmission of power. No auto manufactutors have anything over 12volt systems, except the hybrids but they still have dual systems one 12 volt the other what ever they want 200+

 

i know the over all plan is for no direct mechanical linkage for steering, they also have the same plans for brakes & the shifter too along with some other changes.
the main reason the car makers are moving to the high voltage systems is for the lower current requirements.
the things in the works will make it more expensive & a lot more work to swap in a drive train from 1 of these cars into an older car, but in the long run i think it will be worth it.
there is 1 vehicle that has been out there for years that triggers the injectors with 115 volts DC

 

I think hundyas(whatever the spelling is)also use electric power steering.Why not try the elec smog pumps some cars now use instaed of EPS?

 

acualy the new hybrids are going to have all the accsories on a an electric motor, its gets about 20% better fuel econ,
i think its the new ford escape, but any way it should work fine besides you dont need much torque to turn the acc at idle speed but to run them at max rpm takes alot of power from your engine, car manufacturesr are lazy thats why cars are still just fancy covered wagons, they all still have 4 wheels !!!

when 3 is so much more efficient and faster


think t rex or bmw scorpion

 

You go ahead and ride your ATC, ill keep my ATV. Your method of deduction eludes even the greatest....