Outer Limits 4x4 Board

Beastmavster wrote:An electric supercharger could potentially work, but not the way these things are.


2400 watts (vaccum cleaner power) might get you somewhere... but 500 watts sure as hell wouldnt.


We've seen the leaf blower and that works. You need more airflow than the engine can make. Depending on the size of your engine, determines the needed airflow.

As to the argument about the drag due to the alternator meaning that you'd lose power, sorry but to my knowledge of car electonics that's total crap.

An alternator generates far more than 13.8-14.2V unregulated, so you're wearing the same frictional drain no matter what - just over 14 volts the excess is wasted in heat energy from the voltage regulator.

The regulator is there to prevent battery overcharing otherwise 18V would be quite likely at high rpm at most alternators.

Its not the Voltage its the AMPS.. Thats why on a lil old motor with a 35 amp alternator you could use one tiny lil v belt to spin it.. A GU with a 135amp alternator has two rather large Vbelts as more grip required at the pulley to keep the alternator spinning when it's working at it's maximum output ..

If not you would have energy for free .. a perpetual motion engine..

Beastmavster wrote:
As to the argument about the drag due to the alternator meaning that you'd lose power, sorry but to my knowledge of car electonics that's total crap.

.

Is that limited

Beastmavster wrote:An electric supercharger could potentially work, but not the way these things are.


2400 watts (vaccum cleaner power) might get you somewhere... but 500 watts sure as hell wouldnt.


We've seen the leaf blower and that works. You need more airflow than the engine can make. Depending on the size of your engine, determines the needed airflow.

As to the argument about the drag due to the alternator meaning that you'd lose power, sorry but to my knowledge of car electonics that's total crap.


An alternator generates far more than 13.8-14.2V unregulated, so you're wearing the same frictional drain no matter what - just over 14 volts the excess is wasted in heat energy from the voltage regulator.

The regulator is there to prevent battery overcharing otherwise 18V would be quite likely at high rpm at most alternators.

Unfortunately your on the wrong track . Its all about power conversion not volts. Watts is volts x amps less efficiency losses.

An alternator regulates its output voltage. The current can increase or decrease. If a load is applied that needs more current the alternator takes power from the motor. A heavilty loaded alt will slow engine down so more fuel is req to keep speed the same. (power loss) Just imagine its a pump, to pump more requires more input power or pump will slow down.

Using higher voltage motor and alt doesnt really help either as wattage (power) req is still the same. Less current but more volts = same watts.

Bazzle (simplistically speaking)

to add..

at 12v a 2400watt blower would draw 200amps which is far larger than any automotive one. you could fit a seperate alternator and wire that to the blower......but why bother, a belt is simpler, cheaper and LIGHTER.

also if you going to add a big alternator and motor why not just fit one of the motors and batteries off a hybrid. instead of useing to make boost just use it like a hybrid and add a bit of power directly to the motor and charge up batteries on the downhill.

love_mud wrote: Its not the Voltage its the AMPS.. Thats why on a lil old motor with a 35 amp alternator you could use one tiny lil v belt to spin it.. A GU with a 135amp alternator has two rather large Vbelts as more grip required at the pulley to keep the alternator spinning when it's working at it's maximum output ..

If not you would have energy for free .. a perpetual motion engine..

Nope. It's not free energy. You've paid for the energy in the alternator load on the crank, it's just what form you use the energy you're drawing off the engine.

You're just converting the alternator effort to heat if you're not using the electrical energy, and electrical energy if the demand is there.

Regardless if the demand is there, the alternator still turns and still generates the same current at the same rpm.


To draw an analogy. If you have a solar panel out in the sun, it's still generating electricity whether or not you have it connected to anything or not.

Beastmavster wrote: you're just converting the alternator effort to heat if you're not using the electrical energy, and electrical energy if the demand is there.

Regardless if the demand is there, the alternator still turns and still generates the same current at the same rpm.

Nup - no way.

Voltage yes.
Current no.

Amps will only be drawn when a load is connected.

Never seen a regulator that could dissapate 500+ watts.

Big Red Toy wrote:these electric superchargers work better with a 3 Farad flux capacitor across the terminals, stops voltage drop when they spool up

Ahh cool, where can I get a bonnet scoop big enough to hide the 3 Farad capacitor?

Beastmavster wrote:An electric supercharger could potentially work, but not the way these things are.

2400 watts (vaccum cleaner power) might get you somewhere... but 500 watts sure as hell wouldnt.

I have wondered this, I have a 1700w inverter and a 1300w Volta vacumn

You may need speed control I guess, unless you just kick it in at full pedal with a bypass valve.

If your altenator is only 45 Amps it's not going to draw any more power than if you had you headlights on highbeam & heater fan running flat chat, hardly enough to lose performance. It doesn't matter iff the supercharger is pulling 200A at the time if you have good batteries, the balance charge will just even out when your not on full boost.

What you are doing is trickle storing extra power to run the supercharger when it's not on song, then grabbing it in the 5-30 seconds you want it.
Even if the efficiency isn't as good as a regular turbo/supercharger, it would depend overall on how often you used it on boost, you could in theory run a mass oversized supercharger and just vary the boost ramping by computer control, therefore getting rid of low rpm lag and other problems you normally have trying to match a turbo to an engine.

Maybe the supercharger shown doesn't work, but the principle should.

Pulling up at the lights next to a ricer in a crappy 89 Patrol with the vacumn sound, Godfey's & Hoover stickers would be awesome

Beastmavster wrote:

love_mud wrote: Its not the Voltage its the AMPS.. Thats why on a lil old motor with a 35 amp alternator you could use one tiny lil v belt to spin it.. A GU with a 135amp alternator has two rather large Vbelts as more grip required at the pulley to keep the alternator spinning when it's working at it's maximum output ..

If not you would have energy for free .. a perpetual motion engine..

Nope. It's not free energy. You've paid for the energy in the alternator load on the crank, it's just what form you use the energy you're drawing off the engine.

You're just converting the alternator effort to heat if you're not using the electrical energy, and electrical energy if the demand is there.

Regardless if the demand is there, the alternator still turns and still generates the same current at the same rpm.


To draw an analogy. If you have a solar panel out in the sun, it's still generating electricity whether or not you have it connected to anything or not.

Umm, no. ever jump started a car with a little buzz box, i.e. alto, charade, etc. and noticed the idle drop, thats due to the extra draw on the alternator, this is why these things are useless, because the power consumed to spin the piece of crud is a further resistance on the crank and negates the benefit of the added pressure into the intake, i'd also like to see these things add a positive pressure to your intake considering you have to force more air in than the natural vacuum of the engine is sucking and then ADD a positive pressure.

cloughy wrote: Umm, no. ever jump started a car with a little buzz box, i.e. alto, charade, etc. and noticed the idle drop, thats due to the extra draw on the alternator, this is why these things are useless, because the power consumed to spin the piece of crud is a further resistance on the crank and negates the benefit of the added pressure into the intake, i'd also like to see these things add a positive pressure to your intake considering you have to force more air in than the natural vacuum of the engine is sucking and then ADD a positive pressure.

Yet somehow a little spinning set of blades driven by exhaust pressure can do this?

I you want to use a system like this on any car, then it needs dedicated battery/batteries to get any advantage.

Do the maths:

assume peak torque at 3000 rpm (best volumetric efficiency)

4 litre engine = 4 litres every 2 revs, swept volume -> 2 litres required per rev.

at say 7.5 psi boost = .5 atm

to calculate the volume of air required per minute: displacement per revolution x absolute pressure boost x req revs.

2 x 1.5 x 3000 = 9000 litres of air per minute required

average electric 16" fan moves 2100 l/min at 1 atm pressure, less than that at 1.5 atm required (ca 1500 l/min???).


Clearly would need a very high speed turbine as in the engine driven CAPA setups or a proper exhaust driven turbine. Anything electric is going to be massively geared up with huge mechanical losses involved.

I wonder if you could "drip feed" a bit of fuel into the turbine (exhaust) inlet of the turbo and hook it up to an igniter like they do in aircraft turbines, so you could "pre-spin" your turbo/supercharger reducing any lag to a minimum.

DAMKIA wrote:Do the maths:

assume peak torque at 3000 rpm (best volumetric efficiency)

4 litre engine = 4 litres every 2 revs, swept volume -> 2 litres required per rev.

at say 7.5 psi boost = .5 atm

to calculate the volume of air required per minute: displacement per revolution x absolute pressure boost x req revs.

2 x 1.5 x 3000 = 9000 litres of air per minute required

average electric 16" fan moves 2100 l/min at 1 atm pressure, less than that at 1.5 atm required (ca 1500 l/min???).


Clearly would need a very high speed turbine as in the engine driven CAPA setups or a proper exhaust driven turbine. Anything electric is going to be massively geared up with huge mechanical losses involved.

I wonder if you could "drip feed" a bit of fuel into the turbine (exhaust) inlet of the turbo and hook it up to an igniter like they do in aircraft turbines, so you could "pre-spin" your turbo/supercharger reducing any lag to a minimum.

So a leaf blower can work but a vacumn cleaner doesn't move enough air to create boost?

Rainbow Warrior wrote:

DAMKIA wrote:Do the maths:

assume peak torque at 3000 rpm (best volumetric efficiency)

4 litre engine = 4 litres every 2 revs, swept volume -> 2 litres required per rev.

at say 7.5 psi boost = .5 atm

to calculate the volume of air required per minute: displacement per revolution x absolute pressure boost x req revs.

2 x 1.5 x 3000 = 9000 litres of air per minute required

average electric 16" fan moves 2100 l/min at 1 atm pressure, less than that at 1.5 atm required (ca 1500 l/min???).


Clearly would need a very high speed turbine as in the engine driven CAPA setups or a proper exhaust driven turbine. Anything electric is going to be massively geared up with huge mechanical losses involved.

I wonder if you could "drip feed" a bit of fuel into the turbine (exhaust) inlet of the turbo and hook it up to an igniter like they do in aircraft turbines, so you could "pre-spin" your turbo/supercharger reducing any lag to a minimum.

So a leaf blower can work but a vacumn cleaner doesn't move enough air to create boost?

More than likely.............. (moving it across a decent pressure gradient)

DAMKIA wrote:I wonder if you could "drip feed" a bit of fuel into the turbine (exhaust) inlet of the turbo and hook it up to an igniter like they do in aircraft turbines, so you could "pre-spin" your turbo/supercharger reducing any lag to a minimum.

Thats an interesting idea...but I was wondering why an aircraft would need to pre-spin a turbo - would that only be necessary where there is a lot of on-off power required, like a race car? A plane would be running fairly constant RPM most of the time.

I kwow nothing about planes but am interested...

grazza wrote:

DAMKIA wrote:I wonder if you could "drip feed" a bit of fuel into the turbine (exhaust) inlet of the turbo and hook it up to an igniter like they do in aircraft turbines, so you could "pre-spin" your turbo/supercharger reducing any lag to a minimum.

Thats an interesting idea...but I was wondering why an aircraft would need to pre-spin a turbo - would that only be necessary where there is a lot of on-off power required, like a race car? A plane would be running fairly constant RPM most of the time.

I kwow nothing about planes but am interested...

Talking about the "jet engines" not turbocharged piston engines.

It is how they get them started in the first place. Spin them up with a "starter motor", start the igniters, add fuel, and watch the revs rise untill the compressor is efficient enough to ignite the fuel by compression alone.

DAMKIA wrote:Maybe the idea would be to power it from a second unregulated alternator, then as the engine speed increases, the voltage/current increase and therefore the total power going into the electric blower increases.

rather than having a second unregulated alternator, why not just have the belt driving a turbine which drives the air into the intake manifold? of course, that's what the existing supercharger is doing

talking about "unregulated" voltage, is it possible to connect a separate set of bridge rectifiers with capacitors directly to the alternator AC output and the DC output of the rectifier section connected to the electric fan (supercharger). If the alternator outputs 10V at idle and 16 volt ac max, the rectified output would have 1.414 times, so 14V dc to 22V dc

ps: if that supercharger really draws 40amps (a) the rectifiers could be bulky (b) the 0.414X peak surge may be reduced

metal wrote:

DAMKIA wrote:Maybe the idea would be to power it from a second unregulated alternator, then as the engine speed increases, the voltage/current increase and therefore the total power going into the electric blower increases.

rather than having a second unregulated alternator, why not just have the belt driving a turbine which drives the air into the intake manifold? of course, that's what the existing supercharger is doing

And typically gives bugger-all boost at idle. Theoretically, an electric supercharger can give full boost at idle.

metal wrote:ps: if that supercharger really draws 40amps (a) the rectifiers could be bulky (b) the 0.414X peak surge may be reduced

40A? That's a small alternator by today's standards - you don't need large diodes, you only need good heatsinking.

The theoretical benefit of electric supercharging is superior response, particularly at/near idle. Think of instantaneous boost, for short duration. If you want full boost for extended duration the solution is well known. It's the transition from no boost - full boost for which electric holds the potential, so use batteries to supply the power, and a conventional charging system to replenish the charge. Instantaneous boost when you need it, without excessive power drag when you don't.

None of this is rocket science. The only piece missing is a suitable electric motor:

High power capacity to deliver the extreme turbine acceleration required.
Small/light enough to be practical for a commuter sized vehicle/engine.
Robust enough to cope with the heat and vibrations.

I recently read of a hybrid electric/exhaust turbo-charger - uses an electric motor to provide initial turbine acceleration, then functions as a normal turbo once up to boost. I thought it looked quite promising.

Cheers,

Scott

-Scott- wrote:

metal wrote:
ps: if that supercharger really draws 40amps (a) the rectifiers could be bulky (b) the 0.414X peak surge may be reduced

40A? That's a small alternator by today's standards - you don't need large diodes, you only need good heatsinking.

The theoretical benefit of electric supercharging is superior response, particularly at/near idle. Think of instantaneous boost, for short duration. If you want full boost for extended duration the solution is well known. It's the transition from no boost - full boost for which electric holds the potential, so use batteries to supply the power, and a conventional charging system to replenish the charge. Instantaneous boost when you need it, without excessive power drag when you don't.

None of this is rocket science. The only piece missing is a suitable electric motor:

Hey, mate

why bother with DC motor?? I just thought about AC motor, say 12V to 24V A/C motor (with the right RPM, torque, maybe a small gear box), directly connected to the alternator output, no diodes, no caps, no regulators, no heatsinks... Actually, as mentioned in previous post, the power consumption of the motor reduces the heat disipation of the voltage regulator So the energy efficiency of using an AC motor could be even higher than the regular supercharger as the AC motor utilised wasted energy (excess output of the alternator)

Then the next question is the AC frequency of the car alternator output? The normal home powerline A/C frequency is 50hz or 60hz, depending on whether you are in UK, USA, Australia, NZ, Japan, etc.

So anybody hav any ideas what the A/C frequency of the car alternator AC output? Is it standardised?

Beastmavster wrote:
Nope. It's not free energy. You've paid for the energy in the alternator load on the crank, it's just what form you use the energy you're drawing off the engine.

You're just converting the alternator effort to heat if you're not using the electrical energy, and electrical energy if the demand is there.

Regardless if the demand is there, the alternator still turns and still generates the same current at the same rpm.

IMHO, and to my basic electronic knowledge, the alternator output A/C in a range, say, 12V to 17V ac, depending on the RPM of the alternator thus the RPM of the engine.

So say if 60 amps at 12V DC are consumed by the car via the regulators, and if the alternator outputs 16V at a particular RPM of the engine, 4Vx60amp (240W) is wasted by the regulator as heat (forget about 1.414 peak surge during rectification for the time being)

So, electrically energy IS wasted during the regulation process, the higher the amperage drawn by the car the more energy is wasted. Also the higher RPM of the wngine, the more energy is wasted.

But, on the other hand, if a car normally draws 100amp, and if the alternator outputs 16V at most, 400W (4Vx100amp) is not that much power for an electrical supercharger...well, better than wasted anyway

and the above deduction(?) is based on the assumption that after the supercharger motor (DC or AC) has been connected to the alternator (DC motor via rectiifier), the output voltage of the alternator ranges between 12~13V rather than the original 12~16V, and this reduce the heat dissipation of the regulator

Beastmavster wrote:

love_mud wrote: Its not the Voltage its the AMPS.. Thats why on a lil old motor with a 35 amp alternator you could use one tiny lil v belt to spin it.. A GU with a 135amp alternator has two rather large Vbelts as more grip required at the pulley to keep the alternator spinning when it's working at it's maximum output ..

If not you would have energy for free .. a perpetual motion engine..

Nope. It's not free energy. You've paid for the energy in the alternator load on the crank, it's just what form you use the energy you're drawing off the engine.

You're just converting the alternator effort to heat if you're not using the electrical energy, and electrical energy if the demand is there.

Regardless if the demand is there, the alternator still turns and still generates the same current at the same rpm.


To draw an analogy. If you have a solar panel out in the sun, it's still generating electricity whether or not you have it connected to anything or not.

I agree with the solar panel anaolgy .. and I would agree with the alternator to if it used pemenant magents, but an ac voltage is developed and rectified dc. this voltage is compared to the battery voltage and determines the current through the rotor. if the battery voltage is lower than the alternator voltage, more current is passed through the rotor thus increaseing the magnetic field and creates a larger alternator voltage. if the battery voltage is higher, less current through the rotor decreases the alternator voltage.

So when the magentic field is increased the alternator becomes much harder to turn

DAMKIA wrote:

Rainbow Warrior wrote:

DAMKIA wrote:Do the maths:

assume peak torque at 3000 rpm (best volumetric efficiency)

4 litre engine = 4 litres every 2 revs, swept volume -> 2 litres required per rev.

at say 7.5 psi boost = .5 atm

to calculate the volume of air required per minute: displacement per revolution x absolute pressure boost x req revs.

2 x 1.5 x 3000 = 9000 litres of air per minute required

average electric 16" fan moves 2100 l/min at 1 atm pressure, less than that at 1.5 atm required (ca 1500 l/min???).

Clearly would need a very high speed turbine as in the engine driven CAPA setups or a proper exhaust driven turbine. Anything electric is going to be massively geared up with huge mechanical losses involved.

I wonder if you could "drip feed" a bit of fuel into the turbine (exhaust) inlet of the turbo and hook it up to an igniter like they do in aircraft turbines, so you could "pre-spin" your turbo/supercharger reducing any lag to a minimum.

So a leaf blower can work but a vacumn cleaner doesn't move enough air to create boost?

More than likely.............. (moving it across a decent pressure gradient)

I don't know the speed of a vacumn cleaner motor, sounds pretty high, but I don't believe thay have gearboxes, so I ssume it's 3000rpm.

Hmm, 3000 rpm is the speed of a normal 240vAC motor, a vacumn cleaner motor is rated at say 1200w, 5 amps. 1200w running through an inverter need 12v at about 120A, no problem for a couple of good winching batteries. Ok so we are using nearly a kw to create extra boost, which should result in more than a kw output increase. And if you put an industrial speed controller in, you could pick your boost at any rpm you liked, though this could play havoc if you didn't also have your fuel mixtures adjusting accordingly.

Not sure if you can get more than 3000rpm out of an electric motor I suspect this is because of the 50Hz limitation. On the other hand we could use a 3 phase motor & industrial Variable Speed Drive many have 240v input and 3 phase output and can put out maybe 120Hz, but 3 phase motors are only 1450rpm so back to 3000rpm on a motor not mechanically designed for it.

So we need a gearbox and sorta guessing from what I see on roots blowers 1:2 - 1:3 ratio? But why mechanically gear the shaft, when you can stuff around with the fan design / size instead.

Anyone know what speed a turbocharger spins at in hard usage? I think 10,000-15,000 rpm?

What happens to a motor at low rpm when you shove under boost a heap of extra fuel / air mix, in the right ratio's? Something a normal supercharger/ turbocharger can't do, but electic running off batteries could.

Normally turbo / supercharging is a compromise on high / low rpm sizing, with this I supect you would calculate the size based on the largest size you need at maximum rpm.

Being bigger probbaly means you could get enough suck through to keep the car running ok with the supercharger off & freespinning too I suspect.

Or could we just store the compressed air in a tank in advance off an engine driven high pressure compressor? Can you store air at 500psi?Bloody big tank, big solenoid & big hoses

The newer electric superchargers run brushless motors at 50,000rpm.

From the other thread if anyone missed it:
http://www.visteon.com/products/automotive/vtes.shtml

Perhaps reading this document (sorry, PDF) will illustrate that some progress is happening: http://www.visteon.com/utils/whitepaper ... 1_0523.pdf

Rainbow Warrior wrote:[Anyone know what speed a turbocharger spins at in hard usage? I think 10,000-15,000 rpm?

You're out by a factor of 10. Try 100,000 rpm plus.

10k rpm is pretty easy for a small DC motor, you can push them much higher for short durations - but 100k rpm is a huge ask, particularly if the object is to get there quickly. And that's without considering the load of the fan blades actually compressing air.

Scott

Check out what this guy has done with a turbo... Wonder if it could be plumbed into a car..

http://www.powerlabs.org/turbine.htm

check out the vids

Patroler wrote:Check out what this guy has done with a turbo... Wonder if it could be plumbed into a car..

http://www.powerlabs.org/turbine.htm

check out the vids

looks like poor mans ver of the early jet engines england made back in WW2. there is a reason they dropped that design for the axil design the germans had.