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electric supercharger 7
- Thread starter ed911
- Start date
patprimmer
New member
Warpspeed
The following is from my post 20/06/06
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The following is from my post 20/06/06
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
I just though I would emphasize and expand on that idea a bit Pat.
Compounding still remains relatively unknown, even though the idea has been around for a very long time.
Many if not all long distance road diesels typically run a turbocharger compounded with a roots scavenge blower. They not only have plenty of torque !!! but the specific power is not too bad either.
The same idea works wonderfully well on a four stroke gasoline engine.
Compounding still remains relatively unknown, even though the idea has been around for a very long time.
Many if not all long distance road diesels typically run a turbocharger compounded with a roots scavenge blower. They not only have plenty of torque !!! but the specific power is not too bad either.
The same idea works wonderfully well on a four stroke gasoline engine.
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This has been one of the most entertaining technology to watch progress and squirm over the years. The obvious (or should be) issue of power vs. required work of electric air chargers has been bent, distorted, manipulated and flat out ignored to push allot of agenda depending on the number of investors and or customers needing to be fleeced. The near critical mass of 42V standards and implementation and then collapse, left allot of people in holding patterns with some reasonable systems that started to look good at 42V, but no way at 12V. Hybrid is the only daylight most of those systems will see in the near future until 42V is back on (Betamax = better technology without critical mass). The real goods in elec superchargers is the fact that it isn't bound by exhaust volume or RPM and can harmonize with critical control strategies not available to turbo/supercharger devices (VNT is closest). Vehicles that operate one day with a full payload and then dead head the next are difficult to resolve for emissions and power in both modes, and is one example of what makes the E charger so sought after. Since you can plan on 20 to 30 hp to drive any of today's best compressors to the mass flow requirements to replace a turbo or s/charger, you will still have the same parasitic lose or more, so in the long run the real upside to E-charging is its on command mode of operation. If this on command - as needed attribute was not inherent to the E charger, it would not be continually reinvented. My company spent about five years working with Dave Kapich, a brilliant guy (Kapich Engineering) that holds the patents for a hydraulically driven supercharger (HydraCharger) for use in the automotive aftermarket and learned just how important the on demand attribute is and will be from here on. The Hydracharger is an on demand device much like a E charger except it is a centrifugal compressor drive by a hydraulic turbine at 2000 to 3000 psi that is controlled via an electro-proportional valve from the ECU. What we learned was we probably would never make more peak power than turbo or supercharger but we could control throttle response, drivability, and emissions with much greater accuracy and with a much smaller engine. Throttle rate and jerk can be interpreted more closely as "driver intent" instead of "engine requirement" as the engine torque can now be slaved more accurately to the driver intent based on throttle rate change nuances. Many more boost control strategies are possible for on demand boosting like maintaining a mapped delta P across the throttle, based on, rpm and throttle rate where say a .5psi delta is maintained at the throttle during cruise and varied based on throttle opening rate up to the peak boost limit for example. The Hydracharger is now being used as an alternative to E charging in diesel turbo assist. Until motor armatures are developed that can spin 50K RPM, develop 20+HP on 12 to 24V, and operate day to day at -40C to 180C E charging will not be a big player. Looking forward to a few more years of entertainment on this one!
Interesting jimwolf!
That again mentions something that is cris-crossed in this thread, which is duty cycle. "On-demand" means just that; short periods of boost for acceleration, not prolonged or continuous operation to make up for cubic inches. Construction and consumption wise, they really are apples and oranges. Nothing determines parameters or feasability more than duty cycle and defining the purpose.
Using hydraulics was a bit crazy years ago but not any more. It makes sense for intermittant or continuous operation. Good thing we invented accumulators, otherwise we would have to deal with hydro-lag.
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- #25
globi5
Mechanical
- Oct 10, 2005
- 281
If VW would electrically drive a supercharger to charge its 1.4 l engine Twincharger below 2500 rpm it would not require more than 4kW at 1 bar (P = approx. p*V/t). It might not even be considerably heavier than the mechanical version since it can use a lighter, more efficient centrifugal supercharger without parasitic loss, which since it doesn't need a mechanical connection to the engine, can be placed just next to the batteries (short thick copper cables). To take care of the short current bursts, this car could run with two 12V batteries. One 12V battery would still be parallel to the entire system and the second 12V battery would be in series to the first and run the supercharger on demand. The alternator would be larger (24V), charge both batteries and be turned off at full throttle (no parasitic loss) and run at full load when decelerating (and even regenerate some of the braking energy). With this system it is not possible to run full throttle for more than a few seconds, simply because the larger turbo is eventually up and running. And therefore the electric energy needed to run the system is relatively low (no need for a big and heavy battery pack).
Besides the Prius has a 50kW electric motor and a 12V system. Granted it also has some more powerful NiMH batteries as well, but obviously providing 50kW even in a relatively small car of electric power is not an issue. And running over 200V in a car with a 12V system is apparently not a big problem either. Otherwise we should occasionally see a Prius on an emergency lane.
Also BMW showed that turbosteamer concept not too long ago. If the turbosteamer would run an electric generator it could provide sufficient electric energy to run an electric supercharger. Besides, power requirements of electric supercharger are high, but energy requirements aren't really that high - at least not in countries with speed limits, curves and traffic jams (which I believe most have). So there's not necessarily a need to carry a lot of batteries to provide enough electric power for constant full throttle operation.
I believe an electric supercharger has some merits and it might be an alternative to hybrids. Of course, not quite as efficient but it wouldn't come with the mass penalty of a hybrid and therefore make an option for a more efficient sportscar.
Last but not least: Superchargers and regenerative braking systems are prohibited in F1.
Besides the Prius has a 50kW electric motor and a 12V system. Granted it also has some more powerful NiMH batteries as well, but obviously providing 50kW even in a relatively small car of electric power is not an issue. And running over 200V in a car with a 12V system is apparently not a big problem either. Otherwise we should occasionally see a Prius on an emergency lane.
Also BMW showed that turbosteamer concept not too long ago. If the turbosteamer would run an electric generator it could provide sufficient electric energy to run an electric supercharger. Besides, power requirements of electric supercharger are high, but energy requirements aren't really that high - at least not in countries with speed limits, curves and traffic jams (which I believe most have). So there's not necessarily a need to carry a lot of batteries to provide enough electric power for constant full throttle operation.
I believe an electric supercharger has some merits and it might be an alternative to hybrids. Of course, not quite as efficient but it wouldn't come with the mass penalty of a hybrid and therefore make an option for a more efficient sportscar.
Last but not least: Superchargers and regenerative braking systems are prohibited in F1.
One thing that has not been mentioned is the extra power required to accelerate an electrically driven centrifugal supercharger up to boost producing Rpm.
If it takes many horsepower to run it continuously at final boost pressure, it is going to take considerably more power to accelerate both the motor itself, and the blower rotor from stationary up to perhaps 100,000 Rpm+ in a sufficiently short time to be effective.
Fair enough your rotor can be aluminum, but your motor still needs to be a copper and iron rotor of some sort, and reducing motor mass and inertia is not going to be so easy. To get the rotor acceleration, raw Kw are going to be required.
That may impose a huge extra electrical power penalty for lag free on/off driving.
But there is another quite different problem....
At least with engines that have few cylinders, there will be an engine Rpm below which very high boost pressures are going to cause unacceptable crankshaft speed fluctuations that the flywheel is not going to be able to cope with. This may cause some small drama in the following transmission. The idea of massive low Rpm boost sounds attractive, but it can create problems elsewhere.
A properly sized screw supercharger can readily produce full rated boost pressure at or even below 2,000 engine Rpm. That may be about as low as you would really want to go for the reasons stated above. Adding electric drive to the supercharger to get even more low Rpm boost may just not be practical.
I read somewhere that Jaguar had to increase flywheel weight on their V8 when they added the Eaton supercharger. Apparently there were low speed torque fluctuations not present in the normally aspirated version of that engine. And that was with an eight cylinder engine and a roots blower.
The problem is likely to be far worse on a four cylinder engine with a screw blower, (or an electric centrifugal).
If it takes many horsepower to run it continuously at final boost pressure, it is going to take considerably more power to accelerate both the motor itself, and the blower rotor from stationary up to perhaps 100,000 Rpm+ in a sufficiently short time to be effective.
Fair enough your rotor can be aluminum, but your motor still needs to be a copper and iron rotor of some sort, and reducing motor mass and inertia is not going to be so easy. To get the rotor acceleration, raw Kw are going to be required.
That may impose a huge extra electrical power penalty for lag free on/off driving.
But there is another quite different problem....
At least with engines that have few cylinders, there will be an engine Rpm below which very high boost pressures are going to cause unacceptable crankshaft speed fluctuations that the flywheel is not going to be able to cope with. This may cause some small drama in the following transmission. The idea of massive low Rpm boost sounds attractive, but it can create problems elsewhere.
A properly sized screw supercharger can readily produce full rated boost pressure at or even below 2,000 engine Rpm. That may be about as low as you would really want to go for the reasons stated above. Adding electric drive to the supercharger to get even more low Rpm boost may just not be practical.
I read somewhere that Jaguar had to increase flywheel weight on their V8 when they added the Eaton supercharger. Apparently there were low speed torque fluctuations not present in the normally aspirated version of that engine. And that was with an eight cylinder engine and a roots blower.
The problem is likely to be far worse on a four cylinder engine with a screw blower, (or an electric centrifugal).
globi5
Mechanical
- Oct 10, 2005
- 281
To overcome the supercharger's inertia one can use capacitors.
Small diesel engines have probably high crankshaft fluctuations as well (low rpm and high cylinder pressure). This just means that engines need to be designed accordingly. As far as I know the VW 1.4l engine with its Twincharger is quite different to the 1.4l NA engine as well.
I do see that there's still development work to be done. And it is not free, but it is feasible with the technology available today. If gas prices continue to rise, this option will become more attractive since it is one way apart from many others to make engines more efficient.
Btw here's article about eBooster an electric supercharger from BorgWarner Turbosystem:
Small diesel engines have probably high crankshaft fluctuations as well (low rpm and high cylinder pressure). This just means that engines need to be designed accordingly. As far as I know the VW 1.4l engine with its Twincharger is quite different to the 1.4l NA engine as well.
I do see that there's still development work to be done. And it is not free, but it is feasible with the technology available today. If gas prices continue to rise, this option will become more attractive since it is one way apart from many others to make engines more efficient.
Btw here's article about eBooster an electric supercharger from BorgWarner Turbosystem:
patprimmer
New member
I'm with Warpspeed.
Unless the centrifugal blower is kept wound up to maintain boost, there will still be lag as the electric motor and blower accelerate from rest.
If it is kept wound up to maintain pressure until the turbo takes over, there will be considerable time when it is running against a part open or closed throttle, so it is in a ready state to overcome lag.
If I where to do this tomorrow, I would be looking at smallish belt driven screw blowers fed from a biggish turbo, maybe with a bypass valve around the blower, depending on whether it became a choke point at higher speeds.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Unless the centrifugal blower is kept wound up to maintain boost, there will still be lag as the electric motor and blower accelerate from rest.
If it is kept wound up to maintain pressure until the turbo takes over, there will be considerable time when it is running against a part open or closed throttle, so it is in a ready state to overcome lag.
If I where to do this tomorrow, I would be looking at smallish belt driven screw blowers fed from a biggish turbo, maybe with a bypass valve around the blower, depending on whether it became a choke point at higher speeds.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
In my system I used a roots blower with an air bypass system fitted fitted around it. The bypass was held fully open at idle and light throttle, and progressively closed with increasing throttle opening. Flat out, the bypass was shut tight.
The goal was to completely unload the supercharger at idle and light throttle. With a fully open air bypass, it is like having the rotors spinning in free air with no outer casing. There is almost no parasitic power loss, very little noise and almost no heat generated that way. It will considerably improve fuel consumption, and the supercharger runs much cooler.
The pneumatically controlled bypass consisted of a modified external turbocharger wastegate. The control diaphragm was connected with two hoses directly across the throttle body. It will be appreciated that the differential pressure drop across the throttle holds the wastegate open against it's spring.
This is really the same as manifold vacuum (in the unboosted condition). But because it is the differential pressure directly across the throttle, the control pressure drops to zero with a wide open throttle, no matter how high the boost pressure rises.
Choice of spring rate and free length in the wastegate enables you to tailor how the bypass closes with increased throttle opening. This is a wonderful tool for adjusting drivability because it is load sensitive. Where and how rapidly boost rises with increasing throttle opening can be very smooth and precise indeed.
The final step is as Pat says, add a very large turbocharger to the whole system. That will do wonders for the top end airflow.
In order for a positive displacement supercharger to create boost pressure, the swept volume of the supercharger must be significantly higher than that of the engine. At higher Rpm it can never really become a restriction. The Ve of both supercharger and engine will fall with Rpm, but the turbo will more than make up for that.
As I said earlier I developed this fairly unique bypass system myself a very long time ago, and was absolutely delighted with the results. The blower bypass system is the key to reducing light throttle parasitic blower drive loss, and is a powerful tool for adjusting throttle feel and drivability. It also eliminates the need for a supercharger drive clutch, (which can add a whole lot of other problems).
I would be very surprised if an electric supercharger could beat it when all aspects are taken into account.
The goal was to completely unload the supercharger at idle and light throttle. With a fully open air bypass, it is like having the rotors spinning in free air with no outer casing. There is almost no parasitic power loss, very little noise and almost no heat generated that way. It will considerably improve fuel consumption, and the supercharger runs much cooler.
The pneumatically controlled bypass consisted of a modified external turbocharger wastegate. The control diaphragm was connected with two hoses directly across the throttle body. It will be appreciated that the differential pressure drop across the throttle holds the wastegate open against it's spring.
This is really the same as manifold vacuum (in the unboosted condition). But because it is the differential pressure directly across the throttle, the control pressure drops to zero with a wide open throttle, no matter how high the boost pressure rises.
Choice of spring rate and free length in the wastegate enables you to tailor how the bypass closes with increased throttle opening. This is a wonderful tool for adjusting drivability because it is load sensitive. Where and how rapidly boost rises with increasing throttle opening can be very smooth and precise indeed.
The final step is as Pat says, add a very large turbocharger to the whole system. That will do wonders for the top end airflow.
In order for a positive displacement supercharger to create boost pressure, the swept volume of the supercharger must be significantly higher than that of the engine. At higher Rpm it can never really become a restriction. The Ve of both supercharger and engine will fall with Rpm, but the turbo will more than make up for that.
As I said earlier I developed this fairly unique bypass system myself a very long time ago, and was absolutely delighted with the results. The blower bypass system is the key to reducing light throttle parasitic blower drive loss, and is a powerful tool for adjusting throttle feel and drivability. It also eliminates the need for a supercharger drive clutch, (which can add a whole lot of other problems).
I would be very surprised if an electric supercharger could beat it when all aspects are taken into account.
The 92 Series Detroit Diesels have used blower bypass valves for many years on their Roots type blowers. They work just the opposite. Closed at idle and light throttle and opened up with more turbo boost. Fully open at full turbo boost. Seems more sensible as it eliminates parasitic drive losses at high speeds and does not require an oversized turbo. Throttle response, driveability, and mileage are always maximized.
This setup could work well with a non-centrifugal electric blower.
globi5
Mechanical
- Oct 10, 2005
- 281
As I said before, the lag issue can be solved with capacitors. Acceleration is a question of power and as long as power is only needed for a very short time (less than a second) it can be provided with capacitors mounted close to the supercharger (short cables).
In this particular case if you go on page 16 of this paper, it only takes 0.4s to reach 60,000rpm (without capacitors).
So it is an issue that can be solved.
An electric powered roots supercharger would work as well. But centrifugal superchargers have the advantage of being lighter and more efficient and unfortunately the disadvantage they don't produce boost at low rpms. If the supercharger is independent of engine rpm this is not an issue anymore.
Btw capacitor technology is also evolving:
In this particular case if you go on page 16 of this paper, it only takes 0.4s to reach 60,000rpm (without capacitors).
So it is an issue that can be solved.
An electric powered roots supercharger would work as well. But centrifugal superchargers have the advantage of being lighter and more efficient and unfortunately the disadvantage they don't produce boost at low rpms. If the supercharger is independent of engine rpm this is not an issue anymore.
Btw capacitor technology is also evolving:
globi5
Mechanical
- Oct 10, 2005
- 281
An electric supercharger has the advantage of no parasitic loss and re-use decelerating energy (regenerative braking).
If maximum efficiency is the goal, an electric supercharger has definitely an edge over a mechanical system.
If maximum power is the goal, possibly not.
If maximum efficiency is the goal, an electric supercharger has definitely an edge over a mechanical system.
If maximum power is the goal, possibly not.
Fabrico, I am not at all familiar with the scavenge blower system fitted to Detroit two stroke diesels, but they are rather different to gasoline engines.
The main difference as you know, is that gasoline engines are throttled, and diesels are not.
With a gasoline engine equipped with a positive displacement supercharger, you quite obviously cannot just throttle the air at the supercharger outlet. When you close the throttle the pressure spike would almost certainly burst or break something. Airflow is just not controllable after the blower.
Throttling the air at the blower intake has one very serious disadvantage. At small throttle openings the supercharger behaves like a massive vacuum pump. It sucks furiously against the closed throttle. The supercharger will consume a surprisingly high drive power in that mode of operation, it will also run very hot and be objectionably noisy.
Every supercharged production car that I am aware of has a bypass system of some type fitted, and it is always kept open at idle and light throttle highway. Interestingly almost none of the homemade hot rod engines bother fitting a bypass, but usually they are not the least bit interested in fuel economy or light throttle blower noise.
If a remote air/air intercooler is being used with long pipework, fitting the throttle to the blower intake is just not going to work. Throttle response will be horrible to the point of the vehicle being undrivable. With a modern EFI vehicle, the throttle CAN be placed after a positive displacement supercharger if a suitable bypass system is used. But without a bypass it is just not possible.
For the very best results, run EFI, a supercharger bypass, an intercooler, and individual throttle bodies mounted as close to the cylinder head as possible. (With or without a turbo as well).
Diesel engines, especially two stroke diesel engines are a whole different ball game.
The main difference as you know, is that gasoline engines are throttled, and diesels are not.
With a gasoline engine equipped with a positive displacement supercharger, you quite obviously cannot just throttle the air at the supercharger outlet. When you close the throttle the pressure spike would almost certainly burst or break something. Airflow is just not controllable after the blower.
Throttling the air at the blower intake has one very serious disadvantage. At small throttle openings the supercharger behaves like a massive vacuum pump. It sucks furiously against the closed throttle. The supercharger will consume a surprisingly high drive power in that mode of operation, it will also run very hot and be objectionably noisy.
Every supercharged production car that I am aware of has a bypass system of some type fitted, and it is always kept open at idle and light throttle highway. Interestingly almost none of the homemade hot rod engines bother fitting a bypass, but usually they are not the least bit interested in fuel economy or light throttle blower noise.
If a remote air/air intercooler is being used with long pipework, fitting the throttle to the blower intake is just not going to work. Throttle response will be horrible to the point of the vehicle being undrivable. With a modern EFI vehicle, the throttle CAN be placed after a positive displacement supercharger if a suitable bypass system is used. But without a bypass it is just not possible.
For the very best results, run EFI, a supercharger bypass, an intercooler, and individual throttle bodies mounted as close to the cylinder head as possible. (With or without a turbo as well).
Diesel engines, especially two stroke diesel engines are a whole different ball game.
Warpspeed,
Your compassion for your invention is understandable, however, the arrangement you envision for the system I mention is not. All production, non-production, bypass, or non-bypass supercharged gasoline engines are throttled without significant problem. To my knowledge, none of them are throttled at the supercharger output. For some reason yours and everyone else’s blowers are throttleable at the intake, but mine is not. I assure you, the system I mentioned does not turn into a massive, furiously sucking, power draining, overheating, noisy, breaking or bursting monster, as you suggest. This is especially true at idle and low to moderate speeds, which is where the blower mainly operates.
Supercharged engines are famous for excellent throttle response, with or without a turbocharger. Of course this can only happen with any bypass closed.
You have suggested how well “compounding” would work on various occasions. Would your compounded system include the use of long piping, a remote air/air intercooler, and the other calamities you mentioned above? How would you handle throttling of the compounded system you promote?
Reliance on a Roots type blower for medium to high speed engine output is favorable to power but not significant efficiency. The system I mention not only bypasses at cruise but accepts a fairly well matched volume of air from the turbo, thus letting the blower virtually coast. At cruise, there is very little heat generated or mechanical power consumed, by the blower. Air from the turbo suffers little impedance by the blower. Closing the bypass at higher speeds compounds boost and makes significantly more power available in that range as well. Inter-cooling is done directly under the blower and has no air piping.
Please note, my post above meant to say “small centrifugal” blower instead of “non-centrifugal” blower. This is roughly one half of a turbo charger and can spool up immediately. An electric Roots type blower or geared Mcculloch centrifigual type are not on the menu. I would also question the practicality of any continuous electric blower.
In favor of your mentions of compounding, the electric "turbo" system I experimented with was on this same type of engine. This means an electric powered air pump pushing into a compounded system. It was not overly complicated, and except for electrical demand, worked flawlesly. The electrical demand was not way off, but just past practical. Another hurdle is that a 2-stroke needs more air than a similar size/speed 4-stroke. This alone could put electrial demand back in the practical range.
globi5, you are probably right about capacitors doing a great job of powering or helping to power an on-demand blower. Capacitors charge differently than batteries which might open new doors to regenerative or alternate sources of electircal power.
Well, all I can say then is Jaguar, Mercedes Benz, Toyota, and GM must have all got it totally wrong. Even Eaton must be wasting their time when they build a bypass butterfly right into the blower casing in some models, and a rear bolt on bypass butterfly assembly in other models.
As I said EVERY production supercharged car I am aware of uses an effective bypass system, and it works exactly as I described, usually controlled by the ECU. It is certainly not my invention, but a standard requirement for any properly designed production road supercharger system.
I am well aware that hot rodders and drag racers have been bolting GM blowers onto the tops of Chev (and other)engines for around sixty years, with massive carbies mounted on top. They work fine for what they are required to do. Not a bypass system in sight there anywhere either.
But you have never, and will never see anything like that on a 2006 model standard factory production car that has to meet acceptable small throttle fuel economy and NVH requirements.
And trust me, a downstream butterfly on a positive displacement supercharger WILL break something when you snap the throttle shut to change gear at 6,500 Rpm.
The very small mass airflow at light throttle, passing through a remote intercooler and long interconnecting pipework offers almost unmeasurable pressure drop and is not a problem. But the throttle absolutely must be located reasonably close to the engine. It can be located before or after the blower, as long as there is a bypass system fitted.
Study any supercharged production car and see how it is done. There are plenty of wide design variations, but they all have a blower bypass system fitted, every single one.
As I said EVERY production supercharged car I am aware of uses an effective bypass system, and it works exactly as I described, usually controlled by the ECU. It is certainly not my invention, but a standard requirement for any properly designed production road supercharger system.
I am well aware that hot rodders and drag racers have been bolting GM blowers onto the tops of Chev (and other)engines for around sixty years, with massive carbies mounted on top. They work fine for what they are required to do. Not a bypass system in sight there anywhere either.
But you have never, and will never see anything like that on a 2006 model standard factory production car that has to meet acceptable small throttle fuel economy and NVH requirements.
And trust me, a downstream butterfly on a positive displacement supercharger WILL break something when you snap the throttle shut to change gear at 6,500 Rpm.
The very small mass airflow at light throttle, passing through a remote intercooler and long interconnecting pipework offers almost unmeasurable pressure drop and is not a problem. But the throttle absolutely must be located reasonably close to the engine. It can be located before or after the blower, as long as there is a bypass system fitted.
Study any supercharged production car and see how it is done. There are plenty of wide design variations, but they all have a blower bypass system fitted, every single one.
GregLocock
Automotive
globi5 (Mechanical) 7 Jul 06 11:44
Again the Prius has regenerative braking but it does not have a 42V system. It has 12V battery and a 12V system like every other car. "
It has a 200 V (ish) battery to handle the regen. I find your statement disingenuous at best.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
Again the Prius has regenerative braking but it does not have a 42V system. It has 12V battery and a 12V system like every other car. "
It has a 200 V (ish) battery to handle the regen. I find your statement disingenuous at best.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
Warpspeed, what is your point? Do you really read other's posts? Is no one allowed to talk about different methods or ideas?
The only one who ever mentioned anything about using a downstream throttle is you.
The only one saying anything about popularity, necessity, or location of bypass valves is you.
The only one arguing their system is better is you.
You deny it is at all your invention yet before:
Again, compassion for something you believe in is understandable, but it should not get in the way of letting others discuss alternative ideas and taking the time to hear what they are saying.
The only one who ever mentioned anything about using a downstream throttle is you.
The only one saying anything about popularity, necessity, or location of bypass valves is you.
The only one arguing their system is better is you.
You deny it is at all your invention yet before:
Again, compassion for something you believe in is understandable, but it should not get in the way of letting others discuss alternative ideas and taking the time to hear what they are saying.
globi5
Mechanical
- Oct 10, 2005
- 281
Greg Locock, the point was that you don't need a 42V system to provide more electric power. The 12V light bulb doesn't care if there's an electric motor running seperately on a higher voltage. Actually I already posted before that the Prius has a seperate battery to provide electric power for its 50kW electric motor. However, and this is the crucial point, the entire rest of the car still runs on a 12V system.
The question I answered was whether electric powered superchargers are feasible and whether they have merits. The Prius shows that it is possible to provide a lot of electric power reliably without switching to a general 42V system.
And again electric superchargers have merits because:
* no parasitic loss.
* be able to take advantage of a centrifugal supercharger (lighter and higher efficiency).
* no frictional losses when cruising.
* more freedom about where to place supercharger.
* operate supercharger at any speed independent from engine speed.
* can take advantage of regenerative braking.
Nobody claims that electric driven supercharger don't have disadvantages as well. But again that it is technically feasible and that it has advantages compared to a mechanical system, especially when it comes down to fuel saving measures, is obvious. And I also believe if Turbo system companies like BorgWarner are working on it, it can't be such a ridiculous concept after all.
The question I answered was whether electric powered superchargers are feasible and whether they have merits. The Prius shows that it is possible to provide a lot of electric power reliably without switching to a general 42V system.
And again electric superchargers have merits because:
* no parasitic loss.
* be able to take advantage of a centrifugal supercharger (lighter and higher efficiency).
* no frictional losses when cruising.
* more freedom about where to place supercharger.
* operate supercharger at any speed independent from engine speed.
* can take advantage of regenerative braking.
Nobody claims that electric driven supercharger don't have disadvantages as well. But again that it is technically feasible and that it has advantages compared to a mechanical system, especially when it comes down to fuel saving measures, is obvious. And I also believe if Turbo system companies like BorgWarner are working on it, it can't be such a ridiculous concept after all.
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