Advanced Course in Hybrid Engineering

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Comments

  • tigercat21tigercat21 Member Posts: 28
    interesting article written for investors but fits here http://biz.yahoo.com/fo/050324/7c24d9694f94a129c9a6057aea23057a_1.html
  • toyolla2toyolla2 Member Posts: 158
    First I must mention that a post I was making here two weeks ago suddenly disappeared wiping out four to five hours of diligent work on the IMA system and wiping out an equal amount of enthusiasm. Too bad the edit box can't have a save feature. I am just going to have to discipline myself to make smaller posts.

    In the meantime tigercat21's post appeared linking to one of the best writeups of power electronics applied to automobile technology that I have read in a long time. Congratulations tigercat21for digging it out.

    I would like to add --
    A conventional engine costs about $70 per horsepower...
    For a parallel hybrid yes...but
    for a SHEV this cost could be lower since peak horsepower could be delivered at very high RPM, such an unconventional engine may bring the costs down to $30/Hp

    Power under the hybrid hood has to be converted and transformed again and again...
    Electric power-massaging equipment already is...


    This is an idea I put forward in earlier posts as electrodynamic conversion
    While those writers infer an upper limit of 500vDC, most industrial inverters are run on 660vDC because diode input bridges on 3-phase 460vac will produce this voltage across their main bus. But as I have pointed out before, there are 575vac inverters available off-shelf and, assuming they are not front ended with a 3-phase SCR half-bridge soft start, their IGBTs are probably working with an 800vDC bus. However for automotive use I believe designers will be looking at 1000vDC to be the limit. This limit would be set by the production of acceptably priced IGBTs when thinking in terms of power levels approaching 100kw. I remember some time back that there was a price premium on 1400/1600v 150amp replacement SCRs that I was ordering over the original 1200v devices, IGBTs will probably have similar price curves.
    One of the things that will have to disappear is this mindset with voltage - it causes problems. My experience has been that voltage should only be increased as power levels increase. For instance 10VA transformers on 220vac and 1/4Hp 3-phase 460v induction motors have a higher failure rate because the wire gauges used are fragile at these voltage/power levels. Similarly at the other end of the spectrum 240v 300 amp motors will need extra care and maintenance with wiring terminations than 500v 150amp machines. At those higher current loadings contactors whose connectors become loose have a tendency to burn up.(we found)

    About six years ago a 42volt consortium was set up because the limit of 3kw at 12volt was being felt in some vehicle designs as constraining future design improvements. Active suspension and replacement of hydraulic braking come to mind. Anyway a Prof at MIT in electronic engineering was spearheading an attempt to get vehicles equipped with 42v battery systems. The problem was that they thought in terms of moving all the existing systems into this next generation voltage. If active suspension was added in at the same time, this new technology would be moving in two dimensions at once. I would imagine some executives would not be thrilled at what effect this would have on long term reliability were that to happen.

    Of course a broadside move to 42volts was never necessary, and consequently never happened. The writers in tigercat21,s link mention Electric power-massaging equipment and that's what was necessary for the 42v crowd to do.

    An alternator wound for a stator voltage of 42 volts at idle rpm and a step down regulator to supply the 12v battery was all that was needed. If electronic valve actuation joins the mix then 42v will be required even when the alternator is stopped. In which case an upconverter from the 12v to 42volt bus would be needed. It could be enabled by turning the ignition key until such time as the alternator is able to supply the 42v load directly which would be as soon as the engine starts. Thus most of the components that require just 12volts could be left as is.
    I read the industry was also asking them for a combination starter -generator but I doubt that idea would be worth the expense and reduced reliability of a 42v battery that would then be needed IMO.
    Retaining the 12v battery and then trying to use a six-pack of high current starter motor transistors working off the 12 volt battery rail could be expensive particularly when they would have to survive 42v when the engine starts and the motor becomes a generator. But then there are 40amp surface mount devices that transform 3.3v to 0,8v for Pentium processors and they don't cost an arm or a leg so what do I know !

    The battery is there primarily for energy storage not to supply specific voltages that come in handy, that function is now for power conditioning circuits.
    Automotive suppliers seem to forget this important fact. Er.. where are the booster cables ?

    When it comes to stealth driving and regen I agree more storage should come with higher voltage. This is an area where not agreeing on an industry standard voltage was a big mistake by the car companies, it would certainly allay fears surrounding battery pack replacement costs if this component could have become a more common commodity item.
  • stevewastevewa Member Posts: 203
    If higher voltage is such a good idea, why did HSD go with a lower voltage battery than THS? Higher volts == more cells for a given battery technology, meaning more cells to monitor for reverse-charging. From a battery complexity and lifespan perspective, fewer, larger capacity cells are better.
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAMember Posts: 9,400
    I'd only add this caveat on higher or lower voltage being better or more efficient... given current technology. Who can say what breakthrough or discovery is waiting around the corner? I may not know what it is at this point, but I'm certain it's out thre waiting to be found. I recall a Windows Magazine cover froma few years back telling us that the 66 Mhz Pentium chip was it. We've hit the limit and can't possibly go any faster on chips. Same with the 28.8 modem, yada, yada...

    Like the song said, the future's so bright you gotta wear shades!
  • stevewastevewa Member Posts: 203
    That's why I said for any given battery technology. Obviously if they go from something like NiMH (1.25 v/cell) to LiPoly (3.6 v/cell) you can get more voltage from the same cell count. The complexity problem is the cell count, not the battery voltage or technology.

    Higher voltage is easier to work with because you can get the same power with less current, thus use lighter conductors.
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAMember Posts: 9,400
    Now that news story the other day about Toshiba coming up with a battery that recharges 60 times faster than current batteries is an interesting development. They're talking about the type of battieres used in laptop computers, but if you could achieve the same with batteries that would have enough power and duration to use in a hybrid, that might be something to see.

    PF Flyer
    Host
    News & Views, Wagons, & Hybrid Vehicles
  • electrictroyelectrictroy Member Posts: 564
    Yes, it means that Electric Cars would have unlimited range: Just recharge for 2 minutes while drinking your 7-11 coffee & then continue your cross-country drive.

    troy
  • toyolla2toyolla2 Member Posts: 158
    If higher voltage is such a good idea, why did HSD go with a lower voltage battery than THS?

    Hi Steve, you are perfectly right, IIRC :
    The Prius THS 2001-2003 had 38 cell packs for 274v
    and the Prius HSD 2004 has 28 cell packs for 201v
    As you point out - fewer but larger capacity cells are better.
    It provides for less possibility that an infant mortality could occur
    within one cell that could cause reverse charging and overheating
    and possible explosion.
    However I hate being annoying... But , IIRC, doesn't the HSD have an
    upconverter to raise the battery voltage to 500v so that MG1 can run at
    10k rpm max from the previously 6000 rpm max ?

    This was the paradigm shift in Toyota's thinking. They had needed to upgrade the THS. They had wanted more power at lower roadspeeds.To do this they obviously would need to run the ICE faster. This requires MG1 to run even faster and to support this would require a higher battery voltage perhaps 500v.
    They decided as you would have Steve, that this would impact the battery size, cost and reliability. So they looked around. Rewinding MG1 to run at 10k rpm on 274v was an option. But this gives a new problem for MG1's inverter which has to transfer the power from an MG1 which now must generate about 30% more current at its new max rpm. They were able to trade away both these problems by leaving MG1 as is and adopting the use of an upconverter.

    I don't think I have compromised my earlier statement that battery considerations should be for the storage function leaving power conditioners (an upconverter in this case) to handle special applications. tigercat21's link was also in the same vein.

    The 2004 Prius battery pack -from The Great Battery Debate forum
    The new Prismatic cells had an energy density only 15% more than the older cylindrical cells, though there were 28 cell packs rather than 38 previously. So the stealth range was reduced for the '04 Prius. The power density of these new cells increased from 800W/kg to 1300W/kg. This should allow 180 amps motor/regen current draw for a power of 36.4kw for as long as two minutes this is quite a performance change from the earlier cells.
    The 7.2v cell packs are rated 6.5amp/hr and weigh in at 1.04kg per pack.
    28 X 7.2 = 201v

    And if they were going to use an upconverter it would upconvert as easily from 201v as from 274v up to 500v.

    So in response to your post, although the HSD went with a lower voltage battery it did in fact use a higher operating voltage.

    Going back to that article in Electronic Engineering Times, and I quote :
    "The question on 42v is economics"
    No!! the question on 42v is electrocution.

    I wonder if it occurred to the 42volt guys that if you got booster cables wrong you could end up with 84v relative to the frame of the other car - you could risk being electrocuted while giving someone a jumpstart !
    I'm not sure I would like to make the National Enquirer posthumously.
    Then again if according to Dennis Miller the prospect of hydrogen fueled cars gives him a feeling of meeting two hundred potential Hindenburgs in a supermarket parking lot, cars with this 42v system might be off putting to most people. Though people are comfortable with car names like NEON, they would prefer not to find themselves glowing like one.
  • electrictroyelectrictroy Member Posts: 564
    84 volts doesn't sound deadly to me. It would be like touching an electric fence. Ouch. But not death.

    troy
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAMember Posts: 9,400
    I don't know for sure whether you'd get fried or just zapped, but having been zapped by a regular car battery before, I bet that a battery pack that can supply enough power to move a vehicle would give you a VERY healthy jolt to say the least!
  • electrictroyelectrictroy Member Posts: 564
    "a battery pack that can supply enough power to move a vehicle "

    .

    We're not discussing motive batteries. We're discussing 42 volt batteries.

    troy
  • tempusvntempusvn Member Posts: 119
    "We're not discussing motive batteries. We're discussing 42 volt batteries."

    Troy, if you've ever turned the starter with a car in gear, you'd know that even a 12V battery can move a vehicle quite easily. Probably not for long, but 600+ Amps is plenty of juice.

    The difference being pointed out was in the amperage rating of the batteries, not the voltage or how long they can maintain that discharge rate.

    So, in this case, we weren't discussing either motive batteries or 42V batteries. We were comparing laptop batteries with automotive batteries.
  • electrictroyelectrictroy Member Posts: 564
    "I wonder if it occurred to the 42volt guys that if you got booster cables wrong you could end up with 84v relative to the frame of the other car - you could risk being electrocuted while giving someone a jumpstart !"

    .
    Human skin = 100,000 ohms (worst-case)
    Voltage = 84 V
    Current = 0.84 milliamps

    According to http://hypertextbook.com/facts/2000/JackHsu.shtml it takes ~200 milliamps to affect your heart. ~10 milliamps to feel pain. So the 0.84 milliamps from a mis-connected jumper cables would be safe.

    84 volts is not deadly, or even painful.

    troy
  • cdptrapcdptrap Member Posts: 485
    The high voltage also brings up a new question regarding high EMF. Has anyone looked at or considered EMF in a hybrid vehicle?

    Some fairly good research showed EMF can have adverse effect on brain cells especially children's developing brains. It will be quite sad to reduce emission, reduce foreign oil dependencies, then end up frying our own brains.

    We are looking at buying a highlanger hybrid because we have children and need a roomier car that saves gas and is somewhat green. EMF is the next isse we must resolve.

    Thanks in advance for any interest in this area and your input.
  • gagricegagrice Pahrump, NevadaMember Posts: 31,450
    Good question. Here is one complaint concerning EMF. I have no idea of the accuracy. Read and research for yourself.

    The driver is receiving up to 135 milligauss (mG) at the hip, and up to 100 mG in the upper torso and head area. For comparison, my VW van measures between 1 and 2 mG. The technicians who measured the EMF advised me not to drive my Honda until this problem is fixed.

    To put this into perspective, the Liburdy and Colleagues Study in 1993 found that just 12 mG stimulates the growth of estrogen-sensitive breast cancer cells. Epidemiological studies have found an increased risk of breast cancer among both men and women exposed to high electromagnetic fields at work. A study by the Natinoal Institute of Environmental Health Sciences (NIEHS) called "assessment of health effects from exposure to power line frequency electric and magnetic fields" confirms the dangers of high EMF.

    Incidentally, the Prius I measured was fine in the front seats, but the left rear seat had similar readings to the Insight.


    http://consumeraffairs.com/automotive/honda_insight.html
  • stevewastevewa Member Posts: 203
    Remember, you can weld with a 12v car battery. The voltage may be shocking (a static electricity shock is multiple thousands of volts) but it's the current that kills.

    I agree with the analysis that toyolla2 makes about the voltage in HSD versus THS. The downside of using a lower voltage is the need for heavier cables, as the amperage must go up to provide the same power output. But lowering battery voltage had distinct advantages while increasing voltage to the motors had its own advantages. Those clever EEs at Toyota found a way to have both.

    As to EMF exposure, it's one of those great unknowns right now. Certainly shielding from the steel in the unibody should help with that. Perhaps the unconventional construction of the Insight didn't put enough steel between the HV cables and the driver/passenger?
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAMember Posts: 9,400
    But every time *I* see a study cited, questions always come to mind about the study and what it really means. First phrase that I'd like to know more about is "exposed to". For how long? Is the exposure in the study comparable to the exposure in the vehicle? Or is this going to be another one like cell phones causing brain cancer?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    So people are always calling me up asking me what to buy.

    I don't know too much about hybrids.

    Should they buy the Prius or the Honda, and tell me why you think so please!
  • stevewastevewa Member Posts: 203
    Most of these studies are non-conclusive because they study populations and try to infer relationships that may or may not be there. In order to _really_ know if x causes y, you'd have to take two identical groups of people that live identical lives, and have one exposed to x and the other exposed to a placebo that looks like x then you could measure the difference.

    Beware when anyone tells you "risk is 5 times as high" because that might be a risk of .0001 percent jumping to .0005 percent.
  • electrictroyelectrictroy Member Posts: 564
    I'm an electrical engineer. Guess I'm going to die young.

    ;-)

    Prius or Honda. I like the Civic Hybrid better than the prius. The manual shift (or cvt) is more fun to drive.

    troy
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well that's a good advantage. I found the Prius interesting but no fun to drive. Never have driven the Honda. Anything else that comes to mind to put in the plus column for the Honda?
  • stevewastevewa Member Posts: 203
    I'm an amateur radio operator. I get magnetic and electrical fields from my hobby!

    I find the Prius pleasant to drive (we have a 2002 so it's the older design). The Escape hybrid is more fun, but it doesn't get the same fuel economy (still good for an SUV though).
  • gagricegagrice Pahrump, NevadaMember Posts: 31,450
    I'm an amateur radio operator.

    In my 43 years in the telephone business I have worked with many radio and Microwave technicians. Several have died in their early 50s of brain cancer. Especially those exposed to tropospheric scatter radio. The newer technologies seem safer. I would be careful. Why did GM pull the plug on the EV-1?
  • electrictroyelectrictroy Member Posts: 564
    Another plus for the honda is that it can still work without the Driving Battery (the one in the back). Even at 300,000 miles when the Honda is old & grey & the battery is barely-working, the Honda can still be driven as a pure-gasoline car.

    troy
  • energyeconenergyecon Member Posts: 16
    Can an engineering type fill us less technical folks in on the maximum amount of braking HP can be used to regenerate? (by vehicle model obviously). I know that batteries are limited in their maximum recharge rate. I believe it is 15% for lead acid gel cells. How about the NiMH batteries used in Prius or Highlander? Hondas? Escape?

    In addition to HP, it would be interesting to get the answer in terms of the rate of decelleration or the maximum grade that can be held by regenerative braking alone.

    I am I correct in assuming that the model with the greatest amp-hours have the greatest regenerative storage rate? How do the different battery voltages affect this (if they do)?

    Curious marvin
  • toyolla2toyolla2 Member Posts: 158
    Well, the lowest voltage that caused electrocution, to my knowledge, was 56Vac to a Tyne-side ship welder. He was working in a confined space and his ear touched something live, or so they said. My personal experience is that 43v between knee and hand will make you jump. 67volts with damp fingers gives you a painful tweak, so 84v with good contact I don't wish to contemplate. AC voltages will throw you off as the muscle receptors are polarity sensitive. DC is more dangerous because it will freeze the muscle and hold you on. Some people have waxy skin and measure 10 times normal i.e. 1 megohm. Of course if a whisker of wire pricks the skin then Bobs your uncle. (or in this case your late uncle)

    How much horsepower does regeneration yield ? The easy answer is about the same horsepower as when motoring since inverters typically can be set to give the same current limit motoring or regenning. The problem is that usually you want to decelerate in a hurry much faster than you would want to accelerate. The cost of the inverter depends on the maximum current. So is it worth investing in larger semiconductors for the occasional 3 second emergency stop?-probably not. This is when absorbing the spillover power can be more efficaciously accomplished by mechanical brakes which can be arranged to become progressively fierce depending on pedal pressure.
    But supposing you wanted to spring for the larger electronic braking option. Then you have the option of over-amping the battery which for 3 seconds you could probably get away with. However descending a long steep hill under heavy regeneration would not be a good idea for the battery IMO.
    The Prius HV battery can absorb about 100amps from motor generator 1. It is a 6.5 amp-hour battery so it would be fully charged in about four minutes.

    But for the ultimate in energy exchange - Ultracapacitors- are the thing.
    In 1998 SRI International licensed its ultracapacitor technology to SANYO Electronic Components Co.
    They have a specific energy of 12 watt-hours per kg -- how far can you go.
    And a specific power of 1000 watts per kg -- how fast can you go.(or stop)

    If a vehicle weighing 1000kg is braked from 40 mph (20m/Sec) to rest.......
    Then using the 1/2Mvsquared formula yields 200kw-seconds of energy

    The specific energy of 12 watt-hours or 43.2kw-seconds means 5kg of this component could do the job. Yes but...if you wanted to brake in 3 seconds the capacitor would have to absorb at a rate of 67kw. This means you would need 67kg of it. So it would appear that you are power-limited with ultra-caps.

    Now let's say you performed controlled braking in 9 seconds you could now use just 22kgs which looks more reasonable and that device would only store 4 times more than you needed it to. Hopefully ultra-caps have improved since 1998 ?

    What interested me about this story is that Sanyo later partnered with Honda just as Panasonic (Matsushita) does with Toyota.

    I would be interested to know whether regeneration has made noticeable wear reduction in the mechanical brakes to hybrid owners. Otherwise I believe regen is somewhat overrated IMO, seems like a good idea to newbies but in practice only 5-10% improvement and then only in stop/go driving.

    It's like photovoltaics, when you get into it, people in the know say it is a good idea for satellites where no expense spared, but here on earth using consumer quality materials exposure to the sun usually means rapid degradation before payback is reached.

    Regen has been used with battery EVs using lead-acid. When battery approaches full discharge the driver is supposed to do a full regen stop at the next stoplight (rather than coasting). This increases the ionic mobility within the cells. When the stoplight changes the vehicle will take off as if it were freshly charged for the remaining miles.
  • electrictroyelectrictroy Member Posts: 564
    "AC voltages will throw you off as the muscle receptors are polarity sensitive. DC is more dangerous because it will freeze the muscle and hold you on."

    .

    This is a myth. When the AC reverses polarity, it releases one muscle, but then contracts a different one, and you're still stuck.

    Also, the limiting factory in regen is not the inverter. It's the battery. Charge it too fast, and you damage the battery's internal chemistry.

    troy
  • stevewastevewa Member Posts: 203
    Ford claims front brake pad wear is less by one-third compared to standard Escape. However since regen doesn't work on the rear wheels they wear faster than the fronts.
  • electrictroyelectrictroy Member Posts: 564
    Are you sure? Seems to me that the rear brakes would not be engaged during 100% regen braking, thereby reducing their wear too.

    troy
  • toyolla2toyolla2 Member Posts: 158
    Yes I am with you on this one, Electrictroy. When mechanical braking starts to take over when does the driver know ? Is there some sort of feedback through the hydraulic system back to the brake pedal that gives some indication ?

    Regen for me is not so much energy conservation as money conservation.
    For instance, a front brake pad replacement will run you $124.95 in Toyota's value pricing as quoted from their 2005 winter Gazette publication. It doesn't make clear whether that is the price for doing both front wheels or just the one. But it does go on to say that each brake repair is different so there may be additional costs. No kidding ! Have you noticed when the service manager invites you into the garage to inspect your car on the hoist that.....well, it's never good news is it ?

    It's what they call "Fear Maintenance" a play that starts Act I scene 1 like this : -

    There's always something that service has an inkling "is about to let go" isn't there? Or is it just me, am I the only one this is happening to ? Then the guy cajoles me into being a sport and OK-ing the extra work (which will end up costing twice the original quote). And hey, who doesn't appreciate a spot of clairvoyance mixed in with the physics of their automobile repairs. But no more. Today I have a new philosophy on safety (although I still have reverence when it comes to handling 84vDC -Electrictroy please note) and this is courtesy of Seinfeld. I will inform them that when it comes to safety I have now reached that age when I will back out from my laneway onto the highway..... without looking.
    (It's also happens to be my way of saying to younger drivers in the vicinity "I've survived this long now let's see if you can".)
    I expect such an outburst to fastforward the service guy to Act III scene V which is me back in the waiting room. You have to treat service with tact. You never know with these guys, clairvoyance one minute could become psycho-kinesis the next if you get my drift.

    Now here is a fight no one seems to want to get into. And, surprise, surprise it has something to do with hybrid engineering. Let's take an L4 Camry we all know that it gets better mileage than a V6 Camry. It's also a given that if the V6 Camry engine was turning over at 2500 rpm at 60 mph then at this speed the L4 engine would be turning over at around 3200 rpm. Now supposing that there was such a thing as an L2 engine. We could probably agree that it would need to turn over at 4500rpm. Logically it should yield better mileage than a L4 but there are those who see a faster turning motor as less efficient. So my question is Why does the efficiency versus cylinders peak out with the L4 ?
    If an L3 or L2 cannot compete I would like to see the quantitive analysis that is supporting my questioning statement - if there is any.
  • momotarosanmomotarosan Member Posts: 2
    two friction regen motors at each rear wheel...sensors on gas and brake pedal to tell motor to regenerate...battery pack in the trunk...speed sensor to tell electric motor to drive the car when speed is low and charge is sufficient...

    wouldn't this save us from importing so much oil?
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAMember Posts: 9,400
    Even just starting with the weight of the batteries and motors, you're going to kill off some mileage right off the top. Add in the cost to retrofit, which HAS to cost more than just building the car as a hybrid in the first place, and it doesn't seem like it would make any sense financially.
    And we haven't even gotten to talking about WHERE all this retrofitting is going to fit on the car...
  • mistermemisterme Member Posts: 407
    "Has anyone looked at or considered EMF in a hybrid vehicle? "

    If I were concerned about EMF and any human exposure consequences, I'd be much more worried about the common CRT computer monitor, or watching a CRT color TV too closely.
    (As kids sometimes do)
    In both cases there are 3 Electron guns emitting their radiation right at the face.

    I don't think EMF causes any problems in hybrid cars.
  • stevewastevewa Member Posts: 203
    My info comes from the Escape Hybrid service manual.
  • toyolla2toyolla2 Member Posts: 158
    BOB HUNTER passed away one week ago. He was a co-founder of GREENPEACE.
    On Sunday afternoon MAY 15th 2005 there is a public memorial being held at U of T's Hart House.

    I have written most of what I have to say on Serial Hybrid Electric Vehicle drivetrains (SHEVs) in this forum already but it appears that people aren't getting the message or maybe don't have the education to perceive what is going on here. Nothing wrong with that. To understand you have to be prepared to put yourself into a certain mindset and take things as they are and draw the corrollary that just as if it sounds too good to be true it probably is then if it feels like BS it probably is too. People use language for social grooming as much as for the exchange of ideas hopefully the following will be seen as the latter.

    Years ago I used to smoke cigarettes. It relieved stress. A cigarette is a cigarette. Had someone told me, at the time, that more accurately a cigarette was not a just cigarette but a delivery device for the mood altering drug nicotine then my response would probably be at the earliest opportunity not to be in that person's space. I was not ready for that sort of dissection.

    Talking and writing about SHEVs is the same thing. People are used to the idea of a reciprocating engine to convert chemical energy to mechanical energy and then using that rather arcane method of mechanical clutches and gearboxes to connect this energy to the wheels. Why stop now when it's been working so well for so long ?

    Hm... I see a whole industry built on that arcane method going wrong. Tune in to a call-in radio show on car problems. Let's see caller - you ask is it OK to drive around with that little red lite on, 'cos I can't feel any difference in my car ? Well caller, if you want a minor transmission problem to develop into a major transmission problem it's quite OK. Next caller please !

    The arcane method, let's call it mechanical power conditioning as opposed to the electrical power conditioning found in the SHEV, has another disadvantage besides being a breeding ground for expensive and tricky repairs. It's not that good at what it does. When working as designed pure mechanical power conditioning still offers poor utilisation of the available engine power. Does a mid size sedan really need 200Hp to do 60 in eight seconds ? Do the math it's much less than half that amount. Look, GM's EV-1 could this and while carrying 840lbs of lead with only 114Hp. Had I been with GM around then I would have suggested experimenting with a series/parallel arrangement of the two induction motors to reduce the base speed from 40 to 20mph thus clipping another 1.5 seconds off this time.Using the same electronics-different software. This is the sort of advantage that electrical power conditioning can give you.

    So to continue, if hybrid vehicles are going to progress and become lighter, simpler and hopefully cheaper then you need to adopt a different mindset to enable you to get there. The mindset you need is that the reciprocating engine should only be doing the first part of the job. The chemical to mechanical power conversion. If that is its only mandate to produce mechanical power then multicylinder engines are unnecessary, just run max RPM whenever you need max POWER from the one or two cylinders that you have. Of course this presents formidable difficulties for mechanical power conditioning systems. But for an electrical power conditioning system this is a piece of cake. The electrical system will have three parts.

    1. A generator which will be housed in the engine block similar to Honda's IMA taking advantage of liquid cooling and direct drive. It could even be somewhat similar in size since the IMA is built (erroneously I think) to provide max power at sub 1000rpm, the generator I propose would be sized for max power above 10K rpm and for just 30 seconds at that level. For those wishing to do 100mph from rest ! The 10k rpm and 30 second rating together with liquid cooling makes this a very small frame size machine compared to its industrial brother at 1800rpm and 24/7 operational expectancy. Three wires carrying 3-phase power will go to the next device.

    2. An inverter. This compact inverter will share liquid cooling with the engine. The great experiment with the american public known as the Prius experience has proven this to be a good idea for semiconductor reliability. Industrial inverters are designed to trip out +/-15% outside nominal input AC voltage. This inverter will not. It will be enabled to be variable voltage input bus compliant over a 100 to 800vac range. Three wires carrying 3-phase power will go to the next device.

    3. A 3-phase liquid cooled induction motor. Everything needs liquid cooling, it's hostile in there, that's a no-brainer.This is the one part of the system which I expect to take extreme abuse. This will not have the luxury of running at full power at high speed like the generator. It will often be called upon for nominal torque at speeds below 1000rpm and depending on design of the aforementioned inverter may be called on for short time rating of 300% over torque. It is easy overbuild this component but with a weight and cost penalty. Worst case can be avoided by an electronic limp mode on excessive temperature rise. Eventually some will fry. But it's an induction motor if you can get it out the car the local electrical shop can rewind these in a couple of days with a better turnaround than some of the HCH and Prius parts have been having. And when disassembling your fingers will appreciate the non-magnetic rotor too.
    The end bell of each motor will house the 10:1 planetary reducer. And in case you want to mention it, I'm not sure why GM went to a standard transaxle single motor design either.

    I haven't mentioned the inclusion of an HV battery as I happen to see stealth as an option. But stacks of people seem to want it at the expense of 60/40 notchback rear seating.
    So without the HV battery, how is the car started ? Well if they can get 500watts audio off of 12v then you shouldn't need to be persuaded that it should be doable to start this car using an upconverter to lift 50v from the 12v battery onto the main bus where a small inverter will treat the SHEV generator as a starter motor. The bit I particularly liked about this is when I realized that the body diodes on this circuit can become the main 3-phase bridge rectifier when the engine is fired up. No changeover relay here just inhibit gate drive to the starter inverter transistors and you're good to go.

    Electrical power conditioning offers a reverse gear without needing mechanics
    as the Prius, the Escape and RXH400 also do.
    The silverado crowd may also be interested seeing how 5 kw got their attention. Imagine what might be done with an auxiliary 3-phase plug from the SHEV generator to an
  • toyolla2toyolla2 Member Posts: 158
    external fixed frequency inverter for providing 30kw to a building site.

    Hopefully we can become more environmentally aware and one day have vehicles that do have great performance without requiring gas guzzling engines with class leading horsepower.
    And now I have to go.
    As Bob would say at the end of his 'Hunters Gatherings' TV program

    " Until the next time FIGHT THE POWER "

    T2
  • gagricegagrice Pahrump, NevadaMember Posts: 31,450
    You are way ahead of me on the design of hybrids. I was a big fan of the EV-1 vehicle. I think that millions of Americans need a car for short trips (1-3 miles) in the Suburbs. The current hybrids with poor initial mileage are not a great solution. Golf carts are not real practical either. I think the hybrid with enough battery to carry the car for a 10 mile round trip would be a good solution. One of the downsides of the Prius for me was the 30 MPG on the first few miles. I can get that with a small gas or diesel car and not add the complexity or the additional cost. I really think we are at an impasse on the hybrid technology until a better, lighter means of storing energy is perfected. Lithium ION batteries may be OK but not environment friendly. Capacitors may be a solution, I really know little about them.

    I do read your posts, not always understanding, all I am reading. Have a good week.
  • bulhambulham Member Posts: 1
    Hybrid vehicles have been around longer than you may think. In fact a fellow by the name H. Piper applied a patent for a vehicular powertrain in which an electric motor would augment a gasoline engine back in november 1905. This discussion is more than 100 years old. The dominant vehicle technology today, the internal combustion engine vehicle (ICEV), is actually a hybrid car of an ICEV and an electric vehicle (EV) in the late 19th century. All the advantages of an EV in that days were implemented in the ICEV (tires, battery..ect.). Hybridization is a process that is around us all the time and engineers will keep developing better cars with improved functionalities.
    Does anyone know relevant theories that can explain this phenomenon hybridization? [evolutionary theory]
  • falcononefalconone Member Posts: 1,726
    Perfect solution would be a segway for short trips. I owned one two summers ago just to see if I would like it. Great fun, but little pricey. Got it on ebay. www.segway.com
  • falcononefalconone Member Posts: 1,726
    Any car that is driven the first few miles has POOR mileage. Not just hybrids. My partner's C230 coupe with a 4 cyl engine gets 17mpg on a 4 mile r/t to the market. A golf cart would be good for short juants to the market. We used to do that when we lived in Rehoboth.
  • gagricegagrice Pahrump, NevadaMember Posts: 31,450
    I agree that all cars suffer from poor mileage the first few miles. My complaint with the hybrid is if you bought it for the 50+ MPG and get 30 MPG you are going to be more unhappy than if you buy a car that gets 25 MPG and drops to 20 MPG on the short trips. We rarely drive our old Mazda further than 3 miles. And it usually gets 19 MPG on fillup about every 2 months. The HSD hybrids seem to be optimized for Stop & Go commuter travel from 10 - 40 miles per trip. If that does not fit your needs they may not be the vehicle for you. Maybe the IMA of Honda would be more what you need. I have not heard as many complaints about mileage with the Civic Hybrid mileage. They are getting closer to EPA than the Prius. The Prius seems to be averaging 48 MPG vs 55 MPG EPA, the Civic is 46 MPG vs 47 MPG EPA estimate.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I've been monitoring both longterm road tests and data from owners and the Prius averages closer to 41-44 mpg in the real world. Don't have enough data on the Honda but what I do have suggests lower than 46 mpg.

    I think the reason is that most people are using them on the highway more than in city driving, for which they seem better suited (or low speed urban driving I mean).
  • gagricegagrice Pahrump, NevadaMember Posts: 31,450
    I was giving them the benefit of the doubt. I used the mileage compiled on brand X website. I do think that may be a bit skewed as it is geared toward the hypermiler group of drivers.
  • falcononefalconone Member Posts: 1,726
    I believe CR got lows 40's with the Prius in their tests and the Honda Civic was a little lower, but not much.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Yeah, Road & Track and Edmunds got about the same numbers, so the data seems pretty agreeable.
  • larsblarsb Member Posts: 8,204
    If anyone thinks the Honda Civic Hybrid is good for consistently "lower than low 40's" then they are completely incorrect............That would only happen if you drove with the accelerator on the floor about 50% of the time and completely ignored the tools Honda provides which allows the driver to understand how and when they can achieve efficient MPG performance.

    Even with my WORST tank, when I knew NOTHING about how to drive my HCH, I still got 38.43 MPG.

    Anyone who consistently gets those numbers is not learning and deserves to get 15 MPG below the EPA rating....
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well it's very possible (in fact likely) that many owners don't know how to properly use their hybrids to maximum efficiency. But that's what "real world" means....how both the car AND the driver are apt to behave in most conditions.
  • larsblarsb Member Posts: 8,204
    I'd say anyone who is unable/unwilling to look at a "real time MPG gauge" and see that when they push the gas

    THis much

    it moves up to 80 MPG and when they push the gas

    THIS MUCH

    it drops to 40 mpg

    is not one of the people who will care about achieving 47 miles per gallon...and in turn, they have NO REASON to complain....:D

    My point being that "It's not Rocket Science" to figure out how to drive a hybrid car/Suv for maximum MPG - all it takes is a little bit of paying attention to your gauges.....
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well it's a question of how intuitive all of this is....if the product requires a lot of study or constant manipulation to achieve efficiency, it simply isn't going to perform to factory specs because of the tendency of humans to ignore complex directions.

    They want to get to work, they don't generally want to be watching the MPG meter.

    I could get 23 mpg out of my car but I'm certainly not going to take the time and effort to do that....maybe 1 of 10 people will....but that 1 of 10 won't be posting the 'real world" numbers.

    This discussion reminds me of the Corvair flipping over...it would never flip if you filled the tires to the precise inflation pressures....but most people ignored that. And the first turbo cars in the early 80s, required certain driving habits to prolong turbo life----forget it, people ignored that too for the most part. They simply were not going to idle the car for a minute before shutting it down.

    I think hybrids will have to defeat the driver's brain if you want to see 60 mpg out of one. In other words, you pre-set the mileage you want to get and then the computer will prevent you from doing certain things....kinda like traction control does now...
  • gagricegagrice Pahrump, NevadaMember Posts: 31,450
    they have NO REASON to complain

    I don't disagree with you, as I find myself playing the numbers game with the mileage on the Passat. I noticed that the EPA on their estimates are now including Real World mileage for the hybrids and maybe some other vehicles. They show the Real World mileage for the Civic Hybrid at 40.9 MPG combined with a variation from 39 to 43 MPG. They gave the Prius II a 49.7 MPG average user mileage. I wonder if that will show up on the Window sticker? This will go a long ways to quiet the people that buy a Prius and expect a combined 55 MPG and only get 45 MPG.
This discussion has been closed.