Hybrids

The problem as I see it is that hybrids flunk the basic keep it simple principle. They have far more components than their conventional counterparts and weigh more as well. More complexity and more weight. Not good general starting point to achieve better efficiency.

Many of the hybrid vehicles are also using other tricks to get some of the fuel economy, which tricks do not require the hybrid powertrain. Smaller engines as you mentioned are one trick. Narrow, high pressure tires are another trick. Cylinder deactivation is another (as used on the V-6 hybrid Accord).

Marketing and hype are clouding many of the facts.

John

The main advantage a hybrid has is it's ability to recapture some of the energy which would otherwise be lost to heat by conventional braking. On the open road this is a non-issue.

The second potential advantage of a hybrid is that the gasoline powered engine can be shut down when the car is stopped and the stored energy in the batteries can be used to keep the A/C, radio and other systems alive.

The biggest disadvantage a hybrid has is that it is heavier than the same vehicle without the added batteries and electics. The work done in moving and object from one point to another is a function of the distance and the weights (ok, mass). All other things being equal, a heavier vehicle gets lower fuel economy than a lighter one.

Oddly enough, GM may have the idea more "right" in their limited production pickup truck hybrid system where the electrics are small and light and really only have anough capacity to enable the shut down of the gasoline engine at a dead stop.

John

Smaller engines are not a trick but a consequence of hybridization. One of the driving philosophies of hybridization is that it is ludicrous to use a

240 hp engine to move a 5 passenger car around town. Hybrid powertrains make it practical to downsize the engine, since the limiting factor then is the power required for freeway hill climbing - the electrics determine the acceleration performance. Again, I'll grant the current crop of hybrids don't go very far in fulfilling that promise but even the older Prius (like mine) is far more responsive in town than the 75 hp engine would suggest.

No modern car "keeps it simple" but you might consider the tradeoff. The Prius powertrain is complex in concept but not in practice. Actually, any automatic transmission is vastly more complex than the hybrid transaxle. Honda autoboxes are a good example. They have a controller; the hybrid system has a controller. The hybrid system has an inverter; the Honda does not. The hybrid transaxle has a fixed planetary power split device and two motor/generators; the Honda box has an automatic transaxle with lockup torque converter, multiple gear sets, pumps, valves, solenoids, and clutches. The Toyota hybrid system has a main battery, a 12V aux battery and a voltage converter; the Honda has a starter, alternator, regulator, and belts. If the Toyota hybrid has cruise control there are switches; if the Honda has cruise control there is a cruise control module, switches and vacuum motor.

Reliability has seemed to favor the Toyota hybrid system over conventional systems in several areas. There are two known cases of hybrid transaxle failure and unconfirmed rumors of as many as 3 more among the 11000+ members in the Yahoo Prius group over the past 4 years; compare that to the number of automatic transmission problems that show up here. The same Yahoo Prius group has frequent complaints about failure of the undersized 12 volt aux battery, comparable to the number of complaints here about alternator problems (but a whole lot easier to fix). There are a modest number of starter questions here (like "why did my aftermarket rebuilt starter fail the next week" and "how do I get the darned thing out") while the Toyota system has no starter.

Mike

"Michael Pardee" wrote in news: snipped-for-privacy@sedona.net:

Which only are 'used' when power is lost. They are "stand-by" batteries used in UPS (uninterruptable power supplies) systems.

Batteries used for hybrid autos are -always- in use.

Yes, I agree that it's no surprise at all for those of us that truly understand Hybrid vehicles. However, the vast majority of people that buy or plan to buy Hybrid vehicles do NOT understand Hybrid vehicles. I've see at least a dozen posts in this and other car related newsgroups from Hybrid owners that were shocked when their miles per gallon were much less than they expected it to be. In almost all of these cases, those people were making use of their Hybrid cars to do lots of freeway and interstate driving. It's obvious that the salesmen that sold them the Hybrid cars did NOT tell them about these factors. My memory is not perfect but I seem to recall that the car mentioned in the above post was a Toyota Prius.

Hello, I have a question for you. Do you know whether or not Toyota and Honda informed people in the brochures related to their Hybrid vehicles about the true nature of Hybrid vehicles? For example, do they (in their brochures) warn people that if they plan to use their Hybrid vehicles mainly on interstates and freeways that the miles per gallon will not be very good?

I have seen several posts from Hybrid owners indicating that they were shocked to learn that they only get great gas mileage (aka miles per gallon) when they do lots of city driving. The makers of Hybrid vehicles should inform people about the nature of Hybrid vehicles before they buy them. I hope that they do it but don't really know since I have not read the brochures. Jason

Rechargeable batteries are an odd creature. I have a little Milwaukee power screwdriver (like the ol' Black & Decker "PowerDriver", but an actual pro-duty tool) that came with two 2.4V NiCads, which have long been notorious for short life, voltage fall-off and "memory effect". The first battery I had to replace after *EIGHT YEARS* of regular use, when it wouldn't take a charge anymore. The second finally gave out three years later... or at least came close to giving out, before I replaced it anyway. 15 years after I bought it, that driver is the best $200 I ever spent.

Meanwhile, I've owned two IBM ThinkPad laptops, both using more modern, supposedly more robust Lithium Ion battery packs. Both started showing a marked decline in charge life after less than a year, to the point that they wouldn't hold a charge at all after less than two years. I've seen similar with several other LiIon laptop batteries as well. At $200-$300 or more each, they're a pricy investment.

What do you consider "not very good'?

Matt Ion wrote in news:Oe8ke.1449067$8l.39712@pd7tw1no:

NiCds are "use it or lose it" type of batteries.If you use infrequently,they do not hold up as well as if you use and recharge them often. Also,using a "fast" smart charger (1 hour or less charge time)goves a longer battery life.

Here in Tucson, we've had good mileage with our Civic Hybrid. In cool-season city driving, we really do get 45-48 miles per gallon (those are our calculations--the car's computer display inflates mileage by about 3 mpg), with the CVT. In summer, we probably lose about 3 miles per gallon, thanks to the A/C, and whether we have to force the engine to run to keep the cool air blowing at traffic lights (when it's 110 degrees outside).

Freeway driving gives around 36-42--speed limit is 75; real-world practice is closer to 80. Mileage is somewhat better on two-lane roads where the limit is 65. I've noticed a bigger hit on this car from using A/C than on other cars we've had. I'm not complaining; the vast majority of our driving is city driving, and that is this car's strength. It's very enjoyable to get close to 600 miles on a tank of gas.

David

ACtually, that depends very much on the model of the cell, and its condition. There are ways to condition cells, but i don't reccomend them to those unskilled, but it basically involves zapping the cells, to break down the crystal biuldup 9conductive crystals form, which produce a 'shotened' battery, hence the memory effect.

Condition them right, charge them, look after them, and they'll always do you good, right to the end of their design life, and often beyond.