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Design Article

# Is there a future for hybrid vehicles? Part 1

## 8/31/2010 2:40 PM EDT

Hybrid powertrain optimization
One of the neatest HEV powertrains I know uses a very simple construction of a planetary gear system being driven by two power sources: First, the ICE, and, second, an electric motor. Power is diverted off the ICE to drive a generator, which in combination with a large battery, powers the electric motor (see figure below). The diversion of power to the generator is regulated by electronics that determine how much the generator provides charge and, as a result, how much of the ICE torque is directly sent to the wheels. The amount of power the generator demands from the ICE is related to the amount of power it generates.

A popular style hybrid electric vehicle powertrain

By regulating the split between mechanical and electrical motive sources, the ICE is allowed to run at its optimum speed/torque for extended periods of time. This improves the efficiency of the ICE dramatically. There is a sweet spot in the engine rpm/torque curves that provides the best efficiency (see figure below). Hybrid technology allows the engine to stay in that sweet spot longer, thus providing much better fuel economy.

ICE efficiency curves

Secondly, the gasoline engine can now be much smaller because the torque needed to accelerate is shared between the electric motor (and its accompanying battery storage) and the ICE.

Doing the math on one typical hybrid powertrain (from a popular brand’s website), we get:
•   ICE power                 = 98 hp
•   Electric motor power  = 80 hp
•   Battery capability        = 36 hp
•   Total available power  = 134 hp

Note, that the total available power is just the ICE and what the battery can deliver. To me this seems a bit simplistic because 134 hp is the absolute most power that can potentially be in the system at any one time. Between the 201.6V battery and the wheels is first a 650V DC-DC converter and then a three phase inverter and then the motor-transmission.  To assume that the heat generated by these elements is negligible is optimistic. Unless these smart guys have invented the next best thing to perpetual motion, lossless energy conversion (from battery to motion), they are being a bit optimistic.

Am I picking nits? Yes, I guess so. These hybrid engineers have done a lot to minimize the losses between the battery and the wheels. For instance, the DC–DC converter and 650V inverter-motor waste much less energy than a 200V inverter-motor would. Using a battery and electric motor to boost the powertrain output during high loads and taking advantage of times when the engine load is not so high to replace that energy drained from the battery improves the efficiency of the ICE.  Improved efficiency also means lower exhaust gas emissions for the same output power. And that’s a good thing.

(Part 2 of this feature discusses regenerative braking and a future beyond hybrids.)

David Swanson is principal engineer at STMicroelectronics.

eewiz

9/1/2010 4:46 AM EDT

Interesting story about the perpetual motion machine. Reminds me of a discussion Once I had with a friend about putting Piezo electric transducers into the tyres of automobiles to generate "free" energy :).
One point to be noted is that for plug-in hybrids, the batteries can be directly charged from a power outlet. So the energy consumed may be cleaner based on the source of electricity. In any case I feel Fuel cell/Fully electric vehicles will overtake HEVs in future.

http://www.lulu.com/spotlight/poconoarmchairreview

9/1/2010 6:34 AM EDT

Or, we could adapt motion and heat energy harvesting devices to capture energy from the motion and heat of a walking person. We could use the energy so gathered to propel the person along. Oh, wait. The person is already moving, by himself. So, maybe we could use the electricity to power an iPod, or maybe a cool LED light.

MrDave

9/1/2010 10:38 AM EDT

Check out
http://www.treehugger.com/files/2008/06/bra-power-breast-charge-ipod.php

;-)

Mi302

9/1/2010 8:46 AM EDT

Unless the energy density problem is solved, no. Hybrid cars fit only certain peoples needs, never mind tastes and I doubt the public wants to ride the volume/cost curve to where they are price competitive with say, a toyota corolla.

My dad owns a Prius, I though it had a cool dashboard. However on the highway the wake of a passing tractor trailer truck made the car lurch more than I was used to. He said it was normal, I rolled my eyes.

RickMatz

9/1/2010 8:50 AM EDT

There's a lot of room for wringing out efficiencies in internal combustion engines and improved transmissions.

Bob Lacovara

9/1/2010 10:08 AM EDT

I'm one of those guys who drives a suburban assault vehicle. I like it; I hope never, ever to hit one of those teensy weensy toy cars with my FJ Cruiser. It's not my ego that bought the FJ... it was the desire to wrap my family some old-fashioned safety (steel) and some new-fashioned safety (airbags everywhere). Also, I have been long skeptical of the overall economy and "green-ness" of hybrid vehicles, mostly because I'm a battered and cynical old engineer, and I know that not only nothing is free, but almost everything has hidden costs. In hybrid vehicles, the hidden costs, as pointed out, are horsepower (say, to tow a trailer), size (to reduce drag), and cost. Heck, my Corolla gets about 30 mpg on the highway: what would I have to pay for a smaller hybrid? All-electric cars, we note, just move the point of fuel combustion to a centralized source, the power plant, which is a bad thing unless your power plant happens to be fired by uranium. And battery manufacture is reportedly quite dirty. Most of it's in China, though, so that's ok: the US tree-huggers don't see those plants. Out of sight, out of mind. I will continue to burn fuel in my SUV as much as possible, to hasten the day that there's no gasoline available: at that point, all of the wacko (and merely wishful) energy schemes can be put into place, and then, I suppose, a utopia will arise.

agk

9/1/2010 10:20 AM EDT

All over the world auto enthus are interestingly watching the developments taking place in the Hybrids. i am also one among. It is interesting to note that ICE has a optimum point at whcih this is highly efficient and ICE works around that point in the hybrids and charges the battery. This concept is great. My thinking goes far beyond this. Hybrids uses two level energy convertion gss to electricity and electricity to motion energy. Even though engineers had optimized the system for fuel efficiency and higher power when it comes to maintanance part this is highly expensive, The initial investment also higher and i do not see a big attactive crowd to buy these. In India 2 years before a leading company launched the hybrid and after 6 months time the price was brought down by 33 percent. This is quoted here as a reference for the demand of Hybrids. Later at a point of time when the pollution levels are imposed by the governments to a lowest level hybrids will win the market place

BicycleBill

9/1/2010 10:35 AM EDT

What? There is no free lunch? There is no something for (almost) nothing? The laws of physics can't be bent to our desires and dreams? I am shocked and saddened....

Bob Lacovara

9/1/2010 10:41 AM EDT

Sure there is. The munchies at a bar, after you pay for your drinks. Wind power, after you invest \$750 million into the 20-odd fans. Solar power, at least for your i-Pod. (Well, ok... you can get a lot more power than that... you can power your house if you cover Rhode Island with collectors.) Waste oil fuel. Fuel from food, er, corn.

The depressing thought is that the laws of thermodynamics are the best possible case... not something imposed by grumpy engineers or greedy manufacturers so that you can't have your 200 mile per gallon carburetor.

Etmax

9/8/2010 4:05 AM EDT

:-) Damned back to the drawing board

hm

9/1/2010 11:23 AM EDT

This was really difficult article to read and to me it looked incongruous. In beginning law of conservation is revisited. This may be mystery only when you are in middle school. Also, as for plug-in hybrid the concept is explained very well by media – for average user, battery charged from mains will suffice their daily needs. Only when they exceed the range of battery charged, they need help of fuel. Also for any new technology, there are advantages and some disadvantages. Author misses to compare and contrast them from current and future prospects. I hope they are covered in part II. Please correct me if got it wrong.

R0ckstar

9/1/2010 11:34 AM EDT

Bob, you are my hero. It's people like you who are willing to brave ridicule from tree huggers & the like and make a personal sacrifice by buying up extra gas every time you fill up, removing just a little bit more of the finite fossil fuel supply than others are willing to, causing the price to go up, making green energy that much less uncompetitive. Doing the right thing isn't always easy, but you're sticking to your guns, and that's an inspiration to us all!

Bob Lacovara

9/1/2010 1:30 PM EDT

ROckstar, thank you kindly. I take your comment exactly as stated, as praise. I would like to point out that precisely because fossil fuels are a finite commodity, there is little point in extreme measures of conservation, because sooner or later, we surely will run out of the asset. What shall we do then? I'm not certain, but I doubt that wind power or solar energy will play much of a part.

On the other hand, "finite" doesn't mean "runs out next week". The US holds enormous coal resources. True, the coal is sulfur-laden, and even I would insist that before using a liquid version in consumer vehicles that the sulfur be removed. No one needs acid rain. At a price, of course. Ditto for US uranium reserves... it makes a mess digging it out (in places of low population) and it must be stored after use, but anyone not clear on the virtues of nuclear power can talk to the French. They seem to like it. (By the way, the waste product of a nuclear reactor is dangerous for what? 3000? 6000? years? How long is the waste from a fossil fuel plant, the ash, dangerous? When it is full of concentrated heavy metals: forever. Take your choice.)

By the way: fossil fuels are just the original solar power, aren't they? ;-)

Duane Benson

9/1/2010 11:56 AM EDT

To me, larger vehicles like monster SUVs are really the only place that a hybrid makes much sense. If you can take a vehicle from 12 mpg city (more realistic than the 15 stated) and turn that into 20mpg city, assuming a 200K vehicle life, 50% in city driving and \$4.00/gallon gas, you save \$13,000 over the life of the vehicle.

On the other hand, taking a 98hp 35mpg car and turning it into a 45mpg 134hp hybrid, saves you only \$2,500, given the same assumptions (only twice that if you assume the same mpg boost comes on all 200K miles). Using a hybrid essentially as a means to increase horse power is not a "green" way to go. Much better would be to forgo the \$10,000 extra power system and simply drive the 98hp 35 mpg car around.

Small vehicle hybrids don't make economic nor environmental sense. Large vehicle hybrids can help as a stop-gap until we really solve the fuel problem.

Bob Lacovara

9/1/2010 1:35 PM EDT

For those of you interested in problems to ponder, here are two. 1) Why do we ship stuff cross-country in tractor trailers? Why doesn't almost everything going more than 100 or 200 miles get placed on a freight train? Or does it already, and I am unaware of it? 2) How much energy is used by daytime driving lights in the US? The answer can be express in units of 1000 MW power plants if you like.

HankWalker

9/1/2010 2:04 PM EDT

Since this is EE Times, can't we just explain that the motor/generator, battery and transmission form a low pass filter that allows the ICE to remain at its optimal operating point much of the time. The designer can trade system cost (corner frequency of the filter) vs. fuel economy. Or from a mechanical engineering viewpoint, that the electric motor provides the low end torque, eliminating the need to oversize the ICE.

Bob Lacovara

9/1/2010 2:13 PM EDT

That's amusing: it is a correct and succinct means of describing a hybrid vehicle. I'm going to run it past our chief mechanical designer, who will undoubtedly growl at me. Very good. I like it.

selinz

9/1/2010 2:06 PM EDT

The assertion that "since we are running out of gas eventually, why bother trying to conserve" is surprising for me to see on a site that is presumably inhabited primarily by engineers. I drive a Honda Civic Hybrid. Now to be honest, the only reason that I bought it was because it looks like a regular civic (couldn't bring myself to drive a prius) and it lets me drive solo in the carpool lane (legally). Before this vehicle, I was perfectly happy with my Cadillac Seville which would average 23mpg. The Hybrid costed about \$3K more than a comparably equipped Civic. And I got a \$2500 tax break. I've put 140K miles on the car since December of 2006. 140K divided by 22mpg = 6363 gallons of gas. That means that in about 3.5 years, I've saved about \$10K in gas cost. NOt to mention the enjoyment of passing jillions of vehicles while in the carpool lane. I'm guessing it saves me 20 minutes/day. So that means I've saved 210 hours of drive time since I've had the car. I average more than 75mph. The car can easily do over 100mph and I can out accelerate most SUV's and small cars.
I do recommend that people do the math...stick it in an excel spreadsheet. But it's important to have correct numbers.
FYI, I had a 1970 FJ cruiser when I was in AZ and loved it. But I rarely drove it to work. It was suited for offroad and that's how I used it. I believe the new FJ's actually get worse mileage than the old ones (one of the industry's worse gas guzzlers, particularly when you consider what it can carry and what it's capable of).

Let's try to get our facts straight.

Bob Lacovara

9/1/2010 2:26 PM EDT

Selinz, why is this comment on conserving fossil fuels surprising? What is the goal of conservation? Not to extend the availability of a finite commodity by a month or two out of two hundred years, surely. In point of fact, unless you stop using fossil fuels entirely, they cannot be conserved, only exhausted. Whether this happens in 2090 or 2525, what difference does it make? They _will_ run out and the people who need fuels at that time had better come up with a solution. Note well: they have to come up with a solution. We aren't responsible for solving their problems, and they wouldn't take the solution anyway. My comment on burning all of the gas I can is partially tongue-in-cheek, but not entirely. Let us conserve what can be meaningly conserved, and forget about conserving for the dubious sake of conserving. As for hybrids, I'm pleased that you are satisfied with yours. (For a fact, it's hard not to be pleased with a Honda or Toyota.) But what if someone wants to drive a Seville, and not a Honda? They at least have the option in the US, at a price, of course. Curiously, I saw a 1970 FJ Cruiser for the first time yesterday, as I happened to overtake it on an interstate, wondering what it was. The driver waved cheerfully at me in my FJ, and recognition struck. For the record, it gets 21 on the highway, maybe 18 in the limited city driving it gets. Hardly the industry's worse gas drinker: have you looked at what a Hummer drinks lately? Plus: I like it.

dirk.bruere

9/1/2010 3:10 PM EDT

Diesel engine 2.0L VW Golf - 55mpg average, 40 in city driving. Who needs a hybrid?

Bob Lacovara

9/1/2010 3:48 PM EDT

This too is a good point. If you are happy with your fuel economy, you are unlikely to change your vehicle unless it provides some outstanding increment in utility or some other factor high on your priority list. I have a 30 mpg Corolla, and it would be nice to have a 55 mpg something else, but as soon as the cost of the change is weighed, I sit with the Corolla. When it becomes old and tired, then priorities, and current technology, can be evaluated.

jg_

9/1/2010 3:33 PM EDT

Hybrid : a composite of mixed origin; So Hybrid means many things, and there are a wide range of 'Hybrids'.
Certainly it makes sound sense to go after the really 'free' energy, which is braking energy, and also easy waste energy, which is 'Traffic Light' / Gridlock energy.
So that points firstly to & Stop/Start or Stop/Go technology. A quite mild hybrid on the ICE/Battery Continuum. Next, you might like to nudge up the Electric portion: The battery, a bit, to better collect the regen braking, and the Motor, a bit, to give better acceleration, and drop the kg's of the main ICE. Less weight = less fuel.
Expansion beyond that point, becomes dependent on the range and usage.

Test_engineer

9/1/2010 5:47 PM EDT

Hybrids are for the guilt-ridden liberal set. Conservatives, like yours truly, will never drive some Mickey Mouse, Rube Goldberg contraption. I want power, and lots of it on the highway just in case I have to get out of a bad situation fast.

http://www.lulu.com/spotlight/poconoarmchairreview

9/2/2010 2:48 AM EDT

Run out of oil? Hmmm. The moon Titan has big lakes of oily hydrocarbons. That says oil may be geologic, not just biologic. That also means Earth may have a lot, lot more oil than we realized--it just happens to be trapped way down below, so that most life has, over the ages, learned to be happier without that much oil being around. And THAT means we're likely to make Earth uninhabitable long before we run out of oil. I'm all for replacing oil as a power source with something more compatible with my biology. Hybrids won't do it. But because I can make 700 gallons of ethanol from an acre of fresh sugar beets, I'll be happy to drive an alcohol burner. (I'm guessing ethanol is a better way to store solar power than batteries.)

http://www.lulu.com/spotlight/poconoarmchairreview

9/2/2010 2:51 AM EDT

And of course when I say my body isn't that compatible with oil, I mean petroleum oil, not animal or plant oil.

Bob Lacovara

9/2/2010 8:22 AM EDT

Hm. Didn't know about Titan. Seems like a good NASA project: they need one about now. And I also note that the US has enormous quantities of shale oil in addition to rather mephitic (well, sulfurous) coal. In the one case, recovery is more expensive than your usual oil well; in the other you must pay to get the sulfur out. But the energy supplies are there, they just won't be as cheap as what's available now.

prabhakar_deosthali

9/2/2010 6:48 AM EDT

If we can convert more efficiently that 1KW per square meter of Solar Energy , falling on our earth ,into direct Electricity, to charge those batteries while the vehicle is running on gasoline during the day time, and drive the vehicle on batteries during the sun-down time then that will be a true Hybrid vehicle which will use the free energy coming from the Cosmos.

Bob Lacovara

9/2/2010 8:40 AM EDT

That 1 kW/m^2 that prabhakar_deosthali mentions is under the most optimistic conceivable conditions. One site that has some irradiation values under a variety of realistic conditions is http://sunbird.jrc.it/pvgis/apps/radday.php, others are available. On the average, if you can get 150 W/m^2 (in the US) you may consider yourself lucky. This isn't to say that solar energy isn't an important market, but I doubt that serious power will be available at rational cost.

Richard_P

9/8/2010 8:58 AM EDT

So you think it's unlikely any advances in Solar are likely to decrease the cost per kWh but you are quite happy with the idea of spending vast amounts drilling for oil and processing oil shales?
So far you seem set against anything new and entrenched in the past - are you funded by the oil companies? Whats' wrong with being more efficient in our energy use.
I'm sure that if rationing of energy was introduced then everyone would suddenly take much greater care how they used it.

I would have thought that the US would be embracing alternative energy sources and increasing efficiencies.

The argument that as oil resources are finite there's no point in trying to conserve them is one that even my children know is daft! ...they're 4yrs and 9yrs!

Richard_P

9/8/2010 9:00 AM EDT

Oh, and for nuclear was it's about 100,000 years - seems Sweden has a problem with this
http://news.bbc.co.uk/1/hi/sci/tech/4597589.stm

Bob Lacovara

9/8/2010 10:47 AM EDT

Richard_P, there will undoubtedly be advances in cost/kWh for solar power. Trouble is, when? How much? The "vast amounts" spent drilling for oil are reclaimed from the folks who buy the oil... everyone gains. (Even the government gains from the taxes for doing nothing, and in some cases, the government gets the lion's share.) And further, the shale oil is there, right now. If you wait for sufficient advance in solar power, you may be waiting in the dark.

I'm hardly against anything new, and I am not entrenched in the past. But I lean on the past a great deal, since understanding where you have been helps you shape a course forward. There's nothing wrong with seeking efficiency, unless we are talking about efficiency for the sake of efficiency alone. What's the point in that? Every action or design choice we make is weighed by priorities. Eventually, the cost of increasing efficiency is a price that no one will pay. Design is about choosing a good cost/efficiency point, not chasing efficiency at the expense of form, function, cost, etc...

Your children, at 4 & 9 years, may be excused for holding an irrational opinion. Here's a more rational take. Every gallon of gas that I use deprives someone, eventually, of the use of that gallon. I don't know when that will occur, or to who, or why they will need it, and whether or not they will have alternatives. It will occur at a point well beyond my exit from this world, and the point can't even be pinpointed to within 100 years. In short, saving that gallon may make some people feel good: go ahead, save it. But "makes me feel good" is not a sufficient (or even necessary) reason for me to take an action. For my part, my need seems to exceed the need of an unknown person, an unknown number of years in the future, for an unknown purpose. I don't expect everyone to agree, but it's not daft.

Nope, I don't work in the oil patch, but it wouldn't bother me. I'm just an old capitalist iconoclast, is all.

mixed-signal

9/2/2010 9:48 AM EDT

So far the article has not discussed the overall well to wheel efficiency, but has only posited that "it must not be that efficient" due to potential (unspecified) heat losses. Without overall efficiency presented, this is just an opinion. The 134hp discussion, while probably correct that it's too simplistic (e.g. was it measured at the wheels?), it's beside the point on the efficiency discussion.

The author has also not discussed regenerative braking (energy recovery) or that the ICE is (usually) shut off when at stop lights. These are big reasons why hybrids often have higher mileage in city than highway driving, and a significant source of improved efficiency.

As to the comments on conservation. Come on, since when is it not better to save some money to put to use elsewhere. This is not to mention the destabilizing effect all this cash flow has on many oil-rich countries.

A more on-target comment would be that the economic efficiency is not there since the hybrids are more complex. The comments on high efficiency of the new diesel engines is spot on. These probably present a much better overall trade-off of fuel and economic efficiency.

MrDave

9/8/2010 9:51 AM EDT

Co2neutral:

Before the car can be stopped it had to be propelled. That initial propulsion came from the powertrain. Recovering some of that energy spent propelling the vehicle by using regenerative braking is not finding another energy source. It is reconverting energy that was already converted into motion- by the powertrain. In effect we still have 100% of the energy derived in propelling a non-plug-in hybrid came from the gas tank.

Safety is a real issue. Not too long ago, within 50 miles of each other here in the Detroit area, there were two accidents involving head on collisions. Both were at combined speeds of 50+mph. One involved two F250 size pickups where everyone walked away with some injuries. The other involved a van and an Aveo. The Aveo was sitting at a stoplight and had 4 teenagers inside. None of them survived. The driver of the van was not even scratched.

Safety is an issue. Especially if you were the parent of one of those teenagers. We should not be paranoid about stuff, I agree. But we should take reasonable precautions. Some consider purchasing a larger vehicle “reasonable”.

Salio

9/2/2010 1:44 PM EDT

I believe that hybrid electric vehicles (HEVs) are one of the modern technological advances in which we can use to help reduce some of the pollution we emit in to the environment. HEV has come a long way from its inception a decade or more ago. There is no question that in order to improve efficiency of the overall system, the least efficient component in your system needs to be optimized. In a car that component is the internal combustion engine (ICE). Typical efficiency of an ICE in a conventional car is about 15%. So most of the gas you put in your car goes to waste and only about 15% of it actually is spent in getting you around. Wouldn't we want to get the most for our buck by getting as much as we can out of the gas we put in to our car? I want to get every bit for the gas that I put in my car. One of the many solutions out there is HEVs. HEVs use power electronic converter(s), battery pack(s), and motor (s) to improve the efficiency of the ICE by running it at its optimal point and have a motor supply additional power that is required by a car. The overall efficiency is improved and since the motor is doing most of the work in the drive train there are less emissions in the environment.

I think HEVs are being side stepped by electric vehicles (EVs). Though EVs are kind of expensive right now but as technology is improved and the cost is brought down, they will become more attractive to the general public.

Nations around the world look to the US to lead. We must lead by example by doing whatever we can to lower the emissions in to the environment. If that means we drive less, drive more efficient cars, or what have you then we should do them.

One may say we'll what benefit is it going to be if I drive a hybrid. Every little bit counts when we are talking about a nation like ours, which has more than 300 million people. We should care for the environment we are in by doing whatever we can to improve it.

Lloyd P

9/2/2010 6:40 PM EDT

Series hybrids (Internal Combustion engine to generator to battery to traction motor) have been around a long time, and have proven themselves. They are called diesel-electric locomotives.

Properly sized, the IC engine handles the average propulsion requirements, with some losses due to the efficiency of the energy conversions involved. Surge capacity is handled by the battery-traction motor combination. That way, honkin' big V-8 power can be provided with a relatively small four-banger running at it's peak efficiency point. In an IC powered vehicle, the engine is sized to meet peak power requirements, but loafs most of the time.

By using regenerative breaking, energy which is otherwise lost to friction & heat can be recovered and stored in the batteries.

So the primary advantage of a series hybrid is that it optimizes the efficiency of the IC engine, while providing betterresponsiveness than the small IC engine alone.

Are they cost effective? That remains to be seen.

HereBeDragons

9/2/2010 10:30 PM EDT

A few people have mentioned the saving in pollution because of increased efficiency. Unfortunately, because of mining the ore, refining the steel, etc etc. a car will produce more pollution just in its manufacture, than it ever will in its entire lifetime of being driven. Maybe manufacturers should reconsider their almost compulsive-obsessive desire to build a new model every year? Or buyers should look at their "keeping-up-with-the-Jones's" attitude?

Bob Lacovara

9/7/2010 9:52 AM EDT

HereBeDragons raises an important point, albeit more social than engineering. If, as is claimed, the production of a car produces more pollution than its operation, then clearly those of you who fancy yourself to be green should look at that issue more closely. I think the favorite means of changing people's behavior is to begin an ineffective "education campaign" while raising taxes on the now-frowned-upon activity. This doesn't always work the way intended. As another example, consider the hue and cry for alternate electric energy sources. Far fewer would be needed if everyone who uses an air conditioner set it up about 5 degrees. I don't see that happening voluntarily. Nor do I see people buying less in the way of new cars voluntarily.

Etmax

9/8/2010 4:15 AM EDT

Has anybody read about the car described in New Scientist (no doubt other places as well) that uses a catalyst to break down water into H and 2O then feeds that into a fuel cell that provides power for motion and charging of the batteries. The fuel cell by-product is water, so you need a little bit of water to cover losses and a replacement catalyst block every so often. The catalyst canister is swapped out and reprocessed using solar generated electricity. Supposedly range is 300-400 miles per canister. This would be much better than a hybrid as there would be no hydrocarbons involved, the time at the fuel pump (read canister supplier) would still be only a few minutes, and the vehicles would need almost no gear box (read losses) due to say motor per wheel technology. SUV's would have bigger canisters & motors. I'm sure the article left something out, but it seems to tick a lot more boxes than hybrids or plug in EV's do.

omoptek

9/8/2010 6:02 AM EDT

I'm working every day for European companies working in the optimization area for IC engines but personally I'm driving since October 2007 a BMW IC engine of 177hp running at a top speed of 144 mph with an average consumption of 55 mpg.The
new efficient dynamics engine coming is giving 184 hp 145 mph and 57.5 mpg. The american automotive industry is just 15 years late.

co2neutral

9/8/2010 7:46 AM EDT

These posts are mostly expressions of ignorance, as engineers you should do better. there are som many mistakes here. However I understand why, because the article has mistakes in it. it is incorrect to state that 100% of the energy to propel the vehicle comes from the fuel. some of that energy comes from the braking system. that energy is unavailable in an nonhybrid vehicle to propel it.
And this safety nonsense, give it a break. stay at home and don't drive if you think the roads are that dangerous.

MrDave

9/8/2010 10:09 AM EDT

Co2neutral:

(initailly submitted to the wrong comment. :(

Before the car can be stopped it had to be propelled. That initial propulsion came from the powertrain. Recovering some of that energy spent propelling the vehicle by using regenerative braking is not finding another energy source. It is reconverting energy that was already converted into motion- by the powertrain. In effect we still have 100% of the energy derived in propelling a non-plug-in hybrid came from the gas tank.

Safety is a real issue. Not too long ago, within 50 miles of each other here in the Detroit area, there were two accidents involving head on collisions. Both were at combined speeds of 50+mph. One involved two F250 size pickups where everyone walked away with some injuries. The other involved a van and an Aveo. The Aveo was sitting at a stoplight and had 4 teenagers inside. None of them survived. The driver of the van was not even scratched.

Safety is an issue. Especially if you were the parent of one of those teenagers. We should not be paranoid about stuff, I agree. But we should take reasonable precautions. Some consider purchasing a larger vehicle “reasonable”.

AlexKovnat

9/8/2010 8:36 AM EDT

I wouldn't mind having a hybrid electric vehicle like the Prius for several reasons: One, when you crash into your 60's, come to realize that a problem with "muscle" cars is that they offer speed and acceleration you're never going to use. How many of us actually need to accelerate to 60 miles per hour in only 4 seconds, or drive 150 MPH?

Now, about hybrids: In my suburban subdivision, I'm going ~25 miles per hour to get from my driveway to the point where I turn onto a major street. I consider it wasteful to fire up an engine capable of taking my car to 75 miles per hour or more, when I only intend to go 25 MPH (maybe 30 if I feel like speeding) while driving within my subdivision. Once you get to the main boulevard, then you can fire up your engine and drive 40, 50 or 60 miles per hour.

With a Diesel engine, you don't have the awful fall-off in efficiency at low load. Therefore, you don't need expensive hybrid technology.

Unfortunately mother nature tends to frustrate us here, owing to the Diesel's problems with particulates and oxides of nitrogen. In Europe, they're going to NOx control systems that require using urea to neutralize said pollutant, as a 3-way catalytic converter won't work with engines that use overall lean fuel-air mixtures. This includes Diesel and "lean burn" non-Diesel engines.

This is why I believe the hybrid is here to stay. For those who need an SUV, i.e. families with children, GM makes a good integrated hybrid transmission system based on the two-mode concept. If it can be proved there is redeeming social value to reducing carbon dioxide emissions, then tax rebates should be offered to compensate people for the added initial cost of such systems. Furthermore, if global warming is an actual problem and our way of life is the cause of it all, there should be a high tax on motor fuels to incentivize people to purchase more fuel-efficient vehicles and live energy-economical lifestyles.

Jack.L

9/8/2010 12:50 PM EDT

As an engineer, I lost a lot of respect for fellow engineers reading this reply. Everyone seems to be missing the point. This is not about money, it is about preserving the planet such that us and our children can enjoy it.

Wrapping yourself in steel is not going to matter one bit if you can't breath the air.

Think people! We cannot keep going the way we have been going.

Bob Lacovara

9/8/2010 1:15 PM EDT

Semiman_#1: with respect, everything is about one or two things: money, or power. When little or no money is at stake, or little or no power, then people may or may not take the wider viewpoint. But once money enters the equation, and there's a value that can be assigned to an action, then most people weigh it very heavily. This is why capitalism works pretty well, and socialism works pretty poorly. In the former case you have an unambiguous metric to guide your actions; in the latter you are at sea. In the end, people mostly work to their own benefit, and that of their family. The people who invariably defer and work to the good of their fellow man we call saints. Saints do not make up a large voting block.

MrDave

9/8/2010 1:17 PM EDT

Semiman_#1:

I think that automotive engineers are putting forth a considerable effort to make sure that the air is breathable for us and our children.

The air in cities today is much cleaner that what it was 20 years ago - thanks to engineers. Yes, the federal government made regulations but it was engineers that first said to the legislators that is could be done and then, made it happen.

As in all engineering we look for and develop reasonable responses to problems. What we consider reasonable depends on what priorities we have and what resources we have available.

Those priorities are based on what we beleive to be true. In your case, you think that the sky is falling... I am not so sure that the rest of us think that way.

Maybe you could write an article on why you think the sky is falling. I would love to read it.

Bob Lacovara

9/8/2010 1:43 PM EDT

MrDave (hey, did you change your handle?) I am in close agreement with you. To highlight your case, I'd like to point out what happened when the government decided that it could be a plumbing expert. Toilets using 5 or 6 gallons (20 to 25 liters) were to be flushed, and replaced with units that used 1 gallon. Sure. Ok... we live on a planet mostly covered with (salt) water (should be called Ocean, not Dirt), and we flush with sweet water... I acknowledge that some toilets are rather far from the ocean... but since we want our own toilet don't want to go to the Jersey shore to use one, we should probably not waste water. Ok. Trouble is, that for years the toilets designed for 1 gallon/flush didn't work very well. So what happened? Well, they got flushed more than once per use. Savings? I guess so, some. So, if Congress is going to mandate the 100 mpg carburator, I think they should tell us how to build it, too.

In any event, I heartily concur with your notions. Engineers have made great strides in reducing the use of resources while maintaining functionality (LED lighting is coming along nicely, thank you) and these improvements are every bit a valid expression of engineering excellence as the first ideas for a new technology.

Hm... rather far afield from hybrid cars. BTW, that transmission in the Prius is an act of genius whether or not a person likes the vehicle.

MrDave

9/8/2010 4:15 PM EDT

Bob:

I am not thinking that salt water makes much sense in that it would corrode the working parts of the toilet fairly quickly. And we have enough trouble keeping the thing from running continuously...

Besides, waht would the salt do to a water treatment plant? or to the septic tank biology? or the subsquent ground water?

Bob Lacovara

9/8/2010 4:35 PM EDT

MrDave, there's no doubt that using salt water in toilets would create more problems than it might solve. But in places where fresh water was at a premium, and salt water was readily available, one might consider using it. I am thinking of Caribbean islands... my point was more that although there are plenty of places where water might well be conserved because it's not in a long supply (California in places) there are others where its available almost without limitation (I am fortunate to have a well on the side of the Blue Ridge mountains, and no near neighbors). We must fit solutions to needs, and not "fix things that ain't broken", right?

MrDave

9/8/2010 5:03 PM EDT

Bob, Indeed. I get your point. We are in agreement.

9/13/2010 4:25 AM EDT

What everyone in this thread seems to miss is that the fundamental activity that we engineers perform can be described by a single word:

optimization

Furthermore, as engineers, we all know that the result of any multi-objective optimization depends entirely on the objective function which is to be optimized.

For some in this discussion thread, the weighting is heavy on safety. Others, comfort. Still others, power, convenience, or cost of ownership. And for a few, the weighting is heavy on efficiency, environmental cost, sustainability, stewardship, or national security.

The fact that all of the commenters in this group are not on the same page is simply a consequence of the subjective weights we carry. However, such a diverse set wouldn't even be possible if it weren't for the fact that technology has made it possible. Would safety even be on the table if it weren't reasonably affordable to boost safety? Likewise with power. And likewise with efficiency and sustainability.

It is clear that hybrids and electric vehicles still require some significant sacrifices along certain axes of the optimization space. But this will almost certainly not always be the case.

It should be obvious to all that the time evolution of the automotive space is extremely unlikely to drive harder toward internal combustion technologies and far more likely to drive toward some form of technology that involves electricity and electric motors. The rate at which the automotive space is driven toward some new norm may be too fast for some and not fast enough for others, but it's hard to ignore the fact that electricity-based vehicles are coming. Using our own U.S. based weighting (which is heavy on luxury, safety, and convenience), the rate would appear to be slow. But the people living in countries like China and India measure the problem differently and are likely to drive the solution space more radically and rapidly than we do in the U.S.

Bob Lacovara

9/13/2010 9:57 AM EDT

Well now. I cannot say that I disagree with graduatesoftware. Except for one point, a tendency that surfaces from time to time in discussion. I agree most emphatically that a set of rational engineers, holding different weighing functions, or priorities, will usually arrive a differing solutions. Of course. And further, they will often understand how each arrived at his decision.

Ok. But what needs to be watched carefully are statements of the form: "It is clear that hybrids and electric vehicles still require some significant sacrifices along certain axes of the optimization space. But this will almost certainly not always be the case." This isn't objectionable in itself, and is even plausible. However, I would not care to use the prediction that electric car technology will drastically improve. There's a name for a person who shapes their actions on the prediction of a desired future state: it's not "engineer" but "gambler". In other words, I will be willing to adjust my solution to my transportation problem when electric cars don't cost 1.4 times what an ICE vehicle costs, or go a little further than the corner store before needing an 8 hour charge. But until then, since these improvements do not exist, I have to sit tight with what I have, for the problem I have to solve every day. ...more...

Bob Lacovara

9/13/2010 9:57 AM EDT

...con't...
It is not merely in this context that a sort of wishful thinking is substituted for hard and cold facts. "The fossil record is has great gaps...as soon as we find the missing links, all will be proved." Agreed. In the meanwhile, the data is non-existent and it's only rational to act that way. "As soon as this new carburetor is perfected, we'll have 75 (100? 150?) mpg autos." Right. Don't hold your breath. "As soon as some manufacturing arrangements are worked out, 4 passenger general aviation aircraft will cost only twice (1.5, the same...) as a car." Yea. Right now, you can get a really nice 4 place airplane for about \$75000 per seat, new. I doubt any technology will make the price decline significantly. The issue here is that although we can do all sorts of neat things, and more are found on a continuous basis, you are on thin ice when you shape your actions towards a particular innovation becoming reality in a specific, near time frame. Assign your priorities to demonstrable conditions, not hopes and wishes.

On the other hand, if you do become good at these predictions, forget all this technology stuff, and settle down to the stock market.

DrQuine

9/13/2010 8:04 PM EDT

Exchanging my 30 mpg Toyota Corolla for my 50 mpg (lifetime average over 88,000 miles) Honda Civic Hybrid has saved a lot of gasoline without violating any laws of physics. First, the engine turns off when it isn't needed (that growling SUV behind me at the red light is still gulping gas). Second, the ICE is able to work in a more efficient RPM range and store some energy in the battery for later use. Third this offloading of power enables peak horsepower (ICE + battery) to exceed the power of the ICE alone. Fourth, regenerative braking allows me to recover energy when braking for reuse later. Fifth, the regenerative braking saves wear and tear on my brakes - which have lasted three times longer than on my old Corolla. I earned back the extra cost of my hybrid in gas and brakes years ago. Finally, a calmer driving style reduces speeding tickets and road rage - a benefit that would be great to see on a broader basis.

Kaiser Silicon

9/14/2010 5:45 PM EDT

Something that I think hasn't been done is to try and optimize hybrids for highway driving. They are tuned quite well for say down town Manhattan, but aren't tuned for say open road driving.
.
The statements concerning conservation of energy is of course correct. However, I do think that there are possibilities out there that haven't been explored. Prime example is thermo-electric generators that capture heat energy from the exhaust and use it to keep the battery charged up. There is, of course, more weight to be hauled around as a result, but it might be possible to improve overall energy efficiency.
.
Another possibility, at least for short commutes, is to run the car in an all-electric mode. And then on the roof, hood, and trunk, have some of those flexible solar cells, and use them to at least partially recharge the battery. It isn't a magic bullet, but it might be able to bump up the efficiency some.

mr88cet

9/15/2010 10:10 AM EDT

Being a Prius owner and an engineering geek, I've studied the Prius' drive system a bit. It's worth pointing out that there's really no one single factor that gives it its high mileage; it's a combination of many factors.

However, there are two factors that are probably the biggest contributors. One is a high-speed mechanism (i.e., it improves mileage at high speeds), and another is a low-speed mechanism.

At high speeds there's only so much that electrics can do to help. The main thing you can do is just simply reduce aerodynamic drag. The 2010 Prius has a drag ratio of about 0.25 - quite little drag. This is a lot of the reason why, as you mentioned, hybrid versions of pure-gasoline cars often don't get much better highway mileage: The only way to improve that substantially is to change the body design.

At low speeds, the main thing the Prius does is use electric drive as much as possible. That helps because you simply can't create an ICE that burns at 15 miles per hour 1/3 of the fuel as it does at 45 miles per hour. ICEs have a lower limit on how few *gallons per hour* they can consume without shutting off completely. An engine therefore can't rack up very many *miles per gallon* unless without also racking up a fair number of *miles per hour*. In other words, you're not going to get very good mileage in low gear, so you have to simply shut the engine off at low speeds.

After that, yes, keeping the engine in its ideal RPM range, regenerative braking, and so forth also help. After that there are some complicated balancing acts, such as when it makes sense to run the engine just to simply keep it warm, since a cold engine is inefficient.

pixies

9/16/2010 1:16 PM EDT

Very provocative yet informative post, just look at the heated debate. Two points:

First, we are not in an energy crisis, we are in a climate change crisis. There is plenty of energy to be had on earth, fossil or non-fossil, the problem is how to extract them without pollution or cause global climate change.

Second, I firmly believe that the cost of a thing tracks pretty well the energy used to produce it. So if a hybrid cost more, the overall energy footprint is higher than a regular car. The the energy saving throughout its life time had better off-set the increase sale price otherwise it makes no sense.

625kinc

9/16/2010 4:49 PM EDT

Checking with the EPA web site, 103 Prius averaged 49.1 MPG with a range from 35 to 60 MPG. Given a normal distribution of annual miles with 15,000 being the mean, those who drive more, over half of the typical drivers, can save a bundle. For example, let's compare the Prius to the FJ Cruiser:

50 :: 19 MPG combined, EPA standard testing
\$22,800 :: \$23,400 Toyota 'starting' prices

Right off the bat, the 'hybrid premium' has disappeared. For a commuter car, one that takes one or two people to and from work, typically in an urban or suburban driving experience, the EPA calculates:

\$816 :: \$2,146 relative fuel costs

Since I'm doing 20,000 miles per year, the savings are even greater. That is why I belong to the 'right tool for the right job' crowd.

The Prius is the natural choice for someone spending most of their miles commuting. In contrast, if someone is driving 15,000 miles a year towing a boat, they should have the FJ Cruiser . . . and an appropriate fuel budget. But we usually call these people "truckers" and unless they inspect or build bridges or water platforms, they seldom are engineers.

I have no problem with engineers who want to play "trucker" with their fun vehicles on the weekend. But trying to commute to and from work in one is the wrong tool for the job . . . like the old Soviet practice of using a hammer to drive screws.

Bob Wilson

Bob Lacovara

9/16/2010 5:06 PM EDT

Yebbut...

Why not compare the Prius used for commuting to something even larger than an FJ Cruiser? The Prius would look better still. If you don't want to compare the Prius to a tractor trailer, then you might choose a Harley Davidson, a Kawasaki, or a Yamaha or what-you-will. I see guys commuting on those beauties all the time, although it's not for me.

Ok. Let's be fair. You are quite right, who's going to commute in an FJ Cruiser? How about a comparison to a Corolla? Mine gets 28 to 31 mpg going about 60 miles round-trip a day. Toyota's web page says a new one is (base) \$15,450, and gets 26/35... adjust the numbers if they don't suit. What does the comparison look like then? BTW, when will the battery in the Prius have to be changed, and what will it cost? My Corolla is an '02, has 113K miles, and I expect another 113K, unless, of course, I buy a second FJ Cruiser to match my other.

These two vehicles, a Prius and an FJ Cruiser, are apples and oranges in a comparison. You note that the idea of the right tool for the right job is a good one: agreed. But there are more variables and requirements on a car choice than just what it costs to buy and run.

Bhola_#1

9/19/2010 3:33 PM EDT

I do not understand one thing, why to use word Hybrid for fuel efficint environment-friendly automaton. Any automation includes electromechanical circuits is a source of pollution..just my idea

vivekv80

9/21/2010 4:22 PM EDT

Hubrid cars are very ex[ensive, 30k if you factor in the amortized costs, getting a normal japanese car any time is the best option

9/25/2010 6:18 AM EDT

Bob Lacovara said: "There's a name for a person who shapes their actions on the prediction of a desired future state: it's not 'engineer' but 'gambler'."

This statement seems to reflect an underlying ignorance of the fact that **all** decisions are gambles. Engineers gamble all of the time (as do all people when they formulate a decision). The question isn't whether or not one is gambling when making decisions, but what knowledge and biases they bring to the gambling table and how each affects their likelihood of winning (however "winning" is defined in the given context).

Bob Lacovara

9/27/2010 10:19 AM EDT

Um, no... re-read my statement, which included the phrase "desired future state." An engineer makes decisions on the basis of gathering as much information as is possible, subject to constraints of time and budget. He adds in a bit of experience, and the result is called a "decision". That's how I might choose a capacitor: it's not much of a gamble. A gambler decides that, for example, the ICE is bad for a set of reasons. Then he performs an analysis that will tend to confirm his bias. He goes ahead, and makes a decision. The gamble is that his biases are correct or not. If they are not, too bad. If they are, fine, but why bother with any sort of engineering analysis? That's how, in some cases, exceedingly green individuals (or individuals of many other stripes) wander into errors: by doing what "seems sensible" or "feels good" or "looks right": in short, by avoiding the hard work of analysis, and merely gambling.