Ronin of the Spirit

Because reality is beautiful.

Chevy Volt analysis II

Well, after some thought (and the first comment I have ever had from someone who didn’t already know me) I want to revise slightly my stance on the Chevy Volt, and admit something.
I have a bit of a vendetta against the auto makers

I love cars. To me that makes me sound ignorant, so let me first say, what that doesn’t mean. It doesn’t mean that I love fast cars expensive cars. I love all cars. When I was around 9 my biggest dream in life was to own and operate a car company. A writer for Motor Trend explained to me that this would be very difficult because the day of the cleaver young man with a dream running a car company was over. Those men had worked so hard and built so much that the cost for admission into the small club of car makers was incredibly high. So I studied not only the way cars are put together, but the way they are made. It’s not enough to make a truly great car, you also have to sell it. Some of my readers might be naive enough to believe that making great car would ensure that people would buy it. Actually the public usually wrong, and often when right, they are so for the wrong reason/s. The public is like the most dangerous sort of person: the person who knows enough to think that he knows much more than he really does. A truly great car is a masterpiece. Engineering is an art as well as a science. In a truly great car every bolt and bit is like this single brush stroke of a great painting. Insignificant in and of it self, but participating together to make a masterwork.

I constantly in a desperate search for a car that not merely adequate for the mundane task of shuttling me from place to place but a car to wear the mantle of greatness that human endeavor deserves. If you misjudge me, you will assume I mean some car that does everything. It goes ridiculously fast, in sumptuous comfort, costing pennies in fuel and nothing in maintenance. I do mean all that. I mean all that and this: it must me cheaper than dirt. Its not enough to make art. Art was meant to enjoyed. There is something about a beautiful painting, a real classic, only ever seen by the obscenely wealthy, that robs art of its joy. Art isn’t just for the people who can afford the education that tells them why it is right for them to like it. Art is for any person willing to be moved by it. A French farmer will not tell you that he likes his 2CV because it began the second epoch of the world auto industry (though it did) he will tell you he likes it because it is cheap to buy, cheap to run, and cheap to fix. A real classic gets into peoples’ lives in a gritty low-brow way. A first year art student can tell why the Mona Lisa is good art. But a first grader can tell you he saw it on the back of his cereal box.

I am not bothered by the concept of hybrids plug-in or otherwise. The theoretical advantages of a system which includes different methods of energy production, storage and utilization cannot be argued. Nor do I have any doubt in the ability of our inventive species to come up with a way to make these wispy theories flesh and blood. I even believe that production engineers and financial analysts can find a way to me this cost purchasers little, but benefit producers much. What I doubt, very much, is that the Chevy Volt is going to be the car that reflects the above. In fact, I believe strongly that the designers of the Chevy Volt aren’t even trying. Worse still, I think management has purposely given design specifications that will not clue people in to what the designers are capable of, lest the consumer develop realistic expectations about price and performance.

Here is the good about the Chevy Volt:
(1.) Plug in capability
(2.)Attempt at power-train maximization
(3.)Fuel economy

Now, I’m going to list the great successes . Basically each of these relate to the car succeeding as art. . The bench marks are…
(1.) The Model T
(2.) The Citroen 2-CV
(3.) The Jeep
(4.) The Beetle
(5.) The Mini
(6.) The Ford Model V8
(7.) The Honda Cub (a motorcycle)
The above vehicles didn’t succeed in the market, they created it. In the above seven cases, there had been vehicles that incorporated some or all of the features that the above embodied, but while the predecessors had been periphery sellers, many of these models were produced for more than 25 years (some more than 50, and the beetle for more than 75 years).

The Chevy Volt fails for the following reasons:
(1.) Totally inadequate chassis. 2600 lbs is far, far to fat for a 4.5 passenger vehicle whose selling point is fuel economy.
(2.) Lack of direct linkage of engine to drive engine. In cruise this has less losses than a genset to motor system. Since highway mileage is done at cruise this is clearly necessary. (My kudos to the commenter who pointed out that I first complained that it had this. I was wrong, the Volt does not share technological parentage with the Toyota Prius. The linkage is a good idea, Toyota simply made the task more complicated that it should be.)
(3.) Near total lack of aerodynamic refinement. Bob Lutz freely admits the Volt is more aerodynamic backwards. (He assures us this will be fixed.) This is not task here is not making it more slippery. The task is making people like aerodynamic cars (Look up the Chrysler Airflow). The ideal place to introduce a whole new concept of the way a car should look is with a new power-train because people have less expectations.
(4.) The use of a four cycle engine. With an advanced power train controller (which the Volt has) there is no reason not to use a 2 cycle engine. The computer can make a 2 cycle as clean as a 4 cycle with 80% less moving parts.
(5.)The use of a battery pack to store energy instead of almost anything else. Chevy says the open road performance of the Volt is 50 mpg. Using that number as a basis for energy requirement, if we figure its 40 mile electric range that means that it takes .8 gallons of gas or about 5 lbs. As I mentioned the real world efficiency of batteries verses gas (15% loss for electric motors versus a 75% loss for gas engines) plus the joules per second of heat in gas versus the joules per second of the electricity means after calculation that li-on cells hold about 1/24 the energy of an equal weight of gasoline. 5 *24 = 120 lbs. Plus the weight of the motor.
Using a small high efficiency gas engine as the auxiliary rather than a battery and electric motor saves weight, and can increase fuel mileage.
(6.)I stand by my original statement that plug-in hybrids are not necessarily better for the environment. According the scientist contacted by Noel Parrin in his book Solo (about his electric car journey) the magic number is 80 MPG. Power plants burn fossil fuels too. Make a car that gets better than 80 MPG and you are making power on your car with less pollution than the smoke stacks at your local coal plant. Electric isn’t zero pollution. Its the pollution of 80 MPG.

The Chevy Volt is a good concept car. Its just not nearly as good as it needs to be to change the world, which is what many suggest it will do.

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November 26, 2007 - Posted by | Uncategorized

2 Comments »

  1. Your Volt Failings…
    >>>>>>>>>>>>>>>>
    (1.) Totally inadequate chassis. 2600 lbs is far, far to fat for a 4.5 passenger vehicle whose selling point is fuel economy.
    >>>>>>>>>>>>>>>>

    What do you object to most of all ? that the car is heavy and fuel efficient, doesn’t that just make it clear how inefficient regular internal combustion engine, ICE, powered cars are. BY th way ICE cars are more normally only 15% efficient, unlike the 25% you say they are. Argue that one out with Toyota, the most succesful car company at the moment.

    >>>>>>>>>>>>>>>>>>>>>>>>>>>
    (2.) Lack of direct linkage of engine to drive engine. In cruise this has less losses than a genset to motor system. Since highway mileage is done at cruise this is clearly necessary. (My kudos to the commenter who pointed out that I first complained that it had this. I was wrong, the Volt does not share technological parentage with the Toyota Prius. The linkage is a good idea, Toyota simply made the task more complicated that it should be.)
    >>>>>>>>>>>>>>>>>>

    Toyota merely took an existing device, the epicyclic gearbox, as used in many differentials and put it to another use, in so doing removing all other parts of the gearbox by creating a CVT. Also I can’t see how genset losses can be more in cruise mode – the car with only an ICE uses the same mechanics – an engine to gearbox-to transmission- to differential/s to wheels….so the efficiency is not worse, but still probably better. How did you work it out to be worse I wonder ?

    >>>>>>>>>>>>>>>>>>>>
    (4.) The use of a four cycle engine. With an advanced power train controller (which the Volt has) there is no reason not to use a 2 cycle engine. The computer can make a 2 cycle as clean as a 4 cycle with 80% less moving parts.
    >>>>>>>>>>>>>>>>>>>>

    I suspect this is to do with noise and vibration. Most two-stroke engiens have to run at higher speeds to produce torque. Ultimately they are very powerful, but they don’t have the same capacity to produce the low down torque that a 4-stroke engine can. Electrical output from the generator is linked to the torque input at the shaft.

    >>>>>>>>>>>>>>>>>>
    (5.)The use of a battery pack to store energy instead of almost anything else. Chevy says the open road performance of the Volt is 50 mpg. Using that number as a basis for energy requirement, if we figure its 40 mile electric range that means that it takes .8 gallons of gas or about 5 lbs. As I mentioned the real world efficiency of batteries verses gas (15% loss for electric motors versus a 75% loss for gas engines) plus the joules per second of heat in gas versus the joules per second of the electricity means after calculation that li-on cells hold about 1/24 the energy of an equal weight of gasoline. 5 *24 = 120 lbs. Plus the weight of the motor.
    Using a small high efficiency gas engine as the auxiliary rather than a battery and electric motor saves weight, and can increase fuel mileage.
    >>>>>>>>>>>>>>>>>>>>>>>>>>>

    As I say, Toyota reckon that 85% of energy is lost in a car using just an ICE, not the 75% you claimed.
    Yes the batteries store much less energy than petrol does, but can you re-use petrol ? WHat happens when you brake in your regular car, you waste a huge ammount of energy just creating heat in the brakes in order to slow down. With an electric car you can regenerate that energy for use in acceleration later. There are other regeneration systems around, flywheels and hydraulics are succesful in this area, but they can’t also double up as the primary source of power too, So electricity is the sensible power choice.

    live in Scotland, only a small ammount of our electriccity is generated from coal, more from gas ( the cleanest fossil fuel), about 20% from hydro, 12% from wind, and some nuclear.

    I can also make 1kW of electricity as my heating runs just by using a CHP boiler, but it’s of no use if I have a petrol only car

    Chris Barron
    Scotland

    Comment by Chris | November 27, 2007 | Reply

  2. I am replying to a comment on my own page as its the most convenient method to address your concerns.
    (1.)As you said the Volt gets amazing mileage with its 2600lb chassis. Well for one thats not amazing. Its non-assisted mileage is 50 MPG. Thats awful. A diesel Volkswagen Jetta weighs 2853lbs and also gets 50 MPG. Without any exotic power train developments. 50 MPG is not a max for a fuel efficient 4.5 passenger sedan. Its a baseline. Fuel economy is a result of: power train efficiency, aerodynamics, rolling resistance of tires, and weight. If a heavier conventional car can get 50 it supports my theory that the Chevy Volt designers are going hybrid for fashion rather engineering reasons.
    (2.) A properly made manual transmission is 96-98% efficient. Ignoring the ICE (same in both) the losses of a generator turning a motor will be higher than the losses of a transmission. Further, differentials are necessary in electric powered vehicles, or the vehicle requires 1 motor for each wheel. Though this is done, 1 big motor with a 2% loss in the differential is will cost the vehicle less performance (and be far cheaper) than the weight of 2 motors of half the size. Direct linkage is ALWAYS more efficient. In fact, when transmitting power in a genset to motor arrangement, efficiency is reported as a function of steel shaft transmitting the power over the same distance that separates the the motor and genset.
    4. 2 cycles have less NVH than 4 cycles of the same power rating. Further 2 cycles make significantly MORE torque per rotation than 4 cycles. Most peoples concepts of 2 cycles are wrong because their experience with 2 cycles in tiny sizes. 2 cycle diesels (with pistons over 2 meters in diameters!) are among the most efficient ICEs on earth.
    5. Yes, energy cannot be stored in gasoline on board the car. Regen braking is great idea. However, regen braking AND a small ICE APU will yeild far higher economy than Regen braking. Further, regen braking is totally useless under 30 mph. The weight of the regen system costs more energy to accelerate up to 30 than it can even come close to recovering in de-acceleration (Regen braking is currently based on turning a generator or alternator. Below 30 mph and the velocity of the armature is to low to build up effective EMF strength)
    Finally, Toyota’s 15% figure is based off of the standard US vehicle fleet. This means lazy, detuned engines turning sloppy, automatic transmissions in bloated chassis on chubby tires. That is not a fair comparison of hybrid design to conventional design. One cannot compare a maximized design to un-maximized design. When the Chevy Volt is compared to cars like the Volkswagen Jetta (a maximized design) the hybrid is still better, but not nearly so much. Efficient engines turning efficient transaxles on quality chassis and good tires will beat the Chevy Volt.

    Does this make plug in hybrids a bad idea? No. PIH are logical, sensible, doable, and cleaver. My problem is the Chevy Volt, because GM is being so silly. The PIH represents a new EPOCH for the automotive industry. For a time, consumers will buy anything at any cost to be part of this event. Now is the time to introduce the 42V electric system, aluminum/stainless steel chassis, push rod suspension, 2 cycle compound turbo diesels, polycarb windows, roto-molded bodies, low rolling resistance tires, absorption rather than mechanical A/C, electric power steering, and slew of other technologies which both the environment and the auto industry needs, but the industry CANNOT introduce. The auto makers cannot produce what consumers will not buy, and consumers will not pay for new tech unless they know they need it. Right now represents a time that automakers can pretty much throw anything on a hybrid and 10,000 to 30,000 people a year will buy it. They throw this opportunity away on gewgaws like the Volt.

    Comment by oneliterofmight | November 27, 2007 | Reply


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