Fighting for Efficiency

It looks like the weakest link is the gas engine. How far can you go on a fully charged set of batteries? (And what's the lifetime of the batteries before replacement is needed?)

Yes, definitely the engine.

Actually I was just using the Pod One as illustrative of cumulative efficiencies in general -- and a lot of processes have many steps and energy conversions. One day I was playing around with the calculator, thinking "well, what happens if you relax standards a bit on efficiency?"

Of course 10 steps is quite a few, but the numbers are striking. Without thinking about it too much, gut feel might have told me that I'd get 2% or 5% efficiency if each step is 50% efficient. .00097 (.097%) is mighty low.

The plan is to be able to go 30 miles before the engine starts up. So, for a lot of people, it would be effectively an electric-only vehicle (but they wouldn't drive around panicked, worrying that they will be stranded). Shorter range on elec alone, actually makes the basic efficiency of the vehicle a little better (because you are carrying around less battery weight) but also makes it more likely that the engine will start up. I think with advanced SLA, we could get three years. They recycle well, and are cheap. With other batteries, the initial cost skyrockets, but they last much longer. We'll probably end up offering options.

Of course, if the EEstor pans out, then we ditch the engine entirely. Just plug in and go.

My daily commute - to work, home for lunch and back to work is 16 miles - so that would be great for me. How does it handle a side impact from a Texas sized F350?

How does it handle a side impact from a Texas sized F350?

Loves it! Actually, funny you should ask. I think that is a major hurdle for small vehicles. I filed a provisional patent on a side impact protection system, which provides 18-20" of crush space before the F350 hits the side door beams. This is possible with tandem seating , but would make a too-wide and very odd-looking vehicle if added on to a typical small car. (On mine it provides an FI or GTP look)

All traditional cars have zero side impact crush distance. On my vehicle, this system fits behind the front wheels, forming an extension of the fenders (not shown in my avatar pic). Front and rear impacts are easier to handle by making the crush distance large, which has a generally beneficial affect on aerodynamics, and a not too detrimental effect on overall weight.

Even though little cars can easily do well in front impact tests (because they are tested against their own mass), they need greater crush distance all around to deal with impacts with vehicles of greater mass -- which in my case means almost everything on the road.

I think Toyota received some bad press recently for poor side impact protection on its Yaris -- I haven't had a chance to dig up the articles.

Check your math 1 KW @ 50¹⁰% = 97 watts...... you lost 2 decimals points with the percent sign.

.5¹⁰ = 0.0009765625

0.0009765625 x 1000 watts = 0.9765625 watts

(50% = .5)

Sorry % ^&*@ #$$^% $ micro$o$t software.

I like your upgrade.. pic above

Seems to me that if you wanted to improve efficiency, it would also be better to simplify and have less links in the chain or put them in either/or configuration

Seems to me that if you wanted to improve efficiency, it would also be better to simplify and have less links in the chain or put them in either/or configuration

Definitely.

The whole hybrid idea starts out looking absolutely nutty: run an inefficient engine to charge a battery to run a motor to drive the wheels (through a transmission). It all works only because ICEs go from inefficient at full load and optimum rpm to positively-absolutely-incredibly-abysmal* at light loads (where they ordinarily spend most of their time in car usage).

Serial hybrids tend to have much smaller engines than parallel hybrids, and can spend virtually all their time fully loaded (or be shut off entirely). But (as you say) an either/or config is really attractive when you are simply cruising along at a speed requiring the optimal loading of the engine (on my vehicle that speed is about 70 mph). At that speed, you'd want to throw away the weight, cost, and inefficiency of the intervening components. Providing a direct drive mode helps.

Industrial processes where air motors are used are incredibly lossy. Fortunately most people are aware of this, but many industries are slow to change -- and there are loads of plants where, when machines stop overnight, or for a break, the hiss of air leaks is deafening. There are loads of applications where linear actuators would work better than cylinders -- but of course they cost more.

* 10%, 5%, (at the flywheel -- not even the wheels)... even 0% when idling.

Another problem is the auto world's obsession with power, gearing and the minimum RPM to keep a IC engine running.

If you compare a bicycle to a IC engine there is a huge difference in efficiency. A bicycle is powered by a 1/4 to 1/3 hp engine, and is capable of attaining fairly good speeds. The typical car has around 200 hp but has the efficiency of ~ 1/500 that of a bicycle.

compare the main differences;

1. Gear ratio of bicycle in high gear would typically travel 28 feet with one complete turn of the pedals

from Wiki http://en.wikipedia.org/wiki/Gear_ratio

A single engine revolution travels just over 3 feet in 6th gear and as little as 8 inches in first gear

Obviously we need less gears, used in a wider range to provide better efficiency

2. Weight; -nothing like stating the obvious - less weight uses requires less energy.

3. When stopped a bicycle does not use energy. An IC motor typically must keep turning between 500 to 750 rpm. Think how stupid a biker would look if he had to keep pedaling when he wasn't moving. Yet we do this with IC engines all the time.

Unlike the power hungry auto industry trends, we need to reduce minimum engine rpm and widen its range of operation and be able efficiently stop and start the engine. This includes cold running engines.

On an average rush hour day (assuming she could get past the traffic) my wife could make it to her job in about 1/2 the time on a bicycle... and she'd feel better and live longer* too boot.

*Assuming she didn't get whacked by a car.

Obviously we need less gears, used in a wider range to provide better efficiency.

Actually we need more gears or a continuiously variable arrangement, to keep the motor turning in the range of highest out put [torque, horsepower] to allow the use of the smallest most efficient powerplant possible!

An IC motor typically must keep turning between 500 to 750 rpm. Think how stupid a biker would look if he had to keep pedaling when he wasn't moving. Yet we do this with IC engines all the time.

A typical 4 cylinder motor idles @ 1500rpm or more

Hybreds use a high speed starter [1000-2000rmp] to eliminate the need to idle needlessly. Low speed starters, necessitate very rich mixtures, lowering efficentcy & increasing emissions.

A typical 4 cylinder motor idles @ 1500rpm or more

According to the reliable web source below, idle speed of a Jetta is anywhere from 7,000 - 9,000.

http://autorepair.about.com/library/faqs/bl082e.htm

Actually 700 - 800 is typical for 4 cyl, manual transmission, out of gear. Larger engines (especially V8's) are lower. At 1500 rpm, my Honda Accord does 45 mph in 5th gear, but with light load will cruise along perfectly smoothly at 30 mph (1000 rpm) in 5th.

I like the constantly variable which has wider range and less gears. Less gears = less weight

The problem is that we never use all the horsepower. The extra weight to create that horsepower is dead weight that must always be carried around. It is like having a two seater bike with only one person pedalling. Do we really need 200hp to transport 1 to 3 people around?

Maybe Ken will tell us if this can be done with maybe 40hp & have an accecptable 20-60 time [gotta be able to get on the freeway safely].

I have a 06 toyota idles around 1200rpm [emissions], has 100hp totally accecptable roll on 20-65 proformance, seats 4 adults. Would probably die a horrible death in a side impact w/a f-350. Gets an honest 30mpg, bout $5k less than a hybred.

On CVT's the best example is a snowmobile. Totally analog just springs & weights, to determine the rate of acceleration. Unfortunatly there are substantial frictional losses. Subaru made on road version using a metal belt, always problematic quality wise. A torque converter is a CVT, except the extra rpm's are turned to heat.

Hi Blink,

Again, congratulations for your struggle for a better world.

Your question became paramount nowadays. Every bit of efficiency counts. When working on such bits, it is said you make incremental improvements. When working at one or two orders of magnitude higher, it is said you make a disruptive technology.

Your arithmetic example says a lot. I would go not only for incremental increase of each component's efficiency but also for decreasing the number of them! Minimizing the number of energy conversions and components leads to dramatic improvement of the overall efficiency. In your example, cutting just 2 components means to get 43% overall efficiency instead of 35%. This could be significant.

Another thing is to pay attention at matching impedances between sequential links of the chain. The maximum transfer of energy from one link to another happens only when the downstream link output impedance equals the input impedance of the upstream link. In some cases, it is called resonance. It is well known that the concept of impedance is applicable not only at electrical/electronic circuits but at mechanical, hydraulic and thermal systems as well. Unmatched impedances lead to reflection (return) of some of the energy flow to the source. This is a waste and sometimes could be a hazard.

Another problem is when one form of energy is converted into more than one form of energy. This leads to lateral flows of energy in a serial desired flow. Again, those are usually wasted energy.

I hope this helped the discussion.

I hope this helped the discussion.

Indeed! Actually your response is the kind of thing I had in mind as likely responses -- i.e., less about the specifics of a hybrid vehicle, but more about the value of reducing the number of energy transfers, number of components, and vigilence in keeping the efficiency of everything high -- no matter what the process.

The math was really striking to me. Obviously, we know about exponential this and that, and know that even good efficiency (90%) taken through enough steps means a lot of losses. But 50% is GREAT (unattainable) efficiency for an ICE. Then, take that number through 10 steps... and you might as well say that you have no efficiency at all -- all you have is losses. You hit the "=" button... see .000something... and think whoops, I must have done something wrong.

Dig a well to get oil and refine it. Meanwhile, drive to the farm supply to get corn seed and diesel for the tractor... til the soils... plant the corn... harvest... transport the corn to the ethanol plant... grind the corn... heat the slurry...

... eventually it shows up as E85 in Ken's Wild Ride...

... and it's all downhill from there!