Electronic Design

What's All This Floobydust Stuff, Anyhow? (Part 9)

Well, it's getting close to the end of the year again, so this is a good time for another Floobydust column. In these columns I put some of the interesting tidbits, follow ups, and miscellaneous items that I gathered throughout the previous year.

Platinum-powered cars? Refer back to "Platinum (Chloride) Stuff," (electronic design, Dec. 6, 1999). Many people asked me if I wasn't doing "water injection." No, because the amount of liquid wasn't being depleted except to the extent of only a few grams per 1000 miles. They asked if I wasn't just leaning out the mixture. No, because the bubbles were just adding a couple ppm of air more than normal. So, this was insignificant.

After a year, my Beetle is still getting an 8% advantage from the Platinum Injection, and my friend is still getting 15% in his 1986 Dodge. Almost zero readers have said that they tried it. One guy claimed that he put this into a Falcon many years ago. This should have made at least a 10% improvement—but that guy said it did not.

The advantages of this Platinum Injection are confounded by the decision of the platinum people to increase the price by several dB. They obviously looked at consumers' rage about the cost of fuel and figured the price could be raised about from $99 to $177.

Still, I will recommend that this can provide a good ROI for any old carburetted car. I specifically DIS-recommend it for any modern fuel-injected, computerized car. It won't help there.

If you're going to buy this kit for $177 or whatever, be sure to calibrate your gas mileage carefully, on a standard route, at a standardized speed, etc., BEFORE you take out your credit card and buy the "platinum." Then, if it doesn't make a distinct improvement, send it back promptly within a month on the money-back warranty. If you drive a lot and burn more than two gallons per day, this will have a fairly good payback.

Hybrid cars: Most of the hybrid cars currently on sale significantly depend on gasoline, using a fairly large engine. I was proposing back in "What's All This Electric Car Stuff, Anyhow," (Electronic Design, Aug. 8, 1994, p. 107) to use a very small gasoline or diesel engine, perhaps 5 hp. That's just big enough for the car to limp along at 50 mph. Ideally, this car would be very clean for normal commuting—because for normal best-case commuting, I could make it from home to work without using any gasoline. I'd start with the batteries full and arrive at work with the battery charge fairly low. I'd charge it up from line power when I got to work, and also when I got home. Only in bad-case conditions would I have to start my gasoline engine, as a "reserve," to get home, or in case the battery got lower than normal, or for long trips.

But now, most hybrids seem to use the electric motor only in special cases, as a "boost" for upgrades or for acceleration, or for around-town stop-and-go driving. The gas engine is okay for cruising at highway speeds for long distances, but it isn't my preference for best economy while commuting.

What mode? Here's a related problem that nobody has addressed. Let's say that I'm driving a hybrid (gasoline-electric) car down a long hill. Do I want the car to be charging the battery? If the battery is low, should I turn off the engine, or keep it running to charge the battery? I do not necessarily know.

Let's consider the case where I get halfway down the hill and then decide to take a route that goes back UP the hill. In that case, using the downgrade's energy and the engine's energy to charge up the battery on the downgrade is wise, because I will soon use that energy to go up the hill.

But what if, halfway down the hill, I decide to take a route that continues down the hill? In that situation, charging the battery a lot isn't such a good idea because it may already be full, or it will soon be full.

Which route would I take? Heck, the car cannot know if I don't know, and I may not know until I see the traffic situation. I might not know until I arrive at the decision point. So I certainly can't demand that the car's computer must "do the right thing" in cases where I myself don't know where I will be going. I don't think any car can be "smart enough" to guess what I will want. A very wise car might ask me what "mode" I would like to run in, what strategy I would like to use. Should I keep the battery full? Or, should I let it run low? If I knew, I could tell the computer which strategy to use.

I must say, a lot of cars commute to Silicon Valley on old Route 17. There's a descent of 1000 ft. coming down to Los Gatos. Could you come down that hill and save a LOT of energy in a battery? I doubt if you could save up one third of that energy. So, it's not too efficient a deal.

Electric cars and hybrids do not just get good "mileage" because they regenerate lots of energy into the battery. They get good mileage because every aspect of the car is engineered for good efficiency—tires, weight, friction, transmissions, etc. If you had to commute over a big hill, I would be very skeptical that an electric car would be efficient or cost-effective. I suspect that they will be efficient mostly in flat country, and for some stop-and-go driving.

Flashlights: When we go to Nepal for my 35-day trek, we're only going to bring our two $20 PALight flashlights (www.lightechnology.com) with the white LEDs, and one spare 9-V battery. I don't plan to do much hiking at night. The moon will be full as soon as we get to Namche Bazaar, and when the moon is full again, it will be time to turn around and head for home.

I have gone window-shopping at www.glow-bug.com to see if there are any other good LED flashlights that I should try out. Un-fortunately, while this site tries to provide comprehensive information on a large number of LED flashlights, it seems to be a little deficient as it offers zero serious information for an engineer, or a backpacker—the power drain, expected battery life, flashlight weight, or light output.

The Web pages of the Action Light, www.hdssystems.com/ActionLight.htm, provide good engineering information on the design of the company's excellent product. But for $280, only people who have too much money, or are astronauts, or are Everest climbers, or are people who go on serious caving expeditions will buy them.

But then I realized that there were some annoying half-truths to the company's information on batteries. They recommend a lithium/sulfur-dioxide battery, SAFT L026SX, claiming that this puts out 7.5 Ah at an average of 2.8 V, or 21 Wh. A single alkaline D-cell weighs 5 ounces and can put out 15 Ah at 1.2 V (average), which is 18 Wh—not bad for $1. Yet the Web pages claim that their lithium can replace 2.5 alkalines of the same size. That's not so. They do have an advantage of almost two times in energy per weight, but also a 14: or 17:1 disadvantage in price per watt-hour.

I thought about this some more. Why do these guys recommend a nonrechargeable lithium battery for their flashlight system, when camcorders use rechargeable lithiums? Why don't these guys recommend a rechargeable battery?

I wouldn't go on a serious expedition with one type of rechargeable battery for my camcorders, and an incompatible nonrechargeable (or rechargeable) battery for my flashlights. (Each one is comparable in watts and watt-hours.)

HEY! I'm carrying three good old NiCads on my trek for my camcorder, and each is good for 2 Ah at 6+ V. Why don't I rig up some white LEDs with a current regulator for them? So I did. I specifically made the circuit "inefficient" so it would stop drawing current when the battery went down to 6 V—and not over-discharge the battery. I used the basic current-regulating circuit from "Current Limiter Stuff" (Electronic Design, Sept. 5, 2000).

But I only put the LEDs in series with the power-supply lead, not in series with the pnp's collector. I put in five LEDs in parallel, each running at about 20 mA, with a little 12- sharing resistor for every LED, and a 0.66- resistor in the SENSE path of the LM334. Now I can read a book or go to the latrine at midnight and never use any nonrechargeable battery. Or if the sunlight has been in short supply and my NiCads are low, I will refuse to use them. It's good to have compatible battery systems, and this light is quite bright!

A friend pointed out that white LEDs can put out 15 to 18 lumens per watt at their high output level of 20 mA per LED. That's just about the same as the efficiency of a 100-W bulb (1690 lumens per 100 W). Now, halogen bulbs can put out twice the light output as conventional incandescents, at large power outputs. But halogens and all incandescents are much less efficient (less lumens per watt) at smaller output levels, because the filament's heat losses are relatively poor. Halogens can't be throttled back by just going to low voltage or low power—but LEDs become more efficient at low currents. So the day of the white LED isn't just coming—it's here. If you need a good long-life flashlight, I think you'll like these white-LED flashlights.

BABES with AXES? All of you folks who enjoyed the music of "Babes With Axes," that I mentioned in "Obsession Stuff" (electronic design, June 8, 1998) will like the CDs Corduroy by Laura Kemp and Ghosts Of Dreams by T.R. Kelley. These women are two of the "Babes." (The cost is about $16 each. Send your check to Debbie Diedrich, P.O. Box 12178, Eugene, OR 97440.) I'm slow to catch on, but there's some great music in there.

Fascia boards: Many people wrote in to remind me that the vertical board "F" in my Sketch 2 for "Sudden Cessation of Stupidity" (electronic design, Aug. 7, 2000) is called a "fascia board," and if that board weren't extended lower than the adjacent horizontal boards (soffit covers), then of course I would have trouble with water running over to the house. I had to reply that my sketch was a little sloppy, and the fascia board really did extend down a little (0.25 to 0.5 in.) below the soffit boards. But that isn't enough! So I will be adding quarter-round strips at the bottom of the fascia boards too for a double-barreled defense and stop water from running uphill!

More Fuzz? I was ambling through a pharmacy and checked out the blood-pressure instruments sitting on the shelf. Some were $39.95, while others were $99.95, as you would expect. I suddenly noticed the name OMRON—people who have long promoted Fuzzy Logic. Did this top-of-the-line one have FL? I picked up the box. Did it brag of its use of FL? NO! This one had "Intellisense." I laughed—now Fuzzy Logic cannot be confused with Hairy Logic or Furry Logic. It seems that when it's a consumer product, they're calling it "Intellisense." More grist for the Floobydust mill....

All for now. / Comments invited!
RAP / Robert A. Pease / Engineer
[email protected]:

Mail Stop D2597A
National Semiconductor
P.O. Box 58090
Santa Clara, CA 95052-8090

References:

  1. Pease, Robert A. "What's All This Fuzzy Logic Stuff, Anyhow?" Electronic Design, May 13, 1993, p. 77.
  2. Pease, Robert A. "What's All This Fuzzy Logic Stuff, Anyhow? (Part II)," Electronic Design, Nov. 1, 1993, p. 95.
  3. Pease, Robert A. "What's All This Fuzzy Logic Stuff, Anyhow? (Part III)," Electronic Design, Nov. 11, 1993, p. 105.
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