Logistics

July 1, 1993

Logistics

By M.L. Simon

Why can’t we have the fuel-efficient cars we see and hear about in magazines and on television filling the auto company’s showrooms in the next model year? Why don’t we already have them this year? There is a reason. It is a one-word reason. That word is logistics.

I’d like to discuss here the difference between a prototype built by a school or an auto company and a production auto that you can buy off the showroom floor.

I’m going to start out with the very simplest of the new technologies, the Integrated Starter Alternator (ISA). This is a starter motor that is also the alternator (electrical generator) of the car. If this device were made part of the engine, we would get a number of valuable improvements. First, it would be a more efficient electrical generator than the current separate alternator for two reasons. One is that losses from the rubber belts needed to transmit force from the engine to the alternator would be eliminated. Second is that because the ISA would have a larger diameter, its magnetic structure could be much more efficient than the structure of current belt-driven alternators. There is a third advantage to a more efficient magnetic structure. In the starter mode, the starter motor becomes more powerful and more efficient. Coupled with a higher battery voltage (36 volts nominal, about 42 volts while the engine is running), an engin- on-demand system becomes viable. That means that when the car is stopped at a stop light, the engine can be turned off to save fuel. A fourth advantage of an ISA system with a larger battery is that instead of engine braking where the engine absorbs some of the energy needed to slow an auto, the generator/battery system can absorb some of that energy, returning it to the motor on the next start-up cycle. In effect, the energy needed to start the engine in stop-and-go driving is energy that would be otherwise wasted in heating the brakes.

This is a lot of payback from what seems like a simple design change—a change that has already seen prototypes on the road. After all, once the design is proved, what prevents the car companies from going from a proven design to a million vehicles on the road? Well, we are back to that word: logistics.

A good place to start is batteries. Twelve-volt batteries are easy to find. Twelve-volt lamps are manufactured in the billions. Twelve-volt accessories like radios and heater fans are commonplace. Where do you get 36/42-volt equipment? The answer is that right now you don’t get it anywhere. So the answer is that you probably need a 42-volt to 12-volt converter and an auxiliary 12-volt battery. Thirty-six volt batteries?

Fuggedaboutit. In the initial production models, they will likely be made from three 12-volt batteries strung together. The battery design will have to be different from the current design. A battery called on to make five or 10 starts a day is very different from one that can reliably

deliver 500 or 1,000 starts a day. So the car companies must go to the battery companies with a specification and ask them to design a battery that will fit in a currently produced 12-volt case that will do the job.

The battery company then asks their battery engineers to take a whack. They come back with a design after a few months of effort. Then the prototype shop comes back with a few copies after a few months more of effort and some back and forth with the engineers. Now the real fun begins. The battery must be cycle tested, charged and discharged 1,000 times a day to simulate operation in the new vehicle design. There are problems. There are always problems. So the engineers come up with a new set of compromises (otherwise referred to as the revised design), and the testing begins again. So the months tick by. Finally, the design works acceptably at the normal temperature range. However, cars do not work in a normal temperature range. They must work reliably from a 40-below Arctic environment to a 120-above summer desert environment. More testing. More redesign. More compromises. After one and one-half to two and one-half years, the battery company finally has a pre-production prototype lot of a few hundred batteries to deliver to the car companies.

Now the serious fun begins. All the suppliers to the car company have been going through a similar drill to get their parts ready for the preproduction prototypes. The parts are all there, and they are then hand assembled into a few hundred pre-production prototype vehicles. Any

problems in assembly are noted for further revisions in the delivered parts. Now it gets interesting. The vehicles are first test driven on the auto company’s proving ground tracks to shake out the bugs in the hardware

and software. Did I mention software? Most of the functions of a vehicle with an ISA system are controlled by software. So now, not only do the parts have to work as specified, but they also have to work in the way the software commands. If not, either the parts or the software must be modified.

Finally, everything passes the track test, and the pre-production prototypes are parceled out to the auto company executives and their families for a year of test driving in all weather conditions. Plus, a few are parcelled out to writers in the field to test drive and give their opinion. This process takes another year. All the while, known modifications are being made, and possible needed changes are being anticipated from the early driving reports. If all goes well, three to six months after the year of test driving is done, the new component designs are ready for production. Home free? Not by a long shot.

Now the factory designers must come in and design a factory to produce the newly designed and proven components. Orders must be placed for the special tooling required. Orders for plastic cases and plastic grid separators go out. Orders for lead of a certain chemical composition and thickness. Orders for lead oxide paste. Orders for tank cars of sulfuric acid. Even orders for new software to track the manufacturing process. Orders for machines. Orders for punches and dies. Orders for bins to recycle the scrap produced by the production process. Orders. Orders. Orders.

Now, of course, you would like to compress this schedule where possible. It costs money to keep all these testing facilities, engineers, technicians and designers on a project. So it would be good if while final testing was going on, the design of the factory were started. This, however, entails risk. What if, due to testing, it is found that the final design needs to be radically altered? What if the factory design and the tooling ordered for it needs to be scrapped? Suppose a light went on in some really bright engineer’s head, and he found that with a different factory design, he could shave $10 million off the production of a million batteries for 350,000 cars and reduce the scrap produced by one-half million pounds; or, because of a serious design flaw, it were found that all the batteries built according to the original factory design would be scrap after six months on the road. To accomplish this change, though, the battery company needs to adjust its factory design, take a three-month schedule slip and order $2 million of new tooling. Ouch.

What I have presented is just one component of a radically new car design, a component whose engineering parameters are reasonably well known from more than 100 years of manufacturing experience. I haven’t even begun to cover the power electronics required to make all this a going proposition. We don’t have 100 years or more of experience with multi-kilowatt power electronics on mass-produced vehicles. What we have is roughly zero years of experience. This is not a trivial problem.

So the car companies have fixed all the problems that they found in their 100-vehicle pre-production run. Now what happens when they have a problem that shows up in one out of every 300 vehicles after two years on the road, and they have made a million due to strong demand? Disaster. They now have 3,000-odd dissatisfied customers and a million vehicles to recall. They get bad word of mouth and a very large bill for the recall. It is not easy for an auto company to put a brand-new design into the field. The risks are huge, which is why the changes will not come all at once, except in research and development vehicles. So when your favorite greenie asks why we can’t have in the showroom tomorrow the vehicle he read about in a magazine yesterday, you can give him or her the one-word answer—logistics.

The good news is that such American-made vehicles will be available in September 2003, the 2004 model year. Happy driving.

M. L. Simon is an industrial controls engineer for Space-Time Productions and a Free Market Green (c) M. Simon – All rights reserved. Permission granted for one time use in a single periodical publication. Permission also granted for concurrent publication on the periodical’s Web site.

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