Archive for November, 2009

A Battery of Questions

November 24th, 2009 Comments off

cell photoI often think I know more about things than I really do. And one thing I think I know a lot about is batteries – the kind that goes in your Prius, and the kind that will go in your Volt.  As most car-folks know, the battery industry is currently transitioning from nickel-metal-hydride (NiMH) batteries (i.e., what’s in your Prius) to lithium-ion (Li-ion; i.e., what’s in your Volt.  Or Leaf.  Or Tesla.).  And, it turns out, a battery isn’t just a battery – different types of batteries require significantly different control mechanisms to manage how much and how quickly they are charged and discharged, and how they behave while in operation, so that lifetime, safety, and performance are maximized.

But it’s even more complicated than that.  There are dozens of different Li-ion battery chemistries.  Every battery manufacturer has their own idea of the right combination of chemistry and manufacturing process that will result in the winning formula.  But each of these batteries has very unique characteristics that require very specific controls once it’s embedded in an automobile.  Auto manufacturers, on the other hand, would like to be chemistry-agnostic.  (They just want a battery that meets their requirements.)  But, given that the battery dictates the control software, it’s not so easy for a car maker to just pick a battery off the shelf.  Substantial development effort must take place between the auto maker and the battery maker, so that the car and the battery work together as a system.  (Just look at all the effort that has gone into the Volt’s development, in conjunction with Compact Power / LG Chem.)  Once a vehicle has been developed with a particular battery in place, changing battery suppliers would be a major hurdle.  As a result, there have been a lot of joint-ventures formed between auto manufacturers and battery companies, effectively tying their efforts together.

In the end, we’ll likely see each electrified automobile maker tied to one particular type of battery.  But there’s also the issue of standardization in the industry.  I wonder, if each auto/battery manufacturer takes a different path, will this complicate standardization?  How will this effect business models like Better Place – will their entire infrastructure be wedded to one type of battery and one manufacturer?

Eco-Tires Revisited

November 12th, 2009 Comments off

Bridgestone EcopiaA few months ago, I wrote about eco-friendly tires, and postulated that the decrease in rolling resistance of such tires may result in slightly less grip.  Well, that was a case of a little knowledge being dangerous.  Reading an article this month (in Automotive Engineering International, of course) about Bridgestone‘s new Ecopia line of tires, it was explained that the decreased rolling resistance comes from a sidewall design that “offers improved carbon dispersion.”  In other words, the sides of the tire are stiffer, and flex less as the tire rotates on the road under the weight of the vehicle.  (Yes, it takes energy to bend the tire sidewall – a stiffer sidewall = less bend, and more energy transferred to the road.)  I surmised incorrectly that grip must suffer.  I was wrong.

But now I have to ask:  Why is this technology reserved only for the ECO tires? Stiffer sidewalls are a good thing from a performance standpoint – that’s one reason higher performance tires typically come in lower profiles.  (It allows the suspension to more precisely do the job for which it was designed.)  Is there any downside to making tires of all performance categories more efficient?

…Of course, until people learn to keep their tire-pressures properly inflated, it’s probably a moot point…

Categories: Tires Tags:


November 11th, 2009 Comments off

I hate plastic.  Mostly because it, mysteriously, doesn’t dry in the dishwasher.  But also because a lot of things that used to be made with more durable materials (and that are now made with plastic) don’t last very long.

On the other hand, plastics have been beneficial in many respects, especially in the auto industry.  I remember people complaining a few decades ago when polyurethane and polypropylene fascias replaced the large chrome bumpers that were on most cars, but the truth is the use of these plastics allowed for better aerodynamics, sleeker designs, and even improved safety.

ZF Carbon Fiber Reinforced Polymer Strut

ZF Carbon Fiber Reinforced Polymer Strut

ZF Transverse Leaf Spring Axle

ZF Transverse Leaf Spring Axle

The latest issue of Automotive Engineering International describes how plastics are taking the next step in automotive design: being incorporated into suspension components and other structural areas of the car.  For example, ZF is developing a transverse-leaf-spring rear axle utilizing glass-reinforced plastic for the spring itself, as well an upside-down carbon fiber-reinforced polymer strut and plastic spring for the front suspension.  In addition to the benefits of lighter weight (and lighter unsprung weight, which magnifies the handling benefit) the strut can be manufactured with an integrated signal fiber that acts as a strain gauge, providing a warning of any impending structural failure.  (This is not to suggest the chance of a structural failure with these components is any greater than with traditional steel suspension parts.  Formula 1 and Le Mans Prototype race cars have been using composite suspension components for years.  And in fact, these  components may actually be safer, since they won’t rust when exposed to road salt and water, and they can actually let you know when there’s a problem!)

Additionally Bayer MaterialScience is developing polycarbonate windows for use in road-going vehicles.  This again is a case where technology that has long been used in motorsports is making its way to the masses.  The problem with polycarbonate windows has historically been the ease with which they scratch.  That’s not a big deal in racing, where the windshield gets replaced frequently.  But Bayer has developed coatings which make polycarbonate windows stand up to the rigors of life on our nation’s highways.  Here, too, we have the benefits of reduced weight (especially up high in the vehicle, where it affects handling) and increased safety (no shattered glass).

The use of plastics and composites will play a significant role in the design and manufacture of lighter, more fuel-efficient vehicles. (What’s next, plastic engines?!)  …Given how far we’ve come with plastics, it seems that by now someone would have made a plastic child’s sippy-cup that would emerge dry from the dishwasher…

Technical Minutiae

November 9th, 2009 Comments off

When it comes to cars, I’m fascinated with technical minutiae.

In the tech Q&A section of one of the car magazines I read, the question was recently posed, “Are there any disadvantages to direct-injected engines?”  Many automakers are switching from port-injection to direct-injection in an effort to increase performance and fuel-efficiency.  (What’s the difference?  In traditional port-injected engines, fuel is squirted into the incoming stream of air before it goes past the intake valve into the combustion chamber where it is ignited.  Direct-injection, on the other hand, involves injecting the fuel directly into the combustion chamber – and air is the only thing that enters via the intake port.)  Direct-injection is used in many high-end and mainstream vehicles now, and will probably make its way further down-market very soon.

MicroscopeTurns out, there are a couple of concerns with direct-injection that aren’t immediately obvious.  One involves the intake valve itself.  Along with the air that flows past it is the small amount of gases that leak past the piston-rings and into the crankcase, returned into the intake stream via the PCV (positive crankcase ventilation) valve. This is essentially the “oily” air that resides in the bottom half of the engine.  Over time, the PCV system could cause oil-residue to build up on the back-side of the intake valve.  In an older port-injected engine, the gasoline washes this residue away, but in a direct-injected engine, this residue never gets cleaned off.  (Ford solved this problem by adding an additional filter to the PCV system.)  Another concern is that directly injecting gasoline into the cylinder could wash the oil-film from the cylinder walls, increasing wear of the rings.  My guess is that this will turn out to be a non-issue, given the amount of testing that goes into proving the fundamental combustion processes of engine technology.  But this is what I find fascinating – there are significant repercussions to even slight design modifications.

It’s sort of the law of unintended consequences.  (Increased ethanol production caused a spike in the price of tortillas, anyone?)  Not long ago, I had a conversation with an automotive engineer that was studying the role that lubricants (i.e., your motor oil) play in auto emissions – a role that is increasing as vehicles become more fuel-efficient.  Motor oil formulations have been (and will continue to be) altered in order to reduce their contribution to tailpipe emissions.  As an example, the amount of zinc dialkyl-dithio-phosphate (ZDDP) was recently reduced in engine oils, due to its detrimental effects on emissions equipment (such as catalytic converters) over time.  Unfortunately, it’s the ZDDP that helped to protect the metal-to-metal impact surfaces in engine valve-trains up until the 1990s.  Owners of cars built before then are now experiencing increased camshaft and lifter wear, upsetting a lot of folks who drive classic (and near-classic) cars. …A slight change somewhere results in unforeseen consequences somewhere else…

At this point, if you’re still reading, your eyes have probably glazed over.  Technical minutiae isn’t for everyone.  But sometimes, it’s the tiniest of details that matter.

Teaching By Example

November 4th, 2009 Comments off

I have a 5-year-old son.  He’ll be six in a couple of weeks.  Recently, he told me, “Daddy, when I grow up, I want to make fast cars, but ones that don’t have exhaust pipes, so they don’t hurt the earth.” …Talk about a proud father moment… Now, I’d like to take credit for his coming up with this thought.  And, for the most part, I probably can.  I’ve spent the past 2 years focused on exactly what he’s talking about, a fact which has impacted his life as much as it has mine.  (On the other hand, he’s spent every day of his life – until recently – knowing that daddy has a race car in the garage, and that he tows it with an enormous pick-up truck.  …I’m glad he chose to focus on the positive.)  Plus, he does go to a school where being aware of the natural world is a big part of the curriculum.

But this got me thinking: there are currently over a quarter of a BILLION motor vehicles registered in the U.S. (and about a BILLION worldwide).  And if we keep the status quo, those numbers could double in the coming decades, with disastrous results for our environment, the climate, national security, the economy, and our standard of living.  Now, most in the auto industry have finally acknowledged that combustion exhaust is bad.  (And to the climate-change skeptics that remain, I ask, “My kindergartener gets it, so why can’t you?“)   And more and more folks are working on ways to transform transportation in a broader sense, and not just clean up our cars.  But we’re just getting started.  If things are going to change, it’s the kids of today who are really going to have to effect it.  If they grow up with the mindset that, “my parents drive a big SUV, so I will too one day,” then stagnation occurs.  On the other hand, if they are taught early on that the way things are isn’t the way things have to be, then change becomes all the more possible.

I can’t wait to see what our cars will look like 20 years from now.  And I can’t wait to find out if they’ll still be our primary mode of conveyance, or if we’ll just use them sparingly, for fun.  (I’d much prefer to take public transit during the week, and drive a Porsche on the weekends…)  But mostly, I can’t wait to see if my son might actually follow through on his fleeting yet poignant declaration.  ...And if the cars are fast, like he plans, then that WILL be a proud father moment indeed!

Toy Cars

Categories: Climate Change Tags: