Kirt's Cogitations™ #224
RF Technology in Autos
RF Technology in Autos
There are few things more compelling for considering the purchase of a new car
than being far from home in your old beater, and having the engine shake and rattle
so violently that people on the roadside stare at you as you drive by. The wisest
of them would have been contemplating taking cover lest a part fly off. I knew the
time for such a catastrophe was nigh, but the hope was that the beast (my 1995 Mercury
Tracer) could be pacified for just a while longer. Alas, with no compression in
cylinder #2, its days are over, and now I have to decide what will replace it. The
model choices are nearly overwhelming, as are the mechanical and electronic options
(RF and otherwise) available for them.
This will be my first new vehicle
in more than 25 years.
I am no tree-hugger, but do consider myself to be
an environmentally responsible person, so good gas mileage will be a prime consideration
(≥ 30 mpg/48 kmpg). The Tracer – or Trasher as I affectionately refer(ed) to it
– managed about 26 mpg traveling to and from work, with a 1.9 L engine and an automatic
transmission. Based on some preliminary research, it appears that gas mileage is
generally really lousy on most vehicles, so that reduces the options considerably.
It is dismaying to see that in the year 2007 most vehicles are not getting at
least 30 mpg. Emission control and additional safety structures/device devices are
responsible for about a 10-15% reduction in mileage according to my research, but
come on, with all the computer feedback and engine/transmission technology available,
25 mpg for a mid-size sedan is ridiculous. Even the hybrids barely eek out 40 mpg.
The 1996 Mazda Protégé I had (before somebody ran a stop sign and totaled it) was
getting 40 mpg. Has power train technology and vehicle aerodynamics stood still
for a decade?
Speaking of hybrids, I would really like to buy one, but when
considering the real cost of ownership over the long run and realizing that for
most situations there is very little advantage from a gas mileage perspective of
operating one, the additional expense cannot be justified. Many articles that approach
the evaluation in an intellectually honest way point out the necessity for replacing
the battery banks after about five years and the ecological impact of disposing
of the old batteries in a landfill. The financial cost is on the order of a few
thousand dollars, and the eco cost is a lot of hazardous, heavy metals in a reclamation
depot. Most, if not all, of the lead-acid batteries get shipped to “developing”
countries to be processed by workers who are lucky to be provided with rubber gloves
and an exhaust fan.
Some hybrids use NiMH (nickel metal hydride) cells, but
they are also full of heavy metals and are even more expensive to replace. Research
is under way for the use of lithium technology batteries which are more environmentally
friendly, but need to be made less prone to explosion (I have linked to many fire-in-the-pants
cellphone news stories over the years). As with plasma displays and HDTV, I will
let the wealthier amongst us finance the technology development and cost-reduction
before buying one myself. However, I will be the biggest fan (which is actually
a short form of “fanatic”) and enthusiastic promoter of those who perform and underwrite
the financial cost of development.
On to the real topic of this article:
RF technology in automotive products. The science has progressed far beyond having
your iPod broadcast over the FM band so your $2k, eardrum-popping, 500 W stereo
system can blast it through a dazzling array of crossover-networked speakers. Hands-free
(Bluetooth) cellphone interfaces are mere 20th century technology, as are keyless
entry systems and radar detectors. Throughway SpeedPasses for toll booths have been
around since the early days of RFID. OnStar™ emergency reporting systems debuted
in the 1990s and satellite radio in the late 1980s. That was then; this is now.
One of the most impressive developments (IMHO) is the object detection system
that uses radar, sonar, or a combination thereof to gauge the distance to nearby
structures or items to help prevent bumping into the side of a building or running
over a tricycle or most importantly, running over a living being. These systems
have been adapted to assist in tasks like parking where curb distance measurements
are displayed to the driver, and in parallel parking. Taking the science to an extreme,
BMW and Lexus are now running commercials for a car that will parallel park itself
or back into a parking space with no help from the driver.
systems (CAS) employ radar to survey the area surrounding a moving vehicle and search
for potential hazards like a car moving into your lane with too little clearance,
and vehicle making a sudden stop ahead of you, or a truck calculated to be on a
collision course with you. An appropriately urgent warning is generated for the
driver, and in some cases the CAS will take evasive action independent of the driver
(such as applying the brakes). Both the CAS and the aforementioned automated parking
systems will take a lot of faith on the part of the driver to allow an inanimate
object to basically commandeer the vehicle while in motion.
extreme, but impressive nevertheless, are gadgets like the tire pressure monitoring
system (TPMS) which consists of a MEMS based silicon sensor and RF transmitter inside
each tire (sometimes in the valve stem) that sends real-time data to a receiver
for inclusion in the vehicle health status report. There are also efforts underway
to replace all of the control wiring for electrical systems in the rear portions
of the car with Bluetooth-like communications that will allow only a single high
current bus wire to be distributed to items such as the tail running, brake, and
backup lights, and allowing the local wireless controls to do the switching. Doing
so saves weight and simplifies the wiring harness.
All of the advancements
have come about due to the brilliance of the people who have pioneered MEMS devices
and the miniaturization and integration of entire complex RF systems onto a single
piece of silicon or GaAs. Of course, a lot of credit goes to the manufacturing engineers
who have figured out how to produce the products in high volumes and at an affordable
price. Such feats are inspiring to the next generation of engineers and scientists
who will take it upon themselves to push the boundaries even farther. Finally, some
of the whiz-bang technology that was promised us for the 1990s, by magazines like
Popular Science and Mechanix Illustrated, are coming to fruition.
except for the 100 mpg cars.