Bzzt-Crackle-Pfft! (long)

[Mike Arman <armanmik@n-jcenter.com>]

Reading the March issue of Automotive News (dealer publication), there's a
fairly detailed article about the coming thing in automotive electrical
systems - always a point of interest for us Audistas.

Since 1996, 27 auto makers have been paying MIT $50,000 each, every year,
to be a member of an auto-electric consultation and "steering committee".
The subject is creation of standards for the next major auto electric
upgrade, due at first in 2001-2002 in either BMW or Mercedes, and then by
2005 in everything else. (And since Audi also builds German luxo-sedans,
they won't be far behind . . . )

42 volts.

Problem was foretold by our very own type 44 TQs - not enough electrical
capacity. Modern luxury cars use as much as 2,800 watts (at 14 volts,
that's 200 amps), and that requirement is expected to double in the next
five years. All this power takes lots of copper to move it around: The
wiring harness in a new Buick is stated to weigh 75 pounds!

12 volts has been around since the 1950's, and automakers feel there are
enough compelling advantages to go to 42 volts "real soon now".

Some of the systems contemplated are electromagnetic steering and brakes
(Yeah, I'm really going to trust those!), electrically heated catalytic
converters, and solenoid operated engine valves (!) which are currently
being developed and tested by a company in California - each valve takes
almost 100 watts at 6,000 rpm, times at least eight valves, and you can see
the power required. (We already have something similar: EFI valves,
computer controlled timing and duration). This allows engine makers to
dispense with camshafts, drive belts, lifters, rocker arms, etc, and allows
direct computer control of the timing and duration of the valves - want a
hot cam, just change the code in the EPROM!! - a trick WE are well familiar
with. This would allow continuously variable "cam timing", and lift - no
more complex, expensive mechanical systems. (Just complex, expensive
electronic systems.)

(Let us pray that Microsoft doesn't write the code - then the joke about
rebooting your car may become REAL!!!!)

Problems to be overcome include distribution and reduction of voltages
throughout the vehicle to components that still use 14 volts - this may
require double systems - a 14 volt and a 42 volt system in the same cars,
at least until the 42 volt stuff has completely supplanted the 14 volt
stuff. There's also a problem with consumer acceptance: People won't pay
more unless they see a perceived benefit, and this will be a tough sell.

I have seen this in airplanes - large commercial aircraft use 400 cycle AC
mains power distribution, and various converters (synchromotors, etc.) in
an effort to save weight. I've also seen the trend for newer light aircraft
to have 24 volt systems instead of 12 volt systems - again, weight savings
despite increased power needs. I watched a guy convert a Beech Bonanza from
12 volts to 24 volts because they had a big aerial photo camera in it that
took all 1200 of the available 1200 watts in the aircraft - the conversion
was a HUGE job, but the result was the camera was happy and there was
enough electrical capacity to run the rest of the systems on the airplane.

Remember Phil's comment about an Audi being a computer that happens to have
a car engine embedded somewhere in it? It is going to get lots worse . . .
better learn to use your multimeter real well!

Best Regards,

Mike Arman