This is something I received today and thought it would be some good reading for ALL levels of installers. I think this would make alot of installers cringe if this actually went through, not to mention how much we will have to customize and bypass all this stuff . It's bad enough with all the new crap that GMC and other manufacturer's are putting into the cars to make upgrades a pain in the @$$. What do you guys think of this new 42 volt system ??
by: D. Lee
Our desire for cool vehicles and a wide variety of optional features
had to hit a wall someday. We are now close to not having enough
electrical power in today's cars to electronically manipulate the
engine while feeding everything from under car neon and audio/video
systems to game consoles. Fortunately, the automakers are looking to
the years ahead just to stay current and, as a result, have already
formulated a response to our insatiable power needs.
With the automotive platform and its own onboard computers and
convenience options sucking electrical energy at an unprecedented
rate, there is a need to either cut back on demand or increase power
generation. Efficiency only goes so far, before the need for more
power takes over. There are two ways to get more power: increasing
the amount of current, or increasing the voltage. Up to this point,
carmakers have been increasing current, since it was much cheaper to
increase the size of an alternator and throw in a few more circuits
than it was to reconfigure an entire car to operate on a different
voltage. The time has come where the cost and weight of expensive
copper wire has joined to push the issue, and the 42-Volt electrical
system will be the solution.
The benefits of a 42-Volt electrical system are many. The first one
that always comes to my mind is the reduction of copper wire
required in the vehicle. By increasing voltage, the current can be
reduced to maintain the same power, with the benefit that the
thickness of the wire can be reduced. This saves manufacturing cost
and performance-sapping weight. But there is a lot more to it than
simply saving on the cost of the wiring harness.
One of the main design changes in a full 42-Volt vehicle will be the
elimination of the conventional alternator and starter motor. Since
the alternator only runs when the engine is on, and the starter only
runs when the engine is off, these two nearly identical objects will
be replaced with the Integrated Starter-Generator (ISG) that can
perform both tasks. Subtract another 5 to 10 kilos of weight, and
the carmaker can hit performance and fuel economy targets.
The engine would also have parts like the camshaft made essentially
redundant, which could be replaced at 42-Volts. Instead of the
limited capabilities of the camshaft, each valve would be operated
by a solenoid like the flippers of a pinball machine. The benefits
available are exciting. The timing and duration of each valve can be
controlled electrically and changed on the fly by the engine
management computer. A simple twist of a dial could change the
engine from a smooth-idling factory setting to the lumpy cadence of
a `69 Chevelle with a 396 cubic inch engine fitted with a full
race
cam. If you have ever purchased a performance camshaft for you car,
you know they are not cheap or lightweight. At the lunatic fringe,
imagine being able to "hack" your own valve timing with a
laptop!
When fuel efficiency is considered, the ability of the engine to
simply turn off half of the cylinders while highway cruising will
save enough fuel to please environmentalists. Stab the gas pedal and
power is quickly restored for passing and other spirited maneuvers.
And subtract another five kilos of expensive machined steel.
On the entertainment side, extra voltage means extra output
potential. Ohm's law tells us that by tripling the voltage of a
product while maintaining the same current, we get triple the power
consumption, which means up to triple the output. If your current
AM/FM/CD player is rated at 25 Watts per channel, by rights you can
expect up to 75 Watts per channel from the 42-Volt version! It
should also run cooler.
There are two major technical challenges currently on the table. One
involves the transition into the 42-Volt world. Carmakers won't
commit to 42-Volts because there are very few 42-Volt components
available from both Tier one and Tier two parts providers. For
example, if GM buys parts and subassemblies from a supplier like
Magna, and Magna has no 42-Volt stuff available, GM can't build
the
car. On the other hand, a parts manufacturer like Magna won't
invest
millions of dollars to produce 42-Volt components for a car that
does not exist.
This is the classic, "what came first the chicken or the
egg?"
question. Whoever steps up to the 42-Volt plate first will waste
huge amounts of money waiting for the other side to respond. The
automotive industry has a lag time of somewhere around five years
from concept to showroom floor, and that doesn't help. In
contrast,
the mobile electronics industry, renowned for its ability to react
fast, would only have to wait around for about four months before
their collaborators introduced the missing pieces to a particular
puzzle.
The logical alternatives to jumping head first into 42-Volts
involves a variety of dual-voltage combinations. The first 42-Volt
vehicles could have a 12-Volt system with a special 42-
Volt "inverter" to power a limited number of new 42-Volt
devices.
Eventually, the switchover would be made to an entirely 42-Volt
platform.
Or, the carmaker could build a 42-Volt foundation with a large 12-
Volt converter to power the bulk of existing technology, eventually
phasing out the converter when the migration is complete.
The third option is to use two electrical systems, one based on a 12-
Volt battery and alternator and a second one with a 42-Volt ISG and
battery. This offers a bit of redundancy in case one alternator
fails, you don't lose both voltage busses.
The other major technical challenge comes from 42-Volts itself. As
switches are turned off and on, electrical energy jumps between the
tiny initial gap as the switch's contacts open. This is termed
"arc"
and is exactly what you want in a spark plug, but what you don't
want in a switch contact. The size of the arc is dependent on the
amount of current drawn. For instance, the starter draws so much
current, it needs a giant relay called a solenoid so the contacts
don't simply burn off in a week. As you probably know, a starter
solenoid rarely fails in a vehicle less than 15-years-old. But at 42-
Volts, the arc is no longer a quick snap. Instead it hangs around
indefinitely, melting contact metal and generating "arc
welder"
levels of heat.
This problem is called "sustained spark" and occurs when you
get
somewhere around 40-Volts or more. Imagine turning off your
headlights and they stay on until you disconnect the battery or
until the switch contacts have fully burnt off of their mounts!
Obviously, this little obstacle is a deal breaker when it comes to
evolving to 42-Volts. Higher voltages want to keep flowing even when
the switch is off and that little detail will be the most
unpredictable.
In any case, there will be a premium to pay during the expensive
adoption period. I believe the final outcome will be worth it. The
extra voltage will enable all systems in the vehicle and all
aftermarket devices to see a great performance gain. In-car
computing will become more viable and the configurable instrument
panel will make our interiors much cooler. In addition, you can
expect a whole new family of in-car products that just don't
exist
now because of inadequate voltage.
Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA
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