Second
United Auto Workers Agreement Reveals General Motors' Potential
Future Truck Plans
By: Mike Levine  Posted:
10-01-07 12:30 PT
© 2007 PickupTruck.com
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Update
#1: 10-01-07 12:55 PT
I've
clarified my comment about SIDI being similar to a diesel.
Both diesels and SIDI engines directly inject fuel into
the combustion chamber. I've added text that diesels rely on
high compression ratios to auto-ignite the fuel-air mixture, whereas
SIDI motors still use a spark plug.
A
reader also brought to my attention that Honda uses cylinder
deactivation in its 3.5-liter SOHC V6 engine. My point - and
it should have been stated more clearly - is that cylinder deactivation
hasn't seen fuel economy returns worth the investment necessary
for a full size truck's overhead cam V8 - or else Toyota and
Ford would have offered this in their OHC V8s already.
------
This
is the toughest story I've written.
On
Friday afternoon I watched the newswires and Wall
Street Journal break information about GM's future
product plans that were revealed in the "White
Book" agreement between GM and the UAW settling last week's
strike.
One
of the items that caught my attention was the name of GM's next
full size truck platform, C3XX. So, I went and did some more
background searching on the 'C3XX' identifier, using Google.
To
my surprise a second, internal UAW-GM document appeared in
Google's search
results. The document
can be found on the Future
of the Union website and Google's publicly available search cache.
On
Friday the document ranked much higher in the search results,
before the "White Book" news containing the 'C3XX' term at more
popular websites moved up in Google's page rankings.
The
information about what's contained in that document is in the
story below.
After
wrestling with this decision, and consulting with several colleagues,
I've decided to publish this story because I believe it's relevant
to the "White Book" news and GM's current state of affairs
with the UAW.
-
M.L. |
A document
found online (using Google) at the Future
of the Union website suggests
that General Motors is preparing to substantially overhaul the engine
lineup used in its next generation full size trucks.
Future of
the Union has published
an internal memorandum of understanding that contains
detailed information about contract negotiations that took place in
June 2007 among the United Auto Worker (UAW) union, General Motors
(GM), and GM’s
largest supplier, Delphi.
The document
contains GM’s future product
commitments to UAW-represented employees at Delphi, similar to the
future product timelines
that emerged from the recent strike settlement
contract between GM and the UAW.
Most notable
are the powertrain components that Delphi is expected to supply for
use in the C3XX truck program, starting in 2011. The C3XX platform
will replace the current GMT 900 architecture that underpins the Chevrolet
Silverado and GMC Sierra full size pickups.
According
to the document, C3XX pickups will feature a new 'Gen V' 6.2-liter
dual overhead cam (DOHC) V8 engine - a major departure from GM's traditional
overhead valve (OHV) pushrod engine design used in its trucks, like
the ‘Gen
IV’ 403-horsepower / 417 lb-feet L92 6.2-liter V8 under the hood
of the GMC Sierra Denali. The only DOHC V8 GM currently offers is Cadillac’s
4.6-liter Northstar engine.
The Gen
V 6.2 motor will use variable valve timing (VVT) like the Gen IV 6.2,
but the use of dual overhead cams holds the promise of four valves
per cylinder instead of the current two valves, for better intake and
exhaust flow and increased power. This is a similar setup to the 5.7-liter
i-Force V8 used in the Toyota Tundra, but the Gen V 6.2 will also offer
GM's active fuel management (AFM) system. AFM shuts down half the cylinders
during steady state running for improved fuel economy – a feature
not currently available for the i-Force. Up until this point, it’s
been conventional wisdom that implementing cylinder deactivation on OHC
engines is impractical for reasons of cost and complexity.
Pushrod
engines won’t be disappearing entirely from GM’s
truck line. A new ‘Gen V’ OHV V8 will replace the current
320-hp / 340 lb-feet 5.3-liter V8. Apparently the final displacement
hasn’t been determined yet, because it’s referred to as 5X.
The
new 5X gasoline engine will feature spark ignition direct injection (SIDI),
similar to a diesel's fuel injection setup but still using a spark
plug to ignite the fuel instead of diesel's high compression ratio
that causes the fuel air mixture to auto-ignite. SIDI places the fuel
injector right inside the combustion chamber, so fuel can be directly
mixed with air entering the chamber during the intake stroke instead
of before it enters the chamber, like in a conventional multi-port
fuel injected gas engine. This approach enables a leaner burn of the
fuel at higher compression ratios than current gas engines, resulting
in greater fuel economy, cleaner emissions, and more power.
Initial
production of both engines is slated to start in 2011 with full production
in 2012.
Of course,
it's possible that because this information is still approximately
three years out in time, plans detailed in this document for the full
size truck powertrains could still change.
Contacted
for comment, a GM spokesperson told PickupTruck.com that GM doesn't
make statements about documents like this.
There was
no phone number or names listed to contact the Future of the Union
website for comment.
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