GM focusing on improving light truck fuel economy - GreenHybrid

Jason · #1 (**permalink**) 05-19-2005, 08:11 PM

Sounds a lot like Honda's system to me. Since when did GM have this ability?

Quote:

General Motors is bringing new hybrid and gasoline engine technology to bear to help boost fuel economy of light trucks.

Displacement on demand (DOD) is what Brian McVeigh, general manager for GM’s Fleet & Commercial division, believes should offer the biggest boost to light truck fuel economy. DOD turns engine cylinders “on” and “off” depending on how much power the vehicle needs at any one time. That would give GM’s V-8 engines the ability to sip gasoline like a V-4 in light inner city and steady highway driving conditions, said McVeigh.

http://fleetowner.com/news/gm_light_...conomy_051905/

iboomalot · #2 (**permalink**) 05-21-2005, 03:30 PM

Since the late 1970s early 80s. 1981 maybe before. Us old folks will remember the V-8/6/4 Caddy

see if I can find you a link to some info

"4. Cadillac V-8-6-4 - In the early 1980s, Cadillac started to feel the heat from Mercedes-Benz and BMW. Already bruised by the diesel debacle, Cadillac wanted to make a grand engineering statement.

The V-8-6-4 - GM's first attempt at cylinder deactivation - did make a statement, but not the kind that Cadillac wanted. The engine bucked and jerked. The transition of the cylinders turning off and on was so rough and unreliable that it angered many Cadillac owners.

But the idea behind the V-8-6-4 - to shut off the flow of oil to the lifters and close down cylinders - was a good one. Unfortunately, the sensors and computing power to make the system work seamlessly just wasn't available back then.

Flash-forward to today. GM is in production with its Displacement on Demand cylinder-deactivation system on its mid-sized SUVs. Powerful computers shut off the flow of oil to the valve lifters, which turns off half the cylinders when at highway cruising speed. This gives about a 5 percent fuel economy gain and costs GM just $50 per engine to install.

The system works so smoothly, drivers don't know it's there. Chrysler has a similar system for its hot-selling Hemi V-8s."

http://www.autosafety.org/article.php?scid=77&did=1091

"A terrible idea in 1981 may be the solution for increased fuel economy in the new century.
We're speaking of the short-lived Cadillac 8-6-4 engine that proved a major flop in 1981. General Motors, which suffered a major black eye with the 8-6-4 failures, is looking to bring back a version of that engine.

GM's Powertrain Group's executive director for advanced engineering Fritz Indra said he believes the time is ripe for cylinder deactivation, the technology behind the old 8-6-4. Mr. Indra said it is the simplest and least expensive way to improve fuel economy. "

http://www.highbeam.com/library/doc0...eyword=&teaser=

iboomalot · #3 (**permalink**) 05-21-2005, 05:30 PM

What I just thought would be cool is if that technology could be put into a TDI motor

V-6 TDI that could be a 2 or 3 banger on the HWY and also put in some electric and you have a diesel sipping POWERFULL when needed engine.

That would rock 175hp 300 ft/lbs and 50+ city 70+ hwy would rock.

just a thought.

hope the links helped have fun

treefarmer · #4 (**permalink**) 11-28-2006, 09:59 AM

If the cylinder deactivation only costs $50.00 can it be added to an existing V6 Sonnoma pickup as an after market add on?

AshenGrey · #5 (**permalink**) 11-28-2006, 06:51 PM

It seems to me that DoD and FAS would be a good way to modestly improve FE on the cheap for a wide variety of trucks. From what I've read, FAS is a bit more useful than BAS since it can energize several 110v power outlets.

So... How much tweaking would be required to upgrade FAS into something resembling a 1st-gen IMA?

martinjlm · #6 (**permalink**) 12-09-2006, 07:50 PM

Quote:

Originally Posted by treefarmer

If the cylinder deactivation only costs $50.00 can it be added to an existing V6 Sonnoma pickup as an after market add on?

No. An incredible amount of vehicle integration is required to deal with the shifting back and forth. Imagine the balance issues involved with having your V6 engine fire on only three cylinders as opposed to its more natural 6 cylinders. On side of the engine would be firing on two cylinders while the other is firing on one. Continuously.

GM's applications that have Active Fuel Management (AFM) require special engine mounts tuned to adapt real-time to the engine's shift in operating mode. This also requires very sophisticated algorithm management to make certain all the impacted computer modules in the car know when the engine is in full mode or half mode.

Peace,

Martin

martinjlm · #7 (**permalink**) 12-09-2006, 07:52 PM

Quote:

Originally Posted by AshenGrey

It seems to me that DoD and FAS would be a good way to modestly improve FE on the cheap for a wide variety of trucks. From what I've read, FAS is a bit more useful than BAS since it can energize several 110v power outlets.

So... How much tweaking would be required to upgrade FAS into something resembling a 1st-gen IMA?

You will see AHS-2 applications with AFM (the trademarked acronym for Active Fuel Management, which is the actual name for GM's "Displacement On Demand system).

Peace,

Martin