GM's new diesel opens up, loses weight

[Ming]

GM's new diesel opens up, loses weight
October 21, 2008

DETROIT -- Henry Ford once said the best engineering is to "simplicate and add lightness."

Charlie Freese and Gary Arvan don't work for Ford Motor Co. But the new diesel V-8 they designed for General Motors is simple and light. On paper, at least, it has the potential to be the first great engine of GM's second century.

Open up the bottom half of the Duramax 4.5 and you'll see things GM has never done in the crankcase of a regular production engine.

Start with the crank journals, the center section of the engine block that holds the crankshaft. They are cast into the block, but not in the usual way. GM used the same type of process, fracture splitting, for the main journal bearing caps that it uses on its connecting rods.

The result is greater precision, higher strength and lower costs on two fronts. The process needs less of the expensive compact graphite iron material for the block and bearing caps. Machining costs drop because the engine uses two bolts per bearing cap, not four.

It's a novel design for a diesel engine. A diesel's high compression ratio puts the crankshaft and bearings under tremendous stress and strain. Most diesels have heavily cast crankshaft bearing journals. GM's may be the lightest ever, with open spaces where you'd normally see thick metal.

The design of the crankcase also led to better circulation of air between the banks of cylinders. Because the sides of the bearing journals are not cast into the wall of the cylinder block, air can circulate freely as the pistons move. That reduces what engineers call pumping losses that sap performance as the engine turns over.

"One of the big issues for these modern diesels is the ability to handle the exchange of pressures through the crankcase itself," Freese said.

Because GM has not built a gasoline or diesel engine with a similar design, Freese declined to say how much weight or machining costs the new engine saves. But he said it was substantial and that some of the 4.5-liter engine's features likely would be used in future gasoline and diesel engines.

The lower engine's design helps meet two other design goals: Deliver at least a 25 percent fuel economy gain over a similar-size gasoline engine, and meet the toughest emissions standards on the books. GM plans to build the engine tuned just one way, with one emissions system, and offer it in all 50 states.

Some other unique features of the engine include:

-- A hollow balance shaft with a gear-driven center section that transfers internal noise to the rear of the engine near where the transmission is mounted. The noise is muffled by the heavy transmission housing.

-- An aluminum cradle or upper oil pan that mounts between the engine block and the lower oil pan that stiffens the engine block. Said Freese: "We get a 30 percent stiffness improvement compared with any other benchmark design."

(Source: Automotive News)

http://reviews.cnet.com/8301-13746_7-10070295-48.html

[nadepalma]

Nice find and good write up. Glad to see GM taking the lead on a new approach to engine design and manufacturing.

I hope this engine does make it into the STS, CTS, and possibly GM's GMT900 products. Would be an excellent selling point and "performance alternative" for those looking for more economical thrills.

Next step: Get the 2.9L diesel V6 based on this engine up and running. It would be much better suited for the European market.

[paul8488]

Ah, GM at its best. When they want to be they're a brilliant company. Hope this new engine is a big success for them. The fuel savings could be very enticing for truck buyers.

[toddr19]

Sounds bitchin

[stevecmh]

Originally Posted by nadepalma

Nice find and good write up. Glad to see GM taking the lead on a new approach to engine design and manufacturing.

I hope this engine does make it into the STS, CTS, and possibly GM's GMT900 products. Would be an excellent selling point and "performance alternative" for those looking for more economical thrills.

Next step: Get the 2.9L diesel V6 based on this engine up and running. It would be much better suited for the European market.

agreed. i want to see some form of it in cars too.

[1931Chevy]

I think this engine will be good for European use but the US customer will not want to pay the extra money and the higher diesel fuel as it has been of late

[jckjds]

Originally Posted by 1931Chevy

I think this engine will be good for European use but the US customer will not want to pay the extra money and the higher diesel fuel as it has been of late

They should be able to sell quite a few of them in trucks. I think this would be a great replacement for the Duramax. It will be a little less powerful, but seriously, the Duramax can pull more than the frame can handle, anyway, so who cares? This should get quite a bit better fuel economy than the Duramax and be more economical/practical for the average truck user (i.e those who would otherwise choose a gas engine). Truck duty is also an area where the added cost can be recouped (considering fuel economy gain, long term use, and resale value).

As for cars, this thing is entirely toooooo big. Hell, I think the 2.9 is a very big diesel for a car. I'd like to see the 2.9 for big cars like the Caddy's and a much smaller unit for midsize and compacts (maybe a 1.0-1.4 liter?). That size of engine would produce the kind of eye-popping fuel economy numbers that would convince people to switch from gas to diesel.

Just my 2 cents.

[big swede]

So how much does it weigh then?

[ogg vorbis]

Originally Posted by jckjds

They should be able to sell quite a few of them in trucks. I think this would be a great replacement for the Duramax. It will be a little less powerful, but seriously, the Duramax can pull more than the frame can handle, anyway, so who cares? This should get quite a bit better fuel economy than the Duramax and be more economical/practical for the average truck user (i.e those who would otherwise choose a gas engine). Truck duty is also an area where the added cost can be recouped (considering fuel economy gain, long term use, and resale value).

As for cars, this thing is entirely toooooo big. Hell, I think the 2.9 is a very big diesel for a car. I'd like to see the 2.9 for big cars like the Caddy's and a much smaller unit for midsize and compacts (maybe a 1.0-1.4 liter?). That size of engine would produce the kind of eye-popping fuel economy numbers that would convince people to switch from gas to diesel.

Just my 2 cents.

it IS the duramax replacement. as for physical size/weight, it's the same size as the LS v8. it could possibly be lighter than the cast iron block LS v8. if you mean more cylinders than is necessary to push a car around, then yes.

i imagine you don't think 6.2L v8 are good either. maybe an e-flex in the corvette? all kidding aside, trucks *should* be gas/diesel-electric. a small engine/generator; no battery.

no gas engine exists that makes 520 lb-ft torque, and gets 25 mpg...in a truck no less. i could see a cadi getting 30+ mpg hwy with this diesel.

look for hcci (as opposed to diesel) in small / mid-sized cars. i know there's a 1.8L hcci, and i expect a v6 to follow.

[Buick Riviera]

Originally Posted by ogg vorbis

it IS the duramax replacement. as for physical size/weight, it's the same size as the LS v8. it could possibly be lighter than the cast iron block LS v8. if you mean more cylinders than is necessary to push a car around, then yes.

i imagine you don't think 6.2L v8 are good either. maybe an e-flex in the corvette? all kidding aside, trucks *should* be gas/diesel-electric. a small engine/generator; no battery.

no gas engine exists that makes 520 lb-ft torque, and gets 25 mpg...in a truck no less. i could see a cadi getting 30+ mpg hwy with this diesel.

look for hcci (as opposed to diesel) in small / mid-sized cars. i know there's a 1.8L hcci, and i expect a v6 to follow.

So gm has hcci four cylinder engine's and a hcci HF v6 engine ready to go? cool!!

[AMERICA 123]

In addition to all the good news here for diesel, down the road it would be nice to see this architecture become the basis for a turbo gasser - ideally on the same line.

****************************8

I could see this TD going into any number of older vehicles as well as a post production crate motor .

Later on, a more power dense derivative 3.5 - 4.0L V8 TD would be nice as well - maybe after that a 3.0L or going the other way possibly a 5.0.

Any way, throw some of the harder to develop for diesel - 'other tech' on this, ie start stop / MDS - AFM etc and its gets to go even further with FE.

A 100 HP/ L is not unrealistic ( hopefully) for future developments on power.

[jckjds]

Originally Posted by ogg vorbis

it IS the duramax replacement. as for physical size/weight, it's the same size as the LS v8. it could possibly be lighter than the cast iron block LS v8. if you mean more cylinders than is necessary to push a car around, then yes.

i imagine you don't think 6.2L v8 are good either. maybe an e-flex in the corvette? all kidding aside, trucks *should* be gas/diesel-electric. a small engine/generator; no battery.

no gas engine exists that makes 520 lb-ft torque, and gets 25 mpg...in a truck no less. i could see a cadi getting 30+ mpg hwy with this diesel.

look for hcci (as opposed to diesel) in small / mid-sized cars. i know there's a 1.8L hcci, and i expect a v6 to follow.

I thought this was going to be sold alongside the 6.6 duramax, but I hope you're right.

As for the bigger gas engines, no, I'm not against them. I drive a G8 with a 6.0 and love it for the performance. However, diesel is about torque and fuel economy, not performance. Because diesel engines are more expensive to purchase and operate, I am in favor of using diesel in the ways that best utilize its strengths.

Thus, I am in favor of using diesels in trucks. This application makes perfect use of the additional torque, and fuel economy (bc trucks are fuel hogs and, therefore, stand to gain the most). Plus, trucks tend to stay in service for longer periods of time, utilizing the diesel engine's longer service life.

As for cars, the best way to utilize diesel is to maximize the fuel economy benefits. Diesel's big advantage there is that a much smaller diesel can propel a given car when compared to a gas engine (due to the greater torque). Thus, small displacement diesels are appropriate to produce the kind of fuel economy gains that will provide adequate fuel savings incentive to attract purchasers who are willing to fork over the extra $3-5K that the diesel's cost (in addition to paying extra for fuel). I think that putting very large diesels in cars is a big fat waste of time, effort, and money. Who would by a massive deisel engine for an extra $5K, when you can get better straight line performance out of a big gas engine? Sure the massive diesel can get a little better fuel economy, but not enough to make up for the fact that the diesel fuel is more expensive than gas AND the additional up front cost. Plus, the extra toque of such a large engine goes to waste in a car bc cars can't tow a substantial amount of weight anyway.

That's all I was saying.

[AMERICA 123]

For the future, Diesel is a natural for high performance in both cars and trucks as well as for high fuel economy applications.

[chevypowa670]

Originally Posted by ogg vorbis

it IS the duramax replacement. as for physical size/weight, it's the same size as the LS v8. it could possibly be lighter than the cast iron block LS v8. if you mean more cylinders than is necessary to push a car around, then yes.

i imagine you don't think 6.2L v8 are good either. maybe an e-flex in the corvette? all kidding aside, trucks *should* be gas/diesel-electric. a small engine/generator; no battery.

no gas engine exists that makes 520 lb-ft torque, and gets 25 mpg...in a truck no less. i could see a cadi getting 30+ mpg hwy with this diesel.

look for hcci (as opposed to diesel) in small / mid-sized cars. i know there's a 1.8L hcci, and i expect a v6 to follow.

its not the duramax replacement, GM just spent millions on improving the current 6.6. they aren't getting rid of it any time soon.

[ChevyRacing48]

The 4.5 is not a 6.6 duramax replacement, that's a crazy rumor at best.

If it is somehow true, than GM just lost a life long customer to the 6.7 Cummins.