AutoblogGreen

I hope they drop this in the Tahoe/Yukon/Suburban. I'm interested to see the mpg ratings.

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There has to be a better way! It’s hard to believe that after all this time GM can’t do better than the reciprocating piston engine. http://peswiki.com/index.php/Directory:Engines

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seems like some very innovative solutions for getting a bigger diesel in where a smaller gas engine would typically reside

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Am I missing something in engine design? Why is it that there are so many cylinders? In a gas engine you are limited in the size of the combustion chamber because the flame has to propagate from one point (the spark plug), but in a compression ignition cylinder the whole mass erupts into flame when the pressure gets high enough. And since power generation goes up with volume, but parasitic heat loss goes up with surface area, I would think larger combustion chambers would be more efficient.

The lumpy power delivery probably isn't much of an issue, all you need is a big fly-wheel (which you need anyway).

Is it just that Americans think a 4-cylinder is for wimps?

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It's pretty obvious by now that the next generation of motors will be electric. That being the case GM is unwilling (as they should be) to spend 5 years on new ICE engnes, and tooling for such when in 10 years serial hybrids and all electrics will rule new production.

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GoodCheer,

I'm not an engineer or anything, but I had a couple of thoughts about your comments - I thought maybe the advantage of having more cylinders rather than bigger ones is that it provides more combustion cycles per revolution and therefore could maybe provide for a smoother running engine with less vibration, or perhaps that it would make overcoming those issues easier?

Another thought that came to mind is heat dissipation.

Those were just a couple of things that came to mind, but I don't really know one way or the other. I'm sure those issues can be overcome by good design.

I also think you are right about the perception about more cylinders being better - I see more and more cars on the road with badges proudly displaying their V6 or V8 status. Formula 1 cars have a 2.4 liter V8 that makes somewhere in the neighborhood of 800-850 horsepower, yet it's smaller in displacement than many 4 and 6 cylinder engines out there. Of course, it's all marketing - there are people who have no idea how big the V8 is, but they want it.

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Flame propagation isn't too much of a problem for low revving production engines.
F1 engines would benefit from triple spark plugs, but the rule nannies say no. They operate up to a governed 19,000rpm. Before the rules forced a 98mm bore maximum, 20,000 rpm was achieved with larger bore/shorter stroke V10s.

http://www.epi-eng.com/ET-PistonExcit.htm
An engine needs 7 cylinders for net positive torque, but who makes one of those? 5 cylinders for gross positive torque-the firing interval is 144 degrees, but at a crank/rod angle from 36 degrees from BDC the torque out is almost 0, and the longer crankshaft and harder exhaust manifold over an inline4, are real disadvantages for the Inline5 (they fit transversely, that is why volvo uses the)

An inline3 is best because of ease of exhaust manifold design/manufacture, firing interval 240 degrees, and camshaft duration (no crosstalk in exhaust manifold)
So you double that up for an inline6, boxing 6, or V6. Double an inline6 for a V12.

Having net positive torque reduces potentially damaging torsional oscillations, reduces lugging which can damage bearings. But semi tractor trailers operate with Inline6s.
But modern manual transmissions have dual mass flywheels, and automatics have continuous torque converter clutch slip, and have isolator spring (ZF was really proud of the dual spring isolator on the new ZF 6HP21,28,34 models)

and people's (great?) grandfathers liked the sound of a crossplane crank V8 L R L L R L R R.
It was noise, not power. But they liked it never the less.

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Guys this is a diesel engine. Flame propagation-in a diesel. Combustion starts after the fuel is injected. The more cylinders the smother the engine runs. The more cylinders the engine has the easier it is to sell.

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More cylinders probably helps with emissions as well.

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do you think it can fit in a 1997 s10

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I read nothing in the GM release about the Dynamax 4.5L being available in a Chevy 3500 Express Van which are used by many Class B RV manufacturers. Do you think it would fit in place of the current 6.0L gas engine? What would the increase in cost be and what transmission would they couple to it? Many thanks. Don

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Well I hope GM uses a six speed and drops the stupid four speed. Having my 4th GM product, 4 speed is not the best for towing. Six is so much smoother though the final gear ratio is the same between 4 and 6.

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The 72-degree cylinder block angle was chosen for more than just compactness. A 72-degree block angle is optimum for a V-10 engine. GM intends to create a new diesel engine family, not just the 4.5 version. In so doing, GM has chosen the same path as Mercedes, whose V6 diesel is also 72-degree block angle and therefore easily expandable to a V-10.

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Man, there is some confusion going on here-
Flame propagation is the same between gas and diesel engines- in a diesel, the fuel isn't injected until just before the maximum pressure and temperature is achieved. If it was a random thing, "Once the pressure is high enough", the engine would not run.
A diesel needs a certain amount of compression to achieve ignition, historically between 14.5:1 and 21:1 in automotive use. A very small combustion chamber is needed to achieve these numbers in a small engine. And Good Cheer, please go back and see how many times you contradict yourself in your first post. How can a larger combustion chamber be more efficient if a higher compression ratio makes more power, and if more surface area increases parasitic heat loss?
More cylinders=smoother power, although some of that is lost in the vee angle. This is nothnig new for GM, though, they built the 4.3l with a 90º vee to share parts with the smallblock v8s. This engine is getting a shallow angle to fit in a certain space.
Mike W-
I hope you don't have TCC slip- that's a sign of a bad torque converter clutch. The net slip should be under 5%, or it will trip the check engine/check transmission light and set a code in the computer. The torsional vibration won't be noticeable since the clutch will be unlocked until about 1600rpm in top gear(if they do it the same as their other engines).
Don- If the 6.6l fits, this will fit with room to walk around it.

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I have been wanting this for some time. I am sure the techs and engineers at GM know their game. I trust them. My question is...when is a chip available! I love diesel power!

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There will be many injection events on these engines. Before and after the main injection event in order to cool the cylinder to reduce NOx and noise and after the main event for the same reasons and possibly to promote regeneration in the diesel particulate filter. Forget your flame propagation comments. 30k psi pressures and bowl designs can handle cylinder sizes. They will still want this engine to do truck work and straight six is too tall and long a V8 makes common sense. A diesel four would have to have the same liter size to do the same work and would be too noisy to be accepted here. As one whose driven a 1.9L passat, the thing is anemic and not capable of the performance we need here. And get off the Euro superiority kick on diesels. Yes F-1 small liter v8's kick butt, but Audi uses a V10 in diesel race engines and VW uses the V10 in a little SUV here in the states. A V10!!! You want to complain about a V8 in a full size p/u that may actually carry a load? The VW Toureg will only be carrying a yuppie wife and a kid to soccer practice.

The biggest miss is that as modern and new as they say this engine is, they still have to use urea! How stupid is that. All these great ideas on packaging and they still have to use SCR. Oh well. I guess its the path of least upfront cost complexity on the manufacturer and puts the burden on the consumer. Dodge will also be going with a V8 diesel from Cummins, V8, 5L. Fit wherever a Hemi fits...gives all kinds of ideas for a diesel Chrysler 300 or Charger huh?

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This news of a new design DuraMax 4500 diesel turbocharged with direct injection is very exciting news to me. I have a '97 GMC Sierra that is still in factory new condition but optioned with the Vortec 4300 L35 gas engine. Oh the engine is wonderful and still runs like new but it's not a diesel. I have considered many options to re-power this chassis but it all comes down the weight and size issues. The DuraMax 6600 TDI is a wonderful engine but way too much motor for what I use my pickup for. Since this new DuraMax 4500 TDI will mount and hookup to existing small-block infrastructure this means little or no major mods will be needed to mount in current chassis and mount to existing 5-speed manual transmission. Why would I want to pay $30K to $50K for a new truck with this engine combo when I can use my existing infrastructure and have a brand new 1997 GMC Sierra SL repowered with the DuraMax 4500 TDI for less than $10K. Chevy/GMC finally did something right when they built a vehicle that doesn't rust or fall apart after 10 years. Repowering my existing chassis will allow vehicle life to be extended to more than 1 million miles or 20 to 30 years before replacement. Who would've ever thought such a thing possible 40 years ago.

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mexglx- SCR is the only proven, economic way to make a LARGE diesel pass T2B5 regs. I realize Dodge/Cummins isn't going that route, but there may be problems down the road. MB cannot seem to get there with the 3l Bluetec. SCR is not such a bad thing.
James- You might be able to find a good 2.7L from a sprinter to use. It would fit real easy and get awesome mileage.

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I am no where near understanding what most of you are talking about, however, I have purchased a 08 Suburban on lease waiting for the new diesel engine. I owned a HD2500 with the larger duramax and loved it, however, here are my un-tecnical questions maybe some of you can answer:

1. What MPG might the new engine get?
2. Since the Oil companies are now killing us with
the fuel costs, will this run on Biodiesel?
3. Will this engine use the same cylinder shutdown
mode?
3a. Why can't the cylinder shut down mode stay in
4 cylinder mode when on cruise control and not
pullng a trailer? I put 40thousand miles on a
year in the midwest and hope GM makes the
computer stay in 4 cylinder mode. Give us
drivers the opportunity to use the mix using
geography and trailer/no trailer modes.
4. Will this motor go in the regular Suburbans?

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