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GM Powertrain Unveils 3.6-Liter VVT Engine With DI

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PONTIAC , Mich. – GM Powertrain announced today it will deliver a 3.6-liter V-6 gasoline engine with direct injection and variable valve timing (VVT) technologies in the 2008 model year. A vehicle application will be announced later in the year.

Additionally, it was forecast that by the end of 2008, GM will produce as many as 200,000 vehicles globally with direct injection technology, and by 2010, GM projects one out of every six GM vehicles in North America will be equipped with a direct injection engine.

The application of direct injection technology to the 3.6-liter VVT engine – a member of GM Powertrain’s family of high-feature V-6 powerplants used on cars and trucks around the world – contributes greatly to a 15-percent increase in horsepower over the current levels that range from 240 to 267; an 8-percent increase in torque, and up to a 3-percent improvement in brake-specific fuel consumption (BSFC). An approximate 25-percent reduction in cold-start hydrocarbon emissions is also achieved.

With direct injection, precisely metered fuel is delivered directly to the combustion chamber, which has a cooling effect in the chamber. Cooling the incoming air charge enables a higher compression ratio, which also improves engine efficiency. Less fuel is required to produce the equivalent horsepower of a conventional port injection combustion system.

“The 3.6-liter VVT with direct injection will be our highest specific output non-turbocharged V-6 engine, as well as one of the most fuel-efficient offerings in our high-feature family,” said Tim Cyrus, chief engineer for high feature V-6 and Northstar V-8 engines. “It’s the latest example of our strategy to continue to reduce emissions and improve fuel economy without sacrificing performance.”

This is GM’s third engine with gasoline direct injection. The announcement of the 3.6L VVT V-6 with direct injection comes on the heels of the introduction of GM Powertrain’s Ecotec 2.0-liter four-cylinder Turbo engine with direct injection on the 2007 Saturn Sky Red Line and Pontiac Solstice GXP roadsters. Also, since 2004, a naturally aspirated Ecotec 2.2-liter direct injection engine is equipped on Opel models in Europe.

How direct injection works

Direct injection differs from the fuel delivery process of a conventional engine by delivering fuel directly into the engine cylinder, where it is mixed with air. The combustion process of conventional fuel injected engines uses air and fuel that partially evaporates in the intake port or intake manifold prior to being introduced into the combustion chamber. Direct injection is a continuation of the evolutionary process of moving the fuel introduction point closer to the cylinder to improve control.

With the 3.6-liter VVT with direct injection, fuel is introduced directly to the cylinder during the intake stroke. As the piston approaches top-dead center, the mixture is ignited by the spark plug.

The fuel injectors are located beneath the intake ports. The intake ports only transfer air, unlike port fuel injection, which flows air and fuel, thus increasing efficiency. D irect injection also permits a slightly higher compression ratio than if the fuel were delivered with conventional fuel injection. The result is better fuel consumption at part and full throttle. The engine uses conventional spark plugs similar to other high-feature V6 engines.

A high-pressure, returnless fuel system is employed. It features a high-strength stainless steel fuel line that feeds a variable-pressure fuel rail. Direct injection requires higher fuel pressure than conventional fuel injected engines and an engine-driven high-pressure fuel pump is used to supply up to 1,740 psi (120 bar) of pressure. The system regulates lower fuel pressure at idle – approximately 508 psi (35 bar) and higher pressure at wide-open throttle. The exhaust cam-driven high-pressure pump works in conjunction with a conventional fuel tank-mounted supply pump.

Direct injection’s fuel delivery enables very efficient combustion to help reduce emissions, particularly on cold starts – the time when most tailpipe emissions are typically created. Also, direct injection permits a higher compression ratio – greater than 11.0:1 in the case of the 3.6 – which has a positive influence on fuel economy.

3.6-liter VVT DI

The 3.6-liter VVT DI is based on GM Powertrain’s sophisticated 60-degree dual overhead cam (DOHC) V-6 engine. It is the latest member of a growing family of GM Powertrain V-6 engines developed for applications around the world, drawing on the best practices and creative expertise of GM technical centers in Australia, Germany, North America and Sweden.

Features found on the 3.6-liter VVT DI include:

-Aluminum engine block and cylinder heads

-Dual overhead cams with four valves per cylinder and silent chain primary drive

-High-pressure, engine-driven fuel pump

-Advanced multi-outlet fuel injectors developed to withstand high pressure and heat

-Stainless steel, variable pressure fuel rail

-Four-cam phasing (VVT – see description below)

-11.3:1 compression ratio

-Aluminum pistons with floating wrist pins and oil squirters

-Polymer coated piston skirts

-Forged steel crankshaft

-Sinter-forged connecting rods

-Structural cast-aluminum oil pan with steel baffles

-Electronic throttle control with integrated cruise control

-Coil-on-plug ignition

-Advanced direct injection capable engine control module (ECM)

-Optimized exhaust manifolds with close-coupled catalytic converters

-Fully isolated composite camshaft covers

-Outstanding noise, vibration and harshness control

-Maximum durability with minimum maintenance

-Common manufacturing practices for efficiency and exceptional quality

-Four-cam phasing

The 3.6-liter V-6 VVT DI employs four-cam phasing to change the timing of valve operation as operating conditions such as rpm and engine load vary. The result is linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (maximum horsepower per liter of displacement) without sacrificing overall engine response and driveability. When combined, direct injection and cam phasing technologies enable an unmatched combination of power, efficiency and low-emissions in gasoline V-6 engines.

Cam phasing pays big dividends in reducing exhaust emissions by optimizing exhaust valve overlap and eliminating the need for a separate exhaust gas recirculation (EGR) system.

By closing the exhaust valves late at appropriate times, the cam phasers allow the engine to draw the desired amount of exhaust gas back into the combustion chamber, reducing unburned hydrocarbon emissions. The return of exhaust gases also decreases peak temperatures, which contributes to the reduction of oxides of nitrogen (NO x) emissions. In tandem with the dramatic 25-percent reduction in cold-start hydrocarbon emissions brought on by direct injection, the 3.6-liter VVT DI V-6 surpasses all emissions mandates, and does so without complex, weight-increasing emissions control systems such as EGR and air injection reaction (AIR).

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267 + (.15*267) = 307.05hp

Hopefully this isn't just a Caddy exclusive, and that this rolls out to the Zetas and all current FWD applications of the 3.6.

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uhm... which car does a 267hp 3.6 come in?

255 + 15% = 293hp

I wonder if they can find 7 hp in there somewhere for the '08 CTS.

Not a car, the 2007 Outlook, and yes, I think you can expect this engine in te 2008 CTS with about 300 hp and 270 lb-ft.

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Chances are that GM will under rate this engine, due to the gas/fuel price crisis, whether it's actual or perceved.

The CTS version should be rated at 295 hp, with 300 in the STS and SRX. 275 HP sounds about right for the Outlook and other future uses of this engine. It would also allow GM to raise their corporate CAFE, by selling more V6's.

It also gives GM room for future HP increases if the competition gets tough.

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Well, if this is the 300+hp V6 that guionM was referring to on CZ28, this would be awesome in the Camaro as a midlevel or (dreaming) base engine.

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This engine will probably be the bulk of those sales. I'm not sure how well they sell overseas, but the DI Ecotec in the Solstice/Sky will barely reach five-figure sales, if that. It's a pretty significant increase when you think about it. Maybe they're also working on a way to fit DI in the OHV engines.

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This engine will probably be the bulk of those sales. I'm not sure how well they sell overseas, but the DI Ecotec in the Solstice/Sky will barely reach five-figure sales, if that. It's a pretty significant increase when you think about it. Maybe they're also working on a way to fit DI in the OHV engines.

Those numbers do seem low..you would think they would eventually spread the use of this engine across all the mid size models and retire the OHV V6s..

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Chances are that GM will under rate this engine, due to the gas/fuel price crisis, whether it's actual or perceved.

The CTS version should be rated at 295 hp, with 300 in the STS and SRX. 275 HP sounds about right for the Outlook and other future uses of this engine. It would also allow GM to raise their corporate CAFE, by selling more V6's.

It also gives GM room for future HP increases if the competition gets tough.

the CTS MUST have 300+ HP from this to out-do the IS350 (305hp) and 07 G35 (300+ hp); both with V6's.

whether or not it's faster, that HP mindset is what makes a difference in the reviews and buyers mind.

I'm sure there will be a lower HP introduced later to do battle with the 325i, IS250 and the low hp Audi A4's

Edited by jbartley

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They need to either add DI to the Northstar motors or do away with them. The Northstars are becoming more and more pointless.

????

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This is the future Camaro V6. as well as many of the other RWD cars.

If priced well the V6 Camaro the most important Camaro would be the home run they need.

The more lines they can apply it too the cheaper they will be to build. Much the same way the Ecotech has been a well priced high tech engine.

Now one must ask how long till Direct Injection will show up on the new V8 engines?

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????

Besides the supercharged Northstars, they pretty much make the same power. Upgrade the Northstar V8 with DI or something, or get rid of it. It's becoming a dinosaur.

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They need to either add DI to the Northstar motors or do away with them. The Northstars are becoming more and more pointless.

Agreed. GM needs to update the Northstar ASAP. GM needs a premium V8 to compete with the Lexus/BMW/Mercedes V8 engines. In todays market 320 HP is nothing to brag about from a V8.

Hopefully the Northstar will get an update in the next 18-24 months to come out after this new 3.6L DI V6.

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Agreed.  GM needs to update the Northstar ASAP.  GM needs a premium V8 to compete with the Lexus/BMW/Mercedes  V8 engines.  In todays market 320 HP is nothing to brag about from a V8.

Hopefully the Northstar will get an update in the next 18-24 months to come out after this new 3.6L DI V6.

The Northstars are being updated as you speak. (and tested too)

1st car this this new Northstar pops up in? The Buick Lucrene. :)

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The Northstars are being updated as you speak. (and tested too)

1st car this this new Northstar pops up in? The Buick Lucrene. :)

Really? Based on what? How do you know this? Tell us more?

About the Buick... I would have thought that GM would have continued with tradition and introduced the new Norhtstar in a Cadillac - hopefully the coming updated STS for 2008/2009 MY.

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I think 200,000 by the end of 2008 is okay. The Zetas won't come on strong until 2009, so that means they should still be getting the DI. Also, note that it says 1 out of every 6 vehicles by 2010, so I assume that means trucks and SUVs too; I wouldn't expect many trucks or SUVs to get the DI except for the SRX and the Lambdas, so really its 1 out of every 2 1/2 cars probably. I'm guessing Aveos, most Cobalts, some Malibus, and most stuff that still has OHV V6s by then will not get DI.

The 200k by the end of 2008 probably means the CTS, possibly SRX and STS, and Holdens. What's important is the 1 out of every 6 statement in NA by 2010.

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That's what I figured, Northie. The 3.6DI is the first "volume" application of DI. Since it's being released in MY2008, the "200,000 by 2008" remark doesn't really hold much water. Obvoius future recipients of DI would be the rest of the Ecotecs and the HFV6s. I remember AH-HA saying something about the "Ultra V8" being canned in favor of a Northstar replacement and that DI was part of the deal, but someone can correct me on that if I'm wrong.

I still think it'd be interesting to see them come up with a DI system for their OHV engines.

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I'm sure that there will be more..just being understated...I'm sure. :)

No, probably not, after all they won't be selling many Solstice GXPs, Sky Redlines and Opel GT's, the CTS isn't very high volume and the 3.6 DI is only a fraction of that, and the bulk will still be coming from the 2.2 Direct in the Signum and Vectra. Since DI diesels make up nearly half of European volume I don't think they're being counted in this total.

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Truely good news. The Camaro, CTS and midsize-large RWD sedans are going to have at least one awesome technologically-advanced powertrain. GM cannot pair this engine with a 4-speed!

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great. thanks for releasing it in about two years. pooped on the party

just kidding. this truly is good news. DI will be a major improvement. Though I wish it was already coming for Caddy today, or for '07 model year....it is good to know this may finally spell the end of the HV engines. HV engines are only used in great numbers in America anyways....and most Americans don't care for them. To the chopping block.

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