GM Brings Direct Injection to V6 Auto Engine

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jimh posted 09-15-2007 12:13 AM ET (US)
Since this press release a few months ago, GM has since announced it will use this new engine in the 2008 Cadillac STS. This is the third gasoline direct-injection (GDI) four-stroke engine for General Motors. The two prior engines were in their Ecotec four-cylinder series, motors of much smaller power and displacement.
-----
GM Powertrain Unveils 3.6-Liter VVT Engine With Direct Injection
Latest offering promises significant horsepower and torque increases, dramatic hydrocarbon reductions, improved fuel economy
PONTIAC, Mich. (Mar. 18, 2006) – 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).
Tohsgib posted 09-17-2007 10:52 AM ET (US)
My 2002 Jetta and 2005 Jeep Liberty Diesels were both DFI.
Peter posted 09-17-2007 11:16 AM ET (US)
Here is a quick little DFI history read for those that are interested. See members.iinet.net.au/~pauldawson/technology/IAME44-2_DI-hist.pdf .
jimh posted 09-17-2007 11:32 AM ET (US)
Direct injection in a diesel has been used in automobiles as Nick's personal experience demonstrates, but direct injection in a gasoline automobile engine (GDI) is relatively new, and especially so in mainstream American automobiles.
The fact that General Motors is using this in a premier luxury car says to me that they have some faith in the technology.
Tohsgib posted 09-17-2007 11:39 AM ET (US)
In the diesel it almost elimates the smoke. In Gas I bet the MPG increases a good bit and reduces emissions.
GSH posted 09-17-2007 11:57 AM ET (US)
When Volkswagen jumped from multi-point EFI to DI for their Europe-mainstream 1.6 liter motor, the output went up some and the consumption went down some. Good, but no revolution. And the DI (FSI) engine wants 98 octane gas for full preformance.
Also, it now takes longer for a 1.6 liter Golf to get the inside warm in winter. Seems DI means less heat as well...
(some even choose to have gas-burning heaters installed in their cars due to this (no kidding)).
-Seb
Peter posted 09-17-2007 12:31 PM ET (US)
The octane rating requirement for the VW has little to with the direct injection but mostly everything to do with the total engine design. My Evinrude DFI outboards run on 87 octane, about the lowest grade of gasoline offered in the U.S.
I predict that within 10 years, if not sooner, all gasoline automobile motors in the U.S. will be direct fuel injected.
Tadpole posted 09-17-2007 12:38 PM ET (US)
Some are getting caught up in an apples/oranges comparison. ALL diesels are direct injection – ALWAYS have been; they are compression ignition engines. Anywhere from 18 to 1 (and higher) compression super heats combustion chamber, and near top dead center, fuel is injected at more than 2K psi. = combustion/ignition. VERY different than direct injected gasoline engines that still require a spark plug for ignition.
fourdfish posted 09-17-2007 01:14 PM ET (US)
A few here on this web site have been predicting this for several years. Several naysayers here have derided the technology. It will be interesting to see which type of fuel injectors will eventually come out on top! The BRP type injectors have so far been very reliable and one can only
wonder if a similar type as thiers will dominate in the end.
I cannot see why the inside heat should be affected by the switch to DFI.
As the auto industry goes ultimatly so also will the 4 stroke outboard industry. Won't that be something!
GSH posted 09-17-2007 02:24 PM ET (US)
Peter, I would say you are correct. I only mentioned the octane-issue as 98 costs a bit more then 95, so the fuel-cost saving is a little less than the change in mpg. How does you Evinrude preform on 87 octane, by the way?
As for injector, my guess is they will be made by Bosch or some other big company that makes a lot of car industry components. Selva is using car-industry originated DI in their two-stroke L.P.D.F.I. outboards, seems to be working just fine.
And the heat issue, well, I was just thinking it shows how well the enginge is using the energy of the fuel, that's all. I'm sure future DI four-strokes will get up to their prefered running themperatures just fine, even if used in very cold weather.
Tadpole, Mercedes is working on a new engine: check out the F700 Diesotto they rolled out at the Frankfurt Motor show (nice looking car, by the way)!
-Seb
Tohsgib posted 09-17-2007 02:39 PM ET (US)
Europe uses a different octane rating than the USA.
Peter posted 09-17-2007 03:03 PM ET (US)
My motors run just fine on 87 octane.
GSH posted 09-17-2007 04:49 PM ET (US)
Right, sorry!
-Seb
jimh posted 09-17-2007 05:33 PM ET (US)
Here is a more recent press release from General Motors on this new gasoline direct injection (GDI) V6. The 3.6-liter engine ended up being rated at 302-HP. This is [more] power-to-displacement [than the] E-TEC 250-HP [3.3-liter] V6. [Updated this comment to correct an error I made in the displacement of the E-TEC.]
http://media.gm.com/us/cadillac/en/news/press_kits/08sts/ 08_CADILLAC_STS_3.6L%20DI%20V-6.htm
Also noteworthy is the statement that GM "projects that by 2010, one of every six GM vehicles in North America will be equipped with a direct injection engine."
Peter posted 09-17-2007 07:47 PM ET (US)
At up to 1740 PSI of pressure, GM uses a very high pressure DFI system.
aja posted 09-18-2007 08:34 AM ET (US)
I am assuming that all of the automotive DFI applications have been on four-stroke engines. Has there been any talk of two-stroke motors for something other than outboards? It would seem the benefits which are talked about for outboards would carry over well.
GSH posted 09-19-2007 04:48 PM ET (US)
Aja,
If you haven't seen it already and if you're still interested, take a look at:
http://continuouswave.com/ubb/Forum4/HTML/005705.html
-Seb
PS 'Aja' means 'Drive!' in finnish, just FYI... :)

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Author	Topic: GM Brings Direct Injection to V6 Auto Engine
jimh	posted 09-15-2007 12:13 AM ET (US) Since this press release a few months ago, GM has since announced it will use this new engine in the 2008 Cadillac STS. This is the third gasoline direct-injection (GDI) four-stroke engine for General Motors. The two prior engines were in their Ecotec four-cylinder series, motors of much smaller power and displacement. ----- GM Powertrain Unveils 3.6-Liter VVT Engine With Direct Injection Latest offering promises significant horsepower and torque increases, dramatic hydrocarbon reductions, improved fuel economy PONTIAC, Mich. (Mar. 18, 2006) – 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).
Tohsgib	posted 09-17-2007 10:52 AM ET (US) My 2002 Jetta and 2005 Jeep Liberty Diesels were both DFI.
Peter	posted 09-17-2007 11:16 AM ET (US) Here is a quick little DFI history read for those that are interested. See members.iinet.net.au/~pauldawson/technology/IAME44-2_DI-hist.pdf .
jimh	posted 09-17-2007 11:32 AM ET (US) Direct injection in a diesel has been used in automobiles as Nick's personal experience demonstrates, but direct injection in a gasoline automobile engine (GDI) is relatively new, and especially so in mainstream American automobiles. The fact that General Motors is using this in a premier luxury car says to me that they have some faith in the technology.
Tohsgib	posted 09-17-2007 11:39 AM ET (US) In the diesel it almost elimates the smoke. In Gas I bet the MPG increases a good bit and reduces emissions.
GSH	posted 09-17-2007 11:57 AM ET (US) When Volkswagen jumped from multi-point EFI to DI for their Europe-mainstream 1.6 liter motor, the output went up some and the consumption went down some. Good, but no revolution. And the DI (FSI) engine wants 98 octane gas for full preformance. Also, it now takes longer for a 1.6 liter Golf to get the inside warm in winter. Seems DI means less heat as well... (some even choose to have gas-burning heaters installed in their cars due to this (no kidding)). -Seb
Peter	posted 09-17-2007 12:31 PM ET (US) The octane rating requirement for the VW has little to with the direct injection but mostly everything to do with the total engine design. My Evinrude DFI outboards run on 87 octane, about the lowest grade of gasoline offered in the U.S. I predict that within 10 years, if not sooner, all gasoline automobile motors in the U.S. will be direct fuel injected.
Tadpole	posted 09-17-2007 12:38 PM ET (US) Some are getting caught up in an apples/oranges comparison. ALL diesels are direct injection – ALWAYS have been; they are compression ignition engines. Anywhere from 18 to 1 (and higher) compression super heats combustion chamber, and near top dead center, fuel is injected at more than 2K psi. = combustion/ignition. VERY different than direct injected gasoline engines that still require a spark plug for ignition.
fourdfish	posted 09-17-2007 01:14 PM ET (US) A few here on this web site have been predicting this for several years. Several naysayers here have derided the technology. It will be interesting to see which type of fuel injectors will eventually come out on top! The BRP type injectors have so far been very reliable and one can only wonder if a similar type as thiers will dominate in the end. I cannot see why the inside heat should be affected by the switch to DFI. As the auto industry goes ultimatly so also will the 4 stroke outboard industry. Won't that be something!
GSH	posted 09-17-2007 02:24 PM ET (US) Peter, I would say you are correct. I only mentioned the octane-issue as 98 costs a bit more then 95, so the fuel-cost saving is a little less than the change in mpg. How does you Evinrude preform on 87 octane, by the way? As for injector, my guess is they will be made by Bosch or some other big company that makes a lot of car industry components. Selva is using car-industry originated DI in their two-stroke L.P.D.F.I. outboards, seems to be working just fine. And the heat issue, well, I was just thinking it shows how well the enginge is using the energy of the fuel, that's all. I'm sure future DI four-strokes will get up to their prefered running themperatures just fine, even if used in very cold weather. Tadpole, Mercedes is working on a new engine: check out the F700 Diesotto they rolled out at the Frankfurt Motor show (nice looking car, by the way)! -Seb
Tohsgib	posted 09-17-2007 02:39 PM ET (US) Europe uses a different octane rating than the USA.
Peter	posted 09-17-2007 03:03 PM ET (US) My motors run just fine on 87 octane.
GSH	posted 09-17-2007 04:49 PM ET (US) Right, sorry! -Seb
jimh	posted 09-17-2007 05:33 PM ET (US) Here is a more recent press release from General Motors on this new gasoline direct injection (GDI) V6. The 3.6-liter engine ended up being rated at 302-HP. This is [more] power-to-displacement [than the] E-TEC 250-HP [3.3-liter] V6. [Updated this comment to correct an error I made in the displacement of the E-TEC.] http://media.gm.com/us/cadillac/en/news/press_kits/08sts/ 08_CADILLAC_STS_3.6L%20DI%20V-6.htm Also noteworthy is the statement that GM "projects that by 2010, one of every six GM vehicles in North America will be equipped with a direct injection engine."
Peter	posted 09-17-2007 07:47 PM ET (US) At up to 1740 PSI of pressure, GM uses a very high pressure DFI system.
aja	posted 09-18-2007 08:34 AM ET (US) I am assuming that all of the automotive DFI applications have been on four-stroke engines. Has there been any talk of two-stroke motors for something other than outboards? It would seem the benefits which are talked about for outboards would carry over well.
GSH	posted 09-19-2007 04:48 PM ET (US) Aja, If you haven't seen it already and if you're still interested, take a look at: http://continuouswave.com/ubb/Forum4/HTML/005705.html -Seb PS 'Aja' means 'Drive!' in finnish, just FYI... :)