2010 GM 2.8L V-6 VVT Turbo (LAU)
2010 Model Year Summary
- Twin-Scroll
turbocharger
- Dual
Continues Variable Cam Phasing
- Unique
double-wall exhaust manifolds
-
Engine-mounted oil cooler
- Robust
356T-6 aluminum cylinder heads
-
Air-to-air intercooler
SAE Certified Power = 300 hp ( 224 kW ) @ 5500 rpm
2010 Cadillac SRX =
295 lb-ft ( 400 Nm ) @ 2000 – 4500 rpm
New turbocharged variant for
global V-6 family
New turbo
variant of GM's sophisticated global V-6 engine family. Versus MY'08 the new
2.8L V-6 Turbo features a larger high-efficiency compressor, additional exhaust
cam phaser and a new engine control unit. It also features a higher specific
output as well as a broad torque band to deliver the performance of a
larger-displacement engine.
Twin-scroll turbocharger
The
turbocharger features a unique Twin Scroll design incorporated in a high
temperature resistant cast Stainless Steel alloy. The dual inlet chamber from
the exhaust manifolds on each cylinder bank emphasis performance in faster
throttle response and smooth power increase. A single compressor feeds
pressurized air into the fixed volume intake manifold through a high efficient
Air-To-Air Charge air cooler to further increase air density and engine
performance.
Dual continuous variable cam
phasing
4 hydraulic vane type phasers are
used to rotate the intake and exhaust camshafts relative to the cam drive
sprockets. The vane phaser is actuated by hydraulic pressure from engine oil,
and managed by a solenoid that controls oil pressure on the phaser. The phasers
adjust the cam timing quickly and seamlessly for optimum performance ,
drivability and fuel economy.
Unique double-wall exhaust
manifolds
Special
exhaust manifolds made of two steel pipes, one inside the other, lead to the
double-duct turbocharger housing. There is an air gap between the inner and
outer pipes, to insulate heat and noise.
Engine-mounted oil cooler
An
engine-mounted oil cooler is attached to the left side of the engine block to
promote the longevity of the oil.
Robust 356T- 6 aluminum cylinder
heads
The
cylinder heads are constructed of stronger 356T-6 aluminum to ensure durability
with the additional heat generated by the forced induction of the turbocharger.
Air-to-air intercooler
To lower
the temperature and increase the density of the intake air, an air-to-air
intercooler is incorporated into the intake air system.
Overview
The 2.8L
V-6 Turbo was introduced for the 2006 model year simultaneously in North
America for the Saab 9-3 and in Europe for the Saab 9-3 and Opel Vectra. The
3.6L V-6 VVT was the first engine in GM's sophisticated, global V-6 engine
family and debuted in 2004. A naturally aspirated 2.8L was added for 2005. The
global V-6 architecture was jointly developed by GM technical centers in
Australia, Germany, North America and Sweden. The engine's design is based on
the philosophy that a true family of global engines provides the best value and
performance for the customer and the best return on investment for General
Motors. The engines apply the most advanced automotive engine technology
available, from state-of-the-art casting processes to full four-cam phasing to
ultra-fast data processing and torque-based engine management.
Each delivers a market-leading
balance of good specific output, high torque over a broad rpm band, good fuel
economy, low emissions and first-rate noise, vibration and harshness control, with
exclusive durability enhancing features and very low maintenance.
The
turbocharged 2.8L has a slightly reduced compression ratio of 9.5:1. The
sand-mold-cast block features strong cast-in iron bore liners, six-bolt main
caps, and inter-bay breather vents.
Like the
earlier Global V-6 engines, double overhead cams, four-valves-per-cylinder
heads with silent chain valvetrain continue to contribute to the V-6 Turbo's
smoothness and high output. The silent chain drive operates with less noise due
to an inverted tooth design that spreads out the period of engagement between
the sprocket and chain. By lengthening the period of contact between the
sprocket and chain, the force of the initial impact between the two is reduced
because it is spread out over a longer time period. Therefore, the noise
created by the initial sprocket/chain impact is significantly reduced. The
result is much quieter and smoother sprocket-to-chain engagement, and that
makes for a smoother and quieter engine.
The 2.8L
V-6 Turbo employs cam phasing for variable valve timing to change the timing of
intake and exhaust 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 drivability. The variable cam phasing also makes it
possible to match a slightly larger turbo then a conventional non phased
engine, this also emphasis the fantastic performance bandwidth of this engine.
The V-6
Turbo uses hydraulic vane-type phasers to rotate the intake/exhaust camshafts
relative to the cam-drive sprockets. The variable valve timing system was
developed for maximum durability and outstanding noise, vibration and harshness
control. It is virtually impervious to particles or contaminants in the engine
oil and minimizes the chance that the phasers can stick, even in the most
demanding operating conditions. The phasers adjust cam timing quickly and
seamlessly for optimum performance, driveability and fuel economy.
Aluminum-intensive
construction extends to the V-6 Turbo's pistons, which are cast aluminum and
feature full floating wristpins. Finally, the global V-6 engine family was
developed with pressure-actuated oil squirters in all applications. Three jet
assemblies in the block each hold a pair of oil-squirting jets that drench the
underside of each piston and the surrounding cylinder wall with an extra layer
of cooling, friction-reducing oil. The jets are activated when oil pressure
reaches a prescribed level. They reduce piston temperature, which in turn
allows the engine to produce more power without reducing long-term durability.
Moreover, the extra layer of oil on the cylinder walls and piston skirts
further dampens noise emanating from the pistons, meaning quieter operation.
The V-6 Turbo's durability enhancing
features included a polymer coating applied to the piston skirts. This
high-tech coating was developed to withstand the heat and friction generated by
piston movement in the cylinder, and it allows tighter piston-to-bore
clearances without bore scuffing. The polymer coating extends the benefits of
the floating-pin piston and rod assembly and further reduces noise generated by
the piston's movement within the cylinder. The coating also helps limit bore
scuffing, or abrasion of the cylinder wall over time from the piston's up-down
motion. The net result is a quieter, more durable engine.
The
strength of a forged steel crankshaft ensures the durability required of high
output variants of the global V-6 engine family, and it adds an extra level of
robustness in the 2.8L Turbo engine. The V-6 Turbo's connecting rods are
manufactured of sinter-forged steel. Sinter-forging is considerably more
expensive than conventional casting or wrought forging. Yet because parts are
manufactured with much greater precision, they require less machining, and both
machine tooling costs and manufacturing time are reduced. Overall assembly
efficiency and quality increases.
The 2.8L V-6 Turbo's sequential fuel
injection manages fuel pressure at the injectors and eliminates a fuel return
line from the engine to the fuel tank. This "returnless'' injection also
known as a demand system improves performance and greatly reduces emissions. It
is one of the most efficient fuel-delivery systems in production and, true to
the V-6 VVT global development philosophy, provides the foundation for several
fuel-injection variants that can be tailored to market demands or legislative
mandates without extensive re-engineering. The vehicle fuel tank has a variable
pressure supply pump which regulates fuel pressure between 3 to 5.5 bar which
improves the dynamic range of the fuel system this fuel pressure is regulated by
a fuel pressure sensor on the fuel rail
All of the global V-6's fuel
delivery components, from the fuel pump to the delivery line to the injectors,
have been developed to minimize operational noise. The fuel rail is fitted with
an internal fuel pressure damper, which virtually eliminates harsh pressure
pulses.
Electronic
"drive-by-wire" throttle eliminates a mechanical link between the
accelerator pedal and throttle plate. The global V-6 has no throttle cable;
instead, a potentiometer at the pedal measures pedal angle and sends a signal
to the ECM; the ECM then directs an electric motor to open the throttle at the
appropriate rate and angle. Electronic Throttle Control (ETC) is integrated
with the ECM, which uses data from multiple sources, including the transmission's
shift patterns and traction at the drive wheels, in determining how far to open
the throttle. With this data, the V-6 effectively anticipates the driver's
demands, whether it's a slow-speed parking maneuver or wide-open throttle
operation on the open road, and responds appropriately. ETC delivers
outstanding throttle response and greater reliability than a mechanical
connection. Cruise control electronics are integrated in the throttle,
reducing
the amount of wiring required, further improving reliability and simplifying
engine assembly.
The global V-6's coil-on-plug
ignition delivers the highest energy spark and most precise timing available.
The increased efficiency of coil-on-plug spark contributes to lower emissions.
The system has no high-tension spark plug wires and fewer parts than conventional
ignitions, improving durability, allowing more efficient engine assembly and
enhancing build quality.
Spark
timing is managed with both a cam sensor that reads a reluctor wheel on the cam
phaser and a sensor that reads a reluctor wheel pressed onto the crankshaft.
This dual-measurement system ensures extremely accurate timing for the life of
the engine. Moreover, it provides an effective back-up system in the event of a
sensor failure.
On the
global V-6, a single microprocessor manages the following functions and more:
Cam phasing for variable valve timing, which improves performance and
efficiency; electronic throttle control, with different throttle progressions
based on operating conditions and driver demand; torque management for traction
control and all-wheel drive; the returnless fuel injection system with
injection and spark-timing adjustments for various grades of fuel; the ignition
system and knock sensors, which push spark advance to the limit of detonation
(hard engine knocking) without crossing over, maximizing fuel economy;
fast-heating oxygen sensors with pulse-width modulation, which varies
electrical current like a rheostat rather than an on-off switch and allows
lower cold-start emissions; and the variable intake manifold. The ECM provides
a limp-home mode for ignition timing, in the event either the crank or cam
sensor fails. It will continue to control timing based on data from the
functioning sensor, and advise the driver with a warning light. It also
provides coolant loss protection, which allows the V-6 VVT to operate safely at
reduced power, even after there has been a total loss of engine coolant, so the
driver can reach a secure location. Additionally, the ECM allows a number of
other customer-friendly features, including GM's industry-leading Oil Life
System
The 2.8L V-6 Turbo also uses a
torque-based control strategy, which improves upon previous throttle-based
management systems that rely exclusively on the throttle position sensor to
govern throttle operation for the ETC. The torque-based strategy calculates
optimal throttle position, the position of the intake plenum plate, cam phasing
positions and other operational parameters and translates that data into an
ideal throttle position and engine output, based on the driver's positioning of
the gas pedal.
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