2010 GM 3.0L V-6 VVT DI (LF1)
The 3.0L V-6 VVT DI LF1 is part of GM's growing global family of V-6 engines. They were jointly 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.
These 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, fuel economy, low emissions and first-rate noise, vibration and harshness control, with exclusive durability enhancing features and very low maintenance.
Features of this engine include:
- Direct Injection Technology
- Aluminum engine block and cylinder heads
- Dual overhead cams with four valves per cylinder and silent chain cam drive
- Composite upper intake manifolds
- Integrated exhaust manifolds
- Optimized exhaust manifolds
- Fully isolated composite camshaft covers with added acoustic treatment
Direct Injection Technology
The 3.0L VVT DI uses Direct Injection technology.
Direct Injection differs from the fuel delivery process of a conventional engine by delivering fuel directly into the combustion chamber, where it is mixed with air drawn in to the chamber. Cooling the incoming charge enables a higher compression ratio improving engine efficiency. The combustion process of conventional fuel-injected engines uses air and fuel that are mixed 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 combustion location to improve control.
On the LF1 engine, fuel is introduced directly to the combustion chamber 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 both fuel and air, thus increasing efficiency. DI also permits a higher compression ratio of 11.7. The result is better fuel consumption at part and full throttle. The engine uses conventional spark plugs similar to other high-feature V6 engines.
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 1740 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 cam-driven high-pressure pump works in conjunction with a conventional fuel tank-mounted supply pump.
Direct injection’s high pressure fuel delivery system allows for partially stratified operation, helping to reduce emissions up-to 25%, on cold starts – the time when most engine emissions are typically created.
Aluminum Engine Block and Cylinder Heads
The V-6 VVT's engine block and cylinder heads are cast from A319 aluminum alloy. This aluminum-intensive construction means less weight and greater efficiency than conventional cast-iron engines, and less weight translates to improved vehicle fuel economy. The sand-mold-cast block features strong cast-in iron bore liners, six-bolt main caps, and inter-bay breather vents.
With a compression ratio of 11.7:1 this engine achieves excellent SAE rated specific output of 88.5 HP/liter in the new Cadillac SRX.
Dual Overhead Cams with Four Valves per Cylinder and Silent Cam Drive
Four-valves-per-cylinder inverted tooth chain cam drive contributes to the smoothness and high output of both V-6 engines. Overhead cams are the most direct, efficient means of operating the valves, while four valves per cylinder increase airflow in and out of the engine.
A chain that is powered by the engine's crankshaft drives the dual overhead camshafts over each bank of cylinders. The inverted tooth chain uses a 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. As a result, the noise created by the initial sprocket/chain impact is significantly reduced. The benefit to customers is much quieter and smoother sprocket-to-chain engagement, which enables a smoother and quieter engine.
Intake Manifolds
The upper intake manifold for the 3.0L V-6 is made from composite material and provides mass savings over an aluminum manifold yet the structure is designed to make it quiet.
Engine Control Module (ECM)
The V-6 VVT's nerve network is a new torque-based engine management system, which improves upon previous throttle-based management systems that rely exclusively on the throttle position sensor to govern throttle operation for the electronic throttle control (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.
A single microprocessor manages the following functions:
Cam phasing, which improves performance and efficiency and allows maximum valve overlap at appropriate times, in turn allowing sufficient exhaust gas recirculation without a separate EGR.
Electronic throttle control, with different throttle progressions based on operating conditions and driver demand.
Torque management for traction control.
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.
A limp-home mode for ignition timing. In the event either the crank or cam sensor fails, the ECM 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.
A number of other customer-friendly features, including GM's industry-leading Oil Life System.
The 3.0-liter engine uses the new E39 controller, with 32-bit processing power and 2 megabytes of Burst Flash memory, 128 kilobytes of external RAM and 3 megabytes of internal SRAM.
Integrated Exhaust Manifold
The 3.0L engine utilizes an integrated exhaust manifold, eliminating the need for separate exhaust manifold. The benefits include reducing the mass of the engine for improved fuel economy and faster catalytic converter light off, resulting in reduced emissions.
The 3.0L LF1 VVT engine employs positive crankcase ventilation, and even the PCV valve has been developed to virtually eliminate operational noise. The evaporative emission system performs to a leak-detection standard of .020 inch (about the size of a pin prick).
Fully Isolated Composite Camshaft Covers
The V-6 VVT's cam covers are made of thermoset, glass-filled polyester composite, a material that weighs less than the cast aluminum used on most premium engines and more effectively dampens noise. Required baffles are incorporated into the cover, which is manufactured as an assembly with seals and fasteners attached. In addition, surfaces on the cam covers were shaped to limit the broadcasting of undesirable noise, and the covers use isolating perimeter gaskets, as well as isolating radial lips around the tubes that accommodate the spark plugs. These effectively de-couple the covers from vibration generated in the block and engine during combustion. Acoustic dampening cam covers also have been added for additional NVH improvements.
The 3.0L LF1 VVT engines will be produced in St. Catharines, Ontario, Canada and Ramos Arizpe Mexico.
Maximum Durability, Minimum Maintenance
- The cam drive, cam phasing and valve train components require no scheduled maintenance. The sophisticated cam-chain tensioner, high-quality cam phasing components and hydraulic lash adjusters are designed to ensure optimal valve train performance for the life of the engine with no adjustment.
- Advanced control electronics and a wide range of sensors allow failsafe systems, including ignition operation in the event of timing sensor failures. The control software protects the V-6 VVT from permanent damage in the event of complete coolant loss, and allows the engine to operate at reduced power for a prescribed distance sufficient for the driver to find service.
- The spark plugs have iridium/platinum electrodes and a service life of 100,000 miles without degradation in spark density. The spark plugs are easy to remove because they are located in the center of the cam cover. When the ignition-coil cassettes are removed, the plugs can be reached with a short ratchet extension.
- Extended life Dex-Cool coolant retains its cooling and corrosion-inhibiting properties for 5 years/150,000 miles in normal use.
- The single accessory-drive belt, used primarily for its lapless construction and low-noise operation, is manufactured of EPDM (Ethylene Propylene Diene Monomer) rather than neoprene. EPDM is a rubber material that doesn't breakdown in environments of extreme heat. Replacement is recommended at 100,000 miles.
- With GM's Oil Life System, owners should never pay for an unnecessary oil change again, nor worry that the engine oil has degraded to the point where it has lost its lubricating properties. That, in turn, can significantly reduce the amount of motor oil used, and the amount of used motor oil that must be recycled. The industry-leading Oil Life System calculates oil life based on a number of variables, including engine speed, operating temperature, load or rpm variance and period of operation at any given load and temperature, and then recommends a change when it's actually needed, rather than by some pre-determined mileage interval.
- In extreme operating conditions, such as short periods of operation in very cold temperatures, the Oil Life System might recommend a change in as few as 3,000-3,500 miles. When the engine runs at moderate loads for extended periods with little variance, the system might not recommend an oil change for 15,000 miles.
