Here is Holden’s Alloytec V6 in glorious technical detail.
The global V6 engine is the first V6 engine program to address what Thomas G. Stephens, group vice president, GM Powertrain, says is a vital initiative: to develop world-class engines with fully contemporary features – such as dual overhead cams and variable valve timing – but at a competitive cost structure that allows use of the engines in a global mix of vehicles.
Conceived For Flexibility
From the global V6 engine program start in February 1999, a prime objective was to develop a highly flexible “platform” from which a matrix of possible variants could be developed. The new V6 was designed for true global duty – in addition to Australia’s Commodore, future variants will power a variety of vehicles worldwide.
Several components and features will be common to all global V6 family engines:
• All-aluminium construction
• Dual overhead camshaft (DOHC)
• 4-valve-per-cylinder valvetrain
• Roller-finger follower valvetrain
• Continuously variable cam phasing
• Electronic throttle control (ETC)
• Forged-steel crankshaft
• Piston-cooling oil jets
• Coolant-loss protection software
• GM’s Oil Life System
• 32 bit microprocessor
• Coil-on-plug ignition
“Since the start, the global V6 project team was determined to introduce a V6 engine superior to all in the industry, and in record time,” said Tim Cyrus global V6 chief engineer. “The team tapped GM’s vast technical expertise and developed a V6 with industry leading reliability, flexibility, package size, efficiency and value. This engine was developed by a unique team with talented members from across each of the global GM engine departments and suppliers. We have delivered an engine that can be easily integrated into most platforms, has industry leading NVH and performance with three discrete combustion systems MPFI, SIDI and turbo.”
The global engine family encompasses a range of displacements. In addition to the 3.6L variant that marks the launch of the new engine in production vehicles, there also are 2.8L and 3.2L variants. Engine displacement can be expanded to 3.8L, or as large as 4.0L when the cylinder liners are eliminated in favour of special cylinder bore coatings. Smaller-displacement global engine variants are particularly crucial in world markets where market conditions and competitive issues demand high performance from smaller engines.
Whatever the displacement, the global V6 engine family promises high specific power and torque competitive with the best contemporary V6 engines. The wide range of potential global V6 engine displacements and configurations allows power and torque output perfectly suited to a variety of vehicle, platform, drive configuration or market requirements. The global V6 engine family will effortlessly produce power ranging from approximately 150kW to more than 280kW; torque output will run from 272Nm to in excess of 476Nm.
Aside from the normally aspirated/sequential port fuel injection “foundation” architecture, possible major variants include:
• A spark-ignition direct-injection (SIDI) V6 of either 2.8L or 3.2L displacements. Petrol direct injection is a technology that can produce fuel-economy gains on the order of 10 percent, with no loss of performance. To be most responsive to regulatory and other market considerations, the global V6 engine design has provisions for both stratified-charge (lean-burn) and stoichiometric-charge SIDI architectures. SIDI engines are rapidly expanding in Europe and other regions with high fuel costs.
• Turbocharged engines of either 2.8L or 3.2L, with a variety of power and torque outputs depending on specific content. Turbocharging remains one of the best strategies to increase power and torque without increasing engine size.
From the start, the global V6 engine was designed to power:
• Front-wheel drive (FWD) platforms, in which the engine typically is situated transversely.
• Rear-wheel drive (RWD) vehicles and platforms, where the engine typically is longitudinally mounted.
• All-wheel drive (AWD) architectures, which can dictate either transverse or longitudinal mounting.
The global V6 engine is also suitable for parallel-hybrid application. Parallel hybrid vehicles employ a standard petrol engine and an electric motor or motors, either or both of which can propel the vehicle. Hybrid vehicles offer the prospect of greater fuel economy and can deliver other emissions and fuel-reduction possibilities.
The 3.6L Global V6 engine
The 2004 3.6L global V6 engine is the first variant of the global V6 engine family to go into production. The 3.6L global V6 develops:
• 194kW @ 6,500 rpm
• 339Nm of torque @ 2,500 rpm
The adoption of fully variable valve timing for both intake and exhaust valves – a first for any GM engine – provides outstanding flexibility, fuel economy and emissions-reduction. The four-cam variable valve timing is a key element in the global V6’s control strategy, which imparts the engine with extreme flexibility. For example, 90 percent of the 3.6L V6’s peak torque is available across a remarkably broad operating range: from 1,600 rpm to 5,800 rpm.
“Flexibility was very important,” says Bob Jacques base engine design system engineer. “We insisted on going after high performance and high refinement at the same time.”
Flexibility and Power Optimization
High feature technology is the essence of GM Powertrain’s philosophy behind the global V6 engine family.
The key technologies:
A four-cam continuously variable cam phasing system. This electronically controlled, hydraulically actuated system places a “phaser” on each of the V6’s four camshafts. The cam phasers enable the rotating of each camshaft relative to the crankshaft, eliminating the “fixed” camshaft positions of most engines.
Typically, fixed camshafts dictate valve openings that are a compromise between the desire to have the engine idle smoothly, produce good low-rpm torque, and high-rpm power. The global V6 engine cam phasers, which allow intake cam adjustment through 50 degrees of crankshaft rotation and 50 degrees for exhaust-cam adjustment, permit variability of valve timing to accommodate the often divergent needs for power, driveability, economy and least emissions.
In addition to enhancing power and torque and increasing fuel efficiency, the cam phasing system allowed engineers to eliminate the exhaust gas recirculation (EGR) system typical to most modern engines. By closing exhaust valves later than normal, the cam phasing system forces the desired amount of exhaust gas back into the combustion chamber for more complete burning in the next combustion cycle.
A dual-stage variable intake manifold (VIM). The VIM incorporates a switch in the manifold that changes the plenum volume available for resonance tuning of the inlet flow path. When the VIM switch is shut, the cylinders feed from two separate plenums. In this mode the system boosts cylinder charging in the low to mid speed range. At higher engine speeds, the VIM switch opens and the cylinders all feed from a common larger plenum which boosts cylinder charging at high engine speed.
An electronically controlled throttle (ETC) effectively coordinates the driver’s intentions with the actions of the various control components. ETC eliminates the traditional cable between the accelerator pedal and the throttle body. A throttle position sensor registers the degree to which the driver is depressing the accelerator pedal and translates that movement to a stepper motor that moves the throttle. By eliminating the mechanical connection between the accelerator pedal and the engine, throttle opening can be controlled with advantageous precision.
Micro-hybrid engine control unit ECU. The global V6 ECU represents the latest in engine-management hardware, as well as the software that dictates every aspect of engine operation. The micro-hybrid design embeds all of the necessary electronic circuitry on a four-layer “sandwich” substrate that drastically reduces the size of the control unit. Moreover, the micro-hybrid design imparts a new level of robustness that allows the ECU to be engine-mounted, despite the high levels of vibration the unit experiences from its engine mounting.
The micro-hybrid ECU can withstand mounting temperatures of 110 degrees C and vibration up to 30 g. The engine mounting frees valuable space in the vehicle underbonnet area and eliminates attachment problems at the assembly plant. The 32-bit capacity of the micro-hybrid ECU is the most powerful currently used for automotive application.
Torque-based engine control strategy. Engine output for the driver’s desired throttle opening is determined by the micro-hybrid ECU. The torque-based strategy calculates optimal throttle position, variable intake manifold position, continuously variable cam phasing positions and various other operational inputs and then translates that information into an ideal throttle position. The torque-based engine control strategy is superior to early electronically controlled throttle-based engine-management systems that relied only on the throttle position sensor to govern throttle opening.
Returnless fuel system. The returnless fuel system architecture eliminates fuel system recirculation thereby reducing fuel heating and evaporative emissions. A variable pressure option is used on the turbo engines. A pressure sensor located in the fuel rail provides feedback to a variable pressure fuel pump in the fuel tank. Fuel control, emissions, and driveability are significantly improved by increasing the operating fuel pressure at higher engine loads to deliver the required fuel flow but maintain precise fuel control at lower engine loads with injectors sized for optimal refinement.
The global V6 engine family will be assembled for all global applications at GM Powertrain facilities in St. Catharines, Ontario, Canada and Port Melbourne, Victoria, Australia.
The Inside Story
The global V6 engine family encompasses an aluminium-intensive basic design, with all major pieces constructed of aluminium. The deep-skirt cylinder block is of precision sand cast 319 aluminium with cast-in-place iron cylinder liners. The cylinder head is a semi-permanent mould 319 aluminium casting. The upper intake manifold is composed of 319 sand-cast aluminium, while the lower manifold is made of 356-T6 aluminium.
The cylinder block incorporates six-bolt main-bearing journals and modular-type oil filter/cooler mounting point to facilitate attachment of the correct oil filter assembly. Cast in inter-bay breather vents in the engine block reduce windage losses at high speed.
Global V6 cylinder heads utilize convergent exhaust ports for maximum flow and thermal conservation, lower emissions and reduced engine mass. Multi-layer stainless steel head gaskets offer maximum durability.
The 60-degree cylinder bank angle is ideal for a V-6 configuration, and the global V6 architecture supports multiple displacement options for maximum flexibility.
Strength, durability and reliability were key design points for global V6 major internal components. Weight-, NVH- and durability-optimizing materials were specified wherever possible.
The micro-alloyed 1038V forged steel crankshaft provides maximum strength and stiffness. Sinterforged steel connecting rods offer maximum durability, while aluminium pistons with fully floating 24-mm gudgeon pins and polymer-coated skirts allow tighter piston clearance for quiet cold starts.
The crankshaft sprocket employs durable, moulded-rubber “cushion rings” that absorb the noise of the camshaft drive chain engaging the sprocket teeth. A dual-mass flywheel with torsional damper eliminates gear rattle and driveline shudder in manual transmission applications.
The engine employs a Teflon crankshaft oil seal, common across GM powertrains.
The outstanding power and efficiency of the global V6 can be directly attributed to the continuously variable cam phasing system, which incorporates an individual camshaft phaser for each of the engine’s four camshafts. By rotating the camshaft relative to crankshaft angle, valve timing is infinitely variable over a 50-degree range of crankshaft rotation. This provides greater flexibility and control over engine breathing and translates to high specific power, excellent drivability and low emissions.
Cam phasing system components are designed to deliver maximum durability and outstanding NVH properties. In addition to the orifice-feed primary chain tensioner with startup reservoir and backlash control, a two-stage roller-chain camshaft drive enhances durability and reduces noise.
The global V6 engine family incorporates the GM Powertrain customary OHC valvetrain design: four valves per cylinder and dual overhead camshafts with roller-finger rocker arms. The design provides maximum efficiency and power-producing potential while simultaneously reducing friction as much as possible. The low mass DOHC roller-follower valvetrain configuration operates with very low frictional losses to enhance fuel efficiency. Hydraulic lash adjusters and a three-stage roller chain cam drive minimize scheduled service on these components.
Lubrication is critical to any engine, and the global V6 lubrication system is designed to assure maximum mechanical protection and reliability combined with low maintenance. In a nod to the engine’s high specific output and potential for future high-performance variants, special features such as pressure-actuated piston-cooling oil jets are specified, to provide extra cooling and control piston temperatures under the most high-stress conditions.
The engine’s baffled oil pan and windage tray reduce friction losses at high speed and ensure oil supply under all operating conditions. The structural aluminium oil pan employs a full-circle bolt pattern for transmission attachment, maximizing powertrain stiffness for enhanced quiet operation. A crankshaft driven gerotor oil pump with internal pressure-relief valve ensures reliable engine priming for maximum reliability, as well as quiet operation.
A six-quart capacity oil sump enables extended oil change intervals, while the sophisticated GM Oil Life System maximizes individual change requirements based on driving habits.
The top-access, cartridge style oil filter promotes ease of maintenance.
The Global V6 induction and exhaust systems incorporate state-of-the-art design, combining a two-stage variable intake manifold (VIM) with electronic throttle control (ETC) to allow the utmost response to the driver’s request for power.
Often called “drive by wire,” ETC delivers maximum performance and precision coordination with other engine- and vehicle-related electronic control systems. The equal length centre feed dual plenum intake manifold achieves optimal flow performance while reducing irritating noises.
Convergent exhaust ports are designed to conserve heat for lower emissions and reduce engine mass. The exhaust manifolds are cast nodular iron with laminated heat shields. The secondary throat cuts in the inlet ports improve airflow into the cylinder and help eliminate harsh combustion noise, common to some high-performance engines.
An internal fuel-rail damper integrated into the fuel rail suppresses pressure fluctuation noises in the fuel system caused by injector operation.
The global V6 engine control unit, or ECU, is the most powerful and sophisticated currently available for automotive use. Its high capacity assures that each of the global V6 electronically controlled subsystems coordinates with the highest efficiency. The engine-mounted, 32-bit Bosch Motronic ME9 micro-hybrid ECU design was specified to deliver industry-leading performance in a remarkably small, durable unit. The ECU houses software that dictates every aspect of engine operation, from individual cylinder-adaptive knock-control sensing to torque-based engine control.
The global V6 engine family features a coil-on-plug ignition system, delivering maximum energy spark and the most precise possible timing. The increased efficiency of the system contributes to lower emissions and, with fewer parts and no wires, improves quality, reliability, and dependability. Extended-life spark plugs have dual-platinum electrodes and service life of 160,000km.
A cam sensor, which monitors the camshaft position, and a crankshaft position sensor are used to manage spark timing. This dual measurement system ensures extremely accurate timing throughout the life of the engine and provides a backup in the event that one of the two sensors fails.
The global V6 engine family’s extremely precise emissions control comes from coordination of the engine’s advanced control systems. The continuously variable cam phasing system, variable intake manifold, electronically controlled throttle and other components combine to reduce engine emissions to the greatest degree possible.
Intake and exhaust camshaft phasing provides more complete burning of exhaust gases, eliminating the need for exhaust gas recirculation. Dual close-coupled catalytic converters enable fast catalyst “lightoff,” reducing emissions below LEV2 Tier II standards.
Electronic throttle control (ETC) allows more precise control of throttle opening by eliminating the mechanical link between the accelerator pedal and the engine.
The all-new global V6 engines also employ positive crankcase ventilation with NVH optimized PCV valves, evaporative emission recovery systems and wide-range oxygen sensors.
A high efficiency water pump and computer-optimized coolant jacket allow efficient coolant distribution. The inlet side thermostat and low volume coolant jackets provide rapid, consistent, warm-up behaviour, channelling heat to the passenger compartment more quickly in winter.
Extended-life coolant requires minimal service and less frequent changes.
The global V6 cooling system, as in some other GM Powertrain engines, incorporates unique coolant-loss protection software. This feature enables the engine to operate at reduced power output when there has been a total loss of engine coolant, allowing the driver to reach a secure location.
Curved injection-moulded thermoset composite camshaft covers with vibration-isolated perimeter gaskets and sparkplug radial lip seals and a contoured aluminium front cover attenuate undesirable vibrations and resonant periods. Mechanically attached multi-layer steel damping panels inside the cover are designed to provide additional damping to further reduce noise.
2004 3.6L Global V6 Engine (LY7) Specifications
Configuration: 3.6L 60-degree DOHC V-6
Peak Power (SAE net): Estimated 190kW @ 6,500 rpm
Peak Torque: 339 Nm @ 2,800 rpm;
(90% of peak produced from 1,600 rpm to 5,800 rpm)
Displacement (cc): 3,564
Bore x Stroke: 94 mm x 85.6 mm
Valvetrain: Dual overhead camshaft
Roller-finger followers valvetrain
Hydraulic lash adjusters
Four-cam continuously variable cam phasing
Two-stage roller-chain camshaft drive
Variable Cam Timing: Intake: 132 degrees ATDC initial timing
50 crankshaft degrees advance authority
Exhaust: 111 degrees BTDC initial timing
50 crankshaft degrees retard authority
Compression Ratio: 10.2:1
Bore Centers: 103 mm
Firing Order: 1-2-3-4-5-6
Fuel Shutoff: 6,700 rpm
Engine Idle Speed: 600 rpm
Fuel System: Sequential port fuel injection (returnless)
Engine Management: Torque-based; Bosch Motronic ME 9 32-bit micro-hybrid controller
Intake Manifold: Dual-plenum, equal-length with 2-position variable volume control (resonance tuned)
Throttle: 68-mm single bore; electronic control (ETC)
Ignition: Individual coil-on-plug; individual cylinder knock control
Fuel Requirement: Premium fuel recommended
Emissions Controls: Dual close-coupled catalytic converters (1.15L ultra-thinwall ceramic)
Positive crankcase ventilation (PCV)
Intake- and exhaust-cam phasers (EGR)
Evaporative emissions system
Assembly Sites: St. Catharines, Ontario, Canada
Port Melbourne, Victoria, Australia
Block Material: Aluminium, precision sand-cast 319 with cast-in-place iron liners
Cylinder Head Material: Aluminium, semi-permanent mould 319
Intake Manifold: Upper: Aluminium, sand-cast 319
Lower: Aluminium, 356-T6
Exhaust Manifold: High-silicon moly cast iron
Camshaft Covers: Injection compression thermoset composite; vibration isolated
Front Cover: Diecast 380 aluminium; internal multilayer damping panels
Crankshaft: Forged steel
Connecting Rods: Sinterforged steel
Pistons: Aluminium, polymer-coated skirts, full-floating wristpins
Main Bearing Caps: 6 bolt caps, copper-infiltrated sintered steel
Oil Pan: Structural diecast aluminium, steel windage and baffle plates
Additional features: Pressure-actuated piston-cooling oil jets
Extended-life sparkplugs, coolant, accessory belts
Cartridge-style, top-access oil filter
Wide-range oxygen sensors