Infiniti introducing new advanced 3.0L V6 twin-turbo engines for 2016 Q50; up to 6.7% improvement in fuel efficiency
Infiniti has developed a new advanced compact and lightweight 3.0-liter V6 twin-turbo engine which is making its debut in a 400 hp configuration for the new 2016 Infiniti Q50, which will premiere at the North American International Auto Show in January.
Key engine features include a compact, lightweight aluminum-alloy engine block and cylinder heads; Gasoline Direct Injection (DIG) system; optimized turbine blade design; turbine speed sensor; electronic wastegate actuator; water-cooled engine charging; e-motor valve timing control; and an integrated exhaust manifold.
|2016 Infiniti Q50. Click to enlarge.|
In addition to the 400-horsepower configuration, a 300-horsepower version will be available across the Q50 lineup in late spring. The new VR-series engine family replaces the award-winning Infiniti 3.7-liter VQ-series V6.
(The third new powerplant for the 2016 Q50 is a 208-horsepower 2.0-liter turbo inline 4-cylinder engine developed in conjunction with Daimler and produced at Infiniti’s new engine facility in Decherd, Tenn. Infiniti will offer a start-stop system with the 2.0L, four-cylinder turbo. Also available in late winter 2016 is the Q50 Hybrid, featuring a 3.5-liter gasoline-electric hybrid system with a net 360 horsepower rating. The hybrid powertrain is unchanged.)
The all-new 3.0-liter V6 twin-turbo engine was developed to deliver optimal power and torque, alongside greater fuel efficiency. The high-output version of the power unit delivers 400 horsepower (298 kW) at 6,400 rpm and 350 lb-ft (475 N·m) maximum torque at 1,600-5,200 rpm. The standard output version produces 300 horsepower (224 kW) at 6,400 rpm and 295 lb-ft (400 N·m) torque at 1,600-5,200 rpm.
While the 300 hp version is fitted with a single intercooler pump, the 400 hp engine uses two for more effective management of heat when under operating at higher loads. In addition, for the 400 hp variant an optical turbo speed sensor gives a 30% power boost to the turbo system by allowing the blades to spin faster.
These outputs have been achieved while ensuring an expected improvement in fuel efficiency of up to 6.7%, representing a high power-to-efficiency ratio for the 400 hp power unit. This power-to-efficiency performance was made possible thanks to a combination of newly developed powertrain features.
An advanced new twin-turbo system contributes to the smooth and immediate power delivery while promoting gains in efficiency. The combination of a new turbine speed sensor and an optimized turbine blade design realize greater performance with more immediate response.
The turbine speed sensor allows a 10% increase in turbine speeds, enabling the turbocharger to revolve at up to 220,000 rpm at steady condition and 240,000 rpm at transient condition—higher than ever before for a V6 power unit. With greater capacity for faster revolutions, the twin turbochargers boost the higher-powered version of the engine to deliver higher power and torque. The turbo speed sensor on the 400 hp version allows for up to 30% more power output.
The engineers have developed a water-cooled intercooler system to further improve performance and efficiency. The system rapidly cools air as it enters the twin-turbo system, reducing turbo lag and allowing for more immediate acceleration. The secondary result is a cooling system which is more compact—meaning a shorter flow path for air entering the turbocharger to enable quicker engine responses.
A new electronic wastegate actuator allows closer control of exhaust gas flow away from the turbocharger, restricting the amount of exhaust gas flowing through the unit to improve overall engine efficiency.
Advanced valve timing control incorporating a new electric motor mounted to the valve timing system delivers quicker reactions to driver inputs. Along with improved response, more immediate valve timing also helps the engine operate more efficiently, precisely controlling fuel and air quantities entering the combustion chamber.
A new high-pressure direct injection gasoline (DIG) system, introduced for the first time, allows for precise control of fuel injection into the combustion chamber depending on throttle position and current engine speed. DIG contributes significantly to making the new engine the cleanest and most efficient V6 that Infiniti has ever offered.
Lower weight, greater mechanical efficiency, more engaging drive. The core structure of the 3.0-liter V6 twin-turbo engine weighs 194.8 kg (429.5 lbs)—14.1 kg (39.1 lbs) less than the engine it replaces. The new turbocharger and advanced intercooler (or CAC) system componentry adds just an extra 25.8 kg (56.9 lbs), for 220.6 kg (486.3 lbs) in total.
The all-new power unit is 19% (0.7 of a liter) smaller in capacity than earlier V6 engines offered by Infiniti. It builds on the company’s legacy of embracing new engineering solutions and technologies. Just as these earlier engines were respected for their lightweight aluminum construction and low mechanical friction, the 3.0-liter V6 twin-turbo engine follows its performance-oriented predecessors with a more compact and lightweight design, while maintaining a performance focus.
Chief among the new weight-saving elements is the adoption of spray bore coating for the engine block and integrated exhaust manifold for cylinder heads. Not only does this make the engine lighter, but this also aids cooling as heat can dissipate more effectively through the aluminum alloy bore wall, a process boosted further by its physical design, which encourages faster engine heat management.
The lower weight throughout the engine contributes to greater mechanical efficiency, with lower inertia from its lightweight aluminum components, while this added efficiency adds to the drivability and overall performance of the V6 engine.
The new cylinder-bore coating process further boosts mechanical efficiency. The new low-friction mirror bore coating technology allows the pistons to move more freely in the cylinders by reducing levels of mechanical friction by 40% compared to the previous V6 engines. This mirror bore coating process involves cylinder walls getting treated with a thermal arc spray coating after which the coating is hardened. The mirror-smooth cylinder wall reduces piston friction and boosts performance.
The mirror bore coating process saves the 3.0-liter V6 twin-turbo engine 1.7 kg (3.8 lbs) in weight, when compared to previous V6 engines, owing to the hardened tolerance that the spray system gives to lighter metals.
One of the most significant features in the all-new 3.0-liter V6 twin-turbo engine is the adoption of a new integrated exhaust manifold, built into the cylinder head, enabling engineers to position the catalytic converter closer to the exhaust point. This results in a shorter flow path for the hot exhaust gases, allowing the catalytic converter to heat up almost instantly—twice as fast as previous V6 engines—and reducing emissions from a cold start.
Moving the catalytic converter closer to the exhaust point saves weight by making the engine more compact than before. This design accounts for a 5.3 kg (11.7 lbs) reduction in weight.
The new aluminum engine block has been constructed as a square engine, with equal cylinder bore and stroke dimensions (86.0 x 86.0mm). As a result, the 3.0-liter V6 twin-turbo engine combines low mechanical friction and fast-revving response. Power and torque are accessed across a broader spread of mid-range engine speeds, in which drivers typically spend most of their time.
The all-new 3.0-liter twin-turbo V6 engine is due to enter production during 2016 and will be manufactured at the powertrain plant in Iwaki, Fukushima, Japan.