Car manufacturers of today are pushing the limits of textbooks and principles to a whole new realm; shattering barriers as they were never there and making our cars more stronger; more smarter; and efficient, Infiniti just pushed this race a bit far by introducing their VC-Turbo Engines at Paris Motor Show.
Variable compression ratio, a tried and tested technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. Designed to increase fuel efficiency while under varying loads, the first VCR engine was built and tested by Harry Ricardo in the 1920s. This work led to him devising the octane rating system that is still in use today. These variable compression engines have existed for decades but only in laboratories for the purposes of studying the combustion processes.
Earlier variable compression engines have been highly desirable but technically unobtainable for production vehicles due to the mechanical complexity and difficulty of controlling all of the parameters. At 2018 Paris Motor Show, INFINITI the luxury subdivision of Nissan, gave attendees a glimpse into the future revealing ground-breaking new engine technology of variable compression ratios.
INFINITI’s new VC-Turbo (Variable Compression Turbo) is the world’s first production-ready to use variable compression ratio engine. Promising to be one of the most advanced internal combustion engines ever built, VC-Turbo technology combines the power of a high-performance 2.0-liter turbo gasoline engine with the torque and efficiency of an advanced diesel powertrain – without the equivalent emissions.
The VC-Turbo changes its compression ratio seamlessly with an advanced multi-link system, continuously raising or lowering the pistons’ reach to transform compression ratio – offering both power and efficiency, on user’s demand.
Theoretically, a high compression ratio gives greater efficiency, as it is able to churn out maximum energy from a given fuel chemistry but in certain applications poses the risk of premature combustion (‘knocking’). On the other hand, a low compression ratio allows for greater power and torque, avoids knocking but demands a higher fuel supply. In operation, the QX50’s VC-Turbo engine can offer any compression ratio between 8:1 (for high performance) and 14:1 (for high efficiency). Deploying smart power for greater control, the empowering engine exemplifies INFINITI’s driver-centric approach.
The blend of performance and efficiency represents a compelling alternative to diesel, challenging the notion that only hybrid and diesel powertrains are capable of delivering high torque and efficiency. The engine delivers a staggering 268 HP (200 kW) @ 5,600 RPM and a humongous torque of 280 lb-ft (380 Nm) @ 1,600 – 4,800 rpm. The VC-Turbo’s specific power output is higher than many competing turbocharged gasoline engines and even comes close to the performance of some masculine V-6 gasoline engines. The unit’s single-scroll turbo ensures immediate accelerator responses on demand diminishing the long-faced problem of turbo lag faced by Turbocharged engines.
Equipped with the VC-Turbo engine, the QX50 is comparatively efficient, delivering gasoline fuel economy of 27 mpg (US combined, front-wheel drive; 26 mpg all-wheel drive). In front-wheel drive specification, this offers a 35% improvement in fuel efficiency over the V6 gasoline engine in the previous QX50, while the new all-wheel-drive model’s 26 mpg represents a 30% improvement.
This new engine will be incorporated in new Infiniti QX50 which is a Compact luxury crossover SUV. The first generation QX50 was a minor model update of the Infiniti EX and this second generation QX50 which has this new VC-Turbo engine will be available from the end of this year.