Motorshows have always been about cars or bikes but not much about engines. However, at the Paris Motorshow Infiniti brought us a glimpse of one the future of engines. Now, if you think practically, varying an engine’s compression ratio has always been a target for most manufacturers. Squeezing the air (and sometimes the fuel too) is extremely crucial if you consider making the engine efficient. So, varying this ability (compression ratio) is understandably an arduous task but Infiniti seems to have cracked the code with its new Variable Compression-Turbocharged (VC-T) engine which is code named MR20 DDT. You might think that there’s the Atkinson cycle engine which is used widely and this one too separates the effective compression ratio from the expansion ratio, all thanks to variable intake-valve timing. But the need of the hour is to curb fuel consumption and push the mileage figure higher and this is where the Infiniti MR20 DDT might make a world of difference. The VC-T is a boosted 2.0-litre four-cylinder engine which has taken two decades of research and 300 patents to see the light of day. The engine will power unspecified Infiniti models beginning in 2018. The people at Infiniti promise that it is the most advanced internal combustion engines ever created. The VC-Turbo technology combines the power of a high-performance 2.0-litre turbo gasoline engine with the torque and efficiency of an advanced diesel powertrain – without the equivalent emissions. The VC-T has four multilink mechanisms inside its crankcase and these offer computer control over each cylinder’s compression ratio. The multi-link is a diamond-shaped component that replaces the connecting rod’s big end. When the electronically driven mechanism rotates, it moves everything including the actuator arm, control shaft, lower link, as also the multilink which then helps in varying the piston’s stroke within the cylinder bore. Infiniti claims that the VC-T is capable of providing any desired compression ratio between 8.0:1 (for performance) and 14.0:1 (for high efficiency). The compression ratio of 14.0:1 helps in maximizing fuel efficiency during light-throttle cruising. We have to assert here that the 2.0-litre turbocharged 4 cylinder engines with fixed-compression ratio are widely used and we see this engine in cars from the Mercedes-Benz stable (CLA, GLA et al) and these generally have a compression ratio in the range of 9.5:1-to-11.0:1. Compare this figure to the Infiniti engine and you’ll understand that the VC-T’s number is higher on the high end and lower on the low end. The VC-T comes with port and direct fuel-injection systems but in addition to this it also gets an individual cylinder ignition timing, variable intake- and exhaust-valve timing, and electronic boost control. Infiniti has managed to save some weight too by integrating the exhaust manifold with the cylinder head, and by making the block and head of aluminum. This will also make sure that the cost remains on the lower side too. With a development target power output of approximately 268 hp and 390 Nm torque, the VC-Turbo engine will be comparable to certain six-cylinder gasoline powertrains for performance, while significantly outperforming them in efficiency. The four-cylinder VC-Turbo engine achieves lower levels of noise and vibration than conventional internal combustion engines, particularly diesel, and is lighter and more compact than V6 units with comparable power outputs. Roland Krueger, President of Infiniti Motor Company, commented: “The pioneering new VC-Turbo powertrain represents a leap forward for engine development. Vehicle engineers believe the breakthrough in internal combustion technology would come from mastering the variable compression ratio. Infiniti will be the first to bring this technology to the market in 2018. This new generation of powertrains will help our global growth and expansion of the Infiniti product portfolio.” Mind you this breakthrough will not just help Infiniti but Nissan too and we hope to see it put to good use from 2018.
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