Infiniti builds petrol engine with diesel efficiency
Nissan’s premium sub brand Infiniti has developed the first production-ready Variable Compression Turbocharged (VC-T) four-cylinder petrol engine. This revolutionary engine is supposed to offer both the torque and the efficiency of a diesel engine, without the emissions. At the same time, the new technology makes assistance from an electric motor (hybridisation) obsolete.
The brand said the technology took more than 20 years to develop. It allows the engine to change its compression ratio – the number of times the volume of the cylinder is compressed between the moment the piston is at the bottom of the stroke and the moment it reaches the top – to suit the driving conditions.
An actuator allows the piston stroke to vary, meaning that the compression ratio can be raised to 14:1 to offer high efficiency at low loads, and lowered to 8:1 for high performance at high loads. Turbocharged petrol engines typically have low compression ratios to compensate for the fact that at high loads, a lot of heat and pressure is generated by the air from the turbocharger. The higher the compression ratio, the higher the temperature and the risk for knock – the unwanted pre-detonation of fuel.
The first model to benefit from the new powertrain is the 2018 Infiniti QX50, an Audi Q5/BMW X3/Jaguar F-Pace/Mercedes GLC competitor. The engine can be seen at the 2016 Paris Motor Show, which starts September 29.
Picture copyright: Nissan, 2016
