|The 1.6-liter U2 diesel. Click to enlarge.|
The Powertrain R&D Center of Hyundai Motor Company has completed development of a new, more fuel efficient and cleaner diesel engine for compact passenger vehicles (C-segment and below). The 1.6-liter (1,582cc) U2 is an inline four-cylinder engine which utilizes a second-generation common rail diesel injection system and supports a fuel consumption rating of 4.7 L/100km (50 mpg US).
The first car to have the U2 engine installed will be the successor model of the Getz, the i20 sub-compact. The i20, due to be launched in Europe towards the end of 2008, will be produced at Hyundai Motor Co.’s Indian subsidiary in Chennai.
The engine features technologies such as a variable geometry turbocharger, a variable swirl control system and an electronically controlled exhaust gas recirculation (EGR) cooling system. With fuel consumption of 4.7 L/100km, the US has CO2 emissions of 125 g/km. The U2 is Euro4 compliant. An optional particulate filter reduces particulate matter to Euro 5 standards which take effect next year.
The engine uses a new Bosch 1,600 bar CRDi common rail injection system which is capable of delivering up to five injections per cycle, permitting much more precise control than was possible with the previous 1,350 bar system. The U2 generates a total power output of 94 kW (126 hp) at 4,000rpm, with 260 Nm (192 lb-ft) torque at 1900~2750 rpm. More than 90% of the maximum torque is available at 1,500 rpm.
Other refinements include a variable swirl control system which helps to minimize emissions and a chain drive for improved reliability in valve train control and a bed plate-type lower crankcase for better block rigidity, lower noise, vibration and harshness. The auxiliary belt is a serpentine-type for improved reliability and compact packaging.
The U2 claims to be the quietest engine in its class, measuring up to two dBA lower than leading competitors. During the course of development, the main sources of noise emission were identified and appropriate measures were implemented. Since the 1.6 liter engine was equipped with chain drive for valve timing control, the chain and cover systems were identified as one of the main sources of noise. Structural analysis was performed for design improvement and based on modal analysis the chain and head cover structure was reinforced by applying ribs. The shape and structure of the oil pan was also improved as the oil pan was another major source of noise emissions. Structural analysis was also done to investigate the effects of rib shape and rib location on noise characteristics and thus, developers were able to arrive at an optimally shaped oil pan.
The U engine, first introduced in 2005, has grown to a family of engines that includes 1.1-liter 3-cylinder and 1.5-liter 4-cylinder variants which utilize a common architecture and share components for maximum manufacturing efficiency.