Hyundai's New U2 1.6 CRDi Diesel Engine Achieves
Best-in-Class Performance for Compact Cars

- Cleaner, quieter, more fuel efficient
- Fuel economy rating of 4.5L/100km (48 mpg)
- Low CO2 emissions: 119g CO2 /km and better
- Emissions Euro 4 & Euro 5 compliant
- Best power & torque in class
: 128 PS (126 bhp) - 260Nm (26.5kgm)@1900~2750rpm

Introduction
The Powertrain R&D Center of Hyundai Motor Co. has completed development of a cleaner, quieter and more fuel efficient diesel engine for compact passenger vehicles (C-segment and below).
Displacing 1,582cc, the U2 engine is characterized by its class leading performance and fuel consumption realized by refined combustion system and calibration
"Hyundai’s diesel engine development capabilities are second to none in the world and the proof can be seen in our new U2 engine. It is a class leader in almost every aspect and we are really proud of this," said Dr. Lee Hyun-Soon, vice chairman and chief technology officer of the Hyundai-Kia Corporate R&D Division.
By combining advanced engineering know-how with state-of-the-art technologies such as a variable geometry turbocharger (VGT), a variable swirl control system, a close-coupled diesel particulate filter (DPF) and an electronically controlled exhaust gas recirculation (EGR) cooling system, the U2 engine development team was able to reach highly competitive status. This endows the U2 engine with outstanding fuel economy of 4.5 L/100 km corresponding to 119 g/km CO2 emission and low emission potential making it fully compliant with Euro 4 emission standard and the even stricter Euro 5 standard.

Combustion System and Performance

At the heart of the combustion system is the second generation common rail fuel injection system which is capable of activating up to five injections per cycle with much more flexibility and precision than the preceding 1350 bar system. Combined with VGT and optimized combustion system, U2 1.6 liter engine delivers an impressive maximum power of 128 PS (94 kW) at 4000 rpm and maximum torque of 26.5 kgm (260 Nm) through wide engine speed ranging from 1900 to 2750 rpm, both of which are marking the class leading level.
Other point to be emphasized is the balance between power output and lower end torque, which is essential for vehicle drivability. In parallel with the class leading power output, brake mean effective pressure (BMEP) at 1000 rpm reaches 11 bars and more than 90 % of maximum torque is available at 1500 rpm. And this balanced performance leads to excellent drivability and acceleration performance.

Installed in Hyundai's new i30 compact hatchback sedan, new U2 1.6 engine achieves a zero to 100km/h acceleration time of 11.0 seconds, striking an ideal balance between spirited performance and maximum fuel economy.

Other refinements include a variable swirl control system which helps to minimize emissions and a chain driven timing system for improved reliability 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.

Aftertreatment System

Although the U2 1.6 liter engine has demonstrated enough potential against Euro 4 emission standard only with diesel oxidation catalyst (DOC), DPF is also available and thereby PM emission was reduced to lower level than 5 mg/km that is the limit for Euro 5.
The substrate of DPF is composed of Aluminum-Titanate and asymmetric cell design is introduced to enhance the ash loading capacity.

Battery Management System

A substantial portion of the reduction in fuel consumption and CO2 emissions was achieved with the new Battery Management System (BMS).
Fuel consumption will be further reduced in upcoming engine variants with the addition of the Intelligent Idle Stop Go (ISG) System. Effectively functioning as a micro hybrid system, BMS manages the ECU, battery sensor and alternator to reduce or increase work loads placed on the alternator in accordance with the battery state of charge, vehicle acceleration or deceleration. As a result, BMS helps improve fuel efficiency by 2 percent.
During acceleration, the ECU sets the alternator output voltage to a low value in order to reduce the alternator workload thus consuming energy stored in the battery. Under deceleration, the ECU sets the alternator output voltage to a high value thereby increasing the alternator workload and thus recharging the battery.
For a further reduction in fuel consumption, the Intelligent Stop and Go system automatically shuts down the engine during periods of prolonged idling according to a pre-defined framework and once the accelerator pedal is depressed, the engine is automatically restarted within a split second. ISG will be applied from July 2009 production and onwards.

NVH Development

The U2 engine claims to be the quietest one in its class, measuring up to two dBA lower than leading competitors.
This target was pursued in one way by optimizing calibration and in the other way by optimizing the engine structure and enhancing the stiffness of powertrain.
Refined calibration was introduced to improve the acoustic behavior and various injection control parameters were optimized by design of experiment (DoE) technology.
Double pilot injection strategy is applied to wide engine operating range covering normal driving mode, which leads to impressive improvement in NVH.

During the course of development, the main sources of noise were pinpointed and appropriate countermeasures were implemented. As U2 1.6 liter engine was equipped with a chain driven timing system, the chain and cylinder head 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 structures were strengthened with reinforcing ribs. The oil pan was proved to be another major source of noise emission. Structural analysis was also done to investigate the effect of shape and location of each rib and to find out the optimal shape of oil pan.

Engine Oil Level Sensor

To better protect the engine, the U2’s oil pan is fitted with an ultrasonic engine oil level sensor which monitors the oil level and temperature while the engine is running. When the oil reaches below a critical level, the sensor triggers “Check Oil” indicator lamp on. For the time being, availability of the U2 oil sensor level is limited to i30 production at Hyundai Motor Manufacturing Czech.

Eco-Type Engine Oil Filter

To save maintenance costs and reduce pollution, the engine oil filter has been redesigned eliminating the need for a spin-on-type metal-case oil filter. The new permanent filter body is made of high pressure die-cast aluminum which contains a filter element and o-ring, both replaceable plus a relief valve and center pipe. With the redesign of the oil filter and the inclusion of the new oil level sensor, the oil change interval has been extended to 30,000 km or every two years, thus reducing ownership costs. This is an improvement from the 20,000km oil change interval recommended on the predecessor U engine.

The U engine, first introduced in 2005, has grown to a family of engines that includes 1.1-liter 3-cylinder, 1.4-liter 4-cylinder and 1.5-liter 4-cylinder variants which utilize a common architecture and share components for maximum manufacturing efficiency.

Six-Speed Manual Transmission

Carbon Multi-Cone Synchronizer Rings
The U2 is mated to a new manual transmission with a sixth gear which boosts fuel economy by an estimated 1.5 percent while the challenge of improvements to shift feeling and precision has been tackled through several measures.
First, multi-cone synchronizer rings were specified. By expanding the friction surface, synchronizing capacity is enlarged and shift effort is reduced. First and second gears feature triple cone synchronizer rings while double cone synchronizer rings are applied to the third through sixth gears. Also, the synchronizer rings (first/second) are made of carbon, a material used in clutch, brake and other demanding high-friction applications. The carbon synchronizer rings offer far superior durability compared to standard brass synchronizer rings.

Modulized Shift Control Assembly
The six-speed's shift control assembly has been totally redesigned into a modular unit resulting in more precise shift quality. As there are a fewer number of parts in the new design, the stack-up chain of parts is greatly reduced resulting in smaller tolerances and higher shift precision. The new module is lighter, simpler and requires less assembly time with reduced margin for error. Within the central control shaft, a new linear-type bearing is used in addition to a conventional rotational bearing to lower friction in the detent pin resulting in lighter and smoother feeling shifts.
Low Noise Gear Profile
The six-speed is also quieter. Using computer aided engineering tools, the profile of the gear teeth has been designed to be insensitive to gear teeth contact transmission error thus minimizing gear noise.
A four-speed automatic with lock-up torque converter is available as an option with the U2.