Hyundai Nu engine
The Hyundai Nu engine was introduced in the 2011 Hyundai Elantra to replace the previous Beta engines. It was designed to fill the gap between the new Gamma 1.6L and the 2.0L Theta II. Nu MPi

1.8L (G4NB) 
The  Nu features a bore x stroke of  with a compression ratio of 10.3:1 or 10.5:1 depending on the revision. This engine features MPI, and Dual-Continuous Variable Valve Timing aka D-CVVT. Power output is  at 6,500 rpm with  of torque at 4,700 rpm. Hyundai Nu engine Specification:

 Displacement: 
 Bore x stroke of  (offset crank to cylinder bore)
 Compression ratio 10.3:1–10.5:1
 Power:  @ 6,500 rpm
 Torque:  @ 4,700 rpm
 Redline 6,800 rpm
 Combustion Fuel system: MPI
 Valvetrain: Chain driven roller DOHC 16V D-CVVT 
 Cylinder block & head: Aluminum 
 Intake: Valve controlled Variable Induction System

Applications

Hyundai Elantra (MD) (2010–2015)
Hyundai i30 (GD) (2011–2017)
Hyundai Mistra (2014–present)
Kia Forte (YD) (2013–2016)
Kia K4 (2014–2021)

2.0L (G4NA)
The Nu  version of this engine features the same  bore but with a longer stroke of . First revision of the G4NA engine makes  @ 6,500 rpm and  at 4,800 rpm while later revisions produce  @ 6,200 rpm and  at 4,500 rpm. Applications
Hyundai Creta (GS) (2014–2020)
Hyundai Creta (SU2r) (2021–2022)
Hyundai Elantra (UD) (2013–2015)
Hyundai Elantra (AD) (2015–2020)
Hyundai i40 (2011–2019)
Hyundai Mistra (CF) (2013–2020)
Hyundai Sonata (YF) (2014)
 Hyundai Tucson/ix35 (LM) (2013–2015)
Hyundai Tucson (TL) (2015–2018)
Kia Carens (RP) (2013–2019)
Kia Forte (YD) (2012–2018)
Kia K4 (2014–2021)
Kia KX3 (KC) (2015–2019)
Kia Soul (2012–2019)
Kia Sportage (2014–2021)

2.0L CVVL (G4ND)
Primary change is adding the CVVL, the engine produces  @ 6,700 rpm and  at 4,800 rpm. Applications
Hyundai Sonata (LF) (2014–2019)
Kia Optima (2012–2019)

2.0L Atkinson Cycle (G4NH)
The Atkinson Cycle version of the Nu MPi 2.0L was first released for the sixth generation Hyundai Elantra, compression ratio is 12.5:1 and it produces  @ 6,200 rpm with  of torque at 4,500 rpm. The engine promises improved fuel economy vs the Nu MPi 2.0L (G4NA) engine and better thermal efficiency. Applications
Hyundai Elantra (AD) (2015–2020)
Hyundai Kona (OS) (2017–2020)
Hyundai Tucson (TL) (2015–2020)
Hyundai Veloster (JS) (2018–2020)
Kia Forte (BD) (2018–present)
Kia Seltos (2019–present)
Kia Soul (SK3) (2019–present)

Nu GDi

2.0L (G4NC) 
The Nu GDi  version of this engine features the same  bore but with a longer stroke of  that produces  at 6,500 rpm with  of torque at 4,700 rpm. Applications
Hyundai Elantra (MD) (2013–2015)
Hyundai Elantra Coupe (JK) (2014)
Hyundai i30 (GD) (2014–2016)
Hyundai i30 (PD) (2016–present)
Hyundai i40 (2012–2019)
Hyundai Tucson (LM) (2013–2015)
Hyundai Tucson (TL) (2015–2020)
Kia Carens (RP) (2013–2019)
Kia Forte (YD) (2012–2018)
Kia KX5 (2015–2021)
Kia KX7 (2016–2022)
Kia Soul (2012–2019)
Kia Sportage (QL) (2015–2021)
Kia Sportage Ace (NP) (2021–present)

Nu Flex
Flex fuel compatible engine of the Nu MPi. 2.0L (F4NA)

The Nu FLEX  engine makes  at 6,200 rpm with  of torque at 4,700 rpm. Applications
Hyundai Creta (GS) (2017–2021)
Kia Sportage (QL) (2015–2021)

Nu Hybrid

2.0L MPi Hybrid (G4NE)
The Nu MPi Hybrid version of this engine combines a 2.0L engine with an electric motor and a battery, the petrol engine makes  at 6,000 rpm with  of torque at 5,000 rpm. Applications
Hyundai Sonata Hybrid (2011–2014)
Kia Optima Hybrid (2011–2015)

2.0L GDi Hybrid (G4NG)
The Nu GDi Hybrid version of this engine combines a 2.0L engine with an electric motor and a 1.76KWh battery, the petrol engine makes  at 6,000 rpm with  of torque at 5,000 rpm while the electric motor makes  with  of torque for a combined power rating of . Applications
Hyundai Sonata Hybrid (2014–2019)
Kia Optima Hybrid (2015–2019)

Nu LPi
Uses Liquefied petroleum gas instead. 2.0L (L4NA)

The Nu LPi  version of the engine makes  at 6,200 rpm with  of torque at 4,200 rpm. Applications
Hyundai Sonata (2012–2023)
Kia Carens (RP) (2013–2018)
Kia Optima (2011–2021)

Engine recall
On December 2, 2020, Hyundai and Kia recalled 423,000 vehicles equipped with various engines following a joint review by Hyundai and the NHTSA, of which the Nu GDi engines were a part of. Affected vehicles include the 2016 Hyundai Sonata Hybrid, 2014-2015 Kia Forte and Forte Koup, and the 2014-2015 Kia Soul. See also
List of Hyundai engines

References

Nu
Nu Engine in the LF Hyundai Sonata Hybrid
http://www.hyundainews.com/us/en/models/sonata-hybrid/2017
Straight-four engines
Gasoline engines by model