E-Four (short for Electrical 4WD System),[1] eFour, AWD-i, or AWD-e was developed by Toyota. Front wheels are powered directly by the hybrid powertrain, rear wheels are powered by a dedicated electric motor with its own power control unit, reduction gear and differential. Amount of torque transferred to the rear wheels is automatically adjusted by the vehicle's electronic control unit according to driving conditions. E-Four also adds additional regenerative braking.[2] In North America, Toyota uses the term AWD-i (All-Wheel Drive with Intelligence).[3][4][5] There is no drive shaft between the front combustion engine and rear wheels. The rear wheels only receive power and torque from the rear electric motor(s).[6][7][8]

E-Four was first implemented in the 2001 Toyota Estima Hybrid and is used in several Toyota and Lexus cars, e.g. 2016 Toyota RAV4,[9] Lexus NX 300h, Lexus RX 450h,[10] and Toyota Prius AWD-e,[11] and in the future may be used in the standard fifth generation Toyota Prius.[12] In Japan, the all-wheel-drive Prius has been available since 2015 and bumps the price by about $1700. The compact HV4WD E-Four used for the Prius adds little weight and does not reduce the fuel economy or interior storage. A few weeks before the November 2018 Los Angeles Auto Show, Toyota issued a press release with text and images featuring the car in snowy conditions, suggesting the E-Four package would likely debut in the 2019 U.S. model at the show.[13]

References

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  1. ^ "Electrical 4WD System (E-Four)[HV]". Toyota Motor Corporation Global Website. Retrieved 2018-11-09.[dead link]
  2. ^ Halvorson, Bengt (2018-11-09). "Toyota teases all-wheel-drive Prius for LA auto show debut". Green Car Reports. Retrieved 2018-11-09.
  3. ^ Schreffler, Roger (2018-06-04). "Mitsubishi Enhances All-Wheel-Drive Technology". WardsAuto. Retrieved 2018-11-09.
  4. ^ "Gen 5 2019 Toyota RAV4 debuts at New York International Auto Show; 2.5L inline-4 and Toyota Hybrid System". Green Car Congress. 2018-03-28. Retrieved 2018-11-09.
  5. ^ "AWD-i All-Wheel Drive". Toyota Canada Inc. 2016-06-27. Retrieved 2018-11-09 – via YouTube.
  6. ^ "Toyota all-wheel drive. E-Four" (in English, Russian, and Japanese). 2021-03-30. Archived from the original on 2021-03-30. Retrieved 2021-03-30.[dead link]
  7. ^ "What You Need to Know About Toyota's Hybrid All-Wheel Drive". Kelley Blue Book. 2020-08-12. Retrieved 2021-04-30.
  8. ^ Goreham, John (2020-08-27). "2021 Toyota RAV4 Prime's Mysterious All-Wheel Drive System Explained". Torque News. Retrieved 2022-07-30.
  9. ^ "New Lexus NX 300h gets a grip with E-Four all-wheel drive". 2014-09-16. Archived from the original on 2015-11-27. Retrieved 2015-12-03.
  10. ^ Kevin (2015-09-08). "2016 Lexus RX 350 & RX 450h Preview". lexusenthusiast.com. Retrieved 2024-05-16.
  11. ^ Sabatini, Jeff (2019-06-14). "2019 Toyota Prius AWD-e — AWD Hybrid Fuel Miser". caranddriver.com. Retrieved 2024-05-16.
  12. ^ "Toyota details powertrain advances in Gen4 Prius; available E-Four system for all-wheel drive (Not for US)". greencarcongress.com. 2015-10-13. Retrieved 2024-05-16.
  13. ^ Golson, Daniel (2018-11-08). "The 2019 Toyota Prius Is Likely Getting All-Wheel Drive". Car and Driver. Retrieved 2018-11-09.
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