AWD VS 4x4 | How it Works | Donut Media

Donut
19 Sept 201810:22
EducationalLearning
32 Likes 10 Comments

TLDRThis engaging video script delves into the intricacies of all-wheel drive (AWD) and four-wheel drive (4WD) systems, highlighting their differences and applications. It explains that while both systems enhance traction, they operate differently. AWD typically powers all wheels constantly, making it ideal for various surfaces but less fuel-efficient. 4WD, on the other hand, allows drivers to switch between two and four-wheel power, offering versatility for different terrains. The script also touches on part-time 4WD, full-time 4WD, and individual wheel drive (IWD), showcasing how technology like Torsen differentials and electronic controls distribute power effectively. The humorous analogy of Phil Collins and Peter Gabriel's drumming speeds illustrates the concept of wheel speed variance and the role of differentials in preventing binding. The video concludes with a sponsorship message, emphasizing the convenience and flexibility of a clothing subscription service.

Takeaways
  • 🚗 Four-wheel drive (4WD) and all-wheel drive (AWD) are not the same; they serve different purposes and have distinct mechanisms.
  • 🔄 Four-wheel drive is divided into part-time and full-time, with part-time being more common on modern vehicles and offering a switch between 2WD and 4WD.
  • 🔩 Full-time 4WD is typically found on large trucks and SUVs, providing constant power to all wheels and is more reliable off-road.
  • 🔧 Part-time 4WD uses a transfer case to switch between 2WD and 4WD modes, with high and low lock options for different driving conditions.
  • 🛠️ Differentials are crucial in drivetrains, allowing wheels to spin at different speeds and preventing issues like binding when turning.
  • 🚙 AWD systems provide advantages over 2WD, especially in traction, as seen in vehicles that power all four wheels, which is beneficial in slippery conditions.
  • 🚘 AWD can cause binding on high traction surfaces if not designed properly, as all wheels spinning at the same speed can create tension and stress on the drivetrain.
  • 🚧 Full-time AWD is less desirable for extreme off-roading but is the safest on all surfaces, often found in vehicles like Audi and Subaru.
  • 🔋 Some AWD vehicles use two motors, one for each axle, or even individual wheel drive (IWD) with electric motors for each wheel, offering precise control.
  • 🌟 The term 'AWD' has been used interchangeably with '4WD' historically, but modern AWD generally means permanent multiple wheel drive.
  • ⛽️ A downside of AWD systems is increased fuel consumption due to the additional power required to drive all four wheels.
Q & A

  • What is the basic difference between all-wheel drive and four-wheel drive?

    -All-wheel drive (AWD) provides power to all four wheels at all times, while four-wheel drive (4WD) can be either part-time or full-time. Part-time 4WD can switch between two-wheel and four-wheel drive, and full-time 4WD keeps all four wheels powered at all times.

  • What does the term '4x4' signify in vehicles?

    -The term '4x4' signifies that the vehicle has four wheels, and all four wheels are being driven or powered.

  • Why do all-wheel drive systems have advantages over two-wheel drive systems?

    -All-wheel drive systems have advantages over two-wheel drive systems primarily in traction. Vehicles with power distributed to all four wheels inherently have more traction than those that use only two powered wheels, making them more suitable for various road conditions.

  • What is the issue with evenly distributing power to all four wheels on high traction surfaces?

    -On high traction surfaces, evenly distributing power to all four wheels can cause a phenomenon known as 'binding' or 'wind up.' This happens when the wheels spin at the same speed and cannot adjust to different speeds required during turns, which can be harmful to the vehicle.

  • How do differentials solve the problem of binding in all-wheel drive systems?

    -Differentials are mechanisms that allow the wheels to spin at different speeds. They can be mechanical or hydraulic and help prevent stress on the drive shaft that occurs when one wheel spins slower than the other, thus eliminating binding.

  • What is the main difference between full-time and part-time four-wheel drive systems?

    -Full-time four-wheel drive systems power all wheels continuously, often found in large trucks and SUVs, while part-time four-wheel drive systems allow drivers to switch between two-wheel and four-wheel drive modes, making them more versatile for different driving conditions.

  • What is the role of a transfer case in a part-time four-wheel drive system?

    -In a part-time four-wheel drive system, the transfer case is responsible for switching between the drive systems. It has gears that determine whether power is sent to the front wheels, the rear wheels, or both.

  • How does a Torsen differential work in an all-wheel drive system?

    -A Torsen differential, commonly found in all-wheel drive systems like those in Audi or Subaru vehicles, uses oil pressure to sense torque loss in one of the output shafts. If it detects a loss, it will send more power to the other wheels to maintain effective traction.

  • What is the term for an all-wheel drive system that uses two motors, one for each axle?

    -The term for an all-wheel drive system that uses two motors, one for each axle, is dual-motor all-wheel drive. An example of this is the Tesla Model S.

  • What is Individual Wheel Drive (IWD), and how does it differ from traditional all-wheel drive systems?

    -Individual Wheel Drive (IWD) is a system where each wheel has its own motor, allowing the car's computer to adjust individual torque levels in milliseconds. This system is primarily associated with electric motors and offers more precise control over each wheel's power compared to traditional AWD systems.

  • Why are all-wheel drive vehicles less desirable for extreme off-roading despite being safe on all surfaces?

    -All-wheel drive vehicles are less desirable for extreme off-roading because the system is designed for constant power distribution to all wheels, which is not as effective for navigating challenging off-road terrain that may require differential speed or torque application to specific wheels.

  • What is the promotional offer from Bombfell mentioned in the script, and how can viewers take advantage of it?

    -The promotional offer from Bombfell is $25 off the first purchase for new customers. Viewers can take advantage of this offer by visiting bombfell.com and using the promo code provided in the script (likely 'sciencegarage' based on the context).

Outlines
00:00
🚗 Understanding All-Wheel and Four-Wheel Drive Systems

This paragraph delves into the differences between all-wheel drive (AWD) and four-wheel drive (4WD) systems. It begins by likening the confusion between these systems to that of famous musicians Phil Collins and Peter Gabriel, emphasizing that while they seem similar, they are distinct. The explanation covers the basics of 4WD, including part-time and full-time configurations, and how they provide more traction than 2WD systems. The importance of differentials in allowing wheels to spin at different speeds is highlighted, as is the challenge of 'binding' that can occur on high traction surfaces. The paragraph also touches on the historical development of AWD systems and the marketing terms used to describe them, such as 'four by four,' which are often more about marketing than technical accuracy.

05:01
🔄 The Mechanics of Part-Time and Full-Time Four-Wheel Drive

The second paragraph provides an in-depth look at part-time and full-time four-wheel drive systems. It explains that full-time 4WD is typically found in large trucks and SUVs, where all wheels are powered at all times, and this system is highly reliable for off-roading. The paragraph also discusses part-time 4WD, which allows drivers to choose between two-wheel and four-wheel drive modes, making it versatile for different driving conditions. The use of a transfer case to switch between drive modes is described, along with the different gear ratios for high and low-lock settings suitable for various off-road situations. The paragraph further explores the concept of permanent AWD, where all wheels are powered continuously, making it safe for all surfaces but less efficient for extreme off-roading. It also mentions alternative drivetrains like Individual Wheel Drive (IWD), used in electric vehicles, which can adjust torque levels for each wheel independently.

10:03
🛍️ Sponsorship and Engagement with the Audience

The final paragraph shifts away from the technical discussion of drivetrains to address the audience directly. It includes a sponsorship message for Bombfell, a service that provides an easy way for men to get better clothes. The speaker shares a personal anecdote about their experience with the service, highlighting the convenience and flexibility of the clothing selection process. The paragraph also encourages the audience to subscribe to the channel, follow on social media, and check out new content, such as the episode of 'Up to Speed.' It ends with a humorous note about a personal vehicle's mileage, adding a touch of personality to the engagement with the audience.

Mindmap
Keywords
💡All-Wheel Drive (AWD)
All-Wheel Drive (AWD) is a drivetrain configuration where all four wheels of a vehicle receive power from the engine. It enhances traction and stability, especially in challenging conditions. In the video, AWD is contrasted with four-wheel drive, highlighting its advantages in terms of traction over two-wheel drive systems and its application in various vehicle platforms.
💡Four-Wheel Drive (4WD)
Four-Wheel Drive (4WD) is a system where torque is supplied to four wheels simultaneously. The script differentiates between part-time and full-time 4WD, explaining that part-time 4WD allows the driver to switch between two-wheel and four-wheel drive, while full-time 4WD maintains power to all wheels continuously. It is particularly useful for off-roading but less efficient on high traction surfaces due to the risk of 'binding'.
💡Part-Time Four-Wheel Drive
Part-Time Four-Wheel Drive is a system that provides the driver with the option to switch between two-wheel drive for normal conditions and four-wheel drive for low-traction situations. The video mentions that this system is common on modern cars and is suitable for quick transitions from paved roads to off-road terrain. It uses a transfer case to switch between drive modes.
💡Full-Time Four-Wheel Drive
Full-Time Four-Wheel Drive refers to a drivetrain where all wheels are powered at all times without the need for a driver to switch modes. It is typically found in large trucks and SUVs and is characterized by its reliability in off-road conditions. The video points out that while it's beneficial for off-roading, it can cause issues like binding on high traction surfaces.
💡Differential
A Differential is a mechanical component that allows wheels to rotate at different speeds, which is necessary when turning. It can be mechanical or hydraulic and is crucial in preventing stress on the driveshaft. In the context of the video, differentials are highlighted as a solution to the problem of 'binding' in AWD and 4WD systems, especially on high traction surfaces.
💡Traction
Traction refers to the grip of a vehicle's wheels on the surface it is driving on. The video emphasizes that vehicles with AWD or 4WD have better traction than those with two-wheel drive, which is particularly beneficial in slippery or muddy conditions. Traction is a central theme as it underpins the advantages of the drivetrains discussed.
💡Binding
Binding occurs when there is a tension buildup in a vehicle's drivetrain because the wheels are spinning at different speeds, particularly during turns. The video explains that binding can be detrimental to a vehicle, especially on high traction surfaces, and it is prevented by the use of differentials in AWD and 4WD systems.
💡Transfer Case
A Transfer Case is a gearbox that allows the driver to switch between different drive modes, such as two-wheel drive and four-wheel drive. It is a key component in part-time four-wheel drive systems, enabling the vehicle to adapt to different driving conditions. The video uses the transfer case as an example of how power is distributed in a 4WD system.
💡Torsen Differential
A Torsen Differential is a type of differential that automatically distributes torque between the front and rear wheels based on available traction. It is used in some AWD systems to improve handling and performance. The video mentions Torsen differentials in the context of full-time AWD vehicles like Audi and Subaru, noting their ability to send power where it's most effective.
💡Individual Wheel Drive (IWD)
Individual Wheel Drive (IWD) is a drivetrain technology where each wheel is powered independently, often associated with electric vehicles. The video points out that in IWD systems, such as those found in the Tesla Model S or Mars rovers, each wheel has its own motor, allowing for precise control of torque at each wheel, which can provide exceptional maneuverability and performance.
💡Off-Roading
Off-Roading is the act of driving a vehicle on rough or unpaved terrain. The video discusses how AWD and 4WD systems are particularly beneficial for off-roading due to their enhanced traction and ability to handle challenging conditions like steep, slippery hills. It is a key context for the discussion of the advantages of different drivetrains.
Highlights

Four-wheel drive (4WD) and all-wheel drive (AWD) are often confused but they serve different purposes and have distinct mechanisms.

4WD is divided into part-time and full-time, with part-time being more common on modern cars, allowing a switch between two-wheel and four-wheel drive.

Full-time 4WD, often found in large trucks and SUVs, has all wheels spinning at all times and is the most reliable for off-road driving.

Part-time 4WD systems use a transfer case to switch between drive systems, distributing torque between the front and rear axles.

AWD systems provide advantages over 2WD systems primarily in traction, as power to all four wheels inherently offers more grip.

Rear-wheel drive cars can struggle in low traction situations, as power is transferred to the wheel with the least resistance.

Front-wheel drive cars have better traction than rear-wheel drive due to the engine's weight over the driven wheels.

Binding can occur when all four wheels spin at the same speed, especially during turns, causing tension and potential damage to the vehicle.

Differentials are crucial in preventing binding by allowing wheels to spin at different speeds.

Permanent AWD systems, like those found in some Audi and Subaru models, use a Torsen differential to distribute power effectively.

Electronic control in some AWD vehicles allows for variable power distribution, enhancing performance in different driving modes.

IWD or individual wheel drive, where each wheel has its own motor, is associated with electric vehicles and offers precise torque control.

Permanent AWD systems are safer on all surfaces but are less fuel-efficient due to the constant power to all wheels.

All-wheel drive designations like '4x4' are often used for marketing rather than accurately describing the vehicle's functionality.

The Tesla Model S uses two motors, one for each axle, as an example of an AWD system in electric vehicles.

The Mars rover uses an IWD system, with each of its six wheels controlled by individual motors for enhanced maneuverability.

The video also discusses the practical applications and benefits of different drivetrains in various driving conditions.

Sponsor content features Bombfell, a service that offers personalized clothing selections for men with a flexible subscription model.

Transcripts

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Drivetrain4x4AWDOff-RoadingVehicle DynamicsDifferentialsTractionAutomotiveSUVsTrucksTechnology