Honest Auto Tech

Hello This is Bhushan. I will try to give you AutoGyan (Automotive information)/Honest Automobile Reviews.

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Sunday, September 16, 2018

What is difference between 4WD /4 X 4, and AWD ?


Hello Everyone, 
Welcome to my new Blog,

The popularity for SUVs is considerably large in Indian Market, people love SUV's bold styling, now manufacturers are providing crossovers looks in hatchbacks also. It is another part of the market and peoples like.

But if SUVs are equipped with 4WD/4 X 4 or AWD what does it means?
In India, Many trucks, SUVs, and cars come with all-wheel-drive or four-wheel-drive. The other drive configurations you will see a car have is either front-wheel-drive which is popular in economy focused cars or rear-wheel-drive which is common for many big cars like SUVs but India exception will be always there, keep it side.

In India, Mahindra XUV 5OO comes with AWD
But Thar Comes with 4WD or say 4 X 4.

But why do manufacturer use different terms? Isn't All Wheel Drive (AWD) and 4 Wheel Drive (4WD) are the same?  I'll explain each in detail.


4 Wheel Drive (4 X 4), (4WD)


For an instance assume both as same, You would think since cars have four wheels that all-wheel drive would mean the same thing as four-wheel drive, but it doesn’t. The main problem with all-wheel drive revolves around the differential in the transfer case. In high grip situations such as driving on the road, wheel slip isn’t likely to happen, meaning that all four wheels can put power to the ground. In an off-road situation, wheel slip is constantly occurring. Low grip situations uncover one major flaw of a basic all-wheel-drive system: all power going to one axle.
An open differential inside an axle will send all the power to the wheel with the least amount of grip which is an inherent flaw of the open differential. Unfortunately, the same problems happen in open center differentials. The axle with the least traction will get the most drive force which can become an issue when climbing up a steep hill because the front axle will begin to slip and inevitably receive all the drive power. This problem only gets worse if the vehicle uses open differentials in the axles, as one wheel can receive all the power which defeats the purpose of all-wheel-drive.
Four-wheel drive combats this issue by removing the center differential and locking power at a 50/50 split between the drive axles, meaning one axle will never receive more drive power than another which is very important for off-road situations. This design also introduces the ability to have multiple ratios in the transfer case. One ratio can be much lower which multiplies torque, but limits drive speed which is perfect for “crawling” situations. 

What Kind of 4WD Do I Have?
It’s important to know exactly how your 4WD system works. For older vehicles, you may have come to a complete stop first and put your vehicle in neutral or park before engaging 4WD.
Newer vehicles, however, can normally activate 4WD with a simple push of a button. Some modern 4WD systems turn on automatically whenever it detects one or more of the wheels slipping.
Each system—part-time, full-time, manual shift, and fully automatic—all have different requirements for engagement and disengagement. It’s important to check your owner’s manual.

When to Use 4WD?

Use 4WD in the following situations:
  • When you need additional torque/power, such as pulling heavy loads at slow speeds.
  • When you descending at slow speeds while hauling a heavy load.
  • When you are going over steep inclines and declines, such as rocky situations.
  • When you are stuck in snow, mud, or sand; however, stop immediately if your wheels are spinning and follow the advice in this article.

Four-Wheel Drive Advantages

The main benefits of 4WD are traction and power. Have you ever seen those Thars and Jeeps are climbing over rocks? That’s 4WD in action.
If you are climbing a steep hill or are off-roading, you will want increased power in order to get over obstacles and climb steep hills. While 2WD will get you over even on the Smmoth Indian Highways but if you are off-roading you will probably want the extra power that comes with 4WD.
  • 4WD improves traction in dangerous driving conditions, such as snow, ice, rocks, and other scenarios that can make control difficult. By engaging both sets of wheels, traction and control improve.
  • Additional weight contributes to a better grip on the road.
  • 4WD is great for those who like off-roading.
If you frequently drive in conditions where there is low traction, or if you enjoy off-roading, you will greatly benefit from the four-wheel drive.

Four-Wheel Drive Disadvantages

In most cases, 4WD is not necessary. It uses more fuel and can also lead to more situations where you can get stuck. Save money and fuel by only using 4WD when you need it.
  • The main disadvantage of 4WD is an added cost for purchase, maintenance, and fuel. The extra equipment (differentials, transfer case, etc.) adds complexity and weight to the vehicle, increasing initial market value, tire wear, and the cost of repairs and maintenance.
  • The added power and weight of 4WD and AWD systems require more fuel, making them less efficient than their 2WD counterparts.
  • Added weight improves traction and control, but it also increases the braking distance required to make a complete stop. Lighter vehicles can avoid collision easier than heavier vehicles.
  • 4WD and AWD can cause overconfidence in drivers, ironically leading to more situations where you can become stuck.
  • Although 4WD improves traction, slow down and use extreme caution on icy, snowy, and slick roads. Overconfidence can lead to dangerous accidents.

4WD Tips 

  • 4WD vehicles work best when they are regularly used and maintained according to manufacturer recommendations. If you don’t use the 4WD system for extended periods of time, the seals can dry out. It’s best to keep the system lubricated by activating it at least once every few months.
  • Only use 4WD when you need it to save as much gas and money as possible. Driving 4WD on mild, dry conditions can do damage to your front axles, differential gears, and other parts. Always use 2WD on dry pavement.
  • If you get stuck, switch to 4WD and slowly depress the gas pedal to get yourself out. If the wheels start spinning, stop before you dig yourself a deeper hole.


All Wheel Drive


All-wheel drives system is in a car like the Mahindra XUV5OO and Renault Duster. Sometimes this system is used in larger trucks and SUVs. Like the name implies, the all-wheel-drive system powers all four wheels. If you drive on a straight highway you may never even need the additional grip of all-wheel-drive, but climates, where you are likely to experience rain or snow, is where all-wheel-drive is great to have.
Unfortunately, splitting the power 50/50 between the two axles won’t work in high grip situations such as on the street. When taking a turn the wheels on the front axle will move at a slower than the wheels on the rear axle, the axles will rotate at different speeds while cornering. If the power is locked 50/50, then the axles cannot move at different speeds. The lack of different speeds during a corner causes binding in the drivetrain, which will put the transfer-case, axles, differentials, and driveshafts under extreme load causing some damage over time.
The idea of all-wheel-drive is to drive both axles, but allow a difference in speed between the front and rear axles. This concept works by just adding a differential in the transfer-case which works exactly like a differential in an axle. If you didn’t already know, the purpose of a differential is to allow for differences in wheel speed, or in this case, differences in axle speed. During a turn more drive speed can be sent to the front or rear axle which eliminates the binding issue we mentioned.
Many AWD systems utilize this feature to increase fuel economy. Front wheel drive cars inherently use less energy to accelerate. By sending all the power to the front axle, unless wheel slip is detected, you can increase fuel economy while also maintaining high levels of grip when needed. Not all all-wheel-drive systems are front-wheel biased, but all-wheel-drive cars are because the engine is already mounted transversely. By comparison, many all-wheel-drive trucks and SUVs have the engine mounted longitudinally, so they have more a rear-wheel bias if anything. This all comes down to how the manufacturer designs the system, and it’s different in almost every car.

Many drivers would never choose a vehicle without all-wheel drive. But with today's traction controls and electronic systems, is AWD really necessary? We examined the benefits and disadvantages of AWD for shoppers who may choose the system, without thinking twice.

Advantages 
  1. Extra Traction: There's no question that AWD improves traction. The reason is it allows all four wheels to spin, which can be helpful if two of them are on a slick or slippery surface. It can also be helpful if two wheels are stuck. That's a reality that many drivers in hilly areas have to face. For that reason, I strongly recommend AWD if you live where you often live in Hilly Areas.

Disadvantages 
  1. Modern Technology?: Can modern technology help a 2-wheel-drive car replace an AWD one? Not quite -- but it's getting there. Many modern cars offer traction control and stability control, which help keep you on the road even in difficult conditions. Most can completely cut power to one wheel, if necessary, or control a vehicle's skid to eliminate the possibility of it going out of control.
  2. Low Resale Value: India is a very cost Sensitive market, people here don't need an AWD vehicle as it is high on fuel consumption, high maintenance, and high cost.


Conclusion 


In India, if you are Enthusiastic Driver loves offroading then go for the 4WD drive only which is the best available option in the market, like 

  • Mahindra Thar
  • Mahindra Scorpio 
  • Maruti Gypsy
  • Force Gurkha
  • Tata Safari Storme
  • Tata Hexa
  • Ford Endeavour

it doesn't make any sense buying AWD in India, because here the climate is ok no snowfalls, no continuous rains, but yes if you want more traction and often drive in hilly or muddy areas, and do some simple offroading AWD makes sense.

  • Mahindra XUV5OO
  • Renault Duster
  • Honda CRV

Guys if you feel reading it worth, please share among your circles, do comment and keeping following ..!!




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