SUVs have become a mainstay for numerous car owners who swear by them for the utility, capability and reliability they offer. SUVs have been around for a long time, with origins which can be traced back to the 1930s when militaries across the globe were developing vehicles which had the capability of tackling or being deployed in any terrain. One of the most crucial elements in an SUV or any utility vehicle is the drivetrain system. SUVs use 2 types of powertrain systems – 4X4 & AWD. This time on Understanding Your Car we shall explain you the differences between 4X4 & AWD, read on to know more.
SUVs are designed to be rugged, tough vehicles which have the capability to tackle even the harshest terrain conditions. Come rock, sand, mud or snow SUVs can take on anything and take you anywhere. A car requires traction to maintain good grip and movement while being driven on a surface/terrain. The terrain conditions on an off-road surface (Rock, sand, mud, snow etc.) are different from ones on a tarmac road. Off-road surfaces often vary in the traction levels offered to the car; hence the car loses grip and cannot be driven effectively. This is where the 4X4/AWD system comes into play and provides optimal grip to the car by transferring engine power to the required wheels. A 4X4 or AWD system is essentially a power distribution system. A large number of cars around the world use a 2WD (Two Wheel Drive) powertrain system. This system distributes the power generated either to the front 2 wheels or the rear 2 wheels; motion is generated and the car moves forward. A 4X4, AWD system distributes the power equally to all 4 wheels of the car, hence there is an equal distribution of torque to all wheels and good levels of grip are maintained even on off-road conditions. Both 4X4 and AWD are similar with respect to power delivery for the wheels but the key difference lies in the way they operate. An All-Wheel Drive system uses the power generated by the engine and equally powers all wheels of the car (both front and rear). AWD systems come in configurations; full-time or part-time which vary from car manufacturer to car manufacturer. In the full-time mode the AWD is engaged always and power is sent to all 4 wheels throughout. The benefit of full-time AWD is the fact that better handling, power is available for use on the use. This also helps in slippery conditions as the car gets more traction to move forward. In the part time AWD mode the power is sent to the driven wheels (either front or rear, varies from car to car). The system then automatically engages the other two wheels as and when road, terrain conditions demand. With the help of an electronic computer, sensors the system monitors and controls the power sent to the wheels.
The 4X4 system is a more traditional system. The first SUVs and tough terrain tackling vehicles all used a 4X4 system. The 4X4 system is designed to work better in a more challenging off-road environment. This system is designed to send power to all 4 wheels of the vehicle equally and increase traction where required. 4X4 systems tend to be more robust and durable then their AWD counterparts and can handle more rugged terrain too. 4X4 or 4WD uses a series of transfer cases and couplings to provide maximum torque to the wheels where required under a variety of terrain and surface conditions. 4X4 systems come with a low, high range of gear ratios which can be engaged by the driver when need be. The low range provides maximum traction in an off-road environment while the high range is useful in slippery conditions such as snow, loose sand, gravel or ice. These two gear ratios can be engaged via an electronic switch or a mechanical gear lever. Like AWD the 4X4 system comes in 2 configurations a full-time and a part-time mode. Full time mode offers power to all wheels equally on a continuous basis. The part-time 4X4 system is a more old-school system which can be found in large SUVs, trucks to take on the harshest of driving conditions. In this system the vehicle is generally driven by the rear wheels, and the decision to engage the 4X4 is at the discretion of the driver as and when required. Some systems also allow the driver to lock the differentials at for extra traction in extreme conditions. 4X4 systems are always preferred while extreme off-roading as they offer a higher level of grip and power the driver. While SUVs generally come equipped with 4X4 or AWD systems, however other car types (sedan, hatchback etc.) also some equipped with such systems. The availability, compatibility varies from one car manufacturer to another. The 4X4/AWD system is not going away anytime soon and is here to say as the demands of tough all terrain tackling vehicles will always be present. With the aid of latest cutting edge technology these systems will only improve for the better.