Differential in Automobile: Types and Working
Changing direction or turning in a corner is quite simple. You just rotate the steering wheel in the desired direction. However, the mechanism behind this process is not as simple as that. While cornering, the vehicle needs a different RPM (Revolution Per Minute) in each rear wheel connected to axle shafts.
A differential in automobiles is a gear mechanism that helps with a driving experience. Let’s know all about differential, including its functionalities, mechanisms and types.
What Is Differential in Automobile?
The differential is a mechanism that uses multiple gears to transmit power and control RPMs in both wheels connected to each side of an axle. While changing a vehicle's direction, it determines and sends the required rotational power and speed onto each axle shaft.
The mechanism involves seamless and inter-connected functioning of different gears, including ring gear, drive shaft bevel gear and differential bevel gear. All these tools stay compact within the differential cover. This sealed box remains connected in between two shafts of the rear-side axle.
Why Is Differential Needed?
Proper functioning of a differential is essential while turning a vehicle. It helps in correct power distribution on left and right wheels. While a car turns on a bend, the differential ensures that the wheel on the inner side of a turning curve gets less torque than the outer one. It enhances the vehicle’s control during cornering.
To understand the importance of this vehicular system, assume that there is no differential in a vehicle. In this scenario, wheels on either side of that car would get a similar RPM every time. As a result, both wheels would travel an equivalent distance, making the car move in a straight line. Thus, it is difficult or almost impossible to approach a corner properly. The vehicle differential in automobiles evades all these inconveniences by controlling cars’ rotational power.
What Are the Types of Differentials in Automobiles?
There are four types of differentials in vehicles, as mentioned below:
1. Open Differential
It is the simplest and most common differential used in vehicles. An open differential helps the wheels get different torque while cornering. It works perfectly under proper road conditions. However, when the car wheels come on a slippery surface, it becomes difficult to tackle a corner. In this situation, the wheel only spins due to lack in traction and does not move in any direction.
2. Limited Slip Differential
The essential functionality of this differential is the same, to share the torque evenly in both wheels. However, it is different from an open differential system in sharing the power when the traction is less or zero on one wheel. It channels more power on the wheel, which has more on-road traction. As a result, even on a slippery road surface, the vehicle keeps moving. You can see its applications on high performance vehicles, race cars, etc.
3. Locking Differentials
Locking differential also creates different RPM on both wheels in a normal corner. However, it enables a vehicle to transfer the entire torque to both wheels if one of them lacks traction. Springs and clutches used in its system lock the differential system (by tightening small gear), and as a result, both wheels get similar power and keep on rotating on their shafts. The vehicle easily moves out even after one wheel gets zero traction as its other wheel functions properly. This differential is ideal for off-road vehicles.
4. Torque Vectoring Differential
It is the most advanced and technology-based differential in automobiles. The torque-vectoring differential manages the power distribution electronically. Sensors used in this differential detect and assess throttle position, road surface, steering system, etc. After properly understanding, it distributes the torque precisely on left and right wheels with the help of controllers and small clutches.
This way, it delivers a seamless driving experience in all corners, irrespective of road conditions. Mainly the performance-based vehicles are equipped with this torque vectoring differential.
How Does a Differential Work?
The differential works differently while vehicles move in a straight line and when it approaches corners. Here are the working principle of differentials for both these scenarios:
1. Vehicle going straight
When the vehicle moves in a straight line, both wheels on the rear side move with an equal RPM. In this situation, all the gears, ring cage and pinions work as one unit. Axle shafts on both sides of the differential spin at a similar angular speed. As a result, both wheels cover equal distance and go straight.
2. Vehicle approaching a corner
Let’s assume the vehicle takes a left turn. In this situation, the left wheel has to cross a less distance than the right wheel. For this, the differential increases the rotational speed (RPM) of its right wheel to a certain extent and reduces the equivalent RPM of it's left wheel.
A small gear placed inside the differential box rotates in order to change the speed of the large or sun gears attached to both shafts of the axle. When a car is turning leftward, the right sun gear gets more torque to increase its rotation. As a result, the vehicle conveniently bends left.
This way, differentials in automobiles play a significant role in enhancing your vehicle’s performance and control while cornering. It passes the right proportion of rotational speed onto both rear wheels so that your vehicle can go forward and change directions efficiently.