The differential is a car component installed at the manufacturing stage to alter the speeds of different wheels serving under one energy source.
When turning a car, the outside wheels need to turn faster than their inside counterparts for the turn to happen effectively. This is the role of the differential system.
So, do electric cars have a differential? Yes, if an electric car is using one mortar to turn all four wheels, then a differential is needed for effective turning.
Contents
What Is Differential?
This is simply a system of gears that affects different speeds on different drive wheels on the same axel. Drive wheels are wheels that receive power directly from the engine. The differential comes into play during turns.
The differential also affects changes in direction for rotating drive shafts.
These components are low maintenance and come all sealed up. Manufacturers expect them to last the car’s lifetime although a few maintenance checks are needed.
Four-wheel drive cars can have multiple differentials due to the added drive wheels.
Signs of a failing differential include vibrations, binding during turns, and clunking.
Do Electric Cars Have Differential Installed?
All-electric cars using one mortar to turn the drive wheels must have differential systems. There are some electric cars however that come with independent mortars for each drive wheel. The independent mortars’ speed is configured to vary in respect to each other during turning.
If the car is 4WD it comes with four mortars that are completely independent of each other. The front-wheel mortars will be set to drive different speeds when turning. This is achieved through pulse width modulation or variable frequency.
The concept employed when implementing a differential for DC mortars is called an electronic differential. In the case of AC mortars, it’s called an electric differential. To eliminate mechanical overhead or employ in-wheel motors, differential equations are derived.
Types Of Differentials
Open Differential
Aside from being the oldest on the list, it is the most common in modern cars. It employs a simple but practical design that makes installation and repair much easier. Almost all high mileage cars have this differential.
The driveshaft has a powered pinion gear at the end that engages with the ring gear. The generated power is transmitted to the axel through a separate set of gears.
One malady ails it however, when one wheel experiences slip, the excess power is offloaded on the wheel with the least traction. This design makes the system impractical for high-speed driving.
Limited-Slip
It is in several aspects similar to open differential except for the fact that it utilizes an integrated clutch system. In a scenario where a wheel loses traction, the system locks both the left and right sides of the axel. High-performance cars and tow trucks have this system.
Torque-Vectoring
This is the most recent development in automotive differential technology. This differential system collects complex data from various parts of the vehicle and uses it to determine the side to send more power.
The data collection concentrates on the steering wheel, road surface, and throttle position using special sensors within the system. The power distribution technique ensures just enough traction for each wheel during cornering-this greatly improves performance.
How To Take Care Of The Differential?
There is a belief that differential systems last the car’s lifetime. This might be true but it does not rule out the need for routine servicing of the car’s different parts.
The system uses lubrication oil which might need changing once in a while. The oil works more like engine oil to protect the differential and allow for smooth and safe functioning.
As time goes by, the fluid might get contaminated and need changing. Driving with the spent fluid will wear out other vital components whose repairs might not be so cheap.
The Signs Of Failing Differential System
- Whirling sounds when reducing speed
- Whining upon acceleration under both low and high speeds.
- Rumbling when driving at speeds not exceeding 20mph. The sounds might stop when the car changes direction.
- Interval clunking sounds when accelerating
- Sudden vibrations when at high speeds.
Conclusion
Different electric cars manufacturers employ different designs in the power transmission systems. The bottom line is: every electric car with one power source must have a differential system to alter the speeds of the different wheels during turns.
