How BLDC/PMSM Electric Motors are Making Manual Interventions Obsolete in your Automobiles
If you are a 90’s kid or had the fortune of buying a car during those times, you must have memories of using handles for operating the windows. Locking the car doors manually using a key was also a very common practice.
Such manual interventions for simple operations were standard operating procedures in passenger as well as commercial vehicles.
An “Electric Motor” justified the true meaning of the name “Motor Car”. Initially, the application of these motors did not have any direct impact on the ride quality (EVs changed that too), but it definitely took the driving experience a few notches higher.
Having said that, we should also clarify that the automotive industry did not adopt electric motors overnight.
The evolution of electric motor happened in hands and arms with the evolution of automobiles and the gradually maturing expectations of the end-users.
The OEMs and other stakeholders of the automotive industry spent a lot of sweat and blood (and lots of moolah) in order to fuel innovations in motor-control solutions & systems, in order to leverage the full potential of electric motors
Despite being an omnipresent part of an automobile, these motors are always hidden inside the hood and never get the recognition they deserve.
In this blog, we try to turn the spotlight on the electric motors in your car and how they are hard at work to make all your manual interventions obsolete!
P.S – We are not hinting at Man v/s Machine Conflict here. So just relax
But where are all these omnipresent motors in my car, I don’t see any?
They are present in more places than you can imagine!
- When you turn the power steering, an electric motor assists you.
- When you apply the car brakes, an intelligent motor fitted inside the Anti-lock Braking System makes sure that the brakes are applied efficiently without causing any skid.
- And the list can get never ending
Let’s learn about some of these applications in detail!
Electric Power Steering (EPS)
If you have ever driven a manual steering car, you would know how difficult it is to operate.
The manual steering system is responsible for converting the rotation of the steering wheel into a swiveling motion of the vehicle’s wheels. This system enables a driver to use relatively light forces to steer a vehicle.
However, when maneuvering a heavy vehicle, either the steering will be heavy or low geared. The driver is hence, required to turn the steering wheel from lock to lock several times in order to steer the vehicle.
An Electronic Power Steering (EPS) system puts an end to these issues by engaging a motor for steering control.
How Does Electric Power Steering Work?
In an EPS steering system, the steering assist is usually provided by a bidirectional brushless DC motor, electronic controller and sensors. The motor drives a gear that is connected to a steering column shaft.
Sensors in the steering column receive two primary inputs from the driver, i.e., the steering effort (torque) and the speed/position of the steering wheel. The measured speed, torque, position and vehicle speed, along with other inputs are processed by the electronic control module.
The processing of the controller is through a series of algorithms. The right amount of polarity and current is, hence, provided to the motor.
It should be noted that the engine speed and chassis control systems are other inputs that affect the steering assist.
What are the Advantages of Electric Power Steering?
- Electric Power Steering reduces cost by eliminating steering pumps, hoses, drive belts and hydraulic components from the engine.
- EPS is energy efficient as it uses lesser battery resources than manual steering.
- It is easy for OEMs to pack and tune the electric power steering when compared to a hydraulics system of power steering.
- Electric Power Steering is easy to maintain as lesser number of components are required to operate it.
- Electric systems have much more simple setups and hence, the weight over the front axle is reduced.
- In performance cars, electric power steering enables more flexibility as far as steering modes are concerned. So, the steering may feel heavier in Sports mode and lighter in Comfort mode.
Power Window is a simple, yet critical application of motors in a vehicle. In contrast to an EPS where an electronic motor control system is used, a power window is controlled electrically.
How Do Power Windows Work?
Power windows are operated with switches and wires connected to a motor fitted to the window. The system is powered by the vehicle’s battery and hence, is available only when the ignition is switched on.
The switch controlling the power windows is a two-way variant and goes up and down. When the user pulls it up, it sends an electrical signal to the battery, which in turn, sends the signal to the corresponding motor.
With advancements in automotive electronics, the power window along with power doors and Outside Rear View Mirrors (ORVMs) have been connected and operated using a central system, usually referred to as Body Control Module.
Advantages of Power Windows
- Power Window is more of a comfort-oriented feature but an important one, as it gives the driver the ability to control all the windows without leaving his/her seat.
- An individual who is not in good physical condition, such as a person with a hand injury, can also operate a power window effortlessly.
Heating, Ventilation and Air Conditioning (HVAC) Systems have become an integral part of motor vehicles. However, that was not always the case. It was only in the 80’s that air-conditioning systems started making their presence felt in the automotive industry.
How an HVAC System Works
An electric motor has a very crucial role to play in such systems.
- Heater System – The motor regulates the air movement by pulling air from the outside and centrifuging it over the fins of a radiator. The engine coolant is circulated through the radiator core. This quick movement of air propelled by high-power motors helps in achieving the heating.
- Air Conditioning – The air conditioning system primarily consists of the following parts:
- Expansion Valve
The refrigerant is compressed and turned into a hot gas in the compressor. This gas is converted into a liquid state in the condenser and it moves into the expansion valve. As the refrigerant passes through the expansion valve, it becomes a low-pressure gas and is cooled in the evaporator.
The cold low-pressure refrigerant is moved into the evaporator where it vaporises. It absorbs heat from the air in the passenger compartment. The blower fan is responsible for pushing the air over the evaporator fins so that the cold air is circulated in the passenger compartment.
In modern HVAC systems, the motors are controlled by Pulse Width Modulation (PWM) signals generated by Motor Control Systems. Due to this, the motor can have infinite levels of fan speed, which means that specific temperatures can be achieved. An example of such HVAC system is the Climate Control System in automobiles.
HVAC system is aimed at making the drive more comfortable in extreme summers and winter season.
Anti-lock Braking System (ABS)
The concern towards automotive safety has been on a rise, thanks to strict regulations in the automotive industry.
Anti-lock Braking System is a primary safety component of a vehicle. It prevents the wheels of the vehicle from locking up and enables drivers to maintain steering control.
ABS basically assists in maintaining tractive contact of the vehicle wheels with the ground, so that there is no uncontrollable skid. This is particularly helpful in situations of sudden braking.
With the help of wheel sensors, on-board computer (ECU) and an ABS motor, brakes are applied to all four wheels in a controlled way, so that the vehicle is as stable as possible.
If there is one application of motors which has had the most powerful impact, it is the Anti-lock Braking System!
How Does Anti-lock Braking System Work?
An ABS comprises of Wheel Sensors, ABS ECU and ABS motor as the major components. In case of a panic braking, the wheel sensors read the difference in the speed of the wheels and send a signal to the ECU.
The control unit calculates the torque and signals the ABS motors to apply appropriate braking on all four wheels so that they don’t skid.
The ABS motor has solenoids that connect to the brake valves and achieve the desired braking.
Advantages of Anti-lock Braking System
- ABS is a proven braking method that ensures safety of the vehicle when sudden brake is applied on slippery surfaces.
- Its importance can be gauged by the fact that it has been made compulsory in both four-wheelers and two-wheelers in many countries.
And More to Come!
In addition to the applications we discussed in this blog, there are many more ways in which electric motors are being utilized by the automotive industry.
This includes seating control and comfort systems, sunroof control systems, and more
The motors assume even more importance in an electric vehicle where they are also responsible for driving the entire vehicle.
If the pace of innovations in motor control technology is anything to go by, we can expect even more astonishing ways in which motors will replace manual interventions in an automobile.
Beware! Machines (Electric Motors) are coming…..to make your Driving more comfortable. So please don’t get paranoid.