Electric cars do not have pistons, unlike traditional internal combustion engines. They use electric motors operating on electromagnetism principles, consisting mainly of a stator and a rotor.
The power for these motors comes from battery packs, typically lithium-ion, controlled by a system that regulates power based on the driver’s input.
This design leads to fewer moving parts, less maintenance, quick acceleration, and zero tailpipe emissions.
We are so used to our cars having pistons and other components that require oil lubrication for the car to work; it’s natural to wonder what an electric car has and how it moves.
What is a piston?
A piston, crucial in a cylindrical engine, moves within the cylinder, driving the engine. It responds to combustion or compression forces, propelling the vehicle. The crankshaft converts these forces from linear to rotational motion, powering the engine.
What Do Electric Cars Use Instead Of Pistons?
Instead of pistons or a traditional cylindrical engine, an electric car has an electric motor. It works using copper coils and magnets that start the engine and allow the car to move.
Electric motors are possible thanks to Nikolas Tesla, who created the induction motor, which has become an industry standard in electric cars.
Fundamentals of Electric Cars
EVs are a complete departure from conventional combustion-engine cars, relying on an entirely different set of components for their operation.
Basic Components of Electric Vehicles
An electric car primarily uses an electric motor for propulsion instead of an internal combustion engine. This motor is powered by batteries which store electrical energy. Key components in the electric powertrain include:
⚡ Electric Motor(s): Converts electricity into mechanical power to drive the wheels.
🔋 Batteries: Store and provide the electrical energy needed by the motor.
🎛️ Power Electronics Controller: Manages the flow of electrical energy delivered by the battery, controlling the speed and torque of the motor.
🌡️ Thermal System (cooling): Maintains the optimal temperature range for the vehicle’s battery and electronics.
⚙️ Transmission: Although simpler than in combustion vehicles, the transmission in an EV still transfers mechanical power from the electric motor to the drive wheels.
Difference Between Electric and Combustion Engines
The fundamental difference between electric motors and internal combustion engines (ICEs) lies in their respective sources of energy and their emissions. The ICE uses the combustion of fuel to create motion, whereas the electric motor uses electric powertrain technology.
- Combustion Engines: Require gasoline or diesel to run and produce emissions from fuel burning, including CO2 and other harmful gases.
- Electric Motors: Powered by electricity from batteries, resulting in zero tailpipe emissions.
You’ll notice the operation of an EV is generally quieter and smoother due to the lack of internal combustion, meaning fewer vibrations and engine noise.
Moreover, the instant torque generated by electric motors provides a responsive acceleration experience, which is distinctive from the gradual power build-up in combustion engines.
Electric Vehicle Technology
A shift from traditional engines, EVs use electric motors for propulsion, advanced batteries for energy storage, and regenerative braking to recapture kinetic energy.
Electric Motors and How They Work
Your car’s motor converts electrical energy into mechanical energy. This process doesn’t require pistons or combustion.
Instead, the motor’s rotor is surrounded by a magnetic field created by electromagnets within the stator.
When an electric current passes through, this magnetic field induces torque on the rotor, causing it to turn.
The amount of power and acceleration you feel in an electric vehicle comes down to the motor’s size, the magnetic field strength, and the frequency of the three-phase alternating current supplied by the inverter.
The stator is the stationary part of an induction motor made with high-grade alloy steel lamination to reduce current losses. It features the outer frame, stator core, and stator winding.
The stator core carries an alternating magnetic flux that reduces hysteresis, and the stator winding features a three-phase winding. These induction motors allow the speed to depend on the frequency of the three-phase supply.
Next up, we have the rotor, which is the rotating part of an induction motor. The current is induced by transformer action from the rotating magnetic field and features the same durable construction as the stator.
The rotor is essentially a collection of laminated conducting bars short-circuited by end rings. Depending on the engine, the rotor is either a wound or squirrel-cage type. These induction motors are cost-effective and reliable, making them a fantastic fit for electric cars.
Their brushless design also makes these motors incredibly low-maintenance, with far fewer parts than a piston motor. And with fewer parts, there are fewer parts to break, meaning fewer repairs (hopefully)!
So that’s the engine, but what gives it power?
The battery pack (often composed of lithium-ion cells) is at the heart of your electric vehicle. These batteries store electrical energy that powers the motor.
Battery technology is crucial because it determines the vehicle’s range and how quickly it can accelerate.
Manufacturers work to make batteries that can hold more charge while keeping heat generation to a minimum, as excessive heat can degrade the battery’s lifespan and performance.
Regenerative Braking Systems
When you apply the brakes in your electric vehicle, your motor doesn’t just stop; it goes into reverse.
This is part of the regenerative braking system, which transforms the kinetic energy usually lost as heat during conventional braking into electrical energy.
This energy is then sent back to the battery pack. Not only does this system conserve energy, but it also reduces wear and tear on your brakes, making it a dual advantage of electric vehicle technology.
Electric Vehicle Design Considerations
Your electric vehicle is designed with a focus on simplification and efficiency. With no need for pistons, a fuel tank, or a complex exhaust system, the design can prioritize other components, like the battery and the electric motor.
A key design consideration is the placement and size of the battery pack, which predominantly determines the vehicle’s range and balance.
The absence of a bulky engine block affords designers more freedom, often resulting in spacious interiors and innovative storage solutions.
Without a conventional gearbox, your EV relies on the electric motor’s inherent ability to generate rotational force effectively from zero RPM, ensuring immediate response when you press the accelerator pedal.
Performance and Efficiency
One of the most distinguishing features is the consistent and linear power delivery: when you press down on the accelerator pedal, power is delivered virtually instantaneously, as there’s no need for revving up as in a traditional petrol car.
Efficiency is where electric vehicles truly shine. They convert over 77% of the electrical energy from the grid to power the wheels, compared to conventional gas-powered engines, which convert only about 12-30% of the energy stored in gasoline to power the wheels.
This remarkable efficiency means that your electric vehicle is still a more reliable and environmentally friendly performer on the road even when accounting for electricity potentially generated from non-renewable sources.