What you should know about the engine of electric cars

What is the engine of an electric car made of?

A motor for an electric car consists mainly of a rotor and a stator. The rotor is the moving part of the motor and usually consists of a magnetic core surrounded by coils of copper wire.

The stator, on the other hand, is the fixed part of the motor that surrounds the rotor and is also made up of copper wire coils arranged around the rotor.

To regulate the speed and torque of the motor, an electronic switch or regulator is used that adjusts the amount of current supplied to the stator coils.

The housing, which forms the external structure of the engine, houses all internal components and protects the motor from external influences.

Depending on the cooling needs, some electric motors may be equipped with cooling systems such as radiators or fans to dissipate the heat generated during operation.

What is the difference between an internal combustion engine and an electric motor?

The difference between an internal combustion engine and an electric motor in an electric car is that the internal combustion engine in an electric car is not connected to the electric motor. Electric car lies in the way they work and the energy source they use.

• Internal combustion engine:
  
  
• The internal combustion engine converts thermal energy into mechanical energy.
• It works by burning fuel (gasoline or diesel) in the cylinders.
• Internal combustion engines have a maximum speed, which is usually below 8000 rpm.
• They have a high power and torque range, but only in a small speed range.
• They generate noise and vibrations when they are in operation.
• Maintenance is more complex due to the delicate mechanical parts and the fluids (oil, fuel) that need to be managed..

• Electric motor:
  
  
• The electric motor converts electrical energy into mechanical energy and vice versa.
• It works through the electromagnetic force generated by magnets.
• There are three types of electric motors: direct current, synchronous alternating current, and asynchronous alternating current.
• The electric motors can reach high speeds, sometimes up to 16,000 rpm, while maintaining a good level of torque and power throughout the range.
• They are quiet, require little maintenance and have fewer sensitive mechanical parts.
• Electric cars use DC or AC motors.
  
  

Essentially, the internal combustion engine uses the combustion of fuel, while the electric motor is powered by electricity.

The electric cars prefer electric motors because of their efficiency, low noise and ease of maintenance.

How does an electric motor work in an electric vehicle?

An electric motor in an electric vehicle works by converting the electrical energy stored in the vehicle's battery into mechanical motion to drive the wheels. The electric motor in an electric vehicle works in the following steps:

1. Electrical power supply Electricity: The electricity is supplied by the vehicle battery. The battery usually stores electricity in the form of direct current (DC), but it can also be used to store alternating current (AC), depending on the system design.
   
   
2. Conversion to alternating current When the battery provides power in the form of direct current (DC), a direct-to-alternating current (DC-CA) converter is used to convert the current to alternating current (AC). Most electric motors use alternating current to operate.
   
   
3. Activation of the motor Once the electricity has been converted into alternating current, it is transmitted to the electric motor. The motor is equipped with copper wire coils arranged around a stator and a rotor, which is usually made up of permanent magnets. When alternating current is applied to the stator coils, this creates a rotating magnetic field.
   
   
4. Rotation of the rotor The rotating magnetic field induces a magnetic force in the rotor that causes it to rotate. This rotary motion is transmitted to the wheels of the vehicle via a suitable transmission system, such as a differential and a drive shaft, which ultimately propels the vehicle forward.
   
   
5. Control of speed and torque Electronic control: The electric motor can be controlled electronically to adjust the speed of the rotor and the torque generated. This allows the performance of the vehicle to be optimized under various driving conditions such as acceleration, braking, and cruising speed.

Electric car engine: what are the benefits?

Energy performance and efficiency

Electric car engines offer a number of advantages in terms of performance and energy efficiency compared to traditional combustion engines. Here are some of these benefits:

• High energy efficiency Electric motors convert a larger proportion of electrical energy into motion than internal combustion engines, which dissipate a large part of the energy in the form of heat.
• Instantaneous torque Electric motors produce maximum torque immediately after starting, providing fast and fluid acceleration without the need for a ramp-up time like internal combustion engines.

• Fast Response: Electric motors respond quickly to commands, resulting in a better driving experience and an instant response of the accelerator pedal.
  
  

• Less maintenance Electric motors have fewer moving parts and fewer components that are prone to wear than internal combustion engines, which reduces the need for maintenance and the associated costs.
  
  

• Electric motors are much quieter than internal combustion engines, which allows for a smoother driving experience and reduces noise pollution.
  
  

• No local emissions that help improve air quality in urban areas and reduce the globalcarbon footprint, especially when powered by renewable energy sources.
  
  

• Braking energy regeneration Brake energy recovery systems convert some of the vehicle's kinetic energy into electrical energy that can be fed back into the battery and increase theoverall range of the vehicle.
  
  

• Flexibility in design Electric motors are more compact and can be arranged more flexibly in a vehicle, giving designers more freedom to design innovative interiors and optimize available space.
  
  
  

Fewer moving parts

With fewer moving parts than internal combustion engines, electric car engines offer greater reliability, less maintenance, simpler design, and a quieter driving experience.

By eliminating the complexity of piston and valve systems, electric cars benefit from a more efficient and sustainable alternative for vehicle propulsion.

Longevity of the electric battery

The battery life of an electric vehicle motor depends on several factors, including battery technology, charging conditions, driving habits, and maintenance. Modern lithium-ion batteries are designed to last for several years with proper use and maintenance, and are often covered by warranties of up to 8 years or 160,000 kilometers.

Manufacturers and drivers can adopt practices to extend battery life, such as avoiding repeated full charge cycles and maintaining an optimal state of charge.

In the event of battery deterioration, certain replacement or repair options may extend the useful life of the electric vehicle.

What to read: Range, performance, battery: How does an electric car work?

What are the different types of motors for electric cars?

Motors

Direct current electric motors (DC motors) are electrical machines that convert electrical energy into mechanical energy. They are powered by a DC power source, such as a battery or rectifier. DC motors are used in a wide range of applications, from small electronic devices to large electric vehicles.

The functional principle of a DC motor is based on the interaction between a magnetic field and a current-carrying conductor. The magnetic field is generated by permanent magnets or electromagnets.

The current-carrying conductor is usually wound around a soft iron core. When current flows through the conductor, it creates a magnetic field that interacts with the magnetic field generated by the permanent magnets or electromagnets. This interaction generates a force that causes the rotor of the motor to rotate.

AC motors

New developments in power electronics have facilitated the integration of AC motors in electric vehicles. In order to efficiently supply asynchronous and synchronous motors, a system must now contain a three-phase inverter between the battery and the motor. This inverter must be able to switch the electricity in both directions, so that the machine can operate in generator mode when decelerating.

To control these motors, two key parameters must be regulated: the voltage and the frequency of the AC signal supplied by the inverter. To adjust the frequency, the six switches must be controlled with a variable frequency. As for the voltage, the inverter must also include a pulse width modulation (PWM) function to regulate it effectively.

The variable reluctance motor

This motor is based on the reluctance principle with a rotor consisting only of sheet metal and windings located on the stator. The main advantage of this type of motor is the low rotor losses, low induced current and relatively low bearing temperatures.

However, despite its attractiveness in terms of cost and ease of manufacture, this motor presents challenges, especially in terms of complex control, non-sinusoidal currents, small air gap and specific inverter structure (4 or 6 phase) typical of this technology. In addition, problems such as how to deal with the noise generated and the large torque fluctuations at low speeds must be taken into account.

The asynchronous motor

In this type of motor, the stator is supplied with sinusoidal three-phase currents that generate a rotating magnetic field. This magnetic field induces currents in the rotor, causing it to rotate at a speed slightly lower than that of the rotating stator magnetic field. The speed difference between these two elements is called slippage and represents the main weakness of asynchronous motors: the greater this difference, the lower the efficiency of the motor.

This type of motor works without brushes and magnets and is equipped with a speed sensor. Although the torque dynamics are lower than on a machine with magnets, control is simpler than on synchronous machines. Asynchronous motors have good efficiency at low load, but require a small air gap, which makes them unsuitable for use in wheel motors. They produce significant losses at high torques and low speeds (due to the magnetization of the rotor) and tend to be bulkier and heavier than magnetic machines.

The synchronous motor

Synchronous motors, which are characterized by zero slip, are currently attracting the attention of electric vehicle manufacturers because they offer higher performance in terms of torque-to-weight ratio, power density, and efficiency. These motors are divided into two main categories: wound motors and permanent magnet motors.

The wound synchronous motor uses a rotor winding to generate the magnetic field and provides a torque density similar to that of asynchronous motors. Control is simpler than permanent magnet motors because the rotor field is controlled by a low-power electronic controller and brushes that conduct current to the rotor. Although it has low partial load losses and good efficiency at high loads, it takes up more space and offers lower torque dynamics than magnetic motors.

In contrast, permanent magnet synchronous motors do not require a rotor winding, which makes them lighter and free of joule losses on the rotor, as the losses on the stator can be dissipated more easily. These motors offer maximum mass torque for radial flow machines, high torque dynamics and a very fast response time.

However, their control is more complex with sinusoidal currents and a position sensor, and they exhibit significant losses at partial load and high speeds. Their cost is also higher due to the NdFeB magnets, which account for about 30% of the total manufacturing cost.

Comparison Table of Different Types of Electric Motors

Inference

In summary, electric motors are revolutionizing automotive mobility due to their efficiency, sustainability and lower environmental impact.

With continuous innovation and the support of electric mobility experts like Beev, the future will begin for you.The future promises electric vehicles. and be more sustainable.

Are you ready to switch to electric driving? Contact Beev today to learn more!