WO-2026095912-A2 - IMPROVEMENT OF COOLING EFFICIENCY OF ELECTRIC MOTORS BY UTILIZING INTERNAL MAGNETIC FIELD AND MAGNETIC FLUIDS

Abstract

The invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, aiming to enhance convective heat transfer for improved cooling performance. In this invention, cooling channels are positioned near the coil windings and stator regions—where heat generation is most intense—by making use of the magnetic field already present within the motor. Magnetic fluids (magnetic liquid metals or magnetic nanofluids) are employed as the coolant, and magnetohydrodynamic (MHD) effects are induced through the Lorentz forces exerted by the magnetic field, which alter the flow velocity profile and enhance convective heat transfer. By this method, while the motor temperature is reduced, its cooling capacity is significantly increased. The invention comprises the components rotor (1), stator (2), shaft (3), coil windings (4), housing (5), magnets (6), and cooling channels (7).

Inventors

• ARSLAN, Berkay
• ERTÜRK, Hakan

Assignees

• BOĞAZİÇİ ÜNİVERSİTESİ

Dates

Publication Date

20260507

Application Date

20251030

Priority Date

20241030

Claims (6)

1. 1. The invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, and it is characterized by the following components: • a rotor (1), which is the rotating part of the motor and converts electrical energy into mechanical energy; • a stator (2), which is the stationary part of the motor that generates a magnetic field to drive the rotor (1); • a shaft (3), which transmits the mechanical energy of the rotor (1) outward and forms the rotating element of the motor; • coil windings (4), which generate a magnetic field and contribute to the operation of the motor; • a housing (5), which protects the internal components of the motor from external factors and ensures operational safety; • magnets (6), located on the stator (2) or rotor (1), which create a magnetic field enabling the motor's rotation; and • cooling channels (7), which provide the flow of the coolant to prevent overheating and transfer heat from the motor to the cooling fluid in this way.
2. 2. According to Claim 1, the invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, and it is characterized in that the cooling channels (7) are positioned near the coil windings (4) and the permanent magnets (6), where heat generation is intense and the magnetic field is strong.
3. 3. According to Claim 1, the invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, and it is characterized in that, in regions where convective heat transfer is intense and magnetic forces are relatively strong, the magnetohydrodynamic (MHD) effect in cooling is achieved by using magnetic fluids— such as magnetic liquid metals (gallium and its alloys, mercury, etc.) or magnetic fluids (magnetic nanofluids or magnetic colloids, etc.)— as the coolant.
4. 4. The invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, and it is characterized in that, in addition to liquid metals, the coolant comprises a base fluid with enhanced electrical conductivity through ionic doping, containing nanoparticles with both thermal and electrical conductivity.
5. 5. According to Claim 4, the invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, and it is characterized in that the base fluid with enhanced electrical conductivity through ionic doping comprises water, ethylene glycol, a water/ethylene glycol mixture, oil, or similar substances.
6. 6. According to Claim 4, the invention relates to the improvement of the cooling efficiency of electric motors by utilizing the internal magnetic field and magnetic fluids, and it is characterized in that the coolant contains one or more types of nanoparticles selected from copper oxide, magnetite ferrite, manganese-zinc ferrite, and nickel-zinc ferrite.

Description

IMPROVEMENT OF COOLING EFFICIENCY OF ELECTRIC MOTORS BY UTILIZING INTERNAL MAGNETIC FIELD AND MAGNETIC FLUIDS Technical Field The invention relates to the improvement of the cooling efficiency of electric motors used in electric land, air, and marine vehicles within the automotive sector, by utilizing the internal magnetic field already existing in the motor itself. This approach enhances the cooling performance of the motor without adversely affecting the vehicle's range and, on the contrary, contributes to extending it. Background of the Invention An electric motor is a machine that converts electrical energy into mechanical energy. Its fundamental operating principle is based on the force generated by the movement of electric current within a magnetic field, which causes a rotor to rotate. These machines are widely used in various fields, such as electric vehicles, household appliances, industrial machinery, and energy systems. Climate change and global warming have led to a significant shift in engineering applications toward technologies aimed at reducing carbon emissions [1]. In recent years, there has been a growing interest in electric vehicles, particularly in the land transportation sector, which accounts for 49% of global fuel consumption [2, 3]. While Andersen et al. demonstrated that the transition from gasoline- powered to electric vehicles could reduce greenhouse gas emissions by up to 20% [4], Endo [5] projected a substantial reduction— up to one-third— in CO2 emissions between 1990 and 2050 through the advancement of electric vehicle technologies. Many governments plan to implement tax regulations to prevent the excessive use of carbon-based fuels in vehicles, thereby encouraging the adoption of electric vehicles. With the increasing prevalence of electric vehicles, electric motors with higher power capacities and longer ranges are being developed each day. A similar situation applies to electric motors used in air and marine vehicles. The rise in motor performance consequently increases the cooling load required for these motors. If the thermal load cannot be adequately dissipated from the system, the efficiency of the electric motor decreases, its service life and durability are reduced, and maintenance costs rise. In currently used electric motors, when heat transfer remains limited, the motor operates at relatively high temperatures. And this may result in a shorter lifespan for the motor, a reduced level of mechanical endurance, and higher level of maintenance expenses. When the motor cannot be effectively cooled, its operating capacity must be reduced to ensure that it functions safely within permissible temperature limits, which in turn negatively affects vehicle performance. The invention titled "ig Rotorlu Elektrik Motoru igin Bir Kanalli SIVI Sogutma Sistemi" with application number 2017/16470, owned by Aselsan Elektronik Sanayi ve Ticaret Anonim §irketi, is considered the closest prior art. However, it differs significantly from the present invention titled "Improvement of Cooling Efficiency of Electric Motors by Utilizing Internal Magnetic Field and Magnetic Fluids." In the invention with application number 2017/16470, cooling is achieved by integrating and positioning cold cooling channels and manifolds within the motor. However, the use of the magnetic field inside the motor or magnetohydrodynamic (MHD) effects has not been considered, which limits the capacity of the cooling system. In that design, the direction of the fluid flow is achieved through the use of inlet and outlet manifolds, channels, and couplings. The invention titled "Versatile Cooling Housing for an Electrical Motor" with publication number EP2879278A1, owned by SKF Magnetic Mechatronics, is considered the second closest prior art. However, it also differs from the invention titled "Improvement of Cooling Efficiency of Electric Motors by Utilizing Internal Magnetic Field and Magnetic Fluids." The invention disclosed in the publication number EP2879278A1 provides effective heat dissipation by using cooling fins and liquid cooling paths. This process is achieved through the use of fins and liquid cooling channels placed on the outer surface of the housing. However, in this invention as well, neither the utilization of the internal magnetic field of the motor nor the application of magnetohydrodynamic (MHD) effects for cooling has been considered. The fundamental methods applied to improve the cooling of electric motors include increasing the flow rate of the coolant, enlarging the surface area where heat transfer occurs, and using coolants with higher thermal conductivity. The increase in the flow rate of the coolant is limited by the flow capacity and power of the pumps or fans used. When a pump or fan with higher power consumption is employed, the required energy is drawn from the vehicle's battery, which consequently reduces the driving range. It is possible to enhance heat transfer by increasing the sur