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Singaporean and German engineers have developed a “2-in-1” electric motor they say will extend the range of electric vehicles by up to 20% and increase their use in tropical cities.
The motor integrates an electric motor with the air conditioning compressor, typically two separate units. This saves space to enable the use of larger batteries, which can increase the range of electric vehicles by an additional 15 to 20%.
Professor Subodh Mhaisalkar, executive director of the Energy Research Institute at Nanyang Technical University, said: “The biggest challenge with electric cars in tropical megacities is the range that they can travel on a full-charge, because their batteries are needed to power both the engine and the air-conditioning. In tropical countries like Singapore, up to half the battery’s capacity is used to power the air-conditioning system.”
Researchers from Nanyang Technological University (NTU) and German Aerospace Centre (DLR) aimed to improve the efficiency of the motor and integrated the air conditioning compressor to reduce the amount of power it uses. Integrating the motor and air-conditioining also enables the compressor to use energy regenerated directly from the car's brakes.
He added that the new electric motor will also cost less to produce, as it requires less material than its counterparts. Both the weight and size of the electric motor are reduced, creating more space for other components such as an auxiliary battery source.
DLR, the German aerospace and space agency, are conducting further tests and improvements to the new device with the aim of eventual commercialisation. The team is applying for a Proof-Of-Concept (POC) grant in Singapore. After the development of the prototype, test bedding and refinements will be done at DLR’s facilities in Germany.
Dr Michael Schier, from DLR’s Institute of Vehicle Concepts, said: “For electric vehicles, the air conditioning uses a lot of electrical energy, thereby cutting down the range of electric cars by up to 50%. To increase the energy efficiency and therefore the range of electric cars, the thermal management and the integration of additional functions into existing powertrain components play a major role.
“By integrating the refrigerant compressor directly into the electric motor, we save components, weight and cost. Simultaneously, the more regenerative braking part of the kinetic energy is passed directly to the refrigerant compressor and thus the efficiency is further increased.”
Research scholar Satheesh Kumar from Nanyang University said the integrated electric motor challenges conventional design that goes way back to the 1960s when air-conditioning first became popular. He said: “Back then, air-conditioning was something new that was an add-on feature to a car’s combustion engine.
“Since we are now designing electric vehicles from scratch, I see no reason why we should keep both units separate. As we have proven, combining the two gives us synergy – a more efficient use of electricity . It also improves engine braking, which stops the car faster with lesser wear on the brake pads.”