Promising new engine undergoing further improvements for eventual commercialisation
Who wouldn't like to get 2 for 1? That's probably what scientists from Nanyang Technological University (NTU) and German Aerospace Centre (DLR) thought while developing a new 2-in-1 electric motor for electric cars.
It integrates electric motor with A/C compressor and the compressor drive motor in a single housing. The compressor drive motor is engaged via clutch during braking event, which according to the team will improve overall efficiency, increasing range in hot climates by up to 15-20%.
"The new 2-in-1 design allows the electric motor to be more efficient in powering the car’s wheels, while its integrated air-con compressor uses less power due to synergy between the engine and the compressor, which can also tap on energy regenerated directly from the car’s brakes."
Well, electric cars are typically recovering most energy from braking, so using kinetic energy to propel an A/C compressor will only be slightly more efficient (less energy conversions). We don't think 15-20% range gain is really possible. Maybe 5%?
Moreover, we believe this device has some drawbacks. How will the A/C operate efficiently if we are not braking much?
"Based on simulations and analysis, the team expects the system to reduce battery consumption by at least 3% compared to existing mechanisms while improving the regenerative energy capturing capacity of the system by 8%."
Prof Subodh Mhaisalkar, Executive Director of the Energy Research Institute @ NTU (ERI@N), stated:
“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.”
“With the global population of electric vehicles set grow rapidly to 20 million in 2020, a more efficient electric motor cum air-con compressor, will enable cars to travel further on a single charge. This energy efficiency will in turn reduce overall greenhouse emissions and promote sustainable transportation solutions.”
“This integrated design solution for air conditioning will go a long way in reducing the range anxiety of drivers, reduce maintenance costs, and will save time and money for the driver.”
This work won the Best Originality Award in the TECO Green Tech International Contest held in Taiwan. German Aerospace Centre will conduct further tests and improvements before of eventual commercialization.
Dr Michael Schier, from DLR’s Institute of Vehicle Concepts, remarked:
“For electric vehicles, the air conditioning uses a lot of electrical energy, thereby cutting down the range of electric cars by up to 50 per cent. 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 Mr. Satheesh Kumar from the Energy Research Institute @ NTU said his award-winning, integrated electric motor challenges conventional design that goes way back to the 1960s when air-conditioning first became popular:
“Back then, air-conditioning was something new that was an add-on feature to a car’s combustion engine,” said the 29-year-old Singaporean.
“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 and it also improves engine braking, which stops the car faster with lesser wear on the brake pads.”