Scientists invent award winning 2-in-1 motor for electric cars

September 30, 2014
Satheesh Kumar, research scholar from the Energy Research Institute @ NTU holds the modified air-conditioning compressor which is now integrated with the engine of the electric vehicle. Credit: Nanyang Technological University

Scientists from Nanyang Technological University (NTU) and German Aerospace Centre (DLR) have invented a 2-in-1 electric motor which increases the range of electric vehicles.

This innovative engine integrates the traditional electric motor with the air-con compressor, typically two separate units. This novel, space-saving design allows the use of bigger batteries, which can increase the range of electric vehicles by an additional 15 to 20 per cent.

Prof Subodh Mhaisalkar, Executive Director of the Energy Research Institute @ NTU (ERI@N), said: "The biggest challenge with 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."

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.

With the potential boost in range through the efficient use of energy, the joint invention recently won the Best Originality Award in the TECO Green Tech International Contest held in Taiwan.

The competition saw 19 entries from top universities including Boston University, University of California (UCLA), Waseda University, and universities from China and Russia.

NTU's partner, DLR, the German aerospace and space agency will conduct further tests and improvements to the new engine 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.

Prof Mhaisalkar, said this innovation will pave the way for extending the range of electric cars, as the integrated design combines the two of the most important parts of an electric car, thus reducing its complexity into one highly efficient solution.

"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," added Prof Mhaisalkar. "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."

For the automobile manufacturers, 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.

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 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," added Dr Schier.

Research scholar Mr Satheesh Kumar from the Energy Research Institute @ NTU said his award-winning, integrated 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 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."

This research is part of NTU's focus on sustainability research. Sustainable Earth and Innovation are two of NTU's Five Peaks of Excellence, which are areas of research that the university hopes to make its global mark in. The other three peaks are Future Healthcare, New Media, and the Best of East and West.

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3 / 5 (2) Sep 30, 2014
What are they doing about the "Heat"? The electric motor generates heat, the compressor definitely generates heat! So, where's it going?
The regeneration 'extra' is really neat!
1 / 5 (2) Sep 30, 2014
Electric car engine with a belt to a compressor.... There never was such a thing. You make it sound like their doing away with AC compressors in electric cars. Electric cars have electric AC like RV air conditioners.
1 / 5 (2) Sep 30, 2014
I think for the moment, it's better to overcome the cost of range by having car rental places. Most people will not drive more than the maximum allowable range daily, unless they go on a trip or something.
5 / 5 (2) Oct 01, 2014
Does that mean the AC only works when the car is moving at speed, or is there some sort of clutch that allows the motor to spin the compressor and not the wheels?

And is the compressor always running, or is there a second clutch to disengage the AC when it is not needed? Or is there a bypass valve to allow it to freewheel to minimize energy loss?

5 / 5 (3) Oct 01, 2014
AC hasn't worked in my car for years so I've grown used to not having it. Would this design be more efficient than not having AC to being with?
not rated yet Oct 01, 2014
this isn't entirely clear but it sounds like regenerative braking is actually running a pneumatic pump instead of a motor/generator. ---instead of recycling the high pressure air, through a piston back towards the wheels, it is being used as the compressor for the refrigerator pump.

that sounds like a lot of it. that, and perhaps the cars electric motor running both the wheels and the shaft powering the compressor. how the motor can do both at the same time ? maybe there are two separate sprockets on the rotor? one going to the power-train and one going to the compressor.
not rated yet Oct 02, 2014
This does raise the question of what provides the A/C when stopped at lights etc. Even if there was some sort of clutch, what would happen when stuck in creeping traffic where you are moving slowly?
not rated yet Oct 03, 2014
Use an axillary air compression system, as in 'air car' (stored air) attributes to power the air conditioning. The extra mass is almost negligible, as it is not sized to provide motion to the vehicle, just to provide extra power for the AC when it is needed.Charge it at night or when parked, just like the rest of the car's battery systems.

PS, with a small modification, it can also work both ways, it can provide aux electrical power when required and be charged via regenerative braking. The power loss attributes would have to be analysed on the secondary connectivity and disadvantages of mass of said secondary connectivity systems, but in the basic sense, it very likely works efficiently enough.
not rated yet Oct 05, 2014
Use an axillary air compression system, as in 'air car' (stored air) attributes to power the air conditioning.

That makes sense. Whenever I use my canned air to clean dust off things,the can quickly becomes uncomfortably cold in my hand.

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