Kia EV9’s Motor Does The Electrical Equal Of Shifting Gears

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A current article at The Autopian raised an fascinating level concerning the Kia EV9’s electrical motor. In contrast to most electrical motors, it will possibly change its winding configuration on the fly, successfully doing the identical factor as shifting gears in an ICE car. However, to clarify how wonderful this know-how is, we have to first clarify what transmissions in ICE autos (and a few EVs) do.

Why ICE Autos (& Some EVs) Have Transmissions

If you already know so much about combustion engines, transmissions, rear-ends, and wheel sizes, you’ll be able to in all probability skip this part. For everybody else, I’m going to clarify within the easiest phrases attainable what a transmission does in order that we are able to evaluate it to what Kia’s electrical motor does.

In brief, an ICE car’s engine isn’t like an electrical motor the place you have got instantaneous torque out there proper from the get-go at zero RPM. An ICE doesn’t even work at zero RPM, and has to idle when the automotive stops to forestall stalling out. At actually low or excessive RPMs, combustion engines should work inside a reasonably slender band of effectivity, also known as the “energy band.” Consider it like pedaling a motorbike with just one gear ratio; you’d battle to begin shifting, and when you’re shifting, you’d both spin out if the gear is simply too low, otherwise you’d barely transfer if it’s too excessive. An ICE that’s at too low of an RPM will battle to maintain operating or get broken.

That is the place the transmission is available in. It’s just like the a number of gears in your bike, permitting the engine to function in its best vary whereas the automotive can go from standstill to freeway speeds. By having plenty of gears to select from, the combustion engine can at all times be inside the vary of speeds the place it’s pleased and doesn’t break.

However, to get the very best efficiency and gasoline mileage, ICE autos are beginning to include an increasing number of gears. Fashionable engines do have some flexibility when it comes to very best RPM as a consequence of applied sciences like variable valve timing, however getting the entire symphony of pistons, rods, crank, cams, lifters, and injectors to all harmonize across the objective of creating energy or getting good mileage is so much simpler if you could find the appropriate tempo.

Some have as many as ten speeds in order that the engine may be not simply in a cheerful vary, however fairly near the perfect RPM. However, with all of those further gears comes further elements that may break, finally reaching the purpose of diminishing returns for upkeep, reliability, and value of operation.

Some Electrical Autos Have Transmissions, & For Related Causes

The common EV nerd who isn’t conversant in automotive know-how will let you know that EVs don’t want a transmission. The only-speed gear reducer does the job fairly properly as a result of trendy electrical motors work properly throughout a really big selection of speeds. They’ll work from zero RPM to properly over 10,000 RPM with out taking harm. Mechanically talking, they’re actually easy, and have solely two shifting elements (the rotor and the stator), so there isn’t a fancy symphony to search out the proper tempo for.

However, an electrical motor’s versatility and adaptability doesn’t imply that it’s acquired the identical energy and effectivity throughout its whole vary of RPMs and pedal positions (torque). There are specific torque and RPM conditions the place an EV’s motor makes energy much more effectively than others, offering for higher vary. There are additionally RPMs and torque conditions the place the motor tends to carry out higher than others.

Because of this, there’s actually no cause EVs can’t profit from a transmission. Some automakers put easy 2-speed transmissions in manufacturing EVs (the Porsche Taycan is an efficient instance), and other people changing ICE autos to electrical have usually mounted an electrical motor as much as a handbook transmission. Jeep has even constructed some electrical car prototypes with handbook transmissions, which might be enjoyable for fanatics.

The true cause most EVs don’t do that isn’t that it wouldn’t be good. It’s extra about value financial savings and holding issues easy. Automakers constructing EVs with a number of drive models have even managed to offer the advantages of a transmission by giving the entrance motor a distinct gear ratio than the rear one, after which having the pc “shift” between the motors to get higher vary in several conditions. So, the necessity to have the ability to “shift” may be very actual, even for Tesla.

Kia’s Motor Can Shift Its Effectivity Curve With out A Transmission Or A number of Drive Models

Kia managed to discover a inventive workaround for the necessity to shift RPMs to maintain the electrical motor in a velocity vary the place it will get probably the most effectivity. And the corporate’s engineers did it with out including in any further shifting elements, like gears or extra drive models.

You must learn the entire article at The Autopian if you need full particulars, however in brief, Kia’s motor is like two motors in a single. Ship the facility into one set of wires, and a you have got a “wye” motor. Ship the facility into a distinct set of wires, and you’ve got a “delta” motor. In brief, the wye configuration tends to work higher at low speeds, whereas the delta configuration is healthier for increased car speeds. It implies that one motor can behave like two completely totally different motors with out the price of an additional drive unit, further gears, or anything.

“Shifting” the EV9’s motor is fairly easy: the car’s laptop sends the facility down totally different wires. Not solely would a driver not want to consider it, they’d in all probability not discover in any respect. Throughout my week with an EV9 press car, I had no thought something was occurring to ship higher efficiency or vary. It occurs at about 45 miles per hour, with no indication, controls, or shift shock.

The additional benefit is that, just like the Hyundai Ioniq 5 (made by the identical producer), the motor can be used to transform 400 volt charging to increased voltages to cost the car quicker.

This idea of shifting between totally different modes has been round for industrial motors for a very long time, however till not too long ago, they weren’t very cost-effective to do in EVs. By working with the appropriate suppliers and making the most of reducing semiconductor prices, Kia has managed to convey the idea to the EV world and make it work even higher.

Featured picture by Jennifer Sensiba.