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Inmotive introduces efficient two-speed transmission for EVs

Inmotive, a Canadian-based automotive supplier, has launched its patented Ingear two-speed transmission. Invented and designed for the next generation of electric vehicles, the Ingear features a simple and durable design that enables a more efficient powertrain, with extended range, at lower cost.

Inmotive recently completed its extensive pre-production testing of the Ingear, has integrated it into a demonstration vehicle and is ready for full market implementation. Test units are available to qualified OEMs.

Currently, most EVs use single-speed transmissions, however, equipping an EV with an Ingear transmission lowers cost, extends range and improves acceleration times, highway passing capability, top-speed and gradeability, the company said.

Typically, there are two reduction gears between the electric motor and the wheels, with the motor turning about nine times for each revolution of the wheels. The Ingear replaces the second reduction gear with a continuous chain drive and a morphing sprocket that resizes during a shift. The entire shift happens during a single revolution of the wheels.

To shift, an actuator directs sprocket segments into place during a single revolution of the wheels, effectively increasing or decreasing the gear ratio. The Ingear’s patented geometry keeps the motor and wheels in sync, enabling continuous torque flow throughout the shift process. Shifts can be completed in as little as 19 milliseconds.

By enabling the drivetrain to operate more efficiently with low- and high-gear ability, less energy is wasted resulting in more range from each charge. Similarly, regeneration is improved and is continuous, even while downshifting.

Ingear+Rendered+-+Core+Unit+-+View+1

Ingear core unit.


Compared to AMTs, DCTs, and CVTs:

  • The Ingear has no clutch.

  • The Ingear does not require a high pressure pump.

  • The Ingear uses ball bearings instead of roller bearings as it does not generate axial loading from chain/sprocket meshing.

  • The Ingear has no losses from multiple gear pairs engaged simultaneously, nor rolling contact losses.

  • The Ingear does not generate heat due to losses or clutch friction, or rolling contact friction, so motor thermal rise is mitigated without introducing any load on the cooling system.

  • The Ingear offers uninterrupted torque transfer during the shift.

  • The Ingear has consistent/repeatable shifts by design. Other systems require closed loop control that adapts to wear and clutch performance.

  • The Ingear only moves segments axially when they are not contacted by the chain. Actuator force is low. DCTs and CVTs require tens of thousands of newtons of force to shift because the actuators must modulate the traction motor force to the wheels.

We’ve found that today’s automatic transmissions fall short of what the EV industry needs. This next-generation transmission offers an entirely new way of looking at multi-speed transmissions for electric vehicles and extends significant benefits to a wide range of other market segments as well. It is the first two-speed transmission of its kind to be effectively ready for global market adoption.

—Paul Bottero, CEO, Inmotive

Key benefits of the new Ingear transmission include:

  • Cost Saving. By integrating the simple and low-component-count Ingear into high volume integrated drive units, OEMs can save more than $1,500 per passenger vehicle. This savings is possible through using less battery and less expensive electric motors and inverters all while maintaining the same range and improving acceleration. In addition to OEM savings, fleet owners will save about $2,000 in operating (electricity) costs over three years.

  • Compact. Designed to wrap around the differential, the Ingear is only slightly larger than a typical single speed transmission.

  • Quick, smooth and quiet. The Ingear shifts in less than a single revolution of the wheels. The motor is kept in constant contact with the wheels and can continuously apply torque even during the shift. Gear ratios change gradually and torque fill algorithms maintain a smooth passenger experience. Acceleration times can be improved by up to 15%.

  • Efficient and reliable. The Ingear extends the range of a typical vehicle by up to 15% by optimizing motor efficiency and reducing parasitic losses. It also improves towing, hill-climbing and top-speed.

Simulation+Results+Table

Ingear Matlab simulation results relative to default Matlab EV.


Ingear is not a “one size fits all” technology. Its design flexibility enables OEMs to customize the size and scale of the technology based on the specific vehicle type. While initial development has focused on the passenger car market, the technology can be adapted for a wide range of vehicles, including commercial, off-highway and fuel cell applications.

Inmotive currently has development contracts with two global OEMs and is in discussion with several other OEMs from around the world for implementation.

Comments

mahonj

Cool, if it works out.

Nick Lyons

Very clever design--eliminating a helical gearset with its axial thrust has got to improve efficiency. I wonder about wear/longevity of those sliding segments. Wish them luck--lowering motor speed for highway driving should be great for increased range.

Arnold Garnsey

The advantages are compelling. This design reminds me of derailleur with the chain tensioner and the bending of the chain as it accommodates the adjacent gear position.
The sequence of moves happens blindingly fast. The sliding gears are only supported by pins on one side in this example but no obstacle to including outrigger support.
I guess smaller power ratings to prove the concept would be a safe way forward.

Arnold Garnsey

In hindsight ( no delete option) Other utube videos show the idler chain and 'gears stay fully aligned and with accurate timing there should be no load on components during shift.

Lad

The improvement in range is surprising and welcomed as long as it doesn't become a point of failure.

GasperG

This type of shifting is only possible with electric motor, because it must cooperate and change load instantly without driver noticing it. I thing Renault is doing something similar with their hybrid without a clutch. No matter how instant the shift is, it means that motor must suddenly change rpm and that the motor is the integral part of transmission, you can't just bolt this thing to an EV and expect it to work.

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