Schaeffler Demonstrates STEP2 Electric Car With 2-Speed Gearbox

3 years ago by Mark Kane 10

Schaeffler STEP2

Schaeffler STEP2

Schaeffler STEP2

Schaeffler STEP2

Last month, Schaeffler presented its STEP2 electric concept car at the Silvretta E-Rally in Montafon, Austria, the vehicle is equipped with a 2-speed powershift transmission and a drive unit from Schaeffler subsidiary IDAM.

For Schaeffler, this is not its first try to present a new EV solutions with an electric axle, as in 2013 they debuted the Ford Fiesta E-Wheel Drive with an electric wheel hub drive.

This year, Schaeffler was demonstrating how a 2-speed transmission can increase efficiency of an electric car.

Uwe Wagner, Vice President R&D Automotive at Schaeffler stated:

“With a two-speed gearshift system, a low ratio for high tractive force and a high ratio for good overall efficiency also at high driving speeds, we offer higher dynamics and at the same time we achieve a longer range of electric operation.”

According to the press release, the Silvretta E-Rally STEP2 was more efficient by approximately 6% compared to a similar vehicle with only one gear.

For a typical EV with 80 miles of real world range, 6% translates to about 5 miles of additional range (or alternatively a smaller battery pack could be used to achieve the same range). For a 200-mile EV, 6% would increase the range by some 12 miles.

“In simulations and test drives, the STEP2 concept vehicle has already achieved a significant reduction in consumption (as energy withdrawn from the battery) of around six percent compared to a comparable vehicle with only one gear. STEP2 is based on a volume-produced compact car. Schaeffler engineers removed the internal combustion engine, the manual six-speed transmission and the fuel tank. The front axle was also modified but the wheels, brake system and steering system were left in original condition. The electric motor was supplied by the Schaeffler subsidiary IDAM (INA – Drives & Mechatronics GmbH & Co. KG), the specialist for direct drive technology. As an electric vehicle, the Schaeffler STEP2 is now driven by an electric motor, which can be coupled with two ratios via a transmission. The transmission comprises a planetary gear set, wet multi-disk clutch, band brake and a lightweight differential. The first and second gear ratios are produced in the transmission by a lternately closing the brake and clutch. The vehicle`s battery is located in place of the fuel tank and exhaust gas system below the passenger cell. The Schaeffler STEP2 has a system output of up to 70kW (peak) and 50kW in continuous operation.”

“Schaeffler`s engineers from the electric mobility sector gained further findings under actual alpine driving conditions during the three alpine stages and demonstrated in the field of mainly standard electric cars that the use of a transmission leads to even greater efficiency savings in terms of kilowatts, volts and amperes. The electric mobility sector at Schaeffler is involved in the development of solutions for all future mobility concepts and with its research and development work for and in collaboration with customers makes a valuable contribution to the mobility of the future.”

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10 responses to "Schaeffler Demonstrates STEP2 Electric Car With 2-Speed Gearbox"

  1. The real-world beniefit would be ~6% increase in range, vs. cost savings provided by an efficiency increase.

    At $500 per year in electric use ($0.12/kWh) would only mean a $300 savings after 10 years. 6% increase on an 80 mile range is an extra 5 miles. On a 300 mile PEV, 6% could provide close to 20 miles extra range.

    The consideration is how often the extra range would be needed weight against added expense of having a two-gear option. Also, with normal battery degration of 2-4% per year, the 6% gain only makes a difference of a year, or two in operational capabilities.

    Interesting idea, not sure if automanufactures will consider such an option. It will be a choice of adding a more complex gearbox vs. designing is a couple more kWh of battery. What would you choose?

  2. ggpa says:

    Running costs on an EV is so low already, that a 6% saving will not pay for extra mechanical complexity.

    I recall the first Tesla Roadsters also experimented with a two speed transmission …

    Perhaps the most beneficial use of this technology is to add a lower ratio for commercial vehicles that might in some cases be loaded heavily and need extra torque …

  3. MikeM says:

    I loved this bit: “.. . even greater efficiency savings in terms of kilowatts, volts and amperes”

    Wow! I’ll bet yet greater savings can be had at power levels expressed in terms of ergs per fortnight.

    1. MikeM says:

      No. Wait. I meant Joules per hour. Or something.

      1. GSP says:

        🙂

        I think we should standardize on ergs/fortnight. Much more interesting than those old Watts or HP.

        GSP

  4. Djoni says:

    Interesting but not as much as build a more powerful motor/invertor unit with a higher ratio to achieve the same.
    With increase C factor of battery coming in the near future, this is very possible.
    Or go for a four wheel drive with two motor and different ratio front and rear.
    You gain more regenrative energy, wich will be more than 6% up EAR and you use mainly the traction motor that is most efficient at ever condition you’re in.
    Let say 70%/30% for the low speed in favor of the short ratio motor and the opposite for the high speed or/and just let the low ratio motor free spinning.
    How about that?

  5. I agree that a multi-gear transmission is more complexity for very little benefit.

    Given that we know how to improve the efficiency of EV’s by about 50% by lowering the Cd of the car, by free wheel coasting, and by reducing losses in the drivetrain and the battery management.

    Case in point is the Illuminati Motor Works ‘7’ which has a 220+ mile range with it’s 33kWh battery pack. It uses just ~130Wh/mile at 60-70MPH on flat ground and low wind. The IMW ‘7’ is a 2,900 pound four seat electric car, with 0-60MPH acceleration of ~6.5s.

    1. Warren says:

      Neil,

      Unfortunately, most would rather cook the planet than be caught in a car with fender skirts…slaves to fashion.

  6. Someone out there says:

    I guess the 2 speed gearbox could be used as a component of an ‘eco’ mode.
    In one gear the car has a speed range of 0-70 mph with an electronic limitation on the inverter to save power by limiting acceleration.
    In the other gear the car has the full speed range of say 0-110 mph and no acceleration limitation.