Machine Design

Scanning for Ideas: Speed increaser lets idling engines power electronics

Edited by Stephen J. Mraz

When a vehicle idles, engine rpm is often too low to run the alternator/generator at a high enough level to power accessories, so the vehicle’s electronic controls rev the engine to compensate. A more-efficient approach is to use the Single Axis Speed Increaser from Ogura Industrial Corp., Somerset, N. J.

The device consists of an electromagnetic coil, planetary gear with an embedded permanent-magnet ring, and a planetary carrier/pulley. When there is no power applied to the coil (normal driving), the permanent magnet locks the ring gear to the planetary carrier/pulley. This drives at a 1:1 ratio because all components are operating at the same speed. But when the vehicle is stationary and the alternator cannot supply power to all the electric accessories, the coil is powered up, locking the ring gear in place. The coil flux disrupts the field of the permanent magnet, creating an air gap between the ring gear and planetary carrier. With the outer ring gear locked in place, the input pulley turns the planetary carrier which, in turn, drives the sun gear. The gear ratio provides an approximate 3:1 speed increase to the sun gear, which then spins the accessory driveshaft at the higher rpm level.

The increaser transmits up to 10 Nm of torque at speeds to 1,000 rpm in the 1:1 ratio and 50 Nm in the 3:1 ratio when the coil is engaged. It operates on 24 Vdc and can withstand temperatures from –30 to 300°F. It is well suited for buses and RVs, vehicles that can have significant electric loads even when idling. It will also work with other engine accessories that need higher operating speeds such as superchargers, pumps, and compressors to save fuel.

© 2011 Penton Media, Inc.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.