Commercial vehicle automatic transmissions which will save fuel and be less expensive were discussed at the March Solihull Conference. Future automatic gearboxes will use differential gearing between input and output with the reaction from the differential fed into a torque converter or hydrostatic drive. A torque multiplication of 5 to 1 can be obtained using this method. Details are given of servo hydraulic systems currently being investigated in West Germany and the University of Bath. The National Engineering Laboratory (NEL) at East Kolbride is developing a pure hydrostatic transmission with an efficiency of about 76 per cent which has been used to equip a daimler rear-enged double-decker bus. A regenerative braking system is also used by NEL to store the energy used in slowing the bus. Design features of new and existing types of hydrokinetic transmissions were also discussed. Results given from trials with buses and commercial vehicles show little difference in fuel consumption of automatics when compared with manual gearboxes. Defects in some forms of semi-automatic bus transmissions were discussed. The possible use of torque converters to reduce the number of gear ratios was examined, and the general question of initial cost compared with running cost was discussed. /TRRL/

  • Availability:
  • Corporate Authors:

    Embankment Press Limited

    Building 59, GEC Estate, East Lane
    Wembley, Middlesex HA9 7TQ,   England 
  • Authors:
    • Dickson, S
  • Publication Date: 1978-5


  • English

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 19-23
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00182737
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Oct 31 1978 12:00AM