On a 1% gradient, a 38-ton diesel vehicle needs 312 hp to maintain 70 km/h, and on 2%, 410 hp. The only practical way of increasing horse power is raising the mep, which must however be accompanied by increased air supply to avoid exhaust pollution. The best way of doing this is turbocharging. This makes higher power, smaller dimensions, lower fuel consumption, cleaner exhaust and noise reduction possible. At low rpm the turbocompressor must be combined with an exhaust regulator; this slightly reduces torque on starting. Specific fuel consumptions as low as 150-170 g/h/hp are possible today. Exhaust is quite clean; NOX is somewhat high but can be cut, for a somewhat higher fuel consumption. Development towards higher power is impossible without turbocharging; the engine must, however, be designed for the higher stresses and higher temperatures. Temperature can be reduced by improved cooling, and stresses by reduction of the maximum pressure. The latter is possible by reduction of the compression ratio, but this makes for worse cold starting and idling characteristics. This can be remedied by fitting an electric heater in the inlet manifold and by restricting exhaust flow. Exhaust temperature of 800 degrees C and mep of 17 kgf/cm. sq. on full rpm are already possible. /TRRL/

  • Corporate Authors:

    Swedish Engineers' Press Limited

    P.O. Box 5703
    G11487 Stockholm,   Sweden 
  • Authors:
    • Haeggh, B
  • Publication Date: 1975


  • Swedish

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00137557
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Files: ITRD, TRIS
  • Created Date: Oct 26 1976 12:00AM