Computer simulation techniques have been used to study the effect of gross vehicle weight and other design and operating factors on fuel consumption and fuel utilization of articulated vehicles. Vehicles were classified by gross vehicle weight and body type. For each class a representative vehicle was selected and its fuel consumption and fuel utilization were calculated over a representative duty cycle. In addition, plausible modifications were made to vehicle and engine design and operating parameters. The effect of these changes was evaluated. The results show that some gross vehicle weight configurations above the present legal limit of 32.5 tonne can yield improvements in fuel efficiency provided that existing load factors are maintained. If a fleet were composed of vehicles on 5 axles at 38 or 40 tonne gross weight these fuel savings might be gained without causing additional road damage, if the fourth power law relating road damage to axle weight is applied. The use of vehicles on 4 axles at 36 tonne gross weight and on 5 axles at 44 tonne gross weight would increase road damage. Single-drive configurations are 4 to 5 per cent more fuel efficient than double-drive configurations. An example of a package of possible economy measures has been shown to give 18 per cent improvement, which includes the construction of lighter tractive units and trailers, reductions in aerodynamic drag using a low governed speed engine matched to a suitable transmission and the use of a demand actuated cooling fan. (Author/publisher)
Samenvatting