Volvo Fuel Super Truck
Regarding ‘Drag-defying combo’ (Owner//Driver, September 2018, p25) and ‘Astro: The Fuel Saver’ (Owner//Driver, September 2018, p78).
I offer these comments on the rig design depicted in the stated articles, including:
The vehicle’s ground clearances vividly do not satisfy those specified in ADR 43 clause 6.4. Furthermore, the rig must not provide sufficient relative movement between vehicle components necessary for operation on local roads, including the Hume Highway. Even here provision of liberal relative movement between vehicle units is necessary to manoeuvre over causeway type road conditions.
Noting that Australia exhibits one of the highest ambient temperatures with gross input of solar radiation directly to our roadways, it is paramount to optimally cool heavy vehicle tyre walls at all times. The depicted rig severely deviates from this paramount requirement, especially on the trailer units.
Furthermore the trailer units suggest it would be a nightmare for a driver to effect a tyre change at a remote site.
Operators must also be aware that brakes convert a rig’s kinetic energy into thermal energy. The latter thermal energy must be dissipated by ample air flows. If the air flow is minimal, the trailer undercarriage and, in turn, the cargo, receives the thermal input. Hence with the depicted rig there would be an increased risk of rig and freight loss due to fire, with the risk significantly exacerbated by the local high ambient temperatures mentioned above.
Finally, the latest NTI NTARC 2017 Major Accident Report (Covering Major Accidents in 2015) identified that 10 per cent and 5 per cent of heavy vehicle loss by fire is due to trailer wheel bearings and brake fires respectively. On the proposed rig how would a driver observe the rear axle is smoking and/or alight? Once a fire is identified, at say the rear axle, how would the driver and/or emergency personnel apply fire extinguishing treatment?
Sorry Volvo and the trailer manufacturer, it is back to the drawing board. Far greater fuel consumption improvements can be effected to heavy vehicles by adopting dynamic load sharing inherently damped fractional feedback ride height-controlled air suspensions on each axle group relative to that generated by application of aerodynamic treatment. Adoption of the same suspension technology also attracts numerous other significant advantages and operation savings.
Improved aerodynamic treatments, applied secondary to the aforementioned paramount considerations, are possible. These relatively low fuel efficiency gain aerodynamic improvements require a completely different and thorough design approach necessitated by the local extreme ambient temperature conditions. Arnold McLean