Volvo Fuel Su­per Truck

Owner Driver - - Your Say -

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

Keirav­ille, NSW

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