A tank filled to the top has no air inside and the liquid barely moves. The trouble starts at half load and on the last drops of the round, when ten or fifteen thousand litres are left loose in a large compartment. Brake, and that mass keeps going forward and shoves the truck. Pull away, and it swings back and pulls the other way. Internal baffles slow the wave down but don't remove it, and any tanker driver knows when the load is half empty because the truck answers late. Add a map that dumps all the torque the moment you touch the pedal and you get that wave moving exactly when you don't want it, on a roundabout or a slip road.
The drum never stops. It turns while loading, it turns for the twenty minutes of the trip and it keeps turning on site until discharge, because if it stops the concrete starts to set and the load is lost. That power take-off draws engine power the whole time, even at idle at a red light. Then there's the clock: from loading to discharge there's a window of around ninety minutes, so every minute lost pulling away loaded on a site ramp comes straight out of the load's own margin. A mixer spends half its shift between 900 and 1,400 rpm with the drum engaged, and that's the range that matters.
On both trucks we work on boost pressure and injection maps to bring torque forward to the low end, but with a progressive curve instead of a step. That's the difference from a long-haul map: we're not after the highest peak, we want the rise to be smooth so the liquid load stays controlled and so the mixer's power take-off runs at a steady engine speed. We don't touch the speed limiter, which adds nothing on these trucks. We don't touch the SCR, the EGR or the particulate filter, so AdBlue and regenerations carry on as before and the truck keeps its type approval. We keep the coolant and exhaust gas temperature protections, which climb higher on a truck pulling slowly under load than on a motorway run. And we save the original software before touching anything.
A tanker or a mixer standing still is a round that doesn't happen, so moving the fleet to a workshop costs more than the work itself. For fleets we travel to the customer's own base anywhere in Europe and work vehicle by vehicle, so no unit is off the road for longer than its own remap takes. We measure fuel consumption before and after using the same route, the same load and the same driver, and hand over a report per vehicle, because the on-board computer is no use for comparing. Pricing starts at 600 euros per vehicle, with volume rates from ten units.
Yes. Boost pressure and injection are tuned to bring torque forward to the low end, but with progressive delivery rather than a spike, so a half-full load of liquid stays controlled when pulling away or braking. The emissions system and the speed limiter are left untouched.
The drum is driven by the power take-off, which needs a steady engine speed. Remapping aims at exactly that: more torque available between 900 and 1,400 rpm so the engine holds its speed with the drum engaged without labouring. Drum rotation speed itself isn't controlled by the engine ECU.
Because a tractor unit runs at steady revs with a fixed load and these two trucks do not. In a half-full tanker the liquid moves and a sharp step in torque stirs it; in a mixer a power take-off draws power continuously. Both want a progressive low-end curve, not a peak figure.
Not for fleets. We travel to the customer's base anywhere in Europe and work vehicle by vehicle, so each unit is only off the road for as long as its own remap takes. We measure consumption before and after on the same route with the same load, and hand over a report per vehicle.