Mack develops ultracapacitor hybrid truck for US Air Force

Mack Trucks have developed a hybrid Granite® dump truck, built for the Air Force’s Advanced Power Technology Office at Nellis Air Force Base in Nevada.

Mack Granite dump truck

The Mack hybrid electric power train features an integrated starter, alternator and motor referred to collectively as an electric machine. The electric machine assists the vehicle’s MP7 diesel engine in providing torque to the wheels and regenerates energy during braking. This energy (stored in ultracapacitors) is then used in place of diesel fuel. This technology provides the maximum fuel savings on routes with frequent braking and accelerations, particularly refuse collection and urban delivery, as well as certain construction applications.

Mack hybrid powertrain


Type: Mack Model: MP7 – 365M, 11-liter turbocharged diesel
365 hp @ 1500-1900 RPM

Electric Machine:
Type: Permanent Magnet; Synchronous Motor
Power: 161 hp peak; 94 hp continuous
Torque: 590 lb-ft. peak; 295 lb-ft continuous

Energy Storage
Type: Ultracapacitors
Usable Energy: 582 watts
Voltage: 300-725 volts DC

Type: 12-speed automated manual

Source: Mack via ConstructionPros


5 Responses

  1. Nice! Though, for a second I thought that EEStor’s battery-killing ultracapicitor had snuk onto the market without me noticing.

  2. Not being an ultracapacitor guru makes it a bit difficult to determine how much energy is being stored and recovered in this application. If anyone can provide further insight it is welcome. Likewise for anyone who knows where Mack sourced their ultracapacitors for the Granite.

  3. why cannot people understand simple physics. the watt is a unit of power ie energy per unit time. —
    usable energy must be expressed in watt-hours. this is important in the understanding of the ultracapacator’s performance. yet this simple, important consideration is missing. stupid stupid people!

  4. Charles, I’m pretty sure Mack understand simple physics. If they’ve not used the correct units then that is either an accidental omission or a deliberate ploy to prevent you physics genii from working out how much energy they are storing. I was hoping someone could take the numbers Mack has made available and calculate some information that is meaningful to interested people.

  5. When can we test one, or even drive one?

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